Background: Flexible flatfoot is a common pediatric condition characterized by a reducible loss of the medial longitudinal arch during weight-bearing. While subtalar arthroereisis is widely used for its minimally invasive correction, long-term outcomes-particularly arch stability after implant removal-remain poorly understood. This study evaluates radiological and functional changes from implant insertion to removal in adolescent flatfoot patients. Methods: A retrospective analysis of 21 adolescents with flexible flatfoot who underwent subtalar arthroereisis followed by implant removal was conducted. Radiographic parameters (hindfoot valgus angle, talonavicular coverage angle, etc.) and functional scores (AOFAS, VAS) were assessed preoperatively, postoperatively, and at final follow-up (mean 8.2 years). Results: Subtalar arthroereisis significantly improved deformity and function. The hindfoot valgus angle reduced from 11.6° ± 7.8° to 1.3° ± 4.3° postoperatively, AOFAS score increased from 68.3 ± 6.2-95.5 ± 3.0. The talonavicular coverage angle was 26.2 ± 11.4° preoperatively, decreased to 10.1 ± 5.9° postoperatively. The talar pitch angle was 40.9 ± 6.0° preoperatively, decreased to 29.3 ± 3.4° postoperatively. The calcaneal pitch angle was 14.2 ± 2.2° preoperatively, increased to 16.9 ± 2.9° postoperatively. The lateral Meary's angle was -24.4 ± 6.9° preoperatively, improved to -8.1 ± 3.5° postoperatively. The AOFAS score increased from 68.3 ± 6.2 preoperatively to 95.5 ± 3.0 postoperatively, meanwhile, the VAS score decreased significantly from 3.5 ± 1.2 preoperatively to 1.3 ± 1.1 postoperatively. However, mild arch recurrence occurred after implant removal (The talar pitch angle increased to 32.6 ± 3.3° at the final follow-up. The lateral Meary's angle increased to -12.9 ± 3.6° at the final follow-up after implant removal.), though values remained superior to preoperative levels. Conclusion: Following subtalar arthroereisis implant removal, adolescents with flexible flatfoot demonstrate mild arch recurrence; nevertheless, radiological outcomes sustain substantial improvement relative to the preoperative condition.

Introduction: This study aims to assess the functional and radiological outcomes of combining minimally invasive medial displacing calcaneal osteotomy (MDCO) with subtalar arthroereisis (STA) for the treatment of symptomatic planovalgus feet in young adults. Methods: A single-centre, prospective cohort study was conducted between November 2015 and February 2022. The study included a total of 32 patients with flexible flatfoot who were treated with subtalar arthroereisis combined with medialising calcaneal osteotomy with at least three years of follow-up. Radiographic evaluation included talar coverage angle, AP talo-first metatarsal (T1MT), AP talo-calcaneal, lateral talo-first metatarsal, and calcaneal pitch angles. Function was assessed by the AOFAS score. Results: Angles and scores were compared preoperatively and at the third-year follow-up. The mean talo-navicular coverage angle TNCA reduced from 32.72° (±8.33) preoperatively to 8.84° (±5.70) at the last follow-up. The mean AP T1MT improved from 21.59° (±8.47) preoperatively to 7.78° (±4.03) at three years postoperatively. Meary’s angle decreased from 20.84° (±7.14) preoperatively to 4.78° (±3.20) following the correction. The mean preoperative AOFAS score was 62.69 (±9.26), and significantly improved to 94.19 (±3.80) at the last follow-up. Four feet experienced sinus tarsi pain (12.5%), and three patients (9.3%) needed removal of the arthroereisis implant. Conclusions: The combination of MDCO and STA holds significant promise for treating flexible flatfeet in adolescents and young adults, particularly in cases of moderate to severe deformity. This combination demonstrates a synergistic interaction, with the STA implant providing internal bracing to support MDCO and reducing stresses over the medial arch by preventing hyper-pronation. Simultaneously, the MDCO reinforces the reconstruction, achieving the necessary increased correction in moderate to severe flatfoot cases, while also reducing stresses over the STA implant.

Background: Subtalar arthroereisis is used for the surgical correction of flexible planovalgus and in adults is often used as an adjunct to a multi-step procedure. The theorised role of subtalar arthroereisis in adults is to offload the medial soft tissue reconstruction achieved during flexible planovalgus correction to facilitate fibrosis and healing. A common complication is sinus tarsi pain caused by the subtalar implant, with symptoms often only improving upon implant removal. Methods: This single-surgeon case series analysed an adult population who underwent surgical correction of flexible planovalgus to identify the rate of subtalar implant removal. Data was collected from local online operating systems and all operations occurred between August 2022 and May 2024. Those who met the inclusion criteria were retrospectively followed up using clinic letters for one year or until discharged if prior to one year of follow-up. Results: Ten patients met the inclusion criteria and the subtalar implant used in all of these was the Arthrex ProStop® arthroereisis screw. The size of implants used were 7 mm, 8 mm or 10 mm. Nine patients did not experience any complications. One patient required subtalar implant removal due to sinus tarsi pain which, upon further investigation, was due to subtalar implant migration. Symptoms resolved upon implant removal. Conclusion: Within the adult population in this case series, there was a subtalar implant removal rate of 10% (95% CI 0.3 - 44.5%; Clopper-Pearson exact) after one year of follow-up. This was based on arthroereisis implant sizes of 10 mm or less. Further large-scale studies are required to verify whether using implants within this size range could obviate the routine removal of the implants in the management of flexible planovalgus in the adult population, unless symptomatic.

Background: Flexible flatfoot is a common musculoskeletal disorder in adolescents, which is characterized by a collapsed longitudinal arch. A common surgery like subtalar arthroereisis depends on the implant in sinus tarsi. Optimal match between them can potentially avoid postoperative pain and obtain improved prognosis. Investigations into anatomical morphology of sinus tarsi by weight-bearing CT (WBCT) may unveil the pathogenesis and facilitate the treatment of flexible flatfoot. Methods: This retrospective study included 28 control cases and 42 flatfoot cases. The sinus tarsi length (STL), the sinus tarsi width (STW), the angle between its long axis and the horizontal line (ST-H angle), the sinus tarsi angle (ST angle), and the tibial width were measured. We also calculated two ratios (STL/tibia width and STW/tibia width) to standardize individual differences. Data analysis was conducted via mean/median comparisons and subsequent linear regression. Results: The STL and the STL/tibia width were significantly greater in the flatfoot group (25.73 ± 3.50 vs. 23.09 ± 3.77 mm, p = 0.004; 0.90 ± 0.15 vs. 0.81 ± 0.14, p = 0.009). The ST angle was significantly smaller in the flatfoot group by an average of 4.63° (13.20° vs. 17.83°, p < 0.001). Linear regression revealed that female gender and smaller ST angle were significantly correlated with higher Meary angle, while smaller ST angle and greater STL/tibia width were significantly correlated with lower Pitch angle (p = 0.002, p = 0.007; p = 0.003, p = 0.004). No statistical predictive effects were observed for the other variables. Conclusions: The ST angle and STL/tibia width may serve as auxiliary parameters for implant selection in subtalar arthroereisis to improve sizing match within the sinus tarsi.

Purpose: Subtalar arthroereisis is a minimally-invasive technique for the treatment of flexible flatfoot. Some issues regarding the procedure are still debated, such as post-operative management. The aim of this study is to offer a review of the pertaining literature to identify current post-operative protocols and describe possible differences among them. Methods: We searched the PubMed database for all papers related to subtalar arthroereisis in children specifying the post-operative protocols. After reviewing all studies according to excluding criteria, 50 articles were selected for analysis. Results: Based on the literature review, different post-operative protocols emerged in the treatment of patients undergoing subtalar arthroereisis, in particular regarding length of hospital stay, type and duration of immobilization, weight-bearing management, adopted rehabilitation scheme, sport resumption and implant removal. Conclusions: The most important finding was the existence of a wide variety in post-operative management after subtalar arthroereisis in children, thus confirming that no clear consensus still exists in this field.

Purpose: Although subtalar arthroereisis (SA) with HyProCure is increasingly utilized for progressive collapsing foot deformity (PCFD), evidence regarding risk factors for complications remains limited. This study aimed to analyze the influencing factors and correlations of sinus tarsi pain and implant removal in PCFD patients after SA utilizing the HyProCure device. Methods: A retrospective study was conducted involving 223 patients (236 ft) diagnosed with PCFD who underwent SA from June 2015 to June 2023. General data and surgical data such as patient gender, age, body mass index (BMI), surgical side, any adjunctive surgeries, length of stay, HyProCure size, and HyProCure depth were collected. Complications were also recorded. Statistical analysis included normality assessment, inter-group comparisons (t-tests for normal quantitative data, Mann-Whitney U for non-normal data, and chi-square for categorical variables). Spearman correlation analyzed factors associated with sinus tarsi pain and implant removal. Binary logistic regression identified risk factors. Results: From 2015 to 2023, a total of 60 cases with sinus tarsi pain, with an incidence rate of 25.42%. Spearman correlation analysis showed that sinus tarsi pain was positively correlated with BMI (r = 0.159, p = 0.014), length of stay (r = 0.165, p = 0.011), and HyProCure depth (r = 0.501, p < 0.01). HyProCure removal was positively correlated with HyProCure depth (r = 0.521, p < 0.01) and sinus tarsi pain (r = 0.700, p < 0.01). In the analysis of sinus tarsi pain, the primary risk factor in patients with PCFD was identified as length of stay (OR = 1.456, 95% CI 1.113-1.904) and HyProCure depth (OR = 2.156, 95% CI 1.690-2.750), both of which were statistically significant (p < 0.05). Among the cases of sinus tarsi pain, 36 patients underwent HyProCure removal, leading to an incidence rate of 15.25%. Regarding the removal of HyProCure, the primary risk factor identified was HyProCure depth (OR = 2.531, 95% CI 1.849-3.463), which was statistically significant (p < 0.05). In particular, no significant correlation was observed between HyProCure size and sinus tarsi pain or implant removal (p > 0.05). Conclusion: In patients with PCFD, length of stay was correlated with the incidence of sinus tarsi pain. Additionally, HyProCure depth was linked to both the incidence of sinus tarsi pain and HyProCure removal. Our research suggests that the prognosis is better for PCFD patients with a shorter length of stay and a reduced HyProCure depth.

Objective The treatment of talocalcaneal coalition (TCC) with pes planus deformity in adolescent patients still presents challenges. With the pes planus deformity untreated, the final clinical outcome would be compromised. Therefore, simultaneous correction of pes planus deformity seems to be of great importance. This study aimed to retrospectively evaluate the clinical efficacy of coalition resection combined with extra-osseous talotarsal stabilization (EOTTS) treatment for adolescent TCC with pes planus deformity. Methods Data was reviewed for patients of TCC and pes planus deformity treated by coalition resection and EOTTS from January 2018 to January 2024. Meary's angle and talar-1st metatarsal angle (T1MA) were measured to assess the alignment improvement (paired sample t-test). Visual analog scale (VAS) for pain (Wilcoxon signed rank test) and American Orthopedic Foot & Ankle Society ankle-hindfoot score (AOFAS-AHS) (paired sample t-test) were evaluated for the overall clinical outcomes. Time to return to sports activity and complications were also recorded. Results No early wound or soft tissue complications occurred. At 1-year follow-up, Meary's angle and T1MA improved from 13.4° ± 5.2° to 5.1° ± 3.4°, and from 14.7° ± 3.7° to 6.4° ± 2.5°, respectively. The median VAS score decreased from 5 to 0, while the AOFAS-AHS increased from 51.1 ± 8.9 to 90.1 ± 9.3 (all p < 0.05). Fifteen patients returned to sports at a median of 3 months (range: 2–4 months). One patient experienced sinus tarsi pain, which was resolved after implant removal at 14th month postoperatively. Conclusion Simultaneous coalition resection and EOTTS for adolescent TCC with pes planus deformity achieves satisfactory clinical outcomes with minimal complications.

Introduction: Conservative treatment in flexible flat foot (FFF) is preferred in most cases; only in symptomatic and conservative-refractory cases is surgical treatment proposed. Subtalar arthroereisis (STA) is a well-established technique, but there remains a paucity of information surrounding the effectiveness and outcome. The aim of this study was to evaluate radiological and functional outcome of STA in FFF. Material and methods: This study is a case series of 15ft with symptomatic FFF treated by STA from a period of 2018-2024. Mean age at the time of surgery was 10.1±0.83 years. There was a significant increase in both American Orthopaedic Foot and Ankle Society score (AOFAS) and The Oxford Ankle Foot Questionnaire for Children (OxAFQ-C) subjective scoring with p-value of <0.001. Degree of valgus correction was statistically significant (p=0.001). There were significant differences between pre-and post-operative lateral radiographic measurements with p-value of <0.005. One patient with the lowest radiological angle of correction and increased femoral anteversion had loosened implant in two years follow-up. Results: Despite results in earlier studies, recent evidence, including randomised control trials, supports the reliability of STA in managing FFF, advocating its use over traditional osteotomies due to fewer complications and quicker rehabilitation periods. In our study, all subjects had significant improvement in lateral radiographic measurements and subjective scoring evaluation during follow-up. Conclusion: STA is an option for surgical treatment in symptomatic FFF patients. In this study, all presented subjects showed overall satisfying functional and radiological outcome.

Background: Flexible flatfoot with painful accessory navicular poses a significant therapeutic challenge in adolescents, with no consensus on optimal surgical management. This meta-analysis evaluates the efficacy of subtalar arthroereisis (STA) combined with the Kidner procedure for this condition. Methods: We systematically searched 6 databases (PubMed, Embase, Cochrane Library, Web of Science, CNKI, Wanfang) up to (insert date). Eight studies involving 249 participants met inclusion criteria. Standardized mean differences (SMDs) with 95% confidence intervals were calculated for radiographic parameters (Meary's angle, talus-first metatarsal angle [T1MT], talonavicular coverage angle [TCA]), pain (visual analog scale), and function (American Orthopaedic Foot & Ankle Society Score [AOFAS]). Heterogeneity and publication bias were assessed using I² statistics and Egger's test. Results: The combined procedure significantly improved all measured outcomes: Meary's angle (SMD -3.71, 95% confidence interval, -4.90 to -2.51), T1MT (SMD -2.63, -3.69 to -1.57), TCA (SMD -2.65, -4.29 to -1.01), visual analog scale (SMD -4.36, -5.17 to -3.54), and AOFAS (SMD 4.85, 4.25-5.44). Compared to STA alone, the combination showed superior correction of T1MT (SMD -0.35, -0.66 to -0.04) but no significant differences in other parameters (AOFAS: SMD 0.80, -0.45 to 2.05; TCA: SMD -0.68, -1.67 to 0.31). Conclusion: STA with Kidner procedure effectively corrects deformity and improves function in adolescent flexible flatfoot with accessory navicular. While superior to STA alone in T1MT correction, most outcomes were comparable between approaches. These findings support the combined technique as a viable surgical option for this challenging condition.

Background: Flatfoot is a common foot disorder involving progressive foot deformity of the three-dimensional structures of the forefoot, midfoot, and hindfoot. Currently, Chinese surgeons and patients favor subtalar arthroereisis (SA) due to its minimally invasive and low-damage characteristics. HyProCure device is widely used. However, there is limited analysis of large sample sizes. This study utilized statistical evaluation with a large sample size to analyze clinical characteristics trends of SA for flatfoot, including baseline indicators, selection of HyProCure size and surgical strategy, complications, and implant removal. This study will enhance the understanding of SA in China. Methods: A retrospective analysis of 732 patients (1008 ft) who underwent SA from June 2015 to June 2023, with 509 pediatric and adolescent patients (772 ft) and 223 adult patients (236 ft). Based on the patient's age, patients aged ≤ 18 were included in the children and adolescent group, while adult acquired flatfoot deformity (AAFD) patients aged > 18 were included in the adult group. General data was collected, including patient sex, age, side, body mass index (BMI), surgery date, HyproCure size, and surgical data, and trends were analyzed. Postoperative complications and HyProCure removal were collected as outcome measures during follow-up. Results: The age of patients treated with SA was gradually getting younger, with male patients predominating, mainly concentrated in the 11-14 age group. HyProCure 7 has the highest usage rate. In the children and adolescent group, 288 ft (37.31%) only underwent SA. In the adult group, 18 ft (7.63%) only underwent SA. Complications include sinus tarsi pain, peroneal spasms, achilles tendon tension, and muscle strength decline. The complication rate in the children and adolescent group was 5.05%, while in the adult group it was 28.81%. Overall, it was 10.62%. The removal rate of HyProCure in the children and adolescent group is 1.04%, in the adult group is 15.25%, and overall is 4.37%. Conclusions: The trend in flatfoot treated with SA was towards children and adolescent male patients, and sinus tarsi pain was the most common complication after SA. The complication rate and removal rate in the children and adolescent group were lower than those in the adult group. HyProCure can be removed without additional adverse effects.

Background/Objectives: Subtalar arthroereisis (STA) is a widely used surgical procedure for symptomatic pediatric flexible flatfoot. However, implant migration remains a concern due to its potential impact on long-term correction and complications. This study evaluated the migration pattern of STA implants and assessed long-term clinical and radiographic outcomes. Methods: This retrospective cohort study included 47 feet from children aged 8-13 years who underwent STA with adjunctive soft tissue procedures between 2014 and 2018, following ≥6 months of failed conservative treatment, with a minimum follow-up of 5 years. Exclusion criteria included neuromuscular or rigid flatfoot. Weight-bearing radiographs assessed anteroposterior (AP) and lateral Meary's angles, reflecting forefoot-to-hindfoot alignment, and calcaneal pitch, indicative of longitudinal arch height. Implant migration was recorded and clinical outcomes were measured by the American Orthopedic Foot and Ankle Society (AOFAS) score. Measurements were recorded preoperatively, immediately postoperatively, and at 1 month, 3 months, 6 months, 1 year, and 5 years. Results: Radiographic correction was significant and sustained at 5 years. The AP Meary's angle improved from 13.09° to 5.26° at 1 month and 6.69° at 5 years (p < 0.001); lateral Meary's angle from 9.77° to 4.06° and 4.88° (p < 0.001); and calcaneal pitch from 14.52° to 16.87° and 16.89° (p < 0.001), respectively. AOFAS scores increased from 67.52 to 90.86 at 1 month and 96.33 at 5 years (p < 0.001). Implant migration peaked within the first postoperative month (mean: 3.2 mm on ankle AP view; 3.0 mm on foot AP view) and stabilized thereafter. Four cases of complications included implant dislodgement, subsidence, and persistent sinus tarsi tenderness, which were successfully resolved after appropriate management. No recurrence of deformity was observed. Conclusions: STA implant migration is most pronounced during the first month, likely due to physiological settling as the foot adapts to altered biomechanics. With appropriate implant selection, technique, and follow-up, migration does not compromise long-term correction or outcomes. In general, symptomatic cases can often be managed conservatively prior to implant removal.

Tarsal coalition can be a long term severely disabling condition. For symptomatic cases with flatfoot surgical resection of coalition and subtalar arthroeresis represents the most common treatment. Literature reports variable outcomes and recurrence. The aim was to achieve optimal correction with no recurrence. This retrospective study presents, reporting results, an innovative technique that provides numerous advantages and improved outcomes. Nineteen patients suffering from painful flatfoot from tarsal coalition were, consecutively, surgically treated by resection of tarsal coalition with interposition of a synthetic flexible bioresorbable polymers membrane as an adhesion barrier and by subtalar arthroeresis. AOFAS scores were used to rate the clinical severity and X-ray/ CT to evaluate the extent of tarsal coalition. Patient's age at time of surgery ranged from 12 to 21. The period examined runs from November 2010 to November 2019. Results were evaluated (up to 9 years follow-up) clinically by AFOAS scores and radiologically by X-ray/CT. AOFAS scores improved in all patients with significant (p < 0.01) pain reduction or disappearance, corrected alignment and increased function, biomechanics of the foot and mobility. X-ray showed no recurrence of coalition in all but one case. There were no complications and patients reported a significant improvement in quality of life. Our study shows that surgical resection of coalition, and correction of flatfoot by subtalar arthroeresis, with the innovative use of a flexible bioresorbable polymers membrane as an adhesion barrier, obtained excellent overall results and importantly prevented recurrence. We believe this technique represents a great option.

Background: Flexible flatfoot is a common foot deformity in adolescents. Subtalar arthroereisis can help reduce excessive foot pronation by placing an implant in the subtalar joint. In recent years, this method has been widely used to treat adolescent flexible flat feet. However, some postoperative complications may occur 3–6 months after subtalar arthroereisis, and few studies have explored plantar pressure and lower limb muscle activation patterns during this period.Methods: Twenty adolescents with flexible flatfoot deformities who underwent subtalar arthroereisis were enrolled in this study. The plantar areas of all patients were divided into eight regions, and the average standing pressure and peak pressure during the gait cycle were compared before and three months after surgery. Surface electromyography (sEMG) of the tibialis anterior (TA), peroneus longus (PL), and medial gastrocnemius (MG) muscles was simultaneously measured during a single gait cycle.Results: All patients were able to walk in their shoes at 3 months postoperatively. After surgery, while standing, the average pressure on the lesser toes, lateral forefoot, and lateral midfoot increased significantly (p < 0.05). In contrast, the pressure of the hallux region, medial forefoot, medial midfoot, medial hindfoot, and lateral hindfoot decreased significantly (p < 0.05). During the gait cycle, the peak pressure in the lesser toes, lateral forefoot, lateral midfoot, and lateral hindfoot increased significantly (p < 0.05), whereas that in the hallux, medial forefoot, medial midfoot, and medial hindfoot decreased significantly (p < 0.05). The maximum lateral displacement of the center of pressure (COP) decreased from 3.81 ± 0.56 cm preoperatively to 3.59 ± 0.41 cm postoperatively. The maximum longitudinal displacement decreased from 21.07 ± 3.96 cm to 19.37 ± 3.08 cm (p < 0.05), and the COP trajectory curve shifted laterally. During the gait cycle, the peak activation percentage of TA significantly decreased postoperatively, that of the PL significantly increased after surgery, and that of the MG significantly decreased. The integral percentage of TA activation was significantly reduced postoperatively. The integral percentage of PL activation was significantly higher than that at the preoperative stage. Additionally, the integral percentage of MG activation was significantly lower than that of the preoperative value. (all p < 0.05).Conclusion: This study found that plantar pressure shifted laterally during the early postoperative period. Such changes in plantar pressure distribution may compensate for alterations in lower limb muscle activation patterns, which may potentially contribute to postoperative plantar pain or painful peroneal muscle spasm. Therefore, monitoring plantar pressure distribution and muscle activation in the early postoperative period is recommended.

Background: Scarf osteotomy is a well-established procedure for hallux valgus, yet recurrence rates range from 3.6% to 10%. Pes planus, which often coexisting with hallux valgus, is a risk factor for recurrence. This study aimed to evaluate the effectiveness of simultaneous correction of hallux valgus and flexible pes planus. Methods: A total of 85 feet with hallux valgus associated with adult flexible pes planus were retrospectively reviewed. All patients were treated with scarf osteotomy (SO). Subtalar arthroereisis using a HyProCure implant (SOH) was performed to correct hindfoot valgus based on shared decision-making. We collected and compared pre- and at least 2 year postoperative clinical outcomes (American Orthopaedic Foot & Ankle Society (AOFAS) forefoot, hindfoot score, Visual Analog Scale (VAS) pain intensity) and radiographic outcomes (hallux valgus angle (HVA), intermetatarsal angle (IMA), Meary's angle, talonavicular coverage angle (TNCA), and calcaneal pitch (CP) angle in both groups. Results: Of the cases reviewed, 51 feet were allocated to SO group, and 34 feet were in SOH group. Recurrence frequency was 5 feet (9.8%) in the SO group, while no recurrences were reported in the SOH group. There was no significant difference in AOFAS forefoot and VAS scores between the groups, However, the SOH group demonstrated significant improvement in AOFAS hindfoot scores and CP angle, as well as a greater reduction in Meary's angle and TNCA, compared to the SO group. Changes in HVA and IMA did not differ significantly between the groups. Three feet in the SOH group experienced sinus tarsi pain, which resolved after removal of the HyProCure implant. Conclusions: Subtalar arthroereisis with a HyProCure implant is an effective treatment option for adult flexible pes planus associated with scarf osteotomy for hallux valgus, leading to a steady improvement in the patients forefoot deformity and increased patient satisfaction at least 2 years postoperatively.

Background: Subtalar arthroereisis (SA) is an increasingly applied minimally invasive approach for flexible flat foot (FFF) not responsive to conservative treatment. This study aimed at evaluating the long-term clinical and radiographic outcomes of SA in pediatric patients with symptomatic FFF. Methods: Thirty-seven patients (11.9 ± 1.6yy) underwent SA (74 feet), with outcomes assessed after a mean 10-year follow-up. Pain, quality of life, foot functionality, and alignment were evaluated using validated tools and radiographic parameters, calculated on weightbearing x-rays pre- and post-operatively. Results: Clinical outcomes reached excellent postoperative results (FFI: 9.1, AOFAS: 94.5) with a low 0.9 NRS pain (p < 0.01) and a 92 % satisfaction. All radiographic parameters improved significantly towards normal values: CP 17.5 ± 3.9, MA 4.3 ± 5.8, TCA 42.8 ± 6.2, TNCA 21.1 ± 8.5, TNU% 26.6 ± 8.4 (all p < 0.01). Conclusions: SA with a metallic endosinotarsal device provided significant long-term clinical and radiographic improvements, with low complication rates and high patient satisfaction, supporting its efficacy as a treatment option for pediatric symptomatic FFF.

Background: The use of subtalar arthroereisis as an adjunct to the surgical treatment of stage 1 flexible progressive collapsing foot deformity (PCFD) is controversial. The aim was to investigate the clinical outcomes and report the implant removal rate of subtalar arthroereisis as an adjunct for stage 1 PCFD. Methods: A retrospective study of 212 consecutive feet undergoing operative management of stage 1 PCFD with adjunctive subtalar arthroereisis between October 2010 and April 2018. The primary outcome was the Foot and Ankle Outcome Score (FAOS). Secondary outcomes included Foot and Ankle Disability Index (FADI), Euroqol-5D-5L Index and implant removal rate. Results: Post-operative clinical FAOS outcomes were collected for 153 feet (72.2%). At mean 2.5-year follow-up, the mean ± standard deviation FAOS for each domain was as follows; Pain: 81.5 ± 18.5, Symptoms: 79.5 ± 12.9, Activities of Daily Living: 82.5 ± 15.4 and Quality of Life: 64.2 ± 23.7. EQ-5D-5L Index was 0.884 ± 0.152. Pre-operative scores were available for 20 of these feet demonstrating a statistically significant improvement in all FAOS, FADI and EQ-5D-5L domains (p < 0.05). The implant removal rate for persistent sinus tarsi pain was 48.1% (n = 102). Conclusion: Use of a subtalar arthroereisis implant as an adjunct to conventional procedures in stage 1 flexible PCFD can result in significant improvement in pain and function. Patients should be counselled as to the relatively frequent rate of subsequent implant removal.

Introduction and objective: Subtalar arthroereisis is a procedure commonly performed in children with flat feet. The procedure is performed when conservative treatment did not have the desired effect,or when the patient’s abnormal symptoms are very severe and make it difficult for them to function normally in daily life. The aim of this study was to assess whether subtalar arthroereisis and physiotherapy improve the quality of life among children with flat feet. Material and methods: The study comprised 79 patients (140 operated feet) diagnosed with a flat foot defect who underwent a subtalar arthroereisis procedure. A self-administered questionnaire and a shortened version of the standardised WHOQOL-BREF questionnaire were used in the research. Results: The study confirmed that the patients’ quality of life after surgery was high in all the areas regarding the somatic, psychological, social and environmental domains. In the group of children assessed 13–24 months after surgery. it was also found that rapid fatigue after exercise (30% ± 9%) and Achilles tendon contracture (7% ± 4%) were significantly reduced. The results of the study confirmed that subtalar arthroereisis contributes to a decreased demand for orthoses in children (9% ± 6%) and for orthopaedic footwear (11% ± 5%) than before surgery. Conclusions: The employment of subtalars arthroereisis has a positive effect on the quality of life of children with flat feet. The surgery contributes to a reduction in pain and other abnormal symptoms that are associated with flat feet. In addition, physiotherapy performed after the procedure had a positive effect on the healing process and contributed to the improvement of the children’s quality of life.

Introduction: Pediatric idiopathic pes planovalgus can correct itself with growth. Otherwise, in the event of functional impairment and after failed conservative treatment, surgery can be considered. Based on a multicenter retrospective study, we report the functional and radiographic results obtained after subtalar arthroereisis. Hypothesis: We hypothesized that this surgery improves functional and radiological parameters in childhood. Material and method: Forty-eight medical records of children (78 feet) operated on between 2010 and 2019 were studied. Functional (FAOS score) and radiographic (Djian angle, calcaneal slope, lateral talocalcaneal divergence and calcaneus/M5 alignment, talonavicular coverage measurement, AP talocalcaneal divergence) results were studied. The analysis of these different criteria was carried out between the preoperative period and the last follow-up. Results: The functional outcome was satisfactory with an average FAOS questionnaire score of 95.5 out of 100 total points. All the radiographic parameters studied were significantly improved (p<0.001). The average age at the time of surgery was 11.3 years (range: 7 to 16) with a mean follow-up of 35 months (range: 18 months to 84). Spontaneous screw expulsion and subtalar pain were the main complications found. Discussion: The results obtained are consistent with those in the literature. The age at the time of the surgery is an essential factor to consider with the goal of optimal correction. Conclusion: This technique is reliable and effective in the short term. It can be offered as first-line therapy in the management of symptomatic pes planovalgus in children. The follow-up is short, which necessitates longer term studies of this population. The ideal age for surgery remains to be determined.

Introduction: Although pes planus, a common deformity in children with cerebral palsy (CP), is predominantly treated through lateral column lengthening (LCL), subtalar arthroereisis (SA) has also gained popularity for this purpose. This systematic review was conducted to compare surgical outcomes between LCL and SA for pes planovalgus in children with CP. Methods: PubMed, EMBASE, Cochrane Library, and Google Scholar were comprehensively searched for relevant articles reporting the outcomes of LCL and SA in the target population. Surgical outcomes were evaluated in terms of radiographic parameters and postoperative complications. Results: This review included 22 studies involving patients undergoing LCL (LCL group) and 9 studies involving those undergoing SA (SA group). LCL outperformed SA in terms of corrections in the talonavicular coverage angle (8.1°-42.1° vs. 8.0°-30.7°), anteroposterior talo-first metatarsal angle (12.3°-33.7° vs. 9.8°-21.4°), and calcaneal pitch angle (2.5°-29.7° vs. 3.5°-8.0°). Furthermore, the risk of postoperative complications, such as recurrence, pain, undercorrection, and overcorrection, was higher in the LCL group than in the SA group. However, the risks of reoperation and implant-related problems were higher in the SA group than in the LCL group. A meta-analysis of two randomized studies revealed that improvement in calcaneal pitch angle was significantly greater in the LCL group than in the SA group (mean difference: 2.09°; P = 0.0488). Conclusion: LCL outperforms SA in correcting pes planus-related radiographic parameters in patients with CP. However, postoperative complications appear to be more common after LCL than after SA.

Background: Flexible flatfoot is a normal finding in infants and the arch is shaped spontaneously in most children before the age of 10 years. Flexible flatfoot is a common deformity in both adolescent and adult populations. Objective: This prospective study aims to assess the functional and radiological outcomes of subtalar arthroereisis in adolescent patients with symptomatic flexible flatfoot. Methods: This is a prospective study and included 26 feet in 19 patients who underwent subtalar arthroereisis for symptomatic flexible flatfeet deformity. Preoperative and postoperative functional assessment based on the American Orthopedic Foot and Ankle Society (AOFAS) hindfoot scale. Radiographic parameters included preoperative and postoperative Kite`s angle, talonavicular coverage angle, Anterior-Posterior talo-1st metatarsal angle, Meary`s angle, talar declination angle, calcaneal inclination angle and lateral talocalcaneal angle. Results: The mean follow-up period was 22.5±9.4 months and the mean preoperative AOFAS score was 54.6±6.0, while the mean AOFAS score at the last follow-up visit was 86.3±3.9 (P<0.001).The mean preoperative and postoperative radiological measurements were 19.0°±8.2° and 7.4°±3.9° for the AP Talo-1st metatarsal angle (P<0.001); 23.6°±9.1° and 8.0°±4.0° for talonavicular coverage angle (P<0.001); 35.4°±3.7° and 24.1°±3.4° for Kite`s angle (P<0.003); 22.4°±6.1° and 7.5°±3.7° for Meary`s angle (P<0.001); 41.0°±4.4° and 25.2°±7.1° for talar declination angle (P<0.001); 13.5°±3.7° and 21.3°±3.6° for calcaneal inclination angle (P<0.001) and 52.4°±7.2° and 42.9°±4.8° for lateral talocalcaneal angle (P<0.041) respectively. Conclusion: Subtalar arthroereisis is an effective and minimally invasive procedure that showed clinical and radiological improvement for symptomatic flexible flatfoot in our study group.

Introduction: Paediatric flexible flatfoot (PFFF) is a common, potentially debilitating condition affecting a significant proportion of active children. Despite its prevalence, there is a lack of consensus on optimal operative management in symptomatic children. We report a unique case series of six feet treated with the Arthrex ProStop Subtalar Arthroeresis Screw (Arthrex, UK) in the North West of England. Methods: Following a comprehensive review of available literature, we performed a retrospective study of six feet (four patients, aged 11-15 years, including one female and one male with bilateral disease) managed with the Arthrex ProStop Subtalar Arthroeresis Screw from 2019 to 2023. Radiographic and clinical findings pre- and post-operatively were compared with a two-year follow-up. Results: Post-operative radiographs demonstrated an increase in calcaneal pitch, an average of a 17.6° improvement in Meary's angles and a reduction in talonavicular joint uncoverage. Clinical improvement was seen in both stance and heel valgus. The intervention resulted in improved patient satisfaction in all. In this series, there were no infections. However, one implant was removed at 14 months due to persistent pain. All remaining screws were removed at two years due to a lack of research into the long-term outcomes of the device in paediatric patients. Conclusions: This study highlights that subtalar arthroereisis is an effective surgical management option for treating PFFF in adolescents, with limited available literature. Further, large-scale comparative studies with long-term follow-up are required to delineate the true benefit of this procedure.

Background: Idiopathic flexible flatfoot is a common condition in children which typically improves with age and remains asymptomatic. However, the condition can sometimes be more severe, and cause mechanical impairment or pain. The aim of the study was to perform a prospective clinical, radiological, podoscopic and pedobarographic assessment (static and dynamic) of subtalar titanium screw arthroereisis for the treatment of symptomatic, idiopathic, flexible flatfeet. Methods: A prospective, consecutive, non-controlled, cohort, clinical follow-up study was performed. In total, 30 patients (41 feet), mean age 10 (6 to 16 years), were evaluated. Clinical and standing radiological assessments, static and dynamic pedobarography, as well as podoscopy, were performed before surgery and at final follow-up. Results: Treatment was associated with significant improvements in heel valgus angle, radiographic parameters (lateral and dorso-planar talo-first metatarsal angle, calcaneal inclination angle, talar declination angle, longitudinal arch angle) and podoscopic parameters (Clark's angle, Staheli's arch index and Chippaux-Smirak index). Significant increases were noted for lateral loading, forefoot contact phase and double support / swing phase, and reduced medial loading (dynamic pedobarography), as well as lateral midfoot area and loading, but decreased were observed for medial forefoot loading (static pedobarography). Four patients reported persistent pain in the sinus tarsi region (six feet), and in one case, the implant was replaced for a larger one due to undercorrection. No overcorrections or infection complications were noted in the study group. Conclusions: Subtalar arthroereisis is a minimally-invasive and effective surgical method for treating symptomatic, idiopathic, flexible flatfeet; it has an acceptable complication rate with good early clinical results.

Collapsing foot deformity (CFD) and its resulting sequelae caused by recurring talotarsal joint dislocation (RTTJD) affects pediatric and adult patients. An extraosseous talotarsal stabilization (EOTTS) procedure, a subset of subtalar arthroereisis (SA) procedures, is recommended as a minimally invasive, first in-line surgical treatment option for CFD. The aim of this multicenter, retrospective study was to evaluate patient-reported outcomes measures in patients who were treated for RTTJD with Type II EOTTS implants. Sixty-seven cases having a median age of 38 years (range: 10-74) with more than 5 years of follow-up were included in this study. The mean postoperative visual analog scale and Maryland Foot Score was 1.0 ± 1.9 and 92.3 ± 11.3, respectively, indicating excellent clinical outcomes. Subjectively, 88% cases reported as being satisfied with the outcome, 94% cases said they would recommend EOTTS, and 93% said that, if necessary, they would repeat it on their contralateral foot. A subgroup analysis revealed that while not statistically significant, clinical outcomes were slightly better in pediatric patients compared to adults. Implant removal rate was 4.5% (3 cases), and these were in the adult group only. Rate of minor issues such as pain, stiffness, discomfort, etc. was 15%; however, no serious adverse effects or complications were observed in any patient. This study suggests that EOTTS is an effective surgical treatment option wherein successful long-term clinical outcomes with low failure rates can be achieved in a select patient population.

Background: This study analyzed the advantages and disadvantages of different procedures for stage IIA progressive collapsing foot deformity (PCFD) through three-dimensional finite element models. Methods: A previous validated stage IIA PCFD FEA model was established consisting of 16 bones, 56 ligaments, 5 muscles and soft tissues. The ligament properties of the spring, deltoid, short plantar and long plantar ligaments, and plantar fascia were attenuated according to a previous publication. Medial column fusion (MCF), medializing calcaneal osteotomy (MCO), lateral column lengthening (LCL), and subtalar joint arthroereisis (SJA) operations were simulated in this model. The indexes of plantar stress distribution, maximum von Mises of the medial and lateral columns, strain of the medial ligaments and plantar fascia that supported the medial longitudinal arch, arch height, talo-first metatarsal angle, calcaneus pitch angle, and talonavicular coverage angle were all compared before and after simulated single-foot weight loading. Results: The maximum plantar stress of PCFD decreased with MCO and SJA but increased with MCF and LCL. MCF and LCL failed to significantly reduce the stress on the medial column fragments, thereby increasing their stress. Both MCO and SJA relieved medial plantar stress. MCF had no significant effect on stress relief of the medial ligament. MCO, LCL, and SJA were all shown to reduce the pressure on the medial plantar ligament, with LCL having the most obvious effect. All four procedures corrected the arch deformity; however, MCF was not as effective as the other methods. SJA is the best method for restoring arch height and correcting arch deformities. For stage IIA PCFD, isolated MCF failed to reduce pressure on the medial column; however, isolated MCO significantly reduced the pressure on the medial plantar and ligamentous soft tissues while restoring the foot's arch and correcting the hindfoot valgus. Conclusion: SJA with type II sinus tarsi implant effectively transferred pressure from the medial plantar tract to the lateral side and restored the arch. Isolated LCL was not found suitable for stage IIA PCFD.

Purpose: To investigate the clinical efficacy of modified kidner procedure combined with subtalar arthroereisis in the treatment of adolescent type II painful accessory navicular with flexible flatfoot.Methods: From January 2018 to January 2022, 25 adolescent patients (40 feet) with painful type II accessory navicular and flexible flatfoot admitted to our hospital were enrolled in the study, including 13 males (23 feet) and 12 females (17 feet). All patients underwent modified kidner procedure combined with subtalar joint arthrodesis. The Meary's Angle, the first metatarsal Angle of talus (APTMT), the second metatarsal Angle of talus, Pitch Angle, talus tilt Angle, talonavicular coverage Angle (TCA), talus calcaneal Angle (LTCA), and calcaneal Angle were measured on weight-bearing anteroposterior and lateral x-ray films before operation and at last follow-up. The American Orthopaedic Foot and Ankle Society (AOFAS) midfoot score and visual analogue scale (VAS) were used to evaluate the improvement of foot function and pain.Results: All patients were followed up for average 17.4 ± 2.6 months (12–24). The incisions of 25 patients healed by first intention. The weight-bearing anteroposterior and lateral x-ray films of the foot showed that the suture anchors did not pull out or break, and the foot arch did not collapse further. There was no screw withdrawal or secondary operation to remove the screw in all patients. At the last follow-up, the postoperative visual analogue scale (VAS) score of the affected foot was significantly lower than that before operation (P < 0.01), and the American Orthopaedic Foot and Ankle Society (AOFAS) foot function score was significantly higher than that before operation (P < 0.01). At the last follow-up, the weight-bearing anteroposterior and lateral foot x-ray films showed that: The Meary's Angle, the first metatarsal Angle of the talus (APTMT), the second metatarsal Angle of the talus, Pitch Angle, talar tilt Angle, talonavicular overbite Angle (TCA), talocalcaneal Angle (LTCA), and calcaneal Angle significantly improved when compared with those before operation (P < 0.01).Conclusions: The modified kidner procedure combined with subtalar arthroereisis has a good clinical effect in the treatment of adolescent type II painful accessory navicular with flexible flatfoot, which can effectively improve the pain symptoms, improve the foot function and imaging manifestations, and correct the flatfoot deformity.

Background: Kidner procedure is thought to be able to eliminate the medial foot pain and contribute to restoring the medial longitudinal foot arch, making it particularly suitable for surgical treatment of pes planus that combined with symptomatic type 2 accessory navicular (AN). However, controversy remains, and the clinical evidence is still lacking. The aim of the current study is to verify the necessity of Kidner procedure during subtalar arthroereisis (STA) for pediatric flexible flatfoot (PFF) that combined with symptomatic type 2 AN. Methods: Forty pediatric patients (72 feet) who had undergone STA for flexible flatfoot and were also diagnosed with symptomatic type 2 AN concomitantly were reviewed retrospectively and divided into two groups (STA + Kidner vs STA alone). The visual analog scale (VAS), the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale, the Oxford ankle foot questionnaire for children (OAFQC), and the radiographic parameters that quantifying pes planus were evaluated as primary outcomes. Secondary outcomes included the incidence of complications. Results: There were 35 feet in the STA + Kidner group and 37 feet in the STA alone group, with mean follow-up periods of 2.7 years and 2.1 years, respectively. The VAS, AOFAS, OAFQC scores and radiographic parameters presented no significant difference between the two groups both preoperatively and at final follow-up (P > 0.05 for each). The complications of STA surgery occurred equally in both groups, and Kidner procedure could lead to more incision problems (22.9% vs. 2.7%) and a longer time to return to activity. Conclusion: Kidner procedure may be unnecessary during surgical treatment of PFF that combined with painful type 2 AN. Correcting the PFF while leaving the AN alone has a high possibility of relieving the pain in the AN region, and tibialis posterior tendon (TPT) rerouting hardly aids in reconstruction of the medial foot arch.

Background: Subtalar arthroereisis (STA) has gained growing acceptance as a viable approach solution for the management of pediatric flexible flatfoot. However, STA still remains controversial. The purpose of this study is to assess the effect of STA using the Talar-Fit implant for treating pediatric flexible flatfoot. Specifically, the aims of the study are as follows: first, to present the mid-term outcomes of STA using the Talar-Fit implant; second, to compare the radiographic and clinical outcomes associated with varying sizes of Talar-Fit implant; and third, to analyze the optimal position of the inserted implants.Methods: A retrospective analysis was conducted on a cohort of 57 pediatric patients diagnosed with flexible flatfoot (77 feet) who underwent STA utilizing Talar-Fit between January 2014 and December 2021. The participants were categorized into five groups according to the size of the implant: Group 8, Group 9, Group 10, Group 11, and Group 12. The evaluation included the assessment of clinical function using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle–hind foot score, as well as the assessment of radiographic data such as the calcaneal pitch angle (CPA), lateral Meary angle (LMA), talar declination angle (TDA), and medial longitudinal arch angle (MLAA) were evaluated. Furthermore, the position of the inserted implants was also recorded, including angle, depth, and distance. The comparison of pre- and postoperation was conducted using the paired Student's t-test, whereas the analysis of differences among subgroups was performed using the Wilcoxon rank-sum test. A P-value < 0.05 is considered statistically significant.Results: In total, 57 pediatric patients (77 feet) were successfully followed-up for an average period of 26.8 months. The overall AOFAS score significantly improved from 58.6 ± 10.9 to 85.2 ± 8.6 (P < 0.001). Furthermore, the LMA decreased from 20.3° ± 3.6° to 4.5° ± 1.3°, the CPA increased from 14.8° ± 1.6° to 23.6° ± 2.7°(P < 0.05), the TDA decreased from 40.2° ± 2.3° to 25.5° ± 3.2°(P < 0.05), and the MLAA decreased from 140.1° ± 2.8° to 121.4° ± 3.9°(P < 0.05). No statistically significant differences were observed among subgroups regarding the final outcomes. The improvements of CPA, TDA, and MLAA among different groups were significantly different; however, the adjusted P-values were all greater than 0.05. The implant were inserted at a mean angle of 89.5° ± 2.4°, a mean depth of 0.9 mm ± 2.1 mm, and a mean distance of 9.9 mm ± 0.9 mm. Eight patients experienced complications, including six cases of pain occurrence and two cases of implant dislocation.Conclusion: STA with Talar-Fit has demonstrated satisfactory mid-term outcomes. A Talar-Fit with a larger size may demonstrate a superior effect when compared with that of a smaller size. The implants were inserted in a similar position, indicating that the medial edge of the implant may be possible to transcend the midline of the talus neck.

Background: The partial dislocation of the talus from the calcaneus and navicular bones is a primary factor leading to a prolonged overpronation during weightbearing. This study aimed to assess the possibility of returning to physical activity and long-term patient satisfaction after an extra-osseous talotarsal stabilization (EOTTS) procedure with a HyProCure sinus tarsi implant for partial talotarsal joint dislocation (TTJ). Methods: A total of 41 adult patients (61 feet), with an average age of 46.41, were included and treated surgically with EOTTS as a stand-alone surgery. Physical activity and functional scores were assessed pre- and post-operatively using questionnaires—the UCLA Activity Score, Symptom-Related Ankle Activity Scale (SAAS), Sports Frequency Score (SFS), Lower Extremity Functional Scale (LEFS), and VAS scale. Satisfaction was assessed on a ten-point scale. The follow-up period was on average 8.61 years (from 7.33 to 10.31). Results: EOTTS had a positive impact on physical activity, and a high rate of patient satisfaction (8.95 ± 1.9) was noted. The treatment led to a reduction in foot pain, as well as an increase in SAAS and LEFS scores (15.6% and 19.3%, respectively, p < 0.01). The VAS pain score decreased by 18.6% (p < 0.001). SFS and UCLA scores showed a small increase, but it was not statistically significant. A positive correlation was noted between patient satisfaction and time of physical activity per week (R = 0.33, p = 0.04), and also between patient satisfaction and SAAS scores (R = 0.43, p = 0.005). Pain from other joints (knee, hip) was eliminated or reduced in 40% of patients after surgery. Conclusions: EOTTS with a HyProCure implant is an effective long-term treatment option for partial talotarsal joint dislocation, leading to a reduction in foot pain and increased patient satisfaction, and allowing for a return to physical activity.

Objectives: To analyze the surgical outcomes of subtalar extra-articular arthroereisis and the patient/parent satisfaction regarding the foot's shape, foot pain, ability to walk, ability to jump, and shoe wear. Methods: Our retrospective cross-sectional study was carried out through an online-based questionnaire to assess patient satisfaction postoperatively at 3 hospitals (King Khalid University Hospital, Sultan bin Abdulaziz Humanitarian City, and Dallah Hospital, Riyadh, Saudi Arabia) between the years 2014-2021. Results: A total of 65 patients participated in our study. Approximately 86.1% of them had the operation bilaterally. The most important aspects where patients noticed the most improvement were the foot's shape (90.8%), pain (81.5%), and ability to walk (76.9%). Conclusion: Several studies have been carried out highlighting the surgical technique and complications of the procedure. However, a limited number of studies have been carried out to assess patient satisfaction with the procedure, especially in Saudi Arabia, as the procedure is considered relatively new in the region with insufficient data regarding it. Therefore, this study is considered one of the few articles regarding subtalar extra-articular arthroereisis in the region.

Purpose Accessory navicular is accompanied by the deformity of valgus flexible flatfoot. The surgical treatment includes reconstruction of insertion of posterior tibial tendon following resection of the accessory navicular. However, this treatment could not correct completely the deformity of valgus flexible flatfoot. This study aimed to evaluate the efficacy of subtalar arthroereisis combined with medial soft tissue reconstruction in treating 8–14-year-old flexible flatfoot patients with accessory navicular. Methods Clinical data of 35 pediatric flatfoot patients (with 50 feet) with accessory navicular who underwent subtalar arthroereisis and medial soft tissue reconstruction between April 2013 and September 2018 were analyzed retrospectively. Anteroposterior, lateral, and hindfoot alignment radiological images were measured in the weight-bearing position, and visual analog scale (VAS), American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale, and satisfaction degree were evaluated. Also, surgical complications were recorded. Results The average follow-up time of the patients was 30 ± 9.3 months. None of the patients presented wound complications, and no implant loosening was detected. The AOFAS and VAS scores improved significantly (P < 0.001). Radiological parameters, such as the talar first metatarsal angle and talonavicular coverage angle on anteroposterior foot view, Meary’s angle and calcaneal pitch angle on the lateral view, and calcaneus valgus angle on hindfoot alignment view improved significantly (P < 0.001). Postoperative complications were observed in three patients. Conclusion Subtalar arthroereisis combined with medial soft tissue reconstruction significantly alleviated pain and improved the functions in pediatric and adolescent flexible flatfoot patients with accessory navicular; also, the radiological manifestations and functions improved.

Aim: Extraosseous talotarsal stabilization (EOTTS) is increasingly popular as a surgical treatment for adult symptomatic flexible pes planus. This can be performed alone or combined with medializing calcaneal osteotomies with or without medial column stabilization. The aim of our radiographic study is to evaluate the changes in various radiographic parameters of a pes planus deformity including hindfoot alignment after EOTTS. We hypothesize that EOTTS can demonstrate improvement in radiographic parameters, including hindfoot alignment. Materials and methods: A total of 12 feet from nine patients who had undergone EOTTS using the HyProCure implant were analyzed. Weight-bearing radiographs were used to measure the pre- and postoperative talar-second metatarsal, lateral Meary’s, calcaneal inclination, talar declination angles. Hindfoot alignment was measured using fibular axis calcaneal offset (FACO) method. Results: Our results showed significant improvement in all the radiographic parameters including hindfoot alignment. Conclusion: There is a radiographic improvement in a flexible pes planus deformity after an EOTTS procedure, including hindfoot alignment. Clinical significance: Hindfoot alignment can be corrected with EOTTS procedure with or without associated procedures.

Arthroereisis is a surgical procedure primarily used to treat flexible pes planus (flatfoot) in pediatric and young adult patients. The principal goal of subtalar arthroereisis is to relieve pain and restore function. This is primarily done by restoring the medial foot arch without fusing the subtalar joint and without requiring a long recovery period needed after osteotomies. Although the procedure can be performed in isolation to treat flexible flatfoot, it can also be performed as an ancillary in the treatment of tarsal coalition, posterior tibial tendon dysfunction, and accessory navicular syndrome. Various implants and multiple surgical techniques exist for arthroereisis, such as the sinus tarsi implant and calcaneo-stop. The type of device and the surgical approach to proceed with are based on the surgeon's discretion rather than an evidence-based protocol. Multiple complications can arise from subtalar arthroereisis, most commonly sinus tarsi pain. Currently, there is a dearth of quality clinical data and evidence on the long-term outcomes and complications of arthroereisis. This lack of literature for a commonly performed procedure validates the need for future studies to better guide a standard protocol, reach consensus on well-defined indications and contraindications, provide expected complications, and improve the practice of evidence-based medicine.

Background: The high success rate, minimal invasion, and safety of subtalar arthroereisis (SA) have made it a primary mode of surgical management for pediatric flexible flatfoot. The HyProCure procedure is a new surgery for SA, However, very few available studies reported the therapeutic effects of the HyProCure procedure, especially in pediatric flexible flatfoot. The main aim of the present study was to investigate the clinical and radiological outcomes of the HyProCure procedure for pediatric flexible flatfoot and analyze the risk factors for therapeutic outcomes and sinus tarsi pain.Methods: In this retrospective cohort study, 69 pediatric flexible flatfoot patients (107 feet) who underwent the HyProCure procedure were included between July 2015 and September 2020. All patients underwent the HyProCure procedure with or without gastrocnemius recession. The Maryland foot score (MFS), visual analog scale (VAS), radiographic data, and complications were assessed at a minimum 1-year follow-up and statistically analyzed.Results: The mean follow-up was 35.9 months (range, 13–73 months). At the last follow-up, VAS (0.64 ± 1.16) was significantly lower than the preoperative VAS (4.06 ± 1.43) (p < 0.001); MFS (90.39 ± 12.10) was significantly higher than the preoperative MFS (71.36 ± 10.25) (p < 0.001). The AP talar-second metatarsal angle (T2MT angle) significantly decreased from 17.0 ± 5.4° preoperatively to 11.4 ± 5.2° at the last follow-up (p < 0.001). The lateral talar-first metatarsal angle (Meary's angle) significantly decreased from 13.8 ± 6.4° preoperatively to 6.3 ± 5.0° at the last follow-up (p < 0.001). The calcaneal declination angle (Pitch angle) significantly increased from 13.5 ± 4.9° preoperatively to 14.8 ± 4.4° at the last follow-up (p < 0.001). Logistic regression analysis indicated that patients with a longer distance from the tail end of the implant exceeding the longitudinal talar bisection line had 275.8% greater odds of MFS < 90. Yet, no risk factors were found in connection with sinus tarsi pain.Conclusions: The HyProCure procedure for pediatric flexible flatfoot achieved satisfactory curative effects with a low complication rate; implant depth was associated with unsatisfactory postoperative outcome.

The aim is to present a single-center case series of patients with symptomatic hyperpronated feet treated with arthroereisis by using a second generation extra-osseous talo-tarsal stabilization device. This case series enrolled 123 feet in 87 patients (20 [6-75] years) treated with arthroereisis, either isolated (76 cases) or combined procedure (47 cases). At their final follow-up, a patient reported questionnaire (overall satisfaction, foot stability and shape, activities of daily living, pain level, and analgesics usage) was distributed. The average postoperative follow-up period was 30 (13-55) months. Nineteen (15%) cases required at least one revision surgery: the implant was manipulated in 5 (4%), while 14 cases (11%) required definitive implant removal. The predominant reason for implant removal was pain (50%), followed by implant migration (27%). The pediatric population with isolated procedure showed lowest revision rate (5%), while adults with combined ankle/hindfoot procedures demonstrated revision rate of 50%. The overall patient satisfaction after arthroereisis was 84%. The patients’ perceived improvement in foot stability was 75%, foot shape 85%, and activities of daily living 64%. Eighty-two percent of cases reported no analgesics usage in the last month and mean visual analogue scale (0-10) pain level decreased from 5.5 to 2.2 (p < .001). The subgroup analyses of patient-reported questionnaires revealed the best outcome in the pediatric-isolated cases, while adults with combined procedures reported the lowermost outcome. Extra-osseous talo-tarsal stabilization demonstrated a low rate of revisions surgery and a high satisfaction rate as an isolated procedure. Patients with conjoined procedures experienced more revisions and considerably lower satisfaction rates.

Background: Our aims were (a) to determine whether subtalar arthroereisis (STA) as adjunct procedure improved radiographic correction of stage IIb adult-acquired flexible flatfoot deformity (AAFD); (b) to assess the STA-related complication rate. Methods: A retrospective analysis of 22 feet (21 patients) diagnosed with stage IIb AAFD treated by medializing calcaneal osteotomy (MCO), flexor digitorum longus (FDL) transfer, spring ligament (SL) repair with or without Cotton osteotomy and with or without STA in a single institution was carried out. Seven measurements were recorded on pre- and postoperative (minimum 24 weeks) radiographs by 2 observers and repeated twice by 1 observer. Inter- and intraobserver reliabilities were assessed. The association of demographic (gender, side, age, body mass index) and surgical variables (Cotton, STA) with radiographic change was tested with univariate analysis followed by a multivariable regression model. Results: Excellent inter- and intraobserver reliabilities were demonstrated for all measurements (intraclass correlation coefficient range, 0.75-0.99). Gender, side, Cotton osteotomy, and STA were included in the multivariable analysis. Regression showed that STA was the only predictor of change in talonavicular coverage angle (TNCA) (R2 = 0.31; P = .03) and in calcaneo-fifth metatarsal angle (CFMA) (R2 = 0.40; P = .02) on dorsoplantar view. STA was associated to a greater change in TNCA by 10.1° and in CFMA by 5°. Four patients out of 12 STA complained of sinus tarsi pain after STA, and removal of the implant resolved symptoms in 3 of them. Conclusion: In this series, STA as an adjunct procedure to MCO, FDL transfer, SL repair in the treatment of stage IIb AAFD led to improvement in correction of forefoot abduction. STA-related complication and removal rates were 33%.

The aim of this retrospective study is to evaluate the clinical-functional and radiographic results in pediatric patients with painful and disabling Flexible Flat Foot (FFF) refractory to conservative treatment who underwent percutaneous subtalar arthroereisis with a Maxwell Brancheau Arthroereisis® (MBA) implant. Patients aged 8-14 years old with a minimum follow-up of 24 months were included. A pre and postoperative radiographic evaluation was carried out analyzing Meary's angle, internal Moreau-Costa-Bartani´s angle, Talar declination angle, Calcaneal Pitch, Kite's angle, Talar-1st metatarsal angle, and Talonavicular coverage angle. In those patients with more than 5 years of follow-up, the development of subtalar osteoarthritis was evaluated. A clinical-functional evaluation was carried out using the American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot rating scale. Pre and postoperative pain was evaluated using the visual analog scale (VAS). Postoperative complications were described. Fourteen patients (19 feet) met the inclusion criteria. The mean age at surgery was 12 years old with a mean follow-up of 68.26 months. All radiographic angles improved significantly. No signs of subtalar osteoarthritis were identified. The mean pre and postoperative pain according to VAS was 7.05 and 0.77 respectively. The mean pre and postoperative AOFAS was 75.42 and 97.05 respectively. One female patient had persistent pain in both feet (VAS = 4). However, she was able to do sports and daily life activities without restrictions. None of the implants needed to be removed due to intolerance or pain. Subtalar arthroereisis seems to be effective to improve the clinical-functional and radiographic parameters in moderate pediatric FFF.

Flexible flatfoot represents one of the most common deformities of the lower limb, affecting children and adolescents. Aesthetic aspect, abnormal gait, pain and fatigue are by far the most important symptoms which determine parents to bring their children to the orthopedist. We set out to conduct a prospective study, case-controlled, including patients with symptomatic flexible flatfeet operated on by arthroereisis surgery and comparing them to a normal feet group of children age- and sex-matched (control group). Minimum follow-up time was 2 years. In total, 33 patients with bilateral arthroereisis were included and 36 patients formed the control group (12.12 +/− 1.85 years vs. 11.81 ± 2.40 years, p = 0.54). Quality of life improved postoperatively (p = 0.18) and was not different from the control group. Median running time improved postoperatively by 2.25 s (p < 0.0001) and got closer to the median running time from the control group (22.30 s compared to 20.94 s, p = 0.01). All radiological angles improved (p < 0.0001), but quality of life improvement was correlated with talonavicular coverage angle and Meary angle measurements. Flatfoot in children and adolescents may be a condition in which the quality of life and sports performance are decreased, compared to healthy children. Arthroereisis is a minimally invasive surgical procedure with a short recovery time and a short period before resumption of sport activities, which can be useful in certain types of flexible flatfoot due to its effectiveness on symptom reduction.

Background Subtalar arthroereisis refers to the implantation of a sinus tarsi implant for the treatment of flexible flatfoot. The purpose of this study was to compare the ability to correct the flatfoot deformity and contact pressure of the posterior subtalar joint between two types of self-locking wedge implants and between two different positions for the same device in a cadaveric flatfoot model. Methods The flatfoot model was created in ten cadaver feet through ligament sectioning and cyclic loading. Three kinds of arthroereisis procedures were evaluated: Talar-Fit (type I self-locking wedge implant) anchored in the sinus portion of the tarsal sinus (T-sinus group), Talar-Fit in the canalis portion (T-canalis group), and HyProCure (type II) in the canalis portion (H group). Corrective ability in the sagittal and transverse planes were measured with clinometers. Contact pressure was measured with pressure-sensitive films. Findings T-canalis group provided more sagittal (mean difference for size 10 mm: 1.9°, P = 0.014; mean difference for size 11 mm: 3.1°, P = 0.037) and transverse (mean difference for size 8 mm: 1.8°, P = 0.049; mean difference for size 11 mm: 2.2°, P = 0.049) corrections than T-sinus group. The flattening process shifted the peak pressure of the posterior subtalar joint to the posteromedial side (P < 0.05) and arthroereisis helped the distribution of contact pressure restore uniformity (all P > 0.05). Interpretation A self-locking wedge implant inserted in the canalis portion of the tarsal sinus achieved better correction than an implant inserted in the sinus portion.

Over the last two decades there is a growing interest in the adult literature for subtalar joint arthroereisis. Parallel to this interest, there have been improvements in the design and biomechanics of the implant, although the main indication of subtalar joint arthroereisis in adults is not clear. Most studies show significant improvement in postoperative clinical scores and visual analog scores. Sinus tarsi pain, being the most common complication, is the main determinant of clinical satisfaction. This review focuses on the role and complications of subtalar joint arthroereisis in the adult population.

Background: Adult acquired flat foot deformity (AAFD) is a spectrum of conditions which can be progressive if untreated. Surgical correction and restoration of anatomical relationship are often required in the treatment of symptomatic Grade II AAFD after a failed course of conservative treatment. There is a paucity of literature recommending best practice-especially in the adult population. The authors aim to compare radiological and clinical outcomes of two widely employed surgical techniques in the treatment of symptomatic AAFD. Methods: A retrospective study of 76 patients with Grade IIB AAFD and had undergone either lateral column lengthening (LCL) or subtalar arthroereisis (STA) surgical correction of their symptomatic AAFD. Each technique was augmented with both bony osteotomy and soft tissue transfer as determined by on table assessment. Clinical and radiological outcomes were reviewed 24 months after surgery. Results: LCL and STA groups had comparable radiological outcomes at 24 months after surgery. However, LCL group demonstrated superior American Orthopaedic Foot and Ankle Society (AOFAS) midfoot (90.3 ± 12.6 vs 81.1 ± 20.6, p < 0.001) as well as Visual Analogue Scale (VAS) midfoot scores (0.5 ± 1.6 vs 1.3 ± 2.4, p < 0.001) at 24 months compared to the STA group. STA had a higher complication rate (20.6% vs 4.4%), with all cases complaining of sinus tarsi pain requiring subsequent removal of implant. Conclusion: There is a role for either techniques in the treatment of symptomatic AAFD. LCL whilst more invasive has demonstrated superior outcome scores and lower complication rates at 24 months compared to STA. Patients need to be counselled appropriately to appreciate the benefits of each technique.

Objectives: To (i) report the mid-term outcomes of subtalar arthroereisis using Talar-Fit implant for the treatment of flexible flatfoot patients; (ii) compare clinical and radiographic outcomes between arthroereisis with and without adjunctive operative procedures to investigate the effects of adjuncts on the outcomes; and (iii) analyze the risk factors associated with sinus tarsi pain, which is the most common postoperative complication of arthroereisis. Methods: Thirty-one flexible flatfoot children and adolescents (46 feet) treated with subtalar arthroereisis using Talar-Fit implant from June 2014 to May 2019 were retrospectively analyzed. The feet were divided into four treatment groups: (i) arthroereisis alone, (ii) arthroereisis with gastrocnemius recession, (iii) arthroereisis with Kidner procedure, and (iv) arthroereisis with gastrocnemius recession and Kidner procedure. Clinical function was evaluated based on the American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score. The following angles were measured for radiographic evaluation: talar-first metatarsal angle, calcaneal pitch angle, and talar declination angle on the lateral view; and talar-first metatarsal angle, talocalcaneal angle, and anteroposterior talonavicular coverage angle on the anteroposterior (AP) view. The paired Student's t-test was used to compare the pre- and postoperative angular measurements and AOFAS scores. The Wilcoxon rank-sum test was undertaken to determine the outcome differences among four treatment groups. Multivariate logistic regression analysis was used to analyze risk factors for sinus tarsi pain. P value <0.05 is considered statistically significant. Results: The mean follow-up of the feet was 32.8 months (range, 10-71 months). The mean AOFAS score significantly improved from 55.5 ± 14.5 preoperatively to 86.3 ± 9.9 (P < 0.001). Comparison of radiographic outcomes showed that the lateral talar-first metatarsal angle decreased by a mean of 19.1° ± 11.9° (P < 0.001), the calcaneal pitch angle increased by a mean of 5.4° ± 3.4° (P < 0.001), the talar declination angle decreased by a mean of 14.8° ± 9.9° (P < 0.001), the AP talar-first metatarsal angle decreased by a mean of 15.6° ± 10.3° (P < 0.001), the AP talocalcaneal angle decreased by a mean of 7.2° ± 8.3° (P = 0.001), and the AP talonavicular coverage angle decreased by a mean of 20.4° ± 9.0° (P < 0.001). There were no statistically significant differences with regard to AOFAS score and all angle measurements on both the AP and lateral views among the four treatment groups. There was one dislocation case caused by a fall 6 weeks after surgery, which was treated nonoperatively. The incidence of sinus tarsi pain was 13% and logistic regression analysis indicated that patients with a longer distance from the tail end of the implant to the lateral calcaneal wall had 38.8% greater odds of developing sinus tarsi pain. Conclusions: The mid-term clinical and radiographic results were satisfactory in patients who underwent the subtalar arthroereisis procedure using Talar-Fit implant, alone or in combination with other adjuncts, for the treatment of flexible flatfoot.

In this retrospective study, we aim to assess the safety and feasibility of adapting subtalar arthroereisis (SA) for type I osteogenesis imperfecta (OI) patients with symptomatic flatfoot. From December 2013 to January 2018, six type I OI patients (five girls and one boy, 12 feet) with symptomatic flexible flatfoot were treated with SA and the Vulpius procedure. All the patients were ambulatory and skeletally immature with failed conservative treatment and unsatisfactory life quality. The median age at the time of surgery was 10 years (range 5-11), and the median follow-up period was 55 months (range 33-83). All functional and radiographic parameters improved (p < 0.05) after the procedure at the latest follow-up. The median American Orthopaedic Foot and Ankle Society ankle-hindfoot scale improved from 68 (range 38-80) to 95 (range 71-97). All of the patients ambulated well without significant complications. The weight-bearing radiographs showed maintained correction of the tarsal bone alignment with intact bony surfaces adjacent to implants during the post-operative follow-up period. This is the very first study on symptomatic flatfoot in pediatric patients with type I OI. Our data suggest that SA is a potentially viable approach, as functional improvements and maintained radiographic correction without significant complication were observed.

Subtalar arthroereises (STA) is a minimally invasive and reversible surgery to correct symptomatic flexible flatfoot (FFF) in children. Various techniques were described either applying expandable sinus tarsi implants or lateral calcaneus stop screws. Studies comparing the outcome of STA with different devices are rare. This retrospective single-center cohort study analyzes the results of STA using three different implants. 113 STA were performed in 73 consecutive patients (28 females). Mean age at surgery was 10.8 years (range 5-16). Mean follow-up was 29.0 months (range 1-111). In 21 feet the non-absorbable Kalix® endorthesis and in 56 feet the absorbable Giannini endorthesis were applied. Subtalar extraarticular screw arthroereises (SESA) was conducted in 36 feet. Clinical, radiographic and pedobarographic parameters were analyzed. No intraoperative complications were observed. All three procedures achieved comparable improvements of the clinical, radiographic and pedobarographic parameters. The mean foot function index (FFI) improved from 36.4 (range 12-63) to 22.8 (range 2-55). The mean preoperative calcaneal inclination angle and the lateral talocalcaneal angle improved from 9.5° (range 0-22) and 42.3° (range 21-62) to 12.8° (range 0-26) and 37.6° (range 15-56), respectively. Pedobarographically determined values of the arch index, the medial midfoot contact area and the medial forefoot peak pressure decreased. In contrast to SESA (1/36, 3%), a higher incidence of implant-related complications was observed using Kalix® (6/21, 29%) and Giannini (10/56, 8%) sinus tarsi implants. Peroneal muscle contractures only occurred in the SESA group (4/36, 11%). Premature removal due to treatment-related complications was necessary in 6/21 Kalix® implants (29%), 4/56 Giannini implants (7%) and 4/36 SESA implants (11%). Implant choice for treatment of painful FFF in children with STA seems to play a subordinate role. Clinical, radiographic and pedobarographic outcomes are comparable between the applied implants. Surgeons and patients should be aware of the different spectrum of implant-related complications. Treatment can be reliably monitored by radiation-free pedobarography providing dynamic information about the deformity.

Background: The aim of this prospective nonrandomized case series study was to assess the intermediateterm outcomes of extraosseous talotarsal stabilization (EOTTS) combined with Achilles tendon lengthening for correction of flexible planovalgus foot deformity in children with cerebral palsy. Methods: A total of 20 skeletally immature feet of 9 boys and 5 girls aged 7 to 15 years old (average 10.8 years), with Level I and II CP (according to the Gross Motor Function Classification System) and, were treated via EOTTS and Gastrocnemius recession or Achilles tendon lengthening. Six of them had diparetic and eight hemiparetic. The average follow-up time was 27.3 months (12 to 42 months). Preoperative and postoperative American Orthopedic Foot and Ankle Society-Ankle and Hindfoot (AOFAS-AH) scores, dorsoplantar talar second metatarsal angles (T2M), and lateral talar declination angles (TD) of the affected foot were recorded. Results: Correction of the preoperative talar alignment deformity was normalized in all patients. The average TDA improved from 30.06° ± 2.74° preoperatively to 20.76° ± 2.3° postoperatively. The mean T2MA improved from 39.06° ± 2.05° preoperatively to 15.92° ± 3.12° postoperatively. The AOFAS-AH score also improved from 62.8 ± 1.74 preoperatively to 87.8 ± 2.13 at the final follow-up. Conclusion: EOTTS and associated soft tissue procedures reliably corrected the hindfoot deformity and have shown to be a good treatment option in the treatment of flexible planovalgus feet in children with Level I and II CP

Background: Subtalar arthroereisis may cause sinus tarsi pain complications. In this study, we aimed to introduce a customised implant that facilitated treatment effect and less impingement. The biomechanical outcome between the intact and implant conditions was compared using finite element analysis. Methods: A female patient with flatfoot (age: 36 years, height: 156 ​cm, body mass: 51 ​kg) was recruited as the model patient. The customised implant was designed from the extracted geometry. Boundary and loading conditions were assumed from the data of a normal participant. Four gait instants, including the ground reaction force first peak (25% stance), valley (45%), initial push-off (60%) and second peak (75%) were analyzed. Results: The navicular height was elevated by 4.2% at 25% stance, whereas the strain of the spring, plantar cuneonavicular and plantar cuboideonavicular ligaments were reduced. The talonavicular joint force decreased and the calcaneocuboid joint increased by half and 67%, respectively, representing a lateralised load pathway. There was a stress concentration at the sulcus tali reaching 15.29 ​MPa. Conclusion: Subtalar arthroereisis using a customised implant may produce some positive treatment effects in terms of navicular height elevation, ligament strain relief and lateralised joint loading pathway. Although the concentrated stress at the sulcus tali did not exceed the threshold of bone breakdown, we could not rule out the potential of vascular disturbance owing to the remarkable elevation of stress. Future study may enlarge the contact area of the bone-implant interface by considering customisation based on the dynamic change of the sinus tarsi during walking gait. The translational potential of this article: Geometry mismatch of prefabricated implants could be the reason for complications. With the advancement of 3D printing, customising implant becomes possible and may improve treatment outcome. This study implemented a theoretical model approach to explore its potential under a simulation of walking.

Ulcerations under the medial column in patients with acquired neuropathic pes planus may be intractable to conservative techniques such as regular debridement, offloading, bracing, and accommodative shoes. When surgery becomes necessary for these patients, the foot and ankle surgeon has the option of exostectomy, medial column beaming, medial column fusion, and external fixation, among others. In the case of a flexible midfoot collapse, the option of arthroereisis for indirect medial column support may be warranted. In this preliminary report, the authors detail a technique of Achilles tendon lengthening, arthroereisis implantation, and advanced cellular tissue product application in an attempt at wound coverage and prevention of recurrence. Three patients presenting with intractable medial column ulcerations of ∼1 year's duration underwent this procedure, and within 7 weeks (range 5 to 7), all medial column ulcerations healed. These patients remained healed at last follow-up (average 29 months; range 8 to 44). This preliminary report provides evidence for a minimally invasive procedure aimed at offloading, healing, and preventing recurrence of medial column ulcerations in patients with flexible neuropathic pes planus.

Implant extrusion in subtalar arthroereisis is a common complication for pediatric flexible flatfoot. However, there were a limited number of articles addressing the body weight effects on implant extrusion after the procedure. We conducted a 24-month follow-up assessment after subtalar arthroereisis. Surgical patients who underwent the Vulpius procedure were retrospectively collected from May 2010 to January 2017, including 59 cases of both feet having implants in situ and 43 cases of both feet having implant extrusion. The average age of 102 patients was 9 years old. The mean body mass index (BMI) of the implant in situ group was 19.5, whilst the extrusion group was 21.2 (p = 0.035). The inter-observer correlation was excellent. There were 11 cases (39.3%) of bilateral extrusion in the overweight group (BMI ≥ 24) and 13 cases (23.2%) in the low body weight group (BMI ≤ 18.5) (p < 0.0004). Postoperative radiographic angles were corrected in both the implant in situ group and the extrusion group. Nonetheless, the implant in situ group revealed better postoperative outcomes of Meary’s angle and the talonavicular angle from an anterior-posterior view, and the talar inclination angle from a lateral view. We conclude that a higher BMI is related to implant extrusion and worse results after subtalar arthroereisis. Further prospective study to investigate whether preoperative weight loss results in improved surgical outcomes is warranted in the future.

Introduction: Flexible flatfoot (FFF) is one of the most common skeletal disorders in children. In symptomatic patients who do not respond to conservative measures, surgery may be an option. Subtalar arthroereisis consists of limiting excessive eversion of the subtalar joint through different types of implants. Materials and methods: We carried out a retrospective study of 16 patients (32 feet) intervened for FFF with a subtalar device (arthroereisis), across the period of 2008-2015 with a minimum follow-up period of one year. Pre- and postoperative measures of the Moreau-Costa-Bartani angle, dorsoplantar (DP) and lateral (L) talocalcaneal angle, talonavicular coverage angle, and naviculocuboid overlap were used to evaluate correction of the deformity. Two expert surgeons from the Pediatric Orthopedics Unit took separate measurements of these angles for subsequent analysis purposes and to obtain the interobserver correlation coefficient for quantitative variables. Pre- and postoperative differences in the measurement of angles were ascertained using Student's t-test for paired samples; and a functional evaluation of the patients intervened was carried out pre- and postoperatively by administering the parent version of the Oxford Ankle Foot Questionnaire for Children (OxAFQ-C) during a clinical interview. All statistical analyses were performed using the SPSS v. 19.0 program (SPSS, Chicago, IL), with values being deemed statistically significant at p<0.05. Results: A breakdown of the study population showed 81.25% (13 patients) males and 18.75% (3 patients) females, with mean age of 9 years (7-11). The interobserver coefficient for quantitative variables displayed a very high degree of concordance (0.7-0.9), indicating that the validity of the measures was adequate. Pre- and postoperative analysis of differences in the measurement of angles was statistically significant (p<0.005). In terms of functional evaluation, the postoperative results were positive, with statistical significance for the "school and play", "emotional", and "footwear" domains of the OxAFQ-C scale and no differences in the "physical" domain. Conclusion: Subtalar arthroereisis is a valid option for the treatment of symptomatic pediatric flatfoot, with good postoperative functional and radiographic results.

Background: The use of an arthroereisis implant for the treatment of adolescent flatfoot deformity has been described. However, data that address the outcomes of patients treated with an arthroereisis implant in adults are limited. The purpose of this study was to investigate the radiographic and clinical outcomes and complications following the use of a subtalar arthroereisis implant as an adjunct for correction acquired flatfoot deformity secondary to posterior tibial tendon dysfunction. Methods: A retrospective case-control study was performed querying all patients undergoing surgical flatfoot correction between January 1, 2010 and January 1, 2015. The experimental group included patients undergoing arthroereisis augmentation at the time of flatfoot correction. Patients undergoing the same flatfoot correction without the use of an arthroereisis implant were used as controls. Radiographic measurements were evaluated preoperatively and at final radiographic follow-up and included talonavicular (TN) coverage angle, and lateral talar-first metatarsal angle (T1MA). Patient-reported outcomes were assessed using preoperative visual analog scale (VAS) pain scores and postoperative Short Form-36, VAS, and satisfaction at final orthopedic follow-up. Results: A total of 15 patients underwent flatfoot correction and were augmented with an arthroereisis implant and were matched with 30 controls. Postoperative, mid-term T1MA and regional analysis was found to be improved in the experimental group versus control. Patients undergoing adjunct subtalar arthroereisis demonstrated an increased likelihood of achieving radiographically normal talonavicular coverage <7° compared with our control group at follow-up. Conclusions: The adjunct use of an arthroereisis implant resulted in improved and maintained radiographic and clinical measurements in patients undergoing stage II flatfoot. Clinical significance: These results suggest utility of a subtalar arthroereisis implant as an adjunct to flatfoot correction with little additional risk of harm to the patient.

Background Excessive hindfoot pronation, talotarsal joint (TTJ) instability, has been attributed to an increase in medial knee compartment pathology. Advocacy for hindfoot realignment has been the subject of research. An internal solution for TTJ instability, extra-osseous talotarsal stabilization (EOTTS), exists but its effect on knee forces is unknown. This is the first study to measure the in vivo forces acting within the medial knee compartment before and after EOTTS. We hypothesized that following EOTTS there should be a reduction of force acting on the medial knee compartment. Methods 10 fresh frozen cadaver lower extremities exhibiting clinical and radiographic evidence of TTJ instability were evaluated. The proximal femur segment was mounted to a mechanical testing unit. Pressure sensors were placed within the medial knee compartment. A force of 1000 newtons was then applied, and the femur was internally rotated 10 degrees. Measurements were recorded before and after the insertion of a type II EOTTS stent. Results Pre-EOTTS resulted in an average of 842 ± 247N acting within the medial knee joint compartment. These forces then decreased to an average of 565 ± 260N (<0.05) following EOTTS, representing an average reduction of force by 32.8%. Conclusion EOTTS has been shown to decrease the in vivo forces action within the medial knee compartment. This helps to further illustrate the importance of realigning and stabilizing the hindfoot for the prevention and treatment of chronic knee pain.

Background: The aim of the study was to evaluate the clinical and radiological results obtained in the treatment of adult flexible flatfoot secondary to posterior tibial dysfunction with subtalar arthroereisis using a Kalix ® endorthesis. Methods: 35 patients (37 feet) were studied, having been operated between January 2010 and January 2015 for reducible flatfoot secondary to posterior tibial tendon dysfunction stage IIA1 of Bluman. Results: The average follow up was 47.52 months with a minimum of 14 months and a maximum of 75 months. The average age was 54.85, with an age range from 40 to 80 years old. In 74% of cases excellent or good results were obtained, according to our evaluation. The most common complication of this procedure was persistent pain in the sinus tarsi. 35% of cases in this group required implant removal for this reason. Conclusions: We believe that arthroereisis is valid for the treatment of flat foot secondary to posterior tibial tendon dysfunction at this stage, giving a high percentage of good and excellent results.

The aim of this study was to establish whether children treated with subtalar arthroereisis for flexible flatfoot were able to return to sport activities. We reviewed 49 patients with a mean age at the time of surgery of 10.7 years. The type of sport activities, the number of sessions per week, the time dedicated to each session, and the level achieved were assessed preoperatively and at the last follow-up. Overall, 45 patients returned to sports after surgery. Surgery did not alter the duration, frequency, and type of sporting activities, but the participation in physical activities as well as the emotional status and footwear issues improved.

Subtalar arthroereisis has been proved to be an efficient method for correcting flexible adult flatfoot. However, the optimal sinus tarsi implant is still debated and yet to be determined. In the present study, we compared the biomechanical effects of type I and II sinus tarsi implants in stage II adult-acquired flatfoot deformity (AAFD). First, a finite element model of stage II AAFD was established in which virtual surgery of subtalar arthroereisis was simulated. The indexes of plantar stress distribution, peak von Mises of the medial and lateral columns, strain of the medial ligaments and plantar fascia, arch height, talo-first metatarsal angle, calcaneus pitch angle, talonavicular coverage angle, and hindfoot valgus angle were all compared and analyzed. The results of the present study have validated the stage II AAFD finite element model by comparing the simulation results with the same parameters measured from weightbearing radiographs in the midstance phase. All the indexes showed that both types of arthroereisis can lower the plantar pressure and the strain of the medial ligaments that support the medial longitudinal arch and can shift the load of the medial column to the lateral column. They can also help to correct the deformity and restore the arch. However, the type II sinus tarsi implant design exhibited a more obvious effect than that of type I.

The author retrospectively analyzes the results of 250 ankle arthroeresis operations performed on 178 patients at Klaipėda University Hospital from 2009.12.04 to 2015.02.28. Almost all operations were performed by the author of the article himself, using the same methodology and the same stent (HyProCure, Gramedica, USA). Unlike other studies published on this topic, the operated patients belonged to various age groups from 5 to 77 years. The indication for the operation was flatfoot caused by ankle instability, manifested by heel hyperpronation and being the cause of other accompanying complaints and foot deformities. During the reviewed 5-year period, 21 stents, which accounted for 8.1%, had to be removed for various reasons. Half of them were removed due to subjective complaints of pain and discomfort by patients, and half due to the established incorrect position after immersion or possible malposition during the operation. It was not possible to reliably identify patients with an increased risk group either by gender or age. Patients who had stents implanted during the study period were satisfied with the result and could recommend this procedure to their relatives. The results of this relatively new operation in our country, in the author's opinion, are promising in the treatment of foot pathology in the early stages of the disease and in various age groups.

Background: The timing and strategy for operative treatment of flatfoot are still controversial. The purpose of this study was to evaluate clinical outcomes and radiographic changes following calcaneal Z osteotomy combined with subtalar arthroereisis for severe adolescent flexible flatfoot. Methods: Data were analyzed for 16 patients (20 feet) who had flatfoot without tibialis posterior tendon dysfunction and were treated by calcaneal Z osteotomy combined with arthroereisis between October 2011 and February 2015. The mean age of patients at the time of surgery was 12.8 ± 1.4 years (range, 10-14 years). Preoperative and postoperative measurements included changes in hindfoot valgus angles; changes in talonavicular uncoverage angles on anteroposterior (AP) radiographic view; and changes in talo-first metatarsal angles, talar pitch angles, and calcaneal pitch angles on lateral radiographic view. The American Orthopaedic Foot & Ankle Society Ankle-Hindfoot Score (AOFAS-AH) was used to assess foot function. The mean follow-up was 18.9 ± 6.9 months (range, 13-33 months). Results: The hindfoot valgus angle improved from 14.9 ± 4.2 degrees to 2.3 ± 1.7 degrees. On the AP view, the preoperative and postoperative talonavicular uncoverage angles were 30.5 ± 9.4 degrees and 9.8 ± 4.8 degrees, respectively. On lateral radiographs, the preoperative talo-first metatarsal angle, talar pitch angle, and calcaneal pitch angle were -22.1 ± 7.9 degrees, 36.1 ± 4.4 degrees, and 14.4 ± 4.0 degrees, respectively. Postoperative lateral radiographs demonstrated talo-first metatarsal angle, talar pitch angle, and calcaneal pitch angle of -6.2 ± 4.7 degrees, 27.3 ± 4.9 degrees, and 19.0 ± 4.3 degrees, respectively. The AOFAS-AH score improved from 66.8 ± 24.1 preoperatively to 96.5 ± 3.4 postoperatively. Conclusions: For adolescents with flatfoot, calcaneal Z osteotomy combined with subtalar arthroereisis provided satisfactory results.

Subtalar joint arthroereisis (STA) can be used in the management of adult acquired flatfoot deformity (AAFD), including posterior tibial tendon dysfunction. The procedure is quick and normally causes little morbidity; however, the implant used for STA often needs to be removed because of sinus tarsi pain. The present study evaluated the rate and risk factors for removal of the implant used for STA in adults treated for AAFD/posterior tibial tendon dysfunction, including patient age, implant size, and the use of endoscopic gastrocnemius recession. Patients undergoing STA for adult acquired flatfoot were prospectively studied from 1996 to 2012. The inclusion criteria were an arthroereisis procedure for AAFD/posterior tibial tendon dysfunction, age >18 years, and a follow-up period of ≥2 years. The exclusion criteria were hindfoot arthritis, age <18 years, and a follow-up period of <2 years. A total of 100 patients (average age 53 years) underwent 104 STA procedures. The mean follow-up period was 6.5 (range 2 to 17) years. The overall incidence of implant removal was 22.1%. Patient age was not a risk factor for implant removal (p = .09). However, implant size was a factor for removal, with 11-mm implants removed significantly more frequently (p = .02). Endoscopic gastrocnemius recession did not exert any influence on the rate of implant removal (p = .19). After STA for AAFD, 22% of the implants were removed. No significant difference was found in the incidence of removal according to patient age or endoscopic gastrocnemius recession. However, a significant difference was found for implant size, with 11-mm implants explanted most frequently.

We prospectively compared subtalar arthroereisis with lateral column calcaneal lengthening for the treatment of painful flatfeet. Twenty-four feet (mean age of patients 12.8 years) were treated. Kinematic motion analysis, pedobarometry, and radiography were performed, and the Oxford Ankle-Foot Questionnaire for Children was administered for each patient before surgery and at the 1-year follow-up. We found statistically significant improvements in both groups, with no difference in their outcomes. Both groups showed significantly improved hindfoot and midfoot motion and positioning. Hindfoot range of motion was preserved. Radiography and pedobarometry also revealed significant improvements. Subtalar arthroereisis is a valid and potentially less-invasive alternative to lateral column lengthening that merits further investigation.

Background: Flexible flatfoot is a normal finding in infants and the arch is shaped spontaneously in most children before the age of 10 years. Flexible flatfoot is a common deformity in both adolescent and adult populations. Objective: This prospective study aims to assess the functional and radiological outcomes of subtalar arthroereisis in adolescent patients with symptomatic flexible flatfoot. Methods: This is a prospective study and included 26 feet in 19 patients who underwent subtalar arthroereisis for symptomatic flexible flatfeet deformity. Preoperative and postoperative functional assessment based on the American Orthopedic Foot and Ankle Society (AOFAS) hindfoot scale. Radiographic parameters included preoperative and postoperative Kite`s angle, talonavicular coverage angle, Anterior-Posterior talo-1st metatarsal angle, Meary`s angle, talar declination angle, calcaneal inclination angle and lateral talocalcaneal angle. Results: The mean follow-up period was 22.5±9.4 months and the mean preoperative AOFAS score was 54.6±6.0, while the mean AOFAS score at the last follow-up visit was 86.3±3.9 (P<0.001).The mean preoperative and postoperative radiological measurements were 19.0°±8.2° and 7.4°±3.9° for the AP Talo-1st metatarsal angle (P<0.001); 23.6°±9.1° and 8.0°±4.0° for talonavicular coverage angle (P<0.001); 35.4°±3.7° and 24.1°±3.4° for Kite`s angle (P<0.003); 22.4°±6.1° and 7.5°±3.7° for Meary`s angle (P<0.001); 41.0°±4.4° and 25.2°±7.1° for talar declination angle (P<0.001); 13.5°±3.7° and 21.3°±3.6° for calcaneal inclination angle (P<0.001) and 52.4°±7.2° and 42.9°±4.8° for lateral talocalcaneal angle (P<0.041) respectively. Conclusion: Subtalar arthroereisis is an effective and minimally invasive procedure that showed clinical and radiological improvement for symptomatic flexible flatfoot in our study group.

Subtalar arthroereisis has been used for the treatment of symptomatic flexible flatfoot deformities in both pediatric and adult patients. Chronic sinus tarsi pain is the most common complication of this procedure and can be relieved by removal of the implant. We describe a case of spontaneous fusion of the subtalar joint after arthroereisis. This is an irreversible complication that should be described to the patient as a rare, but possible, outcome of arthroereisis of the subtalar joint.

Sinus tarsi implants are used in the treatment of symptomatic hyperpronating flexible flatfeet in children. Although some implants are inserted only into the sinus tarsi, others occupy both the sinus tarsi and the tarsal canal. The stem that is anchored in the tarsal canal depends on interference fit for the initial resistance to slippage. The first part of this computed tomography anatomic study in children was aimed at finding and measuring the dimensions in the narrowest point in the canal that provided the interference fit. The second part of the study assessed the possibility of the implant being loaded with axial body weight in the tarsal canal. All foot computed tomography scans performed consecutively at Birmingham Children's Hospital from January 2008 to December 2011 were reviewed to assess the tarsal canal dimensions on the sagittal views. A total of 52 scans fulfilled the inclusion criteria. The average age was 12.7 years. The narrowest mean anteroposterior diameter of the canal was 7.3 ± 1.12 (range 5.2 to 10.0) mm. The narrowest mean superoinferior diameter was 9.2 ± 1.32 (range 6.3 to 12.7) mm. A total of 50 patients had the narrowest dimension in the anteroposterior plane. A positive linear correlation was found between the anteroposterior diameter and the superoinferior distance (r = 0.51, p < .01). We have concluded that the stem of an arthroereisis implant extending into the tarsal canal is unlikely to be constantly bearing body weight, because it obtains an interference grip in the anteroposterior direction in almost all patients and not in the superoinferior line of axial body weight.

Background: Flatfoot deformities are common in children and are treated using many conservative and surgical approaches. Subtalar extra-articular arthroereisis, in particular, limits talar motion, spares the subtalar joint, and prevents excessive subtalar joint pronation. Addressing the underlying equinus deformity with gastrocnemius recession is an important factor in optimizing outcomes in patients with flatfoot deformity. Methods: This study included 20 children, 4 to 17 years old. The patients presented 34 cases of functional flexible flatfoot, and each was treated with gastrocnemius recession and a subtalar implant insertion of either a resorbable arthroereisis plug constructed of poly-L lactic acid or a threaded titanium alloy plug. Clinical evaluation was based on the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Scale as well as subjective assessments of pain, function, shoe wear, and overall preoperative and postoperative satisfaction. Results: The average AOFAS Ankle-Hindfoot Scale reading improved by 21.3 points (standard deviation = 8.1; 95% confidence interval = 17.5-25.1), from an average preoperative reading of 67.7 points to an average postoperative reading of 89 points (P < .0001). Subjectively, patients experienced reduced pain and improved function, cosmesis, and shoe wear. Conclusions: Treating equinus deformity with gastrocnemius recession significantly improved patient outcomes when treating flatfoot deformity. Reconstructive flatfoot surgery that combined subtalar arthroereisis with a resorbable arthroereisis plug and gastrocnemius recession resulted in favorable clinical outcomes and patient satisfaction. Symptom improvement and preservation of the subtalar joint were seen with these procedures, which are reasonable and useful options in treating children with symptomatic flexible flatfoot.

The present multicenter, prospective study evaluated the subjective outcomes in patients after extraosseous talotarsal stabilization using the HyProCure(®) stent as a standalone procedure for the treatment of recurrent and/or partial talotarsal joint dislocation (RTTD) in a population of pediatric and adult patients. RTTD has been cited as a possible etiology for a number of foot ailments and might contribute to the development of pathologic features localized more proximally in the weightbearing musculoskeletal chain. Correction of RTTD might, therefore, lead to the reduction of pathologic features associated with this deformity. A total of 46 feet in 35 patients were included in the present investigation. Subjective evaluation used the Maryland Foot Score assessment, which was obtained preoperatively and 1, 2, and 3 weeks, 1, 2, 3, and 6 months, and 1 year postoperatively. The mean overall scores improved from a preoperative value of 69.53 ± 19.56 to a postoperative value of 89.17 ± 14.41 at the 1-year follow-up. Foot pain decreased by 36.97%, foot functional activities improved by 14.39%, and foot appearance improved by 29.49%. The greatest magnitude of improvement occurred 4 weeks postoperatively, with gradual improvement continuing through to the 1-year follow-up. Implants were removed from 2 patients (2 feet, 4.35%). No unresolved complications were observed. The positive subjective outcomes resulting from the extraosseous talotarsal stabilization procedure suggest that the intervention employing the device we have described alleviates pain and improves foot function and appearance in patients with RTTD.

Plantar pressure measurements have long been used by clinicians to provide information regarding potential impairments and disorders of the foot and ankle. Elevations in peak plantar pressures or a poor distribution of these pressures can be an indication of pathomechanics in the foot. Lower extremity deficits such as sensory impairment, foot deformities, limited joint mobility, and reduced plantar tissue thickness have been associated with high plantar pressures. The total pressures, pressure distribution, and peak pressures provide useful information to evaluate the abnormal functioning of the talotarsal joint. Instability of the talotarsal joint can result in excessive forces exerted on the joints and surrounding tissues in the foot that can then lead to dysfunction of the proximal musculoskeletal kinetic chain. In the present study, we performed a retrograde analysis of the pre- and postoperative measurements of the peak plantar pressures, peak forces, and area of contact between the foot and the ground during each phase of the gait cycle for 6 patients (12 feet) who had undergone a bilateral extraosseous talotarsal stabilization procedure using a type II extraosseous talotarsal stabilization device. After the procedure, a significant reduction was seen in the peak pressures (42%) over the entire foot and a significant increase in the contact area (19.7%) between the foot and the floor. This could imply that the extraosseous talotarsal stabilization procedure was effective in stabilizing the talotarsal joint complex, thus eliminating abnormal hindfoot motion and restoring the normal biomechanics of the foot and ankle complex, as indicated by a reduction and realignment of the peak plantar pressures and forces.

The authors present a retrospective study of 35 consecutive patients (60 feet) treated with the Maxwell-Brancheau Arthroereisis (MBA) implant. The mean age of the cohort at the time of surgery was 14.3 (range 5 to 46) years, and 22 (62.86%) men and 13 (37.14%) women were included. Preoperative and postoperative anteroposterior and lateral foot radiographs were compared at a mean of 36 (range 18 to 48) months postoperatively, and the following mean changes were reported: talocalcaneal angle 24.15° ± 7.97° to 18.53° ± 8.23°, calcaneocuboid angle 18.67° ± 8.72° to 11.76° ± 8.49°, first to second intermetatarsal angle 9.42° ± 2.67° to 7.61° ± 2.69°, calcaneal inclination angle 11.93° ± 6° to 14.93° ± 5.85°, and talar declination angle 34.0° ± 8.59° to 28.02° ± 6.85°; all of these differences were statistically significant (p < .0001). A subgroup of 24 (68.57%) patients also answered a subjective questionnaire at a mean of 33 (range 12 to 55) months postoperatively. The presenting chief complaints were resolved in 23 patients (95.83%) of the subgroup, and 21 patients (87.5%) returned postoperatively to either the same or a greater activity level in sports. Twenty-three (95.83% of the subgroup) patients said they were 75% to 100% satisfied with their surgical outcome, and that they would recommend the surgery to a friend or family member with the same condition, whereas 1 (4.17%) claimed 0% satisfaction after placement of inappropriately sized implants (which were later replaced to the patient's clinical satisfaction) in both feet.

Subtalar joint arthroereisis remains a popular procedure for a flexible flatfoot deformity. Potential complications of the procedure have been discussed in published reports and are often believed to have resulted from shortcomings related to the mechanical properties of the biomaterial, implant size, and/or implant placement. In the present report, we describe the case of a talar neck fracture with migration of the implant after subtalar joint arthroereisis performed 10 years earlier. The 19-year-old patient was treated with implant removal and open reduction internal fixation and bone void filler and recovered unremarkably thereafter.

Background: Type II accessory naviculars are frequently associated with planovalgus deformity. Operative treatment for patients recalcitrant to nonoperative treatment involves resection, with or without takedown, and reattachment of the tibialis posterior tendon as described by Kidner. This does not address the planovalgus deformity. The authors hypothesized that adding a subtalar arthroereisis to the Kidner procedure would lead to improvement of pain and function and correction of the deformity. Methods: Institutional Review Board-approved, prospectively collected data were reviewed for 20 patients (23 feet), who underwent a combined modified Kidner and subtalar arthroereisis for painful type II accessory navicular with planovalgus deformity recalcitrant to nonoperative treatment. The average age at the time of surgery was 18 years. Patients were evaluated preoperatively and at final follow-up clinically, radiographically, and via the visual analog pain scale (VAPS), the American Orthopaedic Foot and Ankle Society (AOFAS) ankle hindfoot score, and a satisfaction rating. Mean follow-up was 53.9 months. Results: The mean AOFAS scores improved from 53 preoperatively to 95 at final follow-up and the mean VAPS score decreased from 7.4 preoperatively to 1.7 at final follow-up. Radiographically, the average Meary's angle improved from 18.5° apex plantar preoperatively to 3° apex plantar on weight-bearing lateral radiographs, and the average talar head uncoverage percentage on weight-bearing anteroposterior radiographs improved from 24% preoperatively to 3%. Nineteen of 20 patients reported good or excellent results. Three patients required implant removal because of pain; no recurrence of planovalgus deformity occurred after implant removal. No patients developed subtalar arthritis. Conclusion: The modified Kidner procedure combined with a subtalar arthroereisis resulted in significant pain and functional improvement. The deformity correction obtained at surgery was maintained even if the arthroereisis plug was removed. The extra-articular plug did not lead to subtalar arthritis.

The purpose of this study was to determine radiographic correction achieved in adult patients treated with an extraosseous talotarsal stabilization (EOTTS) procedure. Patients diagnosed with flexible/reducible talotarsal joint dislocation (partial) underwent surgical correction with the HyProCure(®) EOTTS device. Preoperative and postoperative weightbearing radiographs taken in the anteroposterior (AP) and lateral views for a total 95 feet (in 70 patients) were analyzed to determine standardized radiographic angles, and to quantify the correction obtained after the EOTTS procedure. Postoperative radiographs were taken at an average follow-up of 17 days from the surgery date. The mean preoperative and postoperative talar second metatarsal angles (measured from the AP radiographs) were 24.8° ± 1.0° and 5.8° ± 0.9°, respectively, that is, mean decrease by 19°. The mean preoperative and postoperative talar declination angles (measured from the lateral radiographs) were 25.1° ± 0.7° and 19.4° ± 0.5°, respectively, that is, mean decrease by 5.7°. The mean preoperative and postoperative calcaneal inclination angles (measured from the lateral radiographs) were 21° ± 0.7° and 21.8° ± 0.7°, respectively, that is, mean increase by 0.8°. Postoperatively, the talar second metatarsal and talar declination angles were reduced to average values reported in the literature for normal feet. This study shows the efficacy of a minimally invasive EOTTS procedure in restoring the normal angular relationships between hindfoot and forefoot osseous structures on weightbearing, in both the transverse and sagittal planes. This indicates stabilization of the talotarsal joint complex and elimination of hyperpronation, which may lead to reduced pain, improved foot functional abilities, and patient satisfaction.

Excessive abnormal strain or tension on the posterior tibial nerve in feet exhibiting talotarsal instability has been considered one of the possible etiologic factors of tarsal tunnel syndrome. The suggested treatment options in such cases include stabilization of the talotarsal joint complex in a corrected position, which might help minimize the abnormal forces placed on the posterior tibial nerve due to over stretching. The primary goal of this study was to quantify strain on the posterior tibial nerve in feet exhibiting hyperpronation caused by talotarsal instability, before and after an extra-osseous talotarsal stabilization (EOTTS) procedure. We hypothesized that the excessive strain placed on the posterior tibial nerve in hyperpronating cadaveric feet would be reduced significantly after intervention using the HyProCure(®) EOTTS device. Posterior tibial nerve strain was quantified in 9 fresh-frozen cadaver specimens. A miniature differential variable reluctance transducer was used to measure nerve elongation as the foot was moved from its neutral to a maximally pronated position, before and after intervention. The mean elongation of the posterior tibial nerve (with respect to a fixed reference point) decreased by 43% after the EOTTS procedure (i.e., from 5.91 ± 0.91 mm to 3.38 ± 1.20 mm; N = 27). The reduction was statistically significant at p < .001. HyProCure(®) was effective in stabilizing the talotarsal joint complex, thus reducing the excessive amount of strain placed on the posterior tibial nerve. Clinical implications of this study suggest the use of EOTTS devices in the treatment of tarsal tunnel syndrome.

Posterior tibial tendon dysfunction is considered one of the most common causes of progressive adult acquired flatfoot deformity. The etiology leading to the dysfunction of posterior tibial tendon remains controversial. The purpose of this study was to quantify strain on the posterior tibial tendon in cadaver feet exhibiting hyperpronation caused by flexible instability of the talotarsal joint complex. We hypothesized that posterior tibial tendon strain would decrease after a minimally invasive extra-osseous talotarsal stabilization procedure. A miniature differential variable reluctance transducer was used to measure the elongation of posterior tibial tendon in 9 fresh-frozen cadaver specimens. The elongation was measured as the foot was moved from its neutral to maximally pronated position, before and after intervention with the HyProCure(®) extra-osseous talotarsal stabilization device. The mean elongation of the posterior tibial tendon (with respect to a fixed reference point) was found to be 6.23 ± 2.07 mm and 3.04 ± 1.85 mm, before and after intervention, respectively (N = 27; variation is ± 1 SD). The average elongation reduced by 51% and was statistically significant with p < .001. Strain on the posterior tibial tendon is significantly higher in hyperpronating feet. An extra-osseous talotarsal stabilization procedure reduces excessive abnormal elongation of the posterior tibial tendon by minimizing excessive abnormal pronation. This minimally invasive procedure may thus provide a possible treatment option to prevent or cure posterior tibial tendon dysfunction in patients exhibiting flexible instability of the talotarsal joint complex.

Abnormal talotarsal joint mechanics leading to hyperpronation is implicated as one of the most common causes of plantar fasciopathy. In patients with hyperpronating feet, the plantar fascia experiences excessive tensile forces during static and dynamic weight-bearing activities because of excessive medial longitudinal arch depression. For the purposes of this study, we hypothesized that plantar fascia strain in hyperpronating cadaveric feet would decrease after intervention with an extra-osseous talotarsal stabilization (EOTTS) device. A miniature differential variable reluctance transducer was used to quantify the plantar fascia strain in 6 fresh-frozen cadaver foot specimens exhibiting flexible instability of the talotarsal joint complex (i.e., hyperpronation). The strain was measured as the foot was moved from its neutral to maximally pronated position, before and after intervention using the HyProCure(®) EOTTS device. The mean plantar fascia elongation was 0.83 ± 0.27 mm (strain 3.62% ± 1.17%) and 0.56 ± 0.2 mm (strain 2.42% ± 0.88%) before and after intervention, respectively (N = 18, variation reported is ± 1 SD). The average plantar fascia strain decreased by 33%, and the difference was statistically significant with p < .001. From this cadaveric experiment, the reduction in plantar fascia strain suggests that an EOTTS device might be effective in stabilizing the pathologic talotarsal joint complex and the medial longitudinal arch and in eliminating hyperpronation. An EOTTS procedure might offer a possible treatment option for plantar fasciopathy in cases in which the underlying etiology is abnormal talotarsal biomechanics.

The navicular drop in the sagittal plane on weight-bearing is a valid indicator of foot pronation. Dislocation of the talus on the tarsal mechanism results in hyperpronation, which can lead to excessive navicular drop. The purpose of the present study was to radiographically determine the efficacy of HyProCure(®) in realigning the navicular bone in hyperpronating feet. We hypothesized that following the placement of HyProCure(®), the navicular height would increase significantly compared to its preoperative value. Radiographs of 61 adult patients (86 feet) who received HyProCure(®) without adjunctive hindfoot or midfoot soft tissue or osseous procedures were analyzed. The distance of the navicular with respect to the cuboid was measured from the pre- and postoperative weight-bearing lateral radiographs. Additionally, we measured foot length to normalize the navicular to cuboid distance. The postoperative radiographs were taken at an average follow-up of 17 days. The mean preoperative true navicular to cuboid distance was 19 ± 6 mm as compared to a mean postoperative value of 24 ± 5 mm. The mean pre- and postoperative normalized navicular to cuboid distances were 0.098 ± 0.029 and 0.125 ± 0.027, respectively (± 1 SD). The postoperative increase in the true and normalized navicular to cuboid distance was statistically significant (p < .001). HyProCure(®) was effective in improving the anatomic alignment of the talonavicular joint by reducing excessive navicular drop. This indicates reduction of excessive abnormal pronation and stabilization of the medial column of the foot, which can also lead to reduction in the excessive forces placed on the supporting soft tissue structures.

Background: The foot is the foundation of the body. The stability of the osseous hindfoot structure is crucial in bipedal locomotion. The subtalar joint is responsible for conversion of the rotatory forces of the lower extremities and dictates the movements of the midtarsal joints and the forefoot. In a hyperpronated foot, excessive abnormal pronation results in partial to full obliteration of the sinus tarsi. The hypothesis is that the HyProCure device will prevent obliteration of the sinus tarsi, thereby stabilizing the subtalar joint complex and eliminating the excessive forces to the proximal and distal musculoskeletal system that occur with every step. Methods: Five fresh-frozen human foot cadaver specimens that represented pathologic hindfoot and midfoot instability and partial to full obliteration of the sinus tarsi were axially compressed to 2,000 N and internally rotated by 15° to produce maximum pronation of the subtalar joint using a biaxial materials testing machine. The forces were measured across the posterior and anterior talocalcaneal joint facets before and after placement of the HyProCure stent. Results: The subtalar joint stabilized after placement of the HyProCure sinus tarsi stent. The mean ± 1 SD forces in the posterior talocalcaneal joint increased from 795.88 ± 106 N to 1,004.86 ± 72.41 N (P < 0.05, two-tailed paired t test). The mean ± SD forces at the anterior talocalcaneal joint decreased from 520.15 ± 127.18 N to 394.56 ± 73.83 N (P < 0.05), shifting the contact area posteriorly. Conclusions: Placement of the HyProCure subtalar stabilization stent in a hyperpronated foot prevents excessive talar subluxation and assists in proper distribution of the axial loads on the subtalar facet joints.

Background: Pediatric flexible flatfoot is a common deformity for which a small, but significant number undergo corrective surgery. Arthroereisis is a technique for treating flexible flatfoot by means of inserting a prosthesis into the sinus tarsi. The procedure divides opinion in respect of both its effectiveness and safety. Methods: A database search up until 2010 was used to find articles regarding arthroereisis in pediatric patients. We summarized the findings of this study. Results: Seventy-six studies were identified. Eight of the nine radiographic parameters reported show significant improvement following arthroereisis reflecting both increased static arch height and joint congruency. Calcaneal inclination angle demonstrated the least change with only small increases following arthroereisis. Arthroereisis remains associated with a number of complications including sinus tarsi pain, device extrusion, and under-correction. Complication rates range between 4.8% and 18.6% with unplanned removal rates between 7.1% and 19.3% across all device types. Conclusion: Current evidence is limited to consecutive case series or ad hoc case reports. Limited evidence exists to suggest that devices may have a more complex mode of action than simple motion blocking or axis altering effects. The interplay between osseous alignment and dynamic stability within the foot may contribute to the effectiveness of this procedure. Although literature suggests patient satisfaction rates of between 79% to 100%, qualitative outcome data based on disease specific, validated outcome tools may improve current evidence and permit comparison of future study data.

Tarsal tunnel syndrome is characterized by increased pressure in the tarsal tunnel. In hyperpronation, there is excessive abnormal pronation resulting from partial displacement of the talus on the calcaneus. In this study, we hypothesized that hyperpronation caused by talotarsal instability will lead to increased pressure in the tarsal tunnel and porta pedis. We also hypothesized that the pressure in these compartments will decrease following an extra-osseous talotarsal stabilization procedure using HyProCure(®). Pressures in the tarsal tunnel and porta pedis were measured in 9 fresh-frozen cadaver specimens using an intracompartmental pressure monitor system. Pressures were measured with the foot in neutral and hyperpronated position, before and after stabilization using HyProCure. For the tarsal tunnel, pressure in the neutral position with and without HyProCure was 3 ± 3 mm Hg and 4 ± 3 mm Hg, respectively (P = .159). However, for the hyperpronating foot, the pressure decreased from 32 ± 16 mm Hg to 21 ± 10 mm Hg (P < .001) following the placement of HyProCure. In the porta pedis, pressure in the neutral position with and without HyProCure was 2 ± 2 mm Hg and 2 ± 2 mm Hg, respectively (P = .168). However, for the hyperpronating foot, the pressure decreased from 29 ± 15 mm Hg to 18 ± 11 mm Hg (P < .001) following the placement of HyProCure. The pain caused by compression of the posterior tibial nerve in the tarsal tunnel and its branches in the porta pedis, owing to hyperpronation, may be alleviated by implantation of HyProCure.

The purposes of this study were to evaluate the outcome of pediatric patients who have undergone Maxwell-Brancheau arthroereisis (MBA) subtalar implants for the treatment of painful pediatric flatfoot deformities. In a retrospective study, 39 patients (68 feet) were evaluated clinically and radiographically. The mean age of the patients was 12 years (range, 6-16 years). The mean period of follow-up was 24 months (range, 6-61 months). Statistical evaluation was performed on all radiographic measurements. Additional surgical procedures (gastrocnemius recession, Achilles tendon lengthening, Kidner posterior tibial tendon advancement) were performed in 22 of 68 feet. There were 10 (15%) complications, which consisted of 10 reoperations in 10 feet. Implants were exchanged in 9 feet because of implant migration, undercorrection, and overcorrection. There was 1 reoperation (in 1 foot) for implant removal because of persistent sinus tarsi pain. Radiographic evaluation demonstrated an improvement of all parameters determined. The parameters that were evaluated include talonavicular joint coverage, as well as lateral and anterior-posterior talocalcaneal angles. There were significant changes noted in pre- and postoperative measurements (P < .001). The MBA implant is effective for the correction of painful, flexible flatfoot deformity in children in short-term follow-up. However, this is a multiplanar deformity, and additional procedures may be needed in addition to the MBA.

Background: The purpose of this study was to determine the functional outcomes and radiographic results of adult patients who had an operation for flexible flatfeet without any hindfoot osteotomies or fusions. Methods: Twenty-eight feet in 23 patients with problems caused by their flexible flatfoot deformities had reconstructive foot and ankle surgery that included a subtalar arthroereisis (the restriction of the range of motion of a joint) with the Maxwell-Brancheau Arthroereisis (MBA) sinus tarsi implant. The American Orthopedic Foot and Ankle Society (AOFAS) Hindfoot Scale and a patient assessment questionnaire were obtained from all patients before surgery and at final follow-up. Preoperative and postoperative standing radiographs were analyzed to determine radiographic correction of the deformities. The average followup was 44 months. The MBA implant was surgically removed in 11 of 28 feet (39%) because of sinus tarsi pain. Results: The average preoperative AOFAS score was 52 and had improved to 87 (p < 0.00001) at final followup. The average response to four of five questions in the patient assessment had significantly improved (p < 0.05). On a 10-point scale, average patient satisfaction was 8.3 points; 78% said that they would have the surgery again. Correction after surgery was significant (p < 0.0001) in each of the three radiographic parameters evaluated for ‘correction with MBA’ and ‘final correction.’ With the numbers available, no significant differences could be detected after the MBA was removed. Complications included sinus tarsi pain in 46% (13) of the 28 feet in this study; after implant removal, 73% (8) of 11 feet had less discomfort than before surgery with AOFAS scores 80 or better. Conclusions: Reconstructive foot and ankle surgery that included a subtalar arthroereisis with the MBA sinus tarsi implant resulted in favorable clinical outcomes and patient satisfaction in 78% (18) of 23 patients. In spite of the high incidence of temporary sinus tarsi pain until the implant was removed, this operative approach compares favorably with other operations for flexible flatfoot deformities in adults.

This study was designed to ascertain if there was a statistically significant correction in the foot and to determine the overall health of a child after an arthroereisis procedure. Thirty-seven patients (67 feet) who had undergone Maxwell-Brancheau arthroereisis were retrospectively reviewed at an average of 18.4 months after surgery. The pre- and postoperative lateral talo-first metatarsal and talar declination and the anteroposterior talo-first metatarsal and talocalcaneal angles were measured by using an X-Caliper device (Eisenlohr Technologies, Davis, CA); significance was determined with a t test. Child health questionnaire answers were calculated and converted to a 0 to 100 scaled score and statistically compared with population norms by using a single-sample t test. The lateral radiographic average preoperative talo-first metatarsal and talar declination angles were 11.3 and 27.5, respectively, and were 3.7 and 21.9, respectively, postoperatively. The preoperative average anteroposterior talo-first metatarsal and talocalcaneal angles were 13.8 and 25.6, respectively, and were 6.4 and 19.4, respectively, postoperatively. The t test showed the postoperative angles had a statistically significant (P <.01) change from the preoperative angles. The results of the Child health questionnaire of our 34 pediatric patients (92%) showed scores in 3 domains (role emotional behavior, global behavior, parent time) that were better than population norms, and there was no difference in the remaining domains.

Successful management of the flexible flatfoot deformity relies not only on correcting causal factors, but also on addressing the adaptive changes that have occurred and any coexisting deformities present. The three primary goals of any therapy--relief of pain, biomechanical control of excessive pronation, and prevention of the progression of the deformity--should be considered. With thorough assessment of causal factors and planal dominance of the deforming and compensative forces, one can expect to increase the predictability and success of the surgical management of PTTD in the flexible adult flatfoot deformity.

Introduction: Flexible flat foot is one of the most common foot conditions found amongst any age group across the world. One very important reason for this condition is the incongruency or partial dislocation of one or more joints within the talo-tarsal mechanism. This flexible talo-tarsal malalignment is termed as recurrent talo-tarsal joint dislocation (RTTJD). Materials and methods: Between 2016 and 2018, 32 patients were advised Extra osseous talo-tarsal stabilization (EOTTS) as a standalone procedure for RTTJD following detailed clinical examination including foot posture index (FPI) scoring and weight-bearing radiographic evaluation. Subjective assessment was done through Maryland Foot Score (MFS) questionnaire. Radiological parameters like talar declination angle, talar second metatarsal angle and tibio-calcaneal valgus angle were assessed for preoperative and postoperative comparison. 15 patients (20 feet) underwent surgery and rest 17 patients (25 feet) became our control group. A retrospective record analysis of longitudinal data was done over a period of 4 years. The purpose of this study is to depict the short-term results of EOTTS procedure in terms of functional and radiological improvement and compare it with the non-surgical group. Result: Significant improvement was seen in MFS from 67.31 ± 16.04 to 95.47 ± 4.36 over a mean follow-up period of 30.66 ± 7.09 months. Total FPI improved by 96.83 ± 4.80% at final follow-up of EOTTS group. Radiologically, maximum correction achieved was in coronal plane (93.07 ± 30.05%). Conclusion: EOTTS, as a standalone procedure improved the foot radiological angles and restored the normal foot biomechanics significantly in presence of competent spring ligament and posterior tibial tendon. This procedure resulted in excellent patient satisfaction score as assessed by MFS questionnaire.