Biomechanical assessment of two types and two different locations of subtalar arthroereisis implants for flexible flatfoot: A cadaveric study

Mid-term assessment of subtalar arthroereisis with Talar-Fit implant in pediatric patients with flexible flatfoot and comparing the difference between different sizes and exploring the position of the inserted implant

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.

Clinical Outcomes Following Treatment of Recurrent Talotarsal Joint Dislocation Using a Type II Extraosseous Talotarsal Stabilization Implant-A Long-Term Follow-Up Study

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.

HyProCure for Pediatric Flexible Flatfoot: What Affects the Outcome

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.