Extraosseous talotarsal stabilization using HyProCure®: preliminary clinical outcomes of a prospective case series

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.

Prospective, Long-Term Functional Outcomes of Extra-Osseous Talotarsal Stabilization (EOTTS) Using HyProCure in Adult Patients with Talotarsal Joint Instability: Assessment of Physical Activity and Patient Satisfaction

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.

Patient Outcomes Following Extra-Osseous Talo-Tarsal Stabilization for Foot Hyperpronation

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.

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.

Short Term Clinico-Radiological Outcome of Extra Osseous Talo-Tarsal Stabilization (EOTTS) in Flat Foot: An Indian Perspective

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.

LEVEL OF EVIDENCE

III.

Flexible Progressive Collapsing Foot Deformity: Is There Any Role for Arthroereisis in the Adult Patient?

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.

Finite element analysis of subtalar joint arthroereisis on adult-acquired flexible flatfoot deformity using customised sinus tarsi implant

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.

Comparison of Extraosseous Talotarsal Stabilization Implants in a Stage II Adult-Acquired Flatfoot Model: A Finite Element Analysis

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.