Subtalar arthroereisis as an adjunct for treatment of the flexible adult acquired flatfoot deformity - a 9 years experience

J. Dhaliwal, T. Goff, D. Carmody, A. Wines

Background: The purpose of this study is to evaluate the use of subtalar arthroereisis as an adjunct in the surgical management of the flexible adult acquired flatfoot deformity.

Methods: Two hundred and twenty-nine feet in 214 adult patients with Stage IIA acquired flatfoot deformity had reconstructive surgery including a medialising calcaneal osteotomy, flexor digitorum longus tendon transfer, and implantation of a subtalar arthroereisis device, during the study period (2010-2018). Clinical assessment was performed with FAOS scores. Post-operative questionnaire including patient satisfaction, how likely to have same surgery again were completed. Impact of implant removal was considered.

Results: 150 women and 64 men were included, mean age 57 years (24-82). Mean follow up was 2.4 years (6 months - 5.1 years). Subtalar arthroereisis implant was removed in 108 feet (47%) for lateral hind foot pain at an average of 8.5 months (6-26 months) following the primary procedure, with symptom resolution in all but 4 cases later necessitating subtalar arthrodesis. No significant difference in post-operative FAOS scores was observed between patients with retained implant versus implant removed (p= 0.6). Patients who had Achilles lengthening performed had lower rate of implant removal but difference was not statistically significant. Post-operatively 95% of patients were either satisfied or very satisfied with the results of their surgery.

Conclusions: Reconstruction of the flexible adult acquired flat foot with an adjunctive subtalar arthroereisis resulted in satisfactory reproducible clinical outcomes in the medium term. Implant removal is considered by the authors for persistently symptomatic patients but does not appear to adversely impact outcome.