A 58-Years Old Women Underwent Triple Arthrodesis for Adult Acquired Flatfoot Deformity Grade IV with Posterior Tibial Tendon Insufficiency Post Failed Reconstruction: A Case Report

Abstract

Background: Adult acquired flatfoot (AAFD), formerly known as posterior tibial tendon dysfunction (PTTD), involves the gradual collapse of the foot arch, leading to ongoing deformity. The posterior tibial tendon, crucial for foot stability, is often implicated. A lack of comprehensive epidemiological data exists, but the condition is prevalent, especially among the elderly and those with chronic vascular diseases. Dysfunction of the posterior tibial tendon causes instability in the foot, leading to lateral displacement of forces and subsequent deformities. Triple arthrodesis is an effective treatment for correcting foot deformities, offering pain relief and stability, particularly in cases of arthrosis and neuromuscular diseases. This case report highlights a Grade IV AAFD with failed reconstructive surgery, contributing to the literature on surgical intervention outcomes.

Case report: We present the case of a 58-year-old woman with progressively worsening pain and discomfort in her left foot. The patient underwent a triple arthrodesis procedure for adult acquired flatfoot deformity grade IV with posterior tibial tendon insufficiency. the patient has a history of failed reconstructive surgery with medial displacement calcaneal osteotomy and flexor digitorum longus to posterior tibial tendon transfer. Physical examination findings revealed presence of surgical scars on the left pedis region consistent with prior interventions. There is evidence of hindfoot valgus and medial arch collapse, justifying the need for further surgical intervention in radiology finding.

Discussion: Stage IV acquired flatfoot deformity results from weakened deltoid ligament and Posterior Tibial Tendon Dysfunction (PTTD), leading to hindfoot valgus and abduction. Surgical options include medializing calcaneal osteotomy (MCO) and tendon transfers like flexor digitorum longus (FDL). Triple arthrodesis is preferred for rigid deformities, but whether to include the calcaneocuboid joint depends on examination findings. Exclusion may cause arthrodiastasis, with limited evidence of improved outcomes. Double arthrodesis has higher nonunion rates but doesn't impair correction.

Conclusion: Individuals with rigid foot deformities, triple arthrodesis, fusing the talonavicular, subtalar, and calcaneocuboid joints, improves pain relief and function. The decision to include the calcaneocuboid joint depends on its condition. Excluding it may cause unintended joint movement, but its distraction doesn't necessarily improve outcomes. After talonavicular fusion, calcaneocuboid joint motion is minimal. Double arthrodesis for rigid planovalgus deformity shows higher nonunion rates and lower patient scores compared to triple arthrodesis, but it doesn't impair deformity correction. This case contributes to the growing evidence supporting triple arthrodesis as a salvage procedure for advanced flatfoot deformities and serves as a valuable reference for managing similar challenging cases.