Subtalar arthroereisis for pediatric flexible pes planovalgus: fifteen years experience with the cone-shaped implant.

Flexible pes planovalgus is a common condition with flattening of the medial longitudinal arch accompanied by hindfoot valgus. Severe cases of pes planovalgus may need surgery, and a technique that has gained popularity over the past decades is subtalar arthroereisis. An endoorthotic implant of various shapes is inserted in the sinus tarsus, which limits the excessive eversion of the subtalar joint present in flexible pes planovalgus. None of these implants, however, allow for easy control of the extent of talocalcaneal and talonavicular correction. The primary aim of this study was to describe our technique with the custom-built cone-shaped implant. Our secondary aim was to evaluate patient satisfaction, clinical and radiologic results, and complications with a minimal follow-up of 5 years. Between January 1992 and June 2002, 40 patients (80 feet) underwent subtalar arthroereisis for flexible pes planovalgus. After temporary sinus tarsi tenderness (12 feet), implant dislocation (two feet) was the most common complication. Questionnaires from 27 patients (54 feet) were analyzed and 44 feet were also clinically and radiographically evaluated. Thirteen patients were lost to follow-up. Mean (+/- SD) follow-up was 12.6 years (range, 5.9-16.1). Eighty-one percent of the patients were satisfied with the result. Clinically, normal alignment was present in 14 feet, and mild deformities remained in 26 feet. Radiographically, the average foot angle measurements were normal. We conclude that subtalar arthroereisis is a simple, minimally invasive operative option with satisfactory subjective and clinical results after mid- to long-term follow-up.