Subtalar Arthroereisis for the Correction of Planovalgus Foot in Children with Neuromuscular Disorders

We studied the results of 140 STA-peg arthroereisis procedures performed for the treatment of planovalgus foot deformity in 78 ambulatory children with neuromuscular disease. Patient age at surgery ranged from 2 + 2 to 14 + 11 years, with a mean of 7 + 9 years. Patients were followed up for an average of 4 + 6 years. The ultrahigh-molecular-weight polyethylene (UHMWPE) STA-peg implant is inserted laterally into the subtalar joint such that its stem extends inferiorly into the calcaneus and its collar abuts the inferior surface of the lateral process of the talus, thereby blocking excessive valgus tilt of the calcaneus. All but five patients (nine feet) had concomitant soft-tissue procedures to balance the foot. The talocalcaneal angle and the talar declination angle were measured on lateral radiographs preoperatively, postoperatively, and at the latest follow-up visit. Patients were evaluated for the presence of pain and hindfoot valgus deformity. Satisfactory results were achieved in 135 (96.4%) feet. Results were unsatisfactory in one foot of each of five patients who had bilateral procedures; one was painful, and four developed varus. The STA-peg was removed in these five patients. No infections or adverse tissue reactions to the STA-peg implant were observed. STA-peg arthroereisis, combined with satisfactory musclebalancing procedures, can predictably achieve control of planovalgus foot deformity in children with neuromuscular disorders and may obviate the need for long-term orthotic wear.