Temporary screw epiphyseodesis of the distal tibia: a therapeutic option for ankle valgus in patients with hereditary multiple exostosis.

Abstract

Ankle valgus in multiple hereditary exostoses (HME) is frequently seen and may result in activity related pain, deformity, or even early degenerative arthritis. Standard treatment protocols do not exist. The effect of medial screw hemiepiphysedesis of the distal tibia to correct ankle valgus is evaluated in this patient population. A retrospective review of 9 patients with HME and ankle valgus deformity (15 affected extremities) who were treated by a screw hemiepiphyseodesis of the medial physis of the distal tibia is presented. Mean age at time of operation was 11.8 ± 1.6 years (range: 9.6 to 14.7 y). All patients underwent clinical and radiological evaluation. To define the magnitude of ankle valgus we evaluated tibial tilt angle and Malhotra stations preoperatively, at time of screw removal and/or at time of the most recent clinical follow-up. In 11 extremities the screws were removed after an average time of 22.6 ± 8.0 months (range: 12 to 35 mo) and all patients were examined after a mean time of 36.7 ± 18.7 months after hemiepiphyseodesis (range: 13 to 69 mo). The mean preoperative tibiotalar tilt was 14.3 ± 4.4 degrees (range: 9 to 22 degrees). At time of screw removal the tibiotalar tilt was normalized to 0.4 ± 1.7 degrees (range: -2 to 4 degrees), according to a mean rate of correction of 0.58 ± 0.23 degrees by the month (range: 0.23 ± 0.92 degrees). With follow up 4 ankles demonstrated a change in the fibular station. None of the patients overcorrected into a severe varus, one patient developed a recurrent ankle valgus. The temporary screw hemiepiphyseodesis of the distal tibial physis is an effective, technically simple, and minimally invasive technique to correct ankle valgus deformity in children with HME. IV.