Correction and recurrence of ankle valgus in skeletally immature patients with multiple hereditary exostoses.

BACKGROUND: Ankle valgus is encountered in children with a variety of congenital musculoskeletal disorders, including multiple hereditary exostoses (MHE). Guided growth with temporary distal tibial medial hemiepiphysiodesis (DTMH) may correct the deformity; however, exostoses about the ankle commonly observed in MHE patients may hinder correction and increase the risk of recurrence. Thus, the purpose of this study was to review the outcomes of DTMH in treatment of ankle valgus in MHE versus other diagnosis (non-MHE).

METHODS: Medical records and radiographs of patients undergoing DTMH for ankle valgus between January 1, 2005, and November 1, 2010, at a single pediatric orthopedic hospital were retrospectively analyzed. Radiographs obtained preoperatively and at 6-month intervals postoperatively were reviewed and the tibiotalar angle was measured.

RESULTS: Fifty-eight ankles in 41 patients met inclusion criteria, with minimum follow-up of 12 months (mean, 34 months). Mean age was 10 years (range, 4-14 years). MHE was the most common underlying diagnosis (19 ankles, 33%). The rate of tibiotalar angle correction (mean ± standard deviation) with hardware in place was 0.37 ± 0.28 deg/mo in MHE ankles and 0.51 ± 0.42 deg/mo in non-MHE ankles (P = .161). Following hardware removal, the rate of recurrence was faster in MHE (0.29 ± 0.25 deg/mo) compared with non-MHE ankles (0.12 ± 0.19 deg/mo) (P = .059), and more total recurrent valgus deformity was observed in MHE (7.8 ± 8.2 degrees) than non-MHE ankles (3.4 ± 4.6 degrees) (P = .08) over a similar follow-up period (mean 23.4 vs 23.6 months, respectively), with differences approaching statistical significance.

CONCLUSION: MHE is a common cause of ankle valgus in children. Guided growth interventions in this population can be successful but require special consideration given the potential for relatively gradual deformity correction and rapid recurrence following hardware removal in the skeletally immature.

LEVEL OF EVIDENCE: Level III, retrospective comparative study.