Guided growth for ankle valgus.

BACKGROUND

Ankle valgus may be insidious and common in a variety of congenital conditions including clubfoot, neuromuscular disorders and others or acquired after fracture, osteotomies, or other manipulations of the lower extremity. This can cause hindfoot pronaton, resulting in lateral impingement and excessive shoe wear. Orthoses do not change the natural history. Medial hemiepiphysiodesis of the tibia is an accepted method of correcting this problem. Difficulties with transmalleolor screw removal prompted us to adopt the tension band method. Our purpose was to outline the technique of using guided growth with a medial tension band plate and discuss the efficacy of this technique.

METHODS

We undertook this retrospective review of 33 patients (57 ankles) who underwent guided growth to correct ankle valgus and were followed until attaining full correction or skeletal maturity. Most of the implants were removed when the ankle was neutral to 5 degrees of varus overcorrection. We obtained weightbearing anteroposterior radiographs of the ankles preoperatively, just before plate removal, and at final follow-up, measuring the lateral distal tibial angle and noting the fibular station. We documented the rate of correction and related complications.

RESULTS

The average age at surgery was 10.4 years (range, 6.1 to 14.6 y) and an average follow-up was 27 months (range, 12 to 57.5 mo). The lateral distal tibial angle improved from an average of 78.7 to 90 degrees at implant removal and measured 88.2 degrees at final follow-up. The rate of correction was calculated to be 0.6 degrees per month. The fibular station remained the same in 36 of 57 ankles and improved in 15 ankles. There were 2 cases of skin breakdown complicated by infection. There were no instances of hardware failure, excessive varus, or premature physeal closure and no patient has required an osteotomy.

CONCLUSIONS

Without appropriate radiographs, ankle valgus may be mistaken for hindfoot valgus and mismanaged accordingly. Guided growth of the distal medial tibia has become our treatment of choice for ankle valgus in the growing child or adolescent. Use of plate epiphysiodesis is safe, well tolerated, may readily be combined with other treatments, and provides a rate of correction comparable to the transmalleolar screw method.

LEVEL OF EVIDENCE: IV, retrospective review, no control series.