Recurrence of Ankle Deformity Following Reconstruction in Patients With Fibular Hemimelia and Dynamic Valgus

Dynamic valgus of the ankle and subtalar joint occurs in patients with fibular hemimelia and a hypoplastic distal fibula. The purpose of this study is to relate clinical dynamic valgus to radiographic measurements and to radiographically evaluate the shortening osteotomy for realignment of the distal tibia (ShORDT) for treatment of this condition.

A retrospective study was conducted on patients with fibular hemimelia who underwent the ShORDT procedure. Radiographic measurements included: lateral distal tibial angle (LDTA), talocrural angle (TCA), anterior distal tibial angle (ADTA), and distal fibular station (DFS). Logistic regression was performed to determine if any measurements could predict dynamic valgus. Measurements were compared at different time intervals. Linear regression was performed to determine if age, follow-up duration, or a synostosis/tether were related to changes in DFS following surgery.

Twenty patients met the inclusion criteria (9 females/11 males). The mean age at surgery was 6.9 years (±3.5 y) with a mean follow-up of 4.0 years (±1.3 y). Logistic regression found DFS ( P <0.001) to be predictive of dynamic valgus. DFS demonstrated a significant improvement from preoperative to postoperative measurements ( P <0.001), recurrence from postoperative to final ( P <0.001), and no difference between the preoperative and final values ( P =1.00). Linear regression found that a synostosis/tether ( P <0.001) and follow-up duration ( P =0.02) were predictive of change in DFS postoperatively.

DFS is a reproducible radiographic measurement in patients with fibular hemimelia to radiographically confirm dynamic valgus. In general, the deformity correction achieved recurs in the growing patient. Use of a solid tether or synostosis between the tibia and fibula may mitigate the recurrence.

Level III-Retrospective cohort study.