FIBULAR HEMIMELIA: GUIDELINES FOR TREATMENT BASED ON A NEW CLASSIFICATION

Abstract

Amputation vs. limb salvage in FH has been based on fibular presence or absence and a ‘good’ or ‘bad’ foot. None of the current FH classification systems address ankle joint, hindfoot and forefoot morphology. We present a new, comprehensive FH classification which delineates leg, ankle and foot morphology. Three major groups are proposed; I-mild fibular shortening; II-small or miniature fibula; III-absent fibula. Ankle mortise morphology is defined as H=horizontal; S=spherical; V=valgus. A small “c” denotes a tarsal coalition. Numerals 1–5 reflect the number of forefoot rays present. For example, a patient with a miniature fibula, valgus ankle, tarsal coalition and 4 rays would be classified as II Vc4.

Thirty-two limbs in 31 FH patients were assessed by teleoroentgenograms, weight-bearing ankle and foot radiographs and examination. All had shortened femora, the amount of which did not correlate with fibular type. Type III fibulae were highly associated with valgus ankles (56%), decreased number of rays (46–100%), and tarsal coalition (69%). Coalition was found in all ray categories but diminished number of rays (42–100%) with associated valgus ankles (68%) correlated strongly with a coalition. In patients with type III fibulae, one-third had horizontal ankles, 53% had 4 or 5 rayed feet and 30% had no coalition. Fibular absence did not correlate with percent tibial shortening or ankle valgus.

We present a reproducible classification which reflects the spectrum of ankle and foot involvement seen in review of 32 FH cases. Early amputation is recommended for limbs with fewer than 3 rays. Twenty-seven patients underwent limb reconstruction and 4 had ankle disarticulation and required adjunctive bony and soft tissue procedures. Extension of the fixation to the foot should be done during tibial lengthening in FH.