Postaxial hypoplasia of the lower extremity.

Congenital deficiency of the fibula may present a variety of patterns. In a series of 20 patients with this diagnosis, we have observed limb-length inequality and a spectrum of musculoskeletal anomalies involving the ipsilateral hip, femur, knee, tibia/fibula, ankle, and foot. Considering the frequently associated abnormalities of the lower extremity, the term postaxial hypoplasia may be more descriptive than the traditional terms fibular hemimelia or fibular a/hypoplasia. By raising the awareness of associated deformities, the clinician is better prepared to advise patients and to intercede accordingly. Based on our experience, we advocate a modular treatment approach combining limb lengthening with hemiepiphysiodesis of the distal femur and/or ankle to correct valgus alignment and establish a neutral mechanical axis. Contralateral epiphysiodesis as an adjunct may be preferable to double or repeated lengthening. The goal is to achieve symmetry and stable joints at skeletal maturity with a minimal number of well-timed surgical interventions. By using this strategy and with minimal morbidity, 10 of our patients who have reached skeletal maturity have achieved a satisfactory outcome.