Simultaneous bilateral lengthening of femora and tibiae in achondroplastic patients

The aim of this study was to analyze the results and complications of simultaneous bilateral femoral and tibial lengthening in achondroplastic patients.

The study included the 44 femora and 44 tibiae of 22 achondroplastic patients (16 females, 6 males; mean age: 6.36 years, range: 3 to 11 years) that underwent simultaneous lengthening. Orthofix LRS monolateral fixators were used for femoral lengthening and either Ilizarov-type or hexapod-type circular external fixators for tibial lengthening. Tenotomies of the hip flexors and the Achilles tendon were performed to prevent injury to the growth plates and to prevent joint contractures. Results and complications were evaluated according to Paley's scoring and complication systems.

Average follow-up time was 35 (range: 26 to 76) months. The femora were lengthened by an average of 7.07 cm (46.1%), and the tibiae by an average of 6.64 cm (52.9%). Patients gained an average of 16.9 cm in height, including physiological growth. The mean bone-healing index (BHI) was 31.2 days/cm for the femora (range: 17.4 to 43.3 days/cm) and 34.3 days/cm for the tibiae (range: 19.5 to 60.0 days/cm). Complications included 3 delayed maturations, 3 pin track infections, 5 transient fibular paralyses, 5 regenerate fractures, 1 late varus deformity, 1 knee contracture and 1 knee contracture secondary to knee dislocation. Functional scores were excellent in 78 segments, good in 8, fair in 1 and poor in one. There was no growth inhibition related to the lengthening.

Bilateral simultaneous lengthening of the femora and tibiae in achondroplastic patients provided a reduction in total treatment and external fixation time, with a low rate of complications.