Bilateral humeral lengthening in achondroplasia.

Twenty humeral lengthenings were done on 10 achondroplastic dwarfs using the Ilizarov circular fixator. There were five female and five male patients from 6 years 11 months to 17 years 8 months of age (mean, 12 years 10 months) at the time of the operation. Mean length obtained was 7.8 cm (range, 3.5 cm-10 cm). External fixation time ranged from 105 days to 368 days (mean, 221 days). Healing index averaged 30 days/cm (27 days/cm when two patients with radial nerve palsy were excluded). Two half pins in one patient required replacement. Two humeral fractures occurred, one while in the fixator and the other after removal of the apparatus. Transient radial nerve palsy developed during lengthening in two patients, and lengthening was discontinued. Symptoms of radial nerve palsy resolved completely in both patients, but one patient required an additional surgery to explore the radial nerve for persistent paresthesia of the forearm. Although preexisting loose shoulders deteriorate during lengthening and sometimes cause pain and discomfort, they always resolve spontaneously as lengthening proceeds. Bilateral humeral lengthening was very effective for improving function and overall proportion in patients with achondroplasia.