Lengthening of the ulna in radial agenesis: a preliminary report.

In two patients with bilateral radial agenesis, the ulnas were divided and lengthened in a modified Abbott-Anderson device with a gear box controlled by an electric motor to obtain from one to 2 mm. per day of gradual distraction. Three centimeters of length was achieved in 3 weeks. Bone bridged the gap in 3 months and was mature in 6 months. Repeat osteotomy and lengthening was done 12 to 18 months later. All secondary lengthening operations required bone grafts. Total length gained ranged from 5.4 to 6.4 cm.