Lengthening of the humerus is now an established
technique. We compared the complications of humeral lengthening
with those of femoral lengthening and investigated whether or not
the callus formation in the humerus proceeds at a higher rate than
that in the femur. A total of 24 humeral and 24 femoral lengthenings
were performed on 12 patients with achondroplasia. We measured the
pixel value ratio (PVR) of the lengthened area on radiographs and
each radiograph was analysed for the shape, type and density of
the callus. The quality of life (QOL) of the patients after humeral
lengthening was compared with that prior to surgery. The complication
rate per segment of humerus and femur was 0.87% and 1.37%, respectively.
In the humerus the PVR was significantly higher than that of the
femur. Lower limbs were associated with an increased incidence of
concave, lateral and central callus shapes. Humeral lengthening
had a lower complication rate than lower-limb lengthening, and QOL
increased significantly after humeral lengthening. Callus formation
in the humerus during the distraction period proceeded at a significantly
higher rate than that in the femur. These findings indicate that humeral lengthening has an important
role in the management of patients with achondroplasia.