Bone growth following lengthening for congenital shortening of the lower limb.

Bone and limb growth velocity ratios were studied in patients undergoing lengthening for unilateral congenital shortening of the lower limb. In 15 patients before lengthening, the length ratio (LR) between the normal and short sides remained constant with age. Consequently, the growth velocity ratio (GVR) between the normal and short sides also remained constant and equal to the LR. In 20 children, no significant change in GVR was observed after lengthening was carried out at a mean age of 9.6 years. Our results suggest that final limb length remains reasonably predictable and that an acceptable discrepancy can be expected, especially following lengthening after age 9 years.