Changes in knee motion following femoral and tibial lengthening using the Ilizarov apparatus: a cohort study.

We studied 46 patients undergoing tibial or femoral lengthening to correct limb-length discrepancy (LLD) to assess the effects of the procedure on the range of motion (ROM) of the knee. The ROM of the knee has decreased even before the lengthening process started, and was at its most pronounced by the end of the lengthening. Mean preoperative ROM was 125 degrees +/- 21 degrees, and at follow-up, at an average of 41 +/- 7.8 months from the beginning of the lengthening procedure, mean ROM was 117 degrees +/- 25 degrees (P = 0.31). There was no association between the worst ROM achieved during lengthening and the final ROM. Femoral lengthening resulted in a significantly greater loss of ROM for longer periods than tibial lengthening. Patients with congenital LLD were at risk of faster, more permanent loss of ROM than patients with posttraumatic or postinfective LLD. After the removal of the tibial or femoral Ilizarov frames, the ROM of the knee tended to return to prelengthening values.