VARIABLES AFFECTING TIME TO BONE HEALING DURING LIMB LENGTHENING

Radiographs and charts of 114 consecutive patients who underwent 140 l ower-extremity bone-segment lengthening procedures using the Ilizarov external fixator were reviewed. Patient age, bone segment (femur, tibi a), corticotomy level(metaphyseal, diaphyseal, double level), and dist raction gap (DG) were recorded. Distraction-consolidation time (DCT) w as defined as the interval in months from the date of the corticotomy until the DG was healed according to radiographic and manual testing c riteria. Distraction-consolidation time had a direct linear relationsh ip with the magnitude of the DG. Distraction-consolidation time versus DG was significantly less for femoral than tibial lengthening. Patien ts 20 years and older healed slower than patients younger than the age of 20 years. Patients 20 to 29 years old healed faster than patients older than 30 years and slower than patients younger than 20 years. Di aphyseal lengthening healed more slowly than metaphyseal lengthening. Double-level lengthening reduced the DCT when the DG was greater than 4 cm. Distraction-consolidation index-DCT divided by DG-was not a cons tant. Distraction-consolidation index decreased with increasing DG. To facilitate prediction of bone-healing time, graphs were developed dem onstrating the average treatment time +/- 2 SD expected for a specific amount of lengthening, considering the bone segment, the level of ost eotomy, and the age of the patient.