DISLOCATION AND SUBLUXATION DURING FEMORAL LENGTHENING

Femoral lengthening by callus distraction was performed on 26 femurs o f 18 patients with various disorders between 1988 and 1992. Age at sur gery ranged from 6 to 17 years (13 years on average). The amount of le ngthening varied from 2 to 7.5 cm (mean 5 cm). Follow-up evaluation of femoral-head displacement was based on the change of center-edge (CE) angle. The hips were divided into two groups based on the preoperativ e CE angle; one group consisted of 14 hips with a CE angle >20-degrees and the other group consisted of 12 hips with an angle of less-than-o r-equal-to 20-degrees. In the first group, none of the hips deteriorat ed; however, five of 12 hips in the second group did deteriorate. One hip developed complete dislocation and the other four showed a decreas e in the CE angle. Four of five deteriorated hips had a history of con genital dislocation of the hip and the other had multiple epiphyseal d ysplasia. In cases in which the CE angle is less-than-or-equal-to 20-d egrees preoperatively, bony procedures such as innominate osteotomy sh ould precede femoral elongation.