Hip dislocation during lengthening of congenital short femur.

Hip dislocation is a serious but rarely reported complication of femoral lengthening in congenital short femora. We report a retrospective series of three hip dislocations that occurred during lengthening, analyze the factors contributing to the dislocation, and discuss the treatment of this difficult problem. The average lengthening achieved was 9 cm. We found progressive acetabular dysplasia and decreasing center edge angle. Closed reduction failed. Treatment included soft tissue release, open reduction with femoral shortening, and acetabular procedures. At a mean follow-up of 4.4 years, two patients had a good modified Mckay score and a modified Severin score of 3. Excessive lengthening should be avoided.