Valgus extension osteotomy for 'hinge abduction' in Perthes' disease. Results at maturity and factors influencing the radiological outcome.

Valgus extension osteotomy (VGEO) is a salvage procedure for 'hinge abduction' in Perthes' disease. The indications for its use are pain and fixed deformity. Our study shows the clinical results at maturity of VGEO carried out in 48 children (51 hips) and the factors which influence subsequent remodelling of the hip. After a mean follow-up of ten years, total hip replacement has been carried out in four patients and arthrodesis in one. The average Iowa Hip Score in the remainder was 86 (54 to 100). Favourable remodelling of the femoral head was seen in 12 hips. This was associated with three factors at surgery; younger age (p = 0.009), the phase of reossification (p = 0.05) and an open triradiate cartilage (p = 0.0007). Our study has shown that, in the short term, VGEO relieves pain and corrects deformity; as growth proceeds it may produce useful remodelling in this worst affected subgroup of children with Perthes' disease.