CAUSES OF REDISLOCATION AND RESUBLUXATION IN DEVELOPMENTALLY DISLOCATED HIPS TREATED BY THE SALTER’S INNOMINATE OSTEOTOMY

Abstract

Purpose: Causes of redislocation and resubluxation in developmental hip dislocations (DHD) treated by the Salter’s innominate osteotomy (SIO) were investigated.
Patients and methods: Between 1992-2000, 11 hips of 9 patients with developmental hip dislocation were reoperated due to redislocation or resubluxation. There were 2 males, 7 females, and the average age was 2.6 years (range, 20 months to 3.5 years).
Results: Varus-derotation osteotomy for correcting the excessive anteversion and valgus deformity of the femur in 4 (36%) hips, a varus osteotomy for correcting the valgus deformity in 1 (9%) hip, derotation osteotomy for correcting the excessive femoral anteversion in 3 (27%) hips and open reduction with capsulorrhaphy for lessening the laxity of the capsule in 2 (18%) hips, were performed. A posterior displacement developed again in one hip in which a SIO with an additional femoral derotation osteotomy had been performed. In this case, a reverse derotation osteotomy was performed.
Discussion: Redislocation or resubluxation can develop as a complication after the treatment by the SIO in developmental hip dislocations. To prevent these complications, the excessive femoral anteversion (45° !), valgus deformity (150° !) and the laxity of the capsule should be avoided. The acetabular and femoral anteversion angles may be measured by computed tomography. If these angles are excessive, femoral derotation and varus osteotomies must be performed. A firm capsulorraphy should not be neglected. As the SIO lessens the degree of acetabular anteversion, femoral derotation osteotomy must be performed carefully in the hips having not excessive acetabular anteversion. If the femoral anteversion angle decreases markedly due to femoral derotation osteotomy, in these cases a posterior dislocation may develop.