Reliability of the acetabular reconstruction technique using autogenous bone graft from resected femoral head in hip dysplasia: Influence of the change of hip joint center on clinical outcome.

Introduction: The previous studies have not reached on consensus as to the outcome of acetabular reconstruction with autogenous bone graft for dysplastic hips, especially in severe cases such as Crowe type IV. The current study aimed to determine the survivorship of the arthroplasty and the grafts as well as the change of hip joint center averagely 9.8 years (range, 5-19) after cementless total hip arthroplasty.

Materials And Methods: We reviewed 52 cases including 19 cases of complete hip dislocation of which acetabular defects were augmented with autogenous bone grafts taken from the resected femoral heads. For radiographic evaluation, in addition to checking failures of THA, acetabular coverages of the grafts as well as lateral center-edge angles were measured and compared between two time points, immediately postoperative and the final evaluations. Those outcomes were also analyzed according to the degree of hip dysplasia, grouping the subjects by Crowe classification. Translations of the reconstructed hip joint center after THA were measured and checked if they affected clinical outcomes or caused any complications. To assess clinically, Harris hip score and visualized analogue pain scale were reviewed.

Results: Mean coverage ratio of the sockets with the grafts was 28.4% immediately after the surgery (range, 11.1%-65.0%) and 27.2% at the final follow-up (range, 11.1%-63.6%). When comparing high grade dysplasia (Crowe type III, IV) to low grade dysplasia (Crowe type I, II), there was no significant difference of the above outcomes (p = 0.476). As to the location of hip joint center, 14 outliers were located distally within the normal horizontal range especially in cases with Crowe type IV. Those outliers showed no difference on clinical outcome. The mean HHS was 52.2 (range, 19-87) and VAS was 7.2 (range, 5-9) preoperatively, each of which was improved to 92.9 (range, 63-100) and 1.4 (range, 0-4) postoperatively. No failures were experienced during the study period.

Conclusions: Acetabular augmentation using autogenous bone graft from the resected femoral head is found to be a successful method for dysplastic hip, even in severe cases such as Crowe type IV, showing favorable results in more than 8 years. When inevitable, a degree of compromise on hip joint center can be needed in dealing with severe hip dysplasia.