Failure of bulk bone grafts after total hip arthroplasty for hip dysplasia.

Introduction: Bulk bone grafts are used in total hip arthroplasty (THA) when adequate acetabular cup coverage cannot be achieved. Data from literature show mainly good short-term and mid-term results with contradictory long-term results. The aim of this study was to investigate acetabular cup stability and graft integrity after dysplastic adult hip reconstruction with total hip endoprosthesis and bulk bone graft for acetabular deficiency.

Methods: Seventy-two hips in 64 patients that underwent THA with bone autograft or allograft were assessed immediately after operation, 6 months and 1, 2, 3 and 10 years after operation. Acetabular angle, acetabular cup coverage, bone graft width, and bone graft height were measured and questionnaire was designed to determine acetabular cup stability and grade graft integrity. Four investigators graded grafts and inter-rater and intra-rater reliability of the questionnaire was tested.

Results: All measured parameters in all patients and in patients with autograft and those with allograft separately showed significant changes consistent with graft failure and acetabular cup instability when level of significance was set at p < 0.05.

Conclusions: Results of this study show significant decrease in acetabular cup stability when either autograft or allograft is used for cemented acetabular reconstruction of dysplastic hip. Further, allografts showed twice as rapid failure as autografts. Although these results contradict both good short-term and long-term results in published literature, they present warning for future use of free bulk bone grafts in reconstructive hip surgery.