Impaction Grafting Is Sufficient to Address Acetabular Deficiency During Total Hip Arthroplasty of Most Dysplastic Hips With Over 30% Bone Defect.

Background: Addressing acetabular deficiency during arthroplasty of dysplastic hips is challenging. We assessed outcomes of a protocol for choosing either impaction or structural graft for this purpose.

Methods: This retrospective study included 59 patients (71 hips) with a dysplastic hip and over 30% uncoverage that underwent cementless total hip arthroplasty. Morselized impaction grafting was performed for hips where initial stability of the acetabular cup was achieved. In others, a shelf graft was inserted before implantation of the acetabular cup. Outcomes were assessed at a minimum follow-up of 4 years.

Results: Fifty-seven (80.3%) hips underwent impaction grafting and 14 (19.7%) received a structural graft. Mean age at surgery was 48.1 ± 13.5 (18-68) years for impaction and 48.6 ± 14 (24-70) years for shelf grafts. Mean increase in Harris Hip Score was 51.5 ± 9.3 and 50 ± 11.2 for the impaction and structural groups, respectively, at a mean follow-up of 92 (49-136) months (P = .6). Heterotopic ossification occurred in 16 patients in the impaction group vs none in the structural group (P = .004). Radiologically, mean percentages of cup coverage provided by the graft were 47.8 ± 10.9% and 48.9 ± 13.3% in the impaction and structural groups, respectively (P = .75). All but one of shelf grafts united to host bone and all impaction grafts incorporated. There was one case of cup loosening in the structural graft group.

Conclusion: Most dysplastic acetabula with over 30% defect can be addressed using a cementless cup and impaction grafting, with good results in the midterm. In about 20% of cases, initial press-fit is not attainable and structural support-like shelf graft becomes necessary.

Level Of Evidence: IV.