Cup-Cage Construct for Treatment of Severe Acetabular Bone Loss in Revision Total Hip Arthroplasty: Clinical and Radiographic Outcomes at a Mean Follow-Up of 7.7 Years

Background: Acetabular reconstruction in the context of massive acetabular bone loss is challenging. Achieving implant stability in these situations requires special considerations. The cup-cage construct is a treatment option that addresses this issue. This study evaluates survivorship, complications, and functional outcomes using the cup-cage construct.

Methods: A total of 131 cup-cage implants (129 patients) were identified from our retrospective review of revision total hip arthroplasties from January 2003 to January 2022. Among these cases, 100 (76.3%) were women, the mean age at the time of surgery was 68 years (range, 29 to 92; SD [SD], 12.4), and the mean follow-up was 7.7 years (range, 0.02 to 20.3; SD, 5.1). Kaplan-Meier survivorship analysis was conducted with failure defined as revision surgery and/or failure of the cup-cage reconstruction.

Results: At a mean follow-up of 7.7 years, the cup-cage construct survivorship due to all-cause failure was 83.9% (95% CI [confidence interval]: 77.6 to 90.2) at 5 years with 88 hips at risk, 74.8% (95% CI: 66.2 to 83.4) at 10 years with 38 hips at risk, and 69.8% (95% CI: 59.4 to 80.2) at 15 years with 11 hips at risk. The survivorship due to failure from aseptic loosening was 96.7% (95% CI: 93.6 to 99.8) at 5 years with 88 hips at risk and 95.5% (95% CI: 91.6 to 99.4) at 10 and 15 years with 38 and 11 hips at risk, respectively. The revision rate for aseptic loosening of the cup and/or cage, infection, dislocation, and aseptic loosening of the femoral stem was 5 of 131 (3.8%), 12 of 131 (9.1%), 10 of 131 (7.6%), and 2 of 131 (1.5%).

Conclusions: The cup-cage construct is a reliable treatment option for the treatment of various acetabular defects. There are favorable survivorship, clinical, and radiographic outcomes, with a satisfactory complication rate.