Long-term results of the Burch-Schneider antiprotrusio cage: a single-centre follow-up of 144 cases after a minimum of 5 years.

Background: Although the Burch-Schneider antiprotrusio cage (BS-APC) has been reported to be reliable, long-term data for this implant are scarce. We thus aimed to investigate survival and radiological results for revision total hip arthroplasty with the BS-APC in patients with major bone deficiency (55% AAOS defect grade 3, 39% grade 4) who had a minimum follow-up of 5 years (mean 10.2 years).

Methods: 144 revisions in 140 patients were performed due to aseptic loosening (n = 74), infection (n = 50), or other reasons (n = 20). Survival analysis was performed with death as a competing risk. Clinical follow-up was performed at 1, 2, and 5 years and every 5 years thereafter.

Results: 77 patients died during follow-up, 25 within the first 5 years. 12 BS-APCs were re-revised for infection (n = 5), aseptic loosening (n = 5), or instability (n = 2). The cumulative incidence for aseptic re-revision of BS-APCs was 4.3% at 10 years (95% CI, 1.8-10.1%), and the cumulative risk of death was 73.3% (95% CI, 62.4-83.2%). Radiological changes occurred in 26 of 87 radiologically examined hips, of which 8 cases were revised.

Conclusions: We found excellent mid- and long-term survival of the BS-APC in acetabular revision with major bone deficiencies, in accordance with or superior to most literature reports, which might be explained by strict adherence to surgical technique.