Stemmed acetabular cup as a salvage implant for revision total hip arthroplasty with Paprosky type IIIA and IIIB acetabular bone loss.

Introduction: Certain cases of repeated acetabular loosening with severe bone loss are hardly amenable to reconstruction using a Kerboull-type plate with allograft. This limitation is more likely when the severe bone loss occurs in older adults with significant comorbidities that may require a faster procedure. In these indications, a stemmed acetabular cup may be an alternative, although the outcomes have not been well defined, especially for a version where the peg is coated with porous material and additional screws can be added. This led us to conduct a retrospective study to determine: (1) whether a stemmed cup anchored in the iliac isthmus is a viable alternative in these situations, (2) the complication rate and (3) the revision rate for any reason.

Hypothesis: A stemmed cup anchored in the iliac isthmus is a viable alternative in cases of repeated revision with severe acetabular bone loss.

Materials And Methods: We performed a retrospective single-center study. Sixteen Integra™ cups were implanted in 14 patients (mean age 72.8±10.4 years, minimum-maximum: 58-95) who had aseptic acetabular loosening combined with severe acetabular bone loss graded as Paprosky IIIA in 7 hips and IIIB in 9 hips. The patients had undergone a mean of 2.7±1.8 (minimum-maximum: 1-6) procedures (i.e. primary and/or revision arthroplasty) before this cup was implanted. The cup's survivorship at the time of review and the complication rate were determined.

Results: At a mean follow-up of 48.8±23.4 months (minimum-maximum: 7-85), two patients had died and two were lost to follow-up. Six hips experienced one or more complications (37.5%): three infections (18.8%), two mechanical failures (12.5%) and one dislocation (6.7%). The cup had to be removed in three patients (18.8%). These complications required reoperation, thus the cumulative incidence of revision for any reason at 5 years was 31% (95% CI: 11-55%).

Conclusion: Despite the high complication and revision rates, we believe the stemmed acetabular cup is a viable alternative in salvage reconstruction procedures.

Level Of Evidence: IV, Retrospective case study.