Low Risk of Cup Fixation Failure at 10 Years Using Constrained Liners at the Same Time of Acetabular Component Revision.

Abstract

There remains concern regarding simultaneous constrained liner (CL) implantation during acetabular component revision in revision total hip arthroplasty due to potential fixation loss at the bone-implant interface. There are scarce long-term data on this technique. This study aimed to determine the survivorship free from aseptic cup loosening (fixation failure) and all-cause re-revision when CLs were implanted concurrently with acetabular cup revision. We retrospectively identified all revision total hip arthroplasties where CLs were implanted simultaneously with acetabular cup revision at our institution between 2001 and 2021. We included 174 revisions with a mean follow-up of 8.7 years (range, 2 to 21.7). The mean age was 70 years, and 60.9% were women. There were 10% that had Paprosky type I bone loss, 68.4% had type IIA-C, and 21.3% had type IIIA-B. The main indications for index acetabular revision were instability (35%), second-stage reimplantation (26.4%), and loosening (17.2%). Only 25% of revisions used modern, highly porous revision shells. There were two-thirds of the CLs manufactured by one implant company and one-third by another. There were 23 (13%) cemented CLs. Screw fixation was evaluated. Kaplan-Meier survival was determined with revision for cup aseptic loosening and all-cause re-revision as endpoints. There were 32 (18.3%) patients who underwent re-revision at a mean of 2.9 years (range, 0.1 to 14.1). The most common reason for re-revision was instability (14). There were three (1.7%) that required re-revision for acetabular component fixation failure. Acetabular component survival free from re-revision due to fixation failure was 98.9% at 5 years and 98.1% at 10 years. The all-cause re-revision-free survival was 84.9% at 5 years and 79.9% at 10 years. Implanting CLs during acetabular component revision with stable fixation is safe with a very low risk of cup fixation failure. There were no cup fixation failures in highly porous shells.