Minimum Five-Year Outcomes of Cemented Monobloc Dual-Mobility Cups in Revision Total Hip Arthroplasty: High Survival Rates and Enhanced Functional Results With Reinforcement Constructs.

BACKGROUND

Monobloc dual-mobility cups (MDMCs) significantly reduce the risk of dislocations, a major complication in revision total hip arthroplasty (RTHA). In RTHA, cementing the acetabular cup may be required, particularly when combined with an acetabular reinforcement. This study aimed to evaluate the survivorship of cemented MDMC in reinforcement constructs in RTHA.

METHODS

During a 10-year period, we retrospectively evaluated 59 patients undergoing RTHA with a cemented MDMC combined with an acetabular reinforcement construct, with a minimum follow-up of 5 years. The mean age at surgery was 69 years, the mean body mass index was 26.1, and 63.3% were women. Preoperative Harris Hip Score (HHS), indication for revision, and the type of acetabular reconstruction were recorded. Postoperatively, complications and revisions were evaluated. Failure was defined as implant revision, whereas the HHS was assessed at the final (mean 5.8 years) follow-up.

RESULTS

There were 10 failures observed (16.9%): six for periprosthetic joint infection (10.2%), three for acetabular aseptic loosening (5.1%), and one for dislocation (1.7%). The 5-year implant survival for any revision was 83.1% (95% confidence interval [CI]: 70.8 to 90.5), and for septic revision was 89.8% (95% CI: 78.8 to 95.3). and for mechanical failure was 93.2% (95% CI: 82.9 to 97.4). The mean time interval between index surgery and revision was 9.9 months. At the final follow-up, the mean HHS was 82.7 (range, 37 to 100).

CONCLUSIONS

The use of cemented MDMCs combined with acetabular reinforcement in RTHA seems to be an effective approach for achieving favorable functional outcomes, with a low risk of dislocation or mechanical failure at midterm (mean 5.8 years) follow-up.

LEVEL OF EVIDENCE

Retrospective, consecutive case series; level III.