Early tibial loosening in the Attune total knee arthroplasty system: a retrieval analysis of clinical, demographic, and implant-related factors.

BACKGROUND: Early tibial loosening has been reported in the Attune total knee arthroplasty (TKA) system, with uncertainty regarding the contribution of clinical, demographic, and implant-related factors. METHODS: We retrospectively analyzed 130 retrieved Attune TKAs from 126 patients across nine institutions. Clinical and demographic data, reasons for revision, and implant features were collected. Cement coverage of 96 cemented tibial baseplates was quantified using digitized image analysis, and 15 polyethylene tibial bearings underwent mechanical and oxidation testing. Statistical significance was defined as p < 0.05. RESULTS: The mean time in situ was 2.0 years (range 0.1-8.3). Main reasons for revision were loosening (37.7%), infection (31.5%), and pain (23.1%). Male sex was associated with higher risk of infection (OR 3.44; 95% CI 1.53-7.75; p = 0.003), while female sex was associated with increased risk of aseptic loosening (OR 0.375; 95% CI 0.142-0.992; p = 0.048). Low cement coverage was significantly associated with aseptic loosening (p = 0.003). S+ baseplates demonstrated superior cement adhesion compared to the primary Attune baseplate (p = 0.001). Polyethylene bearings showed no evidence of oxidative degradation (average ketone index 0.47; no white banding observed). CONCLUSIONS: Aseptic tibial loosening in the Attune TKA system is significantly associated with poor cement adhesion, while the redesigned Attune S+ baseplate demonstrated improved cement coverage. No adverse polyethylene degradation was observed. These findings highlight the role of implant design and cement adhesion in early failure and underscore the value of retrieval analysis for improving TKA outcomes.