Cement Viscosity Is Associated With Aseptic Loosening After Primary Total Knee Arthroplasty: An Analysis of the American Joint Replacement Registry.

BACKGROUND: The mechanical properties of polymethylmethacrylate (PMMA) cement in total knee arthroplasty (TKA) can be influenced by both viscosity and the addition of antibiotics. Although smaller studies have reported high survivorship with commercially available formulations of PMMA in primary TKA, the independent and combined effects of viscosity and antibiotic additives on revision risk remain subject to debate.

METHODS: A retrospective analysis was performed using data from the American Joint Replacement Registry (AJRR) for all patients undergoing primary cemented TKA between 2012 and 2022 in patients ≥ 65 years old. Patients were categorized by cement type (antibiotic versus non-antibiotic) and viscosity (low-, medium-, or high-viscosity cement (LVC/MVC/HVC)). Cox proportional hazards models were used to evaluate the risk of revision surgery, adjusting for multiple factors, including cement viscosity and antibiotic use.

RESULTS: A total of 233,841 TKAs were included. Both HVC and MVC had significantly higher cumulative percent revision for aseptic loosening compared with LVC, while MVC had the highest rate of aseptic loosening (HR [hazard ratio] 2.32, 95% CI [confidence interval] 1.89 to 2.85). Antibiotic cement was used in 81,462 cases (35%). Compared with non-antibiotic cement, antibiotic cement was not associated with a difference in revision for aseptic loosening or periprosthetic joint infection (PJI).

CONCLUSIONS: In a large national cohort of patients undergoing primary TKA, MVC demonstrated consistently higher risk of aseptic loosening compared with both LVC and HVC. Antibiotic cement use was not associated with an increased risk of revision for aseptic loosening or reduction in PJI.