Trends in Polyethylene Design and Manufacturing Characteristics for Total Knee Arthroplasty: an Analysis From the American Joint Replacement Registry.

BACKGROUND Advances in polyethylene bearing characteristics have led to various options for total knee arthroplasty (TKA). We examine trends in use of polyethylene in the United States. METHODS An analysis of American Joint Replacement Registry (AJRR) data from 2012-2019 for primary TKA procedures. Design and manufacturing characteristics were obtained and validated in the AJRR dataset. Polyethylene bearing design and manufacturing use characteristics were compared by year, gender, age group and geographic region of the procedure. Descriptive analysis was performed. RESULTS We identified 993,292 cases over the study period. 791,233 (80%) of cases had complete device data available and were included in analysis. 366,280 (49.4%) utilized minimally stabilized bearings compared to 374,809 (50.6%) for posterior stabilized (PS). PS use was stable over the study period and highest in the northeast 64.5% (p<0.0001). Cruciate retaining (CR) use decreased from 29.7% to 20.2% and anterior stabilized (AS) use increased from 17.4% to 25.2%. Conventional polyethylene use decreased from 42.8% to 21.9%, and was highest in the 81+ age group 37.8% (p<0.0001), and northeast 43.0% (p<0.0001). Highly cross-linked polyethylene (HXLPE) with antioxidant use increased from 9.08% to 31.8%, while HXLPE without antioxidant use remained constant. CONCLUSION There was an increase in use of AS and Pivot Bearings and an increase in use of HXLPE with antioxidant. Additionally, there were noted age group and regional differences in the use of various bearings. Further study should evaluate if these changing utilization trends are related to clinical outcomes, or due to regional training, preferences or manufacturer pressures. LEVEL OF EVIDENCE Level III, retrospective.