Declining Complications After Primary Total Knee Arthroplasty Over 16 Years

Demand for primary total knee arthroplasty (TKA) continues to rise, but contemporary temporal changes in 90-day and 2-year complication risk across multiple outcomes remain incompletely defined.

Adults undergoing primary TKA for knee osteoarthritis from 2008 through 2023 were identified in a large national database using Current Procedural Terminology (CPT) 27447 with an antecedent or same-day knee osteoarthritis diagnosis. Patients who had a previous or revision TKA, periarticular fracture, or bone/articular cartilage malignancy before index were excluded. Annual risks were assessed for eight 90-day and seven 2-year outcomes. Trends were modeled with grouped binomial logistic regressions and reported as odds ratios (OR) per 5-year calendar increase.

The cohort included 201,736 patients, with captured annual volume increasing from 1,086 to 33,775. The mean age increased from 65 to 68 years, and the proportion of women decreased from 63.2 to 60.3%. A total of seven 90-day outcomes declined, including periprosthetic joint infection (PJI) (1.20 to 0.73%; OR 0.78, 95% confidence interval (CI) 0.73 to 0.83), deep vein thrombosis (2.49 to 1.61%; OR 0.73, 95% CI 0.70 to 0.76), and transfusion (8.38 to 6.30%; OR 0.50, 95% CI 0.49 to 0.51), while sepsis was unchanged. At two years, revision/reoperation, PJI, aseptic loosening, mechanical complications, implant-related complications, and manipulation under anesthesia declined; periprosthetic fracture remained stable.

From 2008 through 2023, 90-day and 2-year complication risks after primary TKA declined across nearly all assessed outcomes despite cohort aging and marked growth in captured procedures. These findings provide contemporary network-based benchmarks for primary TKA outcomes.