TEMPORAL TRENDS OF PRIMARY TOTAL HIP AND KNEE REPLACEMENTS IN THE TRENT REGION FROM 1991 THROUGH 2004

The aim of this study was to evaluate temporal trends in the prevalence of primary total hip and knee replacements (THR and TKR) throughout the Trent region from 1991 through 2004. The Trent Regional Arthroplasty Study (TRAS) records details of primary THR and TKR prospectively. TRAS data in conjunction with age-gender population data from the National Office of Statistics was used to quantify the rates of primary THR and TKR as a function of age (45–55, 56–65, 66–75, 76–85 and greater than 85 years), gender and diagnosis (osteoarthritis, rheumatoid arthritis and trauma). Poisson regression analysis was used to evaluate the procedural rate over time in primary THR and TKR as a function of age, gender and diagnosis. A total of 26,281 THR and 23,606 TKR were recorded during this period. The overall prevalence for primary THR did not change significantly over time (IRR = 1.0, 95% CI: 0.99 to 1.0, p = 0.875), whereas, the overall prevalence for primary TKR increased significantly by 2.5% during the fourteen year period (IRR = 1.025, 95% CI: 1.021 to 1.028, p The prevalence of primary TKR increased significantly over time whereas THR increased steadily in the Trent region between 1991 and 2004. These trends have important ramifications to the number of joint replacements expected to be performed in the future.