TRENDS IN BILATERAL TOTAL KNEE REPLACEMENT IN THE UNITED STATES. BETWEEN 1990 AND 2004: ANALYSIS OF 153,259 PATIENTS

Abstract

Introduction: There is scant information on the trends of simultaneous bilateral total knee arthroplasties (BTKA). The safety of BTKR has been put into question because of a possible association with increased morbidity and mortality. We hypothesized that substantial changes in BTKA patients demographics, in-hospital complications and mortality have occurred over time in the United States.

Methods: We analyzed information collected for the National Hospital Discharge Survey (NHDS) from 1990 to 2004, to elucidate temporal changes in the utilization, demographics, comorbidity profiles, hospital stay, and in-hospital complications of patients undergoing BTKA in the United States. Three five-year periods were created (1990–1994, 1995–1999, 2000–2004) to facilitate temporal analysis. Temporal changes in patient and health care variables were analyzed.

Results: 153,259 discharges after BTKR were identified (20.18% performed between 1990 and 1994, 28.73% between 1995 and 1999 and 51.08% between 2000 and 2004). Utilization of BTKR more than doubled for the entire civilian population and almost tripled among females. All age groups experienced an increase in utilization of BTKR throughout the study period, except those 85 and older. Most recently a decline of approximately 50% was seen. The distribution of BTKR procedures among age groups changed significantly, with an increased proportion of patients between the ages of 45–64 receiving this procedure (32.83% in 1990–1994; 43.62% in 2000–2004). Comorbidity burden increased steadily over time for hypertension, diabetes mellitus, hypercholesteremia, obesity and renal disease, with half of all patients being affected by hypertension in the most recent time period. The prevalence of coronary artery disease and pulmonary disease decreased from the second to the third time period. Length of hospital stay decreased by half from 9.27 (range 2–53) days between 1990–1994 to 5.44 (range 1–44) days between 1995–1999 and to 4.68 (range 1–33) days between 2000–2004. Overall, procedure related complications rates decreased over time from 19.85% in the first time period to 8.89% in the most recent time period studied.

Discussion: We identified a number temporal changes associated with BTKR performed during the same hospitalization. While utilization in general increased over time, operations on patients above the age of 85 years and amongst those with cardiac and pulmonary disease decreased during the last decade. Overall, procedure related complication rates fell by approximately 50% over the study period.