OBJECTIVES: The primary objective of this study is to estimate the number of hip/knee replacements performed in the nation as well as to produce synthetically derived estimates for Ohio. These estimates were then used for the estimation of the economic burden associated with these arthritis related surgeries. METHODS: The 2000 National Hospital Discharge Survey (NHDS) was utilized to estimate the number of hip/knee replacements performed in the nation. The ICD-9-CM procedure codes used to identify patients are ICD-9-CM 81.51 (total hip replacement) and 81.54 (Total/partial knee replacement). The NHDS recorded up to four ICD-9-CM procedures for each discharge. Since the main purpose of this study was to estimate the burden of arthritis-related surgeries, all four procedures recorded for each patient were considered for the identification of arthritis-related surgery. Then, the total number of hip/knee replacements in Ohio was estimated by applying age and sex distributions based on the U.S. census 2000. Since the NHDS does not include cost information on hospital discharges, diagnosis related group (DRG) reimbursement was used to approximate the total hospital charges. RESULTS: In the United States, approximately 9.6 billion dollars were used for 439,833 hip and knee replacement surgeries in the year 2000. In Ohio, approximately 407 million dollars were spent for 18,731 hip and knee replacement surgeries. CONCLUSIONS: The estimated cost for joint replacements alone was nearly $10 billion in the United States during the year 2000. The total cost of joint replacements will be much higher if we include pre and post-operation care.