Utilization and Short-Term Outcomes of Primary Total Hip and Knee Arthroplasty in the United States and Canada An Analysis of New York and Ontario Administrative Data

Objective. Total knee arthroplasty (TKA) and total hip arthroplasty (THA) are common and effective surgical procedures. This study sought to compare utilization and short-term outcomes of primary TKA and THA in adjacent regions of Canada and the United States. Methods. The study was designed as a retrospective cohort study of patients who underwent primary TKA or THA, comparing administrative data from New York and Ontario in 2012-2013. Demographic features of the TKA and THA patients, per capita utilization rates, and short-term outcomes were compared between the jurisdictions. Results. A higher percentage of New York hospitals performed TKA compared to Ontario hospitals (75.7% versus 42.1%; P < 0.001), and the mean annual procedural volume for TKAs was lower in New York hospitals (mean 179 versus 327 in Ontario hospitals; P < 0.001). After direct standardization, utilization was significantly lower in New York compared to Ontario, both for TKA (16.1 TKAs versus 21.4 TKAs per 10,000 population per year; P < 0.001) and for THA (10.5 THAs versus 11.5 THAs per 10,000 population per year; P < 0.001). For those who underwent TKA, the length of stay in Ontario hospitals was significantly longer (mean 3.7 days versus 3.4 days in New York hospitals; P < 0.001). A smaller percentage of New York patients were discharged directly home (46.2% versus 90.9% of Ontario patients; P < 0.001), but 30-day and 90-day readmission rates were higher in New York compared to Ontario (30-day rates, 4.6% versus 3.9% [P < 0.001]; 90-day rates, 8.4% versus 6.7% [P < 0.001]). For the THA cohorts, the results with regard to length of stay, discharge disposition, and readmission rates were similar to those for TKA. Conclusion. Ontario has higher utilization of total joint arthroplasty than New York but has a smaller percentage of hospitals performing these procedures. Patients are more likely to be discharged home and less likely to be readmitted in Ontario. Our results suggest areas where each jurisdiction could improve.