The Journal of Arthroplasty, Volume 32, Issue 8, 2339 - 2346

Is Day of Surgery Associated With Adverse Clinical and Economic Outcomes Following Primary Total Knee Arthroplasty?

Boylan, Matthew R. et al.


As orthopedics transition to value-based purchasing, hospitals and providers are incentivized to identify inefficiencies of care delivery. In our experience, weekends are characterized by decreased staffing of ancillary services to coordinate patient discharges, which can lead to prolonged hospital stays for many of our primary total knee arthroplasty (TKA) admissions.


We identified 115,053 patients who underwent primary TKA on a weekday between 2009 and 2013 in New York State. We used mixed effects regression models to compare length of stay (LOS), 90-day readmission, and cost according to the day of TKA.


Mean LOS was significantly higher for surgeries performed on Wednesday (P < .001), Thursday (P < .001), and Friday (P < .001). There was no significant difference in 90-day readmission risk according to day of surgery. Mean cost was significantly higher for surgeries performed on Wednesday (P < .001), Thursday (P < .001), and Friday (P < .001). When LOS was held constant across every day of the week, the mean cost of TKA decreased by $247 for Wednesday, $627 for Thursday, and $394 for Friday.


Primary TKA performed later in the week is associated with an increased LOS and increased costs of admission, but a similar risk of 90-day readmission. Preferential scheduling of primary TKA cases early in the week, as well as the development of standardized clinical care pathways with appropriate weekend staffing of social work and rehabilitation services, could help to decrease the daily variation in LOS and increase the value of TKA episodes.

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