Abstract
With the increasing demand for hip and knee replacement, and the increasing pressure to move towards routine seven-day services within the National Health Service, the trend towards weekend operating is set to increase. We aimed to determine whether planned, elective total hip and total knee replacement performed at the weekend is associated with a different 30-day mortality versus those performed between Monday and Friday.
We used National Joint Registry of England, Wales, Northern Ireland and Isle of Man (NJR) linked to Office for National Statistics (ONS) data. The study dataset comprised 118,096 joint replacement episodes performed at the weekend and 1,233,882 episodes done on a weekday. The main outcome measure was 30-day all-causes mortality. We applied a survivorship analysis using a Kaplan-Meier framework to examine the 30-day cumulative mortality rate for all elective hip and knee replacements performed in England and Wales between 1st April 2003 and 31st December 2014, with Cox proportional-hazards regression models to assess for time-dependent variation and adjust for identified risk factors for mortality.
For hip replacement the cumulative 30-day mortality was 0.15% (95%CI: 0.12–0.19) for patients operated on at the weekend versus 0.20% (0.19–0.21) for patients undergoing surgery during the normal working week. For knee replacement the cumulative 30-day mortality was 0.14% (0.11–0.17) for patients operated on at the weekend versus 0.18% (0.17–0.19) for patients undergoing surgery during the normal working week. The lower mortality associated with weekend operating was most apparent in the later years of the audit (2009 to 2014) and remained after adjustment for any differences in patient age, gender, American Society of Anaesthesiologist grade, surgeon seniority, surgical and anaesthetic practices, and thrombo-prophylaxis choice in weekend versus weekday operated patients.
Hip and knee replacements are routinely performed on Saturdays, and to a lesser extent on Sundays, in England and Wales and are not associated with an increased risk of post-operative mortality.
