Association between weekday of surgery and length of hospital stay among patients undergoing primary total knee arthroplasty in Singapore: a secondary analysis based on a retrospective cohort study.

BACKGROUND

Total knee arthroplasty (TKA) demand is increasing globally, necessitating the optimization of hospital length of stay (LOS) to increase efficiency. While weekday scheduling has been linked to LOS variations in Western populations, its impact on Asian healthcare systems remains understudied.

OBJECTIVE

To investigate the associations between operative weekday length and LOS among Singaporean TKA patients, including nonlinear trends and subgroup differences.

METHODS

This retrospective cohort study analyzed 2,394 primary unilateral TKA procedures performed at a Singaporean tertiary hospital (2013-2014). After exclusions (revisions, bilateral cases), 2,333 patients were included. Multivariable linear regression was used to assess LOS associations with surgical weekday (reference: Friday), adjusting for demographics, comorbidities, and procedural factors. Nonlinear relationships were evaluated via restricted cubic splines and piecewise regression. Subgroup analyses explored interactions by sex, anesthesia type, and diabetes status.

RESULTS

Thursday (β = -1.26 days, 95% CI: -1.82 to -0.70, p <  0.001) and Saturday (β = - 1.16 days, 95% CI: - 2.03 to - 0.29, p =  0.009) surgeries resulted in the shortest LOS. Nonlinear analysis revealed a U-shaped curve, with the LOS decreasing from Monday to Thursday (nadir at 3.726 weekdays) and increasing thereafter. Significant interactions emerged for anesthesia type (general vs. regional, p =  0.035), with general anesthesia amplifying LOS reductions.

CONCLUSION

Midweek TKA scheduling, particularly on Thursday, optimizes postoperative efficiency in Singapore's healthcare system. The nonlinear temporal patterns and subgroup-specific effects underscore the importance of institutional resource alignment and personalized scheduling. These findings advocate the integration of weekday-based protocols into fast-track arthroplasty programs, especially for patients undergoing general anesthesia.