Multi- and univariate analyses of the weekend effect for elective lower-limb joint replacements.

Introduction The weekend effect is a perceived difference in outcome between medical care provided at the weekend when compared to that of a weekday. Clearly multifactorial, this effect remains incompletely understood and variable in different clinical contexts. In this study we analyse factors relevant to the weekend effect in elective lower-limb joint replacement at a large NHS multispecialty academic healthcare centre. Materials and Methods We reviewed the electronic medical records of 352 consecutive patients who received an elective primary hip or knee arthroplasty. Patient, clinical and time-related variables were extracted from the records. The data were anonymised, then processed using a combination of uni- and multivariate statistics. Results There is a significant association between the selected weekend effect outcome measure (postoperative length of stay) and patient age, American Society of Anesthesiologists classification, time to first postoperative physiotherapy and time to postoperative radiography but not day of the week of operation. Discussion We were not able to demonstrate a weekend effect in elective lower-limb joint replacement at our institution nor identify a factor that would require additional weekend clinical medical staffing. Rather, resource priorities would seem to include measures to optimise at-risk patients preoperatively and measures to reduce time to physiotherapy and radiography postoperatively. Conclusions Our findings imply that postoperative length of stay could be minimised by strategies relating to patient selection and access to postoperative services. We have also identified a powerful statistical methodology that could be applied to other service evaluations in different clinical contexts.