Influence of pre-operative variables on length of stay and outcome after unicompartmental knee replacement

Abstract

The objective of this study was to determine whether pre-operative characteristics correlate with length of hospital stay or postoperative outcomes at 1 year following medial unicompartmental knee replacements (UKR). One hundred and eighty nine UKR patients and 223 knees were assessed pre-operatively and at one year post-operatively. The pre-operative variables of interest included: gender, age, body mass index (BMI), smoking history, uni- or bilateral procedures, pre-operative location, operative location, pre-operative Oxford Knee Score (OKS), clinical and functional American Knee Society Score (AKS) or Short Form-12 (SF-12). One year outcomes included the OKS, the clinical and functional AKS, SF-12, knee range of motion, and maximum and minimum visual analogue scale (VAS) pain scores, and length of hospital stay. Findings suggested that most pre-operative variables assessed correlated to maximum pain outcomes, and that the pre-operative clinical and functional AKS and SF-12 scores correlated with 1 year OKS and clinical AKS. Length of stay correlated with pre-operative OKS, SF-12, functional AKS, age and whether patients underwent uni- or bilateral procedures. Further study is recommended to compare these findings with alternative UKR populations.