Pre-operative EQ-5D-5L is a strong predictor of meaningful improvement in quality of life following primary total knee arthroplasty

IntroductionPredicting which patients will get meaningful benefit from total knee arthroplasty remains a challenge. Our aim was to assess if pre-operative quality of life (EuroQol 5-Dimension, 5-Level instrument; EQ-5D-5L) can predict the likelihood of a patient achieving post-operative improvement in patient-reported outcome measures (PROMS) following total knee arthroplasty to a level of minimum clinically-important difference (MCID).Materials and methodsThis was a retrospective analysis of a prospective cohort of total knee arthroplasty patients. EQ-5D-5L and Oxford Knee Scores (OKS) were recorded pre-operatively, 6 months and 2 years post-operatively. The primary outcome measure was achievement of MCID in EQ-5D-5L at 2 years. Multivariable analysis through multiple logistic regression was performed to assess for independent predictors of MCID in EQ-5D-5L, OKS and re-operation at 2 years.Results400 patients were included, with 57% female and a mean age of 66 years. Pre-operative EQ-5D-5L was the only strong predictor of post-operative EQ-5D-5L MCID (OR: 0.016, CI: 0.004 to 0.06), when adjusted for age, gender, BMI, ASA, smoking status and surgeon grade. The optimal pre-operative EQ-5D-5L threshold was found to be 0.53 by Youden's index, with a sensitivity of 70% and specificity of 73%.ConclusionsPre-operative quality of life as measured by EQ-5D-5L is a strong independent predictor of reaching MCID in EQ-5D-5L following total knee arthroplasty. Those with worse EQ-5D-5L are more likely to gain meaningful benefit from knee arthroplasty.