Can Preoperative Patient-reported Outcome Measures Be Used to Predict Meaningful Improvement in Function After TKA?

Abstract

Background Despite the overall effectiveness of total knee arthroplasty (TKA), a subset of patients do not experience expected improvements in pain, physical function, and quality of life as documented by patient-reported outcome measures (PROMs), which assess a patient's physical and emotional health and pain. It is therefore important to develop preoperative tools capable of identifying patients unlikely to improve by a clinically important margin after surgery.Questions/purposes The purpose of this study was to determine if an association exists between preoperative PROM scores and patients' likelihood of experiencing a clinically meaningful change in function 1 year after TKA. Methods A retrospective study design was used to evaluate preoperative and 1-year postoperative Knee injury and Osteoarthritis Outcome Score (KOOS) and SF-12 version 2 (SF12v2) scores from 562 patients who underwent primary unilateral TKA. This cohort represented 75% of the 750 patients who underwent surgery during that time period; a total of 188 others (25%) either did not complete PROM scores at the designated times or were lost to follow-up. Minimum clinically important differences (MCIDs) were calculated for each PROM using a distribution-based method and were used to define meaningful clinical improvement. MCID values for KOOS and SF12v2 physical component summary (PCS) scores were calculated to be 10 and 5, respectively. A receiver operating characteristic analysis was used to determine threshold values for preoperative KOOS and SF12v2 PCS scores and their respective predictive abilities. Threshold values defined the point after which the likelihood of clinically meaningful improvement began to diminish. Multivariate regression was used to control for the effect of preoperative mental and emotional health, patient attributes quantified by SF12v2 mental component summary (MCS) scores, on

Do Aggregate Socioeconomic Status Factors Predict Outcomes for Total Knee Arthroplasty in a Rural Population?

“…26,38 Along with our results, other studies have noted that despite TKA’s cost-effectiveness, 1,2 many patients may not achieve significant improvement in physical function as measured by PRO change score. 15,39 In our work, 37% of surgeries did not result in clinically significant improvement in physical function. Future research should explore whether patient satisfaction has any relationship with their reported physical function improvement.…”

“…19 Our AUC model values of 0.81 and 0.80 improve on another medical center’s model for PCS improvement of 5 points at 1 year, which had a multivariate predictive AUC value of 0.71 with fewer variables. 15 That model included SF-12 PCS and MCS, gender, age, and race. In a sub-analysis, we matched their variables to our data with only 1-year PCS follow-up measures and achieved an AUC of 0.77 (95% CI 0.73–0.81) (data not shown).…”

“…15,30 We used dichotomous outcomes to enable satisfactory predictive models. The change score was measured as the latest postoperative recorded PCS subtracted by the latest preoperative score.…”

“…Several preoperative factors have been noted to be associated with TKA outcomes, including gender, 9–12 age, 9–13 physical function, 9,12–14 mental function, 15 body mass index, 12,16 and medical comorbidities. 12,17 Little is known about how various demographic and socioeconomic status (SES) variables are associated with TKA outcomes after adjustment for other factors, although they are studied regularly across other medical disciplines.…”

“…We elected to only use preoperative variables that may be self-reported by the patient outside of a medical setting; other papers have noted the ability to create strong predictive models using only these types of variables. 15,23 We hypothesized that SES variables would predict each outcome in an adjusted multivariate model, and that the addition of SES variables would significantly improve each predictive model.…”