Stratified Recovery Curves for Patient-Reported Outcomes After Primary Total Knee Arthroplasty

Background: There remains a lack of literature on how patient demographics and modifiable factors influence patient-reported outcome recovery curves following primary total knee arthroplasty (TKA). This study assessed how these factors influence the progression of patient-reported outcomes following primary TKA and to create visual aids to assist in perioperative counseling. Methods: Prospective multicenter data from 2196 patients who underwent primary TKA were analyzed using generalized estimating equations to model longitudinal Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) scores collected preoperatively and at 1, 3, 6, and 12 months postoperatively. Models were adjusted for repeated measures within patients and included interaction terms between time and demographic or modifiable risk factors to assess differences in recovery trajectories. Stratifications included age, sex, race, ethnicity, body mass index, smoking status, preoperative opioid use, and preoperative activity level. Clinical significance was defined using a minimal clinically important difference of 6.25 points. Results: Patients who were less than 50 years old, women, black, Hispanic, underweight, or consumed opioids preoperatively all demonstrated significantly lower KOOS JR scores throughout the postoperative recovery curve. However, the rate at which women recovered was significantly greater at each postoperative time point. Black patients recovered at a similar rate compared to white patients, which was also the case for Hispanic vs non-Hispanic patients. While patients who used opioids preoperatively had lower overall KOOS JR scores, they demonstrated significantly quicker recoveries for the first 3 months postoperatively, but these differences became insignificant thereafter. Conclusions: Several patient demographics and modifiable risk factors impact patient's recovery following primary TKA, which can assist in counseling patients regarding recovery following primary TKA.