Risk Factors for Delayed Inpatient Functional Recovery after Total Knee Arthroplasty

PURPOSE To determine the predictive value of surgery-related variables for delayed inpatient functional recovery (i.e., ≥3 days to reach functional independence) after TKA. METHOD 193 consecutive people undergoing TKA were included in this prospective cohort study. Inpatient functional recovery was measured daily using the Iowa Level of Assistance scale (ILAS). Two persons reviewed medical records to extract patient characteristics (i.e., age, sex, and BMI) and surgical factors (i.e., blood loss, tourniquet time, postoperative morphine use, and surgical experience). Odds ratios (OR) and area under the curves (AUC) were calculated to determine the predictive value of the putative factors and of the model on delayed functional recovery, respectively. RESULTS Delayed functional recovery was apparent in 76 (39%) people. Higher age, female sex, and higher BMI were all independent risk factors for delayed functional recovery (AUC (95%-CI); 0.72 (0.65-0.80)), whereas blood loss (OR (95%-CI); 1.00 (0.99-1.01)), tourniquet time (OR = 1.00 (0.98-1.02)), and postoperative morphine use (OR = 0.88 (0.37-2.06)) did not statistically improve the predictive value of the model, while surgical experience did (OR = 0.31 (0.16-0.64); AUC = 0.76 (0.69-83)). CONCLUSIONS Surgery-related factors contribute little to the patient-related characteristics in a predictive model explaining delayed functional recovery after TKA in daily orthopaedic practice.