How Back Pain Affects Patient Satisfaction After Primary Total Knee Arthroplasty

Although back pain (BP) has been shown to be a predictor of dissatisfaction after total knee arthroplasty (TKA) in some reports, these studies did not use a scale to quantify the degree of pain. The purpose of this study was to quantify the effect of BP intensity on patient satisfaction reported at 1 year after TKA. A multicenter prospective cohort was taken in which 9,057 patients undergoing primary unilateral TKA were enrolled in FORCE-TJR and demographic and clinical data were collected. Back pain (BP) intensity was assessed using the Oswestry back disability index (ODI) pain intensity questionnaire. Patients were classified into 4 categories based on the severity of BP. Patient-reported outcomes (PROs) were collected preoperatively and postoperatively after 1 year including the Knee injury and Osteoarthritis Outcome Score (KOOS) (total score, pain, Activities of Daily Living (ADL), and Quality of Life (QOL), Short-Form health survey 36-item (SF-36) Physical Component Score (PCS), and Mental Component Score (MCS)). We used a validated 5-point Likert satisfaction scale. Univariate analyses of the difference between the satisfied and dissatisfied patients’ groups was performed. Multivariate logistic regression models with 95% confidence interval (CI) were used to quantify the effect of BP intensity on patient dissatisfaction at 1 year. Receiver operating characteristic (ROC) analyses were performed with measurement of area under curve (AUC). At 1 year, a total of 1,657 TKA patients (18.3%) were dissatisfied. A total of 4,765 patients (52.6%) reported back pain at the time of surgery, including mild BP in 2,264 patients (24.9%), moderate BP in 1,844 patients (20.3%), and severe BP in 657 patients (7.2%). Severe back pain was significantly associated with patient dissatisfaction at 1 year after TKA (P = .0006). The multivariate regressions showed that patients who had severe BP were 1.6 times more likely to be dissatisfied when compared to patients who had no BP [odds ratio (OR) 1.63; 95% confidence interval (CI) (1.23-2.16), P = .0006]. While patients who had mild BP [OR 0.98; 95% CI (0.82-1.17), P = .87] or moderate BP [OR 0.97; 95% CI (0.80-1.18), P = .78] were not associated with an increased likelihood of dissatisfaction. Other predictive variables for dissatisfaction, include age [OR for younger patients