Postoperative joint pain is associated with long-term all-cause mortality after total joint arthroplasty

The aims of this study were to assess (1) if postoperative joint pain can predict long-term all-cause mortality after total joint arthroplasty (TJA), and (2) if postoperative joint pain was associated with causes of death (COD) in TJA patients. Patients who underwent total knee or hip arthroplasty were assessed once for their postoperative joint pain at least one-year after TJA using the Western Ontario and McMaster Universities Osteoarthritis Index Likert 3.0 pain subscale. Three pain definitions were utilized: "sustained pain" - pain on all five questions, "pain while active" - pain while walking and taking stairs, and "pain at rest" - pain while sitting/lying and at night while in bed. Patients reporting no pain were classified as controls. Associations between postoperative joint pain and mortality were assessed using Kaplan-Meier survival analysis and multivariable Cox proportional hazards regression to adjust for age at TJA, sex, body mass index (BMI), cardiovascular diseases (CVD), and cancer. The distribution of COD between pain groups and controls were compared using Fisher's exact test. A total of 727 patients were included in the study, of which 129 (18%) were deceased. The prevalence of postoperative sustained pain, pain while active, and pain at rest at 4-year after TJA was 10, 17, and 12%, respectively. The all-cause mortality rate at 11-year after TJA was 20, 26, 19, and 15% in these pain groups and controls, respectively, significantly higher in pain while active group (p = 0.006). Pain while active was positively associated with mortality when knee and hip patients were analyzed together and separately (p ≤ 0.03, hazard ratio (HR)≥1.80), and the significances became stronger after adjusting for age at surgery, sex, BMI, CVD, and cancer (p < 0.001, HR ≥ 2.57). No association was observed between postoperative joint pain and COD. Our results demonstrated that postoperative joint pain could be an important predictor for long-term all-cause mortality in TJA patients.