Persistent postoperative pain at 1 year after orthopedic surgery and its association with functional disability

Orthopedic hip, knee, and spinal surgeries have a relatively high incidence of persistent postoperative pain, with the highest risk observed in Asian ethnicity. This study aimed to investigate the distribution of persistent pain at 1 year after surgery and its associated factors and effects on functional disability.

This secondary analysis of a prospective observational study included 297 patients aged ≥ 55 years who underwent elective total hip arthroplasty, total knee arthroplasty, and spine and spinal cord surgeries under general anesthesia. Data were collected perioperatively and at 3 months and 1 year postoperatively to assess persistent postoperative pain on a numerical rating scale.

At 1 year postoperatively, 34.6% (103/297) of patients reported pain, with a score of ≥ 1 and a mean score of 1.2. Multivariable negative binomial regression analysis revealed that less preoperative bodily pain (risk ratio [RR], 0.97; 95% confidence interval [CI] 0.94-0.99), preoperative C-reactive protein (CRP) level (RR, 1.19; 95% CI 1.01-1.39), and spine and spinal cord surgeries (RR, 2.48; 95% CI 1.30-4.75) increased the risk of persistent pain at 1 year after surgery, which was a significant factor for predicting the 12-item World Health Organization Disability Assessment Schedule 2.0 score (p < 0.001).

The mean score for persistent pain at 1 year after surgery on the numerical rating scale was 1.2. Worse preoperative bodily pain, higher preoperative serum CRP level, and spine and spinal cord surgeries increased the persistent pain score at 1 year after surgery, which was associated with functional disability CLINICAL TRIAL REGISTRATION: This prospective observational study was registered on the University Hospital Medical Information Network (31 December 2015; UMIN000021671).