OBJECTIVE

To investigate whether neuropathic-like pain, identified using the PainDETECT questionnaire, predicts postoperative symptoms, using data from 2 independent, prospective cohort studies.

PATIENTS AND METHODS

Data were collected from patients undergoing primary knee arthroplasty for primary osteoarthritis recruited to the Evaluation of perioperative Pain in Osteoarthritis of the kNEe (EPIONE) Study n=120, from October 1, 2011, to May 30, 2014, and the Clinical Outcomes in Arthroplasty Study (COASt) n=404, from January 1, 2010, to December 31, 2018). The PainDETECT questionnaire score was used to divide patients into nociceptive (<13), unclear (13-18), and neuropathic pain (>18) groups preoperatively using validated cutoffs. As the neuropathic group also captures nociplastic pain, we used neuropathic-like to represent this combination. Surgical outcome was compared between groups using the Oxford Knee Score (OKS) and the presence of moderate to severe pain 12 months after arthroplasty.

RESULTS

Total of 296 (56%) reported nociceptive, 144 (27%) unclear, and 84 (16%) neuropathic-like pain preoperatively. Patients in the neuropathic-like pain group had significantly worse OKS postoperatively, compared with the nociceptive group (34 [12] vs 40 [8], <.05), independent of baseline OKS, age, sex, and body mass index. Moderate to severe pain 12 months after arthroplasty was statistically significantly higher in the unclear (OR 2.19 [95% CI, 1.36-3.53]) and neuropathic-like (OR, 2.83 [95% CI, 1.58-5.09]) pain groups when compared with the nociceptive group.

CONCLUSION

Patients classified presurgery as having unclear and neuropathic pain by the modified PainDETECT have considerably worse outcomes after surgery. Neuropathic pain categorized by this tool commonly has centralized pain features and is a potential predictor of ongoing postsurgical pain. Knowledge of this may aid informed decision-making with respect to surgical intervention for those with knee osteoarthritis.