Defining the Minimal Clinically Important Difference of the PainDETECT Questionnaire: Implications for Personalized Pain Management After Total Knee Arthroplasty.

Abstract

The PainDETECT Questionnaire (PDQ) is a validated tool for identifying neuropathic pain (NeP) and assessing postoperative pain. However, its minimal clinically important difference (MCID) remains undefined, particularly in Chinese patients undergoing total knee arthroplasty (TKA). This study aimed to determine the MCID for the PDQ in patients who have NeP and nociceptive pain (NP) after TKA and evaluate its correlation with Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), five-level EuroQoL group's five-dimension questionnaire (EQ-5D-5L), and Central Sensitization Inventory-Chinese Version (CSI-CV). In this prospective cohort study, 625 patients undergoing unilateral TKA were assessed preoperatively and at 1-year postoperatively using PDQ, WOMAC, EQ-5D-5L, and CSI-CV. The MCID for the PDQ was calculated using anchor-based, distribution-based, and receiver operating characteristic curve methods. The MCID was higher in the NeP group than in the NP group. The anchor-based MCID was 5.0 [95% confidence interval, 4.3 to 5.6] in NeP and 3.0 [95% confidence interval, 2.9 to 3.2] in NP, while the distribution-based method yielded 4.4 and 2.6, respectively. The receiver operating characteristic cutoff identified MCID thresholds of 4.0 points in NeP (area under the curve, 0.98; P < 0.001) and 2.5 points in NP (area under the curve, 0.94; P < 0.001). In NeP, PDQ changes correlated strongly with WOMAC (r = 0.75), EQ-5D-5L (r = 0.67), and CSI-CV (r = 0.74) (P < 0.05). In NP, correlations were moderate for WOMAC (r = 0.45), EQ-5D-5L (r = 0.56), and CSI-CV (r = 0.24) (P < 0.05). The MCID for the PDQ score of patients who had Nep after TKA was greater than that for patients who did not have Nep. This study provides evidence-based MCID values for the PDQ in Chinese TKA patients, supporting its use in personalized preoperative and postoperative pain management.