DN4-Positive Neuropathic Pain Features in End-Stage Knee Osteoarthritis Awaiting Arthroplasty: Prevalence and Relationship With Function and Quality-of-Life.

Abstract

Objectives: This cross-sectional study investigated the occurrence of neuropathic pain features (NP) in individuals with end-stage knee osteoarthritis (KOA) referred to total knee arthroplasty (TKA) and explored its association with functional and quality-of-life outcomes.

Methods: In 902 patients, NP was screened using the Douleur Neuropathique 4 (scores ≥ 4). Distribution of NP features (positive/negative) regarding sex were assessed with z-test for proportions. The influence of NP features on the outcomes (visual analog scale for pain, WOMAC, SF-36) were tested with the Mann-Whitney U, followed by a multivariate logistic regression model to identify independent predictors of NP features, using 5% as statistical threshold.

Results: The cohort was 72.6% female, with a mean ± SD age of 70 ± 8 years. NP-positive features prevalence was 28.6% (95% CI of 25.7%-31.6%), which was significantly higher in females (31.5%) than males (21.1%; p < 0.001). Patients with NP-positive features reported worse scores across all measured domains: higher pain intensity (VAS; p < 0.001), worse knee-related symptoms/function (WOMAC pain, function, and total scores; all p < 0.001), and lower quality-of-life in specific SF-36 domains (general health, vitality, role-emotional, mental health; all p < 0.01). The multivariate model confirmed that higher WOMAC total score and specific SF-36 scores were independently associated with NP-positive features.

Conclusions: NP features are prevalent in approximately one-third of the patients with end-stage KOA awaiting arthroplasty, particularly among females. Its presence is independently associated with poorer joint-related function and reduced quality-of-life, suggesting the potential value of NP features assessment and management into pre- and postsurgical care.