Persistent neuropathic-like pain phenotype after arthroscopic repair of massive rotator cuff tears: occurrence, associated factors, and a preoperative four-domain risk score.

backgroundPersistent neuropathic-like pain may limit recovery after arthroscopic repair of massive rotator cuff tears, but its postoperative occurrence, associated factors, and preoperative risk stratification remain insufficiently characterized. This study estimated the 6-month occurrence proportion, examined associated factors, and developed an internally validated preoperative four-domain risk score.

methodsThis single-center retrospective cohort screened 418 consecutive adults treated between January 2019 and December 2024; 346 met the eligibility requirements, including ascertainable 6-month primary-outcome and 12-month follow-up phenotype data. The primary outcome required persistent or recurrent pain in the operated shoulder and related region at 6 months, a Douleur Neuropathique 4 (DN4) questionnaire score ≥ 4, a painDETECT score ≥ 13, at least 1 documented abnormality on a prespecified bedside sensory examination, and exclusion of a more plausible cause. painDETECT scores of 13-18 provided supportive evidence within the composite definition, for which all criteria were required, whereas scores ≥ 19 defined the strict sensitivity-analysis outcome. The 4 domains prespecified before outcome modeling were the central sensitization-related symptoms-poor sleep composite phenotype (Central Sensitization Inventory [CSI] ≥ 40 and Pittsburgh Sleep Quality Index [PSQI] > 5), preoperative subthreshold neuropathic-like symptoms, a magnetic resonance imaging (MRI)-based degeneration-tension phenotype, and limited socioeconomic and rehabilitation resources. Each domain contributed 1 point. A logistic regression model with the total score as the sole predictor was evaluated using 1,000 bootstrap resamples.

resultsThe phenotype occurred in 46 of 346 patients (13.3%) at 6 months, compared with 16.2% at 3 months and 8.1% at 12 months. Among patients positive at 3 months, 73.2% remained positive at 6 months. All 4 domains were more frequent in outcome-positive patients (all P ≤ 0.001). The observed 6-month occurrence proportions across scores of 0-4 were 4.7%, 5.8%, 14.9%, 35.5%, and 60.0%, respectively (P for trend < 0.001). Each 1-point increase was associated with an odds ratio (OR) of 2.57 (95% confidence interval [CI], 1.96-3.37). The apparent area under the receiver operating characteristic curve (AUC) was 0.785 (95% CI, 0.705-0.864), and the optimism-corrected AUC was 0.784. The corrected calibration intercept and slope were 0.03 and 1.01, respectively, and the corrected Brier score was 0.092. At a threshold of ≥ 3 points, sensitivity was 56.5%, specificity was 90.0%, positive predictive value was 46.4%, and negative predictive value was 93.1%. Included and excluded patients differed little in age, sex, and tear size, whereas excluded patients had higher preoperative pain intensity (P = 0.024; absolute standardized difference [ASD] = 0.30).

conclusionsThe score showed reasonable internal discrimination and calibration and may inform preoperative risk stratification in comparable settings; external validation remains required. The composite outcome represents a clinically identifiable phenotype with potentially neuropathic, nociplastic, or mixed mechanisms, supporting mechanism-oriented assessment for postoperative pain management.