Predictive model for postoperative hyperalgesia in patients with lower limb fractures undergoing nerve block surgery

Abstract

Objective: To establish and validate a predictive model for postoperative hyperalgesia in patients with lower limb fractures undergoing nerve block surgery.

Methodology: This retrospective study analyzed 168 patients receiving postoperative nerve block analgesia at Huzhou Nanxun Hospital of Traditional Chinese Medicine (January 2022-October 2024). Patients were stratified into hyperalgesia and non-hyperalgesia groups. Logistic regression identified independent risk factors, followed by nomogram model development and validation using R software.

Results: Hyperalgesia incidence was 14.88% (25/168). Significant differences existed in smoking history, diabetes history, operation time, distal compression at injection site, and ropivacaine dosage (P<0.05). Multivariate analysis confirmed diabetes history (OR=4.12), operation time (OR=3.85), distal compression (OR=0.24), and ropivacaine dosage (OR=3.21) as independent predictors (P<0.05). The nomogram achieved an AUC of 0.819 (95% CI: 0.732-0.906), with calibration curve slope=1 and intercept<0.001. Decision curve analysis showed optimal net benefit at threshold probabilities of 0.05-0.55.

Conclusion: Postoperative hyperalgesia is primarily associated with diabetes history, prolonged operation time, absence of distal compression, and higher ropivacaine dosage. The validated nomogram provides accurate individualized risk prediction.