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

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

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 the development and validation of a nomogram model using R.

Hyperalgesia incidence was 14.88% (25/168). Significant differences existed in smoking history, diabetes history, operation time, distal compression at the injection site at injection site, and ropivacaine dosage (P<0.05). Multivariate analysis confirmed diabetes history (OR=4.12), operation time (OR=3.85), distal compression at the injection site (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 a calibration curve slope of 1 and an intercept <0.001. Decision curve analysis showed optimal net benefit at threshold probabilities between 0.05 and 0.55.

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