Association of perineural hydromorphone added to ropivacaine with early analgesic outcomes in proximal humerus fracture surgery: a retrospective cohort study

BACKGROUND: The analgesic benefit of adding perineural hydromorphone (HYD) to ropivacaine (ROP) for proximal humerus fracture surgery remains unclear. OBJECTIVE: The aim of this study is to examine whether adding perineural hydromorphone to ropivacaine was associated with early analgesic outcomes and short-term adverse events. METHODS: This single-center retrospective cohort included 130 consecutive eligible adults (ROP, n = 68; ROP + HYD, n = 62). The primary outcome was 12-h analgesia success, defined as resting visual analog scale (VAS) ≤3. We used multivariable logistic regression and propensity score analyses to account for measured treatment-preceding differences. Sensitivity analyses considered the combined block techniques, intraoperative medications, and postoperative analgesic co-interventions. A 1-point difference on the 0-10 VAS was used to interpret clinical importance. RESULTS: Analgesia success at 12 h occurred in 39/62 patients (62.9%) in the ROP + HYD group and 26/68 (38.2%) in the ROP group [absolute difference 24.7 percentage points, 95% confidence interval (CI) 7.5-39.9; unadjusted odds ratio (OR) 2.74, 95% CI 1.35-5.57; number needed to treat 4.1]. The adjusted OR was 3.72 (95% CI 1.66-8.77), and propensity score analyses gave similar estimates. A sensitivity model that also accounted for superficial cervical plexus and T2 paravertebral field supplementation gave an OR of 3.83 (95% CI 1.67-9.31). Mean VAS differences favored ROP + HYD at 6 h (-0.33, 95% CI -0.65 to -0.02) and 12 h (-0.58, 95% CI -0.86 to -0.29), but both were smaller than 1 point; no difference was detected at 24 h. Median total 24-h rescue opioid consumption was 4.8 morphine milligram equivalents (MME) with ROP + HYD and 6.4 MME with ROP (p = 0.044). An unadjusted exploratory comparison found lower 6-h cortisol with ROP + HYD, but interpretation is limited by heterogeneous routine assay methods and multiple secondary comparisons. No between-group differences in the recorded short-term adverse events were detected. CONCLUSIONS: Adding perineural hydromorphone was associated with a higher proportion of patients achieving resting VAS ≤3 at 12 h. The average VAS differences were modest and no difference was detected at 24 h. Because treatment was not randomized, these findings should be confirmed in a prospective trial.