Ultrasound-Guided vs Landmark-Based Hematoma Block for Distal Radius Fractures in the Emergency Department

Hematoma block (HB) is a common analgesic technique for distal radius fracture (DRF) reduction in the ED. Whether ultrasound guidance (USG) improves analgesic efficacy compared with traditional landmark-based (LMB) HB is uncertain. The study objective was to compare pain outcomes between USG and LMB HB techniques.

This was a prospective, randomized, controlled trial of adult patients presenting with DRF requiring closed reduction to a single academic ED. Subjects were randomized to USG or LMB HB. Pain was assessed via a 0–10 visual analog scale (VAS) at four times: pre-HB (t0), post-HB/pre-reduction (t1), intra-reduction (t2), at discharge (t3). VAS distributions were evaluated for normality using a Shapiro–Wilk test. Absolute VAS scores were compared between groups via non-parametric methods (Kruskal–Wallis) and Hodges–Lehmann estimation of median differences and 95% confidence intervals (CIs). Interval changes in VAS scores were analyzed using two-sample t tests when normally distributed. Clinically significant pain (CSP) change was defined as a priori VAS change of ≥1.3 points and analyzed as a dichotomous outcome using risk ratios (RRs) and absolute risk differences (ARDs) with 95%CIs. Secondary outcomes included analgesic efficacy, patient satisfaction, needle placement satisfaction. Statistical significance was defined as p<0.05.

Forty patients were enrolled (21 LMB, 19 USG). Baseline characteristics, including pre-block pain scores, were similar between groups. Both HB types resulted in CSP reduction t0→t1; mean VAS decrease was 3.68 (LMB, 95% CI 2.24–5.12) and 2.98 (USG, 95% CI 1.77–4.19). Pain increased t1→t2 in both groups [mean VAS −2.83 LMB (95% CI −4.14 to −1.51) and −2.27 USG (95% CI−3.53 to−1.02)]. There was no statistically significant difference between USG and LMB blocks for absolute VAS scores at t1, t2, or t3 or any between-group differences for interval changes in VAS scores. CSP improvement from pre- to post-HB occurred in 81% of LMB and 79% of USG HB (RR 0.98, 95% CI 0.71–1.33). Rates of CSP improvement at t3 were also comparable. No differences were observed in any secondary outcomes.

HB provides rapid and CSP reduction for DRF reduction. In our small sample, USG did not confer superior pain relief, pain trajectory, or patient satisfaction compared with LMB HB. Single center, small sample size, and unblinded operators limits generalizability.