Partial evacuation of the fracture haematoma does not potentiate the analgesic effect of infiltrated local anaesthetic in the manipulation of distal radius fractures

Wrist haematoma blocks increase the volume of the fracture-soft tissue envelope and the resulting compartment pressures. We hypothesised that evacuating the haematoma before infiltrating with local anaesthetic would reduce the risk of undue swelling and produce a more effective block as measured by changes in a visual analogue score for pain. A total of 100 patients (100 fractures) were recruited; 77 had the haematoma partially evacuated (Group 1) and 23 did not (Group 2). The volumes of infiltrated anaesthetic, timing of manipulation, rates of re-manipulation and splitting of cast were not different between the two groups. The mean visual analogue score before manipulation in the two groups were 7.8 and 7.5, respectively, which declined to 3.2 and 2.5 at 5 min and to 2.8 and 2.4 at 10 min. The differences in change in visual analogue score were not significant at 5 and 10 min (p = 0.42, p = 0.55). This suggests that evacuation of the haematoma does not influence the analgesic effect of the infiltrated agent.