Femoral nerve blockade administered preclinically for pain relief in severe knee trauma is more feasible and effective than intravenous metamizole: a randomized controlled trial.

Background: Before clinical treatment and during transportation, the analgesic therapy offered to patients with painful knee trauma may be quite insufficient. We hypothesize that a femoral nerve blockade for analgesia can be administered in a preclinical setting at the injury site and provides better pain relief than intravenous metamizole, whose analgesic effect is comparable with that of opioids. Methods: After an initial clinical investigation, 52 patients were randomized according to computer-generated codes; 26 patients received a femoral nerve blockade and 26 received metamizole. The treatment was started at the injury site and the level of pain on the 100-mm visual analog scale was assessed at the beginning and the end of treatment. Results: Pain and anxiety scores were significantly reduced by half in the femoral nerve blockade group; peripheral vasoconstriction was noted in 26 patients at the injury site and dropped to six at the time of arrival at the hospital. Two of 26 patients in the blockade group did not benefit from the treatment. In the metamizole group, pain and anxiety did not decrease significantly; vasoconstriction persisted in all patients. Conclusion: Patients with painful knee trauma benefited from femoral nerve blockade administered before hospitalization. The treatment can be administered safely in the preclinical setting and provides effective analgesia.