Elbow extension test to rule out elbow fracture: multicentre, prospective validation and observational study of diagnostic accuracy in adults and children

OBJECTIVE To determine whether full elbow extension as assessed by the elbow extension test can be used in routine clinical practice to rule out bony injury in patients presenting with elbow injury. DESIGN Adults: multicentre prospective interventional validation study in secondary care. Children: multicentre prospective observational study in secondary care. SETTING Five emergency departments in southwest England. PARTICIPANTS 2127 adults and children presenting to the emergency department with acute elbow injury. INTERVENTION Elbow extension test during routine care by clinical staff to determine the need for radiography in adults and to guide follow-up in children. MAIN OUTCOME MEASURES Presence of elbow fracture on radiograph, or recovery with no indication for further review at 7-10 days. RESULTS Of 1740 eligible participants, 602 patients were able to fully extend their elbow; 17 of these patients had a fracture. Two adult patients with olecranon fractures needed a change in treatment. In the 1138 patients without full elbow extension, 521 fractures were identified. Overall, the test had sensitivity and specificity (95% confidence interval) for detecting elbow fracture of 96.8% (95.0 to 98.2) and 48.5% (45.6 to 51.4). Full elbow extension had a negative predictive value for fracture of 98.4% (96.3 to 99.5) in adults and 95.8% (92.6 to 97.8) in children. Negative likelihood ratios were 0.03 (0.01 to 0.08) in adults and 0.11 (0.06 to 0.19) in children. CONCLUSION The elbow extension test can be used in routine practice to inform clinical decision making. Patients who cannot fully extend their elbow after injury should be referred for radiography, as they have a nearly 50% chance of fracture. For those able to fully extend their elbow, radiography can be deferred if the practitioner is confident that an olecranon fracture is not present. Patients who do not undergo radiography should return if symptoms have not resolved within 7-10 days.