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Emerg Med J doi:10.1136/emermed-2012-202169
  • Original article

Deriving the East Riding Elbow Rule (ER2): a maximally sensitive decision tool for elbow injury

  1. Will Townend
  1. Emergency Department, Hull Royal Infirmary, Hull, UK
  1. Correspondence to Will Townend, Emergency Department, Hull Royal Infirmary, Hull HU3 2JZ, UK; william.townend{at}hey.nhs.uk
  • Received 13 November 2012
  • Revised 9 January 2013
  • Accepted 17 January 2013
  • Published Online First 8 February 2013

Abstract

Objective To derive a maximally sensitive decision rule for clinical practice to rule out the need for x-ray examination after elbow injury in adults and children.

Methods Emergency department patients with acute elbow injury were recruited. Practitioners used their usual judgement to assess whether x-ray examination was required. Radiographs were reported on by radiologists blind to clinical assessment. Patients not x-rayed were followed-up at 7 days by telephone interview, and those with ongoing pain were recalled for assessment. Recursive partitioning was used to derive a maximally sensitive decision tool. Inter-rater variability for significant discriminators was subsequently evaluated by a cohort of 20 emergency department clinicians.

Results 492 patients were recruited (May 2006–November 2008): 50.4% were male; 26.8% were children; 444 (90.2%) had an x-ray; 167 (37.6%) showed abnormality. A follow-up telephone interview was conducted with 28; none were recalled. Thirteen could not be contacted, none of whom returned within 3 months. Sixteen patients with fractures were able to fully extend their elbow. The sensitivity of elbow extension alone was 84% (95% CI 77% to 88%), with specificity of 54% (95% CI 53% to 58%). A 100% sensitive (95% CI 97% to 100%) decision rule for adults (n=348) was derived based on (1) inability to fully extend the elbow, (2) tenderness over radial head, olecranon or medial epicondyle, and (3) presence of bruising (specificity 24% (95% CI 19% to 30%)). A similar rule for children could not be derived.

Conclusions A simple and highly sensitive clinical decision rule for adult elbow fracture was derived in our cohort. A validation study in a second population is now required. At present, we are unable to recommend a rule-out strategy for elbow injuries in children.