Background: Elbow injuries are common, accounting for 2 to 3 percent of emergency department visits. Unlike those designed for other joint injuries, there is no validated rule to help determine which elbow injuries require radiography. Several small studies have suggested that the ability to fully extend the elbow may rule out clinically significant bony injury and could eliminate or reduce the use of radiography. Appelboam and colleagues studied the elbow extension test in adults and children in routine clinical practice to rule out bony injury.

The Study: Participants were drawn from multiple emergency departments in England. The study design for children was observational, and for adults was a prospective validation trial. With the goal of achieving greater than 99 percent sensitivity, the authors determined that 300 adults (older than 15 years) and 300 children (three to 15 years of age) with negative extension tests and no fractures needed to be enrolled. Patients who presented more than 72 hours after injury and those with multiple injuries, known neuromuscular or bony diseases, or no history of trauma were excluded. The elbow extension test involves the seated participant flexing the shoulders to 90 degrees and then extending and locking both elbows. The injured and uninjured elbows are compared visually; those with equal extension are considered “full extension.”

In the adult trial, those with full extension (i.e., a negative test) did not undergo radiography, and were discharged with pain medication and a sling, as needed. These patients were contacted in seven to 10 days by phone; those with ongoing concerns, including the inability to fully extend the elbow, persistent or worsening pain, and difficulty using the arm, were recalled for radiography. Children had radiography during the initial evaluation at the discretion of the treating physician, regardless of the elbow extension test findings.

Results: Of the 958 adults in the analysis, 313 (33 percent) could extend their elbow fully, and all but two in this group completed follow-up. Five fractures were ultimately diagnosed, with two requiring surgery for olecranon fracture. Of the 647 adults who could not fully extend the elbow, 311 (48 percent) had confirmed fractures and 84 (13 percent) had elbow joint effusions. Of the 778 children included in the analysis, 289 (37 percent) could fully extend their elbow. Twelve fractures and six effusions were diagnosed in this group. Among the 491 children who could not fully extend their elbow, there were 210 fractures (43 percent) and 59 elbow joint effusions (12 percent).

The overall sensitivity of the elbow extension test was 96.8 percent, with a specificity of 48.5 percent. The negative predictive value was 98.4 percent for adults and 95.8 percent for children. Adults with a negative test had a 1.6 percent chance of fracture; children with a negative test had a 4.2 percent risk.

Conclusion: The elbow extension test is a reliable tool to rule out elbow fracture in adults, assuming an olecranon fracture is not suspected. The authors caution against using it as a single diagnostic test in children.