Elb-‘ow’! Does my patient with an elbow injury require an x-ray?
Resident Clinical Pearl (RCP) – December 2017
Allyson Cornelis R1 FMEM, Dalhousie University, Saint John, New Brunswick
Reviewed by Dr. David Lewis
Why should you care?
Trauma to the upper extremity can result in injury to the various components of the elbow joint and associated anatomical structures. Important neurovascular structures associated with the elbow joint are the brachial artery, radial artery, ulnar artery, median, radial, and ulnar nerve¹. Elbow injuries causing fracture increase the likelihood of neurovascular damage. If fractures are missed, this may result in further damage and complications including prolonged functional limitations to the joint, nerve damage causing distal functional decline, and potential vascular compromise to the limb more distal to the injury.
Tintinalli’s Comprehensive Guide to Emergency Medicine.2
Functionally, the elbow has two primary movements: flexion/extension, and supination/pronation¹.
Fractures at the elbow may occur at the distal humerus (supracondylar, epicondylar, condylar, trochlea, and capitellum fractures), the proximal ulna (coronoid process, olecranon fractures), and the proximal radius (radial head fractures)¹. Of these, radial head fractures are the most common. Common mechanisms for these injuries include falling on an outstretched hand and direct blows to the elbow.
How do I know if my patient requires an X-ray for their elbow pain?
There is a rule for that! The elbow extension rule!
Simply stated: If a patient with an elbow injury is able to fully extend their elbow, they are unlikely to have a fracture and do not require imaging³.
The “how to”:
- Provide analgesia to patients
- Have patient seated with supinated arms
- Have patient flex shoulder to 90 degrees
- Ask patient to fully extend elbow to either the point of locking or the same level of extension as contralateral side
Of course, no rule is perfect, and the patient should be reassessed later if the following occur
- Can no longer fully straighten elbow
- Pain is getting worse
- Cannot use their arm as previous
The patient should have imaging at the current visit if:
- Patient is unreliable for follow up
- If olecranon fracture is possible
The evidence³
Of 1740 patients presenting within 72 hours of traumatic elbow injury, 31% had a fracture³. In adults with the ability to fully extend their elbow following trauma, there was a 2% chance they had a fracture. In adults unable to fully extend their elbow following trauma, there was a 48% chance they had a fracture.
In children able to fully extend their elbow following trauma, there was a 4% chance they have a fracture, and in children unable to fully extend their elbow following trauma, there was a 43% chance they had a fracture³.
Bottom Line: Patients presenting with elbow trauma and an inability to extend their elbow fully require radiography. Those able to fully extend their elbow do not require imaging unless follow up is unreliable, an olecranon fracture is suspected. Caution should be exercised with assessment in children.
Addendum:
Consider adding PoCUS to your clinical assessment of elbow injuries. Elbow joint effusions are very easily visualized. The presence of a joint effusion in a patient with elbow pain following trauma is a significant finding and warrants further investigation with radiography. Some studies have shown PoCUS to be more sensitive than x-ray in diagnosing occult elbow fractures.
References
(1) Appleboam, A., Reuben, AD., Benger, JR., Beech, F., Dutson, J., Haig, S., Lloyd, G. (2008). Elbow extension test to rule out elbow fracture: Multicentre, prospective validation and observational study of diagnostic accuracy in adults and children. British Medical Journal, 337:a2428.
(2) Tintinalli, JE. (2016). Cardiogenic Shock (8th ed.) Tintinalli’s Emergency Medicine: A Comprehensive Study Guide (pages 1816-1817). New York: McGraw-Hill.
(3) Sheehan, SE., Dyer, GS., Sodickson, AD., Ketankumar, IP., Khurana, B. (2013). Traumatic elbow injuries: What the orthopedic surgeon wants to know. Radiographics, 33(3), 869-884.
This post was copyedited by Kavish Chandra @kavishpchandra
