Management of Inability to Fully Extend the Elbow After Trauma

Initial Clinical Assessment

Plain radiographs are the standard first‑line imaging for acute elbow trauma and the inability to fully extend the elbow is highly sensitive for an underlying fracture. 1, 2
Axial‑loading mechanisms (e.g., impact on an outstretched arm) most often produce radial‑head/neck fractures, which account for roughly 50 % of adult elbow fractures. 1, 2
The validated elbow‑extension test is performed with the patient seated, shoulders flexed to 90°, and the patient asked to actively extend the elbow. A positive test (inability to fully extend) signals a high likelihood of bony injury. 3, 4
Visible joint effusion (swelling, inability to extend) is a strong indicator of intra‑articular pathology. 1, 2

Obtain standard anteroposterior and lateral elbow radiographs immediately; they are the first‑line modality for all acute elbow injuries. 1, 5, 2
Posterior and anterior fat‑pad elevation on the lateral view denotes joint effusion and suggests an occult fracture even when a fracture line is not seen. 1, 2
The most common fracture patterns after axial loading are radial‑head/neck, olecranon, and coronoid‑process fractures. 1, 2
Avulsion fractures at tendon or ligament attachment sites may also be present on plain films. 1, 2

If the patient cannot fully extend the elbow but plain radiographs are normal or indeterminate, a non‑contrast CT of the elbow should be performed. 3, 4, 5
CT identifies occult fractures in approximately 12.8 % of patients with a positive elbow‑extension test and normal radiographs. 3, 4
CT is especially valuable for detecting radial‑head, olecranon, and coronoid‑process fractures that are missed on plain films. 3, 4
CT provides detailed information on fragment size, displacement, and angulation that directly influences surgical planning. 3, 4
When clinical suspicion is lower and the patient can be safely observed, repeat radiographs in 10–14 days are an acceptable alternative. 5

When radiographs and CT are normal but the extension limitation persists, obtain an MRI (without IV contrast) or an ultrasound to evaluate ligamentous, tendinous, or muscular injury. 4, 5
MRI is superior for detecting injuries of the lateral collateral ligament complex, medial collateral ligament tears, and tendon disruptions. 4
Ultrasound can identify triceps‑tendon ruptures and certain ligamentous injuries, although evidence for its use in acute trauma remains limited. 4, 5

Radial‑head fractures, Essex‑Lopresti injuries, and Monteggia fracture‑dislocations each require specific surgical approaches. 3, 4
Assessment for associated elbow dislocation or instability is essential; a coronoid fracture often indicates a prior dislocation with ligamentous injury. 1, 2
Complex injury patterns to recognize include the “terrible triad” (radial‑head fracture, coronoid fracture, elbow dislocation), posterior fracture‑dislocation, and trans‑olecranon fracture‑dislocation. 1, 3, 2

Do not rely solely on initial radiographs; occult fractures are frequent when the elbow cannot be fully extended. 3, 4
Do not delay advanced imaging (CT or MRI) in patients with persistent inability to extend; early CT reduces missed fractures and improves outcomes. 3, 4
Always evaluate for associated soft‑tissue injuries, especially ligamentous disruption, when a fracture is identified. 1, 2

After a closed reduction of a posterior elbow dislocation, clinicians should perform a systematic test for residual instability using fluoroscopic imaging or a bedside clinical exam to detect any remaining laxity. 6
Measurement of joint widening on stress imaging guides the severity classification: widening ≤ 10° denotes slight instability, widening > 10° denotes moderate instability, and any frank redislocation indicates severe instability. 6

Practitioners must actively search for concomitant fractures of the radial head, coronoid process, or medial epicondyle, because the presence of any of these injuries upgrades a simple dislocation to a complex injury that requires a different therapeutic approach. 7

In patients with a confirmed lateral epicondyle avulsion fracture on plain radiographs, CT adds only detailed information about fragment size and displacement and does not alter surgical decision‑making because the instability is driven by ligamentous injury, not by the small bony fragment【8】.
CT without IV contrast is appropriate only when plain radiographs are normal or indeterminate and an occult fracture is suspected; it is not indicated for cases where the fracture is already visualized【8】.
The American College of Radiology (ACR) Appropriateness Criteria state that there is no evidence supporting CT for the assessment of tendon, ligament, or muscle injury in this clinical scenario【8】.

MRI (non‑contrast) provides a reliable assessment of soft‑tissue injury, showing good agreement with stress fluoroscopy for grading ligamentous damage and predicting poor outcomes if surgical stabilization is omitted【9】.

Both statements are derived from the 2024 ACR guideline literature; the documents do not assign a formal strength grade, but they are presented as the current standard of care by the American College of Radiology.