A patient who fell and now has elbow pain has a normal elbow radiograph except for a joint effusion; what is the appropriate next step in evaluation and management?

Management of Elbow Effusion After Trauma with Normal Radiographs

MRI without contrast is the recommended next imaging study for this patient, as an elbow joint effusion in the setting of trauma with normal radiographs is highly suspicious for an occult fracture that requires further evaluation. 1

Immediate Clinical Assessment

Before proceeding to advanced imaging, assess the patient's active range of motion:

• Preserved active ROM in all planes (flexion, extension, pronation, supination) has 97% specificity for absence of fracture, making radiographically occult fracture very unlikely 2
• Any limitation of active ROM is 100% sensitive for fracture or effusion, strongly supporting the need for MRI 2
• Point tenderness at the olecranon, epicondyles, or radial head increases suspicion but is less specific 2

Advanced Imaging Recommendation

MRI without contrast is the appropriate next step for several compelling reasons:

• MRI is as sensitive as 3-phase bone scan for detecting occult fractures but provides superior soft tissue detail, making it the preferred modality 3, 1
• MRI demonstrates bone marrow edema and periosteal fluid at fracture sites, which are the hallmark findings of occult injury 3
• T2-weighted sequences are particularly valuable for evaluating joint effusions and associated pathology 1
• Research demonstrates that 75-100% of adults with post-traumatic elbow effusion and normal radiographs have occult fractures on MRI, with the radial head being the most common site (87%) 4, 5

Why MRI Without Contrast Specifically

Contrast administration offers no advantage for initial evaluation of traumatic elbow effusion:

• Non-contrast MRI is sufficient for detecting bone marrow edema, occult fractures, and ligament injuries 1
• MRI with contrast is reserved for specific indications like evaluating intra-articular bodies and osteochondral lesion stability, not acute trauma 1
• Using contrast unnecessarily adds cost, time, and potential adverse effects without improving diagnostic yield 1

Expected MRI Findings

When MRI is performed, anticipate:

• Bone marrow edema is present in 90-100% of cases with traumatic effusion, even when fracture lines are not visible 4, 5
• Radial head fractures account for approximately 87% of occult elbow fractures 5
• Associated soft tissue injuries occur in 15-20% of cases, including collateral ligament disruptions and loose bodies 5
• The broad spectrum of injuries identified often extends beyond what is clinically suspected 5

Common Pitfalls to Avoid

Do not assume all elbow effusions represent fractures:

• While 75-100% of adults have occult fractures, pediatric studies show only 17% have true fractures on follow-up 6
• Other causes include ligament injuries and synovial pathology that may not require fracture-specific management 1

Do not rely solely on effusion size to predict fracture:

• The degree of anterior or posterior fat pad displacement does not correlate with likelihood of underlying fracture 5
• A small effusion can still indicate significant injury 5

Management Implications

Initial conservative management is appropriate while awaiting MRI:

• Immobilization with a posterior splint in 90 degrees of flexion protects against displacement of occult fractures 1
• Ice application and NSAIDs for symptomatic relief 7
• Avoid activities that stress the elbow until imaging is complete 7

The MRI results will directly impact definitive management, as identification of specific fracture patterns, ligament injuries, or other soft tissue pathology determines whether conservative treatment, orthopedic referral, or surgical intervention is needed 1, 8