What are the appropriate diagnostic tests for elbow pathology?

Diagnostic Tests for Elbow Pathology

Radiography should be the initial imaging modality for all patients with elbow pain, followed by advanced imaging based on specific clinical findings and suspected pathology. 1

Initial Diagnostic Approach

• Plain radiographs are the first-line imaging for elbow pain evaluation, capable of identifying intra-articular bodies, heterotopic ossification, osteochondral lesions, soft tissue calcification, occult fractures, and osteoarthritis 1
• Comparison with the asymptomatic contralateral elbow is often useful for better evaluation 1
• Stress radiographs can detect medial joint line opening and asymmetry when evaluating for valgus instability 1

Advanced Imaging Based on Clinical Presentation

For Chronic Elbow Pain with Mechanical Symptoms (locking, clicking, limited range of motion)

• MR arthrography offers highest sensitivity (100%) and specificity (67%) for detecting intra-articular bodies and evaluating osteochondral lesion stability 1
• CT arthrography provides excellent assessment of heterotopic ossification, loose bodies (sensitivity 93%, specificity 66%), and osteoarthritis 1
• Standard MRI can detect loose bodies (especially on T2-weighted images), enlarged synovial plica, and osteochondral lesions 1
• Standard CT is useful for evaluating heterotopic ossification, loose bodies, and osteophytosis 1

For Medial Elbow Pain with Snapping and Swelling

• MRI provides high sensitivity (90-100%) for detecting medial epicondylitis and ulnar collateral ligament injuries 2
• T2-weighted MR neurography is the reference standard for imaging ulnar nerve entrapment, showing high signal intensity and nerve enlargement 1, 2
• Dynamic ultrasound can demonstrate nerve dislocation during elbow movement in cases of ulnar nerve neuropathy and snapping triceps syndrome 1, 2

For Lateral Epicondylitis (Tennis Elbow)

• MRI shows high inter- and intraobserver reliability with 90-100% sensitivity and 83% specificity for epicondylalgia 3
• Ultrasound with advanced techniques (sonoelastography, superb microvascular imaging) has sensitivity of 94% and specificity of 98% for diagnosing common extensor tendon tears 3

Diagnostic Algorithm for Elbow Pathology

1. Initial evaluation: Plain radiographs (AP, lateral, and oblique views) 1, 4
2. If radiographs are normal or nonspecific:
   • For suspected intra-articular pathology: MR arthrography or CT arthrography 1
   • For suspected occult stress fracture or bone abnormality: MRI or CT without contrast 1
   • For suspected nerve entrapment: MRI or ultrasound 1, 2
   • For suspected epicondylitis: MRI or ultrasound 3, 4

Common Pitfalls and Considerations

• MRI without contrast may be insufficient for complete evaluation of collateral ligament injuries; MR arthrography may provide better accuracy 2
• Normal anatomic variants may be misinterpreted as pathologic on imaging 2
• CT is superior for detailed bony anatomy assessment, while MRI excels at soft tissue evaluation 2, 4
• Pain may be referred from cervical spine pathology or radial tunnel syndrome, requiring broader diagnostic consideration when initial imaging is negative 3, 5
• MRI has limitations in detecting cartilage abnormalities, with accuracy reported as 45% for the radius, 64% for the capitellum, 18% for the ulna, and 27% for the trochlea 1