What are the differential diagnoses for elbow pain in a patient with unknown age and medical history?

Differential Diagnoses for Elbow Pain

Elbow pain has distinct anatomic patterns that guide diagnosis: lateral epicondylitis is most common overall, but misdiagnosis occurs in 11% of cases, particularly in young patients (≤30 years), those with trauma history, or atypical presentations requiring systematic evaluation of all four anatomic regions (lateral, medial, anterior, posterior). 1

Anatomic Approach to Differential Diagnosis

Lateral Elbow Pain

• Lateral epicondylitis (tennis elbow) is the most frequent cause, presenting with pain at the lateral epicondyle and pain with resisted wrist extension, affecting patients most commonly after age 40 2, 3
• Posterolateral elbow instability is the most common misdiagnosis in the lateral compartment, particularly in younger patients with trauma history 1
• Radial nerve compression/radial tunnel syndrome should be considered when lateral epicondylitis treatment fails, requiring EMG and nerve conduction studies for confirmation 2, 3
• Osteochondral lesions of the capitellum or radial head cause lateral pain with mechanical symptoms (locking, catching) and require MRI evaluation 4, 2
• Radiocapitellar arthritis presents as degenerative lateral pain, identifiable on plain radiographs 2

Medial Elbow Pain

• Medial epicondylitis (golfer's elbow) affects the common flexor-pronator origin, most common between ages 40-60, with pain at the medial epicondyle 5
• Ulnar collateral ligament (UCL) injury is diagnosed by pain with valgus stress testing and positive moving valgus stress test in throwing athletes, with MR arthrography (3T) being most accurate (81% sensitivity, 91% specificity) 5
• Cubital tunnel syndrome presents with ulnar nerve subluxation during elbow flexion/extension and requires T2-weighted MR neurography showing high signal intensity and nerve enlargement 5
• Medial joint line tenderness (distinct from epicondyle) indicates UCL injury rather than epicondylitis 5

Anterior Elbow Pain

• Biceps tendinopathy results from repeated elbow flexion with forearm supination/pronation 3
• Pronator syndrome requires electrodiagnostic studies when neurologic symptoms are present 5

Posterior Elbow Pain

• Olecranon bursitis is the most common cause of posterior elbow pain and swelling, diagnosed by history, physical examination, and bursal fluid analysis to differentiate septic from aseptic causes 3
• Triceps tendinopathy should be considered in the posterior compartment 3

Intra-articular Pathologies (Any Location)

• Intra-articular loose bodies cause mechanical symptoms (locking, clicking, catching) and pain with passive range of motion, distinguishing them from tendinopathy 4, 5
• Osteochondral lesions present with limited range of motion, effusion, and mechanical symptoms, requiring MRI or MR arthrography for stability assessment 4, 5
• Heterotopic ossification causes swelling and limited range of motion, identifiable on plain radiographs 4, 6
• Septic arthritis is characterized by joint effusion with systemic signs of infection, requiring urgent aspiration and culture 6

Red Flags Requiring Immediate Investigation

• Night pain or pain at rest suggests inflammatory or neoplastic process requiring tumor exclusion 5, 2
• Mechanical symptoms (locking, catching) mandate imaging to rule out intra-articular pathology 4, 5
• Neurologic symptoms (paresthesias, weakness) require nerve evaluation with EMG/nerve conduction studies 5
• History of trauma with severe pain out of proportion to clinical findings suggests occult fracture, even with negative initial radiographs 7, 1

High-Risk Profiles for Misdiagnosis

Young age (≤30 years) carries 66.90 odds ratio for misdiagnosis, with trauma history (OR 17.85), limitation of ROM/mechanical symptoms (OR 16.68), and elbow swelling (OR 14.32) being critical warning signs. 1

• Atypical lateral pain location has 90.5% sensitivity for predicting misdiagnosis 1
• Multiple failed corticosteroid injections (OR 2.00 per injection) increase misdiagnosis probability 1
• Limited range of motion with exquisite bony tenderness warrants advanced imaging even with negative radiographs 7

Diagnostic Algorithm

Initial Workup (All Patients)

Plain radiographs of the elbow are mandatory as the first-line imaging study to exclude fractures, tumors, intra-articular bodies, heterotopic ossification, osteochondral lesions, and soft tissue calcification. 4, 5, 6, 2

• Standard AP and lateral views identify osseous pathology in the majority of cases 4, 2
• Comparison views of the contralateral elbow are useful for detecting asymmetry 4, 2

Advanced Imaging (When Radiographs Normal/Nonspecific)

• MRI elbow without contrast is indicated for suspected tendon tear, nerve entrapment, or soft tissue pathology 5, 2
• MR arthrography elbow (3T) is most accurate for UCL tears and osteochondral lesion stability assessment 4, 5
• CT with IV contrast differentiates cellulitis, myositis, tenosynovitis, abscess, and septic arthritis when infection is suspected 6
• Image-guided aspiration with culture is essential when imaging cannot distinguish infected from noninfected fluid collections 6

Electrodiagnostic Studies

• EMG and nerve conduction studies are indicated for cubital tunnel syndrome, pronator syndrome, posterior interosseous nerve syndrome, or radial tunnel syndrome 5, 2

Common Diagnostic Pitfalls

• Overreliance on initial negative radiographs in trauma patients with severe pain—occult fractures (particularly radial head) may require MRI for detection 7
• Failing to obtain radiographs before diagnosing epicondylitis, missing osseous pathology 5, 2
• Assuming all lateral elbow pain is lateral epicondylitis without considering the 11% misdiagnosis rate 1
• Ignoring atypical features such as young age, trauma history, mechanical symptoms, or swelling that dramatically increase misdiagnosis probability 1
• Dynamic fluoroscopy can distinguish stages of collateral ligament injury when clinical instability is suspected 4