What are the differential diagnoses for elbow pain, the appropriate physical examination maneuvers, the initial management plan, and the indications for imaging before referring to orthopaedic surgery?

Differential Diagnoses for Elbow Pain

Lateral epicondylitis (tennis elbow) is the most common cause of elbow pain, but you must systematically exclude septic arthritis, fractures, nerve entrapment syndromes, medial epicondylitis, olecranon bursitis, biceps/triceps tendon ruptures, heterotopic ossification, intra-articular loose bodies, and tumors before settling on a tendinopathy diagnosis. 1, 2

Key Differential Diagnoses

Most Critical to Exclude First

• Septic arthritis: Joint effusion with systemic signs of infection (fever, elevated inflammatory markers), requires urgent aspiration and culture 2
• Fractures: Must be excluded with plain radiographs, including avulsion fractures at tendon attachment sites 1, 2
• Tumors: Must be excluded with initial imaging 2

Common Soft Tissue Pathology

• Lateral epicondylitis (tennis elbow): Pain at lateral epicondyle with resisted wrist extension, caused by degenerative microtearing of extensor carpi radialis brevis origin 3, 4
• Medial epicondylitis (golfer's elbow): Less common than lateral (4:1 to 7:1 ratio), involves flexor-pronator origin 4
• Olecranon bursitis: Posterior elbow swelling without intra-articular involvement, effacement of fat planes 5, 2
• Biceps tendon rupture: Middle-aged males, sudden eccentric contraction event, palpable defect in antecubital fossa 4
• Triceps tendon rupture: Rare, forceful eccentric contraction, avulsion from olecranon 4

Nerve Entrapment Syndromes

• Radial tunnel syndrome: Pain with resisted supination and long finger extension 6
• Posterior interosseous nerve compression: Weakness without sensory changes 6
• Ulnar nerve entrapment: Medial elbow pain with paresthesias in ulnar distribution 6

Other Structural Pathology

• Heterotopic ossification: Swelling with limited range of motion, visible on plain films 1, 2
• Intra-articular loose bodies: Mechanical symptoms with intermittent swelling and locking 2
• Osteochondral lesions: May present with swelling and mechanical symptoms 2

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Physical Examination Maneuvers

For Lateral Epicondylitis (Tennis Elbow)

• Resisted wrist extension test: Pain at lateral epicondyle with wrist extension against resistance (most specific test) 3, 6
• Resisted middle finger extension (Maudsley's test): Pain with resisted long finger extension suggests radial tunnel involvement 6
• Palpation: Tenderness directly over lateral epicondyle, approximately 1 cm distal to epicondyle at extensor origin 3
• Grip strength testing: Weakened grip strength compared to contralateral side 3

For Medial Epicondylitis

• Resisted wrist flexion and pronation: Pain at medial epicondyle with resisted flexion/pronation 4
• Palpation: Tenderness over medial epicondyle at flexor-pronator origin 4

For Olecranon Bursitis

• Inspection: Visible posterior elbow swelling, assess for warmth, erythema (suggests infection) 5
• Palpation: Fluctuant swelling over olecranon, assess for tenderness 5

For Biceps Tendon Rupture

• Palpation: Palpable defect in antecubital fossa, "Popeye" deformity with proximal muscle retraction 4
• Hook test: Inability to "hook" index finger under intact biceps tendon from lateral side with elbow flexed 90 degrees 4

For Nerve Entrapment

• Tinel's sign: Percussion over ulnar nerve at cubital tunnel for ulnar neuropathy 6
• Resisted supination: Pain with resisted supination suggests radial tunnel syndrome 6

For Joint Instability

• Valgus stress test: Assess medial collateral ligament integrity with elbow at 30 degrees flexion 7
• Varus stress test: Assess lateral collateral ligament complex with elbow at 30 degrees flexion 7

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Imaging Strategy Before Orthopaedic Referral

Initial Imaging (Always Required)

Plain radiographs of the elbow are mandatory as the first imaging study to exclude fractures, heterotopic ossification, osteoarthritis, avulsion fractures at tendon attachment sites, intra-articular loose bodies, tumors, and joint effusions suggesting occult fractures. 1, 2

• Obtain AP, lateral, and oblique views of the elbow 1
• Comparison with contralateral elbow can identify subtle asymmetry 7

When to Proceed with Advanced Imaging

Do NOT proceed to MRI or other advanced imaging without first completing at least 4-6 weeks of appropriate conservative management, as early imaging is unnecessary and may lead to overtreatment. 1

Indications for MRI (Without IV Contrast)

• Symptoms persist or worsen after 4-6 weeks of conservative treatment 1
• Need to evaluate for occult soft tissue pathology, tendon degeneration, or nerve entrapment 1, 2
• Suspicion of UCL injury, lateral collateral complex injury, or osteochondral lesion 2
• Assessment of loose bodies or synovial abnormalities 2

Indications for CT

• Better characterization of heterotopic ossification if surgical planning becomes necessary 1
• Assessment of complex fracture patterns 7

Indications for CT with IV Contrast

• When imaging cannot distinguish infected from noninfected fluid collections 2
• To assess soft tissue extent and differentiate cellulitis, myositis, tenosynovitis, abscess, and septic arthritis 2

No Role for These Studies

• Bone scintigraphy has no role in initial evaluation 7, 1
• Contrast-enhanced MRI is not indicated for initial elbow strain evaluation 1

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Initial Management Plan (Before Orthopaedic Referral)

First-Line Conservative Management (0-6 Weeks)

Conservative management successfully resolves symptoms in approximately 80% of cases within 3-6 months, so aggressive initial conservative therapy is warranted before considering referral. 1

Activity Modification

• Relative rest avoiding aggravating activities, but never completely immobilize the elbow to prevent muscle atrophy 1, 5
• Avoid repetitive wrist extension and supination movements 3

Pain Control

• Topical NSAIDs are preferred over oral NSAIDs in elderly patients to provide effective pain relief while avoiding gastrointestinal, renal, and cardiovascular risks 1
• Ice application for 10-minute periods through a wet towel for short-term pain relief 1, 5
• Oral NSAIDs provide short-term pain relief but do not alter long-term outcomes 5

Supportive Measures

• Tennis elbow band (counterforce bracing) worn 2-3 cm distal to lateral epicondyle 6
• Compression wrap or semirigid supports for traumatic injuries 2

Physical Therapy

• Eccentric strengthening exercises are the cornerstone of rehabilitation, promoting tendon healing through tensile loading that stimulates collagen production 1
• Stretching exercises for wrist extensors 1
• Progressive strengthening exercises as tolerated 2

Second-Line Treatments (4-12 Weeks)

Corticosteroid Injections

• May provide short-term relief but should be used with caution, especially in elderly patients 1, 5
• Do not alter long-term outcomes and may inhibit healing 1, 5
• Local injection (24 mg betamethasone with 1% lidocaine) may be more effective than oral NSAIDs for acute-phase pain 5
• Avoid systemic steroids for localized conditions 5

Alternative Modalities

• Therapeutic ultrasound may decrease pain and increase collagen synthesis, though evidence is weak 1

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When to Refer to Orthopaedic Surgery

Absolute Indications for Urgent Referral

• Suspected septic arthritis (requires immediate arthrocentesis with culture, empiric antibiotics, potential surgical debridement) 2
• Complete biceps or triceps tendon rupture (traditionally treated surgically with good results) 4
• Unstable fractures or fracture-dislocations 2
• Gross instability on stress testing (frank redislocation) 7

Indications for Elective Referral

• Pain persists despite 6-12 months of well-managed conservative treatment 1, 5
• Mechanical symptoms from intra-articular loose bodies 2
• Heterotopic ossification causing mechanical symptoms or persistent pain refractory to conservative management 1
• Progressive neurological deficits from nerve entrapment 6

Surgical Options for Lateral Epicondylitis

• Excision of abnormal tendon tissue and longitudinal tenotomies 1
• Débridement of extensor carpi radialis brevis tendon via percutaneous, arthroscopic, or open approaches 3, 8
• Reserved for carefully selected patients who have failed conservative therapy 5

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Common Pitfalls to Avoid

• Do not assume all lateral elbow pain is tennis elbow—systematically exclude septic arthritis, fractures, and nerve entrapment first 2, 6
• Do not order MRI before completing 4-6 weeks of conservative treatment unless there are red flags suggesting serious pathology 1
• Do not completely immobilize the elbow, as this leads to muscle atrophy and stiffness 1
• Do not rely on corticosteroid injections as primary treatment—they provide only short-term relief and do not change long-term outcomes 1, 5
• Do not delay treatment initiation—longer symptom duration before treatment is associated with treatment failure 5
• Do not use oral corticosteroids for localized elbow conditions in elderly patients due to unnecessary systemic side effects 5