What is the differential diagnosis for golfer's elbow, including physical exam findings and relevant workup?

Differential Diagnosis for Golfer's Elbow (Medial Epicondylitis)

Primary Diagnosis

Medial epicondylitis (golfer's elbow) is a degenerative tendinopathy of the common flexor-pronator origin at the medial epicondyle, affecting 1-3.8% of the general population, most commonly between ages 40-60. 1, 2

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Differential Diagnoses with Physical Exam Findings

Medial Compartment Pathologies

Ulnar Collateral Ligament (UCL) Injury

• Physical Exam:
  • Pain with valgus stress testing of the elbow 3
  • Medial joint line tenderness (distinct from epicondyle) 3
  • Positive moving valgus stress test in throwing athletes 3
  • Pain with resisted wrist flexion may be absent (differentiates from medial epicondylitis) 4

Cubital Tunnel Syndrome (Ulnar Nerve Entrapment)

• Physical Exam:
  • Paresthesias in ulnar nerve distribution (ring and small fingers) 5, 4
  • Positive Tinel's sign at cubital tunnel 5
  • Positive elbow flexion test (symptoms with sustained elbow flexion) 5
  • Weakness of intrinsic hand muscles in advanced cases 4
  • Ulnar nerve subluxation with elbow flexion/extension 3, 5

Snapping Triceps Syndrome

• Physical Exam:
  • Palpable or audible snap with elbow flexion/extension 5
  • Medial triceps tendon dislocation over medial epicondyle 3, 5
  • Pain with resisted elbow extension 5

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Intra-articular Pathologies

Osteochondral Lesions (Capitellum or Medial Trochlea)

• Physical Exam:
  • Mechanical symptoms: locking, clicking, catching 3, 6
  • Limited range of motion 3
  • Effusion may be present 6
  • Pain with passive range of motion (differentiates from tendinopathy) 6

Intra-articular Loose Bodies

• Physical Exam:
  • Intermittent locking or catching 3, 6
  • Sudden sharp pain with specific movements 6
  • Palpable loose body occasionally 6

Medial Compartment Arthritis

• Physical Exam:
  • Pain throughout range of motion 6
  • Crepitus with elbow movement 6
  • Loss of terminal extension common 6
  • Night pain or pain at rest (suggests inflammatory process) 6

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Nerve Entrapment Syndromes

Pronator Syndrome (Median Nerve Entrapment)

• Physical Exam:
  • Pain in proximal volar forearm (not at medial epicondyle) 4
  • Paresthesias in median nerve distribution (thumb, index, middle fingers) 4
  • Pain with resisted pronation 4
  • Positive Tinel's sign over pronator teres 4
  • Weakness of flexor pollicis longus and flexor digitorum profundus to index finger 4

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Other Soft Tissue Pathologies

Flexor-Pronator Muscle Strain

• Physical Exam:
  • Acute onset with specific injury 2
  • Pain with resisted wrist flexion and forearm pronation 1
  • Tenderness along muscle belly (not just epicondyle) 2

Medial Epicondyle Avulsion Fracture

• Physical Exam:
  • Acute traumatic onset 6
  • Severe point tenderness over medial epicondyle 6
  • Swelling and ecchymosis 6
  • More common in adolescents (apophyseal injury) 6

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Relevant Workup

Initial Imaging

• Plain radiographs of the elbow are the most appropriate initial imaging study and should be obtained in all patients to rule out osseous pathology. 3, 6, 1
• Standard AP and lateral views can identify:
  • Intra-articular bodies 6, 1
  • Heterotopic ossification 6, 1
  • Osteochondral lesions 6
  • Soft tissue calcification within tendons 6, 1
  • Occult fractures 6, 1
  • Osteoarthritis 6

Advanced Imaging (When Radiographs Normal/Nonspecific)

MRI Elbow Without Contrast

• Indications: Suspected tendon tear, nerve entrapment, or soft tissue pathology with normal radiographs 3, 6, 1
• T2-weighted MR neurography is the reference standard for imaging ulnar nerve entrapment, showing high signal intensity and nerve enlargement. 3
• Can evaluate median and radial nerve entrapment syndromes 3
• Identifies UCL tears, though 3T MR arthrography is more accurate 3

Ultrasound Elbow

• Sensitivity and specificity of 95% and 92% respectively for medial epicondylitis diagnosis 5
• Advantages: Dynamic assessment, operator-dependent 5
• Can assess:
  • Ulnar nerve cross-sectional area and hourglass constriction 3
  • UCL tears (sensitivity 77-79% for partial/full thickness) 3
  • Dynamic nerve subluxation 3, 5
  • Snapping triceps syndrome 3, 5

MR Arthrography Elbow (3T)

• Most accurate for UCL tears: 81% sensitivity, 91% specificity, 88% accuracy 3
• Differentiates partial from complete UCL tears 3
• Reserved for suspected collateral ligament injuries in throwing athletes 3

Stress Radiographs

• Valgus stress views for UCL injury in throwing athletes 3
• Medial joint space opening >3mm suggests UCL insufficiency 3
• Medial joint vacuum phenomenon specific for UCL injury 3

Electrodiagnostic Studies

• EMG and nerve conduction studies indicated when neurologic symptoms suggest cubital tunnel syndrome, pronator syndrome, or posterior interosseous nerve syndrome 6, 4
• Helps localize site of nerve compression 4
• Confirms nerve dysfunction when clinical examination equivocal 4

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Key Clinical Pearls

Red Flags Requiring Further Investigation

• Night pain or pain at rest suggests inflammatory or neoplastic process 6
• Mechanical symptoms (locking, catching) indicate intra-articular pathology 3, 6
• Neurologic symptoms (paresthesias, weakness) require nerve evaluation 6, 4

Common Pitfalls

• Assuming all medial elbow pain is medial epicondylitis without excluding UCL injury or cubital tunnel syndrome 5, 4
• Overreliance on corticosteroid injections without addressing underlying biomechanical issues 1
• Missing concurrent pathologies (e.g., medial epicondylitis with cubital tunnel syndrome) 5, 4
• Failing to obtain initial radiographs to rule out osseous pathology 6, 1