What do you know about cubital tunnel syndrome?

Cubital Tunnel Syndrome: Clinical Overview

Cubital tunnel syndrome is the second most common peripheral nerve compression syndrome after carpal tunnel syndrome, caused by compression of the ulnar nerve as it passes through the cubital tunnel at the elbow. 1, 2

Anatomical Considerations

The cubital tunnel is a fibro-osseous structure consisting of three distinct components, not just the retrocondylar groove as commonly misunderstood: 2, 3

• The retrocondylar groove (posterior to the medial epicondyle) 2
• The cubital tunnel retinaculum (ligamentum arcuatum or Osborne ligament) that partially covers the groove 2
• The humeroulnar arcade and deep flexor/pronator aponeurosis distally 2, 3

The syndrome can be classified into primary forms (including anterior subluxation of the ulnar nerve and compression from an anconeus epitrochlearis muscle) and secondary forms caused by elbow joint deformities or other pathological processes. 2, 3

Clinical Presentation

Early Symptoms

The earliest and most common presenting symptom is numbness and tingling in the ring and small fingers, along with the dorsoulnar aspect of the hand. 1, 4

Progressive Manifestations

• Paresthesias in the ulnar nerve distribution 1
• Hand clumsiness and weakness affecting fine motor function 1
• Pain and point tenderness at the medial elbow 1
• Muscle atrophy, particularly of the first dorsal interosseous muscle in chronic untreated cases 1
• Hand contractures in advanced disease 5

Age-Related Presentation Patterns

• Older patients typically present with motor symptoms of chronic onset 1
• Younger patients tend to have more acute symptom onset 1

Etiology and Risk Factors

Common causes include: 1, 2

• Repetitive elbow pressure or flexion 1
• Stretching or trauma to the elbow joint 1
• History of elbow joint injury 1
• Cubitus valgus deformity 2, 3
• Anterior subluxation of the ulnar nerve 2

Diagnostic Approach

Clinical Examination

Physical examination findings include: 1, 2

• Tinel's sign at the cubital tunnel 1
• Flexion-compression test 1
• Palpation of the ulnar nerve for thickening or local tenderness 1
• Assessment for muscle atrophy in the hand intrinsics 1

Electrodiagnostic Studies

Nerve conduction studies are typically used to confirm the clinical diagnosis. 2, 3

Imaging Modalities

Radiography should be the initial imaging study for chronic elbow pain to identify intra-articular bodies, heterotopic ossification, osteochondral lesions, soft tissue calcification, occult fractures, or osteoarthritis. 6

Advanced imaging options include: 2, 3, 4

• Ultrasound to visualize morphological changes in the nerve within the cubital tunnel 1, 2
• MRI to show morphological changes and nerve compression 2, 3, 4

Differential Diagnosis

Critical conditions to exclude: 2, 3

• C8 radiculopathy 2, 3
• Pancoast tumor 2
• Pressure palsy 2
• Double crush syndrome (concurrent compression at multiple sites) 3

Treatment Algorithm

Conservative Management

Conservative treatment should be considered in early-stage cubital tunnel syndrome and consists of avoiding external pressure on the elbow and applying night splints. 2, 3

Specific conservative measures include: 6, 1

• Rest and activity modification 6
• Elbow splints or braces to prevent flexion 1
• Nerve-gliding exercises 1
• Avoidance of repetitive elbow flexion and direct pressure 2

Surgical Indications

Surgery should be recommended when conservative treatment fails, or when patients present with motor weakness, muscle atrophy, or fixed sensory changes. 2, 3

Surgical Options

According to randomized controlled studies, simple in situ decompression is the treatment of choice for primary cubital tunnel syndrome. 2, 3

In Situ Decompression

• Must extend at least 5-6 cm distal to the medial epicondyle 2, 3
• Can be performed via open or endoscopic technique under local anesthesia 2, 3
• Also appropriate for uncomplicated ulnar luxation and most post-traumatic or secondary forms 2, 3

Anterior Transposition

Indications for transposition include: 2, 3, 5

• Painful ulnar nerve luxation where the nerve "snaps" over the medial epicondyle 2
• Severe bony or tissue changes of the elbow, especially cubitus valgus 2, 3
• Scarring (submuscular transposition preferred to provide healthy vascular bed) 2

Subcutaneous or submuscular transposition techniques are available, with submuscular preferred when scarring is present. 2, 5

Critical Surgical Pitfalls

• Insufficient proximal or distal nerve mobilization can cause kinking 2, 3
• Compromise of blood flow to the nerve during transposition 2
• Both complications may require revision surgery 2

Medial Epicondylectomy

This technique is not commonly performed, particularly in German-speaking countries. 2, 3

Prognosis and Complications

Chronic ulnar nerve compression, when left untreated, can lead to irreversible first dorsal interosseous muscle atrophy and significantly impair quality of life, preventing participation in daily activities requiring fine motor function. 1, 5

Recurrence of ulnar nerve compression at the elbow may occur following surgical treatment. 2, 3

Epidemiology

Up to 5.9% of the general population have experienced symptoms of cubital tunnel syndrome, though the condition is underdiagnosed due to lack of treatment-seeking for symptoms. 1