What are the typical presentation and management of ulnar nerve compression at the elbow and wrist?

Ulnar Nerve Compression: Clinical Presentation

Ulnar nerve compression presents differently depending on the anatomical site—at the elbow (cubital tunnel syndrome), symptoms include numbness and tingling in the ring and little fingers with intrinsic hand muscle weakness, while at the wrist (Guyon's canal), presentation varies by zone of compression affecting motor, sensory, or combined function. 1, 2

Presentation at the Elbow (Cubital Tunnel Syndrome)

Sensory Symptoms

• Numbness and tingling in the ulnar distribution (ring and little fingers) is the earliest and most common presenting symptom 3
• Paresthesias along the dorsoulnar hand 3
• Pain and point tenderness at the medial elbow may be present 3

Motor Symptoms

• Weakness of intrinsic hand muscles, particularly affecting fine motor function 4, 3
• Clumsiness of the hand during activities requiring dexterity 3
• Atrophy of the first dorsal interosseous muscle occurs with chronic, untreated compression 3
• Hand weakness that progresses with disease duration 4

Age-Related Presentation Patterns

• Older patients typically present with motor symptoms of chronic onset 3
• Younger patients tend to have more acute symptom onset 3

Physical Examination Findings

• Positive Tinel's sign at the cubital tunnel (tapping over the ulnar nerve elicits paresthesias) 3
• Positive flexion-compression test (symptoms reproduced with elbow flexion and direct pressure) 3
• Palpable thickening of the ulnar nerve with local tenderness along its course 3
• Nerve instability may be present—subluxation or dislocation of the ulnar nerve outside the ulnar groove during elbow flexion 1, 5

Mechanism of Compression

• Static compression occurs through the cubital tunnel retinaculum and Osborne's ligament between the two heads of the flexor carpi ulnaris 1
• Dynamic compression occurs with elbow flexion, particularly when the nerve is unstable 1
• The nerve is subjected to stretch and compression forces that are normally moderated by gliding; when excursion is restricted, a cycle of perineural scarring and progressive nerve damage ensues 2

Presentation at the Wrist (Guyon's Canal)

Zone-Specific Presentations

Compression in Guyon's canal produces different clinical pictures depending on the anatomical zone affected: 2

• Zone 1 (proximal canal): Combined motor and sensory deficits because the nerve is still a single structure containing both fascicle types 2
• Zone 2 (distal canal): Pure motor deficits affecting the deep motor branch 2
• Zone 3 (distal canal): Pure sensory deficits affecting the superficial sensory branch 2

Specific Wrist Findings

• Median nerve compression at the wrist (carpal tunnel syndrome) may occur concurrently due to glycogen deposition in the nerve within the limited space of the carpal tunnel in certain metabolic conditions 6
• Wrist flexion exacerbates compression symptoms 6

Diagnostic Confirmation

Imaging

• Dynamic ultrasound is the preferred initial diagnostic modality to directly visualize ulnar nerve subluxation during elbow flexion 5
• MRI with T2-weighted neurography serves as the reference standard if ultrasound is inconclusive, showing nerve signal intensity and enlargement 5
• CT with axial images in flexion and extension can demonstrate recurrent nerve dislocation 5

Electrodiagnostic Studies

• Electromyography and nerve conduction studies help confirm the diagnosis, particularly in atypical presentations, and differentiate between demyelinating versus axonal injury 5, 3
• Ultrasound and nerve conduction studies may be used in combination with physical exam 3

Management Approach

Conservative Treatment (First-Line)

Conservative treatment for 3-6 months is recommended in patients without significant motor weakness or muscle atrophy: 5

• Maintain neutral forearm position when arm is at side to minimize nerve tension 5
• Avoid elbow flexion beyond 90° as this increases risk of nerve compression and subluxation 5, 6
• Apply proper padding (foam or gel pads) at the elbow to prevent compression, ensuring padding is not too tight to avoid tourniquet effect 5, 6
• Splint immobilization of the elbow and wrist for persistent symptoms 2, 7
• Splinting shows 89% improvement rate (95% CI, 69-99) and is preferred over injections 7
• Steroid/lidocaine injections show 54% improvement rate (95% CI, 41-67) 7

Surgical Indications

Surgery is indicated when: 5

• Conservative treatment fails after 3-6 months
• Progressive motor weakness or muscle atrophy is present at initial evaluation
• Recurrent nerve subluxation/dislocation is documented on dynamic imaging
• Significant sensory deficits persist or worsen

Surgical Options

• If the nerve is stable: In-situ nerve decompression is typically first-line treatment 1
• If the nerve is unstable: Anterior nerve transposition (generally subcutaneous) or medial epicondylectomy 1, 2
• Submuscular transposition is preferred when prior surgery has been unsuccessful 2

Critical Pitfalls

• Do not use padding that is too tight, as this creates a tourniquet effect and paradoxically increases compression risk 5
• Shoulder braces placed over the acromioclavicular joint may increase the risk of brachial plexus neuropathy 6
• Elbow flexion greater than 90° may increase the risk of ulnar neuropathy 6
• CuTS is underdiagnosed due to lack of seeking treatment for symptoms; maintain high index of suspicion 3