What is ulnar nerve pain also known as?

Ulnar Nerve Pain: Cubital Tunnel Syndrome

Ulnar nerve pain is most commonly known as "cubital tunnel syndrome" (CuTS), which is the second most common peripheral nerve entrapment neuropathy after carpal tunnel syndrome. 1, 2

Clinical Presentation

• Patients typically present with numbness and tingling in the ring and small fingers, which is often the earliest sign of cubital tunnel syndrome 1
• Pain and point tenderness at the medial elbow (the "funny bone") may be present 1
• Advanced cases may present with weakness or atrophy of the intrinsic hand muscles, particularly affecting the first dorsal interosseus muscle 1
• Older patients tend to present with motor symptoms of chronic onset, while younger patients tend to have more acute symptoms 1

Diagnostic Approach

Physical Examination

• Motor testing should assess finger abduction/adduction, thumb adduction, and flexion of 4th and 5th digits 3
• Tinel's sign and flexion-compression tests at the elbow can help diagnose cubital tunnel syndrome 1
• Palpation of the ulnar nerve for thickening and local tenderness along the nerve pathway is recommended 3

Imaging

• MRI without IV contrast is the reference standard for imaging ulnar nerve entrapment, with T2-weighted MR neurography showing high signal intensity and nerve enlargement 4, 5
• Ultrasound is an effective alternative with high accuracy rates (sensitivity 77-79%, specificity 94-98%) for assessing cross-sectional area and nerve thickness 4, 3
• Dynamic ultrasound is particularly useful for demonstrating nerve dislocation in ulnar nerve neuropathy 5
• Shear-wave elastography has shown 100% specificity and sensitivity for diagnosing ulnar neuropathy at the elbow 4

Management

Conservative Treatment

• Maintain neutral forearm position when arm is at side and limit arm abduction to 90° in supine position to prevent ulnar nerve entrapment 4
• Avoid excessive elbow flexion beyond 90° as this increases risk of ulnar neuropathy 4, 3
• Patient education about avoiding prolonged flexion postures or repeated elbow flexion motions can provide relief in early stages 6
• Elbow splints and night-gliding exercises may be used for conservative management 1
• Paracetamol (up to 4g/day) is recommended as first-line oral analgesic for pain management 4

Surgical Treatment

• Surgical intervention is indicated if conservative treatment fails or if signs of sensory and/or motor deficit are present 6
• For stable ulnar nerves, in-situ nerve decompression is typically done as first-line treatment 6
• For unstable nerves, anterior nerve transposition (generally subcutaneous) or more rarely, a medial epicondylectomy can be performed 6
• Simple decompression and decompression with transposition are equally effective in idiopathic ulnar nerve entrapment, even in severe cases 7
• Decompression with transposition is associated with more wound infections than simple decompression 7

Prevention of Complications

• Avoid prolonged pressure on the postcondylar groove of the humerus (ulnar groove) 4, 3
• Periodic assessment of upper extremity position during procedures is essential to prevent complications 4
• If left untreated, chronic ulnar nerve compression can lead to atrophy of the intrinsic hand muscles and affect quality of life 1

Common Pitfalls

• Failure to distinguish between ulnar nerve entrapment under the humero-ulnar arcade (cubital tunnel) from nerve injury at the retro-epicondylar groove 2
• Misdiagnosis as "ulnar neuropathy at the elbow," which is non-specific, or incorrect diagnosis of "cubital tunnel syndrome" 2
• Main causes of treatment failure include neuroma of a branch of the medial cutaneous nerve of the forearm, nerve instability, and persistence of a compression point 6