Ulnar Neuropathy at the Elbow

Ulnar neuropathy at the elbow is compression or traction injury to the ulnar nerve at the elbow. It occurs most often in the cubital tunnel beneath the aponeurosis of flexor carpi ulnaris or behind the medial epicondyle in the ulnar groove. It produces numbness and paraesthesia in the ring and little fingers and, in advanced cases, hand weakness and wasting.

• Second most common compressive neuropathy of the upper limb after carpal tunnel syndrome; incidence about 20 to 25 per 100 000 person years; more common in men.
• Causes:
  • Sustained elbow flexion (sleeping, phone use, driving), leaning on the elbow, and repetitive flexion in work or sports (throwing).
  • Old elbow fractures (tardy ulnar palsy), cubitus valgus, osteoarthritis and bone spurs, ganglion or tumour, and nerve subluxation.
  • Rheumatoid arthritis, anaesthesia positioning, diabetes, alcohol, and thin body habitus.
• Natural history: mild intermittent symptoms usually resolve with conservative measures; persistent compression leads to axonal loss and wasting.

• Intermittent numbness and tingling in the ring finger (ulnar half) and little finger, worse with elbow flexion (holding phone, sleeping) and at night; may include medial elbow pain.
• Dorsal ulnar hand sensation is affected (dorsal ulnar cutaneous branch leaves the nerve about 5 to 8 cm proximal to the wrist), which differs from ulnar neuropathy at the wrist.
• Weakness of grip, difficulty with pinch, dropping objects, clumsy fine motor control (buttons, keys).
• Signs:
  • Tinel sign over the cubital tunnel.
  • Positive elbow flexion test (full flexion with wrist extended for 60 seconds reproduces symptoms).
  • Froment sign (thumb interphalangeal flexion on key pinch from weak adductor pollicis), Wartenberg sign (little finger abduction), and Jeanne sign.
  • Interosseous wasting and first dorsal interosseous guttering.
  • Ulnar claw hand (ring and little fingers) in severe disease.
  • Weak finger abduction and adduction.
  • Reduced sensation in the ulnar distribution including the dorsal ulnar hand.
• Ulnar claw may be less marked with lesions at the elbow because flexor digitorum profundus to ring and little fingers is also weak (the ulnar paradox).
• Subluxation of the nerve over the medial epicondyle on elbow flexion can be palpable.

• Clinical, with nerve conduction studies and EMG confirming localisation (slowing of conduction velocity across the elbow, conduction block, reduced amplitude) and severity; essential before surgery.
• High resolution ultrasound for enlarged nerve, subluxation, mass, and anatomy; MRI for mass or ambiguous cases.
• Elbow X-ray (including cubital tunnel view) for trauma, deformity, arthritis or bone spur.
• Blood tests: HbA1c, vitamin B12, TSH, ESR, CRP, rheumatoid factor if indicated.
• Differentials:
  • C8 or T1 radiculopathy (neck pain, weakness of median innervated thumb muscles).
  • Thoracic outlet syndrome, lower brachial plexus lesion, and Pancoast tumour (Horner syndrome).
  • Ulnar neuropathy at the wrist (Guyon canal, sparing dorsal ulnar sensation and flexor digitorum profundus).
  • Motor neurone disease, polyneuropathy, syringomyelia, and medial epicondylitis.

Conservative (first 3 to 6 months for mild to moderate symptoms)

• Education and elbow protection: avoid leaning on the elbow, prolonged elbow flexion (holding a phone, driving with elbow bent), and repetitive extreme flexion; use a hands free headset and padded elbow protector.
• Night splint or soft elbow pad to keep the elbow near 45 degrees of flexion (for example a rolled towel wrapped around the elbow) for 3 months; this reduces symptoms in many patients.
• Nerve gliding exercises and activity modification; ergonomic review of work and sport technique.
• Analgesia: paracetamol 1 g up to four times daily; ibuprofen 400 mg three times daily with food for up to 2 weeks.
• Neuropathic pain agents: amitriptyline 10 to 50 mg at night; gabapentin 300 mg at night to 300 to 600 mg three times daily; pregabalin 75 mg twice daily; renal dose adjustment.
• Correct contributing conditions: glycaemic control, alcohol cessation, vitamin B12 replacement (hydroxocobalamin 1 mg intramuscularly if deficient).
• Corticosteroid injection into the cubital tunnel is not generally advised (risk to nerve and little benefit).

Surgery

• Indications: progressive or persistent sensory symptoms beyond 3 to 6 months of conservative treatment; motor weakness, wasting or muscle atrophy; severe conduction block or axonal loss on nerve studies; a structural cause (mass, bone spur, arthritis); recurrent subluxation.
• Procedures: simple decompression (in situ release), medial epicondylectomy, or anterior transposition (subcutaneous or submuscular); outcomes are similar for simple decompression and transposition in most patients. Sensory recovery is good in about 70 to 90 percent in mild disease; motor and severe cases recover less completely.
• Hand therapy after surgery to restore strength and prevent stiffness.

Follow up

• Review at 6 to 12 weeks; reassess power (grip, pinch, interossei) and sensation.
• Refer to a hand or peripheral nerve surgeon if there is wasting, motor weakness or deterioration, as delayed treatment leads to permanent deficit.