What is the treatment for a subluxation of the ulnar nerve after a motor vehicle accident?

Treatment of Ulnar Nerve Subluxation After Motor Vehicle Accident

Conservative treatment should be tried first for mild to moderate cases of ulnar nerve subluxation, with surgical intervention reserved for severe symptoms, progressive neurological deficits, or failed conservative management after approximately 3 months. 1

Initial Assessment and Diagnosis

• Dynamic ultrasound is the preferred initial imaging modality to demonstrate ulnar nerve subluxation/dislocation 1, 2
• MRI is the reference standard for comprehensive imaging, showing high signal intensity and nerve enlargement on T2-weighted sequences 1
• Assess for neurological deficits including:
  • Sensory changes in the 4th and 5th fingers
  • Motor weakness in intrinsic hand muscles
  • Pain radiating from elbow to forearm

Conservative Management (First-Line Treatment)

1. Immobilization:

   • Broad arm sling for 2-3 weeks to limit elbow flexion 3
   • Avoid positions that trigger subluxation (typically elbow flexion beyond 80 degrees)

2. Patient Education:

   • Avoid prolonged elbow flexion
   • Eliminate direct pressure on the nerve at the elbow
   • Maintain optimal postural alignment 1

3. Pain Management:

   • First-line medications:
     • Calcium channel α2-δ ligands (gabapentin 900-3600 mg/day or pregabalin 300-600 mg/day)
     • Tricyclic antidepressants (nortriptyline or desipramine, 10-75 mg/day)
     • SNRIs (duloxetine 60-120 mg/day or venlafaxine 150-225 mg/day) 1
   • Topical agents (lidocaine patches/creams) for localized pain 1

4. Physical Therapy:

   • Gentle range of motion exercises after initial immobilization period
   • Strengthening of surrounding musculature
   • Techniques to reduce muscle overactivity and fatigue 1

Surgical Management

Surgical intervention is indicated for:

• Severe symptoms unresponsive to conservative measures
• Progressive neurological deficits
• Failed conservative treatment after approximately 3 months
• Significant functional limitation
• Habitual/recurrent ulnar nerve dislocation 1, 4

Surgical Options:

1. Anterior Transposition Techniques:

   • Submuscular or subcutaneous transposition are effective for recurrent subluxation 4
   • Endoscopy-assisted subfascial anterior transposition shows good outcomes with smaller incisions 5

2. Medial Epicondylectomy:

   • Indicated for partial subluxation with shallow retrocondylar groove 6

3. Classification-Based Approach 6:

   • Grade 1 (no/partial subluxation with deep groove): No surgical intervention needed
   • Grade 2 (partial subluxation with shallow groove): Medial epicondylectomy
   • Grade 3 (complete anterior dislocation): Medial epicondylectomy or anterior transposition

Follow-up and Monitoring

• Regular reassessment of pain and function
• Monitor for medication side effects, especially with tricyclic antidepressants
• Adjust treatment based on response 1
• Consider nerve conduction studies to assess for improvement in cases with neurological symptoms

Prognosis

Most patients with traumatic ulnar nerve subluxation respond well to appropriate treatment, with resolution of symptoms and return to full range of pain-free motion at the elbow 3. However, patients with complete nerve dislocation or those with pre-existing compression symptoms may require surgical intervention for optimal outcomes.