What is the best course of action for a patient with hand and thumb pain, along with tingling in the thumb, following a fall a few weeks ago?

Immediate Diagnostic Evaluation for Post-Traumatic Thumb Tingling

This patient requires plain radiographs immediately to rule out an occult fracture, followed by clinical assessment for carpal tunnel syndrome or nerve injury, as tingling in the thumb following trauma suggests either median nerve compression or a missed fracture with delayed nerve involvement.

Initial Imaging

Obtain radiographs of the hand and wrist with at least 2 views (PA and lateral) as the first imaging study 1. This is the appropriate initial imaging for acute hand or wrist trauma and remains indicated even weeks after injury when symptoms evolve 1.

• If initial radiographs are negative or equivocal but clinical suspicion remains high, repeat radiographs in 10-14 days, or proceed to MRI without IV contrast or CT without IV contrast as equivalent next-step options 1, 2.
• Radiographs must specifically assess for:
  • Fracture fragment displacement >3mm (surgical indication) 3, 2
  • Articular surface involvement >1/3 (surgical indication) 3, 2
  • Small avulsion fractures at the thumb interphalangeal joint base 2

Clinical Assessment for Nerve Involvement

The new-onset tingling in the thumb weeks after trauma strongly suggests median nerve compression (carpal tunnel syndrome) or direct nerve injury 4, 5.

Key Diagnostic Features:

• Median nerve distribution: Numbness/tingling affects the thumb, index, middle, and radial half of ring finger 4, 5, 6
• Durkan maneuver: Apply firm digital pressure across the carpal tunnel; 64% sensitive and 83% specific for carpal tunnel syndrome 4
• Phalen maneuver: Wrist hyperflexion reproducing symptoms 5, 7
• Flick sign: Patient reports shaking hand to relieve symptoms 7

When to Order Electrodiagnostic Studies:

• Obtain electrodiagnostic testing if physical examination findings are atypical or if surgical decompression is being considered (>80% sensitive, 95% specific for carpal tunnel syndrome) 4, 7
• Testing helps differentiate carpal tunnel syndrome from proximal compression or other compressive neuropathies 4

Treatment Algorithm Based on Imaging Results

If Radiographs Show Fracture:

For minimally displaced fractures (<2-3mm):

• Immobilize with thumb spica cast or splint for 3-6 weeks 3, 2
• Obtain follow-up radiographs at 10-14 days to ensure maintained position 2

For displaced fractures (>3mm) or articular involvement (>1/3 surface):

• Surgical intervention is indicated 3, 2

If Radiographs Are Negative (Carpal Tunnel Syndrome):

Initial conservative management:

• Prescribe neutral wrist splinting worn at night - this more than triples the likelihood of improvement at 4 weeks compared to no treatment (RR 3.86,95% CI 2.29 to 6.51) 8
• Splinting provides temporary symptom relief and should be continued for 4-6 months before considering surgery 4, 7

Corticosteroid injection:

• Local corticosteroid injection provides relief for more than one month and delays need for surgery at one year 7
• More effective than splinting alone for moderate symptoms 7

Surgical decompression:

• Offer surgical decompression if symptoms are severe OR if conservative therapy fails after 4-6 months 7
• Surgery should be performed before irreversible motor and sensory changes occur 6
• Endoscopic and open techniques are equally effective, though patients return to work one week earlier with endoscopic repair 7

Critical Pitfalls to Avoid

• Do not assume osteoarthritis without imaging - the trauma history and delayed tingling suggest fracture or acute nerve compression, not chronic degenerative disease 1, 4
• Do not prescribe NSAIDs or acetaminophen as primary treatment for nerve symptoms - these do not address nerve compression and are ineffective for carpal tunnel syndrome 7
• Do not delay electrodiagnostic testing if considering surgery - testing determines severity and surgical prognosis 7
• Do not continue conservative management indefinitely - if symptoms remain severe after 4-6 months of appropriate splinting, escalate to surgical consultation 7