What is the best treatment for a patient with a radial nerve lesion causing wrist drop?

Management of Radial Nerve Lesion with Wrist Drop

A dorsal cock-up splint (static wrist extension splint) is the appropriate initial orthotic intervention for radial nerve palsy causing wrist drop, maintaining the wrist in 20-30 degrees of extension while allowing immediate active finger motion exercises to prevent stiffness. 1, 2

Immediate Orthotic Management

Static wrist extension splinting is the foundation of conservative management:

• Apply a dorsal cock-up splint that positions the wrist in 20-30 degrees of extension to facilitate functional hand use 1, 2
• The splint should be padded and comfortably tight but not constrictive 2
• This positioning allows the patient to achieve functional grip through tenodesis effect 3

Consider dynamic orthotic options for enhanced function:

• A high-profile dynamic forearm-based wrist-finger-thumb assistive-extension orthosis can provide extension assistance to wrist, thumb, and fingers simultaneously 4
• Tenodesis extension splinting allows patients to extend fingers and thumb via wrist flexion, maximizing functional use during nerve regeneration 3
• Dynamic orthoses have demonstrated improved grip strength and functional status, even allowing patients to resume complex activities like playing guitar 4

Critical Early Motion Protocol

Begin active finger motion exercises immediately:

• Active finger motion exercises must be performed from diagnosis to prevent finger stiffness, which is one of the most functionally disabling adverse effects 1, 2
• Finger motion does not adversely affect the injury and provides significant impact on patient outcome 1, 2
• Hand stiffness can be very difficult to treat after it develops, requiring multiple therapy visits and possibly surgical intervention 1, 2
• All unaffected joints should maintain full active range of motion throughout the treatment period 2

Diagnostic Workup to Guide Treatment

Determine the level and severity of nerve injury:

• Perform nerve conduction studies to confirm radial nerve involvement and differentiate axonal from demyelinating lesions 5, 6
• High-resolution ultrasound can visualize nerve pathology including constriction, torsion, or structural abnormalities that may require surgical intervention 5
• MRI brain should be obtained if clinical features suggest central rather than peripheral etiology (absence of sensory changes, associated neurological signs) 6

The anatomic level of injury determines prognosis and surgical options:

• High radial nerve injuries (above the spiral groove) have longer regeneration distances and may benefit from nerve transfers 7
• Posterior interosseous nerve injuries spare wrist extension but affect finger and thumb extension 3, 7

Surgical Decision Algorithm

Early surgical intervention is indicated when:

• High-resolution ultrasound reveals nerve torsion or structural constriction amenable to decompression 5
• Complete nerve transection is identified on imaging or exploration 7
• No clinical or electrodiagnostic evidence of recovery occurs by 3-4 months post-injury 7

Nerve transfers offer advantages over traditional approaches:

• For high radial nerve injuries, nerve transfers from median nerve branches to wrist and finger extensors provide shorter regeneration distances compared to nerve repair or grafting 7
• Nerve transfers can be performed earlier than tendon transfers, typically within 6 months of injury 7
• This approach avoids the functional limitations and donor site morbidity associated with tendon transfers 7

Duration and Follow-up

Splinting duration depends on nerve recovery:

• Continue orthotic support throughout the nerve regeneration period, which can be lengthy and variable 3
• Serial clinical examinations every 4-6 weeks to assess for return of voluntary wrist extension 7
• Repeat nerve conduction studies at 3-4 months if no clinical recovery to guide surgical decision-making 5, 7

Common Pitfalls to Avoid

Do not over-immobilize the hand:

• Rigid immobilization of fingers leads to unnecessary stiffness and poor functional outcomes 2
• The splint should only stabilize the wrist, not restrict finger motion 1, 2

Do not assume all wrist drops are peripheral:

• Central causes (cerebral peduncle infarcts) can mimic radial nerve palsy but require completely different management 6
• Normal nerve conduction studies with persistent wrist drop should prompt brain imaging 6

Do not delay surgical consultation beyond 3-4 months:

• Prolonged denervation leads to irreversible muscle atrophy and poor outcomes from delayed nerve reconstruction 7
• Early identification of surgical candidates through appropriate imaging and electrodiagnostic testing is critical 5, 7