What is the comprehensive management for a patient presenting with acute wrist drop from a non‑traumatic radial nerve palsy, without any wound?

Comprehensive Management of Non-Traumatic Radial Nerve Palsy with Wrist Drop

For acute wrist drop from non-traumatic radial nerve palsy without a wound, initiate immediate wrist splinting in neutral position and begin structured physical therapy within the first week, while simultaneously investigating the underlying cause through nerve conduction studies and imaging to rule out compressive lesions. 1, 2

Immediate Initial Management

Splinting and Positioning

• Apply a dynamic wrist splint immediately to maintain the wrist in neutral position (0-15 degrees extension) to prevent contractures and preserve hand function during recovery. 3, 4
• The splint should support wrist extension while allowing finger movement to maintain tendon gliding and prevent stiffness. 4

Early Physical Therapy Initiation

• Begin rehabilitation within the first week of diagnosis, focusing on passive range of motion exercises for the wrist and fingers to prevent joint stiffness and maintain tendon excursion. 3, 4
• Implement active-assisted exercises for the unaffected muscles to maintain overall hand function and prevent compensatory patterns. 4

Diagnostic Workup to Identify Etiology

Essential Nerve Studies

• Obtain nerve conduction studies of the radial nerve to confirm the diagnosis, localize the level of injury, and establish baseline severity for monitoring recovery. 5, 2
• The appropriate management depends primarily on accurate determination of cause, severity, duration, and level of involvement. 2

Imaging to Rule Out Compressive Causes

• Order MRI of the upper extremity without contrast if there is suspicion of nerve compression from soft tissue masses, tumors, or anatomical variants. 2
• Consider MRI of the brain if there are any atypical features, central neurological signs, or absence of peripheral nerve findings on electrodiagnostic studies, as cerebral peduncle infarcts can rarely present as isolated wrist drop. 5

Systemic Evaluation

• Screen for diabetes mellitus, as microvascular disease can cause radial nerve palsy similar to other mononeuropathies. 3, 2
• Evaluate for history of external compression (blood pressure cuff injury, "Saturday night palsy"), neuritis, or malignant tumor formation. 3, 2

Structured Physical Therapy Protocol

Phase 1: Acute Phase (0-6 Weeks)

• Perform passive range of motion exercises for wrist extension, finger extension, and thumb extension 3-4 times daily to prevent contractures. 4
• Use electrical stimulation to the wrist and finger extensors to maintain muscle bulk and prevent atrophy during the denervation period. 4
• Maintain splinting at all times except during therapy sessions. 3, 4

Phase 2: Recovery Phase (6 Weeks to 3-5 Months)

• Progress to active-assisted exercises as motor recovery begins, typically starting with wrist extensors followed by finger and thumb extensors. 3, 4
• Implement strengthening exercises once antigravity movement returns, gradually increasing resistance. 4
• Continue dynamic splinting but allow periods of splint-free activity as strength improves. 4

Functional Training Throughout

• Incorporate activities of daily living training early, using adaptive equipment and compensatory strategies as needed. 4
• Focus on grip strengthening and fine motor coordination as recovery progresses. 4

Timeline for Surgical Decision-Making

Expectant Management Period

• Continue conservative management with splinting and physical therapy for 3-5 months, as this is the standard of care for closed, non-traumatic radial nerve injuries. 1, 2
• Monitor for clinical signs of recovery monthly, including return of wrist extension strength and improvement in electrodiagnostic studies. 1, 2

Indications for Surgical Exploration

• If there is no evidence of nerve recovery by 3-5 months post-injury, surgical exploration and reconstruction is recommended. 1
• Surgical options include direct nerve repair, nerve grafting, or nerve and tendon transfers depending on intraoperative findings and the likelihood of achieving functional recovery. 1, 2

Critical Pitfalls to Avoid

Do Not Delay Splinting

• Failure to immediately splint the wrist leads to rapid development of flexion contractures and secondary joint stiffness, which significantly impairs functional outcomes even after nerve recovery. 4

Do Not Assume Peripheral Cause Without Confirmation

• Always obtain nerve conduction studies, as central causes (cerebral peduncle infarcts) can present identically to peripheral radial nerve palsy but require completely different management. 5

Do Not Wait Beyond 5 Months for Surgical Referral

• Delaying surgical exploration beyond 5 months significantly reduces the success rate of nerve reconstruction and may necessitate tendon transfers instead of nerve repair. 1, 2

Do Not Neglect Functional Training

• Physical therapy focused solely on passive range of motion without incorporating functional activities and strengthening results in poor return to activities of daily living even with complete motor recovery. 4

Expected Outcomes with Full Therapy

• With appropriate splinting and physical therapy initiated early, most patients with non-traumatic radial nerve palsy show significant improvement in muscle strength, range of motion, pain relief, and functional independence within 3-4 months. 3, 4
• Complete recovery of wrist extensor power to normal levels typically occurs within 4 months when conservative management is successful. 3