What is the management approach for an adult patient with ulnar nerve palsy after a distal radius volar approach open reduction internal fixation (ORIF)?

Management of Ulnar Nerve Palsy After Distal Radius Volar ORIF

Initial observation with serial clinical examination is the recommended approach for most cases of ulnar nerve palsy following distal radius volar ORIF, as these injuries are typically neurapraxic and recover spontaneously within months. 1

Initial Assessment and Mechanism Recognition

The ulnar nerve palsy following distal radius ORIF is most commonly a transient nerve dysfunction that represents the most frequent complication after volar plating, accounting for over half of all nerve-related complications in surgical series 2. The mechanism typically involves:

• High-energy, widely displaced fractures that cause traction or compression injury to the ulnar nerve 1
• Intraoperative positioning or retraction during the volar approach 2
• Rare anatomical displacement where the nerve translocates dorsally around the ulnar head or through a disrupted distal radioulnar joint 3, 4, 5

Clinical Examination Priorities

Document the complete motor and sensory distribution of ulnar nerve function:

• Motor testing: Intrinsic hand muscles (interossei, lumbricals to ring/small fingers), abductor digiti minimi, flexor carpi ulnaris
• Sensory testing: Small finger and ulnar half of ring finger, including two-point discrimination 3
• Associated findings: Check for concurrent median nerve symptoms (acute carpal tunnel syndrome), flexor tendon function abnormalities, or fixed contractures 3, 1

Management Algorithm

For Isolated Ulnar Nerve Palsy (No Open Wound, No Acute Carpal Tunnel Syndrome)

Observation without surgical exploration is recommended 1:

• Serial clinical examinations every 2-4 weeks to document progression or recovery
• Expected timeline: Most patients achieve complete or near-complete recovery by 17 months 1
• Four of five patients in the highest quality case series recovered fully with observation alone 1

Indications for Urgent Surgical Exploration

Proceed immediately to surgical exploration and nerve decompression if 1:

• Concurrent acute carpal tunnel syndrome (median nerve compression symptoms)
• Open wound associated with the fracture or surgical approach
• Progressive neurological deterioration on serial examinations

Indications for Delayed Surgical Exploration

Consider surgical exploration at 3-6 months if 1, 4:

• No clinical improvement in motor or sensory function despite adequate observation period
• High clinical suspicion for nerve entrapment based on mechanism (e.g., persistent symptoms with equivocal imaging suggesting anatomical displacement) 3
• Dense scar tissue formation suspected based on clinical trajectory 4

Surgical Technique When Exploration Is Indicated

When surgical intervention is necessary 3, 1, 4:

• Explore the ulnar nerve from Guyon's canal proximally along its course
• Release any compressive scar tissue or anatomical entrapment
• Reduce any displaced nerve back to its anatomical position if translocated 3, 5
• Consider concurrent median nerve decompression if any symptoms suggest carpal tunnel involvement 3, 1
• Address flexor tendon abnormalities if identified during exploration 3

Expected Outcomes and Counseling

Recovery prognosis is generally excellent 1:

• Complete or near-complete recovery occurs in 80% of cases (4 of 5 patients in the primary case series) 1
• Recovery may take up to 12-17 months for full sensory return and resolution of contractures 3, 1
• Even with moderate residual dysfunction, patients typically return to work without functional limitations 3

Critical Pitfalls to Avoid

• Do not rush to surgical exploration in isolated ulnar nerve palsy without the specific indications listed above, as most cases resolve spontaneously 1
• Do not miss concurrent median nerve compression, which changes management to urgent surgical decompression 1
• Maintain high clinical suspicion for rare anatomical displacement (nerve translocation around ulnar head) if symptoms persist beyond expected recovery timeline 3, 4, 5
• Recognize that surgeon experience matters: Early complications including nerve dysfunction decrease significantly after the first 30 cases, suggesting many are technique-related and potentially avoidable 2