What is the cause of involuntary movements of the right thumb, index, and middle finger after right wrist triangular fibrocartilage complex (TFCC) and distal radioulnar joint (DRUJ) repair?

Involuntary Finger Movements After TFCC and DRUJ Repair: Nerve Injury Until Proven Otherwise

The involuntary movements of the thumb, index, and middle finger following TFCC and DRUJ repair most likely represent iatrogenic injury to the dorsal sensory branch of the ulnar nerve (DSBUN), which is a recognized complication of this surgery that typically resolves spontaneously within weeks to months.

Primary Etiology: Dorsal Sensory Branch of Ulnar Nerve Injury

• DSBUN neuroapraxia is a documented complication of arthroscopic TFCC foveal repair, occurring in approximately 10% of cases (5 of 48 patients in one series), with all cases demonstrating full spontaneous recovery 1
• The dorsal sensory branch of the ulnar nerve is anatomically vulnerable during DRUJ and TFCC surgical approaches, particularly when accessing the foveal region or placing suture anchors 1
• Neuroapraxia manifests as abnormal sensory phenomena or involuntary movements in the distribution of the affected nerve, which for DSBUN includes the ulnar aspect of the hand and potentially affects motor coordination of the thumb, index, and middle fingers through sensory feedback disruption 1

Alternative Neurological Causes to Consider

• Complex Regional Pain Syndrome (CRPS) can develop after distal radius and DRUJ procedures, presenting with involuntary movements, tremor, or dystonia in the affected digits 2, 3
• CRPS should be suspected if involuntary movements are accompanied by disproportionate pain, swelling, temperature changes, or skin color changes 2
• Median nerve irritation from surgical swelling or positioning could theoretically affect thumb, index, and middle finger function, though this would be less common with isolated TFCC/DRUJ repair 2

Immediate Evaluation Algorithm

Step 1: Clinical Assessment

• Examine for sensory deficits in the ulnar nerve distribution (dorsal ulnar hand, small finger, ulnar half of ring finger) 1
• Assess for signs of CRPS: temperature asymmetry, color changes, allodynia, disproportionate pain 2, 3
• Evaluate DRUJ stability and check for persistent instability that could cause ongoing nerve irritation 1, 4

Step 2: Rule Out Surgical Complications

• Obtain radiographs to ensure hardware position is appropriate and no malposition is causing nerve compression 3
• Assess for unremitting pain, which warrants immediate reevaluation per consensus guidelines 2, 3

Step 3: Determine Need for Advanced Imaging

• MRI without contrast is appropriate if CRPS is suspected or if symptoms persist beyond expected neuroapraxia recovery timeline (typically 3-6 months) 2
• MRI can identify nerve compression, persistent DRUJ instability, or soft tissue complications 2

Management Approach

Conservative Management (First-Line)

• Immediate active finger motion exercises are mandatory to prevent the functionally disabling complication of finger stiffness, which is extremely difficult to treat once established 2, 5, 3
• Finger motion does not adversely affect adequately stabilized TFCC/DRUJ repairs and should begin immediately postoperatively 2, 5, 3
• For isolated DSBUN neuroapraxia, expectant management with reassurance is appropriate, as spontaneous full recovery occurs in all documented cases 1

Monitoring Timeline

• DSBUN neuroapraxia typically resolves within weeks to months without intervention 1
• Any patient with unremitting pain during follow-up must be reevaluated for complications including DRUJ instability, malunion, or CRPS 2, 3
• If involuntary movements persist beyond 3-6 months or worsen, advanced imaging and possible nerve conduction studies are warranted 1

Critical Pitfalls to Avoid

• Never restrict finger motion in response to involuntary movements, as this leads to severe stiffness requiring extensive therapy or additional surgery 2, 5, 3
• Do not dismiss persistent or worsening symptoms as "normal postoperative course"—unremitting pain or progressive neurological symptoms require immediate reevaluation 2, 3
• Failure to recognize early CRPS can lead to chronic disability; maintain high index of suspicion if symptoms seem disproportionate to expected recovery 2
• Delayed return to function may indicate concomitant pathology such as persistent DRUJ instability or extensor carpi ulnaris tendinosis that requires additional treatment 4

Expected Recovery

• With appropriate patient selection and surgical technique, TFCC foveal repair resolves DRUJ instability in 92% of patients (44 of 48) with significant improvement in pain and function 1
• Return to previous work and sport activities occurs in 85.5% of patients after arthroscopic TFCC repair 1
• DSBUN neuroapraxia, when it occurs, resolves completely without permanent sequelae in all reported cases 1