When can a patient with radial nerve weakness expect to see improvement in wrist strength?

Recovery Timeline for Radial Nerve Weakness and Wrist Strength

Most patients with radial nerve weakness after humeral fracture surgery will recover wrist extension strength within 7 months, with a 56% probability of recovery by 18 months even if no improvement is seen at 7 months. 1

Expected Recovery Timeline

The probability of spontaneous recovery remains favorable through the first 7 months post-injury, with 90% of radial nerve injuries ultimately recovering without surgical intervention. 1 However, if no recovery occurs by 12 months, the probability drops significantly to only 17% chance of eventual recovery. 1

Month-by-Month Recovery Expectations:

• 0-3 months: Anterior cervical decompression studies show rapid relief of weakness within 3-4 months for nerve compression injuries, suggesting early recovery is possible for neuropraxic injuries. 2
• 3-6 months: The critical window where most recoverable nerve injuries demonstrate improvement. 1
• 6-7 months: If no recovery by 7 months, there remains a 56% probability of recovery by 18 months. 1
• 12 months: If still no recovery at one year, probability drops to 17% for eventual recovery. 1
• 18 months: The endpoint for expecting spontaneous recovery; surgical intervention should be strongly considered before this point. 1

Immediate Management to Optimize Recovery

Apply a dorsal cock-up splint positioning the wrist in 20-30 degrees of extension immediately upon diagnosis. 3 This splint must be padded and comfortably fitted without being constrictive. 3

Critical Early Motion Protocol:

• Begin active finger motion exercises immediately from the time of diagnosis to prevent finger stiffness, which is the most functionally disabling complication. 3
• Finger motion exercises do not adversely affect nerve recovery and significantly impact patient outcomes. 3
• The splint should only stabilize the wrist, never restrict finger motion. 3
• Maintain full active range of motion in all unaffected joints throughout treatment. 3

Common pitfall: Rigid immobilization of fingers leads to severe stiffness requiring extensive therapy or surgical intervention after it develops. 3

Adjunctive Therapies During Recovery Period

Functional electrical stimulation (FES) should be initiated within the first 6 months post-injury for patients with impaired wrist muscle contraction. 4 FES produces improved muscle force in wrist extension and short-term increases in motor strength and control. 4

• FES is recommended by the American Heart Association as adjunctive therapy to motor practice for wrist motor impairment. 4
• The presence of voluntary finger extension is a positive prognostic indicator for upper extremity motor recovery. 4

Factors That Do NOT Affect Recovery Timing

No patient or injury characteristics predict faster or slower recovery, including age, fracture location, presence of vascular injury, or type of surgical fixation. 1 This means all patients should be counseled using the same probability timeline regardless of these factors.

When to Consider Surgical Intervention

Because recovery probability remains relatively high for at least 7 months, early nerve surgery is unlikely to be beneficial. 1

Surgical Decision Algorithm:

• Before 7 months: Continue conservative management with splinting, FES, and active motion exercises unless there is documented nerve disruption. 1
• 7-12 months without recovery: Begin discussing nerve reconstruction, nerve transfers, or tendon transfers as recovery probability is declining. 1
• After 12 months without recovery: Strongly recommend surgical intervention (nerve transfers or tendon transfers) as spontaneous recovery probability is only 17%. 1
• Unremitting pain or new symptoms at any point: Immediate reevaluation required as this may indicate nerve compression or other complications. 5

Surgical Options When Recovery Fails:

Median to radial nerve transfers can restore wrist, finger, and thumb extension with excellent outcomes when performed up to 10 months after injury. 6 This technique transfers the flexor digitorum superficialis nerve to the extensor carpi radialis brevis nerve for wrist extension, and the flexor carpi radialis nerve to the posterior interosseous nerve for finger and thumb extension. 6

Monitoring for Recovery

Watch for the ability to extend the wrist against gravity (Medical Research Council grade ≥3) as the primary marker of meaningful motor recovery. 1 This functional milestone indicates sufficient strength return for activities of daily living.