21-28 days: fibrillation potentials and positive sharp waves on needle EMG
PIN entrapment at Arcade of Frohse
Fibrous arch compresses PIN at proximal supinator
Lipoma, synovitis, ganglion, and radiocapitellar pathology contribute
Radial tunnel is 5 cm segment from radial head to proximal supinator
Therapeutic Considerations
Conservative versus surgical decision framework
Trial of conservative management for 3-4 months in closed injuries
EDX at 3-4 weeks guides prognosis and surgical planning
Brachioradialis recruitment on initial EDX: single best prognostic indicator
Conduction block on NCS: favors neurapraxia with expected recovery
Absent CMAP with denervation on EMG: favors axonotmesis or worse
Nerve regeneration biology
Rate: 1 mm per day or approximately 1 inch per month
Tinel sign advancement confirms regeneration front
Advancing Tinel at 4-week intervals confirms expected recovery trajectory
Reinnervation order: proximal to distal, brachioradialis before intrinsic hand
Timing principles for surgical intervention
Open injuries: exploration within 72 hours
Closed injuries: initial observation 3-4 months, surgery if no recovery
Nerve grafting optimal within 6.9 months; outcomes worsen with delay
Nerve transfer preferred when target muscle denervation exceeds 12 months
Tendon transfer when nerve recovery window has closed
Electrodiagnostic utility
Initial EDX at 3-4 weeks: optimal for injury severity classification
Serial EDX at 3-month intervals: track reinnervation and guide surgical timing
EDX guides selection of neurolysis versus repair versus transfer
Rehabilitation principles
Passive ROM from day 1 to prevent joint contractures
Splinting maintains functional position during reinnervation
Electrical stimulation: evidence limited but may reduce denervation atrophy
Biofeedback and sensory re-education for incomplete recovery
Patient Discharge Instructions
copy discharge instructions
Diagnosis and overview
You have been diagnosed with a radial nerve injury
The radial nerve controls wrist and finger extension and sensation on the back of the hand
Most radial nerve injuries recover with time, splinting, and physiotherapy
Recovery can take weeks to months depending on the type and severity of injury
Splint care
Wear the wrist splint at all times unless bathing or doing exercises
The splint keeps your wrist in the right position to prevent tightening of the tendons
Do not allow the wrist to drop unsupported; this causes contracture
Contact your provider if the splint causes pain, pressure sores, or swelling
Activity and positioning
Avoid sleeping with arm hanging over a chair, sofa arm, or hard surface
Avoid any pressure on the back of the upper arm for prolonged periods
Alcohol can cause or worsen nerve compression; avoid alcohol during recovery
Return to work or sport only as directed by your specialist
Exercise instructions
Perform passive wrist extension and finger extension exercises daily
Use opposite hand to gently extend wrist 10 times, three times per day
Gently straighten each finger using other hand, 10 repetitions per digit
Do not force through significant pain during exercises
Attend all physiotherapy and occupational therapy appointments
Medication instructions
Take pain medication as prescribed
Do not exceed recommended doses of ibuprofen or acetaminophen
Report any dizziness, confusion, or excessive drowsiness from nerve pain medications
Follow-up appointments
Attend outpatient appointment with neurology or hand surgery as scheduled
Nerve conduction study should be arranged 3-4 weeks after injury
Bring the splint to all follow-up appointments for assessment
Return to emergency department immediately if
New or worsening weakness in the arm or other limb
Worsening numbness or complete loss of feeling
Increasing pain, swelling, redness, or warmth in the arm (possible infection or compartment syndrome)
Pain with passive stretching of the fingers (compartment syndrome warning)
Fingers become cold, pale, or blue (vascular compromise)
Any new weakness in the shoulder, other arm, or legs
References
Guidelines and key sources
Sinthuwong C, Katirji B. Radial Mononeuropathy: Clinical and Electrodiagnostic Characteristics in 177 Patients. Muscle and Nerve. 2026
Largest prospective EDX-characterized cohort; spiral groove most common site (89%)
External compression 40%, humeral fractures 18% of cases
Brachioradialis full recruitment: 100% good outcome predictor
Ilyas AM, Mangan JJ, Graham J. Radial Nerve Palsy Recovery With Fractures of the Humerus: An Updated Systematic Review. Journal of the American Academy of Orthopaedic Surgeons. 2020
Spontaneous recovery 77-90% of fracture-associated palsies
Early exploration within 3 weeks: 89.8% recovery rate
Recovery probability falls sharply after 12 months without improvement
Schwaiger K, Abed S, Russe E, et al. Management of Radial Nerve Lesions After Trauma or Iatrogenic Nerve Injury: Autologous Grafts and Neurolysis. Journal of Clinical Medicine. 2020
Neurolysis: 98% achieved grade 3 or greater motor recovery
Primary or secondary repair: 83-91% good outcomes
Nerve grafting optimal timing 6.9 months or less post-injury
Silver S, Ledford CC, Vogel KJ, Arnold JJ. Peripheral Nerve Entrapment and Injury in the Upper Extremity. American Family Physician. 2021
Conservative management guidelines and surgical indications
PIN syndrome differentiating features and management
Robinson LR. How electrodiagnosis predicts clinical outcome of focal peripheral nerve lesions. Muscle and Nerve. 2015
EDX prognostic criteria and outcome prediction framework
Conduction block as favorable prognostic sign
Steenbeek ED, Pondaag W, Tannemaat MR, et al. Optimal timing of needle electromyography to diagnose lesion severity in traumatic radial nerve injury. Muscle and Nerve. 2023
EMG optimal at 3-4 weeks for fibrillation potentials and severity classification
Krijnen NA, Comerci AJ, Head LK, et al. What Is the Probability of Radial Nerve Recovery After Surgical Repair of Humerus Fractures Accounting for Time Since Injury? Clinical Orthopaedics and Related Research. 2026
Recovery probability falls to 17% if no recovery by 12 months post-injury
Ahmed KS, Rajput BU, Siddiqui MAI, Nadeem A, Rahman MF. Median to Radial Nerve Transfer: An 8-Year Experience. Journal of Surgical Research. 2023
M4+ wrist extension in all patients after median to radial nerve transfer
Optimal timing within 6 months of injury
Bateman EA, Pripotnev S, Larocerie-Salgado J, Ross DC, Miller TA. Assessment, management, and rehabilitation of traumatic peripheral nerve injuries for non-surgeons. Muscle and Nerve. 2025
Rehabilitation framework and non-surgical management principles
Mauermann ML, Staff NP. Peripheral Neuropathy. Journal of the American Medical Association. 2026
Peripheral neuropathy differential diagnosis and systematic evaluation
SymptomDx is an educational tool for medical professionals. It does not replace clinical judgment. Verify all clinical data and drug dosages with authoritative sources.