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Peroneal Nerve Injury

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Other Names

  • Deep Peroneal Nerve Injury
  • Superficial Peroneal Nerve Injury
  • Common Peroneal Nerve Injury
  • Peroneal Neuropathy
  • Peroneal nerve compromise
  • Peroneal Neuropraxia
  • Foot drop



  • PNI following ankle sprain first described by Hyslop in 1941[1]


  • One study found Peroneal Nerve Injuries were the most common lower extremity neuropathy in athletes[2]
  • Of 303 patients preventing with foot drop, 31% were found to be due to peroneal neuropathy[3]
  • Nerve involvement
    • Krivickas et al found the majority of cases were CPN or proximal DPN[2]




  • Knee Dislocation
    • CPN Palsy is seen in 5-40% of knee dislocations[4]
  • Proximal Fibula Fracture
  • Proximal Tibia Fracture
  • Tibial Plateau Fracture
    • Estimated 1% incidence (need citation)
  • ACL Injury, less commonly other ligamentous injuries
  • Ankle Fracture
  • Ankle Sprain
    • Occurs due to traction to the peroneal nerve at the fibular head due to stretching of the peroneal muscles[5]
    • One study found 86% of patients with grade III, 17% of grade II had EMG evidence of peroneal nerve injury, with the vast majority resolving at 3 months follow up[6]
  • Direct trauma
    • Examples include direct impact, penetrating trauma, laceration
    • Most commonly this is around the fibular head where the nerves are most superficial


  • Arthroscopic meniscal repair
  • Realignment of the knee extensor mechanism
  • Knee Arthrodesis
  • Total Knee Replacement
  • Treatment of knee flexion contracture
  • Posterior Short Leg Splint or Posterior Short Leg Cast
    • Can damage the peroneal nerve by pressure over the fibular head
    • Mitigated by padding the cast or splint in the area of the fibular head
  • Tight compression or bandage
  • Position during anesthesia or surgery


  • Mass effect
    • Ganglion Cyst or Bakers Cyst is a common mass lesion associated with PNI, specifically the CPN[7]
    • Bakers Cyst was the most common cause of PNI by mass effect in a study by Kim et al[8]
    • Tumors in order of decreasing frequency, included schwannoma, neurofibroma, osteochondroma, neurogenic sarcoma, focal hypertrophic neuropathy, desmoid tumor, and glomus tumor
  • Knee Osteoarthritis
    • Several case reports, including one with varus laxity[9]
  • Habitual leg crossing
  • Prolonged bed rest


Risk Factors

Differential Diagnosis

Differential Diagnosis Leg Pain

Differential Diagnosis Neuropathy

Clinical Features

  • History
    • Typically complain of lateral lower limb and dorsal foot pain
    • Concurrent low back pain or posterolateral thigh pain suggests L5 radiculopathy
    • Pain usually precedes sensory changes in a similar distribution
    • Patient may complain of foot drop as the first manifestation of this disorder.
  • Physical Exam: Physical Exam Leg
    • Careful sensory examination can localize the lesion
    • PNI should have sensory and motor deficits limited to the calf, ankle and foot
    • Involvement of the knee or anything proximal suggests sciatic nerve, lumbosacral radiculopathy
  • CPN
    • Sensory: Lateral calf and dorsum of foot (sparing lateral and plantar foot)
    • Weakness: Ankle dorsiflexion and eversion, toe extension
  • DPN
    • Sensory: Area between great and second toes
    • Weakness: Ankle dorsiflexion, partial eversion > inversion, toe extension
  • SPN
    • Sensory: Lateral calf and dorsum of foot (sparing lateral foot)
    • Weakness: Ankle eversion
  • Special Tests
    • Tinels Test: tapping around the fibular head may reproduce symptoms




  • Need minimum of 3T MRI to view peroneal nerve
  • Knee/ Ankle
    • Consider MRI knee in all cases since intraneural ganglia may be the most common cause[14]
    • Look for bony lesion, neural ganglia
  • Lumbar
    • Look for evidence of L5 radiculopathy


  • Assess fibular head


  • Helpful with
    • confirm diagnosis of peroneal neuropathy
    • Exclude alternative diagnoses
    • Prognosticate
  • Evaluation should include
    • Motor nerve conduction studies of the peroneal nerve, tibial nerve
    • Sensory nerve conduction studies of the sural, superficial peroneal nerves
  • Findings
    • If demyelination, focal slowing or conduction block
    • If axon loss, compound muscle action potential amplitudes will be decreased
  • If abnormal, must examine nerves supplied by L5 nerve root but not by peroneal nerve
    • Includes Tibialis Posterior, medial gastrocnemius,
    • Expand differential of radiculopathy, lumbosacral plexopathy, sciatic neuropathy


The Sunderland Classification of Peripheral Nerve Injuries

  • Grade 1: Conduction block +/- segmental demyelination
  • Grade 2: Axon discontinuity with intact endoneurium
  • Grade 3: Axon and endoneurium discontinuity with intact perineurium
  • Grade 4: Axon, endoneurium and perineurium discontinuity with intact epineurium
  • Grade 5: Nerve discontinuity
  • Grade 6: Mixed nerve injury



  • Indications
    • Vast majority of cases
    • No clearly identified mass or lesion which could be surgically excised


  • General
    • Neuropathic pain is challenging to treat
    • Consider the following agents which should be individualized to the patient
  • Topical lidocaine
  • Capsaicin
  • Selective serotonin reuptake inhibitors
  • Antiepileptics
  • Opioids
  • μ-receptor agonists
  • Heat Therapy
    • If any sensory loss, be careful to avoid thermal damage
  • Ice Therapy
    • If any sensory loss, be careful to avoid thermal damage
    • Case report suggested ice applied to the fibular head lead to a peroneal nerve palsy[15]


  • Ankle Foot Orthosis
    • Necessary if unable to dorsiflex ankle
    • Seen with proximal deep peroneal neuropathy, common peroneal nerve
  • Rocker Bottom Shoe
    • Consider if weakness of the toe extensors only (distal deep peroneal neuropathy)
    • Can be used to optimize gait, reduce energy for ambulation
  • Lateral wedge
    • Consider if isolated superficial peroneal nerve palsy
    • Prevent supination from weak eversion

Other Modalities

  • Iontophoresis
  • Physical Therapy
    • Useful in subtle peroneal nerve injuries to help with recovery
    • If complete nerve transection or axonal loss, strengthening is not helpful, PROM may
    • Maintain ROM important to avoid heel cord contracture
  • Peroneal Nerve Stimulator
    • Require an intact functioning peroneal nerve
    • Not useful in patients with peripheral nerve injury.
  • Wound checks
    • Patients with sensory loss should check their feet daily to prevent progression of ulcers


  • Indication
    • Mass or lesion causing neuropathy
    • Refractory pain
    • Inability to ambulate with AFO due to contracture
  • Technique
    • Surgical repair or graft
    • Tibialis posterior tendon transfer (to restore active dorsiflexion)
    • Neurolysis (for chronic pain)

Rehab and Return to Play


  • Stretching/ ROM
    • Important to stretch daily to prevent contracture, maintain ambulatory status
    • Patient often cant tolerate bracing if contracture develops

Return to Play/ Work

  • Needs to be updated

Complications and Prognosis


  • Prognosis varies widely and is dependent on etiology
  • Following Knee Dislocation
    • Complete palsy holds a worse prognosis than incomplete palsy[16]
  • Following Total Knee Arthroplasty
    • Park et al found 62% of patients had maximal recovery, 38% had complete recovery at 12 months[17]
  • Those requiring surgical management
    • 84% of patients who underwent end-to-end suture repair received good recovery by 24 months[18]
    • Of those who required grafts, under 6 cm had 75% recovery of function


  • Ankle contracture
  • Equinovarus foot deformity
  • Need for surgery

See Also


  1. Hyslop G. Injuries to the deep and superficial peroneal nerves complicating ankle sprain. Am J Surg. 1941;11(2):436–8.
  2. 2.0 2.1 2.2 Krivickas, Lisa S., and Asa J. Wilbourn. "Peripheral nerve injuries in athletes: a case series of over 200 injuries." Seminars in neurology. Vol. 20. No. 02. Copyright© 2000 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel.:+ 1 (212) 584-4662, 2000.
  3. Langenhove M, Pollefliet A, Vanderstraeten G. A retrospective electrodiagnostic evaluation of footdrop in 303 patients. Electromyogr Clin Neurophysiol. 1989;29:145–52.
  4. Robertson A, Nutton RW, Keating JF (2006) Dislocation of the knee. J Bone Joint Surg Br 88:706–711
  5. McCrory P, Bell S, Bradshaw C. Nerve entrapments of the lower leg. Sports Med. 2002;32(6):371–91.
  6. Nitz AJ, Dobner JJ, Kersey D. Nerve injury and Grades II and II ankle sprains. Am J Sports Med. 1985;13(3):177–82.
  7. Spinner RJ, Atkinson JL, Tiel RL. Peroneal intraneural ganglia: the importance of the articular branch. A unifying theory. J Neurosurg. 2003;99:330–43.
  8. Kim DH, Murovic JA, Teil RL, Kline DG. Management and outcomes in 318 operative common peroneal nerve lesions at the LSU Health Sciences Center. Neurosurgery. 2004;54:1421–9.
  9. Fetzer GB, Prather H, Gelberman RH, Clohisy JC. Progressive peroneal nerve palsy in a varus athritic knee. JBJS. 2004;86-A(7):1538–40.
  10. Jenkins DB. The Leg. In: Hollinshead’s functional anatomy of the limbs and back. 8th ed. Philadelphia: WB Saunders; 2002. pp. 327–50.
  11. Togrol E. Bilateral peroneal nerve palsy induced by prolonged squatting. Mil Med. 2000;165(3):240–2.
  12. Katirji MB, Wilbourn AJ. Common peroneal mononeuropathy: a clinical and electrophysiologic study of 116 lesions. Neurology. 1988;38:1723–8
  13. Fukuda H. Bilateral peroneal nerve palsy caused by intermittent pneumatic compression. Intern Med. 2006;45(2):93–4.
  14. Kim JY, Ihn YK, Kim JS, Chun KA, Sung MS, Cho KH. Non-traumatic peroneal nerve palsy: MRI findings. Clin Radiol. 2007;62:58–64.
  15. Moeller JL, Munroe J, McKeag DB. Cryotherapy induced common peroneal nerve palsy. Clin J Sports Med. 1997;7:212–6.
  16. O'Malley MP, Pareek A, Reardon P, Krych A, Stuart MJ, Levy BA. Treatment of Peroneal Nerve Injuries in the Multiligament Injured/Dislocated Knee. J Knee Surg. 2016 May;29(4):287-92.
  17. Park, Jai Hyung, et al. "Common peroneal nerve palsy following total knee arthroplasty: prognostic factors and course of recovery." The Journal of arthroplasty 28.9 (2013): 1538-1542.
  18. Poage, Chad, Charles Roth, and Brandon Scott. "Peroneal nerve palsy: evaluation and management." JAAOS-Journal of the American Academy of Orthopaedic Surgeons 24.1 (2016): 1-10.
Created by:
John Kiel on 7 July 2019 07:26:38
Last edited:
4 October 2021 15:12:03