Deep peroneal nerve entrapment

Last revised by Henry Knipe on 4 Jan 2022

Deep peroneal nerve entrapment or compression syndrome anterior is a nerve compression syndrome of the deep peroneal nerve and might occur within the anterior tarsal tunnel beneath the inferior extensor retinaculum as anterior tarsal tunnel syndrome.

Deep peroneal nerve entrapment might be seen in athletes and people wearing tight shoes 1-3.

The following sports and activities have an increased risk for the development of deep peroneal nerve entrapment 1,2:

  • dancing
  • football (soccer)
  • skiing
  • running sports
  • martial arts

Other risk factors include 2-4:

  • too tight footwear, immobilization under the metal bar
  • lower extremity edema
  • abnormal posture
  • foot deformities high longitudinal plantar arch or tarsal coalition

The diagnosis including the location of compression might be suspected on clinical grounds and can be confirmed by electrodiagnostic testing such as nerve conduction studies or electromyography 2 or by a diagnostic local nerve block 1. Differential diagnoses such as common peroneal nerve entrapment and chronic exertional compartment syndrome need to be ruled out 2. Imaging such as MRI might provide additional clues concerning the etiology and can rule out differential diagnosis.

Presenting symptoms include sharp pain at the dorsum of the foot with numbness and tingling radiating into the first web space 1-3. There might be a Tinel sign with the percussion of the foot in the respective area leading to tingling in the first web space 2,3.  

Depending on the level of nerve compression symptoms might also include weakness of hallux extension if the entrapment site is above the anterior tarsal tunnel 1 or pain radiating to the lateral aspect of the foot if only the lateral branch is involved 1.

The deep peroneal nerve supplies motor innervation to the tibialis anterior, extensor hallucis longus, extensor digitorum longus, peroneus tertius within the lower leg and extensor hallucis and digitorum brevis muscles at the superolateral aspect of the foot 1,5. Sensory fibers innervate the ankle joint, sinus tarsi the tarsal and second to fourth metatarsophalangeal joints as well as to the first web space 1. Depending on the location of the entrapment or injury this will lead to respective sensory and/or motor symptoms including pain, paresthesia and weakness and possibly denervation changes. Whereas nerve compression above the anterior tarsal tunnel can lead to both motor and sensory symptoms 1 nerve compression within the anterior tarsal tunnel or distal to it typically causes pain and sensory deficits without significant motor loss 3.

Causes of deep peroneal nerve entrapment syndrome include the following 1-5:

Entrapment or injury can happen at several sites above, within or distal to the anterior tarsal tunnel including 1-3:

Weight-bearing radiographs might show structural changes of the foot such as osteophytes 2,3 a high longitudinal arch, osteophytes or a tarsal coalition.

Ultrasound can be used to visualize the deep peroneal nerve at the ankle and dorsum of the foot and can guide percutaneous injection therapy as well as to detect muscle atrophy if present 3.

MRI might visualize the deep peroneal nerve as it divides from the common peroneal nerve at the level of the knee and within the proximal leg proceeding into the anterior compartment descending anterior to the interosseous membrane within a stripe of fatty tissue close to the anterior tibial artery 1. At the foot and ankle, the common site of entrapment MRI can visualize the nerve lateral to the anterior tibial artery and the lateral motor branches deep to the extensor digitorum brevis muscle 4

It can reveal neuroma formation at the entrapment site or possible etiologies as osteophytes or space-occupying lesion which might produce a mass effect on the nerve as well as denervation changes such as muscle edema and fatty atrophy of the extensor hallucis and digitorum brevis muscles 3 even though the latter seems to be uncommon 1. Intrinsic nerve abnormalities as high signal intensity are less reliably visible due to the small size of the nerve 1.

Management includes conservative measures with modification of footwear, custom orthotics or padding as well as nonsteroidal anti-inflammatory drugs and/or corticosteroid injections for pain 2,3. Physical therapy can address ankle instability 2.  Surgery is effective in the setting of compressive lesions and involves an anterior tarsal tunnel release and deep peroneal nerve neurolysis with an open or endoscopic approach 2,3.

Deep peroneal nerve entrapment or anterior tarsal tunnel syndrome was first described by HP Kopell and WA Thompson in 1960 2,6.

The differential diagnosis of deep peroneal nerve entrapment includes 2,3:

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