Deep peroneal nerve entrapment is associated with nerve-type pain in the foot. It will typically display pain over the top of the foot between the first and second metatarsal. Patients will describe it as spontaneous sporadic pain which is not proportional to the clinical findings. Meaning, it is never really associated with any edema, erythema, ecchymosis, or clinical signs that would normally be present for such pain. It is sometimes aggravated by shoe gear which rubs on the top of the foot and irritates the deep peroneal nerve.
It is also sometimes associated with overactivity of the extensor tendons from a new or recent exercise program. It will typically also be painful at night in bed when the foot is plantarflexed causing some stretching of the nerve. It can also be associated with prior trauma to the top of the foot in the area of the deep peroneal nerve. The nerve pain will typically radiate distally to the toes, especially the great toe. On occasion, it can radiate to the lateral, outside portion of the foot, in an area that normally would not be suspected of the deep peroneal nerve. It is comparable to someone who bangs their funnybone on the elbow. Although the elbow was traumatized it will cause significant pain and temporary weakness to the fingers and hand. Nerve pain is very different than musculoskeletal pain. Musculoskeletal pain often occurs with trauma or injury to muscles, tendons, or bones. This is usually associated with localized edema and predictable pain and symptoms in the area of trauma. Nerve pain will usually radiate from the particular area of entrapment to all the areas of the foot without showing many signs of the irritation source except for symptoms of pain.
As well as many other nerve entrapment syndromes, the diagnosis of deep peroneal nerve entrapment is very much a clinical diagnosis based on the clinician’s experience with this syndrome. It is often not detected in nerve conduction studies. To build a diagnosis the clinicians need to listen carefully to the symptoms described. It will often have been present on and off for many years. It can radiate causing distributing pain to areas other than the site of the entrapment. One of the best diagnostic tools is to administer a local anesthetic injection to the deep peroneal nerve in the first interspace where it usually is entrapped by the extensor hallucis brevis tendon. This will immediately relieve the patient’s symptoms. They will go from not being able to stand on their toes to having normal function and pain relief once the pain source from the deep peroneal nerve is relieved with a local anesthetic injection. This is used as a diagnostic tool for deep peroneal nerve entrapment syndrome. Unfortunately, injections in this area are often not very therapeutic. The pain will soon return when the local anesthesia wears off. To relieve the symptoms permanently a small surgical procedure is involved to remove a portion of the extensor hallucis brevis tendon at the myotendinous junction and a 1 cm distal section. Further decompression of the nerve can be performed based on visual constrictions in the area at the time of surgery, risk needed. This is usually a very rewarding surgery with a very low complication rate. Healing from the surgery usually only requires healing the skin incision without much disruption of lifestyle except that he must use a postoperative shoe for approximately 10 days.