| Feb 02, 2015
By Jonathan T. Finnoff, D.O., FACSM
A 19-year-old soccer player goes to a physician’s office complaining of medial leg pain. The patient describes the pain as a deep, aching, burning pain with a severity of 0-8/10 that is exacerbated by running and relieved with rest. Occasionally, the pain radiates into the medial foot and can be associated with paresthesias (numbness or burning type sensations) in the same distribution. On physical examination, the athlete has no tenderness to palpation, benign findings on knee and ankle examinations and a normal lower extremity neurologic examination. Radiographs of the symptomatic region are normal. For the examining physician, what might be the differential diagnosis for this individual? What would the next step be in the physician’s evaluation process?
This clinical scenario is not uncommon. Certainly the variety of entities that can produce these symptoms is broad, but one should keep in mind that peripheral nerve entrapments frequently present in this manner. In this particular case, the patient was diagnosed with a saphenous nerve entrapment at the level of the knee where the saphenous nerve passes between the sartorius and gracilis tendons. The patient responded to temporary avoidance of aggravating activities, stretching of the relevant musculotendinous structures, and an ultrasound-guided saphenous nerve block with a combination of local anesthetic and corticosteroid at the site of entrapment.
In my opinion, there are a few key items that increase my suspicion that an athlete’s symptoms are being caused by a peripheral nerve entrapment.
a. Neuropathic symptoms (e.g., paresthesias, weakness) in the distribution of a peripheral nerve
b. Symptoms exacerbated by activity that are improved with rest
- Physical examination
a. Positive Tinel’s sign over the entrapment site (percussion elicits sensations of nerve irritation, e.g. ‘pins and needles’), which reproduces symptoms in the same distribution as the athlete’s pain
While electrodiagnostic studies and standard imaging studies are frequently normal in athletes with peripheral nerve entrapments, I have found ultrasound to be very helpful when evaluating this patient population. First, diagnostic ultrasound can frequently identify the location of nerve entrapment, which presents as focal compression of the nerve at the site of entrapment and enlargement of the nerve proximal to the site of entrapment. Second, if the diagnostic ultrasound examination is unrevealing, but nerve entrapment is still suspected, an ultrasound-guided diagnostic nerve block at the probable site of entrapment can be performed. If the athlete’s symptoms are resolved by the nerve block for the duration of the local anesthetic, this is highly suggestive that nerve entrapment is the source of the athlete’s pain. If not, then an alternative pain generator should be sought.
In our article, “
Lower Extremity Nerve Entrapments in Athletes
”, recently published in ACSM’s Current Sports Medicine Reports, the history, physical examination, diagnostic studies and treatment options for common lower extremity nerve entrapments in athletes are discussed. Hopefully, this information will add to the “tools in the physicians’ toolbox” and improve their ability to successfully identify and treat athletes with nerve entrapments.
Viewpoints presented on the ACSM blog reflect opinions of the authors and do not necessarily reflect positions or policies of ACSM.
Jonathan T. Finnoff, D.O., FACSM, is a senior associate consultant in the Department of Physical Medicine and Rehabilitation at Mayo Clinic School of Medicine, and a clinical professor in the Department of Physical Medicine and Rehabilitation at the University of California Davis School of Medicine. He is the medical director of the Mayo Clinic Sports Medicine Center in Minneapolis, Minn. and a faculty member for the University of California Davis School of Medicine and University of Nevada School of Medicine Sports Medicine fellowships. He specializes in non-operative sports medicine and diagnostic and interventional ultrasound.
This commentary presents Dr. Finnoff’s views on the topic related to a clinical article which he authored with a colleague and which was published in the September/October 2014 issue of ACSM’s Current Sports Medicine Reports (CSMR).