Knee pain can be the result of a wide variety of underlying causes. One such cause of knee pain that is often overlooked as even a possibility is entrapment of the saphenous nerve. The saphenous nerve is the largest sensory nerve in the human body, branching from the femoral nerve up the leg into the adductor canal in the hip. Nerve entrapment can happen when the nerve pierces membranes inside the leg or when the nerve is sheered at some point. Some activities are known for stretching or rubbing the nerve, and the repeated friction can result in nerve entrapment.
Marathon running is one such activity that can cause nerve entrapment. Many runners experience muscle fatigue or excessive tightness in their hip rotators, as well as tension of the saphenous nerve through the adductor canal.
Typically, nerve entrapment like this means surgery or injections for the patient’s knee pain. In the interest of testing a more conservative, less-invasive approach, a recent case study highlighted the efficacy of manual therapy and exercise rehabilitation on nerve entrapment.
The patient was a 29-year-old female runner who competed in ultra-marathons and suffered from constant, nonspecific knee pain. She rated her pain as a 6 on a 10-point pain scale. Unfortunately, she reported that running exacerbated her knee pain. An examination revealed that the woman had hip external rotator fatigue and pelvic instability. Ultimately, she was diagnosed with saphenous nerve entrapment.
A doctor of chiropractic utilized a conservative treatment called the Active Release Technique (ART). This process is done by actively placing tension on the surrounding tissues and the membrane that is pierced by the nerve. The hope is that this manual therapy on the soft tissues will release the nerve from its entrapment.
During the first ART session, a release was felt and even heard, followed by a brief increase in the patient’s pain. However, the pain almost immediately decreased, and she rated her pain a 2 out of 10 after this treatment session. The effect lasted a week until her next ART session. Again, she felt a release, and this time she reported the pain was fully resolved. The woman was able to return to her ultra-marathon training.
The second part of the treatment plan in this case study involved at-home exercise rehabilitation. The patient was instructed and followed through with exercises involving squats with both legs in front of an exercise ball against a wall, standing on one leg with the hip holding an exercise ball against a wall, and squats from a variety of angles on just the left leg, which is where the knee pain was located.
The patient continued using these rehabilitative exercises periodically as needed, and at her 16-month follow-up she continued to be free of knee symptoms.
Although this study was limited to a single patient, it was the first of its kind to investigate a noninvasive approach to saphenous nerve entrapment, and its success is good news for knee pain patients with this diagnosis who desire conservative management of the condition.
Other causes of knee pain have been shown by previous research to respond well to conservative treatment options, such as trigger point therapy, exercise, and a form of acupressure called collateral meridian therapy.
Settergren R. Conservative management of a saphenous nerve entrapment in a female ultra-marathon runner. Journal of Bodywork & Movement Therapies 2013; 17: 297-301.