Knee pain for year | bursitis by ultrasound | why I don’t think local pain | acupuncture

This is a case I treated yesterday — a patient with one year of lateral knee pain. Ultrasound showed bursitis, but I suspected the pain wasn’t simply due to that.

Further examination revealed:

• Dull sensation on the upper lateral calf;

• Tapping over the lateral groove of the popliteal fossa reproduced radiating pain to the upper lateral leg;

• Palpation at the same groove also triggered similar radiation.

The diagnosis was lateral sural cutaneous nerve entrapment, with the compression site located at the lateral popliteal groove. After acupuncture treatment, the radiating pain resolved significantly. I’ll follow up on the long-term outcome at the next visit.

My opinion

1, The knee pain is located on the lateral side of the left knee and sometimes radiates to the upper lateral aspect of the left lower leg.

2, There is a dull or numb area on the upper lateral side of the left lower leg.

3, Tinel’s sign: when tapping on the lower posterior thigh, the pain radiates to the upper lateral part of the left lower leg.

4, If the entrapment is located at the point where the lateral sural cutaneous nerve branches off from the common peroneal nerve, both nerves could be involved, potentially resulting in foot weakness. However, if the entrapment is below that point—after the lateral sural cutaneous nerve has already branched off—only the common peroneal nerve would be affected, and there would be no sensory disturbance in the upper lateral lower leg.

5, Since there is no weakness in the left lower leg, this is a case of pure lateral sural cutaneous nerve entrapment. The entrapment site is in the lateral groove of the popliteal fossa.

6, Acupuncture at this groove can release the entrapment, and the pain disappears.

7, Why didn’t I initially consider a local knee problem? First, because the pain sometimes radiates to the upper lateral part of the left lower leg. Second, the patient wakes up at night due to knee pain. Third, there is no tenderness on local palpation. These points prompted me to perform further examinations, including sensory testing and Tinel’s sign.

8, I decided to do further examination—especially neurological tests—because something didn’t quite add up. Once I show you what I did, the diagnosis becomes very clear, and honestly, it doesn’t seem impressive at all. But recognizing the need for those extra steps—that’s the part I think is worth sharing.

I helped cases before.

1), https://youtu.be/ZMnbhUWjhpw

2), https://youtu.be/2csg4dPsIEE