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Tuesday, March 11, 2014
Piriformis and knee pain
I will start by stating the I was in a car accident when I was 14 years old, had my first ankle(left)fusion at 18. It was not in the correct position and as a result walked with a pronounced limp and was in constant pain of my ankle. At the age of 38 in 2003, I had another fusion to correct the first and now am virtually pain free in the ankle area and my limp is extremely slight. Since February 2007 I have had a terrible pain that is in my right buttock, skips the back of my leg and starts on the outside of my right knee.My calf and middle toes tingle and have decreased sensation. I have tried ice packs, which do numb it, but it comes right back, heating pads, muscle relaxers, Diclofenac, advil, tylenol, and currently gabapenton. I was unable to get more than 4 hours of sleep at night, could not sit at my desk until taking tylenol and/or pain pills, and driving was difficult. The pain is worse with sitting, and will decrease with activity. I have had two MRI tests, one of the lumbar spine, showing slightly bulging discs and slightly decreased water level in L3 and 4, the other of my hips and pelvis. The impression -"a subchondral asymmetric water weight signal focus in the right acetabulum. This could represent a degenerative geode type focus". I have also had an EMG with normal results. I have been to two different chiropractors, the last one thinking adjustment was not the solution. He diagnosed me with piriformus syndrome. I also tried a therapist who would have me warm up on the eliptical, then stretch out my legs. I did this for two weeks but was not getting any better at all. I have been taking gabapenton for 2 weeks, and it does help, but the pain still breaks through and is worse after 4 or 5 hours of sleep. The doctor has suggested I double my dose at night (300 mg twice a day, so 600 mg at night) to see if this will get me through the night. The doctor now thinks I may have bursitis of the hip and an embedded nerve on my knee. I am scheduled to see an orthopaedic doctor in 2 weeks. I am curious as to your thoughts on my condition and if you have treated similar.
Your 20 or more years of limping have placed asymmetric stresses on your body; your symptoms may very well be the cumulative result from repetitive overload to the right side of your body, despite how much better you've been feeling and walking since the second ankle fusion. Potential causes for your symptoms include:
- nerve "irritation" (despite the normal EMG, which fortunately revealed no loss of nerve function), which would much more commonly involve nerve root fibers in the lumbar spine rather than sciatic nerve fibers within the piriformis muscle... also, the most common nerve problem at the knee which involves the peroneal nerve would not cause buttock pain nor knee pain nor calf tingling/numbness...;
- myofascial pain, which involves "soft tissues" - particularly muscle, including possibly the piriformis muscle... with myofascial pain, there would be one or more "trigger points" which, when pressed, would reproduce your pain and numbness symptoms... this would not show up on an MRI scan;
- sacroiliac joint pain, which not infrequently causes pain to "refer" down the leg... this would not show up on an MRI scan;
- bursitis involving the hip, usually the outer part (called trochanteric bursitis), which also not infrequently causes pain which refers down the leg... this doesn't always show up on an MRI scan; and...
- hip joint pain, which could either arise from the surfaces of the hip (ball-and-socket) joint or, alternatively, from the cartilage lip (or "rim") around the perimeter of the hip socket (called the acetabular labrum) which could possibly have a degenerative tear... these potential causes don't always show up on an MRI scan.
Your physical exam findings should help sort out whether one or more of the above is contributing to your symptoms, but since you're still without a diagnosis, and since MRI scans often don't reveal the source of a person's pain, selective injections (using an anesthetic such as Lidocaine to temporarily dull or eliminate pain, combined with a steroid to reduce inflammation) of one or more of the above may be useful and necessary to clarify your diagnosis and at the same time treat your symptoms.
Brian L Bowyer, MD
Clinical Associate Professor
Physical Medicine & Rehabilitation
College of Medicine
The Ohio State University