Saturday, September 1, 2012

Knee Pain from Cycling

Background
Early in January 2012 I had a very painful knee injury, caused by too much low-cadence cycling in too hard of a gear (see Singlespeed and Knee Pain). So when I felt more pain in both my knees again, eight months later, I was worried.

The pain was different - this time it was a more bearable, dull, widely-spread ache. Almost like a mild headache, just in the knee. However, it was persistent, and not only when pedaling too hard like before. In fact it even hurt off the bike.

At about km 80 of a 128km ride last weekend, I suddenly noticed a [painless] clicking sensation in my right knee, and then later at home the same in the left, albeit less pronounced.

I decided to visit a doctor and have it looked at. What I was really concerned about was whether or not I'd be doing long term damage (and how to prevent this while still cycling), and whether or not I could still participate in the upcoming 8-hour endurance MTB race just a week away.

Diagnosis
I asked my friendly neighborhood GP who I should speak to - a sports doctor, a physiotherapist, a cycling expert, who? He said in a case like this it's best to start at the top and let him refer you to a specialist. So he told me to see an orthopedist, and suggested a good one.

The next morning I called him, and was happily surprised to be able to schedule an appointment with him that morning.

I explained to him my previous injury, and my cycling habits and when, how and what the pain is all about. He performed these few simple tests on me:


  1. He pushed on the patellar tendon, directly below the kneecap, pressing up against the kneecap, almost under it. It hurt, suggesting damage to that tendon.
  2. He put my foot on his knee and asked me if I could touch my toes. I couldn't even reach my ankles. This indicates a tightness in the hamstrings. The hamstrings bend the knee, and have tendons that connect to the knee.
  3. He checked the lateral movement and pressed on the inside and outside and determined that the lateral ligaments were fine.


In short, my tight hamstrings are pulling the patella (kneecap) firmly - too firmly - against the femur and articular cartilage, creating unnecessary abrasion. This cartilage is supposed to be as smooth as glass, he said, and the scraping has roughened it up, making it bumpy, hence the clicks.

To me it's amazing to think tight hamstrings could be the cause of knee pain. But when you think about it, it's obvious, and just mechanics.

The pain comes from the patella rubbing against the articular cartilage too much, due to tight hamstrings.
Image source: Wikipedia


Solution

  1. The first, and most obvious thing I need to do is stretch my hamstrings. A lot.
  2. Next, I need to raise my saddle to keep the leg from having to be too bent too much. Think about it. The more my leg is bent, the more the patella will rub against the cartilage. When straight, the rubbing is minimized.
  3. Last, he prescribed me some [expensive] glucosamine sulphate which will help repair the cartilage; 1,500mg a day.
I asked him if I should be taking chondroitin - as a few of my friends suggested on Facebook. He said that once you take chondroitin it is simply converted to glucosamine in your body. He said chondroitin is just good marketing.


My Riding Future
This is the thing I was most worried about. He told me to continue putting the same mileage in, no problem. Just stretch and take the medicine. He said if I can handle the pain it's OK (though not really good) and I could still do the 8-hour race next weekend.