Note
Today was my long-anticipated appointment with the sports specialist to discuss my knee. I like this guy. He was willing and able to explain things using physics, after I mentioned that I'd done a Masters in biomechanics. He isn't over-serious. One of his first comments was that the reason I have so many knee problems is that I had an MRI. (I guess he subscribes to the "if a tree falls in the forest with no one there to hear it, then it made no sound" theory.)
He suggests that I ignore the torn meniscus unless it produces more serious symptoms, and then I would get the knee scoped. Although I've got a degenerative tear that can't be fixed (which I already knew), this type of tear is less likely to cause problems than the traumatic tears young basketball players get.
He believes there is hope to stop the kneecap pain by working to get it tracking correctly. He was happy to hear about my leg strength exercises, but advised against a couple of exercises that cause the kneecap to move laterally (to the outside of the leg), e.g. wide-stance squats. (The exercise routine was developed when it looked like I had ACL problems, so it's not surprising that it needs a tweak or two.) He also advised against doing leg extensions on the weight machine. Apparently my hip flexors aren't flexible, so I should do some stretches. When these muscles are tight, they torque the femur, which moves things out of alignment.
I asked the dreaded question about whether I should change my level of activity. First, he said that no study has made a strong correlation between running and arthritis in later life, even though this is generally assumed by physicians. On the other hand, since I already have degenerative changes, my odds go way up. What is not known is how much worse my odds will become if I keep running. It is possible that my future will unfold pretty much the same way regardless of what I do. He advised listening to my body and not doing things that hurt. (Hmmm... pain is the whole point of adventure racing!) Then he immediately told me that he ignores his own advice and participates in sports with a sore knee. Interestingly, he hasn't had an X-ray or MRI yet. He believes strongly that symptoms are the important thing to consider, not fancy tests.
So... lots to think about.