Following up on this!
I've had a really lousy time since around US Thanksgiving (end of November). My knee swelled up so much that I could barely bend it or even fully extend it. Plus there was some pain putting weight on it (and occasionally lots of pain), making walking difficult. I even couldn't do a lot of my physical therapy exercises. So that definitely took me out of the dojo, and I actually haven't been doing a whole lot since then, and my knee has significantly improved, although it's certainly not perfect. We also got all of the paperwork in order for the MRI and the insurance company approved it.
I did the MRI this past weekend and we went over the images today. No meniscus tear or injured ligaments, not that we were expecting any. As
@JR 137 suggested, there is some degraded cartilage on the underside of the kneecap. There was also some mild bursitis, which makes sense to me given that I had a bout of bursitis back in June. However, the big surprise was that I have arthritis in my knee. My x-rays showed the beginnings of bone spurs, but not really anything that should be affecting me yet. However, the MRI showed some significant degradation on the inner half of the knee. It's not worn down so that there's bone on bone contact, but it's apparently enough to cause inflammation and pain.
The doc was actually pretty thrilled with the results since there's no surgery required, but I almost feel like an injury would have been preferable since you can fix that. Arthritis is kind of forever. The next step recommended is an unloader brace to take off pressure from the inner knee when I'm active. Unfortunately, this is another game with the insurance company. The guy who is taking care of running the insurance authorization and doing the actual measurements and ordering warned me that my insurance company doesn't have a good record for this, and another grad student actually had a lot of trouble getting the insurance company to pay for their brace. But we'll see how it goes.
I'm continuing the CH alpha supplement. Not sure if it's helping or not. My knee certainly feels better than it did two months ago, but I also spent the past month doing zero karate and nothing that would irritate my knee. My sister recommended Ostarplex, as it significantly helped her arthritis. It's a bit cheaper than CH alpha, but I can't find a ton of information on it. She also has a very different type of arthritis (psoriatic). I'm hesitant to try both at the same time (how do you figure out which one works?), plus that's even more money spent each month. Guess I'll probably stick with the CH alpha for now since it's recommended by my doc. Although my mom decided to try the Ostarplex, too, so if she has good results, then maybe that's a good sign that it would be helpful for me. Speaking of Mom, this arthritis is a gift from her. Her knees deteriorated in the same way. Guess my hips are next, too.
The doc also suggested that I give up karate. Specifically, he said that stomping around during karate will irritate my knee, even with the brace on. I suppose he doesn't know a lot about karate - I wouldn't call it a stomping art. Although I am guilty of stomping around quite often, which my instructor continuously tells me not to do (and since having knee problems, has pointed out that it's going to cause more knee issues). It has been getting better over time. Anyone have any thoughts on that? There are a bunch of old guys in our organization who still train with arthritis and various joint replacements, but they've also been doing this for decades and probably aren't inclined to switch to something gentler on the joints. Should I really think about calling it quits and find an art that's a bit lower impact on the knees? There's not an incredible amount of different martial arts in my immediate area. Mostly Kenpo, Taekwondo, and BJJ. I doubt the Kenpo would be dramatically different in terms of impact level, Taekwondo is a no, but perhaps the BJJ would be kinder. There's also a Pukulan school, but I don't know much about that art. There's a Danzan Ryu place about 35 minutes away, but I'm not sure I really want to go that far, especially since traffic can easily increase that to 45 minutes or longer.