knee problem

[Wynton]

I'm experiencing a new knee issue that appears minor, but I'm not sure.

In the past few weeks, I've been putting more stress on my knees by exercising a bit harder. And in the last few days, I get an occasional sharp pain, but I'm able to continue playing tennis or whatever 95% of the time.

I notice that the pain seems prone to occur when I stand up also and take the very first step. But then it disappears.

The pain is not so strong to suggest to me anything serious. But it's not going away either, which makes me a little concerned. When I experience this, I feel the knee buckle somewhat. It's also slightly tender in the middle of the kneecap, but just slightly.

If it keeps up, naturally I'll be headed to the doctor. But I'm just curious if this vague description sounds vaguely familiar to anyone here.