I have still not yet sorted out my right hip issues references in an earlier post, but apparently my  left knee is feeling left out, and has decided to join the party.

This is baffling me, and perhaps someone here knows if this is RA-related.

There is nothing wrong with my knee, in terms of its being able to bear weight, bend, etc.  I have no history of knee pain.  The hip pain to which I refered earlier does not affect my gait.  My activity level has not changed in the last few weeks.  I have not begun to wear new or different shoes, and the shoes I do wear have good support and are in good shape.

But yesterday I began to have sudden extremely sharp pains in my left knee that feel like a muscle cramp in terms of the rapid onset and severity.  Some happened when I was moving, and others when I was resting.  I can be sitting, standing, or lying down when it occurs. In fact, this nonsense woke me up overnight several times, which is particularly nasty (I'm not a good sleeper in general.)  I didn't check a clock during the nightm, but I'm guessing that I'm experiencing this once every two hours or so.  The frequenty has not changed since this started.

Each 'cramp' lasts a few agonizing seconds.  I can sense when it's coming because it starts and builds over about three seconds, holds for a few more, and then seems to go away.  I can't tell, yet, if the changing-of-position I immediatly do alleviates it, or if it would just last the same amount of time no matter what.  There is no residual pain afterward.  There is no tender spot.  The cramping feeling seems to be on the front of my knee, slightly to the inside of my leg.  The intensity of the pain is such that I'm a bit concerned about this happening when I'm walking or going down stairs, or driving.

There is no pain when I ascend or descend stairs, or if I squat, or any other connection that I can find to any movement on my part.

I consulted Doctor Google and noticed that RA came up as a possible cause, but the descriptions sound more like the RA-related knee pain is a constant ache, or that is corresponds to a tender spot.  Same thing with osteoarthritis, which I could certainly have in my knee at my age - but it's described as a dull ache.  That's very different than what I'm experiencing.  This is - I'm not kidding - like having a labor contraction at about 6 cm dilation.

It's nearly two months until my next appointment with the rheumatologist.  My Stelara shot was only four weeks ago, and usually I don't have any particular aches and pains until it's wearing off, in the last week or so before the next one.  If this keeps up I'll consult my GP and based on his advice I'll call the rheumatologist, but in the meantime, I'd like to learn more about how this wretched disease approaches one's kneecaps, or if you think this is something unrelated.