I have been running on a treadmill for the past few months. Recently, I have experienced my right knee stiffen and almost lock while running. It causes me to stumble a little, but I'm able to keep my pace. Afterwards, my calves and ankle are sore. I've been able to run 5+ miles on the treadmill before, but now I'm struggling to conistantly get to 4 or 5. I had surgery on that knee for a dislocation in 1999 and then had a lateral release in 2006. Is there anything I can do to help me be able to run on a treadmill?
Not sure why it is happening but I'd incorporate stretches and strength training (especially quads/gluts/hamstrings) to keep your knee strong. Too many things can throw off our knee. I had hip aches and doing Yoga specific stretches made a huge difference...and I am not the YOGA type (if there is one). I just found that the stretching was VERY beneficial.
Since's it is only in one knee it sounds like a physical problem. Besides the advice above, think about cross training. My experience has been that cycling/spinning at high cadence really stablizes the knees, seems to encourage me to run faster and smoother. Aggressive hiking seems to give my hips and gluts a killer work-out.