Here is a strange one. Got up one morning. Took a few steps. Left knee wobbly. Moved(flexion) back and forth fully as if the ligaments were all disconnected. No pain. No damage as far as I know. Doctors baffled. When I walk the knee joint moves forward and backward fully rather than locking as one strides leg by leg. Any ideas. I am getting a brace for now but nobody knows the problem.