I had total knee replacement 12 weeks ago. yesterday i started experiencing a sharp 1 second pain in my upper thigh. very sharp and make my leg twitc?

Nerve pain: This may be an irritable or pinched superficial nerve as the pains are sharp and fleeting and there is also some twitching. It may or may not be related to your fairly recent hip surgery, physical therapy or stress on muscle or nerve fibers. I suspect that the symptoms will resolve on their own. If they persist or worsen see your orthopedic surgeon or a neurologist for evaluation and advice.