Good morning Dr. Grief, i had bilateral TKR done September 24th, 2013. during P.T. on the stationary bike, the Therapist grabbed my foot on the pedal and took me backwards. This forced flexion caused severe instant pain.That was November 4th,and now i have shocking pain,clicking, popping, and instability. 2 injections have done nothing. i feel like something is torn,and another surgery is coming.Thanks for your'e time