Arthrofibrosis of the knee can be caused by previous injury or surgery of the knee. Scar tissue is formed inside the joint which causes shrinkage and tightening of the knee joint’s capsule. The knee joint stiffens up and the range of motion is decreased. If aggressive stretching and exercises in physical therapy do not help the knee can be manipulated under anesthesia in order to tear the internal scar tissue. Ultimately an arthroscopic removal of the internal scarring can be performed.