Arthrofibrosis is a complication of knee injury or surgery where an excessive scar tissue response leads to painful restriction of knee motion, with scar tissue forming within the joint and soft tissue spaces and persisting despite routine rehabilitation exercises and stretches. The term may involve flexion loss, extension loss or both.
The consequent pain may lead to the cascade of quadriceps weakness, patellar tendon adaptive shortening and scarring in the tissues around the patella - with an end stage of permanent patella infera - where the patella is pulled down into an abnormal position where it becomes vulnerable to joint surface damage. In severe cases of arthrofibrosis the disorder becomes progressive and the whole capsule may become thickened and tight with almost no movement possible in the joint.
Despite this potentially disastrous cascade of events, patients with developing arthrofibrosis and early patella infera may avoid the necessity for surgical intervention by participating in a closely supervised therapy programme. The key is early recognition and referral to a unit experienced in dealing with arthrofibrosis.