Ankylosis is the immobilization and stiffness of a joint. In this case, ankylosis refers to the knee, which is the anterior part of the leg formed by the femur, tibia, and patella.

Ankylosis may be congenital. Additional causes include: surgery; trauma; diseases of the bone or joint; infection; certain tumor-like conditions affecting the joint linings (osteochondromatosis and pigmented villonodular synovitis); or contractures due to immobility.

With this condition, there may be restricted range of motion; immobilization and stiffness. (Normal range of knee flexion and knee extension is approximately 140°) Other signs and symptoms may arise from joint disease, such as arthritis; pain or tenderness; swelling; deformity; and crepitus.

Laboratory tests will be based on the underlying disease or condition. X-rays, computed tomography (CT) scan, and magnetic resonance imaging (MRI) are used in the diagnosis. A goniometer is used to measure ranges of extension and flexion angles of joints.

General treatment for ankylosis may include physical therapy and maintenance of the joint in a functional position by range of motion exercises to the affected joints. If the ankylosis was surgically created, the joint is kept immobilized in correct body alignment for 6 to 12 weeks until the bone is healed. Medications and other therapies may be instituted to treat other conditions that contribute to the condition such as arthritis.

Atrophy at the site of the joint may occur due to decreased activity. The possibility of long-term physical therapy exists.

• The rating schedule for musculoskeletal was updated on February 7, 2021. Protection still does apply and should be considered with existing evaluations (38 CFR 3.951(a)).

• May be entitled to special monthly compensation where the Veteran has extremely unfavorable knee ankylosis will constitute loss of use of the foot. Loss of use of a foot will be held to exist when no effective function remains other than that which would be equally well served by an amputation stump at the site of election below elbow or knee with use of a suitable prosthetic appliance. The determination will be made on the basis of the actual remaining function, whether the acts of balance, propulsion, etc., in the case of the foot, could be accomplished equally well by an amputation stump with prosthesis. 38 CFR 3.350(a)(2)(i)(a)

• None.