Arthrofibrosis involves formation of excessive scar tissue in a joint. It can affect any joint.
Arthrofibrosis of the knee can occur after soft tissue injuries or fractures in and around the knee, arthroscopic knee surgeries like anterior cruciate ligament reconstruction or meniscal surgery, open knee surgeries and knee replacement. The incidence of arthrofibrosis after knee replacement is 1.2% to 17%. This section gives information about arthrofibrosis following knee replacement.
Causes and Development of Arthrofibrosis after Knee Replacement
The exact cause of arthrofibrosis following knee replacement remains unknown. Many factors like genetic predisposition, immune response and allergic reaction have been proposed as potential risk factors but none has been proven.
The molecular steps and mediators involved in the development of arthrofibrosis are unclear. There is chronic inflammation in the soft tissues in and around the knee. This leads to the formation of excessive amount of scar tissue, sometimes even cartilage or bone, in the soft tissues.
Symptoms and Signs of Arthrofibrosis after Knee Replacement
The characteristic symptoms of arthrofibrosis of the knee following knee replacement are stiffness and chronic pain in the knee. The patient may not be able to bring the knee fully straight (flexion contracture) or there is decreased ability to bend the knee fully (decreased range of flexion). Many patients have both. The stiffness varies in severity. The knee is swollen, red, warm and painful to touch (tenderness). The soft tissues around the knee feel firm. Patients may have quadriceps weakness. Patients may also have leg length discrepancy and altered gait. Arthrofibrosis affects the patient’s professional and personal life.
Diagnosis is mainly based on the characteristic symptoms and signs. After knee replacement, the range of motion of the knee progressively improves and the pain progressively decreases over two to three weeks. Arthrofibrosis is suspected if the motion does not progressively improve, remains stable or decreases after knee replacement. Arthrofibrosis is also suspected if the pain does not progressively decrease, persists without any change or increases after knee replacement.
Plain radiographs may show bone formation in soft tissue.
Treatment of Arthrofibrosis after Knee Replacement