What is arthrofibrosis?

Arthrofibrosis is also known as stiff knee syndrome. The condition sometimes occurs in a knee joint that has recently been injured. It can also occur after surgery on the knee, such as a knee replacement. Over time, scar tissue builds up inside the knee, causing the knee joint to shrink and tighten.

Scar tissue from arthrofibrosis can severely impact your knee’s range of motion. In the most severe instances, it can result in a permanent inability to bend and straighten the knee.

The incidence of arthrofibrosis is extremely low. Some knee stiffness following a total knee replacement is normal. Slight stiffness may persist for months or years and become more apparent after exercise or activity. However, if arthrofibrosis occurs, certain symptoms are common:

Flexed knee gait

Your gait is the cadence and form by which you walk. It can indicate the health of your knee alignment and motion. Walking with a bent knee can be a sign of stiffness and may indicate that you’re developing arthrofibrosis.

Worsening pain in the knee

Normally, pain steadily decreases after surgery. If you experience an increased amount of pain, talk to your doctor. This could be the result of arthrofibrosis, especially when it occurs along with reduced flexibility.

Ongoing swelling

Arthrofibrosis causes swelling in the soft tissue around your knee. This is different than swelling due to fluid buildup. Your doctor can determine the cause of the swelling and treat it.

Weak quadriceps

If you’re unable to contract your quadriceps muscle in the front of your leg or have other issues moving your leg, ask your doctor to check your knee for arthrofibrosis.

Hotness around the knee

It’s normal after surgery to feel that your knee is warm or hot. However, contact your doctor if a feeling of warmth remains after two or three weeks.

The likelihood of developing arthrofibrosis increases with the severity of the trauma to the knee joint or the length of a surgery. The longer your knee is immobile, the greater your risk of having the condition. This is why it’s important to keep moving the knee.

If your surgeon gives you a diagnosis of arthrofibrosis, you’ll require additional treatment or possibly surgery:


In some cases, the surgeon will manipulate the knee to break up scar tissue while you’re under sedation or anesthesia.

Arthroscopic surgery

A growing number of surgeons are now turning to minimally invasive arthroscopic surgery to remove the scar tissue. This process is called arthrolysis.

Open surgery

In the most severe cases, more aggressive surgery may be necessary. After treatment or surgery, you’ll need physical therapy.

After the initial treatment for arthrofibrosis is complete, numerous rehabilitation activities are available. They’re designed to maintain motion and prevent a recurrence of the condition. These include:

  • use of a continuous passive motion (CPM) machine
  • exercise, such as walking on a treadmill, cycling, and immersion in water
  • bracing

Although it’s a rare condition, it’s important to be on alert for arthrofibrosis. Those who have it are likely to have difficulty recovering and returning to a more active lifestyle. Monitor your range of motion throughout your recovery and talk to your doctor if you notice stiffness or any decline in the function of your artificial joint.

Your surgeon may prescribe a CPM machine while you’re lying in bed and recovering from surgery. Your surgeon or physical therapist may also provide exercises designed to reduce the risk of developing arthrofibrosis. Using the following may reduce the odds of experiencing arthrofibrosis:

  • a compression dressing
  • cryotherapy, or the application of extreme cold
  • a suction drain