What is arthrofibrosis after knee surgery?

What happens in the knee

Every operation triggers healing, and some scar tissue is normal. In arthrofibrosis, the body overproduces it. Dense fibrous tissue can fill the pouch above the kneecap, tether the kneecap, thicken the fat pad, or form bands between the joint surfaces. The joint lining may stay inflamed, which keeps the knee warm, swollen and painful.

The result is a knee that will not move as far as it should, despite good effort in rehabilitation.

Different forms

• Localised scarring, such as a cyclops lesion: a nodule of scar in front of an ACL graft that blocks full straightening
• Kneecap tethering, where scarring around the kneecap or fat pad limits its glide
• Generalised arthrofibrosis, affecting the whole joint with loss of both bending and straightening
• Secondary stiffness from a specific cause, such as a graft or implant position, infection or pain that prevented movement

How it is diagnosed

Diagnosis is clinical: the surgeon measures straightening and bending, compares them with the other knee, and checks kneecap mobility and swelling. Loss of straightening matters most for walking, even a few degrees.

X-rays check the position of any graft or implant. An MRI can show localised scar tissue such as a cyclops lesion, and blood tests or joint fluid tests may be used if infection is a concern.

Treatment outline

Early treatment focuses on calming inflammation and restoring movement with targeted physiotherapy, sometimes with medicines or an injection. If movement stalls, a manipulation under anaesthesia or arthroscopic release of scar tissue may be advised.

At Aman Hospital in Doha, Dr. Gelber looks for any specific cause first, because correcting that is part of the treatment.