Last reviewed: September 29, 2026

Most of the bend comes back early. In one study, nearly all of it had returned by six weeks on average. Smaller gains can continue for up to a year.

How far your knee bends after surgery depends a lot on how far it bent before. In a large study, the bend before surgery was the strongest predictor of the bend after. A knee that was stiff going in often ends up bending less.

Research often calls a knee stiff when it bends less than about 90 degrees three months after surgery. That is not a strict line, because it depends on where the knee started. For comparison, one study of healthy older adults found that stairs and getting up from a chair take roughly 90 to 120 degrees.

If the knee stays stiff despite therapy, your doctor should look for a cause. The usual next step is a manipulation: the surgeon bends the knee while you are under anesthesia. It is best done within the first three months.

Knees that still feel stiff a year after surgery are linked to worse function and less satisfaction.

In general:

  • Most of the bend comes back in the first six weeks.
  • How far it bends depends partly on how far it bent before surgery.
  • If you are falling behind, tell your surgeon early rather than waiting.
  • If a manipulation is needed, it is best done within the first three months.

Drafted with AI assistance from published sources, reviewed and edited by Babak Sheikh, MD.

Sources:

This is general information about what published research shows. It is not medical advice and it is not about your situation. Reading it does not create a doctor-patient relationship with me. I am a retired orthopedic surgeon and I do not see patients. Talk with your own doctor before changing anything about your care. If something feels suddenly or seriously wrong, get medical care promptly rather than waiting.

This page is provided as is. I make no guarantee that it is accurate, complete or current, and medical evidence changes. Use of it is at your own risk.

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