(HealthDay News) -- Knee replacement surgery may be a solution for disabling arthritis, pain caused by other medical problems, or a tumor affecting the knee.

But if you've got certain risk factors, your doctor may advise against the surgery, the U.S. National Library of Medicine says. Here are some examples:

  • Having an infection affecting the knee.
  • Being morbidly obese.
  • Having very weak muscles at the front of the thigh, making it difficult to walk.
  • Being severely mentally impaired.
  • Having insufficient blood flow to the leg, which could prevent proper healing.
  • Having terminal cancer that continues to spread.