The purpose of any joint replacement is to remove the arthritic ends of the long bones, which cause patients so much pain and dysfunction, and realign the biomechanical axis of the joint. When the cartilage of a knee wears down the patient's leg often becomes profoundly bow legged or knock kneed. Replacement makes the leg straight again.
In addition to x-ray evidence of cartilage loss and joint deformity, a patient is ready for knee replacement when they can't take the pain another day and when they want to get their life back.
Knee replacement is major surgery requiring 2-4 days of hospitalization post-op and about 3 months of out patient rehab afterwards. Following replacement we encourage patients to return to as much activity as possible. I let my patients with total knees to anything except long distance running and there are many athletes in the senior olympic games with total joints