Knee replacement can bring huge increases in life quality and if measured by "quality life years", knee replacement, hip replacement and cataract surgery are the most successful procedures performed in modern medicine. Approximately 70,000 knee replacements are performed each year in the UK and this number is rising. There is evidence that generally in the UK, surgery is performed much later in the disease process than in other countries and perhaps better results could be obtained with earlier intervention. 

The term total knee replacement or TKR, is actually a misnoma as the vast majority of knee "replacements" are actually resurfacings. The worn portions of the joint are removed and replaced by metal and plastic bearings.

Most of the ligaments and tendons around the joint are still required and the major part of the surgical skill is to adjust all the cuts to give the ideal tension in these structures while correcting the alignment of the limb and get a good range of movement.

While it is not usually possible to give you a knee like the one God made, a good, modern knee replacement should be pain free with an almost normal range of movement and allow light to moderate exercise. (Walking as far as you like, cycling, social tennis, social skiing, if you are good!).  Unfortunately, running and jogging are not advised.

The knee replacement should last for about 15- 20 years on average, although some will fail earlier especially if abused.

Revision (re-doing) of the knee replacement is usually possible several times, but each attempt gets harder with increased risks.