Knee replacement surgery, also known as arthroplasty, is an operation to replace a diseased, worn or damaged knee joint with an artificial replacement. It is a routine surgery and can be performed on adult patients of any age, although is most commonly carried out between the ages of 60 and 80. Patients of a younger age are increasingly being offered this operation.
Several factors increase the risk of knee problems. Excess weight puts added pressure on the knee joints, even during ordinary, everyday activities such as walking up stairs. Being overweight or obese also increases the risk of osteoarthritis, an additional risk factor. A lack of muscle strength and flexibility can increase the risk of knee injury, as strong muscles help to stabilise the joints. However, it is important to be smart about exercise; warm up techniques, choosing the right exercise and considering old injuries can minimise the risk of knee damage.
Arthroplasty is usually necessary if the knee joint has become damaged to the extent that it effects movement and quality of life. If a patient experiences pain even when resting, doctors may recommend the operation. Replacing the knee joint is major surgery, so other options such as steroid injections and physiotherapy will usually be explored before an operation is advised.
Depending on the extent of damage to the knee, there are various replacement options available to patients. The type of replacement mainly refers to the amount of the knee which is replaced. In terms of functionality, a partial knee replacement which involves just one component is preferable; it is less invasive and more likely to feel like a ‘normal’ knee afterwards. This surgery replaces only the damaged part of the knee and preserves its biomechanics and healthy ligaments.
Unfortunately, not everyone who requires knee replacement surgery will be eligible for a partial replacement. It is only suitable when the damage is confined to one part of the knee, if the ligaments are intact and bone quality is good. A total knee replacement is necessary if both sides of the knee are affected and need to be replaced.
Other knee replacement surgery options to consider include 3D printing and the use of robotics in surgery. A 3D printed knee aims to create a bespoke knee joint for each individual patient; the theory behind this individualised approach is that different people have different sized knees. As part of preoperative planning, a 3D scan is taken of the knee and the joint is then printed. Although doctors hope that this type of replacement joint will last longer, with fewer complications, there is currently insufficient research to suggest it is any more efficient than standard knee replacement surgery.
Robot-assisted surgery is another option to consider and is available at a number of UK medical institutions, including clinics where Professor Ali Ghoz consults and practices such as The London Clinic, BUPA Cromwell Hospital and Chelsea Bridge Clinic. Surgeons are specifically trained to use the robot; it is shown through X-rays that they have a better alignment with their implants using this technology. Early evidence suggests that patients experience less post-operative pain than non-assisted surgery and can expect a faster discharge from hospital. As with 3D printing, there is not yet enough data to gauge effects on long-term patient prognosis.
After surgery, patients usually remain in hospital for 3-5 days, although this depends on the type of surgery and individual circumstances. Most physical activities can be resumed within 8-12 weeks, but full recovery can take up to 2 years as the muscles strengthen and scar tissue heals. 95% of knee replacement surgeries last between 10 and 13 years.