Total Knee Replacement (TKR) is a significant operation but one of the most common orthopaedic procedures, with over 70,000 operations performed each year and this number is rising. Many people require this type of surgery and thankfully it has a very high rate of success. The most common cause of damage to your knee is arthritis. One in particular – osteoarthritis (known as wear and tear arthritis) can set in over time and cause pain and stiffness.
What is Osteoarthritis?
There are 2 common types of cartilage in the knee surgeons refer to: The first type is the MENISCUS – 2 cartilage cushions or ‘menisci’ between the thigh bone (femur) and the shin bone (tibia). The menisci help the knee to function properly by bearing load and weight, absorbing shock, stabilising the joint and providing lubrication. The second type is ARTICULAR CARTILAGE which covers the surface bone ends of the femur, tibia and patella (knee cap) to reduce friction and cushion the joint to aid load distribution. Osteoarthritis, or degenerative joint disease, is the most common type of arthritis often due to ‘wear and tear’ or damage of this smooth articular cartilage surface which becomes irregular, fissured and may fall off revealing the underlying bone. If this happens, the underlying bones can rub together, producing the pain typical of arthritis. It causes pain in the joints and surrounding soft tissues and limits the range of movement and function of a joint.
There are several factors which contribute to the development of osteoarthritis, including age, being overweight, heavy manual jobs, genetic factors, and joint damage from a previous injury. Severe arthritis can interfere with activities of daily living and limits lifestyle. The severe pain of osteoarthritis can be very disabling.
What are the treatment options?
There is no cure for arthritis, so beware of ‘miracle cures’. The first step is to preserve the knee and avoid surgery if possible. Initial treatment of osteoarthritis focuses on decreasing pain and improving joint movement with a balance of rest and exercise, avoiding vigorous weight bearing activities. Patients are given individualised treatment plans which may consist of:
- Education and understanding.
- Exercises to keep joints flexible and improve muscle strength.
- Joint protection, to prevent stress or strain on painful joints e.g. knee supports or braces, cushioned insoles, and orthotics.
- Medicines: e.g. anti-inflammatory gels, the use of non- steroidal anti-inflammatory tablets (e.g.neurofen or naprosyn), non-narcotic analgesics such as Paracetamol. Alternative medicines such as Glucosamine and Chondroitin and cod liver oil.
- Physiotherapy and/or heat or cold treatments.
- Weight control to prevent extra stress on weight bearing joints.
- Injections of Hyaluronic acid or Steroids into the joint. Steroids improve symptoms by reducing the inflammation within the arthritic joint. Hyaluronic acid preparations are available which can be injected into joints affected by osteoarthritis to relieve pain, restore lubrication and cushioning, improving joint function.
What about Surgery?
Simple arthroscopic or key-hole surgery may be appropriate if there are mechanical problems within your knee joint such as catching, locking, swelling or giving way. Correcting the mechanical damage may prevent further deterioration of your knee. In some cases surgery will not be able to reverse the damage which has already occurred. In severe cases, surgery may be suggested, such as knee replacement which can give good results.
The type of surgery will depend on your age and severity of the disease. The knee joint is made up of 3 compartments, the patellofemoral (kneecap) and medial (inside) and lateral (outside) compartments between the femur and tibia (ie: the long bones of the leg). Often only one of these compartments wears out, usually the medial one. If you have symptoms and X-ray findings suggestive of this then you may be suitable for a Unicompartmental or Partial Knee Replacement procedure where only the damaged part of the knee joint is replaced through a smaller incision (minimally invasive surgery) than would normally be used for a Total Knee Replacement.
The aim is to keep the patient mobile and active with more rapid rehabilitation and greater activity at an earlier stage following an operation. A Total Knee Replacement (TKR) is an operation where the arthritic knee joint is resurfaced with artificial metal surfaces (cobalt chrome or titanium) secured with bone cement and a plastic insert cushion between these metal surfaces. Sometimes the surface of the Patella (kneecap) is worn and if it is badly damaged this is resurfaced (with plastic) as well. The surgery starts with an incision over the knee which exposes the joint. Special guides and precision instruments are used to remove the damaged surfaces and create the fit for the implants. The implant is then secured to the bone(s). It may be necessary to re-align the surrounding knee ligaments to achieve the best knee function. Once the components are fixed in place and the knee is balanced and stable, the incision will be closed.
You are likely to benefit from TKR if your pain is severe and interferes with day-to-day activities. This includes severe knee pain and stiffness that limits mobility and function or severe pain that disturbs your sleep. 80-90% of individuals who undergo Total Knee Replacement experience a dramatic reduction of knee pain and a significant improvement in movement and the ability to perform the common activities of everyday life. Many patients get back to exercise (swimming and dancing) and sports such as golf, cycling and social tennis. Your range of movement, muscle strength and pain should continue to improve during the first year after surgery.
