Good knees are an essential part of a healthy and active lifestyle. If your knee is severely damaged by arthritis or injury, it may be hard for you to perform simple activities, such as walking or climbing stairs. You may even begin to feel pain while you are sitting or lying down. However, when injury or arthritis occurs, particularly osteoarthritis, your ability to bend and flex your knees can become restricted due to damage, inflammation and pain. Over time, the damage progresses and life becomes more difficult and painful. If nonsurgical treatments like medications and using walking supports are no longer helpful, you may want to consider total knee replacement surgery. Joint replacement surgery is a safe and effective procedure to relieve pain, correct leg deformity, and help you resume normal activities.
ANATOMY OF A KNEE JOINT
Understanding knee joint anatomy would help us to know what can go wrong with the knee. Knee pain is a common problem that affects people at all ages. So many things can go wrong with the knee, and if we understand how everything work’s, we can make sure we do the right things to ensure a full recovery, prevent injuries and stop problems from coming back.
The knee is a joint formed, stabilized and given mobility by the articulation of bones, ligaments and tendons. This joint is the largest joint in the body and is formed by the articulation of the femur bone in the thigh with the tibia in the lower leg. The knee consists of three bones:
- Femur – the upper leg bone, or thigh bone
- Tibia – the bone at the front of the lower leg, or shin bone
- Patella – the thick, triangular bone that sits over the other bones at the front of the knee, or kneecap
The ends of the bones are covered with a layer of cartilage, a slick, elastic material that absorbs shock and allows the bones to glide easily against one another as they move.
The bones are held together by a joint capsule, which consists of two distinct layers – an outer layer of dense connective tissue and an inner membrane, called the synovium, which secretes a fluid to lubricate the joint, reducing friction to nearly zero in a healthy knee. Normally, all of these components work in harmony. But disease or injury can disrupt this harmony, resulting in pain, muscle weakness, and reduced function.
WHEN TO HAVE KNEE REPLACEMENT SURGERY
The most common reason to have a knee joint replaced is to relieve severe arthritis pain. One of the main reasons to consider knee replacement is pain that markedly limits everyday activities despite the use of anti-inflammatory medicines. For surgery to be considered, the pain should be disruptive to the activities of daily living, especially if it’s to the point that the person stays in the house more to avoid activity altogether. Many patients have trouble sleeping at night because of the pain caused by knee arthritis. Failure of anti-inflammatory medications to allow patients to sleep is another indication that it might be time to consider knee replacement.
IS TOTAL KNEE REPLACEMENT FOR YOU?
This is the most common form. The surgeon replaces the surfaces of the thigh bone and shin bone that connects to the knee. The decision to have total knee replacement surgery should be a well thought decision between you, your family, your family physician, and your orthopaedic surgeon. Alternatives to traditional total knee replacement surgery that your orthopaedic surgeon may discuss with you include a unicompartmental knee replacement or a minimally invasive knee replacement.
UNI COMPARTMENTAL KNEE REPLACEMENT
In unicompartmental knee replacement (also called “partial” knee replacement) only a portion of the knee is resurfaced. This procedure is an alternative to total knee replacement for patients whose disease is limited to just one area of the knee. Because a partial knee replacement is done through a smaller incision, patients usually spend less time in the hospital and return to normal activities sooner than total knee replacement patients. Partial knee replacement isn’t suitable for everyone because you need to have strong, healthy ligaments within your knee. Even though the operation involves less interference with the knee it is often a more complex operation than total knee replacement. It is therefore reccommended that patient opt for a total knee replacement. Unicompartmental knee replacement is also less desirable for a young, active person because it may not withstand the extremes of stress that high levels of activity create. It is best suited for the older, slim person with a relatively sedentary lifestyle. Only between 6 and 8 out of 100 patients with arthritic knees are good candidates for unicompartmental knee replacement. Because the unicompartmental knee replacement can be inserted through a relatively small incision (approximately 3 to 4 inches long), which does not interrupt the main muscle controlling the knee,
MINIMALLY INVASIVE KNEE REPLACEMENT
In minimally invasive knee replacement, the surgical procedure is similar, but there is less cutting of the tissue surrounding the knee. The artificial implants used are the same as those used for traditional knee replacement. However, specially designed surgical instruments are used to prepare the femur and tibia and to place the implants properly. Minimally invasive knee replacement is performed through a shorter incision—4 to 6 inches versus 8 to 10 inches for traditional knee replacement. A smaller incision allows for less tissue disturbance. Minimally invasive total knee replacement is not suitable for all patients. Your doctor will conduct a thorough evaluation and consider several factors before determining if the procedure is an option for you or not. In general, candidates for minimal incision procedures are thinner, younger, healthier and more motivated to participate in the rehabilitation process, compared with patients who undergo the traditional surgery. Minimally invasive surgeries may be less suitable for patients who are overweight or who have already undergone other knee surgeries. A patient considering minimally invasive surgery should speak with their surgeon about potential advantages and disadvantages in the context of the patient’s knee arthritis, knee anatomy, overall health and lifestyle.
WHAT TO EXPECT AFTER SURGERY?
The average hospital stay is usually 4 days for knee replacement surgery. Almost all patients show a dramatic improvement within a month. Most people report a major reduction or no pain in the damaged joint once it is replaced by the artificial joint. After knee joint replacement, many people start standing and moving the joint a day after the surgery. After about six weeks, most people start walking comfortably with minimal assistance. Once muscle strength is restored, people who have had knee joint replacement surgery can enjoy most activities except running and jumping.