The knee is one of the largest and most complex joints in the body. The knee is made up of bones, cartilage, ligaments, and tendons. The knee joins the thigh bone (femur), the shin bone (tibia), the smaller bone that runs alongside the tibia (fibula) and the kneecap (patella) altogether to make up the knee joint. The knee is a synovial joint, meaning it contains a fluid-filled capsule.
Tendons connect the knee bones to the leg muscles that move the knee joint, and ligaments join the knee bones and provide stability to the knee.
Total Knee Replacement
WHAT IS TOTAL KNEE REPLACEMENT?
The knee is the largest joint in the body and having healthy knees is required to perform most everyday activities. However, if your knee is severely damaged from an injury or conditions such as arthritis, you will feel pain in your knees performing simple daily activities such as walking and climbing stairs, and even when sitting or lying down.
Should nonsurgical treatments like medications and walking supports not help, you may want to consider total knee replacement surgery. A total knee replacement is a surgical procedure whereby the diseased knee joint is replaced with artificial material.
WHEN SHOULD TOTAL KNEE REPLACEMENT SURGERY BE CONSIDERED?
Total knee replacement surgery is a major surgery. People who are recommended to go for a total knee replacement surgery often have:
- Severe knee pain or stiffness that affects daily activities, including walking, climbing stairs, and sitting down. At times, it may be necessary to use a cane or walker
- Deformity in the knee
- Moderate / severe knee pain while resting, either day or night
- Chronic knee inflammation and swelling that does not improve with rest or medications
- Failure to substantially improve with other treatments such as anti-inflammatory medications, steroid (cortisone) injections or physical therapy
Candidates for surgery are based on the patient’s disability and pain condition. Most people who undergo a total knee replacement surgery are between the ages of 50 to 80 years old, but there have been successful surgeries performed for all ages.
PREPARING FOR A TOTAL KNEE REPLACEMENT SURGERY
Before your surgery, you will be required to do a physical examination several weeks before. Should you have specialised conditions such as heart disease, you will be required to be evaluated by your specialist as well. It is also important to inform your doctor on the type of medications and dietary supplements you take, if any.
Tests such as blood and urine samples may be taken before the surgery. As you will require assistance the first few weeks after the surgery, do make the necessary arrangements with a family member or friend should you stay alone. You may also need to modify your home to make it easier to move around during your recovery. For example, installation of handle bars in the shower, having wide open spaces in your house and a toilet seat riser with arms if you have a low toilet.
WHAT HAPPENS DURING A TOTAL KNEE REPLACEMENT SURGERY?
In a total knee replacement surgery, both sides of your knee joint are replaced. After making a cut in the front of your knee, the end of your thigh (femur) bone is removed and replaced with a metal shell, while the end of the lower leg bone (tibia) is also removed and replaced with a flat metal plate. These are attached to the bone using special “bone cement” or are treated to increase chances of the bone fusing with the parts. A medical-grade plastic spacer is also placed between the metal components which acts like cartilage to help reduce friction as your joint moves.
Depending on the condition of the kneecap (patella), it may or may not be resurfaced. During resurfacing, a plastic “button” is added under the kneecap surface.
WHAT ARE THE RISKS AND COMPLICATIONS OF A TOTAL KNEE REPLACEMENT SURGERY?
As with any type of surgery, there are risks accompanied with total knee replacement surgery, though low (fewer than 2% of patients). These include:
- Infection of the wound or around the prosthesis
- Blood clotting- blood clots in the leg veins may travel to the lungs, which can be life threatening
- Implant wear and tear- these components may wear down and loosen
- Limited motion and scarring of the knee
- Continued pain after surgery
- Neurovascular injury
WHAT HAPPENS AFTER A TOTAL KNEE REPLACEMENT SURGERY?
Medications will be prescribed to help with managing the pain after surgery. This includes NSAIDs, acetaminophen and local anaesthetics. To help prevent blood clotting, you may be asked to wear compression boots or consume blood thinners.
Physiotherapy is also encouraged to get some movement into your foot, so as to increase the blood flow in your leg muscles to prevent blood clotting. Physiotherapy will also help you regain strength in your leg to restore knee movement and mobility.
A device called a continuous passive motion (CPM) exercise machine can also help speed up recovery. The CPM machine is attached to the leg and constantly moves the knee through various degrees of range of motion for hours while the patient relaxes. This helps to improve blood circulation and decrease leg swelling.
TAKING CARE OF YOUR NEW KNEE
To avoid problems after surgery, the following measures can help you take care of your new knee:
- Avoid taking the stairs
- Keep using walking aids such as crutches and walking canes until you regain your strength and balance
- Participate in regular light exercise programs to maintain proper strength and mobility of your new knee
- See your orthopaedic surgeon periodically for a routine follow-up examination and x-rays