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.
Partial Knee Replacement
WHAT IS PARTIAL KNEE REPLACEMENT?
During knee replacement surgery, the damaged bone and cartilage is being resurfaced with metal and plastic components. In partial knee replacement, only one part of the damaged knee is being replaced- either the inside part of the knee, outside part of the knee, or the kneecap. This procedure is an alternative to total knee replacement for patients whose disease is limited to just one area of the knee.
In a partial knee replacement, smaller incisions are involved hence patients spend less time in the hospital and resume daily activities sooner than total knee replacement patients.
WHO IS A SUITABLE CANDIDATE FOR PARTIAL KNEE REPLACEMENT SURGERY?
For a partial knee replacement surgery to be suitable, your arthritis has to be limited to one part of your knee. Additionally:
- You do not have inflammatory arthritis
- You do not have significant knee stiffness
- The ligaments in your knee are stable
- You are older, thin, and not very active
- You only have a small deformity in the knee
WHAT IS THE ORTHOPAEDIC EVALUATION FOR PARTIAL KNEE REPLACEMENT SURGERY?
A history of the injury and a physical examination of the knee will be conducted by the Doctor. He will try to find out the exact location of pain. If your pain is located almost entirely on either the inside portion or outside portion of your knee, you may be a candidate for a partial knee replacement. However if your whole knee is in pain, or the pain is located under the kneecap, a total knee replacement would be better.
An x-ray will be taken to help your doctor see the extent of the damage in your knee, and to find out the pattern of arthritis. An MRI scan may also be ordered for the doctor to better examine the cartilage.
PREPARING FOR A PARTIAL KNEE REPLACEMENT SURGERY
Before your surgery, inform your doctor on the type of medications and dietary supplements you take, if any. If you are taking any medication that makes it harder for blood clotting (aspirin, ibuprofen and blood thinners for example), you will be asked to stop taking them. Should you have specialised conditions such as heart disease, you will be required to be evaluated by your specialist as well.
Should you be staying alone, you may want 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 PARTIAL KNEE REPLACEMENT SURGERY?
Your doctor will first remove the cartilage from the damaged portion of your knee using special tools. The removed cartilage is replaced with metal components, that are attached to the bone using ‘cement’. A medical-grade plastic spacer is also placed between the metal components which acts like cartilage to help reduce friction as your joint moves.
WHAT ARE THE RISKS AND COMPLICATIONS OF A PARTIAL KNEE REPLACEMENT SURGERY?
As with any type of surgery, there are risks accompanied with partial knee replacement surgery, although rare. These include:
- Blood clotting in the leg veins (this can be prevented with blood thinners)
- Injury to surrounding nerves and blood vessels
- Infection in the wound or around the wound
- Continued pain after surgery
- Need for additional surgery
WHAT HAPPENS AFTER A PARTIAL KNEE REPLACEMENT SURGERY?
After the surgery, you may need to stay in the hospital for 1-3 days or you may get discharged on the same day, depending on your condition.
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.
A walker or crutches may be required for the first few weeks after the surgery as you may not have the strength to walk by yourself yet.
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.