If your knee is damaged by injury or arthritis, even walking or climbing stairs may be painful. You could even feel pain when sitting or lying down. If non-surgical treatment options like medications, walking aids such as a cane or walker and physical therapy are no longer helpful, you may wish to consider knee replacement surgery. Knee replacement surgery can relieve pain and help you return to normal activities. It may even correct leg deformities.
More than 600,000 knee replacement surgeries are performed in the United States each year. The knee is the largest joint in the body. It is made up of the thighbone (femur), the upper end of the shin bone (tibia) and the knee cap (patella). These three bone ends are covered with cartilage to protect the bones and help them move easily. There are also “cushions” between the femur and tibia called menisci. Stability is provided by ligaments and thigh muscles. A membrane covers the surfaces of the knee reducing friction in a healthy knee.
When one or more of these components are not functioning well because of injury or arthritis, pain, muscle weakness and reduced function such as difficulty walking or completing the day’s activities can occur.
What is Knee Replacement Surgery?
Four steps occur during knee arthroplasty (knee replacement), which is truly knee resurfacing. Damaged cartilage at the ends of the femur and tibia is removed. Metal components are cemented or press-fit to the new surface. The underside of the patella (knee cap) is maybe resurfaced depending on the amount of damage. A plastic spacer is inserted to create a smooth gliding surface.
What are the Different Types of Knee Replacement Surgery?
There are several types of knee replacement surgery. Your doctor and orthopedic surgeon will help you to choose the option that’s best for you based on the condition of your knee and your overall health.
- Partial (Unicompartmental) Knee Replacement – A partial knee replacement utilizes a minimally invasive approach which employs a smaller incision and less damage to the surrounding tissue when compared to a traditional total knee replacement. During a total knee replacement, patients have all of their cartilage in the knee removed and replaced by metal or plastic components. In a partial replacement, only the most damaged elements in the knee are removed and replaced by metal or plastic components. The healthy and functional elements of the joint are left remaining intact.
- Total Knee Replacement – In a total knee replacement, the cartilage and bone that have been damaged are removed. The healthy bone and cartilage are resurfaced and left to support the artificial components that will be implanted. Damaged cartilage at the ends of the femur and tibia is removed. Metal or plastic components are cemented or press-fitted into the new surface. The underside of the knee cap may also be resurfaced depending on the amount of damage. A plastic spacer is inserted to create a smooth gliding surface. During knee replacement surgery, all knee joint damage will be removed, the healthy joint will be resurfaced and the different parts of your prosthesis will be put in place.
When is it time for Knee Replacement?
All persons, regardless of age or weight may be evaluated for knee replacement. It may be time to discuss knee replacement with your doctor if you:
- Have severe knee pain, stiffness and difficulty walking and climbing stairs
- Experience moderate or severe knee pain even when resting
- Have chronic knee inflammation and swelling that are not improved with medication or rest
- Have bowed knees (in: knock-kneed or out: bow-legged)
- Find no improvement in symptoms with anti-inflammatory medications, physical therapy, cortisone injections, lubricating injections or other surgeries
Orthopedic surgeons evaluate each patient’s appropriateness for total knee replacement surgery based on these factors, as well as radiographic films (x-rays) and the physician’s professional judgement.