Knee replacement is where portions of the bones that form the knee joint are removed and replaced with artificial implants. It is performed primarily to relieve knee pain and stiffness caused by osteoarthritis.
Total knee replacement is the more common of these two procedures.
Most arthroplasties target the entire knee joint, an operation called a total knee replacement. But some people choose to have a partial knee replacement.
To understand the difference, it helps to know the knee’s compartments, or sections. It has three:
The partial approach fixes a single section. So healthcare providers call it unicompartmental replacement. A total knee replacement addresses all three sections. Generally, only younger adults with symptoms in one knee section benefit from partial replacement.
The selection of knee replacement prosthesis design and materials depends on each individual patient. The main implant components are made of metal – usually titanium or chrome-cobalt alloys. The implants are fixated in place either with a cement bonding agent or by osseointegration, in which a porous metal stem extends into the tibia and the patient's natural bone grows into it. A plastic platform or spacer will be inserted between the tibial and femoral implant surfaces. The spacer is made of polyethylene..
Most femoral components are made of metal alloys (cobalt chromium) or metal-ceramic alloys (oxidized zirconium). The patellar component is plastic (polyethylene). The tibial insert component is also plastic (polyethylene). The tibial tray component can be made of the following materials:
The choice on whether to have surgery to address arthritis of the knee joint depends on multiple factors, including:
In cases where the damage from arthritis is minimal, and/or if the patient does not have a very active lifestyle, nonsurgical treatments by be tried, including:
You may need surgery if:
Knee replacement implants are expected to function for at least 15 to 20 years in 85% to 90% of patients. However, the implants do not last forever.
No, patients stay in the hospital one or two nights after surgery.
Knee replacement surgery, like any surgery, carries risks. They include:
Total knee replacement surgery generally takes about 60 to 90 minutes, but you should expect to be in the operating room for over two hours. Rehabilitation (physical therapy) will begin within 24 hours of surgery. After your surgery, the nursing staff will position you in bed and help you turn until you are able to move on your own. You may have a pillow between your legs if ordered by your surgeon. Very soon after surgery, a physical therapist will come to your room to teach you appropriate exercises and review your progress. Gentle exercises to improve your range of motion can help prevent circulation problems as well as strengthen your muscles.
Your rehabilitation program will begin as soon as you are medically stable and there are orders from your doctor to begin postoperative mobility. All patients begin rehabilitation within 24 hours of their surgery. Your motivation and participation in your physical therapy program is key to the success of your surgery and recovery. The physical therapist will assist you in the following activities:
Most patients progress to a straight cane, walker or crutches within two or three days after surgery. As the days progress, the distance and frequency of walking will increase. Patients are usually able to drive a car within three to six weeks after surgery and resume most other normal activities by or before six weeks. Complete recuperation and return to full strength and mobility may take four months or more. However, in many cases, patients are significantly more mobile one month after surgery than they were before they had their knee replacement
Soon after surgery, you will be able to walk with a cane or a walker. But you will need help with everyday activities, such as:
Plan ahead to have a friend or loved one help you after surgery, or you may book a package for post operative support Your recovery will also be easier and safer if you adjust your home ahead of time. Things to consider include: