What is Knee Replacement Surgery?
Knee replacement, also called knee arthroplasty or total knee replacement, is a surgical procedure to regenerate a knee damaged by arthritis. Metal and plastic parts are used to cover the knee joint as well as the ends of the bones that make up the knee joint. This surgery may be considered for someone who has severe arthritis or a severe knee injury.
Reasons for the Knee Replacement Procedure
Knee replacement surgery is a treatment for disability and pain in the knee. The most common condition that results in the need for knee replacement surgery is osteoarthritis.
Osteoarthritis is characterized by the breakdown of joint cartilage. Damage to cartilage and bones limits movement and can cause pain. People with severe degenerative joint disease may be unable to perform normal activities that involve bending at the knee, such as walking or climbing stairs, because they are painful. The knee may swell or “give-away” because the joint is not stable.
Other forms of arthritis, such as rheumatoid arthritis and gout that result from a knee injury, can also cause degeneration of the knee joint. In addition, fractures, torn cartilage and/or torn ligaments can cause irreversible damage to the knee joint.
If medical treatments are not satisfactory, knee replacement surgery may be an effective treatment. Some medical treatments for degenerative joint disease may include, but are not limited to:
- Anti-inflammatory drugs
- Viscosupplementation injection (to add lubrication to the joint to reduce movement of the joint)
- Glucosamine and Chondroitin Sulfate
- Limiting painful activities
- Pain medications
- Walking aids (such as canes)
- Cortisone injection into the knee joint
- Physical therapy
- Weight loss (for obese people)
There may be other reasons why your doctor may recommend knee replacement surgery.
Total Knee Replacement Surgery Procedure
Read total knee replacement procedure with step by step guide.
1. Making a Knee Incision
The surgeon makes an incision in the front of your knee to gain access to the patella, commonly called the kneecap. In a traditional knee replacement, the incision is usually about 8 to 10 inches long. In minimally invasive knee surgery, the incision is usually about 4 to 6 inches long. The jury is still out on whether the advantages of a smaller scar outweigh the disadvantages of a smaller surgical field. Talk to your doctor about which procedure is right for you.
2. Rotating the patella (knee cap)
The first part of your knee that is exposed is your kneecap, called the patella. Once your knee is open, the surgeon moves the patella to the outside of the knee area. This allows the surgeon to see the area needed to perform the surgical procedure.
3. Preparation of the Femur
The first bone your surgeon will reinsert is your femur, commonly known as the thigh bone. Once the surgeon has opened and exposed your knee joint, he or she will carefully measure your bones and use special instruments to make precise cuts. The damaged bone and cartilage are cut from the end of the femur. The end of your femur is cut and resurfaced to fit the femoral component, the first part of the prosthetic knee.
4. Transplantation of the Femoral Component
The surgeon attaches a metal femoral component to the end of your femur and uses bone cement to seal it in place.
5. Preparation of the Tibia (Shinbone)
Your surgeon’s next bone is your tibia, or shinbone. The surgeon removes the damaged bone and cartilage from the top of the tibia and then shapes the bone to fit the metal and plastic tibial components.
6. Transplantation of the Tibial Component
The lower part of the implant, called the tibial tray, is fitted into the tibia and secured in place using bone cement. Once the tray is in place, the surgeon will snap in a polyethylene (medical-grade plastic) insert to sit between the tibial tray and the femoral component, and act as a buffer of sorts. This insert will support your body as you bend and bend your knee.
7. Re-adjusting the Patella
Before returning the patella to its normal position, the surgeon may need to flatten the patella and fit it with an additional plastic component to ensure a proper fit with the rest of your implant. The piece of plastic, if necessary, is cemented to the underlying bone.
8. Finalization of Process
Your surgeon will bend and flex the knee to ensure that the implant is working correctly, and that the alignment, size and position is appropriate. To complete the procedure, the surgeon will close the incision with stitches or staples, and then bandage it up and prepare you for recovery. You can leave the operating room with your foot in a continuous passive motion (CPM) machine that will gently bend and flex your new knee for you while you lie down.
Post Knee Replacement Surgery
After surgery, a patient may be taken to the recovery room for a few hours while the surgical anesthesia wears off. Afterwards a patient will be seen by a physical therapist, and if deemed appropriate, may be discharged home on the day of surgery. If the patient is not considered safe for discharge on the day of surgery, they will be admitted to a hospital room, where they will spend 1 to 2 days before being discharged.