An Overview of Knee Replacement Surgery
Total knee replacement, also called total knee arthroplasty, is a surgical procedure that is performed thousands of times each year. The main reasons for performing a total knee replacement are:
- To replace a worn-out knee joint
- To improve the motion of your knee
- To relieve pain.
Many conditions can cause your knee joint to wear out. The most common reason is
arthritis, which is a result of wear and tear from daily activities over time.
Your doctor will usually first recommend non-surgical treatments for a worn-out knee joint. This can include medication, activity changes, or physical therapy. If these methods have been unsuccessful at relieving your symptoms, your doctor may recommend a total knee replacement.
What Happens When the Knee Wears Out
As you get older, parts of the cartilage in your joint begin to wear out. As a result of this, the ends of your bones no longer have a smooth surface for gliding, and they begin to rub directly on each other, which causes pain. Some people have infections, injuries, or diseases, such as
rheumatoid arthritis or lupus, that may speed up this wearing-out process.
A response to this process is that your body begins to produce more fluid in the joint to protect and lubricate the knee, making it swell and feel warm to the touch. As the process progresses, your knee movement decreases and the pain and swelling get worse. Your joint can even become deformed so that the knee seems to bend in abnormal directions.
Preparing for Knee Replacement Surgery
Before your knee replacement, your doctor will ask about your medical history and any other current medical conditions you may have, including
allergies. Make sure to let your healthcare provider know if you have allergies to latex, iodine, betadine, seafood, soybeans, or any medications, such as penicillin.
Also let your doctor know beforehand if you are currently taking aspirin, blood thinners, pain medicine like
Motrin® or Advil
®, or any prescription medications. It is always helpful to have a list of your medications with you.
You will be asked not to eat or drink anything for at least eight hours before your knee replacement, and in certain cases, you may even be required to stay in the hospital the night before surgery.
Anesthesia for Knee Replacement Surgery
Anesthesia is used to eliminate the pain felt during a procedure. For total knee replacement, the anesthesia most commonly used is either spinal or general anesthesia.
With spinal anesthesia, your anesthesiologist will inject medicine into your lower back. You will also receive medicine that makes you feel relaxed or sleepy. Although the spinal anesthesia will take away all sensation of pain, you might still feel some pressure and movement during the total
knee replacement surgery.
The other option is general anesthesia. This uses medication to put you into a deep sleep so that you are not aware of any pain, pressure, or movement during the total knee replacement surgery.
In order to do this, you will first be asked to breathe through an oxygen mask. Then you will be given medications through your IV, which will cause you to feel pleasantly relaxed, and you will slowly drift off to sleep. After you are sound asleep, a breathing tube will be placed into your windpipe to assist with your breathing throughout the surgery.
How Is Knee Replacement Surgery Performed?
After anesthesia is given, your doctor will begin by making an incision along the front of your knee. The joint is opened, and the ends of your worn-out bones are exposed. The ends of the shinbone and thighbone and the undersurface of the kneecap are then removed using special cutting guides and saws.
The metal implant pieces are then selected and cemented into place at the end of the thighbone and the shinbone. A piece of plastic is then cemented to the undersurface of the kneecap, and another piece of plastic is attached to the metal of the shinbone to bear weight in the new joint. Your skin is then closed with stitches or staples, a bandage is applied, and possibly a splint, and you are awakened from anesthesia.
Implants Used for Knee Replacement Surgery
For
knee replacement surgery, a special implant, or artificial joint, is typically used to replace your knee. The implants are made of metal, normally an alloy, which is a combination of several metals.
Most implant designs use a small, specialized plastic insert between the two metal parts to act as a weight-bearing surface for the joint, much like your natural cartilage. Depending on the type of implant, bone cement may be used to fix the implant components securely into place.
Recovering From Knee Replacement Surgery
After your knee replacement surgery, you will be moved to a recovery room. In this room, you will be with other post-operative patients, and healthcare providers will be available to assist you with any problems or concerns. You will be kept here until your healthcare providers feel that you are recovering well -- usually, this is within one to two hours.
It is common to feel some pain in your knee. Pain medicine can be given to help relieve this.
Some patients experience nausea after their knee replacement surgery, which can be related to the medications used. This should not last long, but can take up to 24 hours to resolve completely.
Remember that your healthcare provider wants you to recover without any problems. So be sure to report anything that does not feel normal or "right."
Possible Complications of Knee Replacement Surgery
No procedure is ever completely free of risks; however, total
knee replacement surgery has been performed for many years with successful results and limited complications.
Minor complications are usually temporary, and are often easily treated by your healthcare providers. These minor complications can include:
- Infection
- Numbness around the incision area
- Minor bleeding or bruising
- Allergic skin reaction to tape, dressing, or latex
- Abnormal or painful scar formation
- Urinary tract infection.
Several major complications can also occur. These are uncommon; however, your overall health will play a role in your likelihood of developing any of these complications and how well you recover. For example, patients with severe
heart disease,
diabetes, lung, or kidney disease may have a higher chance of complications occurring than those who are healthier.
Depending on your individual situation, a major complication from knee replacement surgery may lead to a longer hospital stay, blood transfusion, a repeat surgery (including knee revision), or, in infrequent cases, permanent disability or even loss of life.
Knee Replacement Surgery: A Summary
Total knee replacement surgery is a commonly performed procedure for knee pain that is caused by wear and tear on your knee joint. The surgery is a safe procedure with limited complications.
With the recent advances in technology, the implanted joints last longer. When combined with physical therapy, the majority of patients have successful results and are generally satisfied with their outcome.
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