Knee Replacement

A knee replacement or knee arthroplasty is a surgical procedure that can help relieve pain and restore function in a severely arthritic knee after non operative treatment options have been unsuccessful. Traditionally, the procedure involves cutting away damaged bone and cartilage from your femur(thighbone), tibia(shinbone) and patella( kneecap)and replacing it with an artificial joint (prosthesis) made of metal alloys, high-grade plastic spacer between the femur and tibia and behind the patella. This describes a total knee replacement. If there is severe arthritis located in only one area of the knee, a partial knee replacement may be considered.

Anatomy

The knee joint is made up of the lower end of the femur (thighbone), the upper end of the tibia (shinbone), and the patella (kneecap). The surfaces of these three bones are covered with articular cartilage, a smooth tissue that protects and cushions the bones as you bend and straighten your knee. Other important structures of the knee include:

• Meniscus: Between the tibia and femur lie two floating cartilages called menisci. The medial (inner) meniscus and the lateral (outer) meniscus rest on the tibial surface cartilage and are mobile. The menisci also act as shock absorbers and stabilizers.
• Ligaments: The knee is stabilized by ligaments that are both in and outside the joint. The medial and lateral collateral ligaments support the knee from excessive side-to-side movement. The (internal) anterior and posterior cruciate ligaments support the knee from buckling and giving way.
• Synovium: The knee joint is surrounded by a capsule that produces a small amount of synovial (lubrication) fluid to help with smooth motion.

When is surgery recommended?

The most common indication for a knee replacement is severe pain and loss of function from osteoarthritis. Nonoperative treatment for knee arthritis is always considered prior to surgery. These options include anti-inflammatory medications, cortisone injections, lubricating injections and physical therapy. Surgery may be recommended if these treatment options fail to provide relief. Patients may benefit from a knee replacement if they experience:

• Knee pain or stiffness that limits everyday activities, including walking, climbing stairs, and getting in and out of chairs.
• Moderate or severe knee pain while resting, either day or night or pain requiring the use of assistive devices such as a walker or a cane.
• Knee deformity — a bowing in or out of your knee, that impairs daily function

The decision to have knee replacement surgery is a cooperative one between the patient, the patient’s family, primary care physician, and orthopedic surgeon. Patients who have tried non operative treatments without relief from pain or disability often benefit from surgery. Recommendations for surgery are based on pain and disability it causes. Most patients who undergo surgery are between 50-80 years old but each patient’s situation and recommendation for surgery is evaluated on an individual basis.

Total vs. Partial Knee Replacement

Knee arthritis can occur throughout the entire knee joint or in a single area of the knee. The knee itself is divided into three main compartments:

• Lateral compartment-outside of the knee
• Medial compartment-inside of the knee
• Patellofemoral-front of the knee between the patella (kneecap) and femur (thigh bone)

Each of these compartments can be replaced individually in partial knee replacement surgery, or all three can be replaced in a total knee replacement. A patient may be a candidate for a partial knee replacement if the arthritis is limited to one of these compartments within the knee joint. The arthritic portion is replaced with a metal alloy prosthesis and a plastic spacer. The healthy bone and cartilage as well as ligaments within the rest of the knee are preserved.

A partial knee replacement  generally results in a better, faster recovery for patients.  Patients generally require less physical therapy. However, they are only recommended in certain cases. Cases in which a partial knee replacement no be recommended include:

• history of inflammatory arthritis
• ligament injuries
• severe deformity
• An unstable knee
• Patients who have had a previous osteotomy
• arthritis in one or more areas of the knee

A total knee replacement may be the preferred surgical option if you have one of the conditions mentioned above. When there is a possibility that a patient’s knee problems will get worse over time, which is usually the case, a partial knee replacement patient may eventually need a total knee replacement.

For patients who are not candidates for a partial knee replacement, a total knee replacement offers a successful solution to improve overall quality of life. In a total knee replacement, the damaged or arthritic cartilage from your femur(thighbone), tibia(shinbone) and patella (kneecap) is cut away and replaced with an artificial joint (prosthesis) made of metal alloys. A high-grade plastic spacer is placed between the femur and tibia and behind the patella. Benefits of a total knee replacement include:

• Severe pain that limits your everyday activities including walking, shopping, visiting friends, getting in and out of chair, gardening, etc.
• Pain waking you at night
• Deformity- either bowleg or knock knees
• Stiffness

Both partial and total knee replacements can be highly successful for patients who are good candidates. It is important to discuss the risks and benefits of each type of surgery with your surgeon so that your expectations are in line with the procedure you elect to have.

Expectations

It is important when deciding whether surgery is right for you, what to expect following a knee replacement. The majority of people experience a significant reduction in pain and restores the ability to perform activities of daily living. A knee replacement is not meant to give you the knee you were born with prior to developing arthritis. Knee replacements can last for many years. However, excessive activity or weight may speed up this normal wear and may cause the knee replacement to loosen and become painful. Therefore, most surgeons advise against high-impact activities such as running, jogging, jumping, or other high-impact sports for the rest of your life after surgery. Activities such as walking, swimming, golf, driving, light hiking, biking, ballroom dancing, and other low-impact sports can be done without limitation following surgery.

Risks and Complications

As with any major surgery, there are potential risks involved. The decision to proceed with the surgery is made because the advantages of surgery outweigh the potential disadvantages. The risk of complications are generally low for knee replacement surgery. Major medical complications such as heart attack or stroke occur even less frequently. Chronic illnesses may increase the potential for complications. Although uncommon, complications can be serious and affect the recovery process. These medical and surgical complications include:

• Blood loss during surgery requiring transfusion
• Infection
• Blood Clots
• Wound complications
• Failure or loosening of the prosthesis
• Fracture around the prosthesis
• Need for additional surgery-in the case of a partial knee replacement
• Damage to nerves and blood vessels around the knee.

This is not a complete list of the complications. You should be aware and understand all of the risks related to surgery prior to proceeding.

Prior to Surgery

Once you have decided that you would like to proceed with knee replacement surgery there will be some steps you need to take. You will need to undergo a complete physical examination with your family physician several weeks before the operation. This is needed to make sure you are healthy enough to have the surgery and complete the recovery process.  You will need to get bloodwork and oftentimes a chest X Ray. Many patients with chronic medical conditions, like heart disease, may also be evaluated by a specialist, such as a cardiologist, before the surgery. You will need to make sure your A1C and blood sugar levels are controlled if you have diabetes. You must stop smoking prior to surgery.

Prior to surgery you will need to stop certain medications that can affect bleeding risk such as NSAID medications and certain supplements. You should arrange to have your routine dental work done prior to surgery. You should also make arrangements with your workplace and to have help around the house following surgery. Home health care and home physical therapy is often arranged for patients for the first few weeks after surgery.

Day of Surgery

On the day of surgery you will be admitted to the hospital. Occasionally if you are healthy  enough, your procedure may be performed at a surgery center where you are able to go home the same day. You will meet with the anesthesia team to discuss your options and what type of anesthesia is best for you. You will see your surgeon and the OR team. The procedure generally takes 1-2 hours. Following surgery, you will be taken to the recovery area for monitoring.

If you have surgery at the surgery center, you will be discharged home once the nurses  and physical therapy team are certain your vital signs are stable and you are able to walk without difficulty or safety concerns. If you are staying in the hospital, you will be transferred to the floor where nurses will monitor your condition. Physical therapy will have you begin exercises and start walking with the assistance of a walker or crutches. Most people stay one night in the hospital.

Post-operative Recovery

At both the hospital and surgery center, the nurses will give you breathing exercises to ensure that you take deep breaths to prevent a condition called atelectasis which can lead to pneumonia. You will be given compression stockings and the physical therapy team will have you moving early on after surgery, decreasing the amount of time you spend in bed, to help decrease the risk of blood clots following surgery.

Following surgery you will need to keep the surgical dressing clean and intact. The dressing is often waterproof meaning you may shower. You should not submerge your knee (pools, baths, hot tubs) until your surgeon indicates it is safe to do.

You will be given medication to help with pain following surgery as well as medication to help reduce the risk of blood clots.

During the recovery process, most patients use some form of aide for walking. This usually a walker or crutches initially, followed by a cane.

Physical therapy is a crucial part of the post operative recovery process. Most patients will have visits with physical therapy multiple days per week for several months to regain range of motion, function, and strength. Patients usually have home physical therapy for the first two weeks and then transition to outpatient physical therapy.

You will have routine follow up visits after surgery to monitor your progress. Xrays are taken periodically to ensure there are no issues with the prosthesis. These visits are usually at the 2 weeks, 2-3 month, 6 month, and 1 year mark. Yearly follow up visits follow.

Routine dental visits are not recommended for the first three months after surgery. Having a prosthesis puts you at higher risk of infection. You will need antibiotics prior to any dental work you have done, including cleanings. If you ever have any unexplained pain, swelling or redness or if you feel generally poor, you should see Dr. Faucett as soon as possible.

In some cases, the symptoms of knee arthritis may disappear as early as two to three weeks after surgery, but it may take up to six months to achieve full recovery. Usually throughout the recovery process pain steadily decreases. It is important to follow your surgeon’s instructions and be active in the recovery process in order to get the best result possible following surgery.