There are three primary goals of having a total knee replacement:
- Eliminate pain in the knee
- Improve mobility/motion in the knee
- Improve quality of life
What is the goal of total knee replacement?
How do I know when I'm ready for a total knee replacement?
A total knee replacement is an elective surgery, meaning you never HAVE to have one. The choice and timing is different for each patient. We recommend a total knee replacement for you when your mobility is limited, your pain is affecting your quality of life, and your examination and x-rays suggest these are being affected by a knee problem, typically an arthritic condition.
You can continue non-operative treatments such as medications, injections, therapy, and bracing for as long a time period as is effective for you. In some situations these therapies are unlikely to be helpful and surgery may be the best option. Once non-operative treatments become ineffective, surgery is the next step.
A total knee replacement involves removing the remaining articular cartilage on the end of the femur, tibia, and patella (knee cap) bones and replacing this with metal and plastic (polyethylene) pieces. The metal and plastic pieces move smoothly over one another to restore motion of the knee.
The two metal pieces are typically made of cobalt chromium or titanium. These are placed on the end of the femur and tibia bones. In some special circumstances, other metals are used. The reason these metals are selected is because they do not create adverse reactions in the body. Bone cement is used to hold the components in place.
The plastic used in knee replacement is called polyethylene, which is a plastic polymer that has been processed to create a smooth surface with low wear characteristics. Two pieces are used, one on the back of the patella (knee cap) and one between the femur and tibia components.
What exactly is a total knee replacement?
There are two current general methods Dr. Foster uses to perform knee replacement: manual and robotic
Manual knee replacement involves various measurement tools that are used during surgery to decide how to balance the knee and make the appropriate cuts. They depend on using anatomic landmarks and the human eye to make decisions.
Robotic knee replacement involves obtaining a pre-operative CT scan of the knee, then using intra-operative data points to balance the knee and make appropriate cuts. Subtle adjustments can be made prior to making any cuts. Even small adjustments can make a major difference in the balance and motion of the knee. There is evidence that this method could be more accurate than manual instrumentation.
Methods of Performing Knee Replacement
- The surgery takes between 1 and 2 hours depending on the difficulty.
- The incision is typically centered over the front of the knee and varies in length based on the difficulty of exposure. Smaller incisions offer no improvement in pain or recovery.
- All absorbable sutures are used, so there are no sutures or staples to be removed in the office. A tissue glue may be used over your incision to create a waterproof seal, however you should not submerge your incision until it is healed, usually 3-4 weeks after surgery.
- An antibiotic is used through your IV just prior to surgery to reduce risk of infection. We use methodical sterile technique throughout the surgery to further reduce this risk.
- A local anesthetic is used during your surgery to reduce pain levels for up to 48 hours.
- Either general or spinal anesthesia can be used, which is determined by your anesthesiologist. The anesthesiologists may also administer a "regional block" for extra pain control, which is a procedure to reduce pain in the front of the knee.
Total Knee Replacement Surgical Details:
- Typically you will stay between 1-2 nights in the hospital. The length of hospitalization is different for every patient and is based on pain control, progress with physical therapy, and general medical condition.
- Physical therapy starts, in most cases, on the same day as your surgery. Your therapist will help you stand and walk, and work on the motion in your knee. This will continue once you leave the hospital as well.
- We prefer for most patients to go to their own home following discharge from the hospital. In some special circumstances, you may go to a skilled nursing facility for a short time.
Total Knee Replacement Hospitalization Details
Physical therapy is IMPERATIVE after knee replacement. Your recovery and ultimate range of motion depends on the first 6 weeks of therapy. It is very important you attend your sessions and work on your exercises at home.
Goals are to get the knee completely straight (full extension) and 90 degrees of knee bend (flexion) by 4 weeks. By 6 weeks, the knee should bend at minimum 105 degrees, but the goal is beyond 120 or 130 degrees. At 6 weeks, Dr. Foster will assess your motion. If it is not adequate, he may have to "manipulate" the knee, which is performed under anesthesia, and involves manually moving the knee to break up scar tissue. This can be avoided by diligent exercise after surgery.
Physical Therapy after Knee Replacement
Short term recovery is different for every patient, and is based on your pre-surgery conditioning level and overall medical condition.
You will start by walking with a walker or cane in the hospital. Most patients have stopped using the cane by around 4 weeks after surgery, but this is variable as well. If you need a cane for a longer period of time, you are not behind and it does not necessarily signify a problem in your recovery.
You will continue physical therapy to improve your range of motion and strengthening for around 3 months after surgery, and can continue if necessary after that.
If generally takes about 3 months for you to return to your pre-surgery conditioning level so that you are able to perform activities without limitation. Maximal recovery is seen at one year.
Your entire leg can be swollen for up to a month. This does not necessarily signify a problem. Painful swelling in the calf area can be worrisome, so you should come to our office to be evaluated if that is the case. The only intervention found to be effective in reducing swelling after surgery is the Geko device, which is a small band worn around the knee that creates muscular contractions. Unfortunately, this is not covered by insurance companies. You can purchase the recovery pack of Gekos, 10 total devices, for $250. These devices also help reduce the risk of a blood clot (DVT).
How long does it take to recover from a total knee replacement?
We typically allow patients to drive at 4 to 6 weeks after surgery, and sometimes sooner if the operative leg is the left leg. There is some literature that states that your reaction time will not be back to normal prior to 6 weeks. You should not drive while on narcotics.
When can I drive after a total knee replacement?
Returning to work is highly dependent on your general health, activity level and demands of your job. If you have a sedentary job, such as computer work, you can expect to return to work by 4-6 weeks. If you have a more demanding job that requires lifting, walking, or travel, you may need up to 3 months for full recovery.
When can I return to work after total knee replacement?
Typically we let you shower two days after surgery. However, you should not submerge your incision until it is healed, which will be around 3-4 weeks after surgery.
When can I shower after total knee replacement?
The only major restrictions you have after total knee replacement are no running or jumping.
Walking long distances, skiing, surfing, cycling, golfing are all fine and we encourage you to pursue an active lifestyle following your surgery.
What restrictions do I have after total knee replacement?
Typically the knee does not retain the normal contour after surgery, so it may look different than the opposite knee.
You will have a scar in the front of your knee. It is impossible to perform surgery without a visible scar. We use every technique available to minimize the size of your scar while providing a safe and effective knee replacement.
What will my knee look like after surgery?
There is no way to accurately state how long your knee replacement will last. This varies by patient, life circumstances, surgical technique, and a variety of other factors.
The most helpful way to think about this is with overall probabilities from large studies:
- There is a 90-95% chance your knee will be functioning well at 10 years.
- There is an 80-85% chance your knee will be functioning well at 20 years.
How long will a total knee replacement last?
No surgery is without risks. Overall risk of complications are about 1-2% of cases. The risks of a total knee replacement include:
- Bleeding - it is very uncommon to need a blood transfusion after total knee replacement, but it is a risk. We would only administer a blood transfusion if absolutely necessary and would need your consent to do so.
- Fracture of the bone - this would be treated depending on the severity, and would range from limiting your weight bearing to an additional procedure to fix the bone and allow it to heal.
- Loosening or wear of the implants - total knee replacements typically last a very long time. In most circumstances, this will be the only surgery you need. However, loosening of the implants (becoming unbonded from the bone) or wear of the plastic (polyethylene) inserts can occur many years after. These situations typically require another, or revision, surgery.
- Infection - this is the most worrisome of the possible complications. A deep infection in a knee replacement is a serious problem and is typically treated surgically and may require removal of the implants. We take multiple precautions to prevent infections before, during, and after the procedure.
- Stiffness - it is possible you will not regain full motion in your knee. In most cases, this is only a small difference. If your knee becomes very stiff after surgery and does not improve by 6 weeks, a short manipulation procedure under anesthesia may be undertaken to improve motion.
- Blood clots - blood clots in the leg (deep venous thrombosis, or DVT) are a serious concern after knee replacement, but are also uncommon. We use multiple methods to prevent this occurrence during and after the procedure. The most effective way to reduce the risk of blood clots is with early mobilization. You will also take a medication for 4-6 weeks after surgery to reduce the risk of blood clots, typically aspirin. the Geko device offers another layer of protection against blood clots, but stimulating muscular contractions. It is a band work around the knee. Unfortunately, it is not covered by insurance companies, and a pack of 10 can be purchased for $250. It is not mandatory but it is highly recommended by Dr. Foster.
What are the risks of a total knee replacement?
There are no specific activities or therapies you need to do before surgery to get ready.
However, you should engage in a healthy lifestyle with a proper diet. If you are overweight, reducing your weight can substantially reduce your risk of infection and other risks. If you are diabetic, keeping your Hgb A1c level as low as possible will reduce your overall risk as well.
What can I do before surgery to reduce the risks of total knee replacement?
This is a very controversial topic. Some surgeons prefer to have their patients have antibiotics prior to dental procedures, some prefer this practice for 2 years after surgery, and some do not recommend this procedure.
If your dentist wants you to have antibiotics, that is fine. They will be the one to prescribe them. It is our feeling that you do not need antibiotics prior to dental procedures, but it is a safe practice to do so. We will not be providing antibiotic prescriptions for this situation, so your dentist must provide if to you if he or she wishes you to have them.
Do I need antibiotics before going to the dentist?
Probably. It is reasonable to inform the agent at the airport or other facility that you have a knee replacement, and you will need to follow their instructions. There is no official document you need to carry with you stating you had a knee replacement.