What Is Total Knee Arthroplasty?

Total knee arthroplasty (TKA), also known as total knee replacement, is a surgical procedure in which parts of the knee joint are replaced with artificial parts or prostheses.

A normal knee usually functions as the hinge joint located between the lower leg bones (tibia) and the upper leg bone (femur). The surfaces of these bones may come together and worn out over time. This is commonly caused by arthritis or other knee joints conditions, which cause pain and swelling of the knee joint.

Reasons for a Total Knee Arthroplasty (TKA)

Total knee arthroplasty is a procedure that is aimed to relieve knee pain and restore the function of an arthritic knee.

Most people undergo total knee replacement primarily to treat knee pain associated with arthritis, especially when all other treatments such as medicine, weight loss, physical therapy, and injections have failed. A total knee replacement successfully cures pain and improves one’s quality of life since it aims to correct knee function.

This surgery can be performed on patients of all ages except children due to the fact that their bones are still growing. One should experience disability or significant pain first before a surgeon considers total knee replacement.

Preparation for TKA

Total knee arthroplasty is a procedure performed under general or regional anesthesia. The type of anesthesia used solely depends on the patients’ medical condition. However, some of the side effects such as mortality rates and cognitive functions associated with general and regional anesthesia have not been proven to be different.

Equipment for TKA

Different types of prostheses used in TKA include:

• PCL-substituting
• Medial pivot
• Posterior cruciate ligament
• Fixed-bearing
• Mobile-bearing rotating platform

Patient Evaluation

An evaluation should be made to the patient prior to a total knee replacement. The tests done include:

• Laboratory Tests/Studies - They include serum electrolytes, complete blood count (CBC), renal function studies, erythrocyte sedimentation rate, prothrombin time, activated partial thromboplastin time (aPTT), urine culture, and urinalysis.

• Medical Evaluation - This is done to make sure the patient has a good cardiopulmonary function to help withstand the anesthesia and also cope with the blood loss. Preoperative electrocardiography is also routinely performed to older people.

• Imaging Tests - They include long leg radiographs, standing anteroposterior view, patellofemoral view, lateral view, and standing radiographs, which is also known as the Rosenberg view.

Total Knee Arthroplasty Procedure

As mentioned earlier, TKA is performed under general or regional anesthesia. The surgical procedure takes 2-3 hours to complete. The following are the steps followed during the operation:

• The surgeon uses the medial parapatellar approach. Some surgeons will use a subvastus or lateral approach.
• A perpendicular cut to the mechanical axis is then made on the distal femur by use of an intramedullary alignment system.
• A cut is made on the proximal tibia but perpendicular to the mechanical axis of your tibia. This cut is made through the use of either extramedullary alignment rods or intramedullary.
• The restoration of the mechanical alignment is very important to allow optimal load sharing and also prevent eccentric loading with the prostheses.
• A sufficient bone is taken off to allow space for the prostheses.
• Ligaments found in the knee are then brought together to prevent preoperative deformity. They are later released in a stepwise fashion.
• Patellofemoral tracking is done in situ with trial components and then balanced with a medial reefing process.
• In case there is a complete damage to the patellofemoral joint, it is resurfaced with a polyethylene piece.
• One of the best prostheses are selected and cemented in place.
• Foot pulses are finally accessed by the end of the procedure.

Recovery

After a total knee arthroplasty, you are encouraged to move your ankles and feet immediately after the operation. Some devices are used to create a passive motion that lowers and raises your leg slowly. You can also begin a physical therapy immediately after the surgery. Physical therapy is very important for your quick recovery. You can have it even after leaving the hospital.

A rehabilitation program is also important to improve your motion through exercises. You can have rehabilitation at home or at a clinic. The main aim of rehabilitation after a total knee arthroplasty is to strengthen the movement of your knee. You can resume your normal activities 3 -6 weeks after surgery.

Potential Complications of TKA

There are no serious complications linked to total knee arthroplasty. However, it is important for you to know the major side effects and complications you can have after the operation.

According to recent scientific research, successful replacement of your knee joint may partially depend on the experience of the surgeon, the instruments used, and facilities of the hospital. In one study, good outcomes were found in people who had:

• A surgery in a hospital that performs more than 25 joint replacements per year.
• A surgeon who had done more than 5 operations per year.

The so-called good outcomes are better knee function and reduced complications after the surgery. Possible complications you may encounter after a total knee replacement include:

• Blood Clot - After a knee surgery, you have a higher risk of getting a blood clot in your veins. The medical term for this condition is thrombosis. Thrombosis is likely to occur in the deep veins located in your legs. This is referred to as deep vein thrombosis. The symptoms of deep vein thrombosis are leg pain and inflammation or swelling. If you experience such symptoms after a knee replacement, you should contact your doctor immediately.

• Infection - Infection after a knee surgery is very rare, but still a dangerous complication. The signs of an infection include chills, fever, pain in your knee that intensifies with time along with swelling and redness on the knee joint. You should seek medical attention in case you have these symptoms. You can treat such infections with antibiotics and also by draining excess fluids that may have accumulated in the joint.

• Early Failure - According to studies, about 80-90 total knee replacements are successful. However, early failures after surgery may occur due to infection, fractures present on the bone around the implants, loose implants, and instability. In case of an early failure, revision surgery is needed.

• Stiffness - Sometimes, your knee may fail to straighten or bend properly even after physical therapy. If such a condition occurs, the patient should get back to the operating room to straighten or bend the leg under anesthesia.

The Bottom Line

Total knee arthroplasty is a procedure that is aimed to relieve knee pain and restore the function of an arthritic knee. The major reason to have a total knee replacement is to treat knee pain associated with arthritis, especially when all other treatments such as medicines, weight loss, physical therapy, and injections have failed. A total knee replacement successfully cures pain and improves one’s quality of life since it aims to correct and maintain knee function.