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We tend not to realize how much we rely on our joints—especially our knees—when doing even the simplest of tasks. When a knee has been injured or develops a medical condition, the resulting pain and discomfort can make it difficult to live life normally. In such cases, an orthopedic surgeon may recommend a total knee replacement.
At Banner CORE Center for Orthopedics in Phoenix, AZ, our expert surgeons can help you diagnose your knee’s condition as well as correct the damage with a total knee replacement.
Knee Anatomy and Background
The knee is the largest joint in the body. Your knee helps you perform most everyday activities. The knee is made up of the lower end of the thighbone (femur), which rotates on the upper end of the shin bone (tibia), and the kneecap (patella), which slides in a groove on the end of the femur. Large ligaments attach to the femur and tibia to provide stability. The long thigh muscles give the knee strength.
Normal Knee Anatomy
The joint surfaces where these three bones touch are covered with articular cartilage, which is a smooth substance that cushions the bones and helps them move easily.
All other surfaces of the knee are covered by a thin, smooth tissue liner called the synovial membrane. This membrane releases a special fluid that lubricates the knee, reducing friction to nearly zero in a healthy knee.
Normally, all of these parts work in harmony. But disease or injury can disrupt this harmony, resulting in pain, muscle weakness, and reduced function.
The most common cause of chronic knee pain and disability is arthritis. Osteoarthritis, rheumatoid arthritis and traumatic arthritis are the most common forms of this disease.
- Osteoarthritis usually occurs in people age 50 and older and often in individuals with a family history of arthritis. The cartilage that cushions the knee bones softens and wears away. The bones then rub against one another causing knee pain and stiffness.
- Rheumatoid arthritis is a disease where the synovial membrane becomes thickened and inflamed, producing too much synovial fluid that overfills the joint space. This chronic inflammation can damage the cartilage and eventually cause cartilage loss, pain and stiffness.
- Traumatic arthritis can follow a serious knee injury. A knee fracture or severe tears of the knee ligaments may damage the articular cartilage over time, causing knee pain and limiting knee function.
When non-surgical treatment doesn’t help arthritis or if the arthritis is advanced, a joint replacement is a possible option. During surgery, the diseased bone ends of the femur and tibia are cut away and replaced by a smooth metal covering. A plastic liner, which acts like a shock absorber, is placed between the metal components. The arthritis on the back of the patella is also removed and replaced with a small piece of plastic. All of the metal and plastic components are fixed into place with special bone cement and patients can walk on the surgical knee immediately after surgery.
Preparing for a Full Knee Replacement
In preparation for the surgery, the patient will need to undergo a full examination with his or her primary physician to clear them as healthy enough to have the surgery. This will usually include a standard physical exam, a discussion of the patient’s medical and surgical history, and any testing or imaging (e.g., x-rays, MRIs) that may be necessary.
Before the surgery, the patient should also prepare for recovery by arranging for any necessary transportation or household assistance, as well as make sure that any hazards are removed from the home. If these arrangements cannot be made at home, the patient can also make plans with a rehabilitation facility for the first few weeks after surgery.
The Total Knee Replacement Procedure
During the actual surgery, the orthopedic surgeon will open up the knee (either via a long front incision or smaller, minimally invasive incisions) and use a bone saw to remove the damaged bone and remove the joint. Once this joint is removed and the bones have been re-shaped to fit the prosthetic, the new artificial knee joint will be implanted and fixed in place (usually with bone cement). Before closing up the patient, the knee will be flexed and tested, then straightened to allow everything to set in place.
Robotic Total Knee Replacement
Another exciting development in minimally invasive knee replacement surgery is the use of computer guidance and robotics. Surgeons can increase accuracy and minimize certain risks using tools like the MAKO surgical system, which is currently available to patients at the Banner Del Webb, Banner Estrella, and Banner University Medical Center – Phoenix locations.
Starting with a full CT scan of your knee joint, the MAKO system develops a 3D model that your surgeon can use to plan for the procedure. The surgery itself is then performed using a robotic arm, which is automatically guided by the system to the right areas and is restricted to working within defined boundaries. This robot-enabled surgery helps human surgeons achieve the most accurate, steady-handed results when placing and aligning your new prosthetic knee.
This means, less disruption of the soft tissue in the knee to ensure there is equal amount of tension throughout the range of motion of the knee.
What Is Total Knee Replacement Surgery and When Is It Necessary?
In a full knee replacement procedure, the entire knee joint is replaced with a prosthetic joint made from metal and plastic. There are a variety of conditions that may necessitate joint replacement surgery, including arthritis, chronic inflammation, knee deformity, or athletic injury. If knee pain and reduced mobility do not respond to physical therapy, medications, or other treatments, a knee replacement is often the best course of action.
Risks Associated with Primary Knee Replacement Surgery
Knee replacement surgery has a relatively high rate of success, with as many as 90% of patients experiencing significant pain relief. Any surgery presents some risks, but serious complications, on the other hand, are quite rare. Potential risks may include nerve damage, implant malfunctions, infection, or blood clot and occur in fewer than 2% of patients.¹ Life-threatening risks like heart attack and stroke are even less likely.
The success of your surgery will greatly depend on how well you follow your orthopedic surgeon’s
instructions for hospital and home care during the first days to few weeks after surgery.
Hospital Care Plan:
- Work with your care team to manage pain effectively.
- Begin Physical Therapy immediately after surgery.
- Plan to be discharged 24 hours post-surgery.
In Home Care Plan:
- Participate in a regular light exercise program to maintain strength and mobility
- Take special precautions to avoid falls and injuries.
- Notify your dentist about your orthopedic surgery and discuss whether you need to take antibiotics before any dental procedures.
- See your orthopedic surgeon for all scheduled follow-up appointments and periodic checkups.