Are you experiencing knee pain? Is your doctor talking to you about knee replacement surgery? Continue reading to understand what you should expect from surgery and the rehabilitation process after a total knee replacement surgery.
A normal healthy knee is designed to withstand the demands of your life. You should be able to walk, stand, kneel, squat and perform all the activities required throughout your day. If this is not always the case and knee pain begins to significantly limit you from doing what you love to do or even preventing you from doing what you need to do with everyday tasks, you may want to consider your treatment options.
What is degenerative joint disease?
Your doctor may have used this term with you before, but do you understand what it means? The knee joint is made up of 3 bones: the thigh bone/femur, the shin bone/tibia and the knee cap/patella. Each bone is lined with hyaline cartilage, which asks as a friction reducer for the articulating bone surfaces. There is a joint capsule that surrounds the bones and inside is synovial fluid that serves as a lubricator for the joint. Another important structure is the meniscus. The medial and lateral meniscus sit on the tibia and act as a shock absorber within the knee. There are 4 main ligaments within the knee structure that provide lateral and rotational support to the knee joint.
With aging, the body goes through degenerative changes, which can affect the function of each of these structures. One effect of degenerative changes is the space between your joint narrows. This can be seen on x-rays. Your doctor may use the term that your knee is now “bone on bone.” Well your knee was always one bone articulating with another bone, but what that statement really means is the hyaline cartilage has been worn down and is no longer protecting the bone surface. The nerve endings in the bone structure become exposed and generate pain. With wear and tear, the meniscus can fray and you can even have tears in the meniscus, which can generate pain with movement. As the mechanics of the knee become compromised and excessive stress and wearing occurs with your bone the surfaces begin to become rough and you can get osteophyte formation. This is excessive and irregular bone formation that transforms smooth surfaces into rough and decreases shock absorption and the ease of articulation between the two bone surfaces.
Can I reverse these changes?
Once these degenerative changes occur you cannot change the damage already done, but you can slow down the process and reduce further damage by pursing several options.
Muscle strength, joint mobility and muscle flexibility have a significant impact on knee function. Typically, you do not always want to pursue knee replacement as the first option and it would be a good idea to seek more conservative measures by seeking out the help of a physical therapist who can perform a comprehensive examination to determine if there are any deficits that need to be addressed. For some people the damage has been done and conservative care is unsuccessful and surgery is the most appropriate option.
What happens during a total knee replacement?
During surgery the doctor will cut and shave the bone and will remove the rough bone surfaces that have degenerated. The bone ends will be shaped and prepped for the new joint parts. The joint replacement consists of 3 components, two metal and one plastic. The metal components are often made of cobalt chromium or titanium alloy. The upper component is metal and attaches to the femur/thigh bone. In the tibia a hole is drilled and a metal rod is inserted. Attached to the metal rod is a plastic component, which is usually made out of polyethylene. This component serves to cushion the knee and allows for smooth and easy articulation.
Not all knee replacements require work to be done to the patella or kneecap. If there is significant degenerative changes to the patella then the surface will be smoothed and the bone will be resurfaced with a plastic component.
What happens with rehabilitation after a knee replacement?
After surgery you will undergo physical therapy. Depending on what time your surgery is, usually you will have an afternoon session of physical therapy on the same day you have your surgery. It is important to get you up and moving as soon as possible. Typically hospital stays after a total knee replacement range from 3 to 4 days. After the first day, you will have two therapy sessions a day, one in the morning and one in the afternoon. The physical therapist will work with you on getting in/out of bed, walking, and they will initiate beginning exercises to help work on your knee motion and improving muscular strength.
For safety, initially you will start walking with an assistive device such as a walker. The social worker in the hospital will work with you on discharge planning and will be the one who manages what supplies you will need when you get home. The expected goals with physical therapy in the hospital are knee motion from 0 to 90 degrees and the ability to walk 300 feet safely.
After the hospital, you will receive home health physical therapy for approximately two weeks, which is scheduled by the social worker at the hospital. The physical therapist will come to your home and will continue to work with you on restoring knee range of motion and strengthening the muscles of your leg. The physical therapist will make sure you can safely move around your home using the walker and will help you progress to the point where you no longer require any assistive device with walking.
Usually two weeks from surgery the doctor will want you to come in for a follow up visit to check on the healing status of your knee. At this point the doctor will give you a prescription for physical therapy at an outpatient facility. Here at Back In Action Physical Therapy we will work with you and help get you back to what you love doing. Our physical therapists will see you 2 to 3 times a week and will work with you on further strengthening your knee and improve your ability to go up and down stairs, address any balance deficits and will work with you to restore your knee motion. Following a total knee replacement it is very important to start moving your knee in order to regain full function. The expected range of motion following a knee replacement is full extension and 125 to 135 degrees flexion or knee bend.