Welcome to Hicksville Physical Therapy’s patient resource about Artificial Joint Replacement of the Knee.
People today are living longer than ever, and that means more people with severe joint pain that gets in the way of living an active lifestyle. Fortunately, because of significant progress in the medical field, the artificial knee replacement surgery or arthroplasty is becoming much more widely accepted as a safe and effective treatment option for joint pain in the knee.
This article will help you understand:
Understanding the anatomy of a healthy knee
Where the thighbone or femur attaches to the shinbone or tibia is what’s known as the knee joint. A smooth and slippery coating of articular cartilage coats the tips of these two bones where they meet as to limit friction that could damage the joint. This cartilage is lubricated by a fluid made in the joint lining or synovial membrane and stored in an enclosed sack near the joint called the joint capsule.
In front of the femur and tibia’s meeting point is the kneecap, also known as the patella. The patella is surrounded by a connecting tendon that attaches the quadriceps muscles on the front of the thigh to the lower leg bone, and is backed by a layer of articular cartilage that allows it to glide against the femur without causing damage.
What are the reasons for undergoing an arthroplasty?
Reducing painful friction of an arthritic joint is the primary reason why a person would want to undergo an artificial knee replacement surgery. When the effected joint is replaced with an artificial prosthesis, the joint is given a fresh surface in which its components can glide against one another without discomfort. This is the goal of an arthroplasty – helping people get back to living an active lifestyle with decreased pain and regained independence.
How should I prepare for knee replacement surgery?
Although you are responsible for making the final decision as to whether or not to undergo a joint replacement surgery of any kind, it’s important that you talk openly with your doctor about possible complications as well as alternative treatment options. Regardless of your decision, it’s crucial that you and your doctor are on the same page.
If you do make the decision to undergo a surgical procedure, you should expect several things to happen first. For starters, you will most likely be recommended for a total physical examination by your primary care physician prior to surgery. In addition you may be required to take part in several preoperative sessions with a physical therapist, specifically the physical therapist that will be monitoring your recovery post-operation. This is not only to ensure that both your surgical team and physical therapist have a recorded baseline of information regarding your joints’ health and abilities, but also so you can become familiar with your recovery process before you undergo the procedure.
Already having knowledge of your recovery process will provide you with peace of mind both going into surgery and afterwards. During these preoperative sessions with a physical therapist, you will trained in using assistive devices such as a walker or crutches, as well as in several of the exercises you will be required to do nearly every day during recovery. Based on these sessions, your team of physicians will prepare your home for your release from the hospital with any necessary equipment or modifications.
For the possibility that you may need to undergo a blood transfusion during the operation, you could be asked to provide a blood donation three to five weeks before the surgery date. This will leave enough time for your body to create new blood cells to replace what was taken during the blood work.
What happens during the procedure?
To fully understand how an artificial knee replacement surgery is done, let’s first gain an understanding of the artificial knee prosthesis.
The Artificial Knee
There are two primary kinds of artificial knee replacements:
Both the cemented prosthesis and uncemented prosthesis are widely used, and in some cases you will be recommended a prosthesis that combines both materials. Which type of prosthesis you are given will usually be decided by your surgeon and be based on several factors including your age, lifestyle, severity of the joint pain, as well as the surgeon’s medical training.
Both types of prosthesis are made up of three primary parts.
The bottom portion is known as the tibial component, and takes the place of the lower bone’s upper surface while the top portion, known as the femoral component, takes the place of the bottom surface of the upper bone, also known as the femur. Lastly, the patellar component or kneecap portion of the prosthesis takes the place of the patella’s surface where it makes contact with the femur.
Whereas the femoral component is made from metal, the tibial and patellar components typically include a strong plastic material. In most cases, tibial component has both a metal tray directly attached to the bone and a plastic spacer that offers a smooth surface to prevent against damaging friction. The patellar component is also usually made entirely of plastic however some versions of the prosthesis include a combination of both metal and plastic.
The cemented prosthesis would be secured using an epoxy cement that would fuse the metal to the bone. The uncemented prosthesis would have be made with a fine mesh of small holes covering the surface so that the bone could grow into the mesh and attach itself to the prosthesis without the need for any cement or other glue-like material.
The first step in the procedure is to make a small incision in the front of the knee that will act allow full accessibility to the joint. How the incision is made is based on the surgeon’s own experience and training. You should feel comfortable asking your surgeon for the specifics of the procedure.
Once the knee joint is opened, a special positioning device (a cutting guide) is placed on the end of the femur.
A cutting guide (a surgical positioning device) will be attached to the end of the femur once the incision is made on the knee joint. This cutting guide will help to make sure that the bone being operated on is cut properly in relation to the leg’s natural angles. This is especially important in procedures for arthritic patients who have become bowlegged or knock-kneed as a result of the disease.
The metal knee prosthesis will replace the several pieces of bone removed from the end of the femur. Next, the tibia or shinbone’s surface is prepared using a different cutting guide.
The patella’s artificial surface is then taken away.
With an uncemented prosthesis, the metal femoral component is joint with the femur very tightly as a result of the femur being shaped for the addition of the prosthesis. The metal component is attached to the upper end of the femur and held in place by use of friction. However with a cemented prosthesis, a strong cement made from epoxy or a similar material is used to join the prosthesis and the bone.
The metal tray responsible for holding the plastic spacer in place is cemented or in some cases screwed to the upper portion of the tibia. As mentioned above, the prosthesis contains a mesh-like surface of small holes in which the bone can grow into. For this reason the screws would only be used to hold the tibial tray in place until that happens, however the screws would not be removed.
The plastic spacer is joint with the tibial component’s metal tray in a way that would allow it to be replaced in the future if it becomes worn out. This procedure to replace the tibial component is known as a retread. The patellar component is then sized accordingly and attached to the prosthesis in back of the patella, usually by means of an epoxy cement.
Lastly, the surgeon will stitch up the soft tissues and use steps to hold the incision together, as is the case with other surgical incisions.
Possible Complications of the Procedure
Complications are unfortunately a very real possibility of any surgical procedure that patients must be made aware of. Although not a complete list, the following complications are the most common for procedures like an artificial knee replacement:
Complications from Anesthesia
In most cases of surgery procedures like a artificial knee replacement, some form of anesthesia is required. However, although uncommon, some people respond poorly to anesthesia due to other medical complications. It’s important that you take the time to learn about the risks of anesthesia and voice your concerns with your surgeon and anesthesiologist.
Thrombophlebitis (Blood Clots)
Deep venous thrombosis, also known as thrombophlebitis or DVT is a rare but very possible occurrence after a surgical procedure of any kind in which blood clots form in the leg’s larger veins, causing swelling and overall discomfort and pain. Although uncommon, it is more likely to occur after surgeries of the hip, pelvis, or knee. What makes DVT especially severe is that in the case blood clots break apart, they can move towards the lung and become lodged inside the capillaries where they cut off the lung’s blood supply – a condition known pulmonary embolism.
Luckily there are several measures doctors will recommend after surgery as to prevent DVT including the addition of pressure stockings that keep blood in the legs from pooling up in one spot, as well as blood-thinning medications that prevents clots from forming. However the most effective way to prevent this condition is to get moving after surgery as soon as it is safe.
Although the chance of your artificial knee replacement procedure leading to an infection is rare, around one percent to be exact, it is still a very real and serious possibility. Therefore it’s important to become familiar with the warning signs so you can treat the infection before it spreads. While some infections may show up immediately after surgery before you’re even released, other infections will not show signs for months or even years. It’s also important to keep in mind that an infection may show up in areas of the body far from where the procedure took place. Likewise an artificial joint can become infected from other unrelated medical procedure such as bladder or colon surgeries, or even dental work. For this reason your surgeon may recommend that you take antibiodics after these procedures.
During a knee replacement procedure, the surgeon will aim to position the knee in the best possible alignment so as to distribute tension equal among the various ligaments and soft tissues. This is known as balancing and it is the single most important factor in determining the leg’s range of motion post-operation.
Although uncommon, some patients will not be able to return to their normal range of motion after a knee replacement surgery due to additional scar tissue developing that could lead to increased stiffness in the joint. In this scenario, you may be recommended for another surgery to regain motion without damaging the joint.
Note that 90 degrees is the necessary range of motion in order to rise from a chair, while 110 degrees is an optimal range of motion overall.
Although advancements in the medical field have seen an extended lifespan of artificial joints, it’s unlikely that your knee prosthesis will last longer than 12 to 15 years. However loosening of the metal or cement components from the bone may occur even earlier, causing pain and requiring you to undergo a revision surgery.
What to expect post-operation
While a regular exercise regimen monitored by your doctor or physical therapist will greatly help with restoring your knee’s range of motion post-operation, a continuous passive motion (CPM) machine may also be recommended. It is essentially an orthopaedic device that will help to prevent blood clots as well as accelerate the healing process around the incision. A CPM may also take the place of additional medications, however this is all depending on your specific recovery process.
Physical therapy treatments to improve the knee’s range of motion will most likely be required once or twice a day while in the hospital, and usually continue after your release. These sessions will involve gentle movements such as bending, straightening, and elevating the leg to help drain excess fluid as to prevent clotting. Exercises to target the thigh and hip muscles will also be a part of your treatment, as well as ankle movements to help ease any swelling of the leg. Once you are stable enough to stand, your physical therapist will guide you on a short walk using crutches, a walker, or another assistive mobility device. If you have been given a CPM device, its alignment and settings will be checked over during these sessions as well.
Once you are able to safely perform regular tasks like getting in and out of bed, walking approximately 75 feet with an assistive device, going up and down stairs, and using the bathroom without assistance, you will be released from the hospital. It’s also necessary that you obtain the ability to fully contract the quadriceps as well as perform an improved range of motion in your knee. This usually takes around two to four days after the procedure. But it’s important to not rush your release. If needed, you may be sent to another care unit before being sent home.
Regular checkups will most definitely be a required part of your recovery, however how often these checkups occur will depend on your surgeon’s recommendations. Some patients will be recommended for a checkup ever five years, while some every couple of months. It’s important to be honest with your orthopaedic surgeon if you think that there is a malfunction in your artificial knee replacement.
While not common, you may experience a period of pain after your knee replacement surgery that lasts longer than a few weeks, in which case you should reach out to your surgeon. An examination of the knee including X-rays will most likely be taken in order to identify any signs of loosening.
What should I expect during my rehabilitation?
At Hicksville Physical Therapy’s rehabilitation program, you should expect our physical therapist to use either heat, ice, electrical stimulation, or a combination of these to help in reducing any discomfort or swelling that may occur.
If you were given a cemented prosthesis, you will be directed to gradually increase the weight you place onto your leg that was operated on. However, if you were given an uncemented prosthesis, you will be directed to wait approximately five or six weeks to put pressure on the leg. Until that time, you should only be placing pressure on the toes. It’s important to continue using a walker or crutches until your doctor tells you that you’re ready to walk without any assistance.
At first, our physical therapists will use primarily hands-on stretching motions to aid your recovery, with strength training added after to target specific muscle groups like the buttock, hip, calf, and thigh muscles. Later on in recovery you may be able to use swimming as a way of building up strength. This is a great way to perform therapeutic exercises without putting too much stress on the knee joint on account of the buoyancy. Once you become fluent in your pool exercises you may be given an independent program. Other endurance exercises may include stationary biking or an upper cycle called an upper body ergometer.
Once you’re able to apply full weight to your leg, your Hicksville physical therapist will create an exercise plan made just for you to help you improve your ability to stabilize and move the knee as well as improve your balance overall.
These exercises are tailored to your specific recovery process in order to stimulate additional activities that you’ll need to be able to perform when released back home. It’s important to discuss your work and hobbies with your physical therapist as additional exercises may be required to allow you to return to these activities.
Adjusting your habits and activity choices may be necessary in order to refrain from putting too much stress on your artificial knee replacement. While activities such as swimming, level walking, bowling, golfing, and cycling are encouraged as they are relatively low impact activities, more intensive sports that involve running and jumping are discouraged. If you follow your physical therapist and surgeon’s guidelines, you will most likely have a speedy recovery that comes with improved mobility.
At Hicksville Physical Therapy, our goal is to help you improve knee range of motion, maximize strength, and improve your ability to do your activities. When your recovery is well under way, regular visits to our office will end. Although we will continue to be a resource, you will be in charge of doing your exercises as part of an ongoing home program.
Hicksville Physical Therapy offers physical therapy services in Hicksville, New York. Our mission is to help you improve your knee’s range of motion, strength, as well as restore your independence in doing the activities you love. Once you are far along your recovery, you will no longer be required to regularly visit our office and will be in charge of performing your own exercises at home. However our physical therapists will continue to be a useful resource for you if you have any questions or concerns.