During knee replacement surgery, the surgeon surgically removes the damaged bone and cartilage of the joint and replaces it with smooth, artificial implants - thereby eliminating painful bone-on-bone contact.
Almost all knee replacement implants consist of a four-part system:
The tibial (shin) side has two elements and replaces the top of the shin bone. This portion of the implant is made up of a metal tray attached directly to the bone and a plastic spacer that provides the lower half of the new joint's bearing surface.
The femoral (thigh bone) side is a single element that replaces the bottom of the thigh bone and provides the top half of the new joint's bearing surface. This component also replaces the groove where the patella, or kneecap, sits.
Finally, the patellar component replaces the surface of the kneecap, which rubs against the femur. The patella protects the joint, and the newly resurfaced patellar button will slide smoothly on the front of the joint.
Am I A Candidate - Knee Replacement
Total knee replacement surgery is considered when all other conservative measures have failed to provide successful intervention, and may be performed for the following reasons:
- To relieve pain
- To improve joint stability
- To improve alignment and correct bone deformity
- To maximize quality of life
- To optimize activities of daily living
People who benefit from total knee replacement surgery often have:
- Knee pain that limits everyday activities, such as walking or bending
- Knee pain that continues while resting, either day or night
- Stiffness in a knee that limits the ability to move or bend the leg
- Inadequate pain relief from anti-inflammatory drugs, physical therapy, or walking supports
What is the Right Age for Total Knee Surgery?
There are no absolute age restrictions for total knee replacements.
Recommendations for surgery are based on a patient's pain and disability, not age. Most patients who undergo total knee replacement are age 50 to 801, but orthopaedic surgeons evaluate patients individually. Total knee replacements have been performed successfully at all ages.
Once you and your orthopaedic surgeon have decided to proceed with surgery, there are several activities that must occur prior to surgery, including the following:
Initial Surgical Consultation
Preoperative x-rays, complete past medical history, complete past surgical history, complete list of all medications and allergies (prescription, over-the-counter, vitamin supplements).
Complete Physical Examination
Your internist or family physician will determine if you are in the best possible condition to undergo surgery.
A transfusion may be necessary after surgery, therefore you may wish to donate blood prior to surgery.
Instructions for an exercise program to begin prior to surgery and an overview of the rehabilitation process after surgery will better prepare you for post-operative care.
Preparation for the Hospital
You may want to bring the following items:
- Clothing: underwear, socks, t-shirts, exercise shorts for rehabilitation
- Footwear: walking or tennis shoes for rehab; slippers for hospital room
- Walking Aids: walker, cane, wheelchair, or crutches if used prior to surgery
- Insurance Information
Evening Before Surgery
Do not eat or drink after midnight. Shower (with five minute scrub to surgical area with special soap provided). Prepare your belongings and review your knee replacement booklet.
Day of surgery
This section will give you a brief overview of the activities that will occur on the day of surgery:
- You will be admitted to the hospital, typically the morning of your surgery.
- A final assessment of vital signs will be taken.
- A clean hospital gown will be provided.
- An IV will be started to give you fluids and medication during and after the procedure.
- An elastic stocking may be provided to decrease the likelihood of blood clots.
- You will be asked to empty your bladder.
- All jewelry, dentures, contacts, and nail polish must be removed.
- The surgical leg will be scrubbed and shaved in preparation for surgery.
- The anesthesiologist will discuss the type of anesthesia that will be used.
- You will be taken into the operating room.
Knee Replacement Procedure
Knee replacement surgery typically takes between one and two hours to complete. This section will provide you with a brief, easy-to-understand description of the surgical procedure:
- An incision is made extending from the thigh, past the inside edge of the kneecap, and down to the shinbone.
- The end of the femur is shaped in preparation for sizing the femoral trial component.
- The top of the tibia is shaped for proper sizing of the tibial trial component.
- The trial units are put in place and the appropriate implant size is selected.
- The knee is assessed for alignment, stability, and range of motion.
- The underside of the kneecap is prepared and patella trial is selected.
- The trial units are removed and the final femoral, tibial, and patella components are implanted.
- The incision is closed, a drain is put in, and the post-operative bandaging is applied.
Postoperative Care / Rehabilitation for Knee Replacement Surgery
After your surgery is completed, you will be transported to the recovery room for close observation of your vital signs, circulation, and sensation in your legs and feet. As soon as you awaken and your condition is stabilized, you will be transferred to your room. Below is an example of what you may see when you wake up:
- You will find a large dressing applied to your incision in order to maintain cleanliness and absorb any fluid.
- There may be a drain placed near your incision in order to record the amount of drainage being lost from the wound.
- You may be wearing elastic hose, and/or a compression stocking sleeve designed to minimize the risks of blood clots.
- Your doctor may prescribe a PCA (patient-controlled analgesia) that is connected to your IV. The unit is set to deliver a small, controlled flow of pain medication and is enacted when you firmly press the button on your machine. Press the button anytime you are having pain.
- You may have a catheter inserted into your bladder as the side effects of anesthesia often make it difficult to urinate.
- A continuous passive motion (CPM) unit may be placed on your leg to slowly and gently bend and straighten your knee. This device is important for quickly regaining your knee range of motion.
- When your leg is not in the CPM, you may be wearing a knee immobilizer to protect your knee when you stand up.
The JOURNEY◊ II Knee
Recent advances in biomedical engineering software have opened a new chapter on high performance knee implants. One breakthrough has been the creation of the JOURNEY knee, a first of-its-kind knee replacement that combines the stability and natural motion of the human knee with new low-friction materials that may extend the life of the implant. While the lifespan of a knee implant is heavily influenced by the materials used to make it, the natural feeling of the implant during physical activity is dependent upon the way the patient’s muscles, ligaments and tendons are addressed during surgery and by the implant’s shape within the body after surgery.
The knee is a hinge joint, but it does not swing like a simple door hinge. It has a complex rotational motion that you don’t notice is there—but many patients know when it’s not there after total knee replacement. Traditional implants attempt to recreate this subtle swing-and-rotate action with either a rotating platform (a simple pivot point) within the implant or by requiring an angled alignment of the implant during surgery.
With these traditional knee replacement designs, the muscles and ligaments around your new joint have to work harder because the implant’s slightly unnatural shapes and resulting motion make these soft tissues move in unfamiliar, stressful ways. This leads to joint pain, muscle fatigue and the unnatural feeling patients experience while walking or bending in the months after their procedure.
The JOURNEY knee, on the other hand, is the only knee implant designed to reproduce the original internal shapes and angled forces of the human knee. through its full range of motion—accommodating the swing-and-rotate of the joint with the same engineering principles your real knee currently uses. Because of this, your soft tissues don’t have to readjust to new shapes and forces after surgery and your stride can return to its natural rhythm.
The JOURNEY knee also reproduces the stability provided by your anterior cruciate ligament (ACL) and your posterior cruciate ligament (PCL). Your ACL and PCL are key to the stability of your real joint and contribute to natural motion when your knee is fully extended and fully bent. No other knee implant reproduces both functions.
The information listed on this site is for informational and educational purposes and is not meant as medical advice. Every patient's case is unique and each patient should follow his or her doctor's specific instructions. Please discuss nutrition, medication and treatment options with your doctor to make sure you are getting the proper care for your particular situation.The information on this site does not replace your doctor's specific instructions.
The Oxinium Advantage
More than a decade ago, Smith & Nephew introduced OXINIUM◊ Oxidized Zirconium. This patented metal alloy is available for many of our knee and hip implant systems. The combination of hardness, smoothness and scratch-resistance makes it a superb choice for hip and knee implants.
OXINIUM material—a metal alloy with the surface transformed to ceramic using a patented process—has proven to be a superior metal for use in hip and knee implants due to its reduced friction and increased resistance to scratching and abrasion. These superior properties result in significantly less wear than can be produced by cobalt-chrome alloy (historically the material of choice in hip and knee implants).
Some facts that may interest you:
- OXINIUM material has a surface hardness that is over twice that of cobalt-chrome
- OXINIUM material may last longer than other implants as it reduces more than half of the implant wear common to other knees and hips based on lab simulator studies
- OXINIUM material avoids the risk of brittle fracture that can occur with ceramic implants
- OXINIUM material is 20% lighter than cobalt-chrome
- OXINIUM material contains <0.0035% for detectable nickel, the leading cause of negative reactions in patients with metal sensitivities