X-ray of total knee replacement, anterior-posterior front to back view.
May 20, Total knee replacement surgery Total knee replacement consists of three main components: The following model shows the components of a knee replacement. The model on the left shows the front view and the model on the right shows the side view.
There are several types of full knee replacements that are available to your surgeon. The decision for the type of knee replacement to be used may be based on several factors.
One way of categorizing knee replacement components involves whether the plastic polyethylene is fixed securely upon the underlying tibial component or whether it allows rotation upon the tibial component.
These are respectively referred to as fixed bearing versus rotating platform RP knees. Tap on the below image to show how a rotating platform knee allows rotation of the plastic in relation to the tibia. Click on the below image to show how a rotating platform knee allows rotation of the plastic in relation to the tibia.
There are theoretical advantages to allowing the plastic to rotate upon its tibial base plate. This type of prosthesis helps replicate the small amount of rotation that a normal knee experiences when becoming fully extended.
Another advantage is that there may be less shear stress on the top of the plastic, where the femoral component bends.
There are potential disadvantages to this type of prosthesis. Rotating platform RP knees are more depended on the surrounding ligaments and soft tissues ligaments and soft tissues to prevent dislocation.
They are also more prone to soft tissue impingement.
Sometimes, RP knees are recommended for younger and more active patients more active patients. Long term studies show similar survivorship of RP knees compared to fixed bearing knees. Another category relates to how the posterior cruciate ligament is treated during surgery. Some surgeons routinely remove the posterior cruciate ligament and will use posterior stabilized PS components.
If the posterior cruciate ligament is in good condition, some surgeons will retain this ligament and use cruciate retaining CR components.
There are advantages to using each type of prosthesis. PS knees allow for the reliable restoration of knee kinematics, small improvements in motion compared to CR knees, and the theoretical reduction in polyethylene wear. PS knees are specifically indicated in patients with severe deformity, severe flexion contracture, previous removal of the knee cap, and during revision surgery.
When looking at an x-ray, there are defining characteristics that can be used to identify whether a posterior cruciate substituting PS or cruciate retaining CR knee was implanted. On the side view of the x-ray, the difference can be seen on the metal component on the thigh bone femur.
Look at the following example: The red arrow points to CR knee. Notice how the CR knee requires less bone to be removed. The last category has to do with how the metal components are fixed to the underlying bone. Most replacement systems use a special type of cement called methylmethacrylate to bond the metal component to the bones.
This cement sets up in approximately 13 minutes during the surgery and allows the patient to walk without restricting the amount of weight bearing after the procedure. Use of these techniques may also allow the patient to progress to immediate weight bearing.
Additionally, most surgeons in the United States will also resurface the underside of the knee cap. This is done with a plastic button. However, it is common for surgeons in the United Kingdom to not resurface the knee cap. There is slightly more anterior knee pain anterior knee pain associated with not resurfacing the knee cap, but lowers the small risk of complications from the resurfacing procedure.Choosing a Knee Implant / Prosthesis 34 Shares Share 1 Tweet 1 Share 1 Email 31 One of the most important things you will want to discuss with your chosen knee surgeon is the type of knee replacement prosthesis he or she will be implanting.
Hip replacement is a surgical procedure in which the hip joint is replaced by a prosthetic implant, that is, a hip caninariojana.com replacement surgery can be performed as a total replacement or a hemi (half) replacement.
Such joint replacement orthopaedic surgery is generally conducted to relieve arthritis pain or in some hip fractures.A total hip replacement (total hip arthroplasty) consists.
You've heard the story a dozen times in a dozen different ways. Peter Benjamin Parker is an awkward and introverted science nerd and high-school student who was bitten by a genetically augmented spider during a tour of the OsCorp labs. Imbued with the ability to do most of "whatever a spider can," and giving himself the artificial ability to spin webs with wrist-mounted web-shooters and.
A properly aligned knee replacement done by a competent, experienced surgeon will usually last the lifetime of most patients. Subtle component malpositioning and suboptimal orientation can however compromise the lifespan of the implant. Osteoarthritis, the cause of my wear and tear, is the most frequent reason for a hip replacement in Canada, a procedure that continues to evolve since it was first tried in the s.
Total knee replacement implants are not one-size-fits-all or even one-style-fits-all. Prosthetic implants vary greatly by design, fixation and materials.. Your implant may be a fixed- or mobile-bearing implant; a PCL-retaining design or a PCL-substituting style.