Orthopaedic implants are made of alloys of cobalt-chrome and titanium that have been implanted in millions of patients over the past three decades. Allergies to solid metal alloys are sometimes speculated, but are rarely seen in practice. Most instances of a painful knee after replacement have to do with a problem related to the surgery, or possibly an infection. A true metal allergy is extremely rare, and seldom encountered in clinical medicine.
Some patients report increased pain and stiffness, or can feel changes in the weather after knee surgery, especially with an artificial joint. These sensations are not common though, and usually will disappear over one to two years after surgery. For the first couple of years, the bone adapts and grows around the metal prosthesis, and this bone activity probably leads to increased sensitivity to weather and pressure changes that some patients can feel in their joints.
Because you have an artificial knee joint in place, you must take care to protect it from infection. The same applies to any artificial implant in your body. Before having dental work (teeth cleaning, fillings, extraction or root canals) or certain medical procedures (colonoscopy, biopsy, endoscopies, etc.), you must take an antibiotic.
The antibiotic will help prevent bacteria from getting into the blood stream and thus into your knee. The odds of this happening are very rare, but the antibiotic can reduce this already small risk.
For routine dental prophylaxis following knee replacement surgery, antibiotics are required for your lifetime after the surgery.
Cephalexin and amoxicillin are antibiotics commonly prescribed before and after dental work. You may take azithromycin or clindamycin if you are allergic to amoxicillin. You also may take any antibiotic recommended by the American Heart Association.
Antibiotics given for other medical procedures may vary. Contact us for advice if there is any doubt. Keep in mind that it will be necessary for you to be treated with a full course of antibiotics if you develop an infection such as an abscessed tooth, pneumonia, bronchitis, and skin or urinary infections.
If you cut your foot, or have broken skin on the leg, or infection in a toenail after a knee replacement, seek medical attention immediately. Ignoring a festering sore means that there is a risk the bacteria could migrate to the knee implant, resulting in a serious deep infection, even though it happens rarely.
Most likely, it will. Tell airport personnel that you have an artificial joint prior to entering the metal detector. Metal detection sensitivity at airports is highly variable, and it is impossible to say if a certain detector will set off the equipment. We will supply you with an implant identification card that you can carry to prove that you have metal knee replacement parts.
Yes. MRI scans of other parts of your body are safe after knee replacement. Although some old MRI scanning equipment may not be compatible with your prosthesis, the majority of MRI scanning equipment today is safe and compatible with knee replacement parts. You may also have a CT scan of any part of your body after a knee replacement.
In the extremely unlikely event of a recalled implant, you will be contacted by the company who made the device. All implants have lot numbers registered with the implant maker. This information is kept in your medical record. If you want a copy of your X-ray or exact implant type and model for your records, please let us know.
Rest assured that of the millions of artificial joints implanted each year, the incidence of recall is exceedingly rare. Implant companies monitor the performance of their products very carefully.
No, the implants are engineered to withstand your body weight and activity level, but the moving parts of a knee replacement do wear over a period of several decades. 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. This is why the skill and expertise with which the knee is implanted in your body is a critical determinant of how long the knee will last and how well it will perform.
With modern technology, cases that were considered hopeless a few years ago can undergo successful knee replacement surgery. Such complex knee replacements are done every week in our specialty practice, and are referred from all over. So, there is no hard and fast rule as to how many times a knee can be replaced. Knees that have had multiple operations may be missing structural bone support, muscle cover, and quadriceps support.
While we hope that you never need such complicated knee operations, it is possible to get patients mobile again in situations that would have resulted in an amputation in the past. This reflects advances in surgery techniques and related technology.
Please use this website as your reference. This information was written by Dr. Bal, specifically for our patients and the operations that he performs. If there is ever a question or conflict in your mind, email Dr. Bal or any of our staff.
Please email or call us. Every member of our team is experienced and knowledgeable. Knee and hip replacements are our specialty and we keep up with the latest technology, innovations, and research. Many of the questions in this book were raised by patients like you, and we may include your comments or questions, with your permission.