Here you will find concise answers to the most frequently asked questions about your knee operation. Feel free to contact us personally – we are here for you!
What material is the prosthesis made of?
Knee prostheses are made of medical steel, a compound of nickel, cobalt and chromium. This
is one of the hardest metals and therefore has the best wear properties. Titanium alone is too soft a material for knee prostheses and would cause too much wear. A polyethylene part (called an inlay) is inserted between the metals as a sliding surface. This inlay replaces the menisci and cartilage of the natural knee joint.
Are there allergies to prostheses?
A contact allergy of the skin to nickel, cobalt or chromium does not automatically mean an allergy to the prosthesis. On the one hand, the proportion of nickel in the prosthesis material is extremely low, and on the other hand, the immune processes in the joint are different from those on the skin. We have been using standard prostheses in allergy patients for years and have had very good experiences with them. In particular, the cementless prostheses used have a titanium surface on the bone side, which reduces the risk of allergies. According to scientific studies, special allergy prostheses have an increased complication rate and increased wear, which is why we do not use them.
What are the risks and complications of a knee prosthesis?
As with any operation, complications can occur with a knee prosthesis. The risk of complications depends in particular on the patient’s secondary conditions. These include, in particular, wound healing disorders, infections, thromboses, secondary bleeding, injuries to surrounding structures, bone fractures around the prosthesis, loosening of the implants and malfunctions of the artificial joint. Your specialist will provide you with comprehensive information about possible risks.
Is the prosthesis cemented?
Both cemented and cementless prostheses are available for initial implantation.
According to current knowledge, there is no significant difference in the longevity of the prosthesis. Since only very little cement is used, cementing does not mean any disadvantage for a later replacement of the prosthesis. We make the decision depending on your bone quality and the prosthesis model used. We use cementless total prostheses in around 90% of cases. Not every prosthesis is available as a cementless version. The coupled prostheses are always cemented, at least on the bone surface.
Will my kneecap also be replaced?
According to current studies, there are no relevant differences in patient satisfaction and the risk of complications with or without patella replacement. However, we have found that, particularly in very active patients or with certain knee anatomies, there can be increased patellar pain in the long term after knee replacement. This occurs much less frequently if the kneecap is also replaced during the operation. Accordingly, it is our standard procedure today to also replace the kneecap during a total knee replacement (only the back surface is replaced anyway). Unless there are reasons (e.g. poor bone quality) that speak against it.
Will I get a straight leg after the operation?
The aim of modern knee prosthetics is to restore your individual leg axis before osteoarthritis with the knee prosthesis. So if you have always had a slight bow leg, the prosthesis is used to reconstruct it. Existing deformities (e.g. pronounced knock-knees), on the other hand, are corrected and straightened.
How long will the prosthesis last?
According to current data in prosthesis registers, we see that around 85% of prostheses are still functional after 25 years. Of course, this depends on various factors. Young and active patients must expect slightly higher wear. In particular, improved polyethylenes, the sliding surface of the prostheses, have reduced the wear of prostheses in recent years.
Can I do sports with a knee prosthesis?
In principle, you can also do sport with a knee prosthesis. However, patients often report some pain during these activities. Others can no longer achieve their desired level of activity with a prosthesis, so this is to be expected. Sports with high impact loads, such as jogging, should be avoided as this can lead to premature loosening or wear of the prosthesis. In the event of an accident or fall, bone fractures may occur around the prosthesis, which may require the prosthesis to be replaced. A possible tear in the inner ligament also has fatal consequences for the prosthesis, as this makes it necessary to replace the prosthesis with more guidance through the prosthesis (so-called coupled joint). For this reason, no unnecessary risks should be taken during sport. Recommended sports are cycling, which can usually be resumed after 2-3 months, or swimming. When hiking or walking, especially downhill, poles are recommended as an aid.
What quality monitoring is there?
In Switzerland, all implanted prostheses have been entered in a register and monitored since 2012. Complications and reoperations are also recorded. This gives us a high level of patient safety, as problems with certain prosthesis models can be identified at an early stage. The articon practice also carries out its own check-ups in order to precisely record quality and react to problems at an early stage.
How long will I be unable to work?
The period of incapacity for work depends on your profession. For office jobs it is 4-8 weeks, for standing jobs 8 weeks and more. In physically demanding occupations, it is sometimes only possible to return to work after 3-6 months
.
When will I be allowed to drive again?
You can drive as soon as you can put full weight on your knee and move it without significant pain. This is usually possible after 4-6 weeks with knee prostheses. If your left leg has been operated on and you are driving a car, you can drive again straight away.
Do I have to take antibiotics antibiotics before dental treatment?
Theoretically, there is a lifelong risk of infection with a prosthesis if bacteria enter the bloodstream, such as during dental surgery. In reality, this is an extremely rare complication that also depends on how long ago the procedure was performed. The official recommendation is not to have any dental treatment (including dental hygiene) carried out in the first 3 months after prosthesis implantation. If treatment cannot be avoided, a one-off antibiotic prophylaxis should be carried out. After 3 months, special protection is no longer necessary from the prosthesis’ point of view.
If your concerns have not been fully clarified here or if you have any further questions, please do not hesitate to contact us – we will be happy to assist you.