Knee prosthesis

When do I need an artificial knee joint?

The knee joint is a very complex joint. Disorders in this system, such as damaged joint cartilage or meniscus(menisci), promote the development of knee osteoarthritis, which is often very painful and leads to loss of movement.Advanced knee osteoarthritis (gonarthrosis) can often lead to the need for a knee prosthesis (partial or total joint prosthesis) if conservative treatment methods or arthroscopy have not successfully alleviated the symptoms.

Whether the use of an artificial knee joint is the right and necessary treatment method for you will be determined in a detailed examination. The implantation of a knee joint endoprosthesis (artificial knee joint) aims to restore freedom from pain as well as the ability to move and walk. However, an artificial joint can never completely replace the perfection of the natural joint. You must always be aware that it is an artificial joint which, depending on its mechanics, can make noises and also wear out the more you put weight on it. The doctor will explain the operation and the procedure to you in advance. He will also explain to you which type of knee prosthesis is to be used. However, the exact conditions in the joint will only become fully visible during the operation. It is therefore possible that deviations from the regularly discussed course of the operation may occur at this time.

Which method is best suited?

There are various methods available today, but soft tissue-orientated knee joint resurfacing has proved particularly successful in knee surgery. In this method, special attention is paid to the collateral ligaments of the affected knee. In contrast to the other methods, in which the computer or cutting templates are used to ensure that the axis of the thigh and lower leg are perpendicular (axis-orientated method), the soft tissue-orientated method uses a special soft tissue pressure gauge to determine the force of the inner and outer ligaments in the flexed and extended position during the operation. Scarred collateral ligaments are released until the affected knee is straight again when the same force is applied to the inner and outer ligaments. This makes it possible to customise the artificial knee joint surface replacement to the various disease-related changes in the knee joint. The surface replacement, which now forms the "new cartilage", is only inserted once the collateral ligaments have been equalised and the leg is straight. This ensures that the new, artificial knee joint surface replacement is evenly loaded.

The soft tissue-orientated method is used for the following procedures:

• Partial surface replacement (sled prosthesis, patellar gliding bearing replacement) : Only half of the joint surface needs to be replaced, while the cruciate ligaments are preserved
• Complete surface replacement (knee prosthesis): The entire joint must be replaced
• Revision prosthesis (coupled/guided knee prosthesis, total knee joint replacement): The collateral ligaments no longer function, the bone quality is poor (osteoporosis); in the case of significant malalignment or as a replacement for an existing prosthesis

What are the advantages of the soft tissue-orientated method?

The soft tissue-orientated approach, which focuses on the collateral ligaments, is gentler, less painful and promises better mobility and stability. There is also no need to donate blood before the operation. After the operation, the patient can immediately put weight on and move the operated knee again. Contact us here for a personal consultation.

Which knee prosthesis is the best?

The type of knee prosthesis best suited to the individual case is determined during the preliminary examinations. However, the exact conditions in the joint will only become fully visible during the operation. It is therefore possible that deviations from the regularly discussed surgical procedure may occur at this time.

Are there dentures for allergy sufferers?

Normal knee prostheses are made of stainless steel, an alloy consisting of a mixture of cobalt, chromium, molybdenum and nickel. Some people have a known allergy to these components or may develop one over time. To prevent this, we use body-compatible implants, so-called allergy prostheses, wherever possible. These are sprayed with titanium, among other things, which makes the surface of the artificial joint even smoother. This results in less wear and tear and better gliding of the artificial joint. In addition, the titanium coating prevents possible allergens, such as nickel, from being released from the metal. As a result, there is less irritation of the tissue, less pain and the artificial joint lasts longer. The components of the meniscus replacement (inlay) and the replacement of the back surface of the kneecap are made of plastic (ultra-high molecular weight polyethylene).

How can I prepare for the procedure?

There are a number of ways in which you can help to ensure that you get back on your feet quickly after the artificial knee joint has been fitted. Firstly, you need to be 100 per cent sure that now is the right time for an artificial knee joint.

Muscle building and exercise

It is important that you continue to strain and exercise your knee joints until the operation date, because the stronger your muscles and the better your mobility before the operation, the quicker you will be back on your feet. It takes three times longer to build up muscles than to break them down. Physiotherapy before the operation also provides positive support for the muscles. In addition, initial exercises can show you the best way to walk with walking sticks.

Strong immune system

Studies show that strengthening the immune system by adding vitamins and proteins before and after the operation is extremely important to minimise the complication rate. Well-tolerated nutritional supplements are used for this purpose. We also recommend cleaning the skin area to be operated on yourself shortly before the operation using appropriate disinfectant wipes and/or a special shower gel. This cleansing helps to reduce the risk of infection.

It is also important to have a check-up with your family doctor. Anaemia or other restrictions (e.g. circulatory problems, coagulation disorders, etc.) should be ruled out and treated if necessary before an operation. Being overweight or smoking is also unfavourable and should therefore be avoided or reduced.

Dental check-up

Before major joint replacement surgery, we recommend having your teeth checked by a dentist and restored if necessary. Dental hygiene (DH) is also recommended before the operation. After the operation, you should not go to the dentist or to the DH for at least 3 months in order to avoid possible infections.

How does a knee prosthesis operation work?

The procedure depends on whether it is a partial prosthesis, a complete replacement or a revision, but the surgical procedure is similar. First, the diseased bone and tissue parts are removed and the remaining bone is shaped so that the prosthesis parts fit exactly and can be fixed in place. We do not use a tourniquet for most of the time. The tourniquet is an inflatable cuff that is placed around the thigh and used to stop the blood flow in the leg. By not using the tourniquet, bleeding can be better controlled and the tissue protected. This improves wound healing and reduces the risk of infection. The tourniquet is only used when cementing the artificial joint to ensure optimum contact between the bone, cement and artificial joint.

What anaesthesia is needed for this?

We can offer knee surgery under general anaesthesia (general anaesthesia), regional or conduction anaesthesia (spinal or local anaesthesia) or a combination of these. You will discuss which anaesthesia is most suitable for you with the anaesthetist before the operation.

Risks and complications of the operations

Orthopaedic surgery has made great progress in recent decades. When performed by an experienced orthopaedic surgeon with years of training, knee operations are now routine procedures. The patient therefore has nothing to fear from an operation. Anaesthesia has also developed further and now enables very well-tolerated and safe anaesthesia, even for long operations.

Every operation harbours risks. These include general complications such as: Infections, wound healing disorders, haematoma and post-operative bleeding, thrombosis, injury to nerves, vessels or other anatomical structures, adhesions, excessive formation of scar tissue with reduced mobility and function of the knee joint and residual pain. Special complications such as bone fractures, allergies, increased osteoarthritis behind the kneecap, non-optimal positioning of the artificial components, incorrect guidance of the kneecaps, etc. will be discussed with you during a detailed consultation.

The risks are low for an initial operation, but then increase with each subsequent knee operation. A complication may mean that you have to have another operation. In a good clinic, you will be closely monitored so that a rapid response can be made in the event of complications.

How long does the hospitalisation last and what happens afterwards?

The average stay in the clinic is one week. Exercise therapy and daily exercises begin on the very first day after the operation. On around the fourth day, you will be able to take a few steps independently with crutches. The operated leg can be fully loaded if the pain and swelling allow it. During the first four to six weeks, the walking sticks are mainly needed for your safety and to train your gait. Pain-relieving medication is taken for as long as you are in pain. Thrombosis prophylaxis is necessary for six weeks, and the stitches are removed just under two weeks after the operation.

Regular follow-up checks at our centre allow us to monitor the healing process and, if desired, to give you behavioural recommendations or other supportive therapy tips (e.g. massages).

Sports activities or hobbies such as skiing or golfing can also be resumed with an artificial knee joint. It is important to build up the muscles.

What does rehabilitation at home look like?

Physiotherapy lasting several weeks should follow immediately after hospitalisation. Most patients organise themselves so that they can come to our physiotherapy two to three times a week. Of course, you can also look for a therapist near your place of residence. We are happy to issue appropriate prescriptions. Some health insurance companies also cover inpatient rehabilitation or a cure. This should be clarified in advance and then planned. If help with household chores is desired or necessary, this can be organised through Spitex. We will be happy to help you with the organisation.

How long does a knee prosthesis last?

Even if you want your new knee to last a lifetime, you need to be aware that an artificial knee joint is always a temporary solution: not because of the prosthesis itself, but because the ageing process continues and can have a significant impact on the stability of the artificial joint. Today, the average lifespan of a prosthesis is assumed to be at least ten to fifteen years. It is true that patients who have already received an artificial knee joint at a young age must expect to have another replacement or revision operation later in life. However, in view of the remarkable progress in both surgical techniques and the development of new artificial joints, this is very possible. The lifespan of an artificial knee joint can be negatively influenced by many factors. These ultimately lead to loosening of the artificial knee joint, resulting in increasing pain on exertion and gait instability. At an advanced stage, this requires a revision of the prosthesis.

Loading

Mechanical causes that have a negative impact on the service life of an artificial joint are increased stress on the joint and deterioration of the original anchoring of the joint in the bone. The joint's own activity plays a decisive role in overloading the joint. The more active and, above all, the more joint-straining sports you do, the more strain is placed on the anchoring of the lower leg component of the artificial joint. Overloading can also occur if the artificial joint is not optimally positioned. Furthermore, the original anchoring of the artificial knee joint in the bone can slowly deteriorate due to an increase in osteoporosis or quickly deteriorate due to a bone fracture caused by a fall. Both lead to loosening of the artificial knee joint.

Infections

These lead to activation of the immune system with inflammation and weakening of the anchorage. Infections can threaten the artificial knee joint throughout its life. Bacteria can enter the bloodstream via wounds to the skin or mucous membrane, lung or bladder infections, etc. and settle on the artificial knee joint. There they multiply and lead to an infection. The insidious thing about this is that such an infection is often only noticed after a long period of time. It manifests itself primarily through severe pain and swelling.

Allergies

An allergy can develop over the course of a lifetime: The immune system defends itself against the foreign material, which consists of stainless steel (nickel, chromium, cobalt and molybdenum), or its bone glue (cement). This leads to a non-infectious inflammation of the artificial joint, resulting in loosening of the joint.

Newly occurring stress and movement pain in the artificial knee joint that does not subside after a short time should definitely be clarified by an experienced knee specialist.

Living with a knee prosthesis

Basically, after the operation and subsequent rehabilitation, you should not only be free of symptoms, but also be able to continue more or less with the life you are used to and love. This includes social and sporting activities. Once you are well acclimatised to the new joint, increase your training again moderately and don't take too many risks, all types of sport should be possible again. Of course, sports such as skiing, snowboarding, football, tennis (stop-and-go, contact sports, etc.) are more dangerous and therefore less suitable than gentler sports such as swimming, cycling, hiking, etc.

However, special care should be taken when visiting the dentist. We have a lot of bacteria in our mouths that do not normally cause any problems. However, if the mucous membrane is damaged or if there are bad teeth (decayed teeth) that develop into a pus tooth, oral bacteria can enter the bloodstream. These weaken the immune system and can also be deposited and multiply in the artificial knee joint postoperatively. This can trigger an infection in the artificial knee joint. An infection of the artificial knee joint caused in this way is rare, but can result in serious complications for the person affected. The infected artificial joint must be operated on again and recovery supported by a long course of antibiotics. If the treatment does not work, the artificial knee joint has to be completely removed and a new knee prosthesis has to be fitted at a later date once the joint infection has healed. This is very stressful for the psyche and the body. In addition, the result of such an artificial joint is usually worse, with more pain and less mobility. Good oral and dental hygiene is therefore highly recommended.

In the event of an emergency or a surgical procedure in general, antibiotic prophylaxis should be considered for the treatment, depending on the patient's condition (immunosuppression, diabetes mellitus, etc.) and the type and duration of the procedure. The doctor should be informed that you have an artificial joint.

Costs and assumption of costs

The cost of knee surgery depends on various factors, mainly the duration and complexity of the procedure and the amount of material to be implanted. As a rule, your health insurance will cover the full costs, provided you have the appropriate insurance. For the Pyramid Clinic, you will need supplementary private or semi-private insurance.

Whether a subsequent rehabilitation stay will also be covered by the health insurance company must ideally be clarified with the insurance company before the operation.

If you wish to finance the operation yourself, we will be happy to put together a cost estimate on request and after a thorough examination. This also applies in particular to foreign patients.

Book a consultation appointment

We guarantee rapid, expert clarification and advice as well as treatment using the most modern methods.

Dr Andreas L. Oberholzer is a recognised expert in knee problems and has extensive experience in the field of artificial knee joints.

Book your appointment directly online here or call us on +41 44 388 16 16. You are also welcome to come to us for a second opinion.