Total Joint Replacement: Knee Joint
Whenever we walk, stand, sit or squat, we move the largest joint in the body: the knee joint.
- Extensor muscles of the thigh
- Kneecap (patella)
- Thigh bone (femur)
- Meniscus (crescent-shaped wedge of fibrocartilage)
- Patella tendon
- Calf bone (fibula)
- Shin (tibia)
Non-surgical therapy: knee
Knee pains are very common. They often have fairly benign causes and may possibly only require brief, non-surgical treatment.
What has caused your pain?
Based on the mechanism of injury, the type of pain, the clinical examination, the X-ray examination and the MR imaging, we will determine the cause of your pain .
Patients with osteoarthritis , for example, can often be successfully treated non-surgically over many years. The goal is for you to feel good and for your range of motion and level of activity to be preserved.
The treatment options for non-surgical therapy include:
- Non-steroidal anti-inflammatory drugs (NSAID), which have an analgesic and anti-inflammatory effect
- Physiotherapeutic exercises that you perform independently at home and, if necessary, a change to your habitual activity
- Physical therapy
- Braces for the knee that help protect it
- Physiotherapy
- Injections with cortisone, plasma (PRP for short) or hyaluronic acid
I also assess your range of motion, the degree of deformity (knock knees or bow legs) and the resulting ligament instability as well as the extent of the bone loss on X-ray images.
For me as the doctor, it’s very helpful to develop an individual treatment approach that’s suitable for you if I get the chance to meet you as part of non-surgical treatment. This allows me to support and guide you on your journey and better advise you – including if knee surgery does become necessary.
Surgical treatment: knee surgery
If the desired success is not achieved with non-surgical treatment, I advise you on when is the best time to undergo surgery.
I have implanted over 1,500 total knee joints to date and know that many patients prefer partial joint replacement over total replacement of the knee joint. This is possible if, among other things, the anterior cruciate ligament is stable and only a certain area is affected.
What does knee surgery look like?
If osteoarthritis is detected early enough and if there is a corresponding level of suffering, individual parts of the knee can be replaced (= partial joint replacement).
In the majority of cases, however, the disease is already so far advanced upon diagnosis that only total joint replacement comes into question.
During the procedure, your joint is replaced with an artificial joint. This involves replacing the affected parts of the joint with implants that are usually affixed to the bone with cement, and an inlay made of highly cross-linked polyethylene is clicked into place.
The procedure takes around one to one-and-a-half hours and can be carried out under general or local anaesthetic.
Your anaesthetist will discuss with you what kind of anaesthetic is possible for you.
In more and more cases, we are also implementing new technologies such as robotic assistance during knee joint replacement surgery.
After the surgery
During your inpatient stay, you will relearn how to walk confidently and independently with the help of crutches – generally without any limiting strain. The aim is for you to be able to fully extend your knee and bend it to at least 90° again by the time you are discharged.
You will be discharged from the hospital when the conditions of your wounds and soft tissue have healed regularly, you have learned how to walk with confidence and there are no medical reasons opposing your discharge. This is usually approx. 4 – 7 days after the surgery.
You can then train yourself to walk without the crutches in your familiar environment at home. As a general rule, you should be able to drive independently again after 4 weeks. If you wish, we can also initiate additional rehab therapy.
The first follow-up appointments take place 6 and 12 weeks after the surgery. At this time, from experience, the desired improvements have taken place and you are able to work once more.
Knee joint revision surgery
Over the course of time, as a result of wear particles, an inflammatory reaction occurs, causing bone mass to be degraded and the prosthesis to become "loosened" from the bone. This process weakens the bone, meaning that if there is evidence of loosening , prompt action must be taken.
In principle, the parts of the prosthesis may become loose separately from one another (if either only the femur or only the shin bone is weakened), or both parts may be affected by the loosening.
I place enormous value on finding out whether bacteria are involved or not before every revision surgery.
Revision surgery with bacteria present (2 surgery appointments)
If the loosening can be traced back to inflammation caused by bacteria, an infection is present. In this case, alongside the implant loosening, the infection (osteomyelitis) in particular must also be treated. To do so, the entire prosthesis must be removed, regardless of its degree of loosening. The prosthesis is then replaced with a placeholder containing antibiotics, and a 6-week treatment course of antibiotics takes place. Following this, what’s known as a revision endoprosthesis is implanted.
Revision surgery at an appointment
If there are no bacteria present, the loosening can only be traced back to an inflammatory reaction due to the abrasion. In this case, the replacement can take place in one surgery appointment and can be made conditional on the degree of loosening of the components. In this process, it is always only the loose part that is replaced.
Just as with the primary endoprosthesis, I place value on careful surgical planning to ensure that I am able to react to extraordinary circumstances in the revision situation during the revision surgery – such as major bone defects, poor bone quality, fractures around the implant site. (The implant site is the area that will receive the implant.) This is why we keep a large repertoire of revision and special implants on hand or have ordered them in advance for the revision situation.
This allows us, the surgical team, to perform the optimum reconstruction of the biological situation of the joint.
Arrange an initial consultation with us so that we can find further therapy steps together.
FAQ
How is the knee joint structured?
The knee connects the thighbone to the shin. Part of the knee joint is formed by the kneecap, which serves as a point of support for the generation of force by the quadriceps muscles. The knee joint can essentially only be moved in one plane (extension/flexion). Only when the knee is bent is a minimal rotational movement of the lower leg still possible vis-à-vis the thigh. The joint parts are covered with cartilage that provides a gliding surface, and the joint is sealed by a capsule within which synovial fluid is formed by the synovial membrane for the reduction of resistance and the nutrition of the cartilage. This hydraulic principle works similarly to a shock absorber and is supported by the menisci (crescent-shaped cartilaginous discs) located on the inside and outside between the joint surfaces.
Signs of abrasion may appear in an isolated manner or at multiple parts of the knee joint.
When is the right time for knee replacement surgery?
This depends heavily on the individual situation. In the first few years of cartilage damage, I advise against knee replacement surgery. On the other hand, it makes no sense to wait if the pain is unbearable. In order to consider surgery, a total loss of cartilage with a "bone-on-bone situation" is necessary; in any case, the timing of a knee joint replacement requires careful individual consultation.
What does a knee joint prosthesis (implant) look like?
Knee implants can have varying designs, due to both different models and different sizes. Depending on your symptoms, we have recourse to a large portfolio of modern, tried and tested implants to ensure that we are able to use the right prosthesis for you.
All materials used are specially developed for medical purposes and enable pain-free and permanent function.
How long does a knee implant last?
No prosthesis that has been implanted lasts forever; indeed, the life of implants is limited. It usually lies between 20 to 25 years.
When knee osteoarthritis requires knee surgery
Osteoarthritis of the knee joint is predominantly age-related wear and tear that involves abrasion of the cartilage. The abrasion particles cause an inflammatory reaction that leads to the increased formation of synovial fluid.
What is more, after it reaches a certain level, the inflammation itself has a destructive effect on the cartilage, leading to even more cartilage degradation.
The bone initially reacts to the increasing strain with intensified calcification (sclerosing). Later on, it becomes involved in the self-destructive inflammatory reaction: the bone is degraded and cysts form. To compensate for this, the body forms bony growths (osteophytes) at the edge of the joint to stiffen the destroyed joint in the long run and thus end the sensation of pain.
Arthrosis develops, therefore, over various stages, which are easily visible and can be well assessed on X-ray images, which is why X-ray imaging is the most important diagnostic tool for osteoarthritis.
The disease follows a wave-like pattern:
It is entirely possible for incredibly strong feelings of pain to be followed by intervals in which patients are free from pain. As the disease progresses, however, the frequency of the episodes of pain increases to the same extent as the duration of the pain-free intervals decreases.
The most important message in this context is that osteoarthritis is not curable, but the progression and symptoms can be alleviated (see non-surgical treatment).
When the disease has progressed so far that physical therapy measures, painkillers and anti-inflammatory medication no longer have any effect, the only measure left is an artificial joint replacement (endoprosthesis).