Information about knee replacement surgery

Video: „Knee replacement -- what there is and which new developments make sense?” (german language)

Knee replacement

A perfect alignment of the artificial knee joint is enormously important. This is where cutting templates that are made individually for each patient help. Otherwise, well-operated unicondylar prostheses are a valuable alternative, because it is not necessary to replace the entire knee joint in every patient.

The artificial knee joint

Do you feel that walking is increasingly difficult after only a few steps? Are you in pain when climbing stairs or even on level ground? You may be suffering from gonarthrosis, the most common knee joint disease. In case of osteoarthritis, the articular cartilage wears out or even completely disappears in some places. As a result, the bones in the joint rub directly against each other. Even small movements can cause severe pain, because unlike the cartilage, the bones or periosteum are supplied with nerves. Without a protective cartilage layer, the bones wear off and may deform under certain circumstances. The conservative treatment options for gonarthrosis are diverse. A coordinated movement therapy, for example cycling or swimming, helps to relieve the joint. In addition, cartilage growth preparations containing glucosamine and chondroitin sulphate as well as injections of hyaluronic acid into the joint are useful for better lubrication. However, if these conservative measures fail, the provision of a knee prosthesis should be considered.

Das künstliche Kniegelenk

A total knee joint is not always necessary

The cartilage wear is limited only to partial areas in the knee joint in about 30% of my patients. In these cases one can consider replacing only these worn areas with a partial knee prosthesis. One also speaks then of a unicondylar prosthesis. Healthy joint sections such as the patellar bearing, the cruciate ligaments and one of the two femoral condyles are preserved. As a result, the knee joint feels much more natural with a partial then with a total joint replacement. In addition, tissue trauma is lower, convalescence faster and the patient more satisfied overall. However, it requires a experienced surgeon to reliably achieve the good surgical results of a unicondylar prosthesis. I use as an implant the “Oxford” model, which has been proven for decades, from the Zimmer Biomet company.

Nicht immer ist ein ganzes künstliches Knie erforderlich

The principle of a total knee endoprosthesis (TEP)

The human body is one of nature’s wonders. The countless joints simply work together perfectly. A new joint, such as the knee joint prosthesis, must be optimally fitted here. It has only one task: You should finally be able to move again without pain. The operation is now a standard procedure. The knee joint prosthesis consists of at least two main parts and is designed as a surface replacement prosthesis. Imagine the prosthesis as a covering of the damaged articular surfaces. It consists of a “femoral component” that is cemented to the end of the femur and a “tibial component” with an inlay that replaces the upper end of the tibia. This inlay works as a so-called gliding partner of the femoral implant, so it serves as a spacer between the implants and ensures smooth, painless movements. The kneecap (patella) slides over the anterior shield of the femoral component during movement. In most cases a patellar prosthesis is cemented to the inside of the patella.

Das Prinzip einer Knie-Total-Endoprothese (TEP)

Modern high-performance prostheses

The kinematics of a natural knee joint is extremely complex. Artificial joints can only try to approach natural kinematics. The Smith & Nephew company with its bi-cruciate stabilizing knee endoprosthesis JOURNEY II BCS has come very close to this goal in modern knee arthroplasty. This is a kinematic guided knee system. BCS stands for “Bi-Cruciate Stabilized” and means that the stabilizing function of both cruciate ligaments is restored. The goal of this knee joint is to achieve a higher patient satisfaction after knee replacement. I can offer you a range of modern high-performance knee replacements.

Moderne Hochleistungsprothesen

Individual cutting blocks (VISIONAIRE®) for a potentially perfect alignment

I have used the so-called VISIONAIRE® technology since 2011 to optimize the operation. Here, cutting blocks are made in a complex process individually for each patient before the operation. The surgeon thus receives additional support for the pre-operation planning.

In addition to a standing full-length leg X-ray, VISIONAIRE® also makes a magnetic resonance tomography (MRI) of the knee. This MRI must be made with a certified radiologist specifically for VISIONAIRE® technology. The images allow the preoperative calculation of the mechanical leg axes and a precise three-dimensional representation of the individual patient anatomy. Based on the individual X-ray and MRI images, cut-to-length templates are made of medical nylon plastic, which are exactly adapted to the individual knee anatomy of the respective patient. So much of the planning takes place in a calm environment and not just during the operation. During surgery, the surgeon uses these templates to prepare the knee for implantation and can precisely align the artificial joint with the leg axes and anatomical landmarks.

Advantages of VISIONAIRE® technology

The advantages for you as a patient are on the one hand more likely a better surgical outcome and possibly a longer shelf life of the artificial knee joint. Secondly, when using the VISIONAIRE® technology, some surgical steps to date with standard instruments can be dispensed with because the individual VISIONAIRE® templates significantly reduce the need for instruments. This shortens the duration of the operation in a patient-friendly way: The patient sometimes requires less anesthetic and loses less blood, which also reduces the risk of intra operative infection. In addition, the eliminated surgery steps can be tissue-sparing, reducing the risk of complications, such as: pulmonary fat embolism.

The Visionaire technology supports the surgeon but can never replace his experience. So far, the additional costs for the preparation of the VISIONAIRE® cutting blocks and the special MRI are not covered by the health insurance companies. If you opt for the VISIONAIRE® technology as a patient, you will receive a separate invoice from the clinic The total cost is currently 765 euros.

Vorteile der Visionaire-Technologie

What is the clinical outcome after total knee replacement?

The postoperative results after implanting a knee prosthesis are good: Around 85 to 90% of the patients are happy and satisfied. This vaule is somewhat lower than with a hip prosthesis. This is due to the following problem areas:

  • More complex anatomy:
    While a hip joint – surrounded by large muscle groups – is basically just a ball in a socket, the knee joint is much more complex. In addition to ligaments and capsule, as well as the extensor tendon with the embedded patella, the leg axes play a decisive role for a balanced joint. Without a basic understanding of the anatomy and biomechanics of the knee joint, proper implantation of a knee prosthesis becomes a random hit.
  • Limited painful mobility:
    The first three months after surgery, your knee joint will usually be a little overheated and painful. It is important to develop good mobility from the start. The goal should be a flexion of at least 90 degrees after one week. Although some patients with an artificial joint reach the full flexion of over 140 degrees, the average flexion with knee prosthesis is about 120 degrees.
    Unlike the hip joint, extend the knee (or at least almost completely) stretch the knee joint is crucial. An energy-efficient, fluid stride is only possible when the extended leg can be swept forward. In addition, fatigue-free standing only works if the knee joint can be stretched far enough. Unfortunately, the extent of movement after completion of rehabilitation sometimes leaves a lot to be desired, not least because of increased sensitivity to pain after the procedure.