Knee prothesis

If the non-surgical treatments for knee complaints offer insufficient results, the orthopedic surgeon can decide together with you to intervene surgically. Performing an operation for knee complaints can consist of joint-sparing operations such as arthroscopic surgery (keyhole surgery) or an osteotomy (position adjustment) or joint replacement operations. Which procedure is most suitable depends on the cause of the knee complaints and sometimes also the individual wishes of the patient.

Joint replacement surgeries

The joint replacement operations consist of total and half knee arthroplasties.

Knee prosthesis

The knee prosthesis is a frequently used technique to treat (end-stage) osteoarthritis. This operation has been done for many years. If non-operative treatment does not have the desired result, total and half knee arthroplasties are considered. The knee prosthesis ensures that the painful and poorly moving joint can move painlessly again. In most cases, the cause of the knee complaint is joint wear and tear (osteoarthritis).

When a knee prosthesis is placed, the worn joint surfaces of the femur and tibia are replaced by a metal prosthesis with a hard plastic part in between.

Total knee replacement

The artificial knee is placed many times a year.

The operation

During the operation of placing a total knee arthroplasty, the knee is opened at the front by a vertical incision over the knee. This cut of about 20 centimeters allows access to the knee joint. The orthopedic surgeon will remove the affected articular surfaces and with special instruments and fittings the bone will be adapted to the shape of the prosthesis. When this is done, the joint halves will be replaced by the metal prosthesis. The prosthesis is visible on an X-ray. At the Eisenhower Clinic, we use a cemented prosthesis. These prosthetic parts are clamped in the bone with this cement. When the cement has hardened, the intermediate disk of hard plastic will be placed and the knee joint will be closed again. In general, it is not necessary to place a kneecap prosthesis. This is done in case of severe kneecap wear or rheumatism.

Post-treatment

The operation takes about 1 to 1.5 hours. You may get out of bed a few hours after the procedure and the physiotherapist will start the rehabilitation process with you. You can generally go home the next day. The rehabilitation mainly consists of bending and straightening the knee together with muscle training. In the first period, the knee will still be warm and swollen from irritation after bending and stretching. This takes about six months. In addition, night pains are common in the first weeks after the procedure. The total rehabilitation period after a knee prosthesis placement is one year. After this period, the end result of the knee prosthesis can be expected. The exact rehabilitation period differs from patient to patient.

Half knee prosthesis

As the name implies, the half knee prosthesis does not replace the entire knee joint, but only a part. This usually replaces the inside (medial side) of the knee joint.

The operation

During the operation of placing a half knee prosthesis, the knee is opened at the front by a vertical incision over the knee. This incision can be much smaller than the incision required for a total knee arthroplasty. This cut allows access to the inside of the knee joint. The orthopedic surgeon will remove the affected articular surfaces on the inside of the knee and with special instruments and fits the bone will be adapted to the shape of the prosthesis. When this is done, the joint halves will be replaced by the metal prosthesis. The prosthetic parts are clamped in the bone and will grow in. The intermediate disc made of hard plastic can then be placed and the knee joint is closed again.

Post-treatment

The after-treatment of a half knee prosthesis is almost the same as that of a total knee prosthesis. Although it goes a bit faster. The operation takes about 1 to 1.5 hours. You may get out of bed a few hours after the procedure and the physiotherapist will start the rehabilitation process with you. You can generally go home the next day. The rehabilitation mainly consists of bending and straightening the knee together with muscle training. In the first period, the knee will still be warm and swollen from irritation after bending and stretching. This takes about six months. Night pains can also occur in the first weeks after the operation after a half knee prosthesis. Usually this is present to a lesser extent compared to a total knee arthroplasty. The total rehabilitation period after a half knee prosthesis placement is one year. Although the process is faster and often less painful, the rehabilitation period takes as long as a total knee replacement. The final result is achieved after one year, although the exact rehabilitation time may vary per patient.

Type of prosthetics

The different types of knee prostheses have to do with the way in which the prosthesis is attached to the bone; with cement (cemented) or without cement and with ingrowth material (uncemented).

The difference between a cemented prosthesis and an uncemented prosthesis mainly lies in the way of fixation in the bone. With an uncemented prosthesis, the prosthesis surface is made of a rough material, which stimulates the body to produce extra bone. This extra bone grows into the rough surface of the prosthesis. This causes the prosthesis to become stuck. With a cemented prosthesis, the prosthesis is clamped to the bone with a specially developed bone cement. There is no clear benefit to either technique, although the National Orthopedic Association recommends always cementing the prosthetic part on the lower leg. The preference and experience of the orthopedic surgeon determine the technique used. In addition, there are different manufacturers who have all developed a slightly different design of the prosthesis. Regardless of which type of prosthesis is placed, 9 out of 10 patients are still satisfied with their knee prosthesis after at least 10 years. There is an (inter)national list of proven good prostheses. At the Eisenhower Clinic, we use the NexGen Knee and the Oxford Partial Knee from Zimmer Biomet for total knee arthroplasty and partial knee arthroplasty.

Complication risks

Every operation has risks, including the placement of a knee prosthesis. Although these complications only occur in a few cases, it is important to be aware of them.

Important surgical risks are wound healing disorders, nerve injury, infection and thrombosis in the leg. There may also be changes in the position of the components of the knee prosthesis or, in the longer term, the prosthesis components may become detached, requiring revision surgery.