Artificial joint replacement
In an advanced stage of cartilage destruction, usually several joint parts are involved. A malformation of the knee joint and increasing stiffening occur. Patients complain about pains during weight-bearing and while at rest. Even at night the patient is no longer pain-free. Length of walking becomes increasingly short, and the quality of life becomes significantly limited. Destroyed joint surfaces appear on the x-ray image, usually associated with visible joint malformations. Once conservative treatment possibilities have been exhausted (e.g., physical therapy, medications) and with corresponding pressure pain, construction of an artificial knee joint is the only alternative.
The damaged joint surfaces are replaced by surface prostheses, either in the form of a partial prosthesis (sled prosthesis) or a total prosthesis. Thanks to the use of these modern types of prostheses, only very little bone material must be removed. The body's own ligament structures (side ligaments, cruciate ligaments) remain intact. All prosthesis types consist of a component for the upper and lower leg. The development of prosthesis types that come very close to approximating natural movement of the normal knee joint (roll-slide movement) has significantly increased good outcomes in recent years.
The size of the prosthesis is individually adjusted for the patient based on a planning sketch. It is either cement-free (press-fit technique), a hybrid total endoprosthesis (upper leg part cement-free, lower leg cemented), or both components are implanted with bone cement. The sliding surfaces for the upper leg part are made of chrome-cobalt alloys; the sliding part on the lower leg consists of polyethylene parts, which allow a completely natural role-slide procedure and significantly reduce wearing away. On the average, the lifetime of the joint total prostheses is 10-15 years.
Joint replacement operations are performed only on an inpatient basis (approximately 10-14 days). Rehabilitation begins immediately after the operation. The patients are treated daily with physical therapy and lymph drainage. Motorized splints are available for passive movement exercises. After the stay in an acute care hospital, most patients are transferred for another 3-4 weeks to a rehabilitation clinic. A period of 3-4 months is to be reckoned on for total treatment. With a normal course of the operation and after successful rehabilitation, sports such as bicycling, swimming, and golfing are again possible.
The medial (sled) knee endoprosthesis – the "half" artificial knee joint
Isolated occurrences of wear and tear on the inner side of the knee can be taken care of in various ways by an operation. One possibility is to relieve the arthrosis on the inner side by axial correction. If there is little or no bowlegged bone, or if the wearing away or arthrosis of the inner side has already progressed too far, the possibility exists of replacing the surface of the affected area in isolation. Implanting such a knee prosthesis occurs with a minimally invasive procedure.
A correctly inserted medial endoprosthesis today functions without any problem for 15-20 years.
Appropriate preconditions are: advanced arthrosis of the inner side, not too extensive knockknee or bowlegged position, stable ligaments, extension limitation up to 10°, age 60 years and over. An arthrosis behind the knee disk is not a reason for exclusion.
The operation can be performed under total anesthesia or spinal anesthesia, and as a rule lasts between 40 and 70 minutes. Access occurs along the inner side of the knee disk ligament. The incision is about 6-8 cm long. The defective joint surfaces along with a little bit of bone are removed from the tibia and the thigh bone. The final prosthesis is cemented in. There then follows the closing of the wound and drainage to avoid blood effusions. The whole operation takes place while the blood flow is shut off (pressure cuff), so that the loss of blood is minor.
You are already mobilized on the first day after the operation. Starting with the first day, you may put full load bearing on your leg using crutches. The crutches can be dispensed with after 3-4 weeks. Discharge from our clinic occurs between the fifth and eighth day after the operation. With the help of physical therapy, the extent of movement increases to over 120° in the first 6 weeks. Full extension is usually achieved after some delay.