OP
The operation of an artificial knee joint can be performed under general anesthesia as well as under a so-called spinal anesthesia. With general anesthesia, the patient sleeps during the operation and therefore does not notice anything of the entire operation. Under general anesthesia, however, the patient no longer breathes on his or her own, which means that machine ventilation of the patient is included for the duration of the operation.
In contrast, the patient is awake during spinal anesthesia. This means that he or she is aware of the entire course of the operation. The anesthetic medication is injected into the spinal canal, which is called the spinal canal.
Depending on the height of the spinal column that is punctured, the parts of the body that are completely anesthetized also differ. In addition to this, when operating on an artificial knee joint, a pain catheter can be placed in the immediate vicinity of the nerves responsible for the legs. This catheter is often used for pain therapy after the operation.
The actual operation of the artificial knee joint takes about 1-2 hours. The operation of the knee joint is started with an incision in the middle of the knee. The operation often takes place in so-called bloodlessness.
This serves to prevent the tissue from bleeding too much during the operation. For this purpose a cuff is placed around the thigh, which is then inflated at the beginning of the operation to reduce the blood flow. After opening the knee joint, the soft tissues as well as the kneecap are usually kept outwards with various tools and levers.
The damaged cartilage and structures are now removed. Depending on the type of prosthesis to be inserted, the procedure differs slightly. Once the knee joint is opened, the damaged structures are removed first of all.
This means that damaged ligaments or even the menisci are removed. In addition, bony attachments, also called osteophytes, are removed from the joint surfaces, as they can later restrict the natural mobility of the knee joint. Now so-called sawing templates are attached to the bones.
They are placed where the cut surface will later be. These sawing templates are used to create optimal surfaces for the later artificial knee joint.After sawing off the defective joint surfaces, holes are drilled for anchoring the prosthesis. Once the rough preparation is done, the prosthesis is fitted with a so-called test prosthesis.
This is used to achieve the optimal size and correct fit of the final prosthesis. In the last step, the final knee prosthesis is inserted into the knee using so-called bone cement. There is also the possibility of a cementless prosthesis.
For this, there must be enough good body-own bone material available to anchor it. In some cases it is necessary to replace the joint surface of the kneecap as well. Once the artificial knee joint has been installed, the operation is then finished.
The joint capsule is closed with a suture. Sutures then follow through the lower layers of tissue to bring the skin layers closer together and thus relieve the tension from the skin suture. Finally, the closing skin suture is applied during the operation of the artificial knee joint.
All articles in this series:
