Knee joints, artificial

Postmastectomy reconstruction Artificial hip. knee 18. Artificial finger, toe joints Tom ligaments Natural-action Seattle Foot Aorta... 

Another widely used surgical procedure is knee replacement. In this operation the natural components of the knee joint are replaced with an artificial femoral component made of metal that interfaces with a tibial plateau made of ultra-high molar mass poly(ethylene). Implantation of these joints is becoming more widespread, though the demand for them is not as great as for hip replacement. 

Excess bone/scar tissue formation - this may occur around the artificial knee joint, resulting in restricted joint movement. Removal of the excess bone/scar tissue may necessitate further surgery to restore movement. 

Certain salts of radioactive chromium (1) are used as radiopharmaceutical tracers in various hematological procedures. Chromium compounds are also used in oral and parenteral nutrition and in artificial hip and knee joints. Chromium picolinate has been promoted as a nutritional supplement and has received a great deal of interest because of its possible beneficial effects on muscle strength and body composition. 

Transtibial prosthesis Artificial leg for amputees with the amputation between the ankle and the knee joints (transtibia)... 

Scientists have used water to create almost frictionless lubricated surfaces that stay slippery even under heavy loads. The coating they have developed could shed light on how natural joints are lubricated and provide new ways to protect hip and knee joint implants from friction damage. Over time, the body s immune systan attacks artificial joints. Researchers are now targeting biological interactions rather than trying to solve the problem with new materials. 

Bones, and their joints, are sometimes damaged by accidents, disease, aging, etc. When hip and knee joints are damaged, patients sometimes feel severe pain, and have much difficulty in walking, since these joints must slide smoothly at least a few thousand times every day under a load over several times body weight. In such cases, the joints must be replaced with artificial ones. The present number of hip and knee joints replaced with artificial ones total about 100 000 in Japan, and 600 000 in the United States. 

Schaldach, M. and Hohmann, D., Eds. 1976. Advances in Artificial Hip and Knee Joint Technology, Springer-Verlag, Berlin. 

Paul J. Loading on normal hip and knee joints and on joint replacements. In Schaldach M, Hohman D, editors Engineering in medicine. Vol. 2. advances in artificial hip and knee joint technology. New York Springier-Verlag 1976. 

Dowson D, Jobbins B, O Kelly J, Wright V. A knee joint simulator, chapter 7. Evaluation of artificial hip joints. UK Biological Engineering Society 1977. p. 79-90. 

Medicine has made major advances in the past 50 or so years partly by the use of devices to improve patient health. These devices include artificial hearts and pacemakers, machines for artificial kidney dialysis, replacement joints for hips, knees, and fingers, and intraocular lenses. These devices need to survive in sustained contact with blood or living tissue. 

The October 1996 issue of the Dutch magazine Natuur Techniek makes mention of a research of the University of Bristol, Great Britain into the effects of implanting artificial hip joints and knees into the body. This research showed that metal particles and pieces of plastic, cement and polymers are gradually released from the artificial joints. Such particles were found in the neighbourhood of joints and lymph nodes. However, they were also present in the bone marrow, the spleen and the liver. The more artificial limbs are exposed to loads, the more particles will be released. So far there are no indications of health hazards, but it is not possible to predict long term effects. 

---