The knee joint: it is the joint which is put most stress on.
The knee joint is not only the largest joint of the entire human body, it is also the one that is exposed to the most load and stress: with every normal step, the "hinge joint" between thigh and lower leg has to bear the entire body weight. When running or jumping, this may even increase to a maximum of 1.5 tons weighing on the joint. A complex mixture of bones, cartilages, menisci, sinews and ligaments makes the joint tolerant towards exercise and prevents it from bending in at every step or jump. The knee joint can be easily injured, though.
A variety of causes and clinical pictures
Chronic professional overexertion, acute sports injuries, bow-legs, metabolic diseases, overweight and inappropriate footwear - there are many potential causes for knee problems. Thus, there is also a vast list of corresponding clinical pictures: ranging from A like arthrosis Z like damage of the zygoapophyseal joints. Modern diagnostic options, well-devised surgical techniques and instruments as well as improved training and rehabilitation methods enable in most cases for treatment of even severe knee defects as to allow restored mobility without pain.