The knee joint is the largest joint of the human body. It is composed of three bones whose movements are guided exclusively by muscles, ligaments and tendons. The menisci – two half-moon-shaped discs consisting of fibrous cartilage – are located between the thigh bone and the shank bone on the inner and outer side of the knee joint. They distribute the load in the joint to a large surface and work like a buffer or shock-absorber system.
The joint cartilage has another structure and differs from the meniscus. It is an up to 5 mm thick layer covering the entire bone surface inside the joint. This highly elastic and water-containing tissue ensures a smooth, nearly frictionless motion sequence.
Injuries or damage to these cartilaginous structures are usually beyond remedy. In the medium or long term, they may lead to joint wear – better known as osteoarthritis.