Joints are the movable junctions of two bones – and a true marvel of nature. They allow the body and all limbs to move smoothly in almost any direction. Their ingenious structure also makes joints shock absorbers that cushion great loads on the bones. The joints can withstand a great deal: A knee joint, for example, can withstand up to 500 kg, the hip joint almost twice that.
Structure of the joints
The two parts of the bone forming the joint are adapted to each other by shape in such a way that one part usually corresponds to a socket, the other to the head matching it. If the socket part is poorly formed, as in the knee, for example, crescent-shaped discs of cartilage stabilize the fit of the bones – called menisci.
To make contact in the joint soft and as low-friction as possible, the parts of the bones that touch each other, also called the joint bodies, are covered with a thin layer of cartilage. This cartilage serves both as a sliding surface and to cushion shocks.
The cartilage is nourished by the synovial fluid, since it has no blood supply itself. This fluid, which fills the joint space between the ends of the bones, is gel-like and has a lubricating and shock-absorbing effect.
Degradation of cartilage
With age, the elasticity of cartilage and synovial fluid decreases. At the same time, the water content in the cartilage also decreases, so that the joints increasingly lose their cushioning effect. The once smooth surface of the cartilage becomes rough, so that it rubs against the other side of the joint. In extreme cases, the entire cartilage layer can dissolve down to the ends of the bones, so that the ends of the bones rub directly against each other.
These joint diseases, which occur due to changes in the articular cartilage, are called osteoarthritis. Osteoarthritis is the medical term for a group of rheumatic diseases described as “degenerative rheumatic diseases.” Osteoarthritis initially manifests itself as morning stiffness of the joint.
The discomfort and pain continue until sufficient synovial fluid has reached the joint as a result of movement. In medical terms, this is known as start-up pain. Weight-bearing joints such as the knee and hip are particularly affected. Arthritic disease of the joint is always caused by overloading or incorrect loading – the natural aging process of the cartilage is not responsible.
The following causes mostly underlie overloads and incorrect loads:
- Overweight
- Poorly healing bone fractures
- Occupational overload, e.g. of a leg
- From birth misaligned joint positions, e.g. the hip.
- Bone structure disorders
Fit joints with glucosamine
A key building block of cartilage tissue is glucosamine, an amino sugar that can be produced by the healthy and youthful organism from various components of the diet. However, as we age, the body loses the ability to absorb glucosamine from food. In addition, today’s foods contain few natural sources of glucosamine, which include mussels, crabs, shrimp and lobster. Cartilage and connective tissue parts from other animals are also very rarely on the menu today.
Glucosamine also serves to form synovial fluid, the so-called synovial fluid. As a result of a glucosamine deficiency, the synovial fluid, which is viscous in itself, becomes thin and watery. The cartilage of the joint capsules also shrinks and becomes brittle. This eventually leads to erosion of the cartilage layers in the joints, causing inflammation, swelling, stiffness and pain.
Joint pain: what to do?
- Engage in sports that are easy on the joints (walking, swimming, cycling).
- Avoiding fatty foods
- Do not smoke, little alcohol
- Watch your weight
- Avoid heavy loads.
