What causes synovitis? Here are the reasons

The causes of synovitis are different, and there are different types. In young people, synovitis may be caused by cold infection, while in the elderly, it is more caused by cartilage degeneration and bone hyperplasia. At the same time, long-term excessive exercise can also cause this problem.

1. Synovitis in young people

In young people, knee synovitis is mainly caused by knee sprain and various intra-articular injuries, such as meniscus injury, synovial injury, cruciate ligament or collateral ligament injury, intra-articular effusion or sometimes blood accumulation, manifesting as acute traumatic synovitis of the knee. Intra-articular injury and dislocation can sometimes be caused by simple synovial injury to the knee joint, such as minor trauma, or long-term chronic knee strain. Coupled with the invasion of wind, cold and dampness, the knee joint may gradually become swollen and dysfunctional, forming chronic knee synovitis. Another reason is infection, among which synovial tuberculosis is the most common. Generally speaking, the synovium is rich in blood vessels, has good blood circulation, and has strong resistance to bacteria. However, in the case of tuberculosis infection, the disease progresses slowly and its symptoms are sometimes better and sometimes worse. This is one of the chronic synovitis of the knee joint.

2. Synovitis in the elderly

Knee synovitis is often secondary to knee osteoarthritis in the elderly. It is mainly due to the mechanical and biochemical stimulation caused by cartilage degeneration and bone hyperplasia, which leads to synovial edema, exudation and effusion of the knee.

3. Excessive exercise

The joint swelling type is mainly caused by excessive exercise, and the pain varies in severity. The non-swollen type is characterized by joint pain, often accompanied by mild swelling. Studies have shown that the two types are essentially the same, differing only in the degree of pathological changes in the synovium. Researchers have found that after prolonged and excessive exercise of the knee joint in a single motion, the synovial tissue becomes congested and edematous, and the exudation of red, white blood cells and fibrin is positively correlated with the increase in intra-articular pressure and the decrease in oxygen partial pressure. When the exudation rate exceeds the compensatory absorption rate of the synovium, joint effusion occurs, which leads to a vicious cycle of continued increase in intra-articular pressure and continued decrease in oxygen partial pressure. Over time, chronic sterile inflammation such as synovial degeneration and fatty metaplasia is formed. It is believed that the occurrence of traumatic synovitis after excessive exercise is not only related to repeated impact on the joint surface and damage to the joint capsule, but also plays an important role in the development and outcome of the disease.