Degeneration of the posterior horn of the medial meniscus of the knee joint can be caused by age factor, excessive weight bearing, arthritic irritation and other reasons. 1. Age factor: with the increase of age, the posterior horn of the medial meniscus of the knee joint and other parts of the normal aging, degeneration phenomenon, local stress increases, which can lead to local degeneration and other physiological changes. 2. Excessive weight-bearing: excessive weight-bearing activities in the knee joint can lead to excessive wear and tear of the meniscus and ligaments and other soft tissues in the knee joint, and repeated local friction and extrusion will accelerate the degeneration of the posterior horn of the meniscus and other parts. 3. Arthritis stimulation: rheumatoid arthritis and gouty arthritis and other diseases involving the knee joint, can increase the stimulation of the posterior horn of the medial meniscus of the knee joint, accelerating the process of degeneration. When degeneration of the posterior horn of the medial meniscus of the knee joint occurs, it is necessary to consult a doctor in time to clarify the condition of the disease and carry out appropriate treatment, which will help to alleviate the uncomfortable symptoms as soon as possible.