The efficacy of joint irrigation treatment is confirmed by the following irrigation mechanisms: 1. The irrigation can flush out the dislodged cartilage debris and a part of the intra-articular free body caused by the subsynovial osteoarthrosis from the joint cavity, thus alleviating the friction of the cartilage surface and the inflammation caused by these debris or the pain caused by the interlocking of the joint. 2, because the folding of the synovial membrane is another cause of knee pain, through flushing, the vacuum in the joint cavity can be relieved, so that the synovial membrane around the patella folds out of the non-contact area of the articular cartilage, thus relieving the synovial membrane folding can be stretched to relieve pain. Some literature points out that the injection of saline into the joint can increase the intra-articular pressure so that the synovial folding can be stretched to relieve pain. 3. The decrease in the concentration of hyaluronic acid in the synovial fluid of osteoarthritis joints, the decrease in the ability to absorb shock during movement due to the denaturation of the synovial fluid, and the loss of cartilage due to osteoarthritis resulting in narrowing of the joint space, and the increase in pressure in the joint due to the most inflammatory exudate, can cause joint pain. Flushing can adequately drain out this degenerated synovial fluid and provide intra-articular decompression. This results in the production of new, relatively normal synovial fluid. The denaturation and increase of these synovial fluids takes a considerable amount of time and therefore relieves resting joint pain over a longer period of time. 4. Joint irrigation reduces the concentration of some inflammatory mediators such as prostaglandins, interleukins 1, 6 and 8, as well as tumor necrosis factor and metalloproteinases (MMPs) in the joint fluid. There may also be a stimulatory effect on synovial fluid secretion and increase in chondrocyte water and nutrition. Whether there is an effect on the release of collagenases in the joint is inconclusive. Collagenase specifically destroys matrix type I, II, III and type I collagen, especially type II collagen, the main component of cartilage, has the greatest destructive effect. 5, joint rinsing can also adjust the osmotic pressure of synovial fluid, replenish electrolytes such as sodium, potassium, magnesium and calcium; increase the nutrition of cartilage, which is conducive to repair and acidification of joint fluid, according to clinical reports, it is believed that acidic rinsing fluid is better than neutral and alkaline fluid.