Synovitis is an irritation or injury to the synovial membrane, resulting in an inflammatory response, synovial hyperplasia, increased secretion of exudate, resulting in swelling and fluid accumulation in the joint, and in severe cases, redness and heat and severe pain in the joint. Causes of synovitis: infection (bacterial, viral, fungal, etc.), trauma, immune diseases (rheumatoid, ankylosing spondylitis, etc.), joint degeneration (inflammatory factor stimulation), etc. Diagnosis of synovitis: joint swelling and fluid accumulation, synovial hyperplasia can be diagnosed as synovitis. However, the diagnosis of synovitis alone is not clinically helpful or meaningful. The key is that the causative agent must be found. If it is an infection, the infection must be fought. If it is rheumatoid, anti-rheumatoid drugs must be applied. And so on. However, in clinical practice, the cause of synovitis cannot be found in some patients and can only be treated according to the doctor’s experience, and the efficacy is difficult to guarantee. Treatment of synovitis: 1. Treatment of the cause: If the cause is clear, treatment should be directed at the cause. Antibiotics should be used for bacterial infections. Those with immune diseases should be treated with anti-immune therapy. This is the key measure to cure the disease; 2. Symptomatic treatment: Reduce the inflammatory response. In the acute stage, joint activity should be reduced to ease the burden on the joints. Those with severe swelling can undergo joint puncture and fluid extraction, and medication can be given at the same time. Those with red and hot joints should have cold therapy (ice packs). Oral and topical anti-inflammatory and analgesic drugs (e.g. Fotalin, Fenbuterol, Anti-inflammatory pain, Cilobal, etc.) can be used; 3. Surgery can be considered for a small number of patients for whom conservative treatment is ineffective. Joint irrigation and irrigation or arthroscopic synovial debridement can be performed.