Synovitis

　　Synovitis is a common disease, with the main affected area being the knee joint. The knee joint is the joint with the most synovium, the largest articular surface, and the most complex structure in the human body. Due to the extensive synovium of the knee joint and its location in a relatively superficial part of the limb, it has more opportunities to be injured and infected. Knee synovitis is mainly a group of syndromes caused by knee sprains and various joint injuries inside the joint.

　　Osteoarthritis of the knee joint often develops in the elderly as a secondary condition to knee osteoarthritis, mainly due to mechanical and biochemical stimulation caused by cartilage degeneration and bone hyperplasia, leading to knee synovitis, edema, effusion, and fluid accumulation. In young and middle-aged individuals, it is often caused by acute trauma and chronic injury. Acute trauma includes knee sprains, meniscus injuries, collateral ligament or cruciate ligament injuries, joint effusion or sometimes hemarthrosis, manifesting as acute traumatic synovitis of the knee joint. Sometimes, it can also be caused by simple knee synovial injury, such as mild trauma or long-term chronic knee joint strain, which can cause the knee to gradually swell and develop functional disorders, forming chronic knee synovitis.

　　The swelling type is mainly characterized by swelling after excessive exercise, with varying degrees of pain. The non-swelling type is mainly characterized by joint pain, often accompanied by mild swelling. Studies have confirmed that the two types are essentially the same, but differ in the degree of synovial pathological changes. Researchers have found that after prolonged and excessive single-action exercise of the knee joint, the synovial tissue becomes congested and edematous, and the exudation of red and white blood cells and fibrin is positively correlated with the increase in intra-articular pressure and the decrease in oxygen partial pressure. Moreover, when the exudation rate exceeds the compensatory absorption rate of the synovium, joint effusion occurs, leading to the continuous increase in intra-articular pressure and the continuous decrease in oxygen partial pressure, forming a恶性循环 of chronic aseptic inflammation such as synovial degeneration and fat metaplasia. Therefore, it is believed that the occurrence of traumatic synovitis after excessive exercise is not only related to the repetitive impact on the joint surface and the injury of the joint capsule, but also plays an important role in the development and outcome of the disease process.

　　The synovium is mainly distributed around the joint. It communicates with the joint cavity and secretes lubricating fluid to lubricate the joint. When stimulated or directly damaged by various etiologies (such as osteophytes, arthritis, joint tuberculosis, rheumatism, and traumatic injuries, bone injuries, intra-articular injuries, peripheral soft tissue injuries, and surgery), the synovium produces an inflammatory response, and the response of the synovium to inflammation is the secretion of exudate. Pain occurs, strictly speaking, as long as there is exudative effusion in the joint, it proves that there is synovial inflammation, the main manifestations being joint congestion and swelling, pain, increased exudation, joint effusion, difficulty in activities and squatting, and limited function.

　　Synovitis is caused by poor microcirculation, leading to aseptic inflammation. The main symptom is the production of effusion. The synovium is a membranous tissue surrounding the joint, which not only serves as a protective tissue for the joint but also produces synovial fluid, providing 'lubricating fluid' for joint movement. The production and absorption of synovial fluid is a 'dynamic balance'. When there is a barrier to the reabsorption of synovial fluid, due to the disruption of the dynamic balance of production and absorption of synovial fluid, the production of synovial fluid exceeds reabsorption, resulting in 'joint effusion'.

　　Synovitis is actually a group of syndromes caused by knee joint injury. When synovitis occurs, it is easy to cause temporary or long-term loss of labor power for patients. The symptoms of synovitis in clinical practice can be multifaceted.

　　Early stage synovitis:Joint pain is the main manifestation, and joint swelling is relatively concealed. There will be a creaking sound when squatting or bending, and there will be a severe uncomfortable sensation in the knee joint when climbing stairs or exerting force.

　　Middle stage synovitis:Joint swelling is the main manifestation, and joint pain is relatively concealed. There is an uncomfortable sensation when walking, and some individuals may even experience muscle atrophy and other symptoms. The symptoms in the middle stage are relatively more serious than those in the early stage.

　　Late synovitis:Joint swelling and joint pain are the main symptoms, which are relatively obvious, and are accompanied by effusion, osteophytes, and floating bone fragments. Joint pain worsens when climbing stairs or downstairs, and symptoms may slightly improve during rest. The symptoms of late synovitis are slightly different from those of early synovitis, but the pathology is basically the same. The treatment methods are also basically the same, and only combined minimally invasive interventional therapy needs to be chosen.

　　These are the common symptoms shown by patients with synovitis, which can be seen to have a certain impact on the patient's life. Therefore, timely diagnosis and treatment should be carried out, otherwise synovitis will continue to worsen and eventually lead to bone cancer.

　　The main symptoms of synovitis are joint swelling, followed by pain, dysfunction, muscle atrophy. Therefore, if similar symptoms are found, it is necessary to seek medical attention promptly, make a clear diagnosis, exclude the possibility of other factors, conduct a thorough examination to prevent missed diagnosis, and avoid delaying the disease.

　　During the treatment of synovitis, the joint should stop activity, and even immobilization may be necessary, the purpose of which is to reduce the secretion of effusion. However, this method is prone to cause joint dysfunction, muscle atrophy, and induce other joint lesions. Generally, it is advocated to combine treatment with functional exercise to avoid post-treatment complications. Proper functional activities can accelerate the absorption of effusion. Post-treatment health care is crucial because normal joints are prone to synovitis, let alone after the recovery of synovitis. Therefore, post-treatment health care is very necessary, and doing the above aspects can completely cure synovitis.

　　Patients with a large amount of knee joint effusion or recurrent effusion can undergo joint effusion examination, which can reflect the nature and severity of synovitis. Therefore, joint puncture and synovial fluid examination are of great reference value for the diagnosis and differential diagnosis of knee joint synovitis.

　　Knee joint traumatic synovitis is often misdiagnosed as 'benign joint pain' and treated with simple symptomatic treatment, which is ineffective and often leads to sequelae. Because the degree of synovial lesion and joint effusion changes is positively correlated with the increase of joint cavity pressure and the decrease of oxygen partial pressure, increasing the oxygen partial pressure in the joint cavity and reducing the joint cavity pressure can promote the absorption of inflammation and the repair of the synovium.

　　Patients with synovitis should change their bad habits such as excessive drinking and pay attention to a balanced diet. In the diet, it is recommended to increase nutrition, supplement adequate protein and a variety of vitamins, especially vitamin C and vitamin D, and consume calcium-rich foods such as milk and soy products. Foods should be easy to digest and avoid刺激性, cold, and hard foods. Foods should not only be nutritious but also take into account taste to enhance appetite.

　　It is advisable to reduce the intake of dairy products such as milk and goat milk, peanuts, chocolate, millet, cheese, and sugar, as they can produce prostaglandins, leukotrienes, tyrosine kinase autoantibodies, and anti-milk IgE antibodies that can lead to arthritis exacerbation, recurrence, or deterioration due to their ability to produce allergens. It is also recommended to limit the consumption of fatty meats, high animal fat, and high cholesterol foods, as they can produce ketone bodies, acids, arachidonic acid metabolites, and inflammatory mediators that can suppress the function of T lymphocytes, leading to and exacerbating joint pain, swelling, bone decalcification, and joint destruction.

　　Synovitis is a multifaceted disease, and its onset site is mainly the knee joint. Because the knee joint is the joint with the most synovium, the largest joint surface, and the most complex structure in the human body, and it is also a place with more opportunities for injury and infection, the harm to both patients and society is great. Therefore, timely treatment should be sought for synovitis.

　　1. Drug Therapy

　　Currently, the drugs used to treat synovitis are mainly divided into two categories: oral and topical. Topical drugs are all anti-inflammatory drugs, which can relieve symptoms by eliminating inflammation and have no therapeutic effect on synovial injury or trauma. Some oral drugs have the same mechanism of action as topical drugs, but there are few drugs that can effectively treat synovial lesions. Patients should pay attention to identification when choosing drugs, carefully check the indications of the drugs, and if it is indicated that the drug is for pain, swelling, effusion caused by synovitis, then it means that this drug only has the effect of anti-inflammatory and symptom relief. If patients want to achieve good therapeutic effects, they should treat both orally and topically, and adhere to treatment without stopping medication when the symptoms disappear.

　　2. Puncture Therapy

　　When there is a large amount of joint effusion and high tension, joint puncture can be performed to completely remove the effusion and blood, and sodium hyaluronate can be injected into the joint cavity. It is the main component of joint synovial fluid. Studies have shown that various pathological changes in arthritis are closely related to its reduction and changes in physical and chemical properties. The injection of sodium hyaluronate has the following effects: covering the surface of the joint cartilage, protecting the joint cartilage, preventing or delaying further degeneration, protecting the synovium, and clearing pain-causing substances, which has a significant pain-relieving effect. Improve the joint contracture state, increase joint mobility, and have a positive effect on the synovial fluid of degenerative joints.

　　3. Fixation and Exercise Therapy

　　Early bed rest should be taken, with the affected limb elevated, and elastic bandage compression bandaging can be used, and weight-bearing should be prohibited. During the treatment period, exercises for the quadriceps femoris muscle can be performed to contract and relax, and in the later stage, the extension and flexion exercises of the knee joint should be strengthened. This has a positive effect on eliminating joint effusion, preventing atrophy of the quadriceps femoris muscle, preventing recurrent synovitis, and restoring the extension and flexion function of the knee joint.