Osteoarthritis is a disease in which the integrity of the articular cartilage is compromised for a variety of reasons, causing symptoms and signs. The underlying cause is damage to the articular cartilage, softening of the cartilage matrix and loss of elasticity and strength, followed by subchondral osteosclerosis or cystic degeneration and bone redundancy, resulting in pain and motion impairment, and in severe cases, disability of the affected limb. Although osteoarthritis starts in the cartilage of the joint, it can affect the entire joint structure and eventually lead to joint deformity and loss of function, which is why some people call it “the cancer that never dies”. Age, gender, obesity, joint overuse and injury are important factors in the occurrence of osteoarthritis The occurrence of the disease is related to the following factors: 1. Obesity: In addition to the mechanical factors caused by obesity, it is also related to the posture, gait, change in exercise habits and systemic metabolic factors caused by obesity. Some data show that the incidence of knee osteoarthritis in obese women is four times that of normal weight women, and if the weight reduction of 5 kg in 10 years can reduce the incidence of symptomatic knee osteoarthritis by 50%; 4, race: the incidence of hip osteoarthritis in Westerners is high, while the incidence of knee osteoarthritis in Easterners is high; 5, joint overuse and injury: some special occupations are susceptible to Osteoarthritis, such as miners, heavy manual laborers, professional athletes, dancers, etc., mainly due to long-term wear and tear of joint cartilage by high-intensity stress or injury; in addition to wearing high-heeled shoes with a sharp or wide heel, nutritional disorders of joint cartilage, metabolic abnormalities, neurological abnormalities and changes in the biomechanical environment of the joint can trigger osteoarthritis. Major clinical and imaging manifestations of osteoarthritis Osteoarthritis can occur in all joints of the body, showing pain, swelling, friction sounds, deformation and limitation of movement in the corresponding joints. The incidence of knee arthritis is higher because the knee is a joint that is heavily loaded, active, and susceptible to trauma, strain, and wind and cold stimulation. In the early stages of the disease, pain occurs during activity and is apparent during weight-bearing, but can be relieved at rest, and then progresses to persistent pain. Osteoarthritis of the knee joint can also lead to squatting, stair climbing, inversion of the affected limb and flexion contracture deformity in severe cases. Early X-rays are unchanged and subsequently show narrowing of the joint space with uneven width, but no bony ankylosis develops. The subchondral bone plate is rough and unevenly dense, with hyperplasia and sclerosis, and bony subarticular surface cysts. Bone spurs or lip-like protrusions. In late stages, joint subluxation and joint free bodies appear. Treatment of osteoarthritis In 2002, the American College of Rheumatology proposed new clinical treatment guidelines for osteoarthritis, including non-pharmacologic, pharmacologic, and surgical treatments. Non-pharmacological treatment mainly refers to joint protective measures and physical therapy. Drugs are divided into 2 major categories: non-specific drugs for osteoarthritis and specific drugs for osteoarthritis. Drug therapy has the advantages of simplicity, reliability and ease of maintenance, and has not yet been generally emphasized in this area in China. 1.Non-specific drugs for osteoarthritis These drugs have rapid analgesic and symptom improvement effects, but do not affect the pathology of osteoarthritis and lesion structure, including antipyretic analgesics, non-steroidal anti-inflammatory drugs, glucocorticoids and opioid analgesics, etc. 2, the treatment of osteoarthritis specific drugs (1) symptom relief drugs: hyaluronic acid as intra-articular viscous filler, can restore the viscoelasticity of synovial fluid, relieve pain and improve the function of the joint, the force of joint activity in the short term to improve. Possible mechanisms of action are inhibition of inflammatory mediators, stimulation of cartilage matrix synthesis, inhibition of cartilage degradation, and direct protection of nerve endings that feel injury. The therapeutic effect usually appears within a week after treatment and is maintained for several weeks to months. (2) Condition-modifying drugs: Glucosamine: Chondrocytes can use glucosamine to synthesize large molecules of mucopolysaccharide, which is an important component of the cartilage matrix and maintains the morphology and function of cartilage together with type II collagen fibers. It is considered to be the first drug or slow-acting agent to modify the condition of osteoarthritis and is called a chondroprotective agent. The hypothesis that glucosamine supplementation relieves symptoms in OA patients was developed more than 30 years ago and is now available in three forms: glucosamine hydrochloride, glucosamine sulfate, and N2acetyl2 glucosamine. In vitro studies have shown that glucosamine stimulates the synthesis of proteoglycans and aggregated proteoglycan core proteins, inhibits lipopolysaccharide and interleukin (IL)-1-induced degradation of equine articular cartilage, inhibits IL-1β-induced activation of nuclear factor-κB (NF-κB) in human OA chondrocytes, COX- 2mRNA expression and protein synthesis, prostaglandin E2 production, inhibition of nitric oxide synthase expression, thus inhibiting nitric oxide production, and glucosamine also inhibits matrix metalloproteinase (MMP) and collagenase activity. Clinical studies have shown that glucosamine 1500 mg/d relieves patients’ symptoms and reduces further narrowing or increases the joint space, but some studies have shown that glucosamine is similar to placebo in the treatment of knee OA. Recently, Towheed et al. conducted a meta-analysis of 20 randomized controlled studies and showed a 28% increase in pain improvement with glucosamine treatment compared to placebo, but no statistical difference in WOMAC pain, function, or stiffness outcomes, and two of the randomized controlled studies showed that 3 years of glucosamine treatment delayed radiographic progression of OA. 3, other drugs: Other drugs such as metalloproteinase inhibitors, glycosidase inhibitors and cytokines or antagonists await further clinical trials to confirm. Surgery for osteoarthritis The main surgical procedures for the treatment of osteoarthritis are arthroscopic surgery and artificial joint replacement. Arthroscopic surgery: Arthroscopic surgery is useful for the removal or revision of debris causing mechanical impairment of the joint, meniscal fragments, and bone fragments, and for the removal of synovitis-causing inflammatory factors through intraoperative high-dose joint irrigation. Studies have shown that arthroscopic surgery is more effective in patients with stage I and II OA and in the relatively acute phase of symptom onset, as well as in patients with chronic progressive changes and in patients with advanced osteoarthritis who have improved after arthroscopic surgery. Arthroscopic procedures include the following: 1. Irrigation Because any arthroscopic procedure requires the use of irrigation to distend the joint capsule and remove surgically generated tissue debris to provide a good view, and because irrigation does not remove the causative mechanical factors, it is rarely used alone. The results of lavage alone have been inconsistent. In four cases of Grade III OA with lavage after microscopic examination alone, the average postoperative score improved by 47.5 points and the outcome was very satisfactory, but the number of cases was too small. 2. Clearance Clearance is the most used procedure and can be used at any stage of OA. The basic principle of cleanup is to remove the diseased tissue completely under the microscope and to preserve as much normal tissue structure as possible. It removes the mechanical factors that cause joint symptoms, such as degenerated and torn meniscus, rough cartilage surface, free body and bone flab that affect joint movement, and provides a smoother surface for joint movement; it also removes the hyperplastic synovium that causes knee pain, thus improving symptoms. The recent efficiency of arthroscopic debridement is reported to be around 70%, but the long-term results are not well reported. Zhang K., Department of Orthopedics, Peking University Third Hospital, followed up 33 cases of Grade III OA for 5 years and found that the functional score of the knee improved by 38.9 points after the procedure, which shows that the long-term efficacy of arthroscopic debridement for OA is also satisfactory. No secondary arthroscopy was performed on the patients during the follow-up, and the pathological status of the affected knee is unknown. It is also unknown whether the pathological vicious circle of the affected knee was broken after the cleanup and maintained in the state after the cleanup for a long time, but at least the symptoms of the affected knee were significantly improved and the function was improved after the operation. 3. Drilling Although arthroscopic debridement is very effective in appropriate patients, it is still not effective for the depletion and loss of articular cartilage and the exposure of subchondral bone. There is no regenerative ability of articular cartilage, and drilling or grinding of subchondral bone is to stimulate cartilage repair by drilling or grinding. su reported that there is no significant difference in the efficacy between the combined cleaning and drilling group and the control group of simple cleaning. In the 18 patients followed up by Zhang Ke of the Department of Orthopaedics, Peking University Third Hospital, the mean postoperative score was 67,4 months and the postoperative score was lower (78,9) than that of the clean-up-only group (88,9), with a significant difference. Drilling for severe OA did not improve the long-term outcome, and its effect was even inferior to that of the clean-up or lavage group alone, and there was no advantage in improving pain. The majority of OA patients with rest pain have elevated intraosseous pressure. Reducing intraosseous pressure and relieving knee pain symptoms by drilling is another original purpose of drilling. However, there are no reports in the literature on whether drilling several small 1.5 mm diameter holes in the lesion can actually reduce intraosseous pressure, and how long the reduced intraosseous pressure can be maintained after the holes are filled with repair tissue. The postoperative walking ability scores of the 18 drilled patients were lower than those of the clean-up group. At the very least, this suggests that drilling did not improve long-term postoperative outcomes. Both animal studies and secondary post-operative microscopic biopsies confirmed that the repair tissue obtained by drilling or grinding and shaping was fibrocartilage and not hyaline cartilage. Fibrocartilage contains only type I collagen, not type II collagen, and has low proteoglycan content, which is fundamentally different from hyaline cartilage in terms of tissue composition and structure, and does not possess the biomechanical properties of hyaline cartilage. Animal tests found that most of the repair tissues obtained by drilling began to fibrotic and disintegrate within one year. Drilling does not fundamentally reverse the lesion, and the repair group obtained in the short term is not maintained in the long term, which may be the reason why drilling does not improve the long-term outcome. Since drilling does not improve the long-term efficacy of cleanup, and the joint cannot bear weight for a longer period of time after drilling, which affects the quality of life, patients with total cartilage lesions and exposed subchondral bone can obtain better long-term efficacy by simply performing cleanup without drilling. Artificial joint replacement: Artificial joint replacement is one of the most important advances in the field of orthopaedic surgery in the 20th century. It has enabled some patients with advanced osteoarthritis, who used to rely on crutches or were unable to walk, to regain their standing and walking functions and partially or completely regain their ability to care for themselves, greatly improving their quality of life. It is now widely used at home and abroad as a mature treatment for severe joint lesions, and more than one million joint replacements are performed each year worldwide, and the service life of artificial joints has been greatly improved. The following are some of the most important factors in the prevention of osteoarthritis Prevention of osteoarthritis Proper exercise (such as swimming, walking, cycling, supine straight leg raise), weight reduction, avoiding high heels, protecting the joints from injury, reducing training that increases joint torque or overloads the joint surfaces (such as climbing mountains, stairs or squatting), and taking cartilage protectors can all have a preventive or slowing effect on osteoarthritis. Although medicine does not yet have the ability to reverse the course of osteoarthritis, comprehensive treatment can reduce pain and maintain or improve joint function. Treatment of osteoarthritis should focus on early diagnosis, early treatment and a long course of treatment. In other words, prevention and comprehensive treatment should be started when the patient is symptomatic and the joint cartilage is not yet significantly diseased, the joint space is not yet narrowed, and the bony bulge has not yet reached a visible level.