Clinical manifestations and diagnosis】 1, the systemic manifestations of acute onset, chills, high fever, general discomfort, body temperature can be as high as 38.5 degrees ~ 40 degrees, the elderly and frail, the body temperature can be slightly lower. Poor health may show symptoms of sepsis. White blood cell count is increased, and blood culture may be positive. 2, local manifestations can be early hip joint pain, intensified when moving, even afraid or unwilling to move. The joint redness, swelling and fever are later, and the whole joint is painful, and the rotation activity is limited. Rolling test, 4-character test and Thomas’ sign (hip flexion deformity test) are positive. The joint is often in a flexion deformity position. 3.X-ray examination may show hip flexion, abduction, external rotation and swelling of the joint capsule in the early stage. In the middle and late stages, it is a typical manifestation of septic arthritis. 4.Arthrocentesis The puncture point is usually chosen 2cm below the midpoint of the inguinal ligament on the lateral side of the femoral artery, and the needle is inserted vertically. Bacterial culture can identify the strain of bacteria and determine the use of sensitive antibiotics. Because of the deep hip joint, thick surrounding muscles, complex anatomical structure and high pressure in the joint space, once septic inflammation occurs, the development is faster, and it is difficult to distinguish it from septic inflammation of surrounding tissues in the early stage, which makes early diagnosis difficult. Typical X-ray manifestations appear late and cannot be used as a basis for diagnosis, so arthrocentesis and joint fluid examination are particularly important. Differential diagnosis】 1, rheumatoid arthritis is one of the manifestations of rheumatic fever, mostly seen in adults, often occurs in the knee, shoulder, elbow, wrist and other large joints, the onset of most after the upper respiratory tract infection, appear wandering joint pain, swelling and fever and other manifestations of rheumatic fever. 2, rheumatoid arthritis is mostly seen in young adults, the onset of the disease is slow, often occurring in the small joints of the hands and feet and sacroiliac, and gradually involving the joints of the whole body. Initially, the diseased joints also show redness, swelling, pain and inconvenience, etc., for a long time, the joint deformity or ankylosis. Traumatic arthritis is caused by trauma or sustained chronic strain that causes degenerative changes in joint cartilage or the formation of bone spurs, manifesting as swelling, pain and movement disorders in the affected joints, easily occurring in weight-bearing joints, such as the shoulder, knee, ankle and other joints, and is common among athletes and young adults. 4, osteoarthritis is one of the most common joint lesions, osteoarthritis has many names, such as hypertrophic osteoarthritis, degenerative arthritis, degenerative arthritis, proliferative osteoarthritis or osteoarthrosis, all referring to a disease, domestic uniform use of osteoarthritis. Its prevalence increases with age and is more frequent in women than in men. The distal and proximal interphalangeal joints of the hand, knee, elbow and shoulder joints, and spinal joints are susceptible to osteoarthritis, while the wrist and ankle joints are less frequently affected. Osteoarthritis is caused by tissue degeneration and cumulative strain injury, mostly in obese and overweight middle-aged and elderly people, the most common sites are knees, fingers, neck, lumbar spine, etc. Symptoms are mainly joint pain, stiffness (pain will be reduced after light activity), and in severe cases, joint swelling, muscle atrophy, etc. 5, septic arthritis is often caused by the invasion of bacteria into the joint cavity, mostly in children and adolescents, often occurring in the hip joint, the main symptoms are local redness, swelling, pain, heat and dysfunction, as well as high fever and other symptoms of systemic toxicity. Regardless of the cause of arthritis or what type of arthritis, early diagnosis and treatment is necessary to avoid permanent joint dysfunction or even disability. The earlier the treatment, the better the effect, but sometimes there are difficulties in early diagnosis. For those suspected of acute septic arthritis of the hip, prompt treatment should be given as acute septic arthritis, and active examination should be conducted to avoid delaying effective treatment. Generally, high-dose broad-spectrum highly effective antimicrobial agents are used for treatment. Since most of the femoral head and femoral neck are located within the joint capsule, they are prone to osteomyelitis. Acetabular lesions also tend to spread directly to the iliac bone, causing iliac osteomyelitis. The hip joint is deep and surrounded by rich muscles, so trocar puncture is not easily successful, so early incision and drainage is required. Once the diagnosis is confirmed and the exudate in the joint is confirmed by puncture, it should be incised promptly. A posterior or lateral incision of the hip joint can be made, and after the joint capsule is incised, the intra-articular fluid is aspirated, flushed with a large amount of saline, and 2 silicone tubes of 3 mm in diameter are left in the joint cavity and fixed to the skin with sutures. The two tubes were connected to the drip bottle and suction device, respectively. The wound was sutured, and the antibiotic solution was used for closed flushing and suction. After surgery, the lower limb was placed on a functional exercise device for continuous passive movement or postoperative skin traction of the lower limb. During the recovery period, joint activities and functional exercises are feasible. Total hip arthroplasty, osteotomy and orthopedic surgery can be used for the treatment of sequelae. If the pain of old pathological dislocation is severe, joint fusion can be performed according to the need.