1.What is dense osteoarthritis? Dense osteoarthritis generally refers to dense osteoarthritis of the sacroiliac joint, which occurs in young and middle-aged women, and most patients have no clinical symptoms and develop insidiously, and are only discovered unintentionally when taking X-rays. A few patients may have pain in the lower back and sacrum (buttocks), mostly chronic, intermittent soreness and vague pain, which may spread to one or both buttocks and the back of the thigh, but does not radiate in the direction of the sciatic nerve, aggravated by walking, standing, weight bearing and exertion, and relieved by rest. x-ray or CT examination may find that the iliac surface of the sacroiliac joint is a dense zone of bone with uniform dense white edges and clear bone trabeculae, but the sacroiliac The joint surface is bright and neat, without bone destruction, and the joint gap is neat and clear. 2. Why is dense osteitis misdiagnosed as ankylosing spondylitis? The most common symptom of ankylosing spondylitis is also lower back pain and/or hip pain, and the sacroiliac joint can also show osteosclerosis on X-ray or CT, which is the main reason for misdiagnosis. However, the pain characteristics of these two diseases are different: lower back pain in ankylosing spondylitis is often accompanied by morning stiffness, which decreases after activity but worsens after rest, often with painful awakening at night and difficulty in turning over; lower back pain in dense osteosclerosis may decrease after rest and worsen after increased physical work or prolonged walking. The sacroiliac joints of these two diseases also have characteristic differences on X-ray or CT films: in ankylosing spondylitis, the sacroiliac joint surface generally has destructive changes and the joint space can be narrowed, etc.; in dense osteitis, the sacroiliac joint surface is smooth (i.e., no destruction) and the joint space is generally normal. For an experienced physician, these two diseases are easily distinguished on x-ray or CT film. In addition, ankylosing spondylitis occurs in young men, and more than 90% of patients have a positive HLA-B27 test, and increased blood sedimentation is more common. Of course, in rare cases the two diseases can exist together. 3.Why do you have osteomalacia? More than 90% of patients with this disease are married menstruating women, and it is more common in late pregnancy, especially after childbirth, or after chronic infection of the urinary tract or female adnexa, or other infections in the pelvis. Trauma to the hip-sacral area can also trigger or cause the disease. In other words, pregnancy, childbirth, trauma and pelvic infection are the main causes of this disease. 4.How to treat dense osteitis? The disease is self-limiting and has a good prognosis, i.e. there are usually no sequelae, so only symptomatic treatment is needed clinically and over-treatment should be avoided. In mild cases, pain can be improved by rest, physical therapy, acupuncture, etc. In moderate to severe cases, anti-inflammatory and pain-relieving drugs or local closure treatment can be given.