Greater trochanteric kowtow is a clinical symptom of traumatic femoral head necrosis. So, what are the symptoms of greater trochanteric kowtow? How to identify and diagnose rotator cuff pain? Below, the introduction of several identification and diagnosis: 1, ankylosing spondylitis involving the hip joint: common in adolescent males, mostly bilateral sacroiliac joint involvement, which is characterized by HLA-B27-positive, the femoral head to maintain the rounded, but the joint space narrows, disappears or even fusion, so it is not difficult to identify. Some patients with long-term application of corticosteroids can be combined with necrosis of the femoral head, the femoral head can collapse, but often not serious. 2, acetabular dysplasia secondary osteoarthritis: CE angle less than 30 degrees, shenton’s now continuity interruption, femoral head parcel incomplete, acetabular line in the upper outer part of the femoral head, narrowing of the joint space, disappearance of the joint space, osteosclerosis, cystic changes, acetabular corresponding area similar changes, and the necrosis of the femoral head is easy to differentiate. 3.Synovitis: synovitis of various causes. Including pigmented villous nodular synovitis, non-specific synovitis, etc., in the X-ray can be seen in the acetabulum and the femoral head edge bone erosion, MRI shows extensive lesions with joint effusion, etc., should be identified. 4. Rheumatoid arthritis: mostly seen in women, the femoral head remains round, but the joint space becomes narrow and disappears. Common femoral head joint surface and acetabular bone erosion, identification is not difficult. 5. Middle and advanced osteoarthritis: when the joint space is mildly narrowed and subchondral cystic degeneration occurs, it may be confused, but its CT manifestation is sclerosis with cystic degeneration, and the MRI changes are mainly low-signal, so it can be differentiated accordingly.