Diagnosis and treatment of hip impingement syndrome I. Concept: Hip impingement syndrome (femoroacetabular impingement, FAI) is a disorder caused by abnormalities in the anatomy of the hip joint that leads to impingement between the proximal femur and the acetabulum, resulting in degenerative changes in the glenoid labrum and articular cartilage of the hip joint and causing chronic pain in the hip joint. The range of motion of the hip joint, especially flexion and internal rotation, is limited and eventually develops into osteoarthritis of the hip joint. Hip impingement sign is an important factor that causes hip pain in young and middle-aged people, especially those who exercise a lot, and also causes early osteoarthritis. Pathogenesis: Femoral acetabular impingement may arise from an abnormal contact state of the femur and acetabulum, which is caused by a deformity of the proximal femur and (or) acetabulum. Repeated impingement of the femoral acetabulum causes a number of changes including pain in the anterior aspect of the hip, wear and tear degeneration of the acetabular labrum, and damage to the acetabular articular cartilage, ultimately leading to osteoarthritis of the hip joint. Deformities of the acetabulum such as developmental deformity, retroversion of the acetabulum, and acetabular entropion. Deformities of the proximal femur such as abnormal bony protrusions at the neck of the femoral head. Femoral acetabular impingement can also occur in patients with normal or near-normal hip anatomy and may arise from the occurrence of supra-physiological functional activity of the hip joint. Type: 1. Cam impingement type (CAM TYPE): The proximal femoral deformity is the main cause of cam-like impingement sign. The common deformity is an abnormal protrusion of bone at the anterior or anterior superior femoral neck junction. 2.PINCER TYPE:Acetabular deformity is the main cause of cam-like impingement sign. The common deformities are developmental deformity, acetabular retroversion, and acetabular invagination. 3, mixed type (MIXED TYPE ): most cases of FAI are mixed type. History: FAI usually occurs in middle-aged and young people with high activity. Patients often have intermittent chronic pain in the inguinal region, accompanied by limitation of hip movement, especially limitation of flexion and internal rotation, which may also occur after minor trauma. As the disease progresses, the pain may fire into the knee joint, and there may also be pain in the low back, sacroiliac joint, hip or greater trochanter, but usually not below the knee plane. A positive hip impingement test can be found by examination of the patient. Diagnosis: The current method of diagnosing FAI mainly relies on the patient’s medical history and imaging examinations, specifically X-ray, CT, MRI, among which MRI arthrography can observe the damage to the glenoid lip and acetabular cartilage. Treatment: The treatment of FAI is divided into non-surgical treatment and surgical treatment, and surgical treatment is divided into hip surgery and hip arthroscopic surgery. Non-surgical treatment: can be treated by improving the patient’s movement and taking anti-inflammatory and analgesic drugs. However, non-surgical treatment can only temporarily relieve the pain symptoms, but not the impingement factor, and therefore cannot stop the continuous progress of joint degeneration. Surgical treatment: Open hip surgery and minimally invasive hip arthroscopy are possible, but both types of surgery have their advantages and disadvantages, so you can choose the appropriate surgical treatment according to the patient’s condition.