Local anatomy】The iliotibial fascia is the thickest fascia in the body and is composed of the broad fascial tensor fasciae and the gluteus maximus tendon membrane. The vastus lateralis muscle starts from the anterior superior iliac spine and 2.5 cm before the outer lip of the iliac crest, and is located between the suture and gluteus medius muscles. The muscle belly is shuttle-shaped, with fibers traveling downward and slightly backward, and migrates into a tendinous tissue above the greater trochanter, forming the beginning of the anterior superior part of the iliotibial bundle. The gluteus maximus muscle starts from the posterior superior iliac spine to the tip of the coccyx, with fibers running parallel and oblique outward, and the superior portion of the tendon membrane at its stop forms the beginning of the posterior inferior portion of the iliotibial bundle, and the posterior inferior portion of the tendon membrane at its stop ends at the gluteus ramus. There is a bursa between the iliotibial bundle and the greater trochanter, and a subcutaneous bursa superficial to the iliotibial bundle; trauma or repeated friction can cause bursal inflammation. The lower end of the iliotibial bundle is divided into two parts, the main part ends at the Gerdy node on the lateral side of the upper tibia and a small part of the oblique tendon fibers ends at the lateral edge of the patella. Therefore, the popping sensation of the greater trochanter due to contracture of the iliotibial bundle can sometimes be transmitted to the lateral side of the knee and be mistaken for a popping of the lateral meniscus of the knee. The cause of gluteus maximus and iliotibial tract contracture is thought to be congenital. Currently, most believe that it is caused by fibrous scarring of the muscle tissue after intra-gluteus maximus drug injection. In individual patients, it may be related to repetitive friction during sports training. It is also often combined with inflammation of the subacromial bursa of the iliotibial tendon, and in some patients, the contracture may also involve the gluteus medius fascia. The main clinical manifestations in patients with snapping hips are: (1) snapping in the greater trochanteric region of the femur, combined with bursitis is localized pain and tenderness. Flexion of the hip and knee, internal rotation of the hip, and then straightening the lower limb will induce the popping and popping sensation. Patients can also actively induce snapping, and individual patients may not have snapping signs. The hip joint is limited in internal contraction, internal rotation and flexion. (2) Abnormal gait with external rotation and abduction of both lower limbs. (3) The lower extremities cannot be completely brought together in the standing position or with difficulty. (4) The knees cannot be brought together in the sitting position, and the knees cannot be overlapped (crossed legs). Cannot sit up with straight legs in the prone position. (5) Cannot squat with knees together. (6) In some patients, the contracture band can be palpated along the gluteus maximus muscle, and it is more obvious when the hip is internally retracted. (7) “Pseudo-extrinsic hip” can be seen in the pelvic orthopantomograph. (8) If the degree of contracture is different bilaterally, pelvic tilt and scoliosis may occur. Indications for surgery] In general, if there is no significant impact on daily life and sports, and there are only symptoms such as popping and no pain, surgery is not necessarily needed. If the symptoms are obvious and have an impact on life and sports, surgery can be considered. Athletic patients should consider surgery if the disorder affects training or the quality of movement. There is no conservative treatment method with definite efficacy. Surgical procedures and intraoperative considerations] Surgery can be performed by incision or arthroscopic release. Arthroscopic release: In recent years, the development of endoscopic technology has made it possible to perform this procedure under the arthroscope, which has been increasingly used in clinical practice because of the small trauma, positive results and safe operation. The advantages are: (1) The operation is performed under arthroscopic surveillance, with a clear field of view and clear identification of blood vessels and nerves, and the working area is far from the anatomical parts of the sciatic nerve, superior and inferior gluteal nerves, avoiding damage to the sciatic nerve, superior and inferior gluteal nerves. (2) With radiofrequency vaporization, only 1 mm of the surface layer is used, and there is no damage to the surrounding tissues, and the hemostatic effect is good. Without extensive stripping of muscle tissue injury is small, bleeding is less, and the formation of local hematoma can be effectively prevented. (3) The surgical incision is small, the operation time is short, the postoperative tissue reaction is light, which is conducive to early functional exercise and rehabilitation. Postoperative treatment and rehabilitation] Negative pressure drainage is removed 24-48 hours, postoperative bed rest in free position, pay attention to the bleeding of the diseased area and the elastic bandage tightness. Negative pressure drainage is removed in 24-48 hours. After 48 hours of unilateral surgery, you can walk on the ground with the help of crutches, but excessive activities are not recommended within 3 days after surgery. Walking and hip flexion (sitting position) with single crutch or decubitus can be done 8 days after surgery. About two weeks after surgery, the stitches were removed and the hip was encouraged to be inwardly flexed (crossed legs) without the use of crutches. Four weeks after surgery, athlete patients can gradually resume training.