Gluteal myoclonus is a clinical syndrome caused by degeneration and contracture of gluteal muscle and its fascial fibers, which leads to dysfunction of hip joint adduction and internal rotation, and thus manifests the characteristic gait and signs.It was firstly reported by Valderrama in 1969, and firstly systematically reported by Ma Chengxuan in 1978 in China. From October 1992 to August 2006, 56 cases of gluteal myoclonus were treated in our hospital with satisfactory efficacy, which are reported and analyzed as follows. 1, clinical information 1.1 General information of this group of 56 cases, male 27 cases, female 29 cases, age 7 to 16 years old, the average age of 11 years. There were 20 cases of unilateral and 36 cases of double testing. There were 48 cases with a history of receiving repeated intramuscular injections of drugs into the buttocks. 1.2 Clinical manifestations The patients all showed abnormal squatting posture and characteristic gait, and the children with bilateral lesions had a figure-eight gait when standing or walking, which was more obvious when running. When sitting, the legs could not be brought together; when squatting, the knees had to be separated, making an outward circling movement, which was typical of the frog position. Hip flexion was limited in the neutral position, and hip flexion could only be accomplished by abduction and external rotation. In 56 cases, skin depression was seen above the outer buttocks, and strips were palpable under the skin and extended down to the greater trochanter, and the sitting cross-leg test and parallel-leg hip flexion test were both positive.There was no skeletal lesion in the X-ray examination. 1.3 Surgical method: the patient was lying on the side, the operation side was upward, routine disinfection and spreading of towel, longitudinal incision was made in the middle of the stripe 2cm above the greater trochanter, and extended upward for 3-5cm, intraoperatively, we could see that the gluteal fascia was degenerated and thickened, and part of gluteal muscle was deformed and contracted, which was tense and hard, and was white in color. The mild lesions were in the form of fibrous strips, and the severe ones were in the form of fibrous scar plates. The cumulative extent of the lesions could be 2-7 cm wide and the depth could reach the whole muscle layer. Fibrous contracture bands are not clearly demarcated from the normal muscle and overlap each other. Cut off or excise part of the contracture band, the hip joint can be internally adducted, and then do the hip flexion test, if there is no limitation of internally adducted and hip joint popping, it means that the loosening has been complete, and the same method is used to deal with the contralateral side. 1.4 The treatment results of all cases were followed up for 1 to 9 years, average 4 years, 50 patients’ gait and hip joint function returned to normal or close to normal, 6 cases had poor hip abductor muscle strength, no recurrence cases, the good rate of 89.2%. 2.Discussion 2.1 Etiology and pathogenesis Ma Chengxuan believes that when hip injection is carried out, the drug enters the gluteal muscle and then spreads along the muscle bundle gap in the direction of the muscle spacing, and due to repeated injections, the stimulation of the drug and needle puncture injury can cause chemical and traumatic myofibroblastic stromal inflammation, secondary to the proliferation of fibrotic tissues, and finally the formation of hard fibrous scar contracture bands. According to Chen Jinying, the soft tissue of the gluteal muscle of children is thin, when injected with large volume or small volume multiple injections, due to the slow absorption of drugs, coupled with drug-responsive inflammatory edema, resulting in increased pressure in the gluteal interosseous space, muscle blood flow obstacles, due to ischemia, resulting in aseptic necrosis, degeneration and fibrosis. This is the so-called injection factor theory. The history of repeated gluteal injections in 48 cases in this group also supports this view. In addition, some people reported that there are genetic factors, susceptibility factors. Huang Yaotian summarized as six types: (1) injectable gluteal myoclonus (2) idiopathic gluteal myoclonus (3) gluteal myoclonus complicated by congenital hip dislocation (4) gluteal myofascial compartment syndrome with postoperative gluteal myoclonus (5) infectious gluteal myoclonus (6) gluteal myoclonus manifested by multiple myofascial contractures. In short, the etiology is very complex. 2.2 Surgical method and main points of surgery, we usually incise the iliotibial fascia on the surface of gluteus medius muscle 2cm above the greater trochanter, and then backward to the edge of gluteus maximus muscle, then the gluteus maximus muscle – iliotibial fascia inferior interspace behind the greater trochanter of the femur will be clearly revealed, and we can use the index finger to extend into it as a guide to pick up contracture tissues with vascular forceps to loosen them one by one. Surgical release of all contractures and degenerative tissues should be performed without residual contracture tissue, and it is important to achieve a satisfactory release on the operating table, rather than relying on postoperative functional exercises. On the operating table, the range of motion of the hip joint should meet the following requirements: the hip joint should be internally adducted and internally rotated at about 25 degrees, flexed at more than 120 degrees, and there should be no bouncing of the extended hip joint when the hip joint is extremely internally adducted and internally rotated. Drainage strips were placed and removed after 24 hours. 2.3 Reasons for surgical failure In this group, there were 6 cases with poor postoperative hip abduction muscle strength, abnormal walking gait, obvious when running. Reviewing the medical records, it was found that all 6 cases were patients with heavy contracture and contracture of gluteus medius and gluteus minimus in the surgical records, which were all released during the operation. The angle between the fiber direction of the gluteus minimus and the axis of the lower limb was smaller than that of the gluteus medius, and according to the principle of leverage, it was known that the force of the gluteus minimus to abduct the hip joint was greater than that of the gluteus medius, therefore, the poor abduction force of the hip joint after the operation resulted in an unstable gait, which affected the efficacy of the treatment. In addition, some authors have reported cases of unequal length of both lower limbs caused by gluteal myoclonus, which were misdiagnosed as bilateral femoral imbalance and mis-treated or aggravated postoperatively by unilateral release, but we haven’t encountered such cases yet. 2.4 Importance of postoperative functional exercises Although we emphasized the necessity of complete release during surgery above, postoperative functional exercises are also important. After surgery, both lower limbs are fixed by flexing the hips, bending the knees and keeping the knees together, and after the third day, they get out of bed to perform one-word walking exercise and knee-knee squatting action, and after five days, they practice cross-legged walking. This can prevent adhesion and achieve good postoperative results.