The incidence of posterior instability of shoulder joint was significantly lower than that of anterior instability, but the clinical diagnosis and treatment was difficult, and the misdiagnosis and missed diagnosis rate were high. Its etiology, clinical manifestation and treatment strategy are totally different from the anterior instability. Therefore, the deep understanding of the anatomical structure around the shoulder joint, the mastery of the examination method, and the classification of the shoulder instability based on the anatomy and injury mode are of great importance to improve the accuracy of diagnosis. CT three-dimensional reconstruction is helpful to evaluate the defect of humeral head and glenoid bone, and MRA is helpful for the accurate diagnosis of posterior glenoid lip and joint capsule. The treatment was divided into conservative treatment and surgical treatment. Conservative treatment is recommended for muscular instability. Surgical treatment is recommended for traumatic and dysplastic instability. Different operative methods should be performed according to the injury of glenoid side or humeral head side. According to the condition of bone defect, soft tissue operation, bone grafting or osteotomy were performed to reconstruct the posterior stable structure of the glenoid injury; according to the area of the anterior bone defect, bone grafting or subscapular muscle packing were performed to the head of humerus defect. The former has the advantages of short learning curve and firm fixation, while the latter has the advantages of minimally invasive operation and the ability to observe the lesions from multiple angles and accurately control the location of bone masses. This paper summarizes the above problems.





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