Acute posterior dislocation of the shoulder: diagnosis

The authors describe the clinical and radiographic findings of posterior dislocation of the shoulder by examining 19 cases observed at the Rizzoli Orthopaedic Institute between 1981 and 1990; of the total number of cases, 16 were acute and 3 inveterate, equal to 1.7%. After analyzing the pathogenesis of the lesion, which was due to direct trauma, indirect trauma, or which occurred during an episode of convulsions, the authors call attention to the rareness of the lesion, and consequently the little amount of knowledge of the clinical and radiographic elements characterizing it. Three varieties are distinguished: subacromial (or retroglenoid), subglenoid, and subspinous. Finally, the results obtained with non-surgical treatment, which always allows for recovery of the joint relationships and complete functional recovery, are reported.