RECOMMENDATIONS FOR THE TREATMENT OF PERSISTENT POSTERIOR DISLOCATION OF THE SHOULDER - A REVIEW OF THE LITERATURE

Three-hundred and twenty-nine cases of posterior dislocation of the shoulder documented in 300 articles published in the international literature are reviewed. They included 130 cases in which the duration of the dislocation was longer than 6 weeks and the dislocation could be classified as persistent primary dislocation. This group is the second largest group following that with acute primary dislocation. The mechanism of injury may be direct or indirect force: trauma, convulsions or electrocution are usually responsible for this type of dislocation, which often persists for longer than 6 weeks. Anatomically, 97.5% of dislocations are classified as subacromial. Posterior dislocation of the shoulder is commonly misdiagnosed on plain antero-posterior radiographs, and in over 50% of cases the diagnosis was missed on first examination. The typical signs of primary traumatic posterior dislocation of the shoulder are described. Management of persistent traumatic posterior dislocation of the shoulder depends on the size of the anterior Hill-Sachs lesion, the precipitating mechanism and the duration of dislocation. The results of 109 surgically and 24 conservatively treated dislocations of this type that have been published in the international literature are reviewed. Closed reduction is indicated in carefully selected cases with an anterior Kill-Sachs lesion under 15% of the size of humeral head (measured in the axillary view) that has been dislocation for less than 2 months. In most due to convulsions there was a distinct anterior Hill-Sachs lesion, which led to recurrence. In 83% of cases of convulsive origin there was a recurrence, whereas in the traumatic group redislocation occurred in 43%. In the group of 109 operative treated shoulders, isolated soft-tissue procedures have not been shown to produce good long-term results. In the case of a small anterior Hill-Sachs lesion, posterior bone block combined with anterior capsulotomy and stripping of the subscapularis muscle, as described by Augereau et al., gave good results in 5 of 6 cases. When a defect of 15-25% of the humeral head is present, subscapularis transposition is indicated. This method gave good or excellent results in 63% of cases seen after a mean follow-up time of 42 months. In 89% of the cases treated with the transposition to the lesser tuberosity as described by Neer the treatment was successful. Alternative treatment options in this group include the use of an autogeneous corticocancellous bone graft to fill the defect (Ahlers and Ritter), combined with a rotational osteotomy of the humerus if necessary. A hemiarthroplasty or total arthroplasty is indicated where these surgical treatments have been unsuccessful and when degenerative arthritis is present.