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

Three-hundred and twenty-nine cases of posterior dislocation of the sh oulder documented in 300 articles published in the international liter ature are reviewed. They included 130 cases in which the duration of t he dislocation was longer than 6 weeks and the dislocation could be cl assified as persistent primary dislocation. This group is the second l argest group following that with acute primary dislocation. The mechan ism of injury may be direct or indirect force: trauma, convulsions or electrocution are usually responsible for this type of dislocation, wh ich often persists for longer than 6 weeks. Anatomically, 97.5% of dis locations are classified as subacromial. Posterior dislocation of the shoulder is commonly misdiagnosed on plain antero-posterior radiograph s, and in over 50% of cases the diagnosis was missed on first examinat ion. The typical signs of primary traumatic posterior dislocation of t he shoulder are described. Management of persistent traumatic posterio r dislocation of the shoulder depends on the size of the anterior Hill -Sachs lesion, the precipitating mechanism and the duration of disloca tion. The results of 109 surgically and 24 conservatively treated disl ocations of this type that have been published in the international li terature are reviewed. Closed reduction is indicated in carefully sele cted cases with an anterior Kill-Sachs lesion under 15% of the size of humeral head (measured in the axillary view) that has been dislocatio n for less than 2 months. In most due to convulsions there was a disti nct anterior Hill-Sachs lesion, which led to recurrence. In 83% of cas es of convulsive origin there was a recurrence, whereas in the traumat ic 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 Hi ll-Sachs lesion, posterior bone block combined with anterior capsuloto my 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 afte r 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 t reatment was successful. Alternative treatment options in this group i nclude the use of an autogeneous corticocancellous bone graft to fill the defect (Ahlers and Ritter), combined with a rotational osteotomy o f the humerus if necessary. A hemiarthroplasty or total arthroplasty i s indicated where these surgical treatments have been unsuccessful and when degenerative arthritis is present.