Primary anterior dislocation of the shoulder

Abstract

The authors were unable to find authoritative or documented evidence that any form of conservative treatment prevented all dislocations of the shoulder from recurring. The trends indicated by this preliminary study suggested, on the contrary, that treatment of the primary episode was of little importance and that the site and nature of the primary pathologic disorder was of utmost importance in determining whether or not recurrences would take place.

The incidence of recurrence was 90 per cent in patients under twenty years of age, 60 per cent in patients between twenty and forty and only 10 per cent in patients over forty. This would appear incompatible with theories that recurrence depends upon specific details of treatment or mechanisms of injury. It might be postulated that one explanation of this age incidence depends upon the balance of strength between the anterior and posterior Joint supports at different ages. In the young both the tendon cuff and the humeral head are strong but also supple and elastic as compared to those in older persons in whom both become progressively weaker and more brittle. This fact of attrition may predicate that during youth the glenohumeral ligaments are the weaker components of the joint supports which give way first under stress. In any event recurrence of a traumatic lesion depends essentially upon rupture or avulsion of these ligairents. Comparable damage to the ligamentous supports of most other larger Joints warrants early operative repair since neither in the shoulder nor any other joint do such lesions often heal in a functionally satisfactory manner. It is submitted, therefore, that in the appropriate age groups these avulsed or ruptured glenohumeral ligaments deserve early operative repair as the only reasonably sure method of achieving healing and preventing the great majority of recurrent dislocations.

There was definite evidence that the posterior supports of the Joint were the weaker component which gave way to allow dislocation in about 70 per cent of all patients past the age of forty. Was this because the attritional changes of advancing years had made both tendon cuff and tuberosity weaker and more brittle? Such dislocations in theory should not and, in fact, did not recur but were prone to nerve injuries, delay in recovery and permanent disability of some degree resulting from internal derangement of the subacromial mechanism. This syndrome proved more common and disabling than recurrent dislocation but could be anticipated consistently by roentgenographic demonstration of residual tuberosity displacement or clinical evidence of cuff damage. Early identification and operative repair proved by far the best treatment for properly selected lesions of this type with operative revision following the establishment of late symptoms a poor second choice.