Abstract
We report on six men and two women (mean age 42.5 years) who had sustained posterior dislocation of the shoulder in motor vehicle accidents (three), falls (two), equestrian accidents (two), cycling accidents (one) and in a fainting spell (one). In four patients, the dislocation was the only injury, but two had humeral shaft fractures, one a humeral neck fracture and the fourth a glenoid and humeral shaft fracture. The mean delay to diagnosis was 14 weeks (2 to 21).
In three patients a medical officer, a general practitioner and a radiologist missed the dislocations, but in five orthopaedic surgeons missed them. Four patients had only anteroposterior radiographs of their shoulder taken, one had anteroposterior and lateral scapular views, and three had anteroposterior and lateral radiographs of the humerus.
Four patients underwent hemi-arthroplasties and the other four open reduction and McLaughlin procedures.
Though rare, posterior dislocations are often missed. Careful examination, especially in the absence of external rotation, can eliminate this. In the presence of a fracture, a dislocation or injury to the joint above and below must be excluded. Anteroposterior and lateral scapular views alone are inadequate in trauma cases and an axillary or modified axillary view should be done. If there is any doubt, CT should be performed.
The abstracts were edited by Prof. M.B.E. Sweet. Correspondence should be addressed to him at the Department of Orthopaedic Surgery, Medical School, University of the Witwatersrand, 7 York Road, Parktown, 2193 South Africa
