Posterior fracture-dislocation of the shoulder

Background: Posterior dislocations of the shoulder are rare and comprise between 1% and 4% of all reported cases of shoulder dislocations. Most of them are caused by seizures. Patients and Methods: Between 1990 and 2000, 17 patients with 20 posterior fracture-dislocations were treated in the authors' institution. The group consisted of twelve males and five females with a mean age of 50 years (range 29-77 years). In three patients, posterior four-part fracture-dislocations were found, one of them bilateral. One of the four-part fractures was treated by minimal osteosynthesis, in two patients with three four-part fractures, hemiarthroplasties were performed. In two patients with posterior locked dislocations, closed reduction under medical sedation proved successful. The others were reduced under general anesthesia. Results: During the follow-up period of 2.5 years on average, no recurrent dislocation was observed. The worst functional outcome was seen in patients after hemiarthroplasty. One patient was lost to follow-up. Results were evaluated according to the score by Rowe & Zarins. 16 patients with 19 shoulders afflicted could be followed up. In 15.8% (n = 3) excellent results were found, in 31.6% (n = 6) the outcome was good and in 36.8% (n = 7) fair, and in 15.8% (n = 3) poor results were observed. Conclusion: If the humeral head's impression zone encounters < 20% of the articular surface, closed reduction is possible. If the impression zone is bigger, open reduction, fixation of the subscapular tendon into the defect, and fixation of the lesser tuberosity are recommended. In patients with subcapital fracture-dislocations of the humeral head, hemiarthroplasty should be performed. © Urban & Vogel.