[Posterior Dislocation of the Shoulder with Compression Fracture of the Humeral Head. Our Experience with McLaughlin Procedure and Its Modification].

PURPOSE OF THE STUDY The purpose of this study is to remind of the specific features of diagnosis and therapy of dorsal dislocations of the glenohumeral joint to prevent frequent neglect or misdiagnosis during primary treatment. Also, we strived to present our experience and outcomes of posterior dislocation treatment by McLaughlin procedure and its modified version. MATERIAL AND METHODS We retrospectively evaluated 7 patients who had been treated at our department in the period 2015-2019 by McLaughlin procedure or its modification. The group consisted of 5 men and 2 women aged 33-79 years. In five patients, the dislocation occurred during an epileptic seizure, in two patients during an accident. The patients were treated by McLaughlin procedure or the Neer modification of McLaughlin procedure. The deltoideopectoral surgical approach was always used. Based on the preoperative planning, we decided, or intraoperatively changed our decision, as to whether mere transposition of the subscapularis is satisfactory or whether transposition of the lesser tuberosity to the defect, a bone graft and arthroplasty are necessary. Postoperatively, the operated limb was fixed for 6 weeks in neutral position, which was followed by rehabilitation. RESULTS We evaluated subjective and objective outcomes of the surgery, the radiological finding and in 2 patients also a control CT scan. The function of the shoulder was assessed using the Constant shoulder score and the OSIS scoring system. The resulting score: the mean OSIS was 55.7 points (92.8%) and the mean Constant score was 86.2 points (86.2%), which we regard as a very good result. All patients consider the surgery successful and are satisfied with the outcome. No patient reported recurrent dislocation. DISCUSSION When treating the posterior dislocation of the shoulder, vital is the shoulder reducibility and also the presence or the size of reverse Hill-Sachs defect. The transfer of the subscapularis tendon can be performed as an open procedure or arthroscopically. Inveterate irreducible posterior dislocation of the shoulder is quite a rare diagnosis, which is why even at our department the McLauglin procedure is performed in the order of units per year only. CONCLUSIONS The surgical solution of inveterate posterior dislocation of the shoulder is hardly ever uncomplicated. The reduction alone is often insufficient and some other way of shoulder stabilisation is necessary, often times addressing the humeral head defect. In our to date experience, the McLaughlin procedure or the Neer s modification is an elegant and safe method to treat posterior dislocation with a humeral head defect. The functional outcomes are very good and enable the patients to reengage in everyday activities. Thanks to this procedure shoulder joint arthroplasty can be avoided in younger patients. Nonetheless, in defects that are greater than 50% of the head the replacement is necessary. Due to frequently associated rotator cuff injuries, the most often procedure indicated by us is the reverse total shoulder replacement. Key words: posterior dislocation of the shoulder, reverse Hill-Sachs defect, McLaughlin procedure, Neer s modification.