Shoulder instability and associated shoulder injuries in patients with epilepsy.

backgroundThe epidemiology and characteristics of shoulder dislocations in the context of epileptic seizures, as well as treatment recommendations, have so far been not described in detail in the literature. The aim of this retrospective study is to document the epidemiological characteristics and treatment options of shoulder instabilities occurring during epileptic seizures, as well as to quantify associated injuries.

methodsAs part of a retrospective analysis, 72 shoulders in 56 patients at our clinic were evaluated who sustained shoulder dislocation during an epileptic seizure. An analysis of the epidemiology and key characteristics was conducted. Sectional imaging including computer tomography scans and/or magnetic resonance imaging of all patients were independently analyzed at different time points by two raters (A.P. and H.G.) using OsiriX™ (Geneva, Switzerland) for glenoid defects as well as the Hill-Sachs lesion (HSL) and the reverse HSL (RHSL). When present, surgical treatment modalities were analyzed.

resultsThe cohort had a mean age of 37 ± 16 years; 12 were female (21%) and 44 were male (79%). A total of 72 shoulder dislocations were identified: 60% anterior (43/72), 30% posterior (22/72), and 10% bidirectional (7/72); 51% were first-time dislocations (37/72) and 49% recurrent (35/72). Radiological imaging suitable for quantitative defect analysis was available for 47 shoulders, including 30 anterior and 17 posterior dislocations. The anterior glenoid defect size of patients with anterior dislocation averaged 11% (± 8%) and the mean posterior glenoid defect size of patients with posterior dislocation was 7% (± 6%). 16 of the 30 anterior dislocations and three of the 17 posterior shoulder dislocations were recurrent. Significant differences between first-time and recurrent dislocations were found in HSL width (13 mm vs. 15 mm; p = 0.008), HSL length (24 mm vs. 29 mm; p < 0.001), posterior glenoid defect size (5% vs. 13%; p = 0.04), and reverse HSL γ-angle (114° vs. 84°; p = 0.003). Fractures occurred in 46.4% of patients (26/56), all involving the proximal humerus, three patients also sustained a glenoid fracture. 62.5% of injuries were treated surgically (45/72). Surgical techniques included soft tissue stabilization (26.7%; 12/45), bony augmentation (24.4%; 11/45), arthroplasty (4.4%; 2/45), and humeral open reduction and internal fixation (44.4%; 20/45).

conclusionIn patients with epilepsy, shoulder dislocations predominantly occur during generalized seizures, with anteroinferior dislocations being the most frequent, while posterior dislocations are significantly more prevalent compared to the general population. Recurrent dislocations were associated with significantly larger humeral and posterior glenoid defects, indicating progressive bone loss. Approximately half of all injuries involved proximal humerus fractures, with more than half requiring surgical intervention. LEVEL OF EVIDENCE: IV.