Poster 184: Demographics and Outcomes of Shoulder Instability in Individuals with Elevated Body Mass Index

Objectives: Traumatic shoulder dislocations in the adolescent, active adult, and elderly have been well studied. However, to our knowledge, no specific study has investigated the characteristics and outcomes of anterior shoulder dislocations in morbidly obese individuals. The objective of this study is to describe shoulder dislocations in patients with body mass index (BMI) greater than 40. Methods: A retrospective chart review was performed to identify patients 18 years of age and older with a BMI greater than or equal to 40 who presented with a shoulder dislocation within a single institution from 2000-2020 were included in this study. Patients who had a BMI of less than 40, sustained a periprosthetic shoulder dislocation, and patients who were pregnant were excluded from this study. Dislocation pattern, associated injuries, treatment modalities, and associated complications were recorded. Complications were defined to include recurrent instability as demonstrated by a single recurrent dislocation event, infection, arthrofibrosis, and associated neurovascular injury. Results: Seventy-seven patients were included in our study. Fifty-two patients (67.5%) were female. Average age was 47.95 ± 2.06 (range 18-81), with average BMI of 45.01 ± 5.67 (range 40-78). Mean follow up for our patient cohort was 411.5 days (1.13 years). Sixty-five dislocations (84%) were due to a ground level fall whereas 8 (10%) were due to assault and 4 (5%) were due to a motor vehicle collision (MVC) (p<0.01). There was a significant increase in the number of patients with BMI greater than 40 presenting per year (r 2 = - 0.831, p < 0.01) over the past 20 years. In addition, there was also a significant increase in the average BMI per year in this population (r 2 = 0.504, p=0.028). Fifteen patients (19.5%) experienced at least one recurrent dislocation episode, with average time to recurrent dislocation of 449 days (1.23 years). Hill-Sachs lesions were the most common associated injury (p=0.03). Bankart lesions were the only associated injury that were found to be associated with an elevated BMI (p = 0.04), Nine patients (11.7%) sustained an associated neurologic injury which was found to have no association with BMI. There were 56 patients (72.7%) who were managed non-operatively and 21 patients (27.3%) who underwent surgical intervention. One patient failed nonoperative management and arthroscopic stabilization, going on to require shoulder arthrodesis and biceps tenodesis. They subsequently developed a post-operative infection necessitating revision arthrodesis. Conclusions: Over time, there has been an increase in shoulder dislocations in morbidly obese individuals in the United States, alongside an overall increase in the average BMI of patients who present with shoulder dislocations. These injuries most commonly happen due to low energy mechanisms and can be associated with Bankart lesions and associated neurologic injuries. There was a recurrent dislocation rate of 19.5%, which is consistent with this age cohort. As the current trend continues it will become increasingly important to better understand these injuries. Morbidly obese patients may incur higher health care costs and resource expenditure to treat such injuries. In addition, appropriate patient education and outcome expectations for nonoperative and operative treatment should be provided given the high risk of recurrent dislocations in this patient population.