Abstract
Objectives:
Body mass index (BMI) has been commonly studied in relation to hip and knee procedures, but the effect on shoulder instability procedures is less understood. This study aims to analyze BMI’s effect on clinical outcomes and recurrence rates following shoulder instability surgery.
Methods:
A retrospective study of patients who underwent operative treatment for shoulder instability between 2009-2023. Procedures included Bankart repair, Latarjet, distal tibial allograft, Hill-Sachs bone grafting, and remplissage. Patients were stratified into 3 cohorts by BMI: underweight or normal weight (U/NW, BMI ≤25 kg/m2), overweight (OW, BMI >25 to ≤30 kg/m2), and obese (BMI >30 kg/m2). Data collected included demographics, clinical outcomes, and functional markers.
Results:
A total of 429 patients (323 male, 106 female) underwent surgery to address recurrent shoulder instability. 167 patients were normal or underweight (22.4 ± 1.8 kg/m2), 158 patients were overweight (27.2 ± 1.4 kg/m2), and 104 patients were obese (35.6 ± 5.2 kg/m2). U/NW individuals had an average follow up of 1.9 ± 2.7 years, OW individuals had an average follow up of 2.3 ± 2.8 years, and obese individuals had an average follow up of 1.6 ± 1.8 years (p=0.048). Age was directly related to BMI at time of surgery (U/NW vs. OW vs. obese, 25.6 ± 7.9 years vs. 29.3 ± 10.1 years vs. 30.1 ± 11.7 years; p < 0.001). Obese individuals had a greater depression rate of 40%, compared to 23% and 22% for U/NW and OW, respectively (p=0.002). There was no difference in glenoid bone loss observed between the 3 groups. Preoperative external rotation (ER) (U/NW vs. OW vs. obese, 67 ± 22° vs. 60 ± 18° vs. 56 ± 18°; p < 0.001), postoperative ER (U/NW vs. OW vs. obese, 61 ± 19° vs. 60 ± 16° vs. 56 ± 16°; p < 0.045), preoperative internal rotation (IR) (U/NW vs. OW vs. obese, T10 vs. T11 vs. T11; p < 0.001), and postoperative IR (U/NW vs. OW vs. obese, T10 vs. T10 vs. T12; p < 0.001) differed between the 3 groups. No difference between preoperative and postoperative forward elevation was observed. Across all BMI cohorts, there was no difference observed in preoperative and postoperative strength measurements. There was no difference in revision survival rate at 2-years (U/NW 85% vs. OW 89% vs. obese 86%) or at 5-years (U/NW 59% vs. OW 76% vs. obese 73%; p = 0.197). At 2-years and 5-years, U/NW patients had a recurrence-free rate of 77% and 44%, OW patients 83% and 74%, and obese patients 64% at 2-years and 48% at 5-years (p=0.002).
Conclusions:
BMI is an important factor to recognize during preoperative planning in patients dealing with recurrent shoulder instability. OW individuals had a higher recurrence-free rate at 5-years, indicating UW/N and obese patients are at greater risk for instability recurrence, but there was no difference in reoperation rates between the groups. With slight differences in range of motion measurements, and no difference in strength measurements, stabilization surgery for recurrent instability is an effective treatment option for all patients regardless of BMI.
