The association between body fat and rotator cuff tear: the influence on rotator cuff tear sizes

Background: Rotator cuff tear (RCT) has a multifactorial etiology. We hypothesized that obesity may increase the risk of RCT and influence tear size. Materials and methods: A case-control design study was used. We studied 381 consecutive patients (180 men, 201 women; mean age +/- standard deviation, 65.5 +/- 8.52 years; range, 43-78 years) who underwent arthroscopic rotator cuff repair. Tear size was determined intraoperatively. The control group included 220 subjects (103 men, 117 women; mean age +/- standard deviation, 65.16 +/- 7.24 years; range, 42-77 years) with no RCT. Body weight, height, and bicipital, tricipital, subscapularis, and suprailiac skinfolds of all participants were measured to obtain body mass index (BMI) and the percentage of body fat (% BF). For the purposes of the study, the 601 participants were divided into 2 groups by BMI (group A, BMI >= 25; group B, BMI < 25). The odds ratios (ORs) were calculated to investigate whether adiposity affects the risk of RCT. Data were stratified according to gender and age. Multiple linear regression analyses were applied to explore the association between obesity and tear size. Results: The highest ORs for both men (OR, 2.49; 95% confidence interval, 1.41-3.90; P = .0037) and women (OR, 2.31; 95% confidence interval, 1.38-3.62; P = .0071) were for individuals with a BMI >= 30; 69% (N = 303) of group A and 48% (N = 78) of group B had RCTs. Patients with RCT had a BMI higher than that of subjects with no RCT in both groups (P = .031, group A; P = .02, group B). BMI and % BF significantly increased from patients with a small tear (BMI, 27.85; % BF, 37.63) to those with a massive RCT (BMI, 29.93; % BF, 39.43). Significant differences were found (P = .004; P = .031). Conclusions: Our results provide evidence that obesity, measured through BMI and % BF, is a significant risk factor for the occurrence and severity of RCT. (C) 2014 Journal of Shoulder and Elbow Surgery Board of Trustees.