RESUMO
Objective: The primary goal of this study is to evaluate the relationship between Body Mass Index (BMI) and muscle atrophy in individuals with rotator cuff tears. Methods: This study consists of patients with rotator cuff tears identified by MRI from two independent cohorts, the Rotator Cuff Outcomes Workgroup (ROW) and the Multicenter Orthopaedic Outcomes Network (MOON). Presence of atrophy (yes/no) and severity of atrophy (as an ordinal variable) were assessed on MRI by expert physicians. We used multivariable regression models to evaluate the relationship between BMI and muscle atrophy while adjusting for age and sex in each study, conducted sensitivity analyses for full-thickness tear and combined results using inverse variance-weighted meta-analysis. Results: A total of 539 patients (MOON=395, ROW=144) from the combined cohorts had MRI data available on muscle atrophy. Among these patients, 246 (46%) had atrophy of at least one of the muscles of the rotator cuff and 282 (52%) had full-thickness tears. In meta-analysis across both cohorts, each 5 kg/m2 increase in BMI was associated with a 21% (aOR=1.21, 95% CI=1.02, 1.43) increased odds of having muscle atrophy among individuals with any tear size, and 36% (aOR=1.36, 95% CI=1.01-1.81) increased odds among individuals with full-thickness tear. Conclusions: Higher BMI was associated with significantly higher odds of muscle atrophy in patiens with rotator cuff tears. More study is needed to unders1tand why and how this relationship exists, as well as whether interventions to reduce BMI may help improve outcomes for these patients. Level of Evidence: III.
RESUMO
BACKGROUND: Women are at substantially greater risk for anterior cruciate ligament (ACL) injuries than are men. PURPOSE: To conduct a systematic review and meta-analysis of the literature to clarify the effect of the menstrual cycle and contraceptives on the laxity of and noncontact injuries to the ACL. STUDY DESIGN: Systematic review; Level of evidence, 4. METHODS: Searches were conducted using MEDLINE (1946-August 2016), the Cochrane Library Database, clinical trial registries, and related reference lists. Search terms included athletic injuries, knee injuries, ligaments, joint instability, menstrual cycle, ovulation, hormones, and contraceptives. Investigators independently dually abstracted and reviewed study details and quality using predefined criteria and evaluated overall strength of evidence using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) criteria. RESULTS: Twenty-one studies totaling 68,758 participants were included: 5 on the menstrual cycle and ACL injury, 7 on hormonal contraceptives and ACL injury, as well as 13 on menstrual cycle and ligament laxity. Four of 5 studies of women not using hormonal contraception indicated that the luteal phase was the least associated with ACL injuries. The 2 largest and highest quality studies on hormonal contraceptives suggested that hormonal contraceptives may be protective against ACL injury. Six of 12 studies on ACL laxity provided quantitative data for meta-analysis, finding significantly increased laxity during the ovulatory phase compared with the follicular phase. CONCLUSION: The literature suggests an association between hormonal fluctuations and ACL injury. Recent studies have suggested that oral contraceptives may offer up to a 20% reduction in risk of injury. The literature on ACL injuries and the menstrual cycle has more than doubled over the past decade, permitting quantitative analysis for the first time. However, the overall strength of this evidence is low. Promising potential directions for future research include long-term observational studies with ongoing hormonal assays and large interventional trials of follicular suppression, including newer hormonal methods.
