Relationship Between Deltoid and Rotator Cuff Muscles During Dynamic Shoulder Abduction: A Biomechanical Study of Rotator Cuff Tear Progression

作者：Felix Dyrna, Neil S. Kumar, Elifho Obopilwe, Bastian Scheiderer, Brendan Comer, Michael Nowak, Anthony A. Romeo, Augustus D. Mazzocca, Knut Beitzel · 发表于：The American Journal of Sports Medicine · 年份：2018 · DOI：10.1177/0363546518768276 · 被引用次数：93 · 研究领域：Shoulder Injury and Treatment、Shoulder and Clavicle Injuries、Anesthesia and Pain Management

BACKGROUND: Previous biomechanical studies regarding deltoid function during glenohumeral abduction have primarily used static testing protocols. HYPOTHESES: (1) Deltoid forces required for scapular plane abduction increase as simulated rotator cuff tears become larger, and (2) maximal abduction decreases despite increased deltoid forces. STUDY DESIGN: Controlled laboratory study. METHODS: Twelve fresh-frozen cadaveric shoulders with a mean age of 67 years (range, 64-74 years) were used. The supraspinatus and anterior, middle, and posterior deltoid tendons were attached to individual shoulder simulator actuators. Deltoid forces and maximum abduction were recorded for the following tear patterns: intact, isolated subscapularis (SSC), isolated supraspinatus (SSP), anterosuperior (SSP + SSC), posterosuperior (infraspinatus [ISP] + SSP), and massive (SSC + SSP + ISP). Optical triads tracked 3-dimensional motion during dynamic testing. Fluoroscopy and computed tomography were used to measure critical shoulder angle, acromial index, and superior humeral head migration with massive tears. Mean values for maximum glenohumeral abduction and deltoid forces were determined. Linear mixed-effects regression examined changes in motion and forces over time. Pearson product-moment correlation coefficients ( r) among deltoid forces, critical shoulder angles, and acromial indices were calculated. RESULTS: Shoulders with an intact cuff required 193.8 N (95% CI, 125.5 to 262.1) total deltoid for...