A Validated Three-Dimensional, Heterogenous Finite Element Model of the Rotator Cuff and The Effects of Collagen Orientation

Continuum mechanics-based finite element models of the shoulder aim to quantify the mechanical environment of the joint to aid in clinical decision-making for rotator cuff injury and disease. These models allow for the evaluation of the internal loading of the shoulder, which cannot be measured in-vivo. This study uses human cadaveric rotator cuff samples with surface tendon strain estimates, to validate a heterogeneous finite element model of the supraspinatus-infraspinatus complex during various load configurations. The computational model was considered validated when the absolute difference in average maximum principal strain for the articular and bursal sides for each load condition estimated by the model was no greater than 3% compared to that measured in the biomechanical study. The model can predict the strains for varying infraspinatus loads allowing for the study of load sharing between these two tightly coordinated tendons. The future goal is to use the modularity of this validated model to study the initiation and propagation of rotator cuff tear and other rotator cuff pathologies to ultimately improve care for rotator cuff tear patients.