Evaluation of Rotator Cuff Augmentation of Proximal Humerus Fracture Fixation

Proximal humerus fractures represent one of the most common fractures in the elderly, and are increasingly treated with surgical fixation. Suture augmentation attaching the rotator cuff to the plate has been advocated to combat varus collapse and other associated complications. The objective of this study was to evaluate the contribution of rotator cuff augmentation to stability of proximal humerus fracture fixation. Twelve shoulder specimens from six cadavers underwent simulated two-part and three- part proximal humerus fractures. Matched specimens from the same cadaver were randomized to suture augmentation with locking plate fixation vs. locking plate fixation alone. Greater tuberosity fragment displacement was recorded during cyclic rotational strain of the glenohumeral joint. Greater tuberosity displacement in the two-part fracture model trended towards greater motion without suture augmentation, but did not reach statistical significance (0.032 + 0.012 mm vs. 0.213 + 0.109 mm, p = 0.130). In the three-part fracture model, there was a statistically significant decrease in fracture displacement in the presence of suture augmentation (0.068 + 0.025 mm vs. 2.392 + 0.373 mm, p < 0.001). No specimens demonstrated premature failure during cyclic loading. Suture augmentation of locking plate fixation of three-part proximal humerus fractures results in decreased fracture displacement than locked plating alone, during rotational stresses simulating in vivo rotator cuff deformation forces. (Journal of Surgical Orthopaedic Advances 31(2):119–122, 2022)

Key words: proximal humerus, locking plate, locked plate, suture augmentation, rotator cuff augmentation