Importance of Calcar Comminution and Screw Length in Proximal Humerus Fractures Treated With Locking Plate Fixation

While proximal humerus fractures are relatively infrequent and the majority are amenable to non-operative treatment, open reduction with internal fixation remains a surgical mainstay [1,2]. With the advent of locking fixation, the majority of proximal humerus fractures requiring surgery are treated with locking plates. Biomechanical studies have demonstrated that locked plating is superior to intramedullary fixation, conventional or blade plating in two and three part proximal humerus fractures [3,4]. Despite the increased stability and use of locking fixation, loss of reduction remains a post-operative problem in osteoporotic bone with comminuted fractures [5]. Presently we hypothesized that: 1) Medial comminution of the calcar region is a determinant of fracture and fixation stability; and 2) Greater stability and increased resistance to varus deformity is gained through use of locking screws that cross the inferior surgical neck and penetrate the humeral head, i.e., the calcar region of the humerus.