How many cephalic locked screws are needed in valgus proximal humeral fractures?

Valgus impacted proximal humeral fracture is a specific type of fracture. The anatomic configuration of these fractures may favor union and reduce the risk of osteonecrosis, especially when the medial hinge is undisrupted [1], [2]. The best treatment is under debate [3], [4]. One of the treatment options is a plate with locked-angle screws. The idea of this construct is to stabilize the reduction so early rehabilitation can be started.

Locked-angle plates have shown biomechanical improvements in stabilizing proximal humeral fractures, providing a more secure fixation in the osteoporotic humeral head [5], [6]. Biomechanical studies show that the stability of the construct is proportional to the number of screws inserted in the head [7].

Most of the biomechanical studies refer to unstable fractures at the surgical neck, tested in axial load (varus load tests), which do not reproduce specifically a valgus impacted fracture.

They use humerus in which the tendons have been resected, therefore, they do not assess the effect of the rotator cuff, which counteracts the valgus instability of the head fragment when the greater and lesser tuberosities are anatomically reduced under the head fragment. Most of the models are two-fragment, unlike the case of valgus impacted humeral fractures, which usually have more fragments. Further, there are no biomechanical studies assessing the effect of indirect reduction using the plate as a buttress.

CITA DEL ARTÍCULO  Injury. 2017 Oct;48(10):2370-2372. doi: 10.1016/j.injury.2017.07.039. Epub 2017 Jul 31