Monoaxial versus polyaxial locking systems: a biomechanical analysis of different locking systems for the fixation of proximal humeral fractures

Mono- versus polyaxial locking plates in distal femur fractures: a prospective randomized multicentre clinical trial

“…In a biomechanical study using synthetic distal femurs, no differences in stiffness, load to failure and mode of failure were detected between the LISS® and NCB®-DF groups [10]. In a biomechanical study performed in formalin-fixed proximal humerus bone, the same results in the cyclic tests, the fatigue tests and the crash tests were found [20]. In a randomized prospective study using radiographic evaluation, similar results were detected for secondary varus displacement and screw cut-out using mono-vs. polyaxial angular stable plating of displaced proximal humeral fractures [21].…”

The Humerusblock NG: a new concept for stabilization of proximal humeral fractures and its biomechanical evaluation

“…Most studies [9,10,31] include uni-axial cyclic loading and load-to-failure testing to determine fixation stability. However, in clinical practice implant cut out or postoperative varus deformation do not usually occur after a single trauma (in accordance with failure load), but more likely after first physio-therapeutic mobilization [35].…”

“…Several angular stable locking devices, such as anatomical pre-shaped plates and intramedullary nails have a relative high stiffness [9,10,31] compared to the humeral head; implant stiffness has been proposed as an important factor to achieve adequate fracture fixation [32]. In contrast, in patients with reduced bone mass, a large mismatch between the stiffness of the implant and the osteoporotic bone may lead to ''stress riser'' followed by screw cut out or fracture at the end of the plate [19,33,34].…”

Risk Assessment of Retrograde Intramedullary Nailing for Proximal Humeral Fracture

“…However, locking plate fixation requires a large skin incision, being not low-invasive. Moreover, varus deformation, damage of the axillary nerve, and loss of blood supply to the humeral head are of concern [6,7].…”