Distal femur fractures of the elderly—Different treatment options in a biomechanical comparison

Implant Material and Design Alter Construct Stiffness in Distal Femur Locking Plate Fixation: A Pilot Study

“…Many of these fractures had uneventful but deficient healing as been reported and has also been associated with the mechanical performance of fracture fixation [3,9]. The mechanical performance of fracture fixation differs considerably among different implant fixation systems [11,19,20,24,25] but state-of-the-art systems have so far not been compared using consistent assessment methodology. To perform a direct comparison with multiple new-generation distal femur locking plates, we biomechanically evaluated four plating systems addressing two questions: will different distal femur locking plate systems and constructs lead to differing (1) axial and rotational stiffness and (2) fatigue under cyclic loading?…”

“…Not only does the choice of implants such as nails, conventional plates, or locking plates for the same fracture pattern alter construct stiffness [11,19,20], but also using locking plate fixation and different screw configurations such as using far cortical locking screws can alter the stiffness up to 81% [3]. Therefore, although using locking plate systems for distal femur fixation, the knowledge of basic differences in biomechanical performance configurations might help the surgeon in implant selection and/or altering his screw configuration.…”

“…2) and was adapted from a test setup reported by Wähnert et al [19] that allows cardanic joints. This configuration would simulate the axial and torsional loads experienced during ground-level walking [17,18].…”

“…As a result of the aging population, the incidence of fractures of the distal femur is increasing [19], especially in patients with osteoporosis. During the past decade, retrograde intramedullary devices [20] as well as new generations of distal femur locked plating systems [9] have facilitated the operative treatment of these fractures.…”

“…Henderson et al [10] suggested stainless steel locking plates are associated with a higher percentage of nonunions than titanium plates (57% versus 43%, respectively). Many investigators have explored comparisons of distal femur locked plating systems with intramedullary nail systems [19,20,25], angled blade plates [11,24,25], dynamic condylar screws [11], and locked plating constructs with different screw configurations in the condylar fragment of the fracture model [8,16]. However, reported stiffness values for the same implant vary up to more than one order of magnitude, perhaps as a result of differing configurations of the boneimplant constructs (BICs) or test equipment.…”