title: Elastically suspending the screw holes of a locked osteosynthesis plate can dampen impact loads.
abstract: Impact damping by elastic fixation is a principal engineering strategy to increase the durability of load-bearing structures exposed to prolonged dynamic loading. This biomechanical study evaluated axial impact damping provided by a novel dynamic locking plate. In this design, locking screw holes are elastically suspended within a silicone envelope inside the locking plate. Axial impact damping was assessed for 3 distinct fixation constructs applied to bridge a 10-mm fracture gap of a femoral diaphysis surrogate: a standard locking plate, a dynamic locking plate, and an Ilizarov ring fixator. First, the 3 fixation constructs were characterized by determining their axial stiffness. Subsequently, constructs were subjected to a range of axial impact loads to quantify damping of force transmission. Compared with standard locked plating constructs, dynamic plating constructs were 58% less stiff (P < .01) and Ilizarov constructs were 88% less stiff (P < .01). Impact damping correlated inversely with construct stiffness. Compared with standard plating, dynamic plating constructs and Ilizarov constructs dampened the transmission of impact loads by up to 48% (P < .01) and 74% (P < .01), respectively. In conclusion, lower construct stiffness correlated with superior damping of axial impact loads. Dynamic locking plates provide significantly greater impact damping compared with standard locking plates.
authors: Biomechanics Laboratory, Legacy Research Institute, Portland, OR.
authors: Felix
authors: F
authors: Capanni
authors: Kirk
authors: K
authors: Hansen
authors: Daniel C
authors: DC
authors: Fitzpatrick
authors: Steven M
authors: SM
authors: Madey
authors: Michael
authors: M
authors: Bottlang
mesh_terms: D000054:Acceleration; D001860:Bone Plates; D001863:Bone Screws; D019245:Compressive Strength; D055119:Elastic Modulus; D019544:Equipment Failure Analysis; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D011474:Prosthesis Design; D013314:Stress, Mechanical; D014783:Viscosity