title: Biomechanical evaluation of proximally placed femoral less-invasive stabilization system plates.
abstract: Loss of fixation of the Synthes 13-hole femoral Less-Invasive Stabilization System (LISS) plate has been noted. The biomechanical stability of this plate may be affected by improper proximal placement. We conducted a study to determine if there is any difference in fixation failure, deformation, or stiffness based on proximal placement. Using synthetic composite bones, we created a comminuted supracondylar distal femur fracture, AO/OTA (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association) 33-A3. Three groups of 9 femurs each were created: 1 correctly positioned group and 2 incorrectly positioned groups, 1 with the proximal aspect of the plate 1 cm anterior and 1 with the proximal aspect of the plate 1 cm posterior. The constructs were tested in axial, torsional, and cyclical axial modes to assess plastic and total deformation and stiffness. Under axial loading, the posteriorly placed plate showed a 16.4% increase in stiffness. There was a significant increase of 12% in torsional stiffness in the anteriorly placed plate. Under cyclical axial loading, there was a significant increase of 14% in total deformation in the anteriorly placed plate. No fixation failure was observed. One-centimeter variation in proximal placement of a 13-hole LISS plate in a synthetic composite fracture model had little effect on the overall construct.
authors: Barry C
authors: BC
authors: Davis
authors: Department of Orthopaedics, West Virginia University, Morgantown, WV. dmcconda@hsc.wvu.edu.
authors: David B
authors: DB
authors: McConda
authors: David F
authors: DF
authors: Hubbard
authors: Vincent L
authors: VL
authors: Kish
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D005264:Femoral Fractures / Q000601:surgery*; D005269:Femur / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods*; D018460:Fractures, Comminuted / Q000601:surgery*; D006801:Humans; D008422:Materials Testing; D008953:Models, Anatomic