title: A triangular support screw improves stability for lateral locking plates in proximal tibial fractures with metaphyseal comminution: a biomechanical analysis.
abstract: OBJECTIVE
  This study evaluates a proximally angulated cortical screw forming a triangular construct in lateral locking plates of comminuted intraarticular tibial plateau fractures.
  
  
  METHODS
  Sixteen composite tibiae were used for the fracture model and a complete articular fracture of the proximal tibia (AO 41.C2) was performed. A compression force was applied to the medial tibial plateau with an alternating, stepwise loading: 250 N-10 N-300 N-10 N-350 N-10 N-400 N. The relative motion between the different fragments of each sample was measured using a contactless, 3-dimensional digital image correlation system.
  
  
  RESULTS
  Between the medial and lateral condyle, elastic as well as plastic shear was significantly lower using the triangular support screw (p < 0.05). In the metaphyseal region, elastic deformation remained identical, independent of the screw positioning. However, plastic deformation (varus collapse) was significantly reduced by 30-40% using a triangular support screw at higher compression forces (>300 N; p < 0.05).
  
  
  CONCLUSIONS
  Based on the results of this study, the use of a triangular support screw in metaphyseal comminuted tibial plateau fractures might enhance fracture stability. However, further studies are necessary to prove these biomechanical results in composite bone.
authors.affiliation: Department of Orthopaedic Surgery, Kantonsspital St. Gallen, 9007 St. Gallen, Switzerland. patrick.baumann@kssg.ch
authors.forename: Patrick
authors.initials: P
authors.lastname: Baumann
authors.forename: Lukas
authors.initials: L
authors.lastname: Ebneter
authors.forename: Karlmeinrad
authors.initials: K
authors.lastname: Giesinger
authors.forename: Markus Stefan
authors.initials: MS
authors.lastname: Kuster
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D004548:Elasticity; D005593:Fracture Fixation, Internal / Q000379:methods*; D018460:Fractures, Comminuted / Q000601:surgery*; D006801:Humans; D008953:Models, Anatomic; D010027:Osteotomy; D011474:Prosthesis Design; D033081:Shear Strength; D013978:Tibial Fractures / Q000601:surgery*