title: Internal fixation of the distal humerus: a comprehensive biomechanical study evaluating current fixation techniques.
abstract: OBJECTIVE
  The purpose of this study was to evaluate current fixation techniques in the operative fixation of distal humerus fractures, both with conventional and locked plating in both parallel and orthogonal orientation.
  
  
  METHODS
  Twenty-eight upper extremities from 14 cadavers were prepared to create 4 implant testing constructs: Synthes locking plates (IMP1) (medial and posterolateral with lateral flange), Acumed parallel locking plates (IMP2), Smith & Nephew orthogonal locking plates (IMP3), and Synthes orthogonal 3.5-reconstruction plating (IMP4) (1 posterolateral and 1 medial). A 5-mm supracondylar osteotomy was made to simulate the fracture. Stiffness in axial and sagittal plane loading, fatigue properties (over 5000 cycles), and ultimate strength were determined for each construct by biomechanical testing.
  
  
  RESULTS
  The parallel locking plates (IMP2) exhibited the highest stiffness in axial load and the highest ultimate strength (P < 0.05). No significant differences in sagittal plane stiffness and in the fatigue properties were seen across the locking plate groups, regardless of orientation. Locked plating constructs performed significantly better in all categories when compared with conventional nonlocked plating. Plastic deformation and implant loosening were the main modes of failure after ultimate strength test.
  
  
  CONCLUSIONS
  Parallel locking plate configuration showed significantly higher stiffness to axial load and ultimate failure strength when compared with orthogonal locked and nonlocked plating. Locked plating configurations performed significantly better than nonlocked plating configurations, regardless of orientation. Although parallel orientation seems biomechanically superior, translation to the clinical setting may prove difficult when taking surrounding soft tissue and exposure into consideration.
authors.affiliation: *Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, Rutgers New Jersey Medical School, Newark, NJ; †Division of Orthopaedic Trauma, Department of Orthopaedic Surgery, NYU Hospital for Joint Diseases, New York, NY; and ‡Mount Sinai School of Medicine, New York, NY.
authors.forename: Paolo
authors.initials: P
authors.lastname: Caravaggi
authors.forename: Joseph L
authors.initials: JL
authors.lastname: Laratta
authors.forename: Richard S
authors.initials: RS
authors.lastname: Yoon
authors.forename: Justin
authors.initials: J
authors.lastname: De Biasio
authors.forename: Michael
authors.initials: M
authors.lastname: Ingargiola
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Frank
authors.forename: John T
authors.initials: JT
authors.lastname: Capo
authors.forename: Frank A
authors.initials: FA
authors.lastname: Liporace
mesh_terms: D001696:Biomechanical Phenomena; D001860:Bone Plates; D002102:Cadaver; D005593:Fracture Fixation, Internal / Q000379:methods*; D006801:Humans; D006810:Humeral Fractures / Q000503:physiopathology / Q000601:surgery*; D006811:Humerus / Q000601:surgery