title: Fixation of Metacarpal Shaft Fractures: Biomechanical Comparison of Intramedullary Nail Crossed K-Wires and Plate-Screw Constructs.
abstract: OBJECTIVE
  Metacarpal (MC) fractures are very common, accounting for 18% of all fractures distal to the elbow. Many MC fractures can be treated non-operatively; however, some are treated most effectively with surgical stabilization, for which there are multiple methods. It was postulated that plates would have a significantly higher (P < 0.05) load to failure than crossed K(XK)-wires and that intramedullary metacarpal nails (IMNs) and XK-wires would have equivalent load to failure.
  
  
  METHODS
  Mid-diaphyseal transverse fractures were created in 36 synthetic metacarpals and stabilized using nails, XK-wires or non-locking plates. Three-point bending was performed with continuous recording of load and displacement. Statistical analysis was performed using single factor ANOVA and Scheffe's test. Statistical significance was defined as P < 0.05.
  
  
  RESULTS
  Biomechanical testing revealed significant differences between groups in load-to-failure. Average load to failure was significantly greater in the plate (1669 ± 322 N) than the XK-wire (146 ± 56 N) or IMN (110 ± 43 N) groups. The loads to failure of the K-wires and nails were equivalent. Plates were 11 and 15 times stronger in three-point bending than the K-wires and nails, respectively. There was no statistically significant difference between strengths of the K-wires and nails.
  
  
  CONCLUSIONS
  Although plates are the most stable means of fixation of midshaft metacarpal fractures, if minimally-invasive techniques are indicated, intramedullary nails may provide equivalent stability as commonly-used XK-wires. Although some studies have shown favorable clinical outcomes with IMNs, additional clinical correlation of these biomechanical results to fracture healing and outcomes is needed.
authors: Department of Orthopaedics, Wexner Medical Center, Ohio State University, Columbus, Ohio, USA.
authors: Benjamin D
authors: BD
authors: Curtis
authors: Department of Orthopaedics, Wexner Medical Center, Ohio State University, Columbus, Ohio, USA.
authors: Olukemi
authors: O
authors: Fajolu
authors: Department of Orthopaedics, Wexner Medical Center, Ohio State University, Columbus, Ohio, USA.
authors: Michael E
authors: ME
authors: Ruff
authors: Department of Orthopaedics, Wexner Medical Center, Ohio State University, Columbus, Ohio, USA.
authors: Alan S
authors: AS
authors: Litsky
mesh_terms: D001696:Biomechanical Phenomena; D001858:Bone Nails; D001860:Bone Plates; D001863:Bone Screws; D001864:Bone Wires; D019544:Equipment Failure Analysis / Q000379:methods; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation / Q000379:methods; D050723:Fractures, Bone / Q000601:surgery*; D006801:Humans; D016268:Internal Fixators; D008422:Materials Testing / Q000379:methods; D050279:Metacarpal Bones / Q000293:injuries* / Q000601:surgery*; D011475:Prosthesis Failure
keywords: Biomechanical; Intramedullary nail; Metacarpal fracture; Stabilization