title: The Metacarpal Locked Intramedullary Nail: Comparative Biomechanical Evaluation of New Implant Design for Metacarpal Fractures.
abstract: BACKGROUND
  The optimal fixation of metacarpal fracture should provide sufficient stability to permit early functionfor all types of fracture. However; it must preserve surrounding soft tissue during application and not require secondary removal due to its prominence. The prototype of metacarpal locked intramedullary nail (MCLN) was designed by our institute aiming to achieve those allfeatures.
  
  
  OBJECTIVE
  To biomechanically test our newly designed, locked metacarpal nail and compare with common current available fixation methods.
  
  
  METHODS
  Thirty chicken humeri were devided into 3 groups (n = 1 per group) according tofixation techniques: MCLN, 1.5 mm miniplate (Synthes), and Kirschner wire. After complete fixation, all specimens were osteotomized at mid-shaft creating transverse fractures. Five specimens from each group were tested by load of failure under axial compression, and another five under bending force.
  
  
  RESULTS
  In axial compression model, the loads tofailure in MCLN group was greatest (460 ± 17 N), which was significant higher than the Kirschner wire group. The MCLN group also showed the highest load to failure in bending test (341 ± 10 N). This value reaches statistical significance when compared with plate and Kirschner wire groups.
  
  
  CONCLUSIONS
  The MCLN construct provided higher stability than miniplate and Kirschner wire fixation both in axial and bending mode. Together with the minimally invasive and soft tissue-friendly design concept, this study suggests that MCLN is promising fixation option for metacarpal fracture.
authors.forename: Chinnakart
authors.initials: C
authors.lastname: Boonyasirikool
authors.forename: Sakkarin
authors.initials: S
authors.lastname: Tanakeatsakul
authors.forename: Sunyarn
authors.initials: S
authors.lastname: Niempoog
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001696:Biomechanical Phenomena; D001858:Bone Nails / Q000706:statistics & numerical data*; D002645:Chickens; D004867:Equipment Design; D004868:Equipment Failure; D019544:Equipment Failure Analysis / Q000706:statistics & numerical data; D005594:Fracture Fixation, Intramedullary / Q000379:methods / Q000706:statistics & numerical data*; D050723:Fractures, Bone; D050279:Metacarpal Bones