title: In vitro biomechanical comparison of dynamic compression plates with a rough contact surface and a polished contact surface for fixation of osteotomized equine third metacarpal bones.
abstract: OBJECTIVE
  To compare the number of cycles to failure of 4.5 mm broad dynamic compression plates (DCP), 4.5 mm broad limited-contact dynamic compression plates (4.5-LC-DCP), and 5.5 mm broad limited-contact dynamic compression plates (5.5-LC-DCP) having a rough (denoted by a prefix R-) versus a standard smooth contact surface for the fixation of osteotomized equine 3rd metacarpal (MC3) bones.
  
  
  METHODS
  Experimental.
  
  
  METHODS
  Fifteen pairs of adult equine cadaveric MC3 bones.
  
  
  METHODS
  Fifteen pairs of equine MC3 were divided into 3 test groups (5 pairs each) for comparison of (1) R-DCP fixation with DCP fixation, (2) R-4.5-LC-DCP fixation with 4.5-LC-DCP fixation, and (3) R-5.5-LC-DCP fixation with 5.5-LC-DCP fixation to repair osteotomized equine MC3 bones under palmarodorsal 4-point bending cyclic fatigue testing. For each group an 8-hole plate with rough contact surface was applied to the dorsal surface of one randomly selected bone from each pair and a corresponding 8-hole plate with smooth contact surface was applied dorsally to the contralateral bone from each pair. All plates and screws were applied using standard ASIF techniques. All MC3 bones had mid-diaphyseal osteotomies. Mean number of cycles to failure for each method were compared using a paired t-test within each group. Significance was set at P < .05.
  
  
  RESULTS
  Mean cycles to failure ± standard deviation was significantly greater for the R-DCP fixation (230,025 ± 23,129) compared with the DCP fixation (103,451 ± 14,556), for the R-4.5-LC-DCP fixation (99,237 ± 14,390) compared with the 4.5-LC-DCP fixation (46,464 ± 6325) and for the R-5.5-LC-DCP fixation (65,113 ± 7796) compared with the 5.5-LC-DCP fixation (34,224 ± 3835).
  
  
  CONCLUSIONS
  For the fixation of osteotomized MC3 bones, the constructs with plates having rough contact surface were superior to the corresponding constructs with plates having standard smooth contact surfaces in resisting cyclic fatigue under palmarodorsal 4-point bending.
authors.affiliation: Equine Health Studies Program, Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA. gsod@vetmed.lsu.edu
authors.forename: Gary A
authors.initials: GA
authors.lastname: Sod
authors.forename: Laura M
authors.initials: LM
authors.lastname: Riggs
authors.forename: Colin F
authors.initials: CF
authors.lastname: Mitchell
authors.forename: George S
authors.initials: GS
authors.lastname: Martin
authors.forename: Marjorie S
authors.initials: MS
authors.lastname: Gill
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001860:Bone Plates / Q000662:veterinary*; D005593:Fracture Fixation, Internal / Q000295:instrumentation / Q000379:methods / Q000662:veterinary*; D006736:Horses / Q000601:surgery*; D066298:In Vitro Techniques; D050279:Metacarpal Bones / Q000293:injuries* / Q000601:surgery; D010027:Osteotomy / Q000662:veterinary*; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011897:Random Allocation