title: A comparison of compressive force generation by plating and intramedullary nailing techniques in a transverse diaphyseal humerus fracture model.
abstract: BACKGROUND
  The null hypothesis to be tested in this study is that the compression forces generated with a novel compressible intramedullary nail are not different from compression plating techniques.
  
  
  METHODS
  A custom sensor was used to measure the compressive force at a transverse midshaft humeral sawbone osteotomy (OTA 12-A3.2) in four groups. The groups included: standard compression plating using a limited contact dynamic compression plate (LCDC) with eccentric screw placement (ED-LCDC), compression plating using an LCDC plate with an articulated tensioner and eccentric compression screw (AT-LCDC), locked humeral nail compressed using the manufacturer's long stainless steel screwdriver (T2-IMN), and locked humeral nail compressed using a short stainless steel AO screwdriver (SF-IMN). From continuous measurements recorded during osteotomy compression, the maximum force (CMax) and force at 60 seconds after the peak measurement (CMax +60) were analyzed.
  
  
  RESULTS
  The mean CMax was 2043 N for SF-IMN, 1109 N for AT-LCDC, 799 N for T2-IMN, and 365 N for ED-LCDC. Mean CMax +60 was 1648 N for SF-IMN, 944 N for AT-LCDC, 650 N for T2-IMN, and 319 N for ED-LCDC. The difference in both CMax and CMax +60 was statistically significant between all groups (p < 0.002).
  
  
  CONCLUSIONS
  A new humeral nail can generate higher compression than plating using eccentric drill holes or the articulated tensioner when used with a short stainless steel screwdriver shaft. Clinical studies are needed to analyze whether this compression could improve the union rate of humeral fractures and nonunions beyond those of standard nails.
authors.affiliation: Department of Orthopaedics, Rush University Medical Center, Chicago, Illinois, USA. orifer1@aol.com
authors.forename: Walter V
authors.initials: WV
authors.lastname: Virkus
authors.forename: Steven H
authors.initials: SH
authors.lastname: Goldberg
authors.forename: Eric P
authors.initials: EP
authors.lastname: Lorenz
mesh_terms: D001858:Bone Nails; D001860:Bone Plates; D002102:Cadaver; D019245:Compressive Strength; D018483:Diaphyses / Q000293:injuries; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation*; D006801:Humans; D006810:Humeral Fractures / Q000601:surgery*; D008422:Materials Testing; D008954:Models, Biological; D013314:Stress, Mechanical