title: Intramedullary Nailing of Tibial Shaft Fractures: Size Matters.
abstract: OBJECTIVE
  To determine optimal ratio of intramedullary nail diameter to tibial canal diameter that leads to reliable and timely healing in tibial shaft fractures.
  
  
  METHODS
  Retrospective case series.
  
  
  METHODS
  Level I trauma center.
  
  
  METHODS
  One hundred thirty-three fractures in 132 patients with tibial shaft fractures that underwent intramedullary nailing as definitive fixation were identified between June 2004 and July 2012 at our level I trauma center. Of these, 78 had serial radiographs out to 12 months that could be analyzed for radiographic healing with an average age of 37 years old (range 16-86 years). There were 52 males and 26 females.
  
  
  METHODS
  All patients underwent intramedullary nailing of the tibia with documentation of both the diameter of the nail and radiographic canal width at the isthmus to determine the nail to canal ratio.
  
  
  METHODS
  Patients were followed with serial radiographs for at least 12 months to determine time to healing as a function of nail to canal ratio. The senior author assessed healing at 3, 6, 9, and 12 months using RUST criteria.
  
  
  RESULTS
  Patients with an intramedullary nail to canal diameter ratio of less than 0.8 or greater than 0.99 were 4.4 times more likely not to heal than patients with a ratio of between 0.8 and 0.99.
  
  
  CONCLUSIONS
  The ideal intramedullary nail to tibial canal diameter ratio to optimize tibial shaft fracture healing is between 0.8 and 0.99.
  
  
  METHODS
  Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: *Department of Orthopaedic Surgery, University of Pennsylvania Health System, Philadelphia, PA;†Department of Orthopaedic Surgery, Maimonides Medical Center, Brooklyn, NY; and‡Department of Orthopaedic Surgery, University of Texas-Houston, Houston, TX.
authors.forename: Derek J
authors.initials: DJ
authors.lastname: Donegan
authors.forename: Sheriff
authors.initials: S
authors.lastname: Akinleye
authors.forename: Ryan M
authors.initials: RM
authors.lastname: Taylor
authors.forename: Keith
authors.initials: K
authors.lastname: Baldwin
authors.forename: Samir
authors.initials: S
authors.lastname: Mehta
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001858:Bone Nails / Q000145:classification*; D015331:Cohort Studies; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D005594:Fracture Fixation, Intramedullary / Q000295:instrumentation* / Q000379:methods; D017102:Fracture Healing / Q000502:physiology*; D006801:Humans; D015601:Injury Severity Score; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D018570:Risk Assessment; D013978:Tibial Fractures / Q000175:diagnosis / Q000601:surgery*; D014193:Trauma Centers; D055815:Young Adult