title: Increased pin diameter improves torsional stability in supracondylar humerus fractures: an experimental study.
abstract: BACKGROUND
  Pediatric supracondylar humerus fractures are the most common elbow fractures seen in children, and account for 16 % of all pediatric fractures. Closed reduction and percutaneous pin fixation is the current treatment technique of choice for displaced supracondylar fractures of the distal humerus in children. The purpose of this study was to determine whether pin diameter affects the torsional strength of supracondylar humerus fractures treated by closed reduction and pin fixation.
  
  
  METHODS
  Pediatric sawbone humeri simulating a Gartland type III fracture were utilized. Four different pin configurations were compared. Specimens were subjected to a torsional load producing internal rotation of the distal fragment. The stability provided by 1.25- and 1.6-mm pins was compared.
  
  
  RESULTS
  The amount of torque required to produce 15° and 25° of rotation was greater using larger diameter pins in all models tested. The two lateral and one medial large pin (1.6 mm) configuration required the highest amount of torque to produce both 15° and 25° of rotation.
  
  
  CONCLUSIONS
  In a synthetic pediatric humerus model of supracondylar humerus fractures, larger diameter pins (1.6 mm) provided increased stability compared with small diameter pins (1.25 mm). Fixation using larger diameter pins created a stronger construct and improved the strength of fixation.
authors.affiliation: Pennsylvania State College of Medicine, 30 Hope Drive, Hershey, PA, 17033, USA.
authors.forename: Anupam
authors.initials: A
authors.lastname: Pradhan
authors.affiliation: Pennsylvania State College of Medicine, 30 Hope Drive, Hershey, PA, 17033, USA.
authors.forename: William
authors.initials: W
authors.lastname: Hennrikus
authors.affiliation: Pennsylvania State College of Medicine, 30 Hope Drive, Hershey, PA, 17033, USA. gpace@hmc.psu.edu.
authors.forename: Gregory
authors.initials: G
authors.lastname: Pace
authors.affiliation: Pennsylvania State College of Medicine, 30 Hope Drive, Hershey, PA, 17033, USA.
authors.forename: April
authors.initials: A
authors.lastname: Armstrong
authors.affiliation: Pennsylvania State College of Medicine, 30 Hope Drive, Hershey, PA, 17033, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Lewis
keywords: Elbow fracture; Humerus; Pediatric; Pin diameter; Supracondylar