title: Effectiveness of the surgical torque limiter: a model comparing drill- and hand-based screw insertion into locking plates.
abstract: BACKGROUND
  The objective of this study is to analyse the effectiveness of the surgical torque limiter during operative use. The study also investigates the potential differences in torque between hand and drill-based screw insertion into locking plates using a standardised torque limiter.
  
  
  METHODS
  Torque for both hand and power screw insertion was measured through a load cell, registering 6.66 points per second. This was performed in a controlled environment using synthetic bone, a locking plate and locking screws to simulate plate fixation. Screws were inserted by hand and by drill with torque values measured.
  
  
  RESULTS
  The surgical torque limiter (1.5 Nm) was effective as the highest recorded reading in the study was 1.409 Nm. Comparatively, there is a statistically significant difference between screw insertion methods. Torque produced for manually driven screw insertion into locking plates was 1.289 Nm (95 % CI 1.269-1.308) with drill-powered screw insertion at 0.740 Nm (95 % CI 0.723-0.757).
  
  
  CONCLUSIONS
  The surgical torque limiter proved to be effective as per product specifications. Screws inserted under power produce significantly less torque when compared to manual insertion by hand. This is likely related to the mechanism of the torque limiter when being used at higher speeds for which it was designed. We conclude that screws may be inserted using power to the plate with the addition of a torque limiter. It is recommended that all screws inserted by drill be hand tightened to achieve adequate torque values.
authors.affiliation: Orthopaedic Department, Gold Coast University Hospital, 1 Hospital Blvd, Southport, QLD, 4215, Australia.
authors.forename: Christopher
authors.initials: C
authors.lastname: Ioannou
authors.affiliation: Orthopaedic Department, Gold Coast University Hospital, 1 Hospital Blvd, Southport, QLD, 4215, Australia. matthew-knight@live.com.au.
authors.forename: Matthew
authors.identifier: http://orcid.org/0000-0002-9789-7373
authors.initials: M
authors.lastname: Knight
authors.affiliation: Orthopaedic Department, Gold Coast University Hospital, 1 Hospital Blvd, Southport, QLD, 4215, Australia.
authors.forename: Luca
authors.initials: L
authors.lastname: Daniele
authors.affiliation: Mechanical Engineering, Griffith University, Gold Coast, Queensland, Australia.
authors.forename: Lee
authors.initials: L
authors.lastname: Flueckiger
authors.affiliation: Orthopaedic Department, Gold Coast University Hospital, 1 Hospital Blvd, Southport, QLD, 4215, Australia.
authors.forename: Ezekiel S L
authors.initials: ES
authors.lastname: Tan
mesh_terms: D001860:Bone Plates; D001863:Bone Screws; D004867:Equipment Design; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods; D006225:Hand; D006801:Humans; D008954:Models, Biological; D013314:Stress, Mechanical; D019415:Torque
keywords: Drill; Hand; Limiter; Locking; Plate; Screw; Torque