title: Mechanical evaluation of adjunctive fixation for prevention of periprosthetic femur fracture with the Zurich cementless total hip prosthesis.
abstract: OBJECTIVE
  To evaluate whether cerclage wire or a lateral plate increases the peak-torque load to failure, compared to femora without adjunctive fixation, in femora implanted with Zurich Cementless stems.
  
  
  METHODS
  In vitro biomechanical study.
  
  
  METHODS
  Paired femora from adult dogs (n = 24) weighing 28-35 kg.
  
  
  METHODS
  Pairs of femora were implanted with a stem and randomly assigned to 2 treatment groups: cerclage or plate. Within each pair, either 3 loop cerclage wires or a laterally applied 12-hole Advanced Locking Plate System 10-mm plate (ALPS 10) were implanted in a femur, whereas the contralateral femur acted as control with no adjunctive fixation. After application of a static axial load each specimen was loaded to failure in torsion. Peak torque load at failure was compared between femora with each adjunctive fixation and the control using a paired t-test; P < .05 was considered significant.
  
  
  RESULTS
  In both treatment groups, femora with adjunctive fixation failed at higher loads compared to the femora without fixation; however, significant difference in peak torque at failure between treated femora and control was found only in the plated group (P < .05). Femora implanted with plates and with cerclage were 13.9% and 7.2% stronger in torsion than the femora without fixation, respectively.
  
  
  CONCLUSIONS
  Adjunctive fixation with a laterally applied ALPS 10 may aid in the prevention of peri-prosthetic fractures associated with Zurich Cementless medium stems.
authors.affiliation: Department of Small Animal Clinical Sciences, Comparative Orthopaedics and Biomechanics Laboratory, University of Florida, College of Veterinary Medicine, Gainesville, Florida, USA.
authors.forename: Antonio
authors.initials: A
authors.lastname: Pozzi
authors.forename: Jeffrey N
authors.initials: JN
authors.lastname: Peck
authors.forename: Peini
authors.initials: P
authors.lastname: Chao
authors.forename: Christina J
authors.initials: CJ
authors.lastname: Choate
authors.forename: Dan
authors.initials: D
authors.lastname: Barousse
authors.forename: Bryan
authors.initials: B
authors.lastname: Conrad
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001860:Bone Plates; D001864:Bone Wires; D002102:Cadaver; D004285:Dogs; D005260:Female; D005269:Femur; D050723:Fractures, Bone / Q000517:prevention & control; D006622:Hip Prosthesis / Q000662:veterinary*; D008422:Materials Testing; D011474:Prosthesis Design