Caleb C Hudson 1 , Daniel D Lewis , Alan R Cross , Nicholas J Dunbar , MaryBeth Horodyski , Scott A Banks , Antonio Pozzi Show Affiliations »
Abstract
OBJECTIVE: To evaluate the stiffness, displacement, ring deformation and bone model motion of 3 configuations of linear-circular hybrid fixator constructs loaded in axial compression, craniocaudal and mediolateral bending, and torsion. STUDY DESIGN: Biomechanical evaluation. SAMPLE POPULATION: Three hybrid construct configurations with 8 replicates/configuration. METHODS: Construct Ia used a single, 84 mm, incomplete ring and 2 tensioned olive wires to stabilize 1 bone segment and a primary hybrid rod with 3 fixation pins to stabilize the other bone segment. Constructs Ia(d) and Ib were similar to Ia with the addition of a secondary diagonal hybrid rod. Construct Ib had a fixation pin inserted orthogonally from the diagonal rod. Constructs were loaded for 10 cycles in each mode of loading using a materials testing machine. Ring deformation was assessed by obtaining serial ring measurements. Bone model motion at the fracture gap as a result of loading was also calculated. RESULTS: Axial compression: constructs Ia(d) and Ib were significantly stiffer than construct Ia. Craniocaudal bending: Construct Ib was significantly stiffer than construct Ia. Mediolateral bending: there were no significant differences between constructs. Torsion: Construct Ib was significantly stiffer than constructs Ia and Ia(d) . Permanent ring deformation did not occur. Bone model translational motion decreased in constructs Ia(d) and Ib compared to construct Ia. CONCLUSIONS: Addition of a secondary hybrid rod as well as biplanar fixation pin placement improved construct stiffness in several loading modes. © Copyright 2012 by The American College of Veterinary Surgeons.
OBJECTIVE: To evaluate the stiffness, displacement, ring deformation and bone model motion of 3 configuations of linear-circular hybrid fixator constructs loaded in axial compression, craniocaudal and mediolateral bending, and torsion. STUDY DESIGN: Biomechanical evaluation. SAMPLE POPULATION: Three hybrid construct configurations with 8 replicates/configuration. METHODS: Construct Ia used a single, 84 mm, incomplete ring and 2 tensioned olive wires to stabilize 1 bone segment and a primary hybrid rod with 3 fixation pins to stabilize the other bone segment. Constructs Ia(d) and Ib were similar to Ia with the addition of a secondary diagonal hybrid rod. Construct Ib had a fixation pin inserted orthogonally from the diagonal rod. Constructs were loaded for 10 cycles in each mode of loading using a materials testing machine. Ring deformation was assessed by obtaining serial ring measurements. Bone model motion at the fracture gap as a result of loading was also calculated. RESULTS: Axial compression: constructs Ia(d) and Ib were significantly stiffer than construct Ia. Craniocaudal bending: Construct Ib was significantly stiffer than construct Ia. Mediolateral bending: there were no significant differences between constructs. Torsion: Construct Ib was significantly stiffer than constructs Ia and Ia(d) . Permanent ring deformation did not occur. Bone model translational motion decreased in constructs Ia(d) and Ib compared to construct Ia. CONCLUSIONS: Addition of a secondary hybrid rod as well as biplanar fixation pin placement improved construct stiffness in several loading modes. © Copyright 2012 by The American College of Veterinary Surgeons.
Entities: Species
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Year: 2012
PMID： 22957475 DOI： 10.1111/j.1532-950X.2012.01035.x
Source DB: PubMed Journal: Vet Surg ISSN： 0161-3499 Impact factor: 1.495