Comparison of double locking plate constructs with single non-locking plate constructs in single cycle to failure in bending and torsion

Summary

Objective: To evaluate the biomechanical properties of single 3.5 mm broad dynamic compression plate (DCP) and double 3.5 mm String-of-Pearls (SOP) plate constructs in single-cycle bending and torsion. We hypothesized that the double SOP construct would outperform the broad DCP in both bending and torsional testing.

Methods: Broad DCP plates and double 3.5 mm SOP plates were secured to a previously validated bone model in an effort to simulate bridging osteosynthesis. Constructs were tested in both four-point bending and torsional testing.

Results: The double SOP constructs had significantly greater bending stiffness, bending strength, bending structural stiffness, and torsional stiffness when compared to the broad DCP constructs. The single broad DCP constructs had significantly higher yield torque and yield angles during torsional testing.

Clinical relevance: Although the in vitro mechanical performance of the double SOP construct was significantly greater than the single broad DCP constructs under bending loads, the actual differences were small. Various patient, fracture, and implant factors must be considered when choosing an appropriate implant for fracture fixation.

Keywords

String-of-Pearls - broad dynamic compression plate - implant failure - bending - torsion

• References

• 1 Perren SM. Evolution of the internal fixations of long bone fractures. The scientific basis of biological internal fixation: choosing a new balance between stability and biology. J Bone Joint Surgery 2002; 84 B 1093-1110.
• 2 Johnston SA, von Pfeil DJF, Déjardin L. et al. Internal Fracture Fixation. In Tobias KM, Johnston SA.. editors Veterinary Surgery: Small Animal. Vol 1. 1st ed. St Louis: Elsevier; 2012: 576-607.
• 3 Perren SM, Klaue K, Pohler O. et al. The limited contact dynamic compression plate (LC-DCP). Arch Orthop Trauma Surg 1990; 109: 304-310.
• 4 Borgeaud M, Cordey J, Leyvraz PF. et al. Mechanical analysis of the bone to plate interface of the LC-DCP and of the PC-FIX on human femora. Injury 2000; 31: S-C29-C36.
• 5 Rozbruch SR, Muller U, Gautier E. et al. The evolution of femoral shaft plating technique. Clin Orthop Rel Res 1998; 354: 195-208.
• 6 Schutz M, Sudkamp NP. Revolution in plate osteosynthesis: new internal fixator systems. J Orthop Sci 2003; 8: 252-258.
• 7 Miclau T, Martin RE. The evolution of modern plate osteosynthesis. Injury 1997; 28 (01) A3-A6.
• 8 Aquilla AZ, Manos JM, Orlansky AS. et al. In vitro biomechanical comparison of limited contact dynamic compression plate and locking compression plate. Vet Comp Orthop Traumatol 2005; 18: 220-226.
• 9 Ness MG. The effect of bending and twisting on the stiffness and strength of the 3.5 SOP implant. Vet Comp Orthop Traumatol 2009; 22: 132-136.
• 10 Blake CA, Boudrieau RJ, Torrance BS. et al. Single cycle to failure in bending of three standard and five locking plate and plate constructs. Vet Comp Orthop Traumatol 2011; 6: 408-418.
• 11 DeTora M, Kraus K. Mechanical testing of 3.5 mm locking and non-locking bone plates. Vet Comp Orthop Traumtol 2008; 21: 318-322.
• 12 Cabassu JB, Kowaleski MP, Shorinko JK. et al. Single cycle to failure in torsion of three standard and five locking plate constructs. Vet Comp Orthop Traumatol 2011; 6: 418-425.
• 13 Kraus KH, Ness MG. Standard Operating Procedures for SOP Fixation of Fractures [Product Instructions]. West Yorkshire, UK: Orthomed; October 2007
• 14 Acker ML, Torrance B, Kowaleski MP. et al. Structural properties of synthetic bone models compared to native canine bone. Proceedings of the 19th Annual Scientific meeting of the European College of Veterinary Surgeons. 2010. July 1-3 Helsinki, Finland: 150-151.
• 15 Johnson AL, Houlton JE, Vannini R. AO Principles of Fracture Management in the Dog and Cat. Davos, Switzerland: AO Publishing; 2005
• 16 American Society for Testing and Materials. Standard Specification and Test Method for Metallic Bone Plates, ASTM F382-99 (reapproved 2003). In: 2003 Annual Book of ASTM Standards. West Conshoohocken, PA: ASTM; 2003.
• 17 Tyler JM, Larinde W, Elder SH. A device for performing whole bone torsional testing in a single-axis linear motion testing machine. Vet Comp Orthop Traumatol 2008; 21: 478-480.
• 18 Malenfant RC, Sod GA. In vitro biomechanical comparison of 3.5 String-of-pearlsTM plate fixation to 3.5 locking compression plate fixation in a canine fracture gap model. Vet Surg 2014; 43: 465-470.
• 19 Gautier E, Perren SM, Cordey J. Strain distribution in plated and unplated sheep tibia an in vivo experiment. Injury 2000; 31 Suppl (Suppl. 03) C37-C44.
• 20 Bertram JEA, Lee DV, Case HN. et al. Comparison of the trotting gaits of Labrador Retrievers and Greyhounds. Am J Vet Res 2000; 61: 832-838.
• 21 Ahmad M, Nanda R, Bajwa AS. et al. Biomechanical testing of the locking compression plate: When does the distance between the bone and implant significantly reduce construct stability?. Injury 2007; 38: 358-364.
• 22 Rotne R, Bertollo N, Walsh W. et al. Influence of plate-bone contact on cyclically loaded conically coupled locking plate failure. Injury 2014; 45: 515-521.