Biomechanical comparison of mono- and bicortical screws in an experimentally induced gap fracture

D. Demner; T. C. Garcia; M. G. Serdy; K. Hayashi; B.-A. Nir; S. M. Stover

doi:10.3415/VCOT-14-03-0040

Veterinary and Comparative Orthopaedics and Traumatology, Inhaltsverzeichnis

Vet Comp Orthop Traumatol 2014; 27(06): 422-429
DOI: 10.3415/VCOT-14-03-0040

Original Research

Schattauer GmbH

Biomechanical comparison of mono- and bicortical screws in an experimentally induced gap fracture

Autor*innen

D. Demner

¹Pet Emergency & Specialty Center, Surgical Department, La Mesa, California, USA
T. C. Garcia

²UC Davis, Vet Med: APC, Davis, California, USA
M. G. Serdy

¹Pet Emergency & Specialty Center, Surgical Department, La Mesa, California, USA
K. Hayashi

³Cornell University, Clinical Sciences, College of Veterinary Medicine, Ithaca, NY, USA
B.-A. Nir

¹Pet Emergency & Specialty Center, Surgical Department, La Mesa, California, USA
S. M. Stover

⁴UC Davis, Surgical and Radiological Sciences, Davis, California, USA

Abstract

Summary

Objectives: To compare the bending and torsional mechanical properties of mono- and bicortical locking screws in a canine cadaveric tibial gap ostectomy bridged by a locking compression plate (LCP).

Methods: A 10-hole 3.5 mm LCP was applied medially to the tibia with a gap ostectomy using locking screws in the two proximal and distal plate holes. One tibia of each pair was randomly assigned monocortical screws and the other bicortical screws. Constructs were tested non-destructively in mediolateral and caudocranial four-point bending and torsion, and then to failure in four-point bending. Stiffness, yield and failure variables were compared between screw lengths and load conditions using analysis of variance.

Results: Caudocranial and mediolateral fourpoint bending stiffnesses were not different between screw constructs. Torsional stiffness was greater and neutral zone smaller for bicortical constructs. Constructs were stiffer and stronger in caudocranial bending than in mediolateral bending. In caudocranial bending, bicortical constructs failed by bone fracture and monocortical constructs by screw loosening.

Conclusion: Bicortical constructs were stiffer than monocortical constructs in torsion but not bending. Bicortical screw constructs failed by bone fracture under the applied loads whereas monocortical screw constructs failed at the bone-screw interface.

Clinical relevance: Bicortical screw placement may be a safer clinical alternative than monocortical screw placement for minimally invasive percutaneous osteosynthesis LCPplated canine tibiae with comminuted diaphyseal fractures.

Keywords

Monocortical - bicortical - biomechanical - locking compression plate - tibia

Volltext

Referenzen

References
1 Cross A. R. Fracture Biology and Biomechanics. In: Tobias KM, Johnston SA. editors. Veterinary Surgery: Small Animal. Vol. 1. First edition. St Louis, Missouri: Elsevier, Saunders; 2012: 565-571.
2 Koch D. Implants: description and application. Screws and plates. In: Johnson AL, Houlton JEF, Vannini R. editors. AO Principles of Fracture Management in the Dog and Cat Stuttgart: Thieme; 2005: 26-51.
3 Wagner M. General principles for the clinical use of the LCP. Injury 34 Suppl 2 2003; B31-B42.
4 Guiot LG, Dejardin LM. Prospective evaluation of minimally invasive plate osteosynthesis in 36 non articular tibial fractures in dogs and cats. Vet Surg 2011; 40: 171-182.
5 Dudley M, Johnson AL, Olmstead M. et al. Open reduction and bone plate stabilization, compared with closed reduction and external fixation, for treatment of comminuted tibial fractures: 47 cases (1980-1995) in dogs. J Am Vet Med Assoc 1997; 211: 1008-1012.
6 Haaland P, Sjostrom L, Devor M. et al. Appendicular fracture repair in dogs using the locking compression plate system: 47 cases. Vet Comp Orthop Traumatol 2009; 22: 309-315.
7 Gautier E, Sommer C. Guidelines for the clinical application of the LCP. Injury 2003; 34 (Suppl. 02) B63-B76.
8 Niemeyer P, Sudkamp NP. Principles and clinical application of the locking compression plate (LCP). Acta Chir Orthop Traumatol Cech 2006; 73: 221-228.
9 Aguila A, Manos J, Orlansky A. et al. In vitro biomechanical comparison of limited contact dynamic compression plate and locking compression plate. Vet Comp Orthop Traumatol 2005; 18: 220-206.
10 Goh CS, Santoni BG, Puttlitz CM. et al. Comparison of the mechanical behaviors of semi contoured, locking plate-rod fixation and anatomically contoured, conventional plate-rod fixation applied to experimentally induced gap in canine femora. Am J Vet Res 2009; 70: 23-29.
11 Matushek KJ, Sumner-Smith G, Schatzker J. et al. A strain-gauge study of the effect of external fixation on the canine tibia. Arch Orthop Trauma Surg 1989; 108: 159-165.
12 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.
13 Kubiak EN, Fulkerson E, Strauss E. et al. The evolution of locking plates. J Bone Joint Surg Am 2006; 88 (Suppl. 04) 189-200.
14 Blake CA, Boudrieau RJ, Torrance BS. et al. Single cycle to failure in bending of three standard and five locking plates and plate constructs. Vet Comp Orthop Traumatol 2011; 24: 408-417.
15 Miller EI, Acquaviva AE, Eisenmann DJ. et al. Perpendicular pull-out force of locking versus nonlocking plates in thin cortical bone using a canine mandibular ramus model. Vet Surg 2011; 40: 870-874.
16 Smith WR, Ziran BH, Anglen JO. et al. Locking plates: tips and tricks. J Bone Joint Surg Am 2007; 89: 2298-2307.
17 DeTora M, Kraus K. Mechanical testing of 3.5mm locking and nonlocking bone plates. Vet Comp Orthop Traumatol 2008; 21: 318-322.
18 Filipowicz D, Lanz O, McLaughlin R. et al. A biomechanical comparison of 3.5 locking compression plate fixation to 3.5 limited contact dynamic compression plate fixation in a canine cadaveric distal humeral metaphyseal gap model. Vet Comp Orthop Traumatol 2009; 22: 1-8.
19 Acquaviva AE, Miller EI, Eisenmann DJ. et al. Biomechanical testing of locking and nonlocking plates in the canine scapula. J Am Animal Hosp Assoc 2012; 48: 372-378.