The effects of screw placement on plate strain  in 3.5 mm dynamic compression plates and  limited-contact dynamic compression plates

M. Maxwell; C. L. Horstman; R. L. Crawford; T. Vaughn; S. Elder; R. McLaughlin

doi:10.3415/VCOT-08-02-0023

Veterinary and Comparative Orthopaedics and Traumatology, Table of Contents

Vet Comp Orthop Traumatol 2009; 22(02): 125-131
DOI: 10.3415/VCOT-08-02-0023

Original Research

Schattauer GmbH

The effects of screw placement on plate strain in 3.5 mm dynamic compression plates and limited-contact dynamic compression plates

Authors

M. Maxwell

¹College of Veterinary Medicine; Mississippi State University, Mississippi State, Mississippi, USA
C. L. Horstman

²Las Vegas Veterinary Referral Center, Las Vegas, Nevada, USA
R. L. Crawford

³College of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, Mississippi, USA
T. Vaughn

³College of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, Mississippi, USA
S. Elder

³College of Agricultural and Biological Engineering, Mississippi State University, Mississippi State, Mississippi, USA
R. McLaughlin

Abstract

Summary

The objective of this study was to evaluate the effect of screw omission on plate strain during axial load to failure and cycling using a Delrin rod gap model. In addition, the differences between the 3.5 mm limited-contact dynamic compression plate (LC-DCP) and the 3.5 mm dynamic compression plate (DCP) were evaluated. Six, 12-hole LC-DCP and DCP plates were applied to Delrin rods with a 1 cm gap located within the central portion of the plate. Six screw configurations were tested with the following variations: three proximal and three distal (six open), four proximal and three distal (five open), four proximal and four distal (four open), five proximal and four distal (three open), five proximal and five distal (two open), six proximal and five distal (one open). Three strain gauges were mounted on each plate within the gap (gauge three) and extended proximally. Additionally, three constructs (six, three, and one open hole) were tested to failure in cyclic loading. The strain measured within the gap (gauge three) was significantly greater than the strain at other gauges for each screw configuration. Strain within the gap did not significantly change with any screw configuration, but did significantly increase at other locations as screws were omitted. Overall, the DCP withstood significantly more cycles than the LC-DCP. Differences were noted within the DCP group with the 6/5 screw configuration lasting for significantly more cycles than the 5/4 and 3/3 constructs. Although overall strain at the gap did not significantly increase with screw omission, the clinical significance remains to be determined.

Keywords

Strain - screw omission - limited-contact dynamic compression plate - dynamic compression plate

Full Text

References

References
1 Aguila 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.
2 Bernarde A, Diop A, Maurel N. et al. An in vitro biomechanical study of bone plate and interlocking nail in a canine diaphyseal femoral fracture model. Vet Surg 2001; 30: 397-408.
3 Reems MR, Beale BS, Hulse DA. Use of a plate-rod construct and principles of biological osteo-synthesis for repair of diaphyseal fractures in dogs and cats: 47 cases (1994–2001). J Am Vet Med Assoc 2003; 223: 330-335.
4 Palmer RH. Biological osteosynthesis. Vet Clin North Am Small Anim Pract 1999; 29: 1171-1185. vii
5 Perren SM. Evolution of the internal fixation of long bone fractures. The scientific basis of biological internal fixation: choosing a new balance between stability and biology. J Bone Joint Surg Br 2002; 84: 1093-1110.
6 Gerber C, Mast JW, Ganz R. Biological internal fixation of fractures. Arch Orthop Trauma Surg 1990; 109: 295-303.
7 Johnson AL, Smith CW, Schaeffer DJ. Fragment reconstruction and bone plate fixation versus bridging plate fixation for treating highly comminuted femoral fractures in dogs: 35 cases (1987–1997). J Am Vet Med Assoc 1998; 213: 1157-1161.
8 Hulse D, Hyman W, Nori M. et al. Reduction in plate strain by addition of an intramedullary pin. Vet Surg 1997; 26: 451-459.
9 Hulse DF, Fawcett K, Gentry A. et al. Effect of intramedullary pin size on reducing plate strain. Vet Comp Orthop Traumatol 2000; 13: 185-190.
10 Neidlinger-Wilke C, Holbein O, Grood E. et al. Effects of cycling strain on proliferation, metabolic activity, and alignment of human osteoblasts and fibroblasts. Trans ORS 19: 101. 1884 (abstr)
11 Slatter D. Fracture biology and biomechanics. In: Hulse DH, B, editor. Textbook of small animal surgery. Philadelphia: Saunders; 2003: 1785-1792.
12 Goodship AE, Lanyon LE, McFie H. Functional adaptation of bone to increased stress. An experimental study. J Bone Joint Surg Am 1979; 61: 539-546.
13 Korvick DL, Monville JD, Pijanowski GJ. et al. The effects of screw removal on bone strain in an idealized plated bone model. Vet Surg 1988; 17: 111-116.
14 Field JR, Tornkvist H, Hearn TC. et al. The influence of screw omission on construction stiffness and bone surface strain in the application of bone plates to cadaveric bone. Injury 1999; 30: 591-598.
15 Ellis T, Bourgeault CA, Kyle RF. Screw position affects dynamic compression plate strain in an in vitro fracture model. J Orthop Trauma 2001; 15: 333-337.
16 Jain R, Podworny N, Hupel TM. et al. Influence of plate design on cortical bone perfusion and fracture healing in canine segmental tibial fractures. J Orthop Trauma 1999; 13: 178-186.
17 Egol KA, Kubiak EN, Fulkerson E. et al. Biomechanics of locked plates and screws. J Orthop Trauma 2004; 18: 488-493.
18 Ann Johnson JEFH. Rico Vannini. AO principle of fracture management in the dog and cat. Davos, Switzerland: Thieme; 2005: 38-39
19 Horstman CL, Beale BS, Conzemius MG. et al. Biological osteosynthesis versus traditional anatomic reconstruction of 20 long-bone fractures using an interlocking nail: 1994–2001. Vet Surg 2004; 33: 232-237.