Biomechanical comparison of two locking plate constructs under cyclic torsional loading in a fracture gap model

A. Bilmont; S. Palierne; M. Verset; P. Swider; A. Autefage

doi:10.3415/VCOT-14-12-0181

Veterinary and Comparative Orthopaedics and Traumatology, Table of Contents

Vet Comp Orthop Traumatol 2015; 28(05): 323-330
DOI: 10.3415/VCOT-14-12-0181

Original Research

Schattauer GmbH

Biomechanical comparison of two locking plate constructs under cyclic torsional loading in a fracture gap model

Two screws versus three screws per fragment

A. Bilmont

¹Université de Toulouse, INP, Ecole Nationale Vétérinaire de Toulouse, Unité de Recherche Clinique, Laboratoire de Biomécanique, Toulouse, France

,

S. Palierne

¹Université de Toulouse, INP, Ecole Nationale Vétérinaire de Toulouse, Unité de Recherche Clinique, Laboratoire de Biomécanique, Toulouse, France

,

M. Verset

¹Université de Toulouse, INP, Ecole Nationale Vétérinaire de Toulouse, Unité de Recherche Clinique, Laboratoire de Biomécanique, Toulouse, France

,

P. Swider

²Université de Toulouse, Institut de Mécanique des Fluides de Toulouse (IMFT) UMR CNRS 5502, Toulouse, France

,

A. Autefage

¹Université de Toulouse, INP, Ecole Nationale Vétérinaire de Toulouse, Unité de Recherche Clinique, Laboratoire de Biomécanique, Toulouse, France

› Author Affiliations

Abstract

Summary

Objectives: The number of locking screws required per fragment during bridging osteo-synthesis in the dog has not been determined. The purpose of this study was to assess the survival of two constructs, with either two or three screws per fragment, under cyclic torsion.

Methods: Ten-hole 3.5 mm stainless steel locking compression plates (LCP) were fixed 1 mm away from bone surrogates with a fracture gap of 47 mm using two bicortical locking screws (10 constructs) or three bicortical locking screws (10 constructs) per fragment, placed at the extremities of each LCP. Constructs were tested in cyclic torsion (range: 0 to +0.218 rad) until failure.

Results: The 3-screws constructs (29.65 ± 1.89 N.m/rad) were stiffer than the 2-screws constructs (23.73 ± 0.87 N.m/rad), and therefore, were subjected to a greater torque during cycling (6.05 ± 1.33 N.m and 4.88 ± 1.14 N.m respectively). The 3-screws constructs sustained a significantly greater number of cycles (20,700 ± 5,735 cycles) than the 2-screws constructs (15,600 ± 5,272 cycles). In most constructs, failure was due to screw damage at the junction of the shaft and head. The remaining constructs failed because of screw head unlocking, sometimes due to incomplete seating of the screw head prior to testing.

Clinical significance: Omitting the third innermost locking screw during bridging osteosynthesis led to a reduction in fatigue life of 25% and construct stiffness by 20%. Fracture of the screws is believed to occur sequentially, starting with the innermost screw that initially shields the other screws.

Keywords

Cyclic testing - locking plate - screw - torsion

Full Text

References

References
1 Guiot LP, Dejardin LM. Prospective evaluation of minimally invasive plate osteosynthesis in 36 nonarticular tibial fractures in dogs and cats. Vet Surg 2011; 40: 171-182.
2 Hudson CC, Pozzi A, Lewis DD. Minimally invasive plate osteosynthesis: applications and techniques in dogs and cats. Vet Comp Orthop Traumatol 2009; 22: 175-182.
3 Gautier E, Sommer C. Guidelines for the clinical application of the LCP. Injury 2003; 34 (Suppl. 02) B63-76.
4 Sommer C, Gautier E, Muller M. et al. First clinical results of the locking compression plate (LCP). Injury 2003; 34 (Suppl. 02) B43-54.
5 Hertel R, Eijer H, Meisser A. et al. Biomechanical and biological considerations relating to the clinical use of the Point Contact-Fixator--evaluation of the device handling test in the treatment of diaphyseal fractures of the radius and/or ulna. Injury 2001; 32 (Suppl. 02) B10-14.
6 Sanders R, Haidukewych GJ, Milne T. et al. Minimal versus maximal plate fixation techniques of the ulna: the biomechanical effect of number of screws and plate length. J Orthop Trauma 2002; 16: 166-171.
7 Stoffel K, Dieter U, Stachowiak G. et al. Biomechanical testing of the LCP--how can stability in locked internal fixators be controlled?. Injury 2003; 34 (Suppl. 02) B11-19.
8 Wagner M. General principles for the clinical use of the LCP. Injury 2003; 34 (Suppl. 02) B31-42.
9 Field JR, Hearn TC, Woodside TD. The influence of screw torque in the application of bone plates. Vet Comp Orthop Traumatol 2001; 14: 78-83.
10 Garofolo S, Pozzi A. Effect of plating technique on periosteal vasculature of the radius in dogs: a cadaveric study. Vet Surg 2013; 42: 255-261.
11 Haaland PJ, 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.
12 Nicetto T, Petazzoni M, Urizzi A. et al. Experiences using the Fixin locking plate system for the stabilization of appendicular fractures in dogs: a clinical and radiographic retrospective assessment. Vet Comp Orthop Traumatol 2013; 26: 61-68.
13 Voss K, Kull M, Hassig M. et al. Repair of long-bone fractures in cats and small dogs with the Unilock mandible locking plate system. Vet Comp Orthop Traumatol 2009; 22: 398-405.
14 Ahmad M, Nanda R, Bajwa AS. et al. Biomechanical testing of the locking compression plate: when does the distance between bone and implant significantly reduce construct stability?. Injury 2007; 38: 358-364.
15 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; 24: 418-425.
16 Dejardin LM, Lansdowne JL, Sinnott MT. et al. In vitro mechanical evaluation of torsional loading in simulated canine tibiae for a novel hourglass-shaped interlocking nail with a self-tapping tapered locking design. Am J Vet Res 2006; 67: 678-685.
17 Acker BT, 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 European College of Veterinary Surgeons 2010. July 1-3 Helsinki: Finland; 150-151.
18 Gautier E, Perren SM, Cordey J. Strain distribution in plated and unplated sheep tibia an in vivo experiment. Injury 2000; 31 (Suppl. 03) C37-44.
19 Lansdowne JL, Sinnott MT, Dejardin LM. et al. In vitro mechanical comparison of screwed, bolted, and novel interlocking nail systems to buttress plate fixation in torsion and mediolateral bending. Vet Surg 2007; 36: 368-377.
20 Malenfant RC, Sod GA. In vitro biomechanical comparison of 3.5 string of pearl plate fixation to 3.5 locking compression plate fixation in a canine fracture gap model. Vet Surg 2014; 43: 465-470.
21 Chan CB, Spierenburg M, Ihle SL. et al. Use of pedometers to measure physical activity in dogs. J Am Vet Med Assoc 2005; 226: 2010-2015.
22 Bottlang M, Doornink J, Byrd GD. et al. A nonlocking end screw can decrease fracture risk caused by locked plating in the osteoporotic diaphysis. J Bone Joint Surg Am 2009; 91A: 620-627.
23 Doornink J, Fitzpatrick DC, Boldhaus S. et al. Effects of hybrid plating with locked and nonlocked screws on the strength of locked plating constructs in the osteoporotic diaphysis. J Trauma 2010; 69: 411-417.
24 Estes C, Rhee P, Shrader MW. et al. Biomechanical strength of the Peri-Loc proximal tibial plate: a comparison of all-locked versus hybrid locked/nonlocked screw configurations. J Orthop Trauma 2008; 22: 312-316.
25 Fitzpatrick DC, Doornink J, Madey SM. et al. Relative stability of conventional and locked plating fixation in a model of the osteoporotic femoral diaphysis. Clin Biomech (Bristol, Avon) 2009; 24: 203-209.
26 Zlowodzki M, Williamson S, Cole PA. et al. Biomechanical evaluation of the less invasive stabilization system, angled blade plate, and retrograde intramedullary nail for the internal fixation of distal femur fractures. J Orthop Trauma 2004; 18: 494-502.
27 Kanchanomai C, Phiphobmongkol V, Muanjan P. Fatigue failure of an orthopedic implant - A locking compression plate. Eng Fail Analysis 2008; 521-530.
28 Stoffel K, Lorenz KU, Kuster MS. Biomechanical considerations in plate osteosynthesis: the effect of plate-to-bone compression with and without angular screw stability. J Orthop Trauma 2007; 21: 362-368.
29 Hak DJ, Althausen P, Hazelwood SJ. Locked plate fixation of osteoporotic humeral shaft fractures: are two locking screws per segment enough?. J Orthop Trauma 2010; 24: 207-211.
30 Miller DL, Goswmi T. A review of locking compression plate biomechanics and their advantages as internal fixators in fracture healing. Clinical Biomechanics 2007; 22: 1049-1062.
31 Claes LE, Heigele CA. Magnitudes of local stress and strain along bony surfaces predict the course and type of fracture healing. J Biomech 1999; 32: 255-266.
32 Comiskey DP, MacDonald BJ, McCartney WT. et al. The role of interfragmentary strain on the rate of bone healing-A new interpretation and mathematical model. J Biomech 2010; 43: 2830-2834.
33 Schutz M, Muller M, Krettek C. et al. Minimally invasive fracture stabilization of distal femoral fractures with the LISS: a prospective multicenter study. Results of a clinical study with special emphasis on difficult cases. Injury 2001; 32 (Suppl. 03) SC48-54.
34 Charalambous CP, Siddique I, Valluripalli K. et al. Proximal humeral internal locking system (PHILOS) for the treatment of proximal humeral fractures. Arch Orthop Trauma Surg 2007; 127: 205-210.
35 Case JB, Dean C, Wilson DM. et al. Comparison of the mechanical behaviors of locked and nonlocked plate/screw fixation applied to experimentally induced rotational osteotomies in canine ilia. Vet Surg 2012; 41: 103-113.
36 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: 270-277.
37 ASTM F382-99: (2008). Standard Specification and Test Method for Metallic Bone Plates. West Conshohocken, PA (USA): ASTM International; 2008 Available from: www.astm.org
38 Celestre P, Roberston C, Mahar A. et al. Biomechanical evaluation of clavicle fracture plating techniques: does a locking plate provide improved stability?. J Orthop Trauma 2008; 22: 241-247.
39 Hamman D, Lindsey D, Dragoo J. Biomechanical analysis of bicortical versus unicortical locked plating of mid-clavicular fractures. Arch Orthop Trauma Surg 2011; 131: 773-778.
40 Partal G, Meyers KN, Sama N. et al. Superior versus anteroinferior plating of the clavicle revisited: A mechanical study. J Orthop Trauma 2010; 24: 420-425.
41 Sutherland GB, Creekmore T, Mukherjee DP. et al. Biomechanics of humerus fracture fixation by locking, cortical, and hybrid plating systems in a cadaver model. Orthopedics 2010; 33
42 Goh CSS, Santoni BG, Puttlitz CM. et al. Comparison of the mechanical behaviors of semicontoured, locking plate-rod fixation and anatomically contoured, conventional plate-rod fixation applied to experimentally induced gap fractures in canine femora. Am J Vet Res 2009; 70: 23-29.
43 Hammel SP, Pluhar GE, Novo RE. et al. Fatigue analysis of plates used for fracture stabilization in small dogs and cats. Vet Surg 2006; 35: 573-578.