The objective of this study was to compare the Locking Compression Plate (LCP) with the more cost-effective straight-dynamic compression plate (DCP) and wave-DCPs by testing in vitro the effects of plate stiffness on different types of diaphyseal femur fractures (A, B, and C, according to AO classification). The bending structural stiffness of each plate was obtained from four-point bending tests according to ASTM F382-99(2008). The plate systems were tested by applying compression/bending in different osteosynthesis simulation models using wooden rods to simulate the fractured bone fragments. Kruskal-Wallis test showed no significant difference in the bending structural stiffness between the three plate models. Rank-transformed two-way ANOVA showed significant influence of plate type, fracture type, and interaction plate versus fracture on the stiffness of the montages. The straight-DCP produced the most stable model for types B and C fractures, which makes its use advantageous for complex nonosteoporotic fractures that require minimizing focal mobility, whereas no difference was found for type A fracture. Our results indicated that DCPs, in straight or wave form, can provide adequate biomechanical properties for fixing diaphyseal femoral fractures in cases where more modern osteosynthesis systems are cost restrictive. 1. Introduction The current standard of care for femoral fractures is the intramedullary nail, but there are situations in which the use of plates is indicated, like narrow medullary cavity, bone deformities, and open growth plate. Metal plates have been used for the fixation of fractures since the end of the 19th century. The DCP, designed with oblong holes to provide interfragmentary compression when tightening the screws, was introduced in 1969 [1]. At that time, researchers believed that “absolute” stability was the best method for treating long bone diaphyseal fractures, but a high rate of nonunions and postoperative infections questioned this concept only a few decades later [2–4]. As opposed to the wide surgical approach required by this technique, it has been suggested that less manipulation of the bone fragments would result in faster bone healing by preserving the fracture site vasculature [5]. Consequently, osteosynthesis techniques were modified [2, 4, 6–8] to minimize damage to the soft tissue and periosteum in order to preserve the fracture vascularization [2, 7]. The authoritative work of Heitemeyer et al. [9] demonstrated that this new protocol improved complex fracture healing of the femur diaphysis. Appropriate stress
References
[1]
H. K. Uhthoff, P. Poitras, and D. S. Backman, “Internal plate fixation of fractures: short history and recent developments,” Journal of Orthopaedic Science, vol. 11, no. 2, pp. 118–126, 2006.
[2]
C. Kinast, B. R. Bolhofner, J. W. Mast, and R. Ganz, “Subtrochanteric fractures of the femur,” Clinical Orthopaedics and Related Research, vol. 238, pp. 122–130, 1989.
[3]
S. M. Perren, M. Allgower, H. Brunner et al., “The concept of biological plating using the limited contact-dynamic compression plate (LC-DCP): scientific background, design and application,” Injury, vol. 22, no. 1, pp. 1–41, 1991.
[4]
S. M. Perren, K. Klaue, O. Pohler, et al., “The limited contact dynamic compression plate (LC-DCP),” Archives of Orthopaedic and Trauma Surgery, vol. 109, no. 6, pp. 304–310, 1990.
[5]
S. M. Perren, “Evolution of the internal fixation of long bone fractures. The scientific basis of biological internal fixation: choosing a new balance between stability and biology,” Journal of Bone and Joint Surgery, vol. 84, no. 8, pp. 1093–1110, 2002.
[6]
J. P. Chrisovitsinos, T. Xenakis, et al., “Bridge plating osteosynthesis of 20 comminuted fractures of the femur,” Acta Orthopaedica Scandinavica Supplementum, vol. 275, pp. 72–76, 1997.
[7]
C. Gerber, J. W. Mast, and R. Ganz, “Biological internal fixation of fractures,” Archives of Orthopaedic and Trauma Surgery, vol. 109, no. 6, pp. 295–303, 1990.
[8]
J. Schatzkei, “Fractures of the distal femur revisited,” Clinical Orthopaedics and Related Research, vol. 347, pp. 43–56, 1998.
[9]
U. Heitemeyer, F. Kemper, G. Hierholzer, and J. Haines, “Severely comminuted femoral shaft fractures: treatment by bridging-plate osteosynthesis,” Archives of Orthopaedic and Traumatic Surgery, vol. 106, no. 5, pp. 327–330, 1987.
[10]
L. E. Claes and C. A. Heigele, “Magnitudes of local stress and strain along bony surfaces predict the course and type of fracture healing,” Journal of Biomechanics, vol. 32, no. 3, pp. 255–266, 1999.
[11]
G. Blatter, B. Gasser, and B. G. Weber, “Die Wellenplatte,” AO-Bulletin, Version 29, 1989.
[12]
G. Blatter and B. G. Weber, “Wave plate osteosynthesis as a salvage procedure,” Archives of Orthopaedic and Trauma Surgery, vol. 109, no. 6, pp. 330–333, 1990.
[13]
D. Ring, J. B. Jupiter, R. A. Sanders et al., “Complex nonunion of fractures of the femoral shaft treated by wave-plate osteosynthesis,” Journal of Bone and Joint Surgery B, vol. 79, no. 2, pp. 289–294, 1997.
[14]
M. Wagner, “General principles for the clinical use of the LCP,” Injury, vol. 34, no. 2, pp. SB31–SB42, 2003.
[15]
C. Sommer, E. Gautier, M. Müller, D. L. Helfet, and M. Wagner, “First clinical results of the locking compression plate (LCP),” Injury, vol. 34, no. 2, pp. SB43–SB54, 2003.
[16]
K. Stoffel, U. Dieter, G. Stachowiak, A. G？chter, and M. S. Kuster, “Biomechanical testing of the LCP—how can stability in locked internal fixators be controlled?” Injury, vol. 34, no. 2, pp. SB11–SB19, 2003.
[17]
A. J. Angelini, B. Livani, M. A. Flierl, S. J. Morgan, and W. D. Belangero, “Less invasive percutaneous wave plating of simple femur shaft fractures: a prospective series,” Injury, vol. 41, no. 6, pp. 624–628, 2010.
[18]
M. E. Müller, S. Nazarian, et al., The Comprehensive Classification of Fractures of Long Bonesed, Springer, Berlin, Germany, 1st edition, 1990.
[19]
ASTM Standard, “Standard specification and test method for metallic bone plates,” West Conshohocken F382-99, ASTM International, 2008.
[20]
K. E. Kojima, J. S. Hungria Neto, and P. M. M. B. Fucs, “In vitro evaluation of the influence of the wave length and height in the wave-plate osteosynthesis,” Archives of Orthopaedic and Trauma Surgery, vol. 130, no. 9, pp. 1133–1139, 2010.
[21]
J. Cordey, M. Borgeaud, and S. M. Perren, “Force transfer between the plate and the bone: relative importance of the bending stiffness of the screws and the friction between plate and bone,” Injury, vol. 31, no. 3, pp. S-C21–C28, 2000.
[22]
A. J. Angelini, Ensaio mecanico de compress？o estática comparada entre placas retas e pré-moldadas em onda [Ph.D. dissertation], University of Campinas, Campinas, Brazil, 2001.
[23]
M. Wagner, F. Knorr-Held, and D. Hohmann, “Measuring stability of wire cerclage in femoral fractures when performing total hip replacement. In vitro study on a standardized bone model,” Archives of Orthopaedic and Trauma Surgery, vol. 115, no. 1, pp. 33–37, 1996.
[24]
E. F. Carrera, F. A. Nicolao, N. A. Netto, R. L. Carvalho, F. B. dos Reis, and E. J. Giordani, “A mechanical comparison between conventional and modified angular plates for proximal humeral fractures,” Journal of Shoulder and Elbow Surgery, vol. 17, no. 4, pp. 631–636, 2008.
[25]
J. L. Norris, K. H. Kraus, and J. P. O'Leary, “Effect of a supplemental plate on the stiffness of a type I external fixator,” Veterinary Surgery, vol. 31, no. 2, pp. 133–137, 2002.
[26]
I. A. Karnezis, “Biomechanical considerations in “biological” femoral osteosynthesis: an experimental study of the ”bridging” and “wave” plating techniques,” Archives of Orthopaedic and Trauma Surgery, vol. 120, no. 5-6, pp. 272–275, 2000.
[27]
K. Str？ms？e, “Fracture fixation problems in osteoporosis,” Injury, vol. 35, no. 2, pp. 107–113, 2004.
[28]
M. Snow, G. Thompson, and P. G. Turner, “A mechanical comparison of the locking compression plate (LCP) and the low contact-dynamic compression plate (DCP) in an osteoporotic bone model,” Journal of Orthopaedic Trauma, vol. 22, no. 2, pp. 121–125, 2008.
