Can DCP and LCP plates generate more compression? The effect of multiple eccentrically placed screws and their drill positioning guides

Yaish, F.; Nanu, A.; Cross, A.T.

doi:10.1016/j.injury.2011.02.012

Cited by 17 publications

(27 citation statements)

References 9 publications

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“…For the DCP fixation model, the screw head is in contact with the plate and the plate is in contact with the bone, with a friction coefficient of 0.2 and 0.3, respectively . The screw tightening preload of 300N was used according to the literature to tighten the screw . For the LCP, a bone‐plate off‐set of 2 mm was used .…”

Section: Methodsmentioning

confidence: 99%

Bone resorption triggered by high radial stress: The mechanism of screw loosening in plate fixation of long bone fractures

Feng

Lin

Fang

et al. 2019

Journal Orthopaedic Research

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Screw loosening is a common complication in plate fixation. However, the underlying mechanism is unclear. This study investigated screw loosening mechanisms by finite element analysis (FEA) simulation and clinical X‐ray feature analysis. Two FEA models incorporated bone heterogeneity and orthotropy, representing fracture fixation using dynamic compression plate (DCP) and locking compression plate (LCP), were developed. These models were used to examine the volume of bone exceeding a certain stress value around each screw under physiologically‐relevant loading conditions. These damaged bone was then separated and compared by the axial stress and radial stress of each screw. In addition, features of patients’ X‐ray images showing screw loosening were analyzed to validate the loosening features simulated by the models. The FEA study showed that more damaged bone was found at the central two screws which gradually decreased toward the two end screws in all groups. More bone was damaged by the radial stress of each screw than by the axial stress. The radiological analysis of screw loosening showed that bone loss occurred at the screw closest to the fracture line first then subsequent bone loss at the screws further away from the fracture line occurred. This study found that the two screws nearest to the fracture line are more vulnerable to loosening. The radial stress of the screw plays a larger role in screw loosening than the axial stress. Bone resorption triggered by the high radial stress of screws is indicated as the mechanism of screw loosening in the diaphyseal plate fixation. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:1498–1507, 2019.

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Section: Methodsmentioning

confidence: 99%

Bone resorption triggered by high radial stress: The mechanism of screw loosening in plate fixation of long bone fractures

Feng

Lin

Fang

et al. 2019

Journal Orthopaedic Research

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“…This novel application induces normal stresses in the axial direction of the screw and does not require any artificial constraints or prescribed displacements. Values of preload vary widely in the literature; a value of 500 N was chosen based on an average of some (Rybicki and Simonen 1977;Zand et al 1983;Cheal et al 1985;Beaupre et al 1988;Perren 2002;Kim et al 2010;Ya'ish et al 2011). In the DCP models where the fracture was completely reduced, this approach was also used to simulate a 500 N tensile preload in the plate (Figure 3(b)).…”

Section: Methodsmentioning

confidence: 99%

Reasons why dynamic compression plates are inferior to locking plates in osteoporotic bone: a finite element explanation

MacLeod

Simpson

Pankaj

2014

Computer Methods in Biomechanics and Biomedical Engineering

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While locking plate fixation is becoming increasingly popular for complex and osteoporotic fractures, for many indications compression plating remains the standard choice. This study compares the mechanical behaviour of the more recent locking compression plate (LCP) device, with the traditional dynamic compression plates (DCPs) in bone of varying quality using finite element modelling. The bone properties considered include orthotropy, inhomogeneity, cortical thinning and periosteal apposition associated with osteoporosis. The effect of preloads induced by compression plating was included in the models. Two different fracture scenarios were modelled: one with complete reduction and one with a fracture gap. The results show that the preload arising in DCPs results in large principal strains in the bone all around the perimeter of the screw hole, whereas for LCPs large principal strains occur primarily on the side of the screw proximal to the load. The strains within the bone produced by the two screw types are similar in healthy bone with a reduced fracture gap; however, the DCP produces much larger strains in osteoporotic bone. In the presence of a fracture gap, the DCP results in a considerably larger region with high tensile strains and a slightly smaller region with high compressive strains. These findings provide a biomechanical basis for the reported improved performance of locking plates in poorer bone quality.

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“…A number of mechanical studies have aided in the understanding of the DCP technique. Ya’ish et al 8 used cylindrical bone analogs to demonstrate that the addition of any more than two eccentrically placed screws on the same side of the fracture produced no further compression across the fracture site. In the mid-1980s, Cheal et al 9,10 demonstrated that nonuniform compression could arise with DCP use.…”

Section: Femoral Shaft Fracture Dynamic Compression Plating Digitalmentioning

confidence: 99%

Pre-bending a dynamic compression plate significantly alters strain distribution near the fracture plane in the mid-shaft femur

Ristow

Mead

Cordeiro

et al. 2020

Proc Inst Mech Eng H

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This study evaluated the effect of pre-bending dynamic compression plates on fracture site compression. Recommendations of 1 to 2 mm of pre-bend have been proposed, but there does not appear to be experimental data to confirm the optimal pre-bend magnitude. Dynamic compression plating was performed on the lateral convex surface of 18 femoral analogs to fixate a simulated mid-shaft fracture. Plates with 0 mm (flat plate), 1 mm, and 2 mm of pre-bend were evaluated for their production of compression by determining the strain magnitudes for 10 equal-sized zones across the anterior cortex at the osteotomy site using digital imaging correlation. The 0 and 1 mm plates produced significantly more compression at the near cortex (p = 0.001 and p = 0.003, respectively) than the 2 mm plate. However, the 0 and 1 mm plates also created visible diastasis at the far cortex, while the 2 mm plate exhibited compression across all zones. The strain magnitudes for the 0 mm (R2 = 0.62) and 1 mm (R2 = 0.86) plates linearly and significantly decreased from the region adjacent to the plate until a region 50%–60% across the analog diameter. In contrast, the 2 mm plate exhibited uniform strains across the osteotomy site. This study demonstrates that pre-bending a dynamic compression plate 2 mm prior to fixation on a convex lateral femur provides the most compression at the far cortex. It also produces more uniform compression across the fracture when compared to 0 and 1 mm of pre-bend.

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Can DCP and LCP plates generate more compression? The effect of multiple eccentrically placed screws and their drill positioning guides

Cited by 17 publications

References 9 publications

Bone resorption triggered by high radial stress: The mechanism of screw loosening in plate fixation of long bone fractures

Bone resorption triggered by high radial stress: The mechanism of screw loosening in plate fixation of long bone fractures

Reasons why dynamic compression plates are inferior to locking plates in osteoporotic bone: a finite element explanation

Pre-bending a dynamic compression plate significantly alters strain distribution near the fracture plane in the mid-shaft femur

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