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Zhang S, Patel D, Brady M, Gambill S, Theivendran K, Deshmukh S, Swadener J, Junaid S, Leslie LJ. Experimental testing of fracture fixation plates: A review. Proc Inst Mech Eng H 2022; 236:1253-1272. [PMID: 35920401 PMCID: PMC9449446 DOI: 10.1177/09544119221108540] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Metal and its alloys have been predominantly used in fracture fixation for
centuries, but new materials such as composites and polymers have begun to see
clinical use for fracture fixation during the past couple of decades. Along with
the emerging of new materials, tribological issues, especially debris, have
become a growing concern for fracture fixation plates. This article for the
first time systematically reviews the most recent biomechanical research, with a
focus on experimental testing, of those plates within ScienceDirect and PubMed
databases. Based on the search criteria, a total of 5449 papers were retrieved,
which were then further filtered to exclude nonrelevant, duplicate or
non-accessible full article papers. In the end, a total of 83 papers were
reviewed. In experimental testing plates, screws and simulated bones or cadaver
bones are employed to build a fixation construct in order to test the strength
and stability of different plate and screw configurations. The test set-up
conditions and conclusions are well documented and summarised here, including
fracture gap size, types of bones deployed, as well as the applied load, test
speed and test ending criteria. However, research on long term plate usage was
very limited. It is also discovered that there is very limited experimental
research around the tribological behaviour particularly on the debris’
generation, collection and characterisation. In addition, there is no identified
standard studying debris of fracture fixation plate. Therefore, the authors
suggested the generation of a suite of tribological testing standards on
fracture fixation plate and screws in the aim to answer key questions around the
debris from fracture fixation plate of new materials or new design and
ultimately to provide an insight on how to reduce the risks of debris-related
osteolysis, inflammation and aseptic loosening.
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Affiliation(s)
- Shiling Zhang
- Aston Institute of Materials Research (AIMR), Aston University, Birmingham, UK
| | - Dharmesh Patel
- Invibio Biomaterial Solutions Limited, Hillhouse International, Thornton-Cleveleys, UK
| | - Mark Brady
- Invibio Biomaterial Solutions Limited, Hillhouse International, Thornton-Cleveleys, UK
| | - Sherri Gambill
- Invibio Biomaterial Solutions Limited, Hillhouse International, Thornton-Cleveleys, UK
| | | | - Subodh Deshmukh
- Sandwell and West Birmingham Hospital NHS Trust, Birmingham, UK
| | - John Swadener
- Aston Institute of Materials Research (AIMR), Aston University, Birmingham, UK
| | - Sarah Junaid
- Aston Institute of Materials Research (AIMR), Aston University, Birmingham, UK
| | - Laura Jane Leslie
- Aston Institute of Materials Research (AIMR), Aston University, Birmingham, UK
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Palierne S, Blondel M, Swider P, Autefage A. Biomechanical Comparison of Use of Two Screws versus Three Screws Per Fragment with Locking Plate Constructs under Cyclic Loading in Compression in a Fracture Gap Model. Vet Comp Orthop Traumatol 2022; 35:166-174. [PMID: 35272366 DOI: 10.1055/s-0042-1744175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
OBJECTIVES The aim of this study was to measure and compare the stiffness and cyclic fatigue of two plate-bone model constructs, with either two or three locking screws per fragment, under cyclic compression. METHODS A 10-hole 3.5 mm stainless steel locking compression plate (LCP) was fixed 1 mm from a synthetic bone model in which the fracture gap was 47 mm. Two groups of 10 constructs, prepared with either two or three bicortical locking screws placed at the extremities of each fragment, were tested in a load-controlled compression test until failure. RESULTS The three-screw constructs were stiffer than the two-screw constructs (196.75 ± 50.48 N/mm and 102.43 ± 22.93 N/mm, respectively) and the actuator displacements of the two-screw constructs were higher (18.02 ± 1.07 mm) than those of the three-screw constructs (14.48 ± 2.25 mm). The number of cycles to failure of the two-screw constructs was significantly lower (38,337.50 ± 2,196.98) than the that of the three-screw constructs (44,224.00 ± 1,515.24). Load at irreversible deformation was significantly lower in the two-screw constructs (140.93 ± 13.39 N) than in the three-screw constructs (184.27 ± 13.17 N). All constructs failed by plate bending at the gap between the two cylinders. CLINICAL SIGNIFICANCE Omission of the third innermost locking screw during bridging osteosynthesis subjected to compression forces led to a 13.3% reduction in the number of cycles to failure and a 23.5% reduction of the load withstood by the plate before plastic deformation occurred.
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Affiliation(s)
| | | | - Pascal Swider
- Université de Toulouse, IMFT UMR 5502, Toulouse, France
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Muro NM, Gilley RS, Kemper AR, Benitez ME, Barry SL, McNally C. Stiffness of a type II external skeletal fixator and locking compression plate in a fracture gap model. Vet Surg 2021; 50:622-632. [PMID: 33404123 DOI: 10.1111/vsu.13563] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 10/29/2020] [Accepted: 11/28/2020] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To compare the stiffness of constructs fixed with a type II external skeletal fixator (ESF) or a 3.5-mm locking compression plate (LCP) in axial compression and bending with a fracture gap model. STUDY DESIGN Quasi-static four-point bending and axial compression tests. SAMPLE POPULATION Ten LCP and 10 ESF immobilizing epoxy cylinders with a 40-mm fracture gap. METHODS Five constructs of each type were tested in nondestructive mediolateral (ML) four-point bending and then rotated and tested in nondestructive craniocaudal (CC) four-point bending. Five additional constructs of each type were tested in nondestructive axial compression. Stiffness was compared between loading modes by construct type and between construct types by loading mode. RESULTS Type II ESF were stiffer than LCP in ML bending (difference, 1474 N/mm, P < .0001) and in axial compression (difference, 458 N/mm, P = .008) but not in CC bending (P = .1673). Type II ESF were stiffer in ML bending than in CC bending (difference, 999 N/m, P < .0001), while LCP were stiffer in CC bending than in ML bending (difference, 634 N/mm, P < .0001). CONCLUSION Type II ESF generated stiffer constructs compared with LCP in ML bending and in axial compression without a difference in CC bending. External skeletal fixator and LCP bending stiffness varied by loading direction. CLINICAL SIGNIFICANCE A type II ESF should be considered in a comminuted fracture requiring increased stability in ML and axial directions.
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Affiliation(s)
- Noelle M Muro
- Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia
| | - Robert S Gilley
- Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia.,College of Veterinary Medicine, Lincoln Memorial University, Harrogate, Tennessee
| | - Andrew R Kemper
- Department of Biomedical Engineering and Mechanics, Center for Injury Biomechanics, Virginia Tech, Blacksburg, Virginia
| | - Marian E Benitez
- Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia
| | - Sabrina L Barry
- Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, Virginia
| | - Craig McNally
- Department of Biomedical Engineering and Mechanics, Center for Injury Biomechanics, Virginia Tech, Blacksburg, Virginia
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Effect of monocortical and bicortical screw numbers on the properties of a locking plate-intramedullary rod configuration. Vet Comp Orthop Traumatol 2017; 29:459-465. [DOI: 10.3415/vcot-16-03-0040] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Accepted: 07/12/2016] [Indexed: 11/17/2022]
Abstract
SummaryObjectives: To evaluate the effect of varying the number and configuration of locking bicortical and monocortical screws on a plate-rod construct using a mid-diaphyseal femoral ostectomy model.Methods: Thirty Greyhound femurs were assigned to six groups (A-F). An intramedullary pin was placed in each bone following which a 3.5 mm locking plate was applied with six differing locking screw configurations. Groups A to C had one bicortical screw in the most proximal and distal plate holes and one to three monocortical locking screws in the proximal and distal fragments. Groups D to F had no bicortical screws placed and two to four monocortical locking screws in proximal and distal fragments. Each construct was axially loaded at 4 Hz from a preload of 10 Newtons (N) to 72 N, increasing to 144 N and 216 N, each of 6000 cycles with a further 45,000 cycles at 216 N to simulate a three to six week postoperative convalescence period. Constructs were then loaded to failure.Results: No construct suffered screw loosening or a significant change in construct stiffness during cyclic loading. There was no significant difference in load to failure of any construct (p = 0.34), however, less variation was seen with monocortical constructs. All constructs failed at greater than 2.5 times physiological load, and failure was by bending of the intramedullary pin and plate rather than screw loosening or pull-out.Clinical significance: Axially loaded locking monocortical plate-rod constructs applied to the canine femur may confer no difference biomechanically to those employing locking bicortical screws.
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Tremolada G, Lewis DD, Paragnani KL, Conrad BP, Kim SE, Pozzi A. Biomechanical comparison of a 3.5-mm conical coupling plating system and a 3.5-mm locking compression plate applied as plate-rod constructs to an experimentally created fracture gap in femurs of canine cadavers. Am J Vet Res 2017; 78:712-717. [PMID: 28541152 DOI: 10.2460/ajvr.78.6.712] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
OBJECTIVE To compare stiffness and resistance to cyclic fatigue of two 3.5-mm locking system plate-rod constructs applied to an experimentally created fracture gap in femurs of canine cadavers. SAMPLE 20 femurs from cadavers of 10 mixed-breed adult dogs. PROCEDURES 1 femur from each cadaver was stabilized with a conical coupling plating system-rod construct, and the contralateral femur was stabilized with a locking compression plate (LCP)-rod construct. An intramedullary Steinmann pin was inserted in each femur. A 40-mm gap then was created; the gap was centered beneath the central portion of each plate. Cyclic axial loading with increasing loads was performed. Specimens that did not fail during cyclic loading were subjected to an acute load to failure. RESULTS During cyclic loading, significantly more LCP constructs failed (6/10), compared with the number of conical coupling plating system constructs that failed (1/10). Mode of failure of the constructs included fracture of the medial or caudal aspect of the cortex of the proximal segment with bending of the plate and pin, bending of the plate and pin without fracture, and screw pullout. Mean stiffness, yield load, and load to failure were not significantly different between the 2 methods of stabilization. CONCLUSIONS AND CLINICAL RELEVANCE Both constructs had similar biomechanical properties, but the conical coupling plating system was less likely to fail than was the LCP system when subjected to cyclic loading. These results should be interpreted with caution because testing was limited to a single loading mode.
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Lin ASP, Fechter CM, Magill M, Wipf F, Moore T, Guldberg RE. The effect of contouring on fatigue resistance of three types of fracture fixation plates. J Orthop Surg Res 2016; 11:107. [PMID: 27671529 PMCID: PMC5037585 DOI: 10.1186/s13018-016-0439-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Accepted: 09/06/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Metallic reconstruction plates used for fracture stabilization typically require intraoperative contouring for patient-specific anatomical fit. Despite this, characterization of plate mechanical properties after contouring has previously been limited. The objective of this study was to assess whether contouring affects fatigue resistance for three types of Stryker seven-hole stainless steel (SS) 316LVM fracture fixation plates. The hypothesis was that for each plate type, more contouring repetitions would result in lower fatigue resistance. METHODS Plates were contoured using a bench-top plate bender to ±20° either 0×, 3×, 6×, or 9× (n = 5 per group) and tested in the straight configuration. Cyclic four-point bending was applied in an incremental stepwise staircase approach (one step = 100,000 cycles, 10 Hz) until failure (defined as brittle fracture or plastic deformation of 10° permanent bend). Moment-cycle product (MCP) was computed as the summation of maximum moment × number of cycles and used as the primary measure of fatigue resistance. RESULTS No significant differences in fatigue resistance were detected between contouring groups for Basic Fragment Set (BFS) Reconstruction Plates. Significantly lower fatigue resistance was measured for 9× contoured Matta Pelvic System (MPS) Straight Plates compared to 0× contoured plates (p = 0.023). MPS Flex Plates contoured 3× had greater fatigue resistance than 0× contoured (p = 0.031) and 9× contoured plates (p = 0.032). CONCLUSIONS This work provides fatigue resistance-based evidence that clinicians should avoid high repetitions of contouring for MPS Straight Plates. Meanwhile, BFS Reconstruction Plates and MPS Flex Plates are not negatively affected by contouring. These results allow for improved intraoperative decisions about using or discarding plates after multiple contouring repetitions.
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Affiliation(s)
- Angela S P Lin
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801 Ferst Dr., Atlanta, GA, 30332, USA. .,Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, 315 Ferst Dr. NW, Atlanta, GA, 30332, USA.
| | - Chelsea M Fechter
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, 313 Ferst Dr., Atlanta, GA, 30332, USA
| | - Mark Magill
- Department of Orthopaedics-Trauma, Emory University School of Medicine, 80 Jesse Hill Jr. Dr. SE, Atlanta, GA, 30303, USA
| | - Felix Wipf
- Stryker Trauma AG, Dr. Homer Stryker Str. 1, 2545, Selzach, Switzerland
| | - Thomas Moore
- Department of Orthopaedics-Trauma, Emory University School of Medicine, 80 Jesse Hill Jr. Dr. SE, Atlanta, GA, 30303, USA
| | - Robert E Guldberg
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801 Ferst Dr., Atlanta, GA, 30332, USA.,Parker H. Petit Institute for Bioengineering & Bioscience, Georgia Institute of Technology, 315 Ferst Dr. NW, Atlanta, GA, 30332, USA
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Matres-Lorenzo L, Diop A, Maurel N, Boucton MC, Bernard F, Bernardé A. Biomechanical Comparison of Locking Compression Plate and Limited Contact Dynamic Compression Plate Combined with an Intramedullary Rod in a Canine Femoral Fracture-Gap Model. Vet Surg 2016; 45:319-26. [PMID: 26909507 DOI: 10.1111/vsu.12451] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To compare the biomechanical properties of locking compression plate (LCP) and a limited contact dynamic compression plate combined with an intramedullary rod (LC-DCP-R) in a cadaveric, canine, femoral fracture-gap model. STUDY DESIGN In vitro biomechanical study; nonrandomized, complete block (dog). SAMPLE POPULATION Paired cadaveric canine femora (n = 10 dogs). METHODS Paired femurs with a mid-diaphyseal 20 mm gap were stabilized with either LCP or LC-DCP-R. Nondestructive testing up to 60% of body weight (BW) was followed by a continuous destructive test. Comparative structural properties, 3-dimensional (3D) interfragmentary motion, and plate linear strain were evaluated. Paired comparisons were made between LCP and LC-DCP-R. RESULTS Stiffness after nondestructive testing was significantly lower for LCP with a mean (95% confidence interval [CI]) of 61 N/mm (46-76) versus 89 N/mm (67-110) for LC-DCP-R (P = .0072). Ultimate load to failure was significantly lower for LCP with a median (interquartile range [IQR]) of 270 N (247-286) versus 371.5 (353-385) for LC-DCP-R (P = .002). Axial motion at 60% BW was significantly higher for LCP with a median (IQR) of 1.01 mm (0.71-1.26) versus 0.36 mm (0.20-0.49) for LC-DCP-R (P = .002). Shear motion was significantly higher for LCP with a median (IQR) of 1.18 (0.78-1.58) versus 0.72 mm (0.45-1.00) for LC-DCP-R (P = .018). Strain was significantly higher for mid-LCP surface with a mean (95%CI) at 60% BW of 979 μdef (579-1378) versus 583 μdef (365-801) at mid-LC-DCP-R surface (P = .0153). The elastic limit strain of the plates was not different and was reached at a mean (95%CI) load of 241 N (190-292) for LCP versus 290 N (245-336) for LC-DCP-R (P = .12). CONCLUSION The LC-DCP-R showed higher stiffness and resistance to failure, lower interfragmentary motion, and lower plate strain and stress compared to LCP.
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Affiliation(s)
| | - Amadou Diop
- Equipe Biomécanique et Remodelage Osseux (EPBRO), École Nationale Supérieure d'Arts et Métiers, Paris, France
| | - Nathalie Maurel
- Equipe Biomécanique et Remodelage Osseux (EPBRO), École Nationale Supérieure d'Arts et Métiers, Paris, France
| | - Marie-Charlotte Boucton
- Equipe Biomécanique et Remodelage Osseux (EPBRO), École Nationale Supérieure d'Arts et Métiers, Paris, France
| | - Fabrice Bernard
- Centre Hospitalier Vétérinaire Saint-Martin, Saint Martin Bellevue, France
| | - Antoine Bernardé
- Centre Hospitalier Vétérinaire Saint-Martin, Saint Martin Bellevue, France
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Effect of bending direction on the mechanical behaviour of 3.5 mm String-of-Pearls and Limited Contact Dynamic Compression Plate constructs. Vet Comp Orthop Traumatol 2015; 28:433-40. [PMID: 26449348 DOI: 10.3415/vcot-15-01-0013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2015] [Accepted: 07/30/2015] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To compare the bending properties of String-of-Pearls® (SOP) and Limited Contact Dynamic Compression Plate® (LC-DCP) constructs in orthogonal bending directions. METHODS 3.5 mm SOP and LC-DCP plates were fixed to a bone model simulating a comminuted tibial fracture. Specimens were non-destructively tested in both mediolateral and craniocaudal bending for 10 cycles. Bending stiffness and total angular deformation were compared using parametric analyses (p <0.05). RESULTS For both constructs, stiffness was significantly less when bending moments were applied against the thickness of the plates (mediolateral bending) than against the width (craniocaudal bending). When compared to the mediolateral plane, bending constructs in the craniocaudal plane resulted in a 49% (SOP group) and 370% (LC-DCP group) increase in stiffness (p <0.001). Mediolateral bending stiffness was significantly greater in the SOP than the LC-DCP constructs. Conversely, in craniocaudal bending, SOP constructs stiffness was significantly less than that of the LC-DCP constructs. The differences between the two constructs in total angular deformation had an identical pattern of significance. CLINICAL SIGNIFICANCE This study found that SOP showed less variability between the orthogonal bending directions than LC-DCP in a comminuted fracture model, and also described the bi-planar bending behaviour of both constructs. Although not exhibiting identical bending properties in both planes, SOP constructs had a more homogenous bending behaviour in orthogonal loading directions. The difference between the SOP with a circular cross sectional shape compared to the rectangular shape of standard plates is probably responsible for this difference.
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Minto B, Prada T, Marinho P, Zani C, Menezes M. Successful use of autogenous bone graft for the treatment of a radius-ulna nonunion in an amputee dog. ARQ BRAS MED VET ZOO 2015. [DOI: 10.1590/1678-4162-8054] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Fracture nonunions represent important complications in orthopedic surgeries. Nonunion repairs or bone defects are surgically challenging. Our aim was to describe a nonunion case, which was repaired with rapid bone recovery. An 8-month-old male mixed breed dog that has been previously operated was presented to the Veterinary Medical Teaching Hospital of São Paulo State University, with a right radius-ulna nonunion and an amputated contralateral forelimb. A cancellous bone graft was collected from a partially amputated limb, in order to correct the nonunion, and used in association with a locking plate. After four weeks, the bone graft had been incorporated into the original bone. Clinical union with good weight bearing was achieved after eight weeks.
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Affiliation(s)
| | | | | | - C.C. Zani
- Universidade Estadual Paulista, Brazil
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Mechanical performance in axial compression of a titanium polyaxial locking plate system in a fracture gap model. Vet Comp Orthop Traumatol 2015; 28:88-94. [PMID: 25703709 DOI: 10.3415/vcot-14-03-0046] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Accepted: 12/11/2014] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To evaluate the bending strength of the VetLOX® polyaxial locking plate system. MATERIALS AND METHODS Thirty-five 3.5 mm 12-hole titanium VetLOX® plates were used to stabilize seven different construct designs in a 1 cm fracture gap simulation model. Each construct was subjected to axial compression. Mean bending stiffness (BS) and yield load (YL) of each construct design were analysed using a one-way ANOVA and Tukey post-hoc analysis. Screw angulation was measured on reconstructed computed tomography (CT) images. RESULTS Reducing plate working length for fixed-angle constructs significantly increased BS (p <0.01) and YL (p <0.01). For a constant plate working length, increasing screw number did not significantly affect BS (p = 1.0) or YL (p = 0.86). Screw angulation measurement technique was validated by intra-class correlation coefficients (ICC) (ICC >0.9 for inter- and intra-observer measurements). An average screw angle of 13.2° did not significantly affect mechanical performance although incomplete screw head-plate engagement was noted on some reconstructed CT images when angulation exceeded 10°. Prefabricated screw-head inserts did not significantly increase mechanical performance. A 4 mm bone-plate stand-off distance significantly reduced BS and YL by 63% and 69% respectively. CLINICAL RELEVANCE The VetLOX® system allows the benefits of polyaxial screw insertion whilst maintaining comparable bending properties to fixed angle insertion. The authors recommend accurate plate contouring to reduce the risk of plate bending.
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Petersen W, Wall A, Paulin T, Park HU, Heymann L. Stability of two angular stable locking plates for open wedge high tibial osteotomy (HTO): TomoFix™ versus LOQTEQ® HTO plate. Arch Orthop Trauma Surg 2014; 134:1437-42. [PMID: 25015791 DOI: 10.1007/s00402-014-2042-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Indexed: 11/24/2022]
Abstract
INTRODUCTION The aim of this study was to test the mechanical stability of LOQTEQ® HTO plate in comparison to the TomoFix™ internal plate fixator. MATERIALS AND METHODS An unstable fracture gap model with two standardized polyoxymethylene (POM) cylinders was used for this study. With this model 5 LOQTEQ® HTO plates and 5 TomoFix™ were cyclically loaded. The start load was 100 N and increased by 50 N after each successful completed cycle. Each load step included 250,000 cycles. All tests were performed in accordance with the American Society for Testing and Materials (ASTM) Standard Specification and Test Method for Metallic Bone Plates F382-99(2003)e1. RESULTS The mean fatigue strength of the LOQTEQ® HTO Plate was 155 % of the value gained by the TomoFix™ implant. This difference was statistically significant (t test <0.001). There was also a significant difference in the cycles but both implants survived. The LOQTEQ® HTO Plate system survived 1,520,336.8 (±121,687.7) cycles, whereas the TomoFix™ group passed on average 847,802,600 (±134,660.7) cycles. In both groups, the only failure mode was plate breakage in a shaft hole. CONCLUSIONS The results of the present study showed that fatigue strength of the LOQTEQ® HTO plate was significantly higher in comparison to TomoFix™. These results justify the clinical use of the LOQTEQ® HTO plate.
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Affiliation(s)
- Wolf Petersen
- Department of Trauma and Orthopaedic Surgery, Martin Luther Hospital, Caspar Theyss Straße 27-31, Grunewald, 14193, Berlin, Germany,
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