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Miller A. Mechanical Testing of Sliding on Pivot-Locking Clamp (SOP-LC) Fracture Repair System in Four-Point Bending and Torsion. Vet Comp Orthop Traumatol 2024. [PMID: 38698626 DOI: 10.1055/s-0043-1778682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/05/2024]
Abstract
OBJECTIVES The first objective of this study was to compare the mechanical performance of a straight and contoured rod for the sliding on pivot-locking clamp (SOP-LC) system. The second objective was to compare single-cycle bending and torsion of the SOP-LC rod-bone constructs to a bone gap model between two clamp configurations. STUDY DESIGN First experiment, 5 mm diameter rods from the 3.5 mm SOP-LC system, 4 straight and 4 bent rods were mechanically compared in four-point bending. The second experiment, 8 constructs with clamps on a single side of the rod and 8 constructs with clamps on alternating sides were compared in four-point bending and torsion. A torque limiting screwdriver at 2.5N was used for all constructs. RESULTS There were not significant differences between the noncontoured versus contoured rods. Constructs with clamps on a single side had a significantly higher yield load, yield displacement and bending strength, but the constructs with alternating clamps had a significantly higher initial torsional stiffness. There were no other significant differences. Mild clamp slippage and mild screw bending were noted in all the torsion tested constructs graphically with multiple stiffness slopes and visually on the post-tested constructs. CONCLUSION Torque applied to initial screw placement may play a role in reducing clamp slippage. Although bending yield load, bending yield displacement, bending strength and torsional stiffness were improved by different clamp placement, clinically this will depend on fracture type. Further studies are needed for clinical significance.
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Affiliation(s)
- Angel Miller
- TPLOVets, Rancho Santa Margarita, California, United States
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2
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Otaviano do Rego R, Dias BM, Manassero M, de Souza AF, De Zoppa ALDV, Ferrigno CRA. Locking conical coupling plates in small animal orthopedics: A review. Top Companion Anim Med 2023; 56-57:100827. [PMID: 37890581 DOI: 10.1016/j.tcam.2023.100827] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 08/27/2023] [Accepted: 10/22/2023] [Indexed: 10/29/2023]
Abstract
Conical coupling locking plates (CCP) have become an interesting alternative in veterinary orthopedics and traumatology. Available data in this regard, however, must be interpreted with caution, and several studies are still required to reach definitive conclusions on the clinical use of these implants. In this context, this review aims to discuss CCP applications and mechanical aspects in small animals and summarize in vivo, in vitro and ex vivo study results.
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Affiliation(s)
- Renato Otaviano do Rego
- Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, 87. Av. Dr. Orlando Marques de Paiva, São Paulo, SP 05508-270, Brazil.
| | - Bianca Marfil Dias
- Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, 87. Av. Dr. Orlando Marques de Paiva, São Paulo, SP 05508-270, Brazil
| | | | - Anderson Fernando de Souza
- Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, 87. Av. Dr. Orlando Marques de Paiva, São Paulo, SP 05508-270, Brazil
| | - André Luis do Valle De Zoppa
- Department of Surgery, Faculty of Veterinary Medicine and Animal Science, University of São Paulo, 87. Av. Dr. Orlando Marques de Paiva, São Paulo, SP 05508-270, Brazil
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Viitanen J, Quinn R, Allen M, Broeckx BJG, Bartkowiak T, Haimel G. Do locking plugs improve implant strength? Biomechanical comparison of polyaxial locking constructs with and without locking plugs in a fracture gap model. BMC Vet Res 2023; 19:104. [PMID: 37528435 PMCID: PMC10394762 DOI: 10.1186/s12917-023-03660-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/14/2023] [Indexed: 08/03/2023] Open
Abstract
BACKGROUND The objective of this study was to investigate the effects of locking plugs and the biomechanical properties of a 3.5 mm 8-hole polyaxial locking plate in a fracture gap model. Our hypothesis was that locking plugs would increase the strength and stiffness of the construct. Twelve 3.5 mm 8-hole plates were used to evaluate two different construct designs (with locking plugs vs. without locking plugs) with validated bone substitutes in a 25 mm bridging osteosynthesis gap model. Each construct was subjected to a single cycle four-point bending load to failure using a servo-hydraulic testing machine. Bending stiffness, bending strength, and bending structural stiffness were calculated and compared using an unpaired Student´s t-test. RESULTS The plating construct with locking plugs did not show any significant increase in terms of bending stiffness, bending strength, and bending structural stiffness compared to plating construct without locking plugs in a 25 mm gap fracture model during a single cycle four-point bending. CONCLUSIONS Under the conditions tested, filling empty plate holes with locking plugs in bridging osteosynthesis does not increase stiffness or strength of the plate-bone construct.
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Affiliation(s)
- Joni Viitanen
- Veterinary Specialists Scotland, part of Linnaeus veterinary limited, Livingston, EH54 8AG, United Kingdom.
| | - Robert Quinn
- Anderson Moores Veterinary Specialists, part of Linnaeus veterinary limited, Hampshire, S021 2LL, United Kingdom
| | - Matthew Allen
- Department of Veterinary Medicine, Surgical Discovery Centrum, University of Cambridge, Cambridge, CB3 0ES, United Kingdom
| | - Bart J G Broeckx
- Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, 9820, Merelbeke, Belgium
| | - Tomasz Bartkowiak
- Institute of Mechanical Technology, Poznan University of Technology, 60-965, Poznań, Poland
| | - Georg Haimel
- Tierarztpraxis Am Stadtpark, Reisnerstrasse7, 1030, Vienna, Austria
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4
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Kaczmarek J, Bartkowiak T, Paczos P, Zawadzki P, Łączna D, Gapiński B. What Is the Cost of Off-Axis Insertion of Locking Screws? A Biomechanical Comparison of a 3.5 mm Fixed-Angle and 3.5 mm Variable-Angle Stainless Steel Locking Plate Systems. Vet Comp Orthop Traumatol 2022; 35:339-346. [PMID: 35839838 DOI: 10.1055/s-0042-1750431] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
OBJECTIVE The aim of this study was to evaluate the effect of screw insertion angle and insertion torque on the mechanical properties of a 3.5 fixed-angle locking plate locking compression plate (LCP) and 3.5 variable-angle locking plate polyaxial locking system (PLS). METHODS In the LCP group, screws were placed abaxially at 0, 5 and 10 degrees. In the PLS group, screws were placed at 0, 5, 10, 15 and 20 degrees abaxially. The insertion torque was set to 1.5 and 2.5 Nm in the LCP and PLS groups respectively. A load was applied parallel to the screw axis, and the screw push-out force was measured until the locking mechanism was loosened. RESULTS The 3.5 LCP showed higher push-out strength than the 3.5 PLS when the screws were placed at 0 degree regardless of the insertion torque. The off-axis insertion of 3.5 LCP locking screws resulted in a significant decrease in push-out strength (p < 0.05). A higher insertion torque value significantly increased the screw holding strength for the 3.5 LCP (p < 0.05). The 3.5 PLS system had a significantly higher push-out force when the screws are at 0 degree than at 5, 10 and 15 degrees, and 20 degrees (p < 0.05) at any given insertion torque. An increase in the insertion torque did not have a significant effect on the push-out strength of the 3.5 PLS locking system. CONCLUSION The 3.5 PLS is more sensitive to the screw insertion angle than to the insertion torque, whereas the 3.5 LCP is affected by both factors. Placing 3.5 LCP locking screws off-axis significantly reduces the screw holding strength; therefore, this approach has to be avoided. The findings of our research indicate that a 1.5 Nm torque can be used for a 3.5 PLS.
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Affiliation(s)
| | - Tomasz Bartkowiak
- Poznan University of Technology, Faculty of Mechanical Engineering, Poznan , Poland
| | - Piotr Paczos
- Poznan University of Technology, Faculty of Mechanical Engineering, Poznan , Poland
| | - Paweł Zawadzki
- Poznan University of Technology, Faculty of Mechanical Engineering, Poznan , Poland
| | - Daria Łączna
- Poznan University of Technology, Faculty of Mechanical Engineering, Poznan , Poland
| | - Bartosz Gapiński
- Poznan University of Technology, Faculty of Mechanical Engineering, Poznan , Poland
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5
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Lee S, Ahmad N, Corriveau K, Himel C, Silva DF, Shamsaei N. Bending properties of additively manufactured commercially pure titanium (CPTi) limited contact dynamic compression plate (LC-DCP) constructs: Effect of surface treatment. J Mech Behav Biomed Mater 2021; 126:105042. [PMID: 34971952 DOI: 10.1016/j.jmbbm.2021.105042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 11/19/2021] [Accepted: 12/08/2021] [Indexed: 11/24/2022]
Abstract
Additive manufacturing of metallic materials, a layer-wise manufacturing method, is currently gaining attention in the biomedical industry because of its capability to fabricate complex geometries including customized parts fitting to patient requirements. However, one of the major challenges hindering the full implementation of additively manufactured parts in safety-critical applications is their poor mechanical performance under cyclic loading. This study investigated both quasi-static bending properties (bending stiffness, bending structural stiffness, and bending strength) and bending fatigue properties of additively manufactured (AM) commercially pure titanium (CPTi) limited contact dynamic compression plate (LC-DCP) constructs based on ASTM International standard for metallic bone plates (ASTM F382). In addition, the effect of post surface treatment methods including single shot-peened (SP), dual shot-peened (DP), and chemically assisted surface enhancement (CASE) on bending fatigue performance was also evaluated. Results indicated that bending stiffness and bending structural stiffness of AM CPTi LC-DCPs are comparable to conventionally manufactured (CM) counterparts; however, the bending strength of AM CPTi LC-DCPs is lower than CM counterparts. While the fatigue strength of as-built AM CPTi LC-DCPs is lower compared to the CM counterparts, AM CPTi LC-DCPs after post surface treatments (SP, DP, and CASE) exhibit statistically comparable fatigue strength to the CM CPTi LC-DCPs.
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Affiliation(s)
- Seungjong Lee
- National Center for Additive Manufacturing Excellence (NCAME), Auburn University, Auburn, AL, 36849, USA; Department of Mechanical Engineering, Auburn University, Auburn, AL, 36849, USA
| | - Nabeel Ahmad
- National Center for Additive Manufacturing Excellence (NCAME), Auburn University, Auburn, AL, 36849, USA; Department of Mechanical Engineering, Auburn University, Auburn, AL, 36849, USA
| | - Kayla Corriveau
- National Center for Additive Manufacturing Excellence (NCAME), Auburn University, Auburn, AL, 36849, USA; Department of Clinical Sciences, Auburn University, Auburn, AL, 36849, USA.
| | - Cameron Himel
- Department of Clinical Sciences, Auburn University, Auburn, AL, 36849, USA
| | - Daniel F Silva
- National Center for Additive Manufacturing Excellence (NCAME), Auburn University, Auburn, AL, 36849, USA; Department of Industrial and Systems Engineering, Auburn University, Auburn, AL, 36849, USA
| | - Nima Shamsaei
- National Center for Additive Manufacturing Excellence (NCAME), Auburn University, Auburn, AL, 36849, USA; Department of Mechanical Engineering, Auburn University, Auburn, AL, 36849, USA.
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6
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Paulick L, Knell SC, Smolders LA, Pozzi A, Schmierer PA. Ex vivo comparison of lateral plate repairs of experimental oblique ilial fractures in cats. Vet Surg 2021; 51:191-201. [PMID: 34637153 DOI: 10.1111/vsu.13718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 08/05/2021] [Accepted: 08/22/2021] [Indexed: 11/27/2022]
Abstract
OBJECTIVE To determine the biomechanical behavior of different plate systems used for oblique ilial fracture fixation in cats. STUDY DESIGN Ex vivo biomechanical study. SAMPLE POPULATION Fifty fresh-frozen feline hemipelvises. METHODS Standardized simple oblique ilial fractures were created and fixed via lateral plating, using different implant systems (10 fractures in each group) The systems were: (1) the Advanced Locking Plate System (ALPS-5); (2) the Advanced Locking Plate System (ALPS-6.5); (3) the Locking Compression Plate 2.0 (LCP); (4) the FIXIN 1.9-2.5 Series (FIXIN), and (5) the Dynamic Compression Plate 2.0 (DCP). Stepwise sinusoidal cyclic loading was applied until failure (10-mm displacement). The groups were compared with regard to construct stiffness and the number of cycles withstood before 1-, 2-, 5-, and 10-mm displacement. RESULTS Bending stiffness was lower in ALPS-5 than in other specimens (P < .05). The ALPS-6.5 specimens withstood more cycles (P < .05) before 2-, 5-, and 10-mm displacement than the ALPS-5 and DCP specimens . The LCP and FIXIN specimens endured more cycles than DCP specimens before displaying 5- and 10-mm displacement (P < .05). The ALPS-6.5, FIXIN, and LCP specimens endured higher loads before failure than the DCP specimens (P < .05). Screw loosening occurred in all nonlocking specimens, and bone slicing occurred in all locking specimens. CONCLUSION The DCP and ALPS-5 constructs are less resistant to cyclic loading. Failure in nonlocking specimens involved screw loosening. It involved bone slicing in locking specimens. CLINICAL SIGNIFICANCE Both the plate size and the plate-screw interface are key to lateral plating success in cases of feline ilial fractures. The use of locking plates reduces the risk of the screw loosening in such cases.
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Affiliation(s)
| | - Sebastian C Knell
- Clinic for Small Animal Surgery, Vetsuisse Faculty Zurich, Switzerland
| | - Lucas A Smolders
- Clinic for Small Animal Surgery, Vetsuisse Faculty Zurich, Switzerland
| | - Antonio Pozzi
- Clinic for Small Animal Surgery, Vetsuisse Faculty Zurich, Switzerland
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7
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Brioschi V, Arthurs GI. Cranial cruciate ligament rupture in small dogs (<15 kg): a narrative literature review. J Small Anim Pract 2021; 62:1037-1050. [PMID: 34269419 DOI: 10.1111/jsap.13404] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/06/2021] [Accepted: 06/19/2021] [Indexed: 11/30/2022]
Abstract
Small breed dogs (<15 kg) affected by cranial cruciate ligament rupture secondary to cranial cruciate ligament disease are usually middle-aged (mean age at presentation: 5.4 to 9.8 years); terrier breeds, miniature and toy poodles are over-represented. Small breed dogs have a different morphology of the proximal tibia compared to medium and large breed dogs with a steep tibial plateau angle (mean tibial plateau angle 28.8° to 36.3°), absent base of the flare of the tibial tuberosity and a caudally bowed fibula. There is a lack of evidence regarding the optimal management of cranial cruciate ligament rupture in small dogs. The treatment options consist of conservative management, extracapsular stabilisation, cranial closing wedge ostectomy, tibial plateau levelling osteotomy and tibial tuberosity advancement. The limited evidence available shows that conservative management is likely to result in prolonged recovery time (average time to recovery approximately 4 months). There is paucity of reports focussing on extracapsular stabilisation in small breed dogs, and questions have been raised regarding the early failure of the extracapsular suture subject to higher loads due to the steep tibial plateau angle of small breed dogs. Cranial closing wedge ostectomy and tibial plateau levelling osteotomy have been reported to have low major complication rates and good subjective outcomes. It is controversial whether tibial tuberosity advancement is a suitable technique in dogs with steep tibial plateau angle, which includes most small breed dogs.
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Affiliation(s)
- V Brioschi
- Arthurs Orthopaedics, Northampton, NN12 6JW, UK
| | - G I Arthurs
- Arthurs Orthopaedics, Northampton, NN12 6JW, UK
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8
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Hyndman P, Worth AJ, Clark K. The effect of pearl spacing on single-cycle load-to-failure and cyclic loading parameters of 2.0 mm pearl locking plates. N Z Vet J 2021; 69:337-342. [PMID: 34085907 DOI: 10.1080/00480169.2021.1939189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
AIMS To compare the mechanical performance and mode of failure in four-point bending of two different 2.0 mm "string of pearls" locking plates that differ in dimensions. METHODS Ten *2.0 mm, 82 mm long, 10-hole (Plate A) and ten 2.0 mm, 69 mm long, 12-hole (Plate B) Cortical Pearl Systems were secured to plate extenders and centred beneath an Instron tensile tester in four-point bending. In all constructs, a simulated fracture gap was maintained at 33 mm. Due to differences in plate dimensions, 33 mm corresponded to four pearls (Plate A) and six pearls (Plate B). Following an initial preload of 10 N, ramped single-cycle load-to-failure at 0.1 mm/second was performed in five Plate A and five Plate B constructs. Load and displacement were recorded. Constant frequency sinusoidal cyclic loading (33 N) at 20 mm/minute was performed on five Plate A and five Plate B constructs following 10 N of preload. Maximum moment and cycle count were recorded. Testing and data analysis were completed in accordance with the American Society for Testing and Materials F382-14 guidelines. Differences in performance and mode of failure were compared. RESULTS : Plate A constructs produced higher mean values for bending stiffness (19.8 (SD 2.0) N/mm vs. 10.1 (SD 0.6) N/mm; p < 0.001), bending structural stiffness (0.77 (SD 0.08) Nm2 vs. 0.39 (SD 0.02) Nm2; p < 0.001), yield point (64.1 (SD 4.2) N vs. 54.6 (SD 3.9) N; p = 0.01), proof load (65.4 (SD 3.2) N vs. 55.6 (SD 4.0) N; p = 0.005), and bending strength (1.3 (SD 0.1) Nm vs. 1.1 (SD 0.08) Nm; p = 0.005) when compared to Plate B constructs in single cycle load-to-failure. Plate A constructs had a greater (p = 0.001) mean cycle count to failure (26,178 (SD 4,061) cycles) when compared with Plate B constructs (15,550 (SD 1,291) cycles). All plates failed by non-catastrophic plastic deformation. CONCLUSIONS Plate A, which is wider, thicker and has a greater spacing between pearls, was mechanically superior to Plate B in four-point bending under single-cycle load-to-failure and sinusoidal cyclic loading. CLINICAL RELEVANCE Although mechanical differences were identified in four-point bending, in vivo biomechanical performance remains undetermined. By selecting Plate B, the clinician may gain bone purchase through a greater number of pearls and thus screws per unit length, however, the inferior mechanical characteristics, as evaluated in four-point bending, should also be considered. Further research into the mechanical and biomechanical performance of these plating systems is warranted.
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Affiliation(s)
- P Hyndman
- School of Veterinary Science, Massey University, Palmerston North, New Zealand
| | - A J Worth
- School of Veterinary Science, Massey University, Palmerston North, New Zealand
| | - K Clark
- School of Veterinary Science, Massey University, Palmerston North, New Zealand
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Jung HJ, Jang A, Yim HJ, Han CH, Lee JH. Effect of Screw Insertion Torque on Mechanical Properties of a Hybrid Polyaxial Locking System. Vet Comp Orthop Traumatol 2020; 34:17-23. [PMID: 33065748 DOI: 10.1055/s-0040-1716679] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
OBJECTIVE The aim of this study was to determine the effect of insertion torque and angulation on the push-out strength of screws in Atraumatic Rigid Fixation (ARIX) system. MATERIALS AND METHODS In vitro mechanical tests of the ARIX system were conducted. Screw plate constructs (n = 120) were tested using five different insertion torques at four different angles relative to the perpendicular axis of the plate. Before the push-out test, screws were locked into the plates, and the push-out force of the screw was measured by applying a load parallel to the screw axis. RESULTS Implant failure was observed at 0.8 Nm at an insertion angle of 15 degrees, and at 1 Nm at 0 degree, 5 degrees and 10 degrees. Two types of failures were observed: cold welding and plate deformation. An insertion torque of 0.8 Nm produced a significantly higher push-out force compared with 0.2 Nm. Non-angled specimens with 0.8 Nm insertion torque exhibited significantly higher screw push-out forces compared with other tested specimens and insertion angles. Insertion angle did not affect screw push-out force at insertion torques of 0, 0.2, 0.4 and 0.6 Nm. CONCLUSION The ARIX locking system is much more sensitive to insertion torque than angle. An effect of insertion angle was observed only at an insertion torque of 0.8 Nm, under which all angles significantly decreased push-out force relative to zero degrees of angulation. In addition, low insertion torques can result in screws loosening over time, while greater insertion torques than 1 Nm can result in screw head stripping and plate hole deformation.
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Affiliation(s)
- Hye-Jin Jung
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju-Si, South Korea
| | - Aram Jang
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju-Si, South Korea
| | - Hyeong-Jun Yim
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju-Si, South Korea
| | - Chang-Hoon Han
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju-Si, South Korea
| | - Jae-Hoon Lee
- Institute of Animal Medicine, College of Veterinary Medicine, Gyeongsang National University, Jinju-Si, South Korea
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Kaczmarek J, Bartkowiak T, Paczos P, Gapinski B, Jader H, Unger M. How Do the Locking Screws Lock? A Micro-CT Study of 3.5-mm Locking Screw Mechanism. Vet Comp Orthop Traumatol 2020; 33:316-326. [PMID: 32590864 DOI: 10.1055/s-0040-1709728] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To quantify the amount of the screw head thread and the plate hole thread connection in two 3.5 mm locking plates: Locking Compression Plate (LCP) and Polyaxial Locking System (PLS). MATERIALS AND METHODS A micro - CT scan of a screw head - plate hole connection was performed pre- and post destructive tests. Tests were performed on bone surrogates in a fracture gap model. The 3.5 LCP and 3.5 PLS plates, with 3 perpendicular screws per segment were used in a destructive static test. The 3.5 PLS plates with mono- and polyaxial screws were compared in a cyclic fatigue tests in two orthogonal directions. Pre - and post - test scan datasets were compared. Each dataset was converted into serial images depicting sections cut orthogonally to locking screw axis. The amount of engagement was detected through automated image postprocessing. RESULTS The mean amount of the thread connection for the LCP was 28.85% before and 18.55% after destructive static test. The mean amount of the connection for the PLS was 16.20% before and 14.55% after destructive static test. When inserted monoaxially, the mean amount of the connection for the PLS screws was 14.4% before and 19.24% after destructive cyclic test. The mean amount of the connection for the polyaxial inserted PLS screws when loaded against plate thickness was 2.99% before and 2.08% after destructive cyclic test. The mean amount of the connection for the polyaxial inserted PLS screws when loaded against plate width was 3.36% before and 3.93% after destructive cyclic test. The 3D visualization of the thread connection showed that the initial interface points between screw head and plate hole are different for both LCP and PLS after the destructive testing. Depending on the type of applied force, there was either loss or increase of the contact. CLINICAL RELEVANCE Micro-CT offers news possibilities in locking implant investigation. It might be helpful in better understanding the nature of locking mechanism and prediction of possible mode of failure in different systems.
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Affiliation(s)
| | | | | | | | - Hanna Jader
- Poznan University of Technology, Poznan, Poland
| | - Martin Unger
- AniCura Kleintierspezialisten Augsburg, Augsburg, Germany
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11
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Marturello DM, Wei F, Déjardin LM. Characterization of the torsional structural properties of feline femurs and surrogate bone models for mechanical testing of orthopedic implants. Vet Surg 2018; 48:229-236. [DOI: 10.1111/vsu.13136] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 08/27/2018] [Accepted: 10/22/2018] [Indexed: 12/01/2022]
Affiliation(s)
- Danielle M. Marturello
- Department of Small Animal Clinical SciencesMichigan State University East Lansing Michigan
| | - Feng Wei
- Orthopaedic Biomechanics LaboratoriesCollege of Osteopathic Medicine, Michigan State University East Lansing Michigan
| | - Loïc M. Déjardin
- Department of Small Animal Clinical SciencesMichigan State University East Lansing Michigan
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12
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Field MR, Butler R, Wills RW, Maxwell WM. Retrospective evaluation of perioperative and short term clinical outcomes in appendicular long bone skeleton fractures repaired via the string of pearls (SOP) locking plate system. BMC Vet Res 2018; 14:386. [PMID: 30518361 PMCID: PMC6282292 DOI: 10.1186/s12917-018-1707-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2018] [Accepted: 11/21/2018] [Indexed: 11/28/2022] Open
Abstract
BACKGROUND Internal plate fixation and, more recently, locking plate fixation are commonly used in the repair of fractures in small animal surgery. This retrospective study reviewed the use of the String of Pearls locking plate system in the fixation/repair of appendicular long bone skeleton fractures in 31 small animal veterinary patients (33 fractures). RESULTS Major complications necessitating revision surgery occurred in 7/33 (21%), with implant failure as the inciting cause in all cases. Variables corresponding to an unsuccessful outcome were evaluated, and a correlation was found with plates placed in a bridging manner (placed without rigid anatomic reconstruction, p = 0.02) and length of follow-up (p = 0.01). CONCLUSIONS The SOP plating system can be used in the repair of appendicular longbone skeletal fractures, however, the authors propose that adjunct fixation, such as intramedullary pin, double plating, or external coaptation would likely improve results and should be considered imperative in cases in which anatomic reconstruction is either not desirable or achievable.
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Affiliation(s)
- Matthew R. Field
- Arkansas Veterinary Emergency & Specialists, 11619 Pleasant Ridge Road, Little Rock, AR 72212 USA
| | - Ryan Butler
- Mississippi State University, College of Veterinary Medicine, 240 Wise Center Drive, Starkville, MS 39762 USA
| | - Robert W. Wills
- Mississippi State University, College of Veterinary Medicine, 240 Wise Center Drive, Starkville, MS 39762 USA
| | - Wilburn M. Maxwell
- Memphis Veterinary Specialists, 555 Trinity Creek Cove, Cordova, TN 38018 USA
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13
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Schmierer PA, Smolders LA, Zderic I, Gueorguiev B, Pozzi A, Knell SC. Biomechanical properties of plate constructs for feline ilial fracture gap stabilization. Vet Surg 2018; 48:88-95. [DOI: 10.1111/vsu.13124] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 07/03/2018] [Accepted: 08/10/2018] [Indexed: 11/29/2022]
Affiliation(s)
- Philipp A. Schmierer
- Clinic for Small Animal Surgery; Vetsuisse Faculty University of Zurich; Zurich Switzerland
| | - Lucas A. Smolders
- Clinic for Small Animal Surgery; Vetsuisse Faculty University of Zurich; Zurich Switzerland
| | - Ivan Zderic
- AO Research Institute Davos; Davos Switzerland
| | | | - Antonio Pozzi
- Clinic for Small Animal Surgery; Vetsuisse Faculty University of Zurich; Zurich Switzerland
| | - Sebastian C. Knell
- Clinic for Small Animal Surgery; Vetsuisse Faculty University of Zurich; Zurich Switzerland
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14
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Comparison of double locking plate constructs with single non-locking plate constructs in single cycle to failure in bending and torsion. Vet Comp Orthop Traumatol 2017; 28:234-9. [DOI: 10.3415/vcot-14-09-0149] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 04/23/2015] [Indexed: 11/17/2022]
Abstract
SummaryObjective: To evaluate the biomechanical properties of single 3.5 mm broad dynamic compression plate (DCP) and double 3.5 mm String-of-Pearls (SOP) plate constructs in single-cycle bending and torsion. We hypothesized that the double SOP construct would outperform the broad DCP in both bending and torsional testing.Methods: Broad DCP plates and double 3.5 mm SOP plates were secured to a previously validated bone model in an effort to simulate bridging osteosynthesis. Constructs were tested in both four-point bending and torsional testing.Results: The double SOP constructs had significantly greater bending stiffness, bending strength, bending structural stiffness, and torsional stiffness when compared to the broad DCP constructs. The single broad DCP constructs had significantly higher yield torque and yield angles during torsional testing.Clinical relevance: Although the in vitro mechanical performance of the double SOP construct was significantly greater than the single broad DCP constructs under bending loads, the actual differences were small. Various patient, fracture, and implant factors must be considered when choosing an appropriate implant for fracture fixation.
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Padron AA, Owen JR, Wayne JS, Aktay SA, Barnes RF. In vitro biomechanical testing of the 3.5 mm LCP in torsion: a comparison of unicortical locking to bicortical nonlocking screws placed nearest the fracture gap. BMC Res Notes 2017; 10:768. [PMID: 29282136 PMCID: PMC5745636 DOI: 10.1186/s13104-017-3102-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 12/16/2017] [Indexed: 11/15/2022] Open
Abstract
Objective This biomechanical study compared the torsional strength and stiffness of a locking compression plate with all locking versus nonlocking screws and examined the effect of placing a locking unicortical or nonlocking bicortical screw nearest the fracture gap in a synthetic bone model. Results Synthetic bone models simulating a diaphyseal fracture without anatomic reduction were tested using four screw configurations: all bicortical locking (ABL), all bicortical nonlocking (ABN), a hybrid construct with a bicortical nonlocking screw nearest the fracture gap (BN), and a unicortical locking screw placed nearest the fracture gap (UL). Torsional stiffness, rotation and torque at failure were compared via ANOVA and post hoc pairwise comparisons (p < 0.05). ABN and BN had the highest stiffness (p < 0.01) with ABL greater than UL (p < 0.01). Rotation at failure was greatest for ABL (p < 0.01) with UL greater than ABN (p < 0.05). Unicortical locking screws nearest the fracture gap decreased stiffness, without significantly affecting torque or rotation at failure. Construct stiffness was found to exist in a very narrow range of 0.9–1.2 N m/deg with standard deviations of 0.1 N m/deg in all cases. The results of this study support the use of nonlocking screws in a hybrid construct to increase torsional stiffness. Electronic supplementary material The online version of this article (10.1186/s13104-017-3102-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Alex A Padron
- Virginia Veterinary Surgical Associates a BluePearl® Partner, 5918 W. Broad Street, Richmond, VA, 23230, USA.
| | - John R Owen
- Departments of Orthopaedic Surgery and Biomedical Engineering, Orthopaedic Research Laboratory, 325 McGuire Annex 1112 E. Clay Street, Virginia Commonwealth University, Richmond, VA, 23298-0694, USA
| | - Jennifer S Wayne
- Departments of Orthopaedic Surgery and Biomedical Engineering, Orthopaedic Research Laboratory, 325 McGuire Annex 1112 E. Clay Street, Virginia Commonwealth University, Richmond, VA, 23298-0694, USA
| | - Sevima A Aktay
- Virginia Veterinary Surgical Associates a BluePearl® Partner, 5918 W. Broad Street, Richmond, VA, 23230, USA
| | - Roy F Barnes
- Virginia Veterinary Surgical Associates a BluePearl® Partner, 5918 W. Broad Street, Richmond, VA, 23230, USA
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Experiences using the Fixin locking plate system for the stabilization of appendicular fractures in dogs. Vet Comp Orthop Traumatol 2017; 26:61-8. [DOI: 10.3415/vcot-11-11-0154] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 08/22/2012] [Indexed: 11/17/2022]
Abstract
SummaryObjectives: To retrospectively evaluate the stabilization of appendicular fractures in dogs using the Fixin locking plate system.Materials and methods: Medical records and radiographs of dogs with fractures stabilized with the Fixin system in the period from May 2005 to September 2010 were reviewed. For each patient, data pertaining to signalment, the nature of the fracture, implants used, and evidence of fracture healing were recorded. The outcome and complications were determined from clinical and radiographic follow-up examinations. Limb function was evaluated between 40 days and 90 days postoperatively. Owners of pets with complications were contacted by phone for long-term follow-up.Results: Eighty-two fractures in seventy-five dogs met the inclusion criteria for the study. Radiographic re-examinations were carried out between eight days to two years (median 60 days) following surgery. Seventy-three out of 82 fractures (89%) reached union without complications. Major complications were seen in six dogs (7%). Limb function was graded as ‘normal’ in 73/75 (97%) dogs and ‘mild lameness’ in 2/75 (3%) cases.Clinical significance: Despite a modest complication rate, the Fixin locking bone plating system appears to be an acceptable choice of implant for the stabilization of appendicular fractures in dogs.
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Single cycle to failure in bending of three standard and five locking plates and plate constructs. Vet Comp Orthop Traumatol 2017; 24:408-17. [DOI: 10.3415/vcot-11-04-0061] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2011] [Accepted: 07/29/2011] [Indexed: 11/17/2022]
Abstract
SummaryObjective: To evaluate the biomechanical properties of standard and locking plates in bending. We hypothesised that titanium (Ti) constructs would have the greatest deformation and that String of Pearl (SOP) constructs would have the greatest strength and stiffness, and would behave differently compared to plates alone.Methods: Dynamic compression plates (DCP), stainless steel (SS) limited contact (LC)-DCP®, Ti LC-DCP, locking compression plates (LCP), 10 mm and 11 mm advanced locking plate system (ALPS 10 / 11), SOP and Fixin plates were evaluated individually and as constructs applied to a validated bone model simulating a bridging osteosynthesis. Bending stiffness and strength were compared using one-way ANOVA with post hoc Tukey, and un-paired t-test (p <0.05).Results: The SOP plates had significantly greater stiffness than all other plates Ti LCDCP, ALPS 10 and Fixin plates had significantly lower stiffness than all other plates. The SOP constructs had the highest mean bending stiffness, and strength that was significantly different from only the Ti LC-DCP, ALPS 10 and Fixin constructs. The ALPS 10 constructs had the lowest mean bending stiffness, and strength that was significantly different from only ALPS 11 and SOP constructs. Comparison of bending structural stiffness of plates versus constructs showed a significant difference in all plate pairs except for the DCP and ALPS 10.Clinical relevance: Due to differing plate construct properties inherent to these diverse implant systems, identical approaches to fracture management and plate application cannot be applied.Presented at the 38th Annual Conference of the Veterinary Orthopedic Society, Snowmass, CO, USA March 6, 2011 (Mark S. Bloomberg Memorial Research Award recipient).
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Guthrie JW, Kalff S. Tibial plateau levelling osteotomy locking-compression plates for stabilisation of canine and feline ilial body fractures. J Small Anim Pract 2017; 59:232-237. [DOI: 10.1111/jsap.12803] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 11/10/2017] [Accepted: 11/13/2017] [Indexed: 11/30/2022]
Affiliation(s)
| | - S. Kalff
- Fitzpatrick Referrals; Eashing Surrey, GU7 2QQ UK
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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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Barnes DC, Trinterud T, Owen MR, Bush MA. Short-term outcome and complications of TPLO using anatomically contoured locking compression plates in small/medium-breed dogs with "excessive" tibial plateau angle. J Small Anim Pract 2016; 57:305-10. [PMID: 27148864 DOI: 10.1111/jsap.12486] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Revised: 01/18/2016] [Accepted: 02/11/2016] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To report short-term radiographic and clinical outcome and complications following tibial plateau levelling osteotomy for the treatment of cranial cruciate ligament insufficiency in dogs less than 18·1 kg with tibial plateau angle greater than 35° using anatomically contoured six-hole locking compression plates. METHODS Retrospective data were collected on: preoperative, postoperative and follow-up tibial plateau angles, plateau segment rotation, tibial tuberosity width and length of the cranial aspect of tibial tuberosity segment from the patellar tendon insertion and rotation of the tibial plateau below the level of the insertion of the patellar ligament. RESULTS In 26 small dogs (29 stifles in total), mean preoperative, postoperative and follow-up tibial plateau angles were 38·2°, 4·8°, and 4·4°, respectively. Documented postoperative complications were limited to patellar tendinopathy in a single case (3·4%) and tibial tuberosity or fibula fracture were not observed. CLINICAL SIGNIFICANCE Short-term radiographic and clinical outcome of tibial plateau levelling osteotomy stabilised with anatomically contoured six-hole locking compression plates for the treatment of small dogs with large tibial plateau angle suggests a very low risk of complications. Rotation beyond the "safe point" is necessary to perform full rotation in some cases, but does not appear to incur an increased risk of tibial tuberosity fracture.
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Affiliation(s)
- D C Barnes
- Dick White Referrals, Station Farm, London Road, Six-Mile-Bottom, Cambridgeshire, CB8 0UH
| | - T Trinterud
- Dick White Referrals, Station Farm, London Road, Six-Mile-Bottom, Cambridgeshire, CB8 0UH
| | - M R Owen
- Dick White Referrals, Station Farm, London Road, Six-Mile-Bottom, Cambridgeshire, CB8 0UH
| | - M A Bush
- Dick White Referrals, Station Farm, London Road, Six-Mile-Bottom, Cambridgeshire, CB8 0UH
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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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Schmierer PA, Kircher PR, Hartnack S, Knell SC. Screw Loosening and Pelvic Canal Narrowing After Lateral Plating of Feline Ilial Fractures With Locking and Nonlocking Plates. Vet Surg 2015; 44:900-4. [DOI: 10.1111/vsu.12367] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Philipp A. Schmierer
- Clinic for Small Animal Surgery; Vetsuisse Faculty University of Zurich; Zurich Switzerland
| | - Patrick R. Kircher
- Division of Diagnostic Imaging; Vetsuisse Faculty University of Zurich; Zurich Switzerland
| | - Sonja Hartnack
- Division of Epidemiology; Vetsuisse Faculty University of Zurich; Zurich Switzerland
| | - Sebastian C. Knell
- Clinic for Small Animal Surgery; Vetsuisse Faculty University of Zurich; Zurich Switzerland
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Biomechanical comparison of two locking plate constructs under cyclic torsional loading in a fracture gap model. Two screws versus three screws per fragment. Vet Comp Orthop Traumatol 2015. [PMID: 26219753 DOI: 10.3415/vcot-14-12-0181] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVES The number of locking screws required per fragment during bridging osteosynthesis 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.
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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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Demianiuk RM, Benamou J, Rutherford S, Beckett C, Ness MG, Déjardin LM. Effect of screw type and distribution on the torsional stability of 3.5 mm string of pearls locking plate constructs. Vet Surg 2014; 44:119-25. [PMID: 25231907 DOI: 10.1111/j.1532-950x.2014.12273.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Accepted: 06/01/2014] [Indexed: 11/28/2022]
Abstract
OBJECTIVE To evaluate the effects of screw type (mono- [M] versus bicortical [B]), number, and position on torsional stability of String of Pearls (SOP) locking plate constructs. STUDY DESIGN In vitro mechanical study. METHODS SOP plates (n = 32) were applied to bone models and divided into 8 groups named according to screw type (M or B) and position in each fragment relative to the fracture gap starting at the outermost plate hole. Positive and negative controls were MMM and BBB, respectively. Specimens were non-destructively tested in torsion. Compliance and angular deformation were statistically compared (P < .002). RESULTS The MMM construct was most compliant (P < .001). Compliance decreased in groups with a single bicortical screw (P < .001). Compared to the MMM group, torsional compliance decreased in constructs where a single monocortical screw was replaced with a bicortical screw (P < .001). Compared with a centrally positioned bicortical screw, constructs with a bicortical screw in either outer- or innermost position were 15% and 23% less compliant, respectively (P < .001). Addition of a second bicortical screw/fragment further decreased compliance (P < .001). No significant difference was found between groups with 2 bicortical screws. The BBB construct was least compliant (P < .001). Group responses for angular deformation followed the same pattern of significance recorded for compliance. CONCLUSIONS A minimum of 1 bicortical screw/fragment should be used to increase torsional stability of 3.5 mm SOP constructs. Positioning this screw at the inner- or outermost positions relative to the fracture is preferred, with the innermost position providing the greatest improvement in stability. Should further torsional stability be desired, increasing the number of bicortical screws is recommended. Clinically, these results may assist with preoperative planning of various fracture patterns.
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Affiliation(s)
- Ryan M Demianiuk
- Collaborative Orthopaedic Investigations Laboratory, Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, Michigan
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Malenfant RC, Sod GA. In VitroBiomechanical 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; 43:465-70. [DOI: 10.1111/j.1532-950x.2014.12095.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2011] [Accepted: 06/03/2012] [Indexed: 11/30/2022]
Affiliation(s)
- Renee-Claire Malenfant
- Department of Veterinary Clinical Science, School of Veterinary Medicine; Louisiana State University; Baton Rouge Louisiana
| | - Gary A. Sod
- Department of Veterinary Clinical Science, School of Veterinary Medicine; Louisiana State University; Baton Rouge Louisiana
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Guerrero TG, Kalchofner K, Scherrer N, Kircher P. The Advanced Locking Plate System (ALPS): A Retrospective Evaluation in 71 Small Animal Patients. Vet Surg 2014; 43:127-35. [DOI: 10.1111/j.1532-950x.2014.12097.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2013] [Accepted: 10/01/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Tomás G. Guerrero
- Department for Small Animal Surgery; Vetsuisse Faculty University of Zurich; Zurich Switzerland
- Small Animal Medicine and Surgery Academic Program; School of Veterinary Medicine; St. George's University; True Blue Grenada West Indies
| | - Karin Kalchofner
- Small Animal Medicine and Surgery Academic Program; School of Veterinary Medicine; St. George's University; True Blue Grenada West Indies
- Section Anesthesiology; Equine Department; Vetsuisse Faculty University of Zurich; Zurich Switzerland
| | - Nicole Scherrer
- Department for Small Animal Surgery; Vetsuisse Faculty University of Zurich; Zurich Switzerland
| | - Patrick Kircher
- Division of Diagnostic Imaging; Vetsuisse Faculty University of Zurich; Zurich Switzerland
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Barnhart MD, Rides CF, Kennedy SC, Aiken SW, Walls CM, Horstman CL, Mason D, Chandler JC, Brourman JD, Murphy SM, Pike F, Naber SJ. Fracture Repair Using a Polyaxial Locking Plate System (PAX). Vet Surg 2012; 42:60-6. [DOI: 10.1111/j.1532-950x.2012.01063.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
| | | | | | | | - Charles M. Walls
- Sage Centers for Veterinary Specialty and Emergency Care; Concord; CA
| | | | - David Mason
- Las Vegas Veterinary Specialty Center; Las Vegas; NV
| | | | | | | | | | - Steven J. Naber
- Department of Statistics; The Ohio State University; Columbus; OH
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Chao P, Lewis DD, Kowaleski MP, Pozzi A. Biomechanical Concepts Applicable to Minimally Invasive Fracture Repair in Small Animals. Vet Clin North Am Small Anim Pract 2012; 42:853-72, v. [DOI: 10.1016/j.cvsm.2012.07.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Dynamics of screw and plate interaction. Vet Comp Orthop Traumatol 2011; 24:III-IV. [PMID: 22089032 DOI: 10.3415/vcot-11-10-0151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2011] [Accepted: 10/25/2011] [Indexed: 11/17/2022]
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