Biomechanical evaluation of high tibial osteotomy plate with internal support block using finite element analysis

Background/Objective High tibial osteotomy (HTO) is a common treatment for medial knee arthrosis. However, a high rate of complications associated with a plate and a significant loss of correction have been reported. Therefore, an internal support block (ISB) is designed to enhance the initial stability of the fixation device that is important for successful bone healing and maintenance of the correction angle of the osteotomy site. The purpose of this study was performed to examine if an internal support block combined with a plate reduces the stress on the plate and screw area. Methods Finite element models were reconstructed following three different implant combinations. Two loading conditions were applied to simulate standing and initial sit-to-stand postures. Data analysis was conducted to evaluate the axial displacement of the posteromedial tibial plateau, which represents the loss of the posteromedial tibial plateau in clinical observation. Moreover, the stresses on the bone plate and locking screws were evaluated. Results Compared to the TomoFix plate, the ISB reduced the axial displacement by 73% and 76% in standing and initial sit-to-stand loading conditions, respectively. The plate with an ISB reduced stress by 90% on the bone plate and by 73% on the locking screw during standing compared to the standalone TomoFix plate. During the initial sit-to-stand loading condition, the ISB reduced the stress by 93% and 77% on the bone plate and the locking screw, respectively. Conclusion The addition of the PEEK block showed a benefit for structural stability in the osteotomy site. However, further clinical trials are necessary to evaluate the clinical benefit of reduced implant stress and the internal support block on the healing of the medial bone tissue.

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Computational comparison of different plating strategies in medial open-wedge high tibial osteotomy with lateral hinge fractures

Journal of Orthopaedic Surgery and Research ◽

10.1186/s13018-020-01922-0 ◽

2020 ◽

Vol 15 (1) ◽

Author(s):

Yen-Nien Chen ◽

Chang-Han Chuang ◽

Tai-Hua Yang ◽

Chih-Wei Chang ◽

Chun-Ting Li ◽

...

Keyword(s):

High Tibial Osteotomy ◽

Peak Stress ◽

Tibial Osteotomy ◽

Wedge High Tibial Osteotomy ◽

Locking Screw ◽

Tomofix Plate ◽

Hinge Fracture ◽

Computational Comparison ◽

Plate Breakage ◽

Mechanical Studies

Abstract Background Lateral hinge fracture (LHF) is associated with nonunion and plate breakage in high tibial osteotomy (HTO). Mechanical studies investigating fixation strategies for LHFs to restore stability and avoid plate breakage are absent. This study used computer simulation to compare mechanical stabilities in HTO for different LHFs fixed with medial and bilateral locking plates. Methods A finite element knee model was created with HTO and three types of LHF, namely T1, T2, and T3 fractures, based on the Takeuchi classification. Either medial plating or bilateral plating was used to fix the HTO with LHFs. Furthermore, the significance of the locking screw at the combi hole (D-hole) of the medial TomoFix plate was evaluated. Results The osteotomy gap shortening distance increased from 0.53 to 0.76, 0.79, and 0.72 mm after T1, T2, and T3 LHFs, respectively, with medial plating only. Bilateral plating could efficiently restore stability and maintain the osteotomy gap. Furthermore, using the D-hole screw reduced the peak stress on the medial plate by 28.7% (from 495 to 353 MPa), 26.6% (from 470 to 345 MPa), and 32.6% (from 454 to 306 MPa) in T1, T2, and T3 LHFs, respectively. Conclusion Bilateral plating is a recommended strategy to restore HTO stability in LHFs. Furthermore, using a D-hole locking screw is strongly recommended to reduce the stress on the medial plate for lowering plate breakage risk.

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Effects of plate contouring quality on the biomechanical performance of high tibial osteotomy fixation: A parametric finite element study

Proceedings of the Institution of Mechanical Engineers Part H Journal of Engineering in Medicine ◽

10.1177/09544119211069207 ◽

2022 ◽

pp. 095441192110692

Author(s):

Zahra Hayatbakhsh ◽

Farzam Farahmand

Keyword(s):

Finite Element ◽

High Tibial Osteotomy ◽

Plate Fixation ◽

Element Model ◽

Von Mises Stress ◽

Osteotomy Site ◽

Tibial Osteotomy ◽

Intimate Contact ◽

Initial Shape ◽

Pull Out

Locking plates have threaded holes, in which threaded-head screws are affixed. Hence, they do not need to be in intimate contact with underlying bone to provide fixation. There are, however, reports that a large distance between the plate and the bone might cause clinical complications such as delayed union or nonunion, screw pull out, and screw and plate breakage. Considering the diversity in the capabilities and costs of different plate customization techniques, the purpose of this study was to investigate the effect of the plate contouring quality on the biomechanical performance of high tibial osteotomy (HTO) fixation. A finite element model of proximal tibia was developed in Abaqus, using the QCT data of a cadaver. The model was then subjected to open-wedge HTO (correction angle 12°) with TomoFix plate fixation. The sagittal curvature of the plate was changed parametrically to provide certain levels of geometrical fit, and the biomechanical performance parameters of fixation were assessed. Results indicated 5%, 9% and 38% increase in the stiffness of the construct, and the von Mises stress in the plate and locking screw just above the osteotomy site, respectively, when the level of fit of plate changed from 0% (initial non-contoured initial shape) to 100% (fully adapted shape). The same change decreased the pressure at the lateral hinge of the osteotomy by 61%, and the mean of the tensile stress on the screw shaft by 12%. It was concluded that the level of fit has conflicting effects on the biomechanical parameters of the HTO fixation system, that is, the structural stiffness, the pressure at the lateral hinge, the stresses in the plate and screws, and the pull out resistance of the screws. In particular, for HTO patients with high quality bone, the optimal level of fit should provide a tradeoff between these parameters.

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The effect of plate design, bridging span, and fracture healing on the performance of high tibial osteotomy plates

Bone and Joint Research ◽

10.1302/2046-3758.712.bjr-2018-0035.r1 ◽

2018 ◽

Vol 7 (12) ◽

pp. 639-649 ◽

Cited By ~ 9

Author(s):

A. R. MacLeod ◽

G. Serrancoli ◽

B. J. Fregly ◽

A. D. Toms ◽

H. S. Gill

Keyword(s):

Finite Element ◽

Fracture Healing ◽

High Tibial Osteotomy ◽

Early Stage ◽

Osteotomy Site ◽

Tibial Osteotomy ◽

Opening Wedge ◽

Industry Standard ◽

Plate Design ◽

Standard Plate

Objectives Opening wedge high tibial osteotomy (HTO) is an established surgical procedure for the treatment of early-stage knee arthritis. Other than infection, the majority of complications are related to mechanical factors – in particular, stimulation of healing at the osteotomy site. This study used finite element (FE) analysis to investigate the effect of plate design and bridging span on interfragmentary movement (IFM) and the influence of fracture healing on plate stress and potential failure. Materials and Methods A 10° opening wedge HTO was created in a composite tibia. Imaging and strain gauge data were used to create and validate FE models. Models of an intact tibia and a tibia implanted with a custom HTO plate using two different bridging spans were validated against experimental data. Physiological muscle forces and different stages of osteotomy gap healing simulating up to six weeks postoperatively were then incorporated. Predictions of plate stress and IFM for the custom plate were compared against predictions for an industry standard plate (TomoFix). Results For both plate types, long spans increased IFM but did not substantially alter peak plate stress. The custom plate increased axial and shear IFM values by up to 24% and 47%, respectively, compared with the TomoFix. In all cases, a callus stiffness of 528 MPa was required to reduce plate stress below the fatigue strength of titanium alloy. Conclusion We demonstrate that larger bridging spans in opening wedge HTO increase IFM without substantially increasing plate stress. The results indicate, however, that callus healing is required to prevent fatigue failure. Cite this article: A. R. MacLeod, G. Serrancoli, B. J. Fregly, A. D. Toms, H. S. Gill. The effect of plate design, bridging span, and fracture healing on the performance of high tibial osteotomy plates: An experimental and finite element study. Bone Joint Res 2018;7:639–649. DOI: 10.1302/2046-3758.712.BJR-2018-0035.R1.

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Finite element analysis of Puddu and Tomofix plate fixation for open wedge high tibial osteotomy

Injury ◽

10.1016/j.injury.2011.12.006 ◽

2012 ◽

Vol 43 (6) ◽

pp. 898-902 ◽

Cited By ~ 68

Author(s):

Raja Mohd Aizat Raja Izaham ◽

Mohammed Rafiq Abdul Kadir ◽

Abdul Halim Abdul Rashid ◽

Md. Golam Hossain ◽

T. Kamarul

Keyword(s):

Finite Element Analysis ◽

Finite Element ◽

High Tibial Osteotomy ◽

Plate Fixation ◽

Tibial Osteotomy ◽

Open Wedge ◽

Element Analysis ◽

Wedge High Tibial Osteotomy ◽

Tomofix Plate

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Assessing the Local Mechanical Environment in Medial Opening Wedge High Tibial Osteotomy Using Finite Element Analysis

Journal of Biomechanical Engineering ◽

10.1115/1.4028966 ◽

2015 ◽

Vol 137 (3) ◽

Cited By ~ 9

Author(s):

Yves Pauchard ◽

Todor G. Ivanov ◽

David D. McErlain ◽

Jaques S. Milner ◽

J. Robert Giffin ◽

...

Keyword(s):

Finite Element ◽

High Tibial Osteotomy ◽

Volume Fraction ◽

Compressive Strain ◽

Tibial Osteotomy ◽

Fe Modeling ◽

Knee Alignment ◽

Mechanical Environment ◽

Significant Difference ◽

Subject Specific

High-tibial osteotomy (HTO) is a surgical technique aimed at shifting load away from one tibiofemoral compartment, in order the reduce pain and progression of osteoarthritis (OA). Various implants have been designed to stabilize the osteotomy and previous studies have been focused on determining primary stability (a global measure) that these designs provide. It has been shown that the local mechanical environment, characterized by bone strains and segment micromotion, is important in understanding healing and these data are not currently available. Finite element (FE) modeling was utilized to assess the local mechanical environment provided by three different fixation plate designs: short plate with spacer, long plate with spacer and long plate without spacer. Image-based FE models of the knee were constructed from healthy individuals (N = 5) with normal knee alignment. An HTO gap was virtually added without changing the knee alignment and HTO implants were inserted. Subsequently, the local mechanical environment, defined by bone compressive strain and wedge micromotion, was assessed. Furthermore, implant stresses were calculated. Values were computed under vertical compression in zero-degree knee extension with loads set at 1 and 2 times the subject-specific body weight (1 BW, 2 BW). All studied HTO implant designs provide an environment for successful healing at 1 BW and 2 BW loading. Implant von Mises stresses (99th percentile) were below 60 MPa in all experiments, below the material yield strength and significantly lower in long spacer plates. Volume fraction of high compressive strain ( > 3000 microstrain) was below 5% in all experiments and no significant difference between implants was detected. Maximum vertical micromotion between bone segments was below 200 μm in all experiments and significantly larger in the implant without a tooth. Differences between plate designs generally became apparent only at 2 BW loading. Results suggest that with compressive loading of 2 BW, long spacer plates experience the lowest implant stresses, and spacer plates (long or short) result in smaller wedge micromotion, potentially beneficial for healing. Values are sensitive to subject bone geometry, highlighting the need for subject-specific modeling. This study demonstrates the benefits of using image-based FE modeling and bone theory to fine-tune HTO implant design.

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