Biomechanical Stability of Open-Wedge High Tibial Osteotomy: Comparison of Two Locking Plates

Watanabe, Kota; Kamiya, Tomoaki; Suzuki, Daisuke; Otsubo, Hidenori; Teramoto, Atsushi; Suzuki, Toshiya; Yamashita, Toshihiko

doi:10.4236/ojo.2014.410042

Cited by 12 publications

(15 citation statements)

References 6 publications

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“…Stoffel et al (Stoffel et al 2004 ) also performed axial compression load to failure tests to compare the TomoFix plate to the Puddu plate (rectangular short spacer plate) by using composite bones and also reported a better axial stability for the TomoFix. Watanabe et al (Watanabe et al 2014 ) also performed a comparative study of the TomoFix and the Puddu plates by using cadaveric bones and reported the highest failure load for the TomoFix. None of the previously cited studies included the iBalance and the PEEKPower implants, whereas we did not include the Puddu plate.…”

Section: Resultsmentioning

confidence: 99%

Biomechanical properties of five different currently used implants for open-wedge high tibial osteotomy

et al. 2015

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BackgroundAs several new tibial osteotomy plates recently appeared on the market, the aim of the present study was to compare mechanical static and fatigue strength of three newly designed plates with gold standard plates for the treatment of medial knee joint osteoarthritis.MethodsSixteen fourth-generation tibial bone composites underwent a medial open-wedge high tibial osteotomy (HTO) according to standard techniques, using five TomoFix standard plates, five PEEKPower plates and six iBalance implants. Static compression load to failure and load-controlled cyclic fatigue failure tests were performed. Forces, horizontal and vertical displacements were measured; rotational permanent plastic deformations, maximal displacement ranges in the hysteresis loops of the cyclic loading responses and dynamic stiffness were determined.ResultsStatic compression load to failure tests revealed that all plates showed sufficient stability up to 2400 N without any signs of opposite cortex fracture, which occurred above this load in all constructs at different load levels. During the fatigue failure tests, screw breakage in the iBalance group and opposite cortex fractures in all constructs occurred only under physiological loading conditions (<2400 N). The highest fatigue strength in terms of maximal load and number of cycles performed prior to failure was observed for the ContourLock group followed by the iBalance implants, the TomoFix standard (std) and small stature (sm) plates. The PEEKPower group showed the lowest fatigue strength.ConclusionsAll plates showed sufficient stability under static loading. Compared to the TomoFix and the PEEKPower plates, the ContourLock plate and iBalance implant showed a higher mechanical fatigue strength during cyclic fatigue testing. These data suggest that both mechanical static and fatigue strength increase with a wider proximal T-shaped plate design together with diverging proximal screws as used in the ContourLock plate or a closed-wedge construction as in the iBalance design. Mechanical strength of the bone-implant constructs decreases with a narrow T-shaped proximal end design and converging proximal screws (TomoFix) or a short vertical plate design (PEEKPower Plate). Whenever high mechanical strength is required, a ContourLock or iBalance plate should be selected.

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Section: Resultsmentioning

confidence: 99%

Biomechanical properties of five different currently used implants for open-wedge high tibial osteotomy

et al. 2015

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“…The plate did not lose its shape or weaken when the force was applied to it. Conversely, the lateral cortex of the tibial head had no such support, which caused this discrepancy in displacement between the two sides, as the lateral cortex is the weakest point of a MOWHTO (Maas et al , 2013; Watanabe et al , 2014; Diffo Kaze et al , 2015). Furthermore, the positive values at position LSZ and the negative values at position MSZ indicate a valgus malrotation of the tibial head.…”

Section: Discussionmentioning

confidence: 99%

“…This large difference within the synthetic and allograft groups between the two opposite cortices of the tibial head is likely to be due to the volume of the graft being much larger medially than laterally, in order to fit the shape of the osteotomy wedge. The synthetic group showed the highest stiffness medially but the lowest stiffness laterally, suggesting that this type of graft offers the least support to the lateral cortex, the weakest point of a MOWHTO (Maas et al , 2013; Watanabe et al , 2014; Diffo Kaze et al , 2015). This is further supported by the observed breaking up of the synthetic grafts at the lateral side during compression.…”

Section: Discussionmentioning

confidence: 99%

Graft materials provide greater static strength to medial opening wedge high tibial osteotomy than when no graft is included

et al. 2019

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Background The purpose of this study was to compare the stability of medial opening-wedge high tibial osteotomy (MOWHTO) with and without different graft materials. Good clinical and radiological outcomes have been demonstrated when either using or not using graft materials during MOWHTO. Variations in the biomechanical properties of different graft types, regarding the stability they provide a MOWHTO, have not been previously investigated. Methods A 10 mm biplanar MOWHTO was performed on 15 artificial sawbone tibiae, which were fixed using the Activmotion 2 plate. Five bones had OSferion60 wedges (synthetic group), five had allograft bone wedges (allograft group), and five had no wedges (control group) inserted into the osteotomy gap. Static compression was applied axially to each specimen until failure of the osteotomy. Ultimate load, horizontal and vertical displacements were measured and used to calculate construct stiffness and valgus malrotation of the tibial head. Results The synthetic group failed at 6.3 kN, followed by the allograft group (6 kN), and the control group (4.5 kN). The most valgus malrotation of the tibial head was observed in the allograft group (2.6°). The synthetic group showed the highest stiffness at the medial side of the tibial head (9.54 kN·mm − 1 ), but the lowest stiffness at the lateral side (1.59 kN·mm -1) . The allograft group showed high stiffness on the medial side of the tibial head (7.54 kN·mm − 1 ) as well as the highest stiffness on the lateral side (2.18 kN·mm − 1 ). Conclusions The use of graft materials in MOWHTO results in superior material properties compared to the use of no graft. The static strength of MOWHTO is highest when synthetic grafts are inserted into the osteotomy gap. Allograft wedges provide higher mechanical strength to a MOWHTO than when no graft used. In comparison to the synthetic grafts, allograft wedges result in the stiffness of the osteotomy being more similar at the medial and lateral cortices.

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“…The allograft group withstood higher forces than the control group prior to construct failure, which may be explained by the added medial and lateral stiffness of the tibial head provided by the wedge (Fig 8). This added static stiffness may have reduced valgus malrotation of the tibial head, which likely helped to distribute the vertical force more evenly across the tibial head and lowered the stress on the lateral cortex, the weakest point of a MOWHTO [5, 21, 23]. Furthermore, a recent study [24] used a 3D finite element model to find that the way that loads are balanced between the medial and lateral compartments of the knee may be key in optimising the clinical outcome of the procedure.…”

Section: Discussionmentioning

confidence: 99%

The biomechanical effects of allograft wedges used for large corrections during medial opening wedge high tibial osteotomy

et al. 2019

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The inclusion of an allograft wedge during medial opening wedge high tibial osteotomy has been shown to lead to satisfactory time-to-union in larger corrections (>10°). Such large corrections are associated with greater incidences of intraoperative hinge fracture and reduced construct stability. The purpose of this study was to investigate the biomechanical stability that an allograft wedge brings to an osteotomy. Ten medium-size fourth generation artificial sawbone tibiae underwent 12 mm biplanar medial opening wedge high tibial osteotomy with a standard Tomofix plate. Five tibiae had an allograft wedge inserted into the osteotomy gap prior to plate fixation (allograft group). The gap in the remaining tibiae was left unfilled (control group). Each group underwent static compression testing and cyclical fatigue testing until failure of the osteotomy. Peak force, valgus malrotation, number of cycles, displacement and stiffness around the tibial head were analysed. Intraoperative hinge fractures occurred in all specimens. Under static compression, the allograft group withstood higher peak forces (6.01 kN) compared with the control group (5.12 kN). Valgus malrotation was lower, and stiffness was higher, in the allograft group. During cyclical fatigue testing, results within the allograft group were more consistent than within the control group. This may indicate more predictable results in large osteotomies with an allograft. Tibial osteotomies with allograft wedges appear beneficial for larger corrections, and in cases of intraoperative hinge fracture, due to the added construct stability they provide, and the consistency of results compared with tibial osteotomies without a graft.

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Biomechanical Stability of Open-Wedge High Tibial Osteotomy: Comparison of Two Locking Plates

Cited by 12 publications

References 6 publications

Biomechanical properties of five different currently used implants for open-wedge high tibial osteotomy

Biomechanical properties of five different currently used implants for open-wedge high tibial osteotomy

Graft materials provide greater static strength to medial opening wedge high tibial osteotomy than when no graft is included

The biomechanical effects of allograft wedges used for large corrections during medial opening wedge high tibial osteotomy

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