Histological evolution of the regenerate during bone transport: an experimental study in sheep

López-Pliego, Esperanza Macarena; Giráldez‐Sánchez, Miguel Ángel; Mora‐Macías, Juan; Reina-Romo, Esther; Domı́nguez, J.

doi:10.1016/s0020-1383(16)30600-3

Cited by 11 publications

(15 citation statements)

References 51 publications

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“…Tissue deformation due to movements in other directions was avoided by the stiff fixator-system connected to the intact tibia. In osteotomy models previously described [ 1 , 6 , 16 , 18 ], other movements, such as bending and shear, could not be completely prevented. Cyclic external loads and muscle forces act within the osteotomy site and the bridging fixator systems cannot be perfectly rigid.…”

Section: Discussionmentioning

confidence: 99%

“…Low fixator stiffness was identified as one cause of endochondral ossification, and the more oblique tibia loading delayed healing compared to axially loaded radii in DO studies on dogs [ 1 , 24 ]. López-Pliego et al [ 18 ] have indicated that endochondral ossification during distraction osteogenesis has been reported primarily in small animal studies while intramembranous ossification is dominant in large animal models. They explain this result as a function of fixator stiffness as small animal models typically employ flexible monolateral fixators.…”

Section: Discussionmentioning

confidence: 99%

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Intramembranous bone formation after callus distraction is augmented by increasing axial compressive strain

et al. 2018

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The mechanical environment is a primary factor in the success of distraction osteogenesis. It is known that the interfragmentary movement during the distraction and maturation phase effects the callus formation. In addition to cyclic compression, other movements like shear and bending influence the bone formation process as shown in previous callus distraction studies. Reports of cartilage presence and endochondral ossification in the regenerative zone have been associated with a lack of fixation stability and delayed healing. So far the effects of the direction of interfragmentary movements could not be studied separately. By means of a unique lateral callus distraction model, we investigated the effects of small (0.1 mm) and moderate (0.6 mm), purely axial compression on ossification during callus maturation in sheep. A distraction device incorporating a mobile titanium plate was mounted on the tibia. Following lateral callus distraction, electromechanically controlled movements allowed purely axial cyclic compression of the tissue regenerate. Seven weeks post-operatively, the tissue regenerates were investigated using μCT, histology and immunohistochemistry. The larger amplitude significantly increased bone formation (Fractional bone volume: 19.4% vs. 5.2%, p = 0.03; trabecular thickness: 0.1 mm vs. 0.06 mm, p = 0.006; mean spicule height: 2.6 mm vs. 1.1 mm, p = 0.02) however, no endochondral ossification occurred. The elimination of shear movement, unimpaired neovascularization as well as the tensile strain stimuli during the distraction phase suppressing chondrogenic differentiation may all contribute to the absence of cartilage. In clinical application of distraction osteogenesis, moderate axial interfragmentary movement augments intramembranous ossification provided shear strain is minimized.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Intramembranous bone formation after callus distraction is augmented by increasing axial compressive strain

et al. 2018

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“…To ensure that the callus specimen just contained the woven bone, only the animals slaughtered at 36, 37, 51 and 79 days after surgery were selected for this study. Indeed, Lo´pez-Pliego et al 26 confirmed that the number of osteoclasts was very small at the beginning of the consolidation phase and drastically increased around 50 days after surgery. It is well known that osteoblasts appear in the remodelling site after osteoclasts have finished their activity, more precisely after the reversal period has elapsed.…”

Section: Bone Transport: Formation Of Woven Bonementioning

confidence: 93%

“…The calluses from the animals slaughtered earlier (17, 22 and 29 days) were not used, for these animals presented an excessively immature callus still composed mainly of fibrous tissue instead of woven bone. The histological study revealed bone remodelling activity in the callus 26 of variable intensity for the different animals, depending on the time elapsed from surgery. The existence of bone remodelling is undesirable for this study, as it implies the presence of lamellar tissue in the callus, deposited in the formation phase of the remodelling process.…”

Section: Bone Transport: Formation Of Woven Bonementioning

confidence: 99%

Comparison of the volumetric composition of lamellar bone and the woven bone of calluses

Martínez-Reina

García–Rodríguez

Mora‐Macías

et al. 2018

Proc Inst Mech Eng H

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Woven tissue is mainly present in the bone callus, formed very rapidly either after a fracture or in distraction processes. This high formation speed is probably responsible for its disorganized microstructure and this, in turn, for its low stiffness. Nonetheless, the singular volumetric composition of this tissue may also play a key role in its mechanical properties. The volumetric composition of woven tissue extracted from the bone transport callus of sheep was investigated and compared with that of the lamellar tissue extracted from the cortical shell of the same bone. Significant differences were found in the mineral and water contents, but they can be due to the different ages of both tissues, which affects the mineral/water ratio. However, the content in organic phase remains more or less constant throughout the mineralization process and has proven to be a good variable to measure the different composition of both tissues, being that content significantly higher in woven tissue. This may be linked to the abnormally high concentration of osteocytes in this tissue, which is likely a consequence of the more abundant presence of osteoblasts secreting osteoid and burying other osteoblasts, which then differentiate into osteocytes. This would explain the high formation rate of woven tissue, useful to recover the short-term stability of the bone. Nonetheless, the more abundant presence of organic phase prevents the woven tissue from reaching a stiffness similar to that of lamellar tissue in the long term, when it is fully mineralized.

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“…The porosity was not accounted for, and the mechanical properties were considered to be constant over time according to the literature. The soft callus tissue region was assumed to be mainly granular tissue and was assigned an elastic modulus of 2 MPa and Poisson coefficient of 0.13 . The mechanical properties of the cortical bone were considered to be homogeneously distributed ( E = 17 000 MPa, ν = 0.30) as well as those of the medullar tissue (1 MPa, ν = 0.05) and hard callus tissue (1000 MPa, ν = 0.29) …”

Section: Methodsmentioning

confidence: 99%

Comparison of methods for assigning the material properties of the distraction callus in computational models

Mora‐Macías

Giráldez‐Sánchez

López

et al. 2019

Numer Methods Biomed Eng

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In silico models of distraction osteogenesis and fracture healing usually assume constant mechanical properties for the new bone tissue generated. In addition, these models do not always account for the porosity of the woven bone and its evolution. In this study, finite element analyses based on computed tomography (CT) are used to predict the stiffness of the callus until 69 weeks after surgery using 15 CT images obtained at different stages of an experiment on bone transport, technique in which distraction osteogenesis is used to correct bone defects. Three different approaches were used to assign the mechanical properties to the new bone tissue. First, constant mechanical properties of the hard callus tissue and no porosity were assumed. Nevertheless, this approach did not show good correlations. Second, random variations in the elastic modulus and porosity of the woven bone were taken from previous experimental studies. Finally, the elastic properties of each element were assigned depending on gray scale in CT images. The numerically predicted callus stiffness was compared with previous in vivo measurements. It was concluded firstly that assignment depending on gray scale is the method that provides the best results and secondly that the method that considers a random distribution of porosity and elastic modulus of the callus is also suitable to predict the callus stiffness from 15 weeks after surgery. This finding provides a method for assigning the material properties of the distraction callus, which does not require CT images and may contribute to improve current in silico models.

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Histological evolution of the regenerate during bone transport: an experimental study in sheep

Cited by 11 publications

References 51 publications

Intramembranous bone formation after callus distraction is augmented by increasing axial compressive strain

Intramembranous bone formation after callus distraction is augmented by increasing axial compressive strain

Comparison of the volumetric composition of lamellar bone and the woven bone of calluses

Comparison of methods for assigning the material properties of the distraction callus in computational models

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