Effect of Instability on Experimental Fracture Healing

Mølster, Anders; Gjerdet, Nils Roar; Raugstad, Tor Steinar; Hvidsten, Kyle; Alho, A; Bang, Gisle

doi:10.3109/17453678208992251

Cited by 45 publications

(26 citation statements)

References 12 publications

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“…Several studies performed using models of rabbit osteotomized femur or rat osteotomized tibia with intramedullary rods for fixation have also reported that rigid fixation induces formation of a smaller callus [16,25]. Although these differences in the fracture healing process have been verified in clinical practice and experiments on large animals, the exact distribution of bone-marrow-derived cells in the fracture callus with a plate in a stable environment has not been elucidated.…”

Section: Discussionmentioning

confidence: 99%

Distribution of Bone Marrow-Derived Cells in the Fracture Callus during Plate Fixation in a Green Fluorescent Protein-Chimeric Mouse Model

et al. 2011

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Abstract:To clarify the distribution of bone-marrow-derived cells in fractures treated by plate fixation, fracture models were created using the green fluorescent protein (GFP) chimeric mouse. We observed 2 types of fracture healing processes with different types of callus formation and cellular events by using Mouse Fix™, a device allowing plate fixation on the mouse femur, and differences in the distribution of bone-marrow-derived cells between the 2 types. The GFP chimeric mice were created by bone marrow transplantation. Fractures were created on the left femurs of mice and stabilized with either rigid (Group R) or flexible (Group F) plates to prepare undecalcified fresh-frozen sections. In Group F, a large external callus and a large intramedullary callus were formed mostly by endochondral ossification. The cells that made up the intramedullary callus and callus in the fracture gap were GFP positive, but most cells of the external callus were not. In Group R, bone union was achieved mostly without external callus formation, bone apposition occurred directly in the gap, and a small intramedullary callus was formed. As observed in Group F, this group had GFP-positive cells in the callus within the fracture gap and in the intramedullary calluses. The results of this study provided direct evidence of the distribution of bone-marrow-derived cells in the callus of fractures treated by plate fixation under different stability conditions.

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Section: Discussionmentioning

confidence: 99%

Distribution of Bone Marrow-Derived Cells in the Fracture Callus during Plate Fixation in a Green Fluorescent Protein-Chimeric Mouse Model

et al. 2011

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“…All of these methods are minimally invasive, requiring only a small incision for insertion of the intramedullary pin. Others have used a more invasive osteotomy method, which requires open surgery and disturbs of the musculature and periosteum [ 1 1,17, 22,23]. However, an osteotomy allows for a more controlled positioning and geometry of the bone defect and makes it possible to leave the fibula intact.…”

Section: Introductionmentioning

confidence: 99%

Intact fibula improves fracture healing in a rat tibia osteotomy model

Shefelbine

Augat

Beck

2005

Journal Orthopaedic Research

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Rat tibia fractures are often used in fracture healing studies. Usually the fracture is stabilized with an intramedullary pin, which provides bending stiffness, but little torsional stiffness. The objective of this research was to determine the in vitro torsional rigidity of an osteotomized tibia with and without the fibula, and to determine if this difference influences the healing process in vivo. In vitro eleven rat tibias received an osteotomy, were stabilized with an intramedullary pin, and were tested in internal rotation to determine the torsional rigidity. The fibula was then manually broken and the torsional rigidity measured again. In vivo 18 rats received a tibia1 osteotomy, eight of which had an additional fractured fibula. After three weeks, the rats were sacrificed and the tibias were analyzed. Bone density in the fracture callus was measured with qCT. Bending rigidity and maximum breaking moment were determined in three-point bending. In vitro testing demonstrated that the torsional rigidity with an intact fibula was nearly two times higher than when the fibula was fractured. Though the torsional rigidity was still small in comparison with an intact bone, it resulted in a significantly different healing process in vivo. Rats with intact fibulas had significantly higher bone mineral density, bending rigidity, and maximum breaking moment compared to rats with a fractured fibula. These results indicate that torsional stability considerably affects the healing process. In a fracture model, it is critical to characterize the mechanical environment of the fracture.

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“…ated with callus formation. 18 Furthermore, we assume that the osteotomies gained their stability in the present study by 8 weeks and the reconstruction process was in progress, [19][20][21][22][23] reducing the importance of the amount of external callus (Table I).…”

Section: Discussionmentioning

confidence: 99%

Intramedullary fixation of distal femoral diaphyseal osteotomies with absorbable self-reinforced poly-L-lactide and metallic intramedullary rods assessed by plain radiographs, quantitative computed tomography, and magnetic resonance imaging: An experimental study in rabbits

Viljanen¹,

Kinnunen²,

Bondestam³

et al. 1998

J. Biomed. Mater. Res.

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Osteotomies of distal femoral diaphysis were fixed intramedullary with self-reinforced poly-L-lactide acid (SR-PLLA) rods in 19 and with metallic rods in 34 adult rabbits. The follow-up times were 8, 16, 24, and 48 weeks. Plain radiographs, computed tomography (CT), quantitative computed tomography (QCT), and magnetic resonance imaging (MRI) were used to evaluate the bone changes at two different levels of the osteotomy region. There were no significant differences in cortical bone density compared to the intact in the SR-PLLA fixed femurs at the osteotomy site. In the metallic-fixed femurs, the density values were significantly lower as compared to the contralateral femurs. There was a significant reduction of the cortical bone density values in SR-PLLA fixed femurs compared to the intact control side outside the osteotomy area at 8 (p = 0.01), at 16 (p = 0.0001), and at 24 weeks (p = 0.0003). In the metallic-fixed femurs significant reductions at 8 weeks (p = 0.02), at 16 weeks (p = 0.01), at 24 weeks (p = 0.009), and at 48 weeks (p = 0.002) were found compared with the intact control. MRI depicted well the SR-PLLA cases allowing studies without removal of the implant. On the contrary, abundant disturbing metallic artifacts were detected during investigation of the metallic-fixed femurs. In conclusion, our results indicated that CT is useful to evaluate the quality of reduction and internal fixation. Furthermore, the constant presence of internal metallic fixation seems to eventually cause osteoporosis in the cortical region of the femur. However, this stress protection effect of intramedullary fixation on the femoral diaphysis seems to be avoided by using an absorbable SR-PLLA rod, thus resulting in a better quality of bone when the osteotomies are healed.

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Effect of Instability on Experimental Fracture Healing

Cited by 45 publications

References 12 publications

Distribution of Bone Marrow-Derived Cells in the Fracture Callus during Plate Fixation in a Green Fluorescent Protein-Chimeric Mouse Model

Distribution of Bone Marrow-Derived Cells in the Fracture Callus during Plate Fixation in a Green Fluorescent Protein-Chimeric Mouse Model

Intact fibula improves fracture healing in a rat tibia osteotomy model

Intramedullary fixation of distal femoral diaphyseal osteotomies with absorbable self-reinforced poly-L-lactide and metallic intramedullary rods assessed by plain radiographs, quantitative computed tomography, and magnetic resonance imaging: An experimental study in rabbits

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