Comparison of Healing Process in Open Osteotomy Model and Closed Fracture Model

Park, Sang‐Hyun; O’Connor, Kim M.; Sung, Raymond; McKellop, Harry A.; Sarmiento, Augusto

doi:10.1097/00005131-199902000-00008

Cited by 61 publications

(49 citation statements)

References 16 publications

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“…In contrast, an open osteotomy stabilized with an external fixator can lead to a delayed healing due to soft tissue trauma being induced by the surgical approach. 17 However, it has advantages: the osteotomy can be created in a standardized way; external fixators provide better control of the fixation stability, especially under torsion and shear loading (important as both rotational instability and shear movements in particular hamper fracture healing 9,18 ); and an external fixator is fitted to the bone at some distance from the fracture gap, and, therefore, does not compromise the healing process. Previously, a reliable external device allowing the investigation of the influence of different mechanical conditions on fracture healing in mice was lacking.…”

Section: Discussionmentioning

confidence: 99%

Fracture healing in mice under controlled rigid and flexible conditions using an adjustable external fixator

Röntgen

Blakytny

Matthys

et al. 2010

Journal Orthopaedic Research

101

142

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Mice are increasingly used to investigate mechanobiology in fracture healing. The need exists for standardized models allowing for adjustment of the mechanical conditions in the fracture gap. We introduced such a model using rigid and flexible external fixators with considerably different stiffness (axial stiffnesses of 18.1 and 0.82 N/mm, respectively). Both fixators were used to stabilize a 0.5 mm osteotomy gap in the femur of C57BL/6 mice (each n = 8). Three-point bending tests, CT, and histomorphometry demonstrated a different healing pattern after 21 days. Both fixations induced callus formation with a mixture of intramembranous and enchondral ossification. Under flexible conditions, the bending stiffness of the callus was significantly reduced, and a larger but qualitatively inferior callus with a significantly lower fraction of bone but a higher fraction of cartilage and soft tissue was formed. Monitoring of the animal movement and the ground reaction forces demonstrated physiological loading with no significant differences between the groups, suggesting that the differences in healing were not based on a different loading behavior. In summary, flexible external fracture fixation of the mouse femur led to delayed fracture healing in comparison to a more rigid situation.

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Section: Discussionmentioning

confidence: 99%

Fracture healing in mice under controlled rigid and flexible conditions using an adjustable external fixator

Röntgen

Blakytny

Matthys

et al. 2010

Journal Orthopaedic Research

101

142

View full text Add to dashboard Cite

show abstract

“…In a rabbit tibial fracture model, oblique fractures with a sliding fixator developed more callus and had a larger torsional rigidity than transverse fractures with an axial motion fixator [26]. However, it is difficult to determine if the outcome is due to the difference in strain magnitude or type (axiahhear).…”

Section: Discussionmentioning

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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“…On the other hand, a contributory factor may be the use of the intramedullary stabilisation technique. The development of delayed healing after tibial osteotomy in direct comparison to the closed fracture technique was previously documented in a rabbit model by Park et al [11] using an external fixator for stabilization of the bone defect. These authors showed respective differences two weeks post bone defect, but these had disappeared at later observation time points.…”

Section: Discussionmentioning

confidence: 87%