Biomechanical and Densitometric Bone Properties After Callus Distraction in Sheep

Reichel, Heiko; Lebek, Susanne; Alter, Christoph; Hein, W.

doi:10.1097/00003086-199812000-00030

Cited by 36 publications

(20 citation statements)

References 20 publications

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“…In our series of 28 lengthenings using DEXA as an aid to determine when to remove the fixator, there were no fractures or deformities in the regenerate zone and only one in an adjacent bone segment resulting in a fracture rate of 3.6%. One animal study examining biomechanical regenerate strength after distraction osteogenesis in sheep suggested a direct correlation with BMD using DEXA [23]. Although several other radiological techniques have been described to assess the regenerate [11,17,31], none are used on a routine basis.…”

Section: Discussionmentioning

confidence: 99%

“…Dual energy xray absorptiometry (DEXA) is a scanning technique used to determine bone mineral density (BMD) and bone mineral content (BMC). One animal study suggests bone mineral density directly correlates to biomechanical strength [23] and DEXA scans have been proposed as useful tools in assessing the regenerate quality during the distraction phase of lengthening in humans [12,13,18,24]. The question of whether or not DEXA could be useful during the consolidation phase still remains.…”

Section: Introductionmentioning

confidence: 99%

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DEXA as a Predictor of Fixator Removal in Distraction Osteogenesis

Saran

Hamdy

2008

Clinical Orthopaedics &Amp; Related Research

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Premature removal of the fixator after a lengthening procedure can result in gradual bending or acute fracture of the regenerate. We reviewed the records of 26 patients who underwent 28 limb lengthenings between 1997 and 2005 to assess the post lengthening regenerate fracture rate and bone healing index when using dual energy xray absorptiometry (DEXA) to aid in deciding on when to remove the fixator. Sixteen male and 10 female patients with an average age at lengthening of 12.3 years underwent an average lengthening of 5.2 cm (range, 3-9.1 cm). Nineteen femurs and nine tibiae were lengthened. Serial monthly DEXA scans were analyzed for bone mineral density. Bone healing indices and post fixator removal complications were assessed. The fixators were removed once the bone mineral density had plateaued to a less than 10% increase and plain radiographs showed no obvious defects precluding fixator removal. There were no regenerate fractures and only one fracture in the proximal segment of the lengthened bone after apparatus removal and the healing index for the series averaged 47 d/cm (range, 20-73 d/cm). Using serial DEXA scans during the consolidation phase of lengthening has a low rate (3.6%) of fractures while maintaining an acceptable bone healing index without excessively increasing fixation time.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

DEXA as a Predictor of Fixator Removal in Distraction Osteogenesis

Saran

Hamdy

2008

Clinical Orthopaedics &Amp; Related Research

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“…Experiments with fast cyclic applications of a bending moment to an osteotomy, leading to a compression on one site and a distraction on the other site of the osteotomy, resulted in significant callus formation on the compression site, whereas on the distraction site only minimal bone formation occurred. 13 In contrast, continuous quasi-static distraction leads to a tissue strain inducing bone formation even if a fast cyclic deformation of the healing area occurs due to the elastic deformation of the fixation system 7,[14][15][16] and the loading of the operated extremity.…”

Section: Discussionmentioning

confidence: 99%

Temporary distraction and compression of a diaphyseal osteotomy accelerates bone healing

Claes

Augat

Schorlemmer

et al. 2008

Journal Orthopaedic Research

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Mechanical strain during callus distraction is known to stimulate osteogenesis. It is unclear whether this stimulus could be used to enhance the healing of a normal fracture without lengthening the bone. This study tested the hypothesis that a slow temporary distraction and compression of a diaphyseal osteotomy accelerates fracture healing. Fourteen sheep underwent a middiaphyseal osteotomy of the right tibia, stabilized by external fixation. An external fixator allowed either a temporary axial distraction (TD group; n ¼ 6) or a constant fixation (C group; n ¼ 8). Distraction began 7 days postoperatively at a rate of 0.5 mm twice per day for 2 days with subsequent shortening of 1.0 mm twice on the third day. The procedure was repeated four times. Fluorochrome labeling was performed postoperatively. After 8 weeks the sheep were sacrificed and healing was evaluated using densitometric, biomechanical, and histological methods. Bending stiffness of the tibiae after 8 weeks was 58% higher in the TD group than in the C group. The volume of the periosteal callus was significantly (p ¼ 0.05) higher in the TD group (3.9 cm 3 ) than in the C group (2.7 cm 3 ). There was 20% more bone in the fracture gap of the TD group than the C group. There was a significantly higher bone formation rate in the TD group than in the C group. This study demonstrated the feasibility of fracture healing stimulation by the temporary application of distraction and compression. ß

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“…Density of the cortical and medullary canal. This was measured by CT performed in 11 patients in this series and was done by quantitative densitometry using Hounsfield units (HU) [1]. The Hounsfield scale includes different values considering the tissue under examination.…”

Section: Methodsmentioning

confidence: 99%

CT evaluation of regenerated osseous segments following bone transport

Iacobellis

Bulzacchi²,

Rioda

2004

J Orthopaed Traumatol

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IntroductionNewly formed bone with distractional osteogenesis after bone transport presents morphological characteristics that are different from the contralateral bone segment. These differences are visible upon radiographic examination, which can show increased diameter of the newly formed bone. The information given by radiography (anteroposterior and lateral view) is not however sufficient for precise definition of the morphological characteristics of the regenerated segment and, consequently, is inadequate for assessment of mechanical quality. With reference to several earlier morphological and quantitative studies of regenerated bone after lengthening [1-3], we chose to examine similar properties (thickness of the cortical wall, sectional area of the newly formed medullary canal, density of the regenerated bone fragment in the cortical and medullary components) of corticalized, regenerated bone in order to assess any possible relationships to clinical utility. O R I G I N A L Abstract A morphological analysis using radiography and computed tomography was performed in a total of 17 bone segments following single or double bone transport in 11 and 3 patients, respectively. All bone transports involved the tibia, with the exception of 2 single bone transports, which were femoral. The following parameters were measured: cortical wall thickness, sectional area of the medullary canal, and density of the cortical bone and medullary canal in Hounsfield units (HU). The regenerated segments showed a cortical thickness and density that were less than the contralateral portion, with an enlargement of the medullary canal and an increase in density due to the presence of cancellous bone in the medullary area. Successive controls showed an increase in thickness and density of the cortical bone and a small reduction in the diameter of the medullary canal and its cancellous bone. The variations in the cortical and the medullary canal appeared to be independent of the length of the regenerated segment. In the 3 tibia treated by double bone transport, the anatomical variations in the distal regenerated portion varied less from normal values than the proximal portion of the same segment. In the 2 femurs examined, enlargement of the regenerated section was smaller with respect to cases involving regeneration of the proximal tibia. These differences are presumably dependent on the fact that in the latter case, a more vascularized segment is produced after osteotomy in spongy bone, with respect to those involving the distal tibia or femur. Double transport is preferable due to the reduced treatment times.

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Biomechanical and Densitometric Bone Properties After Callus Distraction in Sheep

Cited by 36 publications

References 20 publications

DEXA as a Predictor of Fixator Removal in Distraction Osteogenesis

DEXA as a Predictor of Fixator Removal in Distraction Osteogenesis

Temporary distraction and compression of a diaphyseal osteotomy accelerates bone healing

CT evaluation of regenerated osseous segments following bone transport

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