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Results for “Bony Callus”

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PubMed2005

Effect of calcium sulfate-chitosan composite: pellet on bone formation in bone defect.

The purpose of this experiment was to study the effects of chitosan, calcium sulfate, and calcium sulfate-chitosan composite pellet on the osteogenesis of defective tibia in rabbits. Eighty New Zealand white rabbits, each weighing approximately 3 to 3.5 kg, were used for this study. A 1-cm ostectomy was made on the middle of the tibia of each rabbit with the periosteum preserved. Nothing was implanted in the control group (group 1), and five chitosan pellets (60 mg/pellet) were implanted in group 1, three OsteoSet pellets (100 mg/pellet) in group 3, and four calcium sulfate-chitosan composite pellets (1 pellet, 80 mg; calcium sulfate 40 mg/pellet, chitosan 40 mg/pellet) in group 4. For each group, a radiographic study, bone mineral density test, three-point bending test, and histologic examination were performed in the second, fourth, and sixth weeks. In the radiologic study, in group 1, cortical bone was not formed even at 6 weeks. In group 2, it was observed at 6 weeks. In groups 3 and 4, cortical bone was partially seen around the fourth week. At 6 weeks, it was clearly observed on both sides, and the projection of the marrow cavity became distinctive, so bone consolidation was considered to be much progressed. The bone mineral density test and three-point bending test results appeared to be highly similar in groups 3 and 4 and in groups 2 and 1. Particularly at 6 weeks, the measures for groups 3 and 4 were statistically significant compared with those for groups 1 and 2 (P < 0.05). In histologic examination, new bone formation began to be seen at 2 weeks in all groups, but it was more active and faster in groups 3 and 4. At 6 weeks, fibrous connective tissue still remained at the center in groups 1 and 2; however, the fibrous connective tissue at the center was replaced with callus, the bony bridge was obvious, and lamellation of callus was observed more in groups 3 and 4. The results indicate that chitosan pellets, OsteoSet, and chitosan-calcium sulfate composite pellets facilitate new bone formation on defected bone, and that particularly OsteoSet and chitosan-calcium sulfate composite pellets are more effective than chitosan.

Animals↗
PubMedDate not supplied

[Callus problem].

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Bony Callus↗
PubMed2004

[Reconstruction of posttraumatic bony defects of the lower extremity: callotaxis or free vascularized fibula graft?].

PURPOSE/BACKGROUND: Several methods have been established for the treatment of bony defects of the lower extremity. The purpose of this paper is to evaluate the use of a free vascularized fibula graft for these defects in comparison to callotaxis and segmental transport. METHOD AND CLINICAL MATERIAL: Retrospective analysis of data from 32 patients treated between 1981 and 1999 at the University Hospital in Zurich, Switzerland with bony defects of the lower extremity. RESULTS: The reconstruction of the bony defect was successful in 80 % with fibula graft, in 94 % with callotaxis and in 83 % with segmental transport. In the group with the fibula transplantation 2.6 re-interventions due to complications had to be performed, in the callotaxis group there were 3.6 and in the segmental transport group 5.2 surgical re-interventions. The time between primary intervention and full weight bearing was 16 months in the fibula transplantation group, 7.6 months in the callotaxis group and 10.7 months in the segmental transport group. CONCLUSION: The results show that these three options can be used for different indications. Reconstruction can be planned according to the following rules: Segmental bony defects of the entire circumference of up to 5 cm are best treated by initial shortening followed by callus distraction. Bony defects from 5 to 12 cm are best treated by segmental transport while maintaining limb length. Defects > 12 cm are best treated by reconstruction with a vascularized free fibula graft.

Accidents, Traffic↗
PubMed2003

The fracture gap size influences the local vascularization and tissue differentiation in callus healing.

BACKGROUND: Revascularization of a fracture depends on fracture stability and fracture gap conditions. The aim of the study was to determine quantitatively the revascularization and tissue differentiation in an animal model with different fracture gaps and controlled biomechanical conditions. MATERIALS AND METHOD: The study was performed on ten sheep with an osteotomy on the right metatarsal. The fracture was stabilized by an external fixator that allowed adjustable axial interfragmentary movement. Two groups of five sheep each were adjusted to a medium sized gap (M, 2.1 mm) and a large gap (L, 5.7 mm) under comparable interfragmentary strain (30-32%). The animals were killed after 9 weeks, and the metatarsals were prepared for undecalcified histology and analysis of tissue differentiation and vessel distribution. RESULTS: Group M showed significantly more revascularization (M=1.62, L=0.85 vessels/mm2), more bone formation (M=37.2%, L=13.9%) and less fibrocartilage tissue (M=18.1%, L=39.1%) than group L. Larger vessels (>40 microm) were found mainly in the medullary channel, and smaller vessels (<20 microm) mainly in the peripheral callus. Histologically, group M showed partial bony bridging of the osteotomy gap, and the group L had delayed healing. CONCLUSION: A good reduction of a fracture with small interfragmentary gaps is important for its revascularization and healing.

Animals↗
PubMed2004

The influence of cyclic compression and distraction on the healing of experimental tibial fractures.

Interfragmentary displacement has a main effect on callus formation in fracture healing. To test whether compressive or distractive displacements have a more pronounced effect on new bone formation, a sheep osteotomy model was created whereby the gap tissue was subjected to constant bending displacement. A diaphyseal osteotomy with a gap of 2 mm was created in 18 sheep tibiae and stabilized with a special unilateral actuator-driven external fixator. Two experimental groups with six sheep each received either 10 or 1000 cycles evenly distributed over 24 h. The third group of six sheep served as a control group without actively induced displacement. The amount and direction of cyclic displacement was kept constant throughout the observation period, resulting in 50% compressive and 50% distractive displacement within the osteotomy gap. At sacrifice, six weeks after surgery, bending stiffness was measured and new bone formation was assessed radiologically and microradiographically. In all cycled groups, the amount of periosteal callus formation was up to 25 times greater on the compression compared to the distraction side (p < 0.001). The application of the higher number of daily cycles resulted in an up to 10-fold greater amount of periosteal new bone formation on the compression side (p < 0.012), while the difference on the distraction side was not significant. Ten cycles applied a day were sufficient to create an abundant periosteal callus on the compression side. In the 1000 cycle group, bending stiffness revealed slightly lower values but the difference was not significant. Solid periosteal bridging of the gap was observed in two sheep in the control group, whereas bridging in the cycled groups was observed exclusively at the medullary side. In conclusion, cyclic compressive displacements were found to be superior over distractive displacements. A higher number of enforced and maintained compressive displacements enhanced periosteal callus formation but did not allow bony bridging of the gap.

Animals↗