Acid hydrolases and bone resorption in the remodelling phase of the development of bony fracture callus.
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Acid Phosphatase↗
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Dose-dependent effects of combined IGF-I and TGF-beta1 application in a sheep cervical spine fusion model.
Combined IGF-I and TGF-beta1 application by a poly-(D,L-lactide) (PDLLA) coated interbody cage has proven to promote spine fusion. The purpose of this study was to determine whether there is a dose-dependent effect of combined IGF-I and TGF-beta1 application on intervertebral bone matrix formation in a sheep cervical spine fusion model. Thirty-two sheep underwent C3/4 discectomy and fusion. Stabilisation was performed using a titanium cage coated with a PDLLA carrier including no growth factors in group 1 ( n=8), 75 micro g IGF-I plus 15 micro g TGF-beta1 in group 2 ( n=8), 150 micro g IGF-I plus 30 micro g TGF-beta1 in group 3 ( n=8) and 300 micro g IGF-I plus 60 micro g TGF-beta1 in group 4 ( n=8). Blood samples, body weight and temperature were analysed. Radiographic scans were performed pre- and postoperatively and after 1, 2, 4, 8, and 12 weeks. At the same time points, disc space height and intervertebral angle were measured. After 12 weeks, the animals were killed and fusion sites were evaluated using quantitative computed tomographic (CT) scans to assess bone mineral density, bone mineral content and bony callus volume. Biomechanical testing was performed and range of motion, and neutral and elastic zones were determined. Histomorphological and histomorphometrical analysis were carried out and polychrome sequential labelling was used to determine the time frame of new bone formation. In comparison to the group without growth factors (group 1), the medium- and high-dose growth factor groups (groups 3 and 4) demonstrated a significantly higher bony callus volume on CT scans, a higher biomechanical stability, an advanced interbody bone matrix formation in histomorphometrical analysis, and an earlier bone matrix formation on fluorochrome sequence labelling. Additionally, the medium- and high-dose growth factor groups (groups 3 and 4) demonstrated a significantly higher bony callus volume, a higher biomechanical stability in rotation, and an advanced interbody bone matrix formation in comparison to the low-dose growth factor group (group 2). No significant difference could be determined between the medium- and the high-dose growth factor groups (groups 3 and 4, respectively). The local application of IGF-I and TGF-beta1 by a PDLLA-coated cage significantly improved results of interbody bone matrix formation in a dose-dependent manner. The best dose-response relationship was achieved with the medium growth factor dose (150 micro g IGF-I and 30 micro g TGF-beta1). With an increasing dose of these growth factors, no further stimulation of bone matrix formation was observed. Although these results are encouraging, safety issues of combined IGF-I and TGF-beta1 application for spinal fusion still have to be addressed.
Animals↗
Distal metacarpal sequestration in a bison.
A 2-year-old 400-kg female American bison was admitted for evaluation and treatment of an open fracture of the right metacarpal bones 3 and 4. Radiography revealed osteolysis of the distal metaphysis and epiphysis, with extensive bony callus formation along the dorsoproximal and proximomedial aspects extending distally to the proximomedial aspect of the proximal phalanx. Evidence of periosteal or bony proliferation at the fracture site or along the distal segment of the third and fourth metacarpal bones was not visible, suggesting that the distal fracture fragment was becoming a sequestrum. Treatment consisted of soft tissue debridement and placement of the limb in a full-limb cast. The cast was changed every 4 weeks until the sequestrum was removed and the bone healed. It is rare for the distal half of a long bone to sequester following fracture. Additionally, it is remarkable that the sequestrum served as a buttress, which prevented collapse of the bone until the sequestrum was replaced by functional bony callus.
Animals↗
Extracortical bridging callus after limb salvage surgery about the knee.
The increasing survival of children treated for osteosarcoma has led to an increase in limb sparing surgery. Little published information is available about the postoperative imaging appearance of this technique. Thus, information gleaned from medical records and imaging reviews was correlated with clinical outcome of 19 consecutive children (median age at diagnosis, 12.3 years) treated for distal femoral osteosarcoma with a cemented rotating hinged knee endoprosthesis with porous coated collar. An extracortical bridging bony callus was identified in 16 patients who were followed up after surgery for a median of 2.8 years (range, 1.4-6 years). Extracortical bridging bony callus formation was circumferential in eight and preferentially posterior in nine, and ranged from 0.5 to 0.7 cm in thickness; 14 patients had lucent lines subjacent to the bridging bone. Thirteen patients had good functional use of the surgically treated leg. Five patients had progressive metastatic disease develop. One patient had local disease recurrence 8 months after surgery. Extracortical bridging bone was not identified in three patients, two of whom had infection develop 7 months and 17 months after surgery; both infections required amputation. Extracortical bridging bone preferentially develops posteriorly, along the compression side of the femur, often is associated with subjacent lucency, and seems to reflect increased prosthetic stability.
Adolescent↗
Callus formation after bony resection in diabetic patients.
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Amputation, Surgical↗
Effect of bisphosphonate (incadronate) on fracture healing of long bones in rats.
This study was designed to test whether bisphosphonates disturb the process of fracture healing. Female Sprague-Dawley rats were injected with either two doses of bisphosphonate (incadronate) (10 microg/kg and 100 microg/kg) or vehicle three times a week for 2 weeks. Right femora were then fractured and fixed with intramedullary wires. Incadronate treatment was stopped in pretreatment groups (P-10 and P-100 groups), while the treatment was continued in continuous treatment groups (C-10 and C-100 groups). Animals were sacrificed at 6 and 16 weeks after surgery. Soft X-ray of all fractured femora was taken. After mechanical testing, fractured femora were stained in Villanueva bone stain and embedded in methyl methacrylate. Cross-sections near fracture line were analyzed by microradiography and histomorphometry. Radiographic study showed that bony callus was present in all the fractures and incadronate treatment led to a larger callus, especially in C-100 group at both 6 and 16 weeks. Histologic study showed that the process of fracture healing in pretreatment groups was delayed at 6 weeks, but reached control level thereafter and showed same characteristics as in control at 16 weeks. Woven bony callus could still be seen in continuous treatment groups at 16 weeks. Mechanical study indicated that the ultimate load of C-100 group was slightly higher than the other treatment groups and control. The results suggest that pretreatment with incadronate did not affect fracture healing at 16 weeks after fracture. However, continuous incadronate treatment could lead to larger callus, but it delayed remodeling process during fracture healing, especially with high-dose treatment.
Animals↗
Evaluation of autogeneic and allogeneic cortical chip grafting in a feline tibial nonunion model.
A feline tibial nonunion model was used to evaluate the efficacy of fresh autogeneic and deep-frozen allogeneic cortical chip grafts for bone repair. Rigidly fixated tibial ostectomies with a segmental defect length of 1 cm were grafted with 3 mm X 2 mm chips of cortical bone in 12 skeletally mature cats. Six cats were given fresh autogeneic bone (group A) and 6 were given deep-frozen allogeneic bone (group B). Bone healing was evaluated radiographically and histologically over a 12-week period. Consolidating bony callus and palpable stability of the tibia after bone plate removal were evident in all group A cats and 4 of the 6 group B cats by 12 weeks after surgery. Bone remodeling had progressed to intermediate restoration of diaphyseal structure in 2 cats of each group. Fibrous replacement of graft chips, absence of bony callus, and instability of the tibia after bone plate removal were evident in 1 group B cat at 12 weeks. The remaining group B cat was withdrawn from the study at 6 weeks due to loosening of the bone plate and screws.
Animals↗
[Study on in vivo drug delivery and repairing large segmental infected bony defect with massive reconstituted bovine xenograft aided by calcium phosphate cement drug core].
OBJECTIVE: To find out an effective technique to repair large segmental infected bony defect. METHODS: Calcium phosphate cement (CPC) incorporated with bone morphogenetic protein and gentamycin was embedded in the massive reconstituted bovine xenograft (MRBX), then CPC-MRBX was obtained after CPC's solidification. In vivo test was applied to test the drug delivery capability of CPC-MRBX, in which it was implanted in the dorsal muscle pouch of 18 rabbits. The drug concentration of animal blood and surrounding soft tissue of the CPC-MRBX in the muscle pouch was measured 1, 2, 5, 10, 15, 20, 25, 30 and 35 d after operation, 2 rabbits each time. Large segmental infected femur defect in the rabbit model was created to test the repairing capability of CPC-MRBX. External fixation was done 1.5-2.0 cm above the knee, the most adjacent nail to fracture site was 0.5-0.8 cm away, and proper pressure was applied to the graft. In experimental group (n = 25), the bony defect was replaced by CPC-MRBX, while in the control group(n = 15) dissected bone block was re-implanted in original position. The animal was subjected to radiographic, histological examination at 4, 8, 16 and 24 weeks. The general condition was observed after the operation. RESULTS: CPC-MRBX was easily made under normal temperature and pressure. In vivo drug delivery test showed that the drug concentration of the tissue remained above the minimal inhibitory concentration of staphylococcus 30 d after operation and no significant increase of blood drug concentration was observed. In experimental group, no adverse influence was observed. Four weeks after operation, the animal could bear load, bony callus around the graft was observed by X-ray, and abundant chondral tissues that grew into CPC-MRBX were observed by histological method. Eight weeks after operation, progressively increasing bony callus around the graft was observed, external fixation could be removed, normal function was restored, and CPC was degenerated dramatically while new bone tissues were growing. Sixteen weeks after the operation, more new bone tissues grew and CPC was degenerated further while marrow tissues were taking shape. Twenty-four weeks after the operation, femur healed completely and CPC was degenerated completely. In the control group, the autograft remained unhealed on X-ray at 4 weeks, and osteomyelitis manifestation such as inflammatory cells infiltration and osteolysis was detected at 4 weeks. All the animals in the control group died before the 8th week, 4 of which showed positive hemoculture. CONCLUSION: CPC-MRBX is readily available and can be applied to repairing large segmental infected bony defect.
Animals↗
[BMP-2 gene modified tissue-engineered bone repairing segmental tibial bone defects in goats].
OBJECTIVE: To evaluate the effectiveness of the tissue-engineered bone substitute loaded with adenovirus mediated human bone morphogenetic protein-2 gene (Adv-hBMP-2) transfected bone marrow derived mesenchymal stem cells (BMSC) in the repair of diaphyseal segmental bone defect of large animal. METHODS: The right tibial bone defects (2.6 cm) model of 26 goats were established and divided into 5 groups: I. Adv-hBMP-2 transfected BMSC/calcined bone (CB) group (n = 9); II. adenovirus-beta-galactosidase (Adv-betagal) gene transfected BMSC/CB group (n = 6); III. untransfected BMSC/CB group (n = 6); IV. single CB group (n = 3); VI. untreated group (n = 2). The above tissue-engineered bone substitutes were implanted in the bone defects respectively except group VI. Roentgenography, histomorphometrical analysis and biomechanical measurement were studied at various times. RESULTS: X-ray: at 4 - 8th weeks after implantation, more bony callus was found in the bone defects of group I. The complete healing rates of group I, II, III, IV, and V were 5/8, 1/5, 0/5, 0/2, 0/1 respectively at 26th week after implantation. Histomorphometrical analysis showed much more new bony callus including cortical bone formed in group I than those of other groups. The compression strength of the implanted bone substitute of group I is significantly higher than those of group II and III. CONCLUSION: The tissue-engineered bone substitute loaded with human BMP-2 gene transfected BMSC can repair diaphyseal segmental bone defect of large animal (goat).
Animals↗
IGF-I and TGF-beta1 application by a poly-(D,L-lactide)-coated cage promotes intervertebral bone matrix formation in the sheep cervical spine.
STUDY DESIGN: A sheep cervical spine interbody fusion model was used to determine the effect of combined insulin-like growth factor-I (IGF-I) and transforming growth factor-beta-1 (TGF-beta1) applied by a poly-(D,L-lactide) (PDLLA)-coated cage. OBJECTIVES: The purpose of this study was to determine the effect of a new PDLLA carrier system, and to evaluate the effect of combined IGF-I and TGF-beta1 application in a sheep cervical spine model. SUMMARY AND BACKGROUND DATA: Growth factors such as bone morphogenic protein-2 have been shown to promote spine fusion and to overcome the disadvantages of an autologous bone graft. The optimum growth factor for promoting spinal fusion and the optimum method for delivering such growth factors are still a matter of discussion. METHOD: In this study, 32 sheep underwent C3-C4 discectomy and fusion: Group 1 (autologous tricortical iliac crest bone graft; n = 8), Group 2 (titanium cage; n = 8), Group 3 (titanium cage coated with a PDLLA carrier; n = 8), and Group 4 (titanium cage coated with a PDLLA carrier including IGF-I [5% w/w] and TGF-beta1 [1% w/w; n = 8). Blood samples, body weight, and body temperature were analyzed. Radiographic scans were performed before and after surgery, then at 1, 2, 4, 8, and 12 weeks, respectively. At the same time points, the disc space height, intervertebral angle, and lordosis angle were measured. After 12 weeks, the animals were killed, and fusion sites were evaluated using functional radiographic views of the animals in flexion and extension. Quantitative computed tomographic scans were performed to assess bone mineral density, bone mineral content, and bony callus volume. Biomechanical testing of the motion segment C3-C4 was performed in flexion, extension, axial rotation, and lateral bending. The stiffness, range of motion, neutral zone, and elastic zone were determined. Histomorphologic and histomorphometric analysis was performed, and polychrome sequential labeling was used to determine the time frame of new bone formation. RESULTS: There were no differences between the groups in terms of blood counts, body weight, and temperature. Over a 12-week period, cage Groups 2 to 4 showed significantly higher values for the intervertebral angle than for the bone graft. Functional radiographic assessment showed significantly lower residual flexion-extension movement in Group 4 than in any other group. The PDLLA-coated cages with IGF-I and TGF-beta1 showed significantly higher values for bone mineral density, bone mineral content, and bony callus volume. The average stiffness in rotation and bending was significantly higher, and the range of motion, neutral zone, and elastic zone in rotation were significantly lower in Group 4 than in any other group. Although only one animal in Group 4 demonstrated solid bony fusion after 12 weeks, histomorphometric evaluation showed a more progressed bone matrix formation in the group that had PDLLA-coated cages with IGF-I and TGF-beta1 than in any other group. Polychrome sequential labeling showed accelerated intervertebral bone matrix formation in Group 4. CONCLUSIONS: The findings showed that PDLLA coating of cervical spine interbody fusion cages as a delivery system for growth factors was effective. Although IGF-I and TGF-beta1 application by a PDLLA-coated interbody cage was not able to achieve solid bony fusion during the 12-week follow-up period, these growth factors significantly increased the results of interbody bone matrix formation. Additional longer-term studies are required to determine whether combined IGF-I and TGF-beta1 application leads to a successful spinal fusion.
Absorbable Implants↗
[Experimental fusion of the sheep cervical spine. Part II: Effect of growth factors and carrier systems on interbody fusion].
INTRODUCTION: A sheep cervical spine interbody fusion model was used to determine the effect of different carriers and growth factors on interbody bone matrix formation. The purpose of this study was to compare the efficacy and safety of combined IGF-I and TGF-beta1 application with BMP-2 application in spinal fusion. Additionally, a new poly (D, L-lactide) carrier system was compared to a collagen sponge carrier. METHOD: Forty sheep underwent C3/4 discectomy and fusion: group 1: titanium cage ( n=8), group 2: titanium cage coated with a PDLLA carrier (n=8), group 3: titanium cage coated with a PDLLA carrier including BMP-2 ( n=8), group 4: titanium cage with a collagen carrier including BMP-2 ( n=8), and group 5: titanium cage coated with a PDLLA carrier including IGF-I and TGF-beta1 ( n=8). Blood samples, body weight, and temperature were analyzed. Radiographic scans were performed pre- and postoperatively and after 1, 2, 4, 8, and 12 weeks, respectively. At the same time points, disc space height (DSH) and intervertebral angle (IVA) were measured. After 12 weeks the animals were killed and fusion sites were evaluated using functional radiographic views in flexion and extension. Quantitative computed tomographic scans (QCT) were performed to assess bone mineral density (BMD), bone mineral content (BMC), and bony callus volume (BCV). Biomechanical testing was carried out in flexion, extension, axial rotation, and lateral bending. Range of motion (ROM), neutral zone (NZ), and elastic zone (EZ) were determined. Histomorphological and histomorphometrical analyses were performed and polychrome sequential labeling was used to determine the time frame of new bone formation. RESULTS: In comparison to the non-coated cages, all PDLLA-coated cages showed significantly higher values for BMD of the callus and bone volume/total volume ratio. In comparison to the cage groups (groups 1 and 2), the cage plus BMP-2 (groups 3 and 4) and the cage plus IGF-I and TGF-beta1 group (group 5) demonstrated a significantly higher fusion rate in radiographic findings, a higher biomechanical stability, an advanced interbody fusion in histomorphometric analysis, and an accelerated interbody fusion on fluorochrome sequence labeling. BMP-2 application by the PDLLA carrier system (group 3) demonstrated significantly higher bony callus volume than BMP-2 application by a collagen sponge carrier (group 4). The BMP-2 group (group 3) showed significantly lower residual motion on functional radiographic evaluation and higher intervertebral bone matrix formation on fluorochrome sequence labeling at 9 weeks in comparison to the IGF-I/TGF-beta1 group (group 5). In contrast, the IGF-I/TGF-beta1 group (group 5) showed a significantly higher bone mineral density of the callus than the BMP-2 group (group 3). CONCLUSION: PDLLA coating of cervical spine interbody fusion cages as a delivery system for growth factors was effective and safe. In comparison to the collagen sponge carrier, the new PDLLA carrier system was able to improve results of interbody bone matrix formation. Both growth factors (BMP-2 and combined IGF-I and TGF-beta1) significantly accelerated results of interbody fusion. Based on these preliminary results, the combined IGF-I/TGF-beta1 application yields results equivalent to BMP-2 application at an early time in anterior sheep cervical spine fusion.
Animals↗
[Effects of surface demineralization on fracture healing in rat tibias].
Surface demineralization of bone in vivo induces new cartilage and bone formation locally. We studied the effects of local surface demineralization of the tibia in the rat on the process of fracture healing. We found that demineralization for 20 minutes with 0.5N HCl induced in the first 10 days following fracture less cartilaginous callus, with less calcium and magnesium, as compared to controls. However, from the second week on, the amount of cartilaginous callus in HCl-treated and control fractured bones was similar. Bony callus was greater in HCl-treated bones throughout the experiment, but X-rays showed poor bone union 5-8 weeks following fracture. Surface demineralization of bone in vitro induces local cartilage and bone formation, but inhibits good fracture healing.
Animals↗
Expression of bone matrix proteins mRNA during distraction osteogenesis.
Distraction osteogenesis is a recently advanced principle of bone lengthening in which a bone separated by osteotomy is subjected to slow progressive distraction using an external fixation device. Appropriate mechanical tension-stress is believed not to break the callus but rather to stimulate osteogenesis. To study the molecular features of this process, the expression and localization of the mRNAs encoding osteopontin (OPN), osteocalcin (OC), matrix Gla protein (MGP), osteonectin (ON), and collagen type I and I during distraction osteogenesis were examined by in situ hybridization and Northern blot analysis. The process can be divided into three distinct phases: the lag phase for 7 days between osteotomy and the beginning of distraction, the distraction phase for 21 days, and the consolidation phase for several weeks. The histologic and molecular events taking place during the lag phase were similar to those observed in fracture healing. The osteotomy site was surrounded by external callus consisting of hyaline cartilage. As distraction started at the rate of 0.25 mm/12 h, the cartilaginous callus was elongated, deformed, and eventually separated into proximal and distal segments. The chondrocytes were stretched along the tension vector and became fibroblast-like in shape. Although morphologically these cells were distinguishable from osteogenic cells, they expressed OPN, OC, and alkaline phosphatase mRNAs. As distraction advanced, the cartilaginous callus was progressively replaced by bony callus by endochondral ossification and thereafter new bone was formed directly by intramembranous ossification. OPN mRNA was detected in preosteoblasts and osteoblasts at the boundary between fibrous tissue and new bone. ON, MGP, and OC mRNAs appeared early in the differentiation stage. The variety of cell types expressing mRNA encoding bone matrix proteins in distraction osteogenesis was much greater than that detected in the embryonic bone formation and fracture healing process. Moreover, the levels of OPN, ON, MGP, and OC mRNA expression markedly increased during the distraction phase. These results suggested that mechanical tension-stress modulates cell shape and phenotype, and stimulates the expression of the mRNA for bone matrix proteins.
Animals↗
Electret induced callus formation in the rat.
Wrapping the mid-femoral shaft of the rat with a Teflon film electret produced a bony callus in 9 out of 10 animals. This model of electret-induced callus formation should lend itself to the histo-biochemical study of electrically induced osteogenesis.
Animals↗
Callus stimulation in distraction osteogenesis.
Distraction osteogenesis has been described as in vivo tissue engineering. The ability to stimulate this process for the repair of bony defects or lengthening of congenitally shortened facial structures is likely to significantly impact the field of craniofacial surgery. The purpose of this study was to determine whether mechanical stimulation of the distracted rabbit mandible would accelerate the maturation of the bony callus when applied during the early consolidation period. Twenty adult New Zealand White rabbits underwent unilateral mandibular osteotomy. A uni-directional internal distractor device (Synthes, Paoli, Pa.) was positioned along a plane perpendicular to the line of osteotomy. After a 7-day latency period, distraction was commenced at a rate of 1.0 mm/day for 12 days in all animals. In a control group of 10 rabbits, a consolidation period of 8 weeks was observed before they were killed. In the experimental group of 10 rabbits, daily alternate compression and distraction of 1 mm (sequential compression and distraction) was performed for 3 weeks followed by a 5-week period of rigid fixation. Each animal received a dose of a fluorescent label at three different time points during the study: at the end of the distraction period, 3 weeks after the completion of the distraction phase, and 3 days before it was killed. All animals were killed 8 weeks after the completion of the distraction phase. Undecalcified histologic analysis and 3-point bending tests to failure were performed on the extracted mandibles. The results of the experimental and control groups were compared. Four animals in the control group and three animals in the experimental group were excluded from the study because of screw loosening resulting in distractor dislodgment or because of infection. On histologic analysis, cortical thickness at the center of the callus was found to be significantly greater in the experimental group compared with the control group when normalized to the contralateral hemimandible (83 percent versus 49 percent, respectively; p < 0.007). The ratio of cortical to cancellous bone in the distracted callus was uniformly found to be greater in the experimental specimens. The mineral apposition rate was calculated by using fluorescence microscopy and found to be significantly greater in the experimental group both during the period of sequential compression and distraction (3.2 microm/day versus 2.1 microm/day, p = 0.02) and after the period of sequential compression and distraction (1.4 microm/day versus 1.1 microm/day, p = 0.006). Mechanical testing revealed no significant differences in bending strength or stiffness between experimental or control groups (p = 0.54 and 0.47, respectively). This study has demonstrated that daily alternating compression and distraction of 1 mm amplitude during the early consolidation period has a stimulatory impact on callus formation with respect to osteoblastic activity, remodeling, and maturation of bone. Optimal timing and amplitude of sequential movement, long-term biomechanical differences, and molecular pathways have yet to be elucidated.
Animals↗
Callus originating in the laryngeal skeleton, presenting as a neck lump: a case report.
We report on the case of a young woman, presenting with a left lateral neck lump, which turned out to be a bony callus originating from the thyroid cartilage; similar but smaller lesions were found on the same side in the hyoid and cricoid cartilages. The CT, MRI and pathological findings are described.
Adult↗
Do serological tissue turnover markers represent callus formation during fracture healing?
Serological parameters of bone and fibrous tissue turnover were demonstrated to monitor the course of fracture healing. The aim of this study was to evaluate the correlation between the serological parameter levels during fracture healing and callus development in a standardised ovine model of fracture healing. Two years old female sheep received a standardised 3 mm tibial bone defect stabilised by an external fixator. The serological levels of the C-terminal propeptide of procollagen type I (PICP), bone specific alkaline phosphatase (bALP), total alkaline phosphatase (tALP), osteocalcin, tartrate-resistant acid phosphatase (TRAP), calcium, phosphate and the N-terminal peptide of procollagen type III (PIIINP) were observed over a 9-week healing period. The course of fracture healing was monitored radiographically, and the callus composition was evaluated histologically at 2, 3, 6 and 9 weeks post-surgery. The serological results were compared with an untreated control group. Additionally, the maximum values during healing were compared with juvenile values to gauge the level of the serological response. The histological and radiographical results demonstrated callus formation without complications. All serological parameters showed broad inter-individual variations, and the response to the standardised fracture scenario was strongly individual. Maximum values during fracture healing did not reach the juvenile levels. The fractured as well as the control animals showed significant changes in the parameter levels. No correlations were observed between the histological course of healing and the course of bone formation markers whilst the TRAP level was reduced during bony callus formation. The PIIINP level increased when the amount of soft callus tissue decreased during healing. The observed bone formation markers were not suitable as general markers to detect the course of fracture healing, whilst PIIINP was able to reflect soft callus degradation.
Acid Phosphatase↗
[Experimental histopathological studies of electrical callus formation and mechanism of bone healing by direct micro-electrical current].
In order to get better understanding of the effects of electrical stimulation on bone healing processes, the author compared the healing processes of the femur in dogs between two groups: a stimulation group and a control group (non-stimulation group) which were experimentally prepared. These bone specimens were periodically extirpated and used for pathological examinations and X-ray micro-analysis. In the stimulation group, strong proliferation of osteoblasts and new trabecular formation in the bone marrow were observed at the 3rd day, and transition from fibrous to bony callus were noted at the 9th day; after the 3rd week bone remodeling was sparsely seen and bone healing period was shortened. In electromicroscopic observation, calcification of bone matrix and bone remodeling also seemed to be facilitated in this group. However, no marked differences in histological process of bone healing were observed between the stimulation group and the control group.
Animals↗