Fracture Site (fracture + site)

Distribution by Scientific Domains


Selected Abstracts


ROCK-SURFACE TEMPERATURES OF BASALT IN THE DRAKENSBERG ALPINE ENVIRONMENT, LESOTHO

GEOGRAFISKA ANNALER SERIES A: PHYSICAL GEOGRAPHY, Issue 3 2007
STEFAN GRAB
ABSTRACT. Rock temperature data are presented for a variety of topographic localities at a high Drakensberg site. The objective is to investigate the spatiotemporal variations of surface rock temperatures in high Drakensberg basalt. The temperature results are then used to discuss possible implications for thermal stress fatigue and frost-induced weathering. TinytalkÔ data loggers and probes were used for rock-surface temperature recording. Long-term measurements were recorded over 12 months from May 2002 to April 2003, at a 1-hour logging interval and rock depth of 1 cm for a highaltitude (3300 m a.s.l.) interfluve and fracture site. Whilst the north-facing rock surface experiences negligible hours below ,3°C, the south-facing rock surface and interfluve sites are subjected to considerable periods below ,3°C, which falls within the ,frost cracking window'. It is concluded that the substantial contrasts of recorded rock thermal parameters over small spatial scales between various topographic settings, highlight that site-specific measurements across the broader scale are required for an adequate evaluation of regional weathering and its associated landform development. [source]


Hepatocyte Growth Factor Contributes to Fracture Repair by Upregulating the Expression of BMP Receptors,

JOURNAL OF BONE AND MINERAL RESEARCH, Issue 10 2005
Yuuki Imai MD
Abstract Hepatocyte growth factor (HGF) is activated and the expression of BMP receptors (BMPRs) is induced around the fracture site during the early phase of fracture repair. HGF facilitates the expression of BMPRs in mesenchymal cells. This study suggests that HGF contributes to fracture repair by inducing the expression of BMPRs. Introduction: The precise mechanisms that control the upregulation of BMP, BMPRs, and other molecules involved in bone repair are not completely understood. In this study, we hypothesized that HGF, activated through the action of thrombin on the HGF activator, may enhance BMP action through the local induction of BMP or BMPRs. Materials and Methods: Callus samples from tibial fractures in mice were harvested for immunohistochemical analysis of HGF and phosphorylated c-Met, for in situ hybridization of BMPRs, and for real-time RT-PCR analysis for the expression of HGF, c-Met, and BMPRs. To study the changes in gene expression of BMPRs in response to HGF, C3H10T1/2 cells were cultured with or without HGF and harvested for real-time RT-PCR and for Western blot analysis. To evaluate the contribution of HGF to the biological action of BMP2, C3H10T1/2 cells and primary muscle-derived mesenchymal cells were precultured with HGF and cultured with BMP2. In addition, the expression of the luciferase gene linked to the Id1 promoter containing the BMP responsive element and alkaline phosphatase (ALP) activity were assayed. Results: Positive immunostaining of HGF and phosphorylated c-Met was detected around the fracture site at 1 day after the fracture was made. mRNA expression of BMPRs was increased 1 day after fracture and localized in mesenchymal cells at the fracture site. From an in vitro study, the expression of mRNA for BMPRs was elevated by treatment with HGF, but the expression of BMP4 did not change. Western blot analysis also showed the upregulation of BMPR2 by HGF treatment. The results from the luciferase and ALP assays indicated increased responsiveness to BMPs by treating with HGF. Conclusions: This study indicates that HGF is activated and expressed at the fracture site and that HGF induces the upregulation of BMPRs in mesenchymal cells. Furthermore, HGF may facilitate BMP signaling without altering the expression of BMP molecules. [source]


Recombinant human platelet-derived growth factor BB (rhPDGF-BB) and beta-tricalcium phosphate/collagen matrix enhance fracture healing in a diabetic rat model

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 8 2009
Loay Al-Zube
Abstract Diabetes mellitus is a common systemic disease that has been associated with poor fracture healing outcomes. The mechanism through which diabetes impairs bone regeneration is unknown. One possible mechanism may be related to either decreased or uncoordinated release of local growth factors at the fracture site. Indeed, previous studies have found reduced platelet-derived growth factor (PDGF) levels in the fracture callus of diabetic rats, suggesting that local application of PDGF may overcome the negative effects of diabetes and promote fracture healing. To test this hypothesis, low (22 µg) and high (75 ug) doses of recombinant human PDGF-BB (rhPDGF-BB) were applied directly to femur fracture sites in BB Wistar diabetic rats that were then compared to untreated or vehicle-treated animals. rhPDGF-BB treatment significantly increased early callus cell proliferation compared to that in control specimens. Low dose rhPDGF-BB treatment significantly increased callus peak torque values (p,<,0.05) at 8 weeks after fracture as compared to controls. High dose rhPDGF-BB treatment increased callus bone area at 12 weeks postfracture. These data indicate that rhPDGF-BB treatment ameliorates the effects of diabetes on fracture healing by promoting early cellular proliferation that ultimately leads to more bone formation. Local application of rhPDGF-BB may be a new therapeutic approach to treat diabetes-impaired fracture healing. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 1074,1081, 2009 [source]


Global gene profiling reveals a downregulation of BMP gene expression in experimental atrophic nonunions compared to standard healing fractures

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 7 2006
Takahiro Niikura
Abstract Nonunion is a challenging problem that may occur following certain bone fractures. However, there has been little investigation of the molecular basis of nonunions. Bone morphogenetic proteins (BMPs) play a significant role in osteogenesis. However, little is known about the expression patterns of BMPs in abnormal bone healing that results in nonunion formation. These facts prompted us to investigate and compare the gene expression patterns of BMPs and their antagonists in standard healing fractures and nonunions using rat experimental models. Standard closed healing fractures and experimental atrophic nonunions produced by periosteal cauterization at the fracture site were created in rat femurs. At postfracture days 3, 7, 10, 14, 21, and 28, total RNA was extracted from the callus of standard healing fracture and fibrous tissue of nonunion (n,=,4 per each time point and each group). Gene expression of BMPs, BMP antagonists, and other regulatory molecules were studied by methods including Genechip® microarray and real-time quantitative RT-PCR. Gene expression of BMP-2, 3, 3B, 4, 6, 7, GDF-5, 7, and BMP antagonists noggin, drm, screlostin, and BAMBI were significantly lower in nonunions compared to standard healing fractures at several time points. Downregulation in expression of osteogenic BMPs may account for the nonunions of fracture. The balance between BMPs and their endogenous antagonists is critical for optimal fracture healing. © 2006 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 24:1463,1471, 2006 [source]


Accuracy and precision of radiostereometric analysis in the measurement of three-dimensional micromotion in a fracture model of the distal radius

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 2 2005
Rami Madanat
Abstract The purpose of the current study was to verify the feasibility of radiostereometric analysis (RSA) in monitoring three-dimensional fracture micromotion in fractures of the distal radius. The experimental set-up consisted of a simulated model of an extra-articular Colles' fracture, including metallic beads inserted into the bone on either side of the fracture site. The model was rigidly fixed to high precision micrometer stages allowing controlled translation in three axes and rotation about the longitudinal and transverse axes. The whole construct was placed inside a RSA calibration cage with two perpendicular radiographic film cassettes. Accuracy was calculated as the 95% prediction intervals from the regression analyses between the micromotion measured by RSA and actual displacements measured by micrometers. Precision was determined as the standard deviation of five repeated measurements of a 200 ,m displacement or a 0.5° rotation along a specific axis. Translations from 25 ,m to 5 mm were measured with an accuracy of ±6,m and translations of 200,m were measured with a precision of 2,6 ,m. Rotations ranging from 1/6° to 2° were measured with an accuracy of ±0.073° and rotations of 1/2° were measured with a precision of 0.025°,0.096°. The number of markers and their configuration had greater impact on the accuracy and precision of rotation than on those of translation. Aside from the unknown rate of clinical marker loosening, the current results favor the use of at least four markers in each bone fragment in distal radius fractures. These results suggest a strong rationale for the use of RSA as an objective tool for comparing different treatment modalities and novel bone graft substitutes aimed at stabilization of fractures of the distal radius. © 2004 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved. [source]


A reliable externally fixated murine femoral fracture model that accounts for variation in movement between animals

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 5 2003
Chris K. Connolly
Abstract Fifty-two CFLP mice had an open femoral diaphyseal osteotomy held in compression by a four-pin external fixator. The movement of 34 of the mice in their cages was quantified before and after operation, until sacrifice at 4, 8, 16 or 24 days. Thirty-three specimens underwent histomorphometric analysis and 19 specimens underwent torsional stiffness measurement. The expected combination of intramembranous and endochondral bone formation was observed, and the model was shown to be reliable in that variation in the histological parameters of healing was small between animals at the same time point, compared to the variation between time-points. There was surprisingly large individual variation in the amount of animal movement about the cage, which correlated with both histomorphometric and mechanical measures of healing. Animals that moved more had larger external calluses containing more cartilage and demonstrated lower torsional stiffness at the same time point. Assuming that movement of the whole animal predicts, at least to some extent, movement at the fracture site, this correlation is what would be expected in a model that involves similar processes to those in human fracture healing. Models such as this, employed to determine the effect of experimental interventions, will yield more information if the natural variation in animal motion is measured and included in the analysis. © 2003 Orthopaedic Research Society. Published by Elsevier Science Ltd. All rights reserved. [source]


Microsurgical reconstruction of brachial artery injuries in displaced supracondylar fracture humerus in children

MICROSURGERY, Issue 7 2006
Hassan H. Noaman M.D.
Between March 2000 and March 2005, 840 children with grade III supracondylar humeral fractures presented for treatment, consecutively at our hospital. One hundred twenty had absent or diminished (detected by Doppler but not palpable) radial pulse on initial examination. Eighty-nine of these 120 children recovered pulse (palpable) after closed reduction and percutaneous pinning of the fracture. The remaining 31 children had persistent absent radial pulse. Twenty-two of the 31 children had median nerve signs. Each of these 31 children was explored. The intraoperative findings were intact median nerve in all cases (neuropraxia), traumatic aneurysm with thrombus formation in 17 cases, complete injury of the brachial artery in 8 cases (loss of continuity), thrombosis in 3 cases, partial tear in 2 cases, and brachial artery entrapment in the fracture site in 1 case. Microsurgical reconstruction of the 31 brachial arteries was done as the following: reversed vein graft for 8 cases, excision and repair in 17 cases, partial repair in 2 cases, thrombectomy in 3 cases, and release of the brachial artery from the fracture site in 1 case. The average follow up was 26 months range (6,60) months. All children had excellent to good functional and cosmetic outcome except one who had Volkman's ischemic contracture, treated later by free functioning gracilis muscle transfer. © 2006 Wiley-Liss, Inc. Microsurgery, 2006. [source]


Anterior versus posterior approach in reconstruction of infected nonunion of the tibia using the vascularized fibular graft: potentialities and limitations

MICROSURGERY, Issue 3 2002
Sherif M. Amr M.D.
The potentialities, limitations, and technical pitfalls of the vascularized fibular grafting in infected nonunions of the tibia are outlined on the basis of 14 patients approached anteriorly or posteriorly. An infected nonunion of the tibia together with a large exposed area over the shin of the tibia is better approached anteriorly. The anastomosis is placed in an end-to-end or end-to-side fashion onto the anterior tibial vessels. To locate the site of the nonunion, the tibialis anterior muscle should be retracted laterally and the proximal and distal ends of the site of the nonunion debrided up to healthy bleeding bone. All the scarred skin over the anterior tibia should be excised, because it becomes devitalized as a result of the exposure. To cover the exposed area, the fibula has to be harvested with a large skin paddle, incorporating the first septocutaneous branch originating from the peroneal vessels before they gain the upper end of the flexor hallucis longus muscle. A disadvantage of harvesting the free fibula together with a skin paddle is that its pedicle is short. The skin paddle lies at the antimesenteric border of the graft, the site of incising and stripping the periosteum. In addition, it has to be sutured to the skin at the recipient site, so the soft tissues (together with the peroneal vessels), cannot be stripped off the graft to prolong its pedicle. Vein grafts should be resorted to, if the pedicle does not reach a healthy segment of the anterior tibial vessels. Defects with limited exposed areas of skin, especially in questionable patency of the vessels of the leg, require primarily a fibula with a long pedicle that could easily reach the popliteal vessels and are thus better approached posteriorly. In this approach, the site of the nonunion is exposed medial to the flexor digitorum muscle and the proximal and distal ends of the site of the nonunion debrided up to healthy bleeding bone. No attempt should be made to strip the scarred skin off the anterior aspect of the bone lest it should become devitalized. Any exposed bone on the anterior aspect should be left to granulate alone. This occurs readily when stability has been regained at the fracture site after transfer of the free fibula. The popliteal and posterior tibial vessels are exposed, and the microvascular anastomosis placed in an end-to-side fashion onto either of them, depending on the length of the pedicle and the condition of the vessels themselves. To obtain the maximal length of the pedicle of the graft, the proximal osteotomy is placed at the neck of the fibula after decompressing the peroneal nerve. The distal osteotomy is placed as distally as possible. After detaching the fibula from the donor site, the proximal part of the graft is stripped subperiosteally, osteotomized, and discarded. Thus, a relatively long pedicle could be obtained. To facilitate subperiosteal stripping, the free fibula is harvested without a skin paddle. In this way, the use of a vein graft could be avoided. Patients presenting with infected nonunions of the tibia with extensive scarring of the lower extremity, excessively large areas of skin loss, and with questionable patency of the anterior and posterior tibial vessels are not suitable candidates for the free vascularized fibular graft. Although a vein graft could be used between the recipient popliteal and the donor peroneal vessels, its use decreases flow to the graft considerably. These patients are better candidates for the Ilizarov bone transport method with or without free latissimus dorsi transfer. © 2002 Wiley-Liss, Inc. MICROSURGERY 22:91,107 2002 [source]


Stromal cell,derived factor 1/CXCR4 signaling is critical for the recruitment of mesenchymal stem cells to the fracture site during skeletal repair in a mouse model

ARTHRITIS & RHEUMATISM, Issue 3 2009
Toshiyuki Kitaori
Objective Stromal cell,derived factor 1 (SDF-1; CXCL12/pre,B cell growth-stimulating factor) is a dominant chemokine in bone marrow and is known to be involved in inflammatory diseases, including rheumatoid arthritis. However, its role in bone repair remains unknown. The purpose of this study was to investigate the role of SDF-1 and its receptor, CXCR4, in bone healing. Methods The expression of SDF-1 during the repair of a murine structural femoral bone graft was examined by real-time polymerase chain reaction and immunohistochemical analysis. The bone graft model was treated with anti,SDF-1 neutralizing antibody or TF14016, an antagonist for CXCR4, and evaluated by histomorphometry. The functional effect of SDF-1 on primary mesenchymal stem cells was determined by in vitro and in vivo migration assays. New bone formation in an exchanging-graft model was compared with that in the autograft models, using mice partially lacking SDF-1 (SDF-1+/,) or CXCR4 (CXCR4+/,). Results The expression of SDF1 messenger RNA was increased during the healing of live bone grafts but was not increased in dead grafts. High expression of SDF-1 protein was observed in the periosteum of the live graft. New bone formation was inhibited by the administration of anti,SDF-1 antibody or TF14016. SDF-1 increased mesenchymal stem cell chemotaxis in vitro in a dose-dependent manner. The in vivo migration study demonstrated that mesenchymal stem cells recruited by SDF-1 participate in endochondral bone repair. Bone formation was decreased in SDF-1+/, and CXCR4+/, mice and was restored by the graft bones from CXCR4+/, mice transplanted into the SDF-1+/, femur, but not vice versa. Conclusion SDF-1 is induced in the periosteum of injured bone and promotes endochondral bone repair by recruiting mesenchymal stem cells to the site of injury. [source]


Giant basal cell carcinoma masquerading as an osteogenic sarcoma

AUSTRALASIAN JOURNAL OF DERMATOLOGY, Issue 1 2009
Paul Cherian
SUMMARY An 88-year-old man presented to the dermatology outpatient clinic with an 11-month history of a rapidly growing mass overlying a clavicular fracture site. The lesion was 8 × 6 cm, painful, fixed to deeper structures and ulcerated. Superficial and deep biopsies yielded invasive basal cell carcinoma. Imaging demonstrated extensive soft tissue invasion into muscle, bone and potentially into the lung parenchyma. Due to complications arising from subsequent diagnostic procedures, the patient declined further invasive tests. The cutaneous lesion was treated with palliative radiotherapy. We explore the literature regarding the tumorigenic effects of peri-fracture cytokines on the biological behaviour of basal cell neoplasms. [source]


Surgical repair of rib fractures in 14 neonatal foals: case selection, surgical technique and results

EQUINE VETERINARY JOURNAL, Issue 7 2004
F. BELLEZZO
Summary Reasons for performing study: Fractured ribs are encountered quite frequently in newborn Thoroughbred foals, often with fatal outcome. Surgical repair of fractures therefore requires consideration as a means of reducing mortality. Objectives: To evaluate the repair of rib fractures using internal fixation techniques in foals at 2 different equine hospitals following similar diagnostics and case selection. Methods: The records of 14 foals that underwent internal fixation of fracture ribs were reviewed. Subject details, clinical presentation, diagnosis, surgical technique, post operative care and complications were recorded. Follow-up information was obtained in 7 foals. Results: The fractured ribs were reduced and stabilised using reconstruction plate(s), self-tapping cortical screws and cerclage wire in 12 cases, Steinmann pins and cerclage wires in 1 case and both techniques in 1 case. Not every rib was reduced on each case. Surgical reduction was performed on an average of 2 ribs, range 1,3 ribs in each foal. At the time of writing, 4 foals had been sold, one age 2 years was in training and 2 others died from unrelated causes. Conclusions: Our data support the use of surgical stabilisation utilising reconstruction plates, self-tapping cortical screws and cerclage wire for selected cases of thoracic trauma in neonatal foals. The use of Steinmann pins may be suboptimal due to cyclic failure, implant migration and the potential for iatrogenic internal thoracic trauma. Potential relevance: Foals with existing extensive internal thoracic trauma resulting from rib fracture(s), or the potential for such trauma, previously considered to have a guarded to poor prognosis for survival, may be successfully managed with internal fixation of selected fracture sites. [source]


Lyophilization to improve drug delivery for chitosan-calcium phosphate bone scaffold construct: A preliminary investigation

JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 1 2009
Benjamin T. Reves
Abstract Lyophilization was evaluated in chitosan-calcium phosphate microspheres and scaffolds to improve drug delivery of growth factors and antibiotics for orthopedic applications. The dual delivery of an antibiotic and a growth factor from a composite scaffold would be beneficial for treatment of complex fracture sites, such as comminuted fractures and segmental bone defects. The aim of this investigation was to increase the loading capacity of the composite by taking advantage of the increased porosity, due to lyophilization, and to produce an extended elution profile using a secondary chitosan-bead coating. The physiochemical properties of the composite were investigated, and loading and elution studies were performed with alkaline phosphatase (ALP), bone morphogenetic protein-2 (BMP-2), and amikacin. Lyophilization was found to increase the surface area of scaffolds by over 400% and the porosity of scaffolds by 50%. Using ALP as a model protein, the loading capacity was increased by lyophilization from 4.3 ± 2.5 to 24.6 ± 3.6 ,g ALP/mg microspheres, and the elution profile was extended by a supplemental chitosan coating. The loading capacity of BMP-2 for composite microspheres was increased from 74.4 ± 3.7 to 102.1 ± 8.0 ,g BMP-2/g microspheres with lyophilization compared with nonlyophilized microspheres. The elution profiles of BMP-2 and the antibiotic amikacin were not extended with the supplemental coating. Additional investigations are planned to improve these elution characteristics for growth factors and antibiotics. © 2009 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009 [source]


Recombinant human platelet-derived growth factor BB (rhPDGF-BB) and beta-tricalcium phosphate/collagen matrix enhance fracture healing in a diabetic rat model

JOURNAL OF ORTHOPAEDIC RESEARCH, Issue 8 2009
Loay Al-Zube
Abstract Diabetes mellitus is a common systemic disease that has been associated with poor fracture healing outcomes. The mechanism through which diabetes impairs bone regeneration is unknown. One possible mechanism may be related to either decreased or uncoordinated release of local growth factors at the fracture site. Indeed, previous studies have found reduced platelet-derived growth factor (PDGF) levels in the fracture callus of diabetic rats, suggesting that local application of PDGF may overcome the negative effects of diabetes and promote fracture healing. To test this hypothesis, low (22 µg) and high (75 ug) doses of recombinant human PDGF-BB (rhPDGF-BB) were applied directly to femur fracture sites in BB Wistar diabetic rats that were then compared to untreated or vehicle-treated animals. rhPDGF-BB treatment significantly increased early callus cell proliferation compared to that in control specimens. Low dose rhPDGF-BB treatment significantly increased callus peak torque values (p,<,0.05) at 8 weeks after fracture as compared to controls. High dose rhPDGF-BB treatment increased callus bone area at 12 weeks postfracture. These data indicate that rhPDGF-BB treatment ameliorates the effects of diabetes on fracture healing by promoting early cellular proliferation that ultimately leads to more bone formation. Local application of rhPDGF-BB may be a new therapeutic approach to treat diabetes-impaired fracture healing. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 1074,1081, 2009 [source]


Steroid hormones strongly support bovine articular cartilage integration in the absence of interleukin-1,

ARTHRITIS & RHEUMATISM, Issue 12 2006
Carsten Englert
Objective Posttraumatic integration of articular cartilage at fracture sites is essential for mechanical stability of cartilage, and ruptured cartilage is a prerequisite for early osteoarthritis. This study was undertaken to investigate effects on articular cartilage integration mediated by steroid hormones, interleukin-1, (IL-1,), and combinations thereof. Methods Articular cartilage blocks were cultured in partial apposition for 2 weeks with ascorbic acid, testosterone, 17,-estradiol, and dehydroepiandrosterone (DHEA), with or without IL-1,. Mechanical integration was measured as adhesive strength, i.e., the maximum force at rupture of integrated cartilage blocks divided by the overlap area. Glycosaminoglycan content was used to study synthesized extracellular matrix. Results Culture in medium without supplements did not lead to integration (adhesive strength 0 kPa). With administration of ascorbic acid (100 ,g/ml), the median adhesive strength was 49 kPa. In comparison with ascorbic acid alone, all steroid hormones induced a strong, concentration-dependent stimulation of integration (with maximum values observed with DHEA at 3 × 10,5M, testosterone at 10,8M, and 17,-estradiol at 10,11M). For testosterone and 17,-estradiol, this was also reflected by an increase of glycosaminoglycan content. Adhesive strength was increased with IL-1, at 10 pg/ml, but not at 1 pg/ml or 100 pg/ml. In the presence of both IL-1, and sex hormones, integration of articular cartilage was reduced. Conclusion This is the first study to demonstrate that steroid hormones such as 17,-estradiol, DHEA, and testosterone stimulate articular cartilage integration. This effect is abrogated by low concentrations of IL-1,. In the absence of IL-1, or after neutralization of IL-1,, steroid hormones might be favorable adjuvant compounds to optimize cartilage integration. [source]