Effects of cyclic fluid stress at different frequencies on behaviors of cells incubated on titanium alloy.

The orthopedic external fixation is always in dynamic mechanical environment with the somatic movement. We used a self-designed mini oscillator to simulate this condition by providing the reciprocating cyclic fluid stress, and observed the behavioral responses of fibroblasts implanted on titanium alloy plane to the stress at different frequencies, including 0.2 Hz, 0.6 Hz, and 1.0 Hz. We found that the cell angle, shape index and expression of vinculin were mostly biphasic-dependent with the increase of frequency, with peaks at 0.6 Hz. Whereas the cell area, expression of Col-I and α-SMA were mainly affected by the 1.0 Hz stress. Interestingly, 1.0 Hz stress also promoted Col-I expression of bone marrow mesenchymal stem cells (BMSCs), although it did not increase α-SMA. These results reveal that 0.6 Hz stress improves the alignment, polarity and adherence of fibroblasts on titanium alloy substrates, thus improving the sealing of implants; the 1.0 Hz force activates the differentiation of fibroblasts into myofibroblasts and increases collagen produced by stem cells, which probably cause the formation of fibrous capsules around implants.

Salvianolic acid B attenuates spinal cord ischemia-reperfusion-induced neuronal injury and oxidative stress by activating the extracellular signal-regulated kinase pathway in rats.

BACKGROUND: Salvianolic acid B (SalB), the main bioactive compound isolated from the traditional Chinese medicinal herb broad Radix Salviae Miltiorrhizae exerts a spectrum of pharmacologic activities. We investigated the effects of SalB treatment in a rat model of spinal cord ischemia and reperfusion (I/R) injury and the underlying mechanism. MATERIALS AND METHODS: SalB was administered at 1, 10, or 50 mg/kg after spinal cord ischemia. The potential protective effects on spinal cord injury were determined by spinal cord edema, infarct volume, and motor function assessment of the hind limbs. RESULTS: SalB treatment significantly decreased spinal cord edema and infarct volume and preserved motor function of the hind limbs in a dose-dependent manner. SalB administration ameliorated the generation of oxidative products and preserved antioxidant defense activities in the injured spinal cord at both 4 and 24 h after I/R injury. Moreover, SalB prolonged the I/R injury-induced activation of extracellular signal-regulated kinase (ERK), and blocking ERK activation with PD98059 partially prevented the neuroprotective effects of SalB. CONCLUSIONS: These findings demonstrate the neuroprotective effects of SalB in a spinal cord I/R injury model and suggest that SalB-induced neuroprotection was mediated by ERK activation.

Precise resection and biological reconstruction under navigation guidance for young patients with juxta-articular bone sarcoma in lower extremity: preliminary report.

BACKGROUND: It is a challenge to perform a joint-preserving resection for young patients with juxta-articular bone sarcomas. We determined whether osteotomy under image-guided navigation make joint-saving resection possible for juxta-articular lesions while adhering oncological principles. METHODS: Between June 2008 and July 2010, joint-preserving limb salvage surgeries were performed on 9 patients with juxta-articular bone sarcomas under navigation guidance. Computed tomography/magnetic resonance imaging fusion images were used for real-time navigation. Eight lesions located around the knee and 1 in hip. Six tumors extend to and 3 beyond the epiphyseal line. Planned osteotomy under image-guided navigation was employed for achieving clear surgical margin while maximizing host tissue preservation. All tumors were en bloc removed and intercalary defect were reconstructed by combination of allograft with vascularized fibula graft. All specimens were examined for resection margin. Patients were followed up for an average of 25.2 months for evaluating of functional and oncology outcomes. RESULTS: Entire joint were preserved in 6 patients and part of joint were saved in another 3 patients. The mean registration error for navigation was 0.40 mm (range, 0.31 to 0.62 mm). Clear surgical margin was obtained in all specimens. The average closest distance between the osteotomy line and tumor edge was 9.6 mm (range, 6 to 14 mm). Entire joint cartilage was preserved in 6 patients and portion of joint were saved in 3 patients (2 in proximal tibia, 1 in distal femur). No patient experienced local recurrence. Two patients developed lung metastasis. One died of disease and the other underwent metastasectomy and had no evidence of disease at the most recent follow-up. All reconstruction was in situ with the Musculoskeletal Tumor Society average score of 26.7 at final follow-up. CONCLUSIONS: With careful patient selection, image navigation-assisted surgery made it possible to resect the bone exactly as planned in length and orientation in the magnetic resonance imaging image, yielding a clear margin and preserving the entire or part of the articular cartilage in joint-sparing limb salvage procedures for treating skeletally immature patients with juxta-articular bone sarcomas. LEVEL OF EVIDENCE: Level IV--therapeutic study.

Use of patient-specific templates in hip resurfacing arthroplasty: experience from sixteen cases.

PURPOSE: Hip resurfacing arthroplasty (HRA) is a technically demanding operation, requiring both accuracy and precision in placement of the acetabular and femoral components. Malalignment of the component can lead to notching and possible femoral neck fractures. We used specific templates created using a rapid prototyping machine based on the patients' anatomy, to aid in accurate intraoperative pin placement. METHODS: A 3D model of the hip was reconstructed using spiral computed tomography (CT) data by Amira 3.1 software in 16 patients in whom HRA was planned for hip osteoarthritis (OA). All of the patients in the study had normal contralateral hips. The rotational centre of femoral head on the normal side was superimposed using Imageware12.0 software to determine the centre of the femoral head on the contralateral side. The data was then used to produce patient-specific templates using a rapid prototyping technique. These templates were designed according to the anatomical features of femoral head surface, the rotation centre and the planned prosthesis shaft angle. The orientation of the prosthesis was determined by matching the model to the femoral head surface during the operation. In addition, a control group of 18 patients with OA was operated upon by the conventional method. RESULTS: The mean prosthesis stem shaft angle (SSA), as determined from postoperative imaging, was 138.68 ± 8.85° for the locating template group, and (118.9 ± 12.8) for the conventional group. CONCLUSIONS: The locating template designed and constructed preoperatively can provide precise and dependable location for hip resurfacing femoral components during arthroplasty and ensure the valgus stem placement necessary for optimal outcomes.

[Establishment of Schatzker classification digital models of tibial plateau fractures and its application on virtual surgery].

OBJECTIVE: To explore the establishment of Schatzker classification digital model of tibial plateau fractures and its application in virtual surgery. METHODS: Proximal tibial of one healthy male volunteer was examined with 64-slice spiral computed tomography (CT). The data were processed by software Mimics 10.01 and a model of proximal tibia was reconstructed. According to the Schatzker classification criteria of tibial plateau fractures, each type of fracture model was simulated.Screen-captures of fracture model were saved from different directions.Each type of fracture model was exported as video mode.Fracture model was imported into FreeForm modeling system.With a force feedback device, a surgeon could conduct virtual fracture operation simulation.Utilizing the GHOST of FreeForm modeling system, the software of virtual cutting, fracture reduction and fixation was developed.With a force feedback device PHANTOM, a surgeon could manipulate virtual surgical instruments and fracture classification model and simulate surgical actions such as assembly of surgical instruments, drilling, implantation of screw, reduction of fracture, bone grafting and fracture fixation, etc. RESULTS: The digital fracture model was intuitive, three-dimensional and realistic and it had excellent visual effect.Fracture could be observed and charted from optional direction and angle.Fracture model could rotate 360 ° in the corresponding video mode. The virtual surgical environment had a strong sense of reality, immersion and telepresence as well as good interaction and force feedback function in the FreeForm modeling system. The user could make the corresponding decisions about surgical method and choice of internal fixation according to the specific type of tibial plateau fracture as well as repeated operational practice in virtual surgery system. CONCLUSION: The digital fracture model of Schatzker classification is intuitive, three-dimensional, realistic and dynamic. The virtual surgery systems of Schatzker classifications make the virtual surgery training more normalized, programmed and standardized.In addition, virtual surgery system can serve as a new tool for preoperative planning and surgeon-patient interactions.

[Three-dimensional flow perfusion culture enhances proliferation of human fetal osteoblasts in large scaffold with controlled architecture].

OBJECTIVE: To demonstrate the feasibility and benefits of custom designed perfusion bioreactor in conjunction with well-defined three-dimensional (3D) environment for enhanced proliferation and homogeneous distribution of human fetal osteoblasts in large scaffold in vitro. METHODS: Large-scale ß-tricalcium phosphate (ß-TCP) scaffolds with tightly controlled architectures were fabricated. And a custom designed perfusion bioreactor was developed. Human fetal osteoblasts were seeded onto the scaffolds, cultured for up to 16 days in static or flow perfusion conditions. At Days 4, 8 & 16 post-incubation, the proliferation and distribution of osteoblasts were determined by daily D-glucose consumption, cell viability (methyl thiazolyl tetrazolium (MTT) assay), histological evaluation and scanning electron microcopy (SEM). Sphere like structures observed in the SEM images were assessed by energy dispersive X-ray (EDX) analysis. RESULTS: In both static and perfusion cultures, the daily D-glucose consumption increased with prolonged time. The daily D-glucose consumption was significantly higher in the perfusion culture than that in static culture (P < 0.05). The increased cell viability with time during the culture was similar to the daily D-glucose consumption under both conditions. There was much greater cell viability under flow perfusion culture compared to static culture (P < 0.05). Flow perfused constructs demonstrated improved cell proliferation and a homogeneous layer composed of cells and extracellular matrix in channels throughout the whole scaffold. However, the cells were biased to periphery in scaffolds culture statically. Sphere like structures present in the matrix were identified as calcium phosphate nodules via EDX analysis. CONCLUSIONS: Flow perfusion culture plus well-defined 3D interconnected channel environments enhances the proliferation and improve the distribution of human fetal osteoblasts in large scaffolds. Scaffolds with controlled architecture may be a potential tool of studying the fluid flow configuration and cell behavior inside scaffold in details. And human fetal osteoblasts can be used as a cell source in large bone graft research.

[Experimental study of repairing femoral bone defects with nHA/RHLC/PLA scaffold composite with endothelial cells and osteoblasts in canines].

OBJECTIVE: To explore whether a tissue-engineered construct composed of autogenous endothelial cells, osteoblasts and a new bioresorbable nano-hydroxyapatite/recombinant human-like collagen/polylactic acid (nHA/RHLC/PLA) would enhance bone regeneration and repair femoral head defects in canine models. METHODS: The bone marrow stem cells (BMSCs) were isolated from bone marrow of canine ilium and cultured in Dulbecco's modified eagle medium:nutrient mixture F-12 culture media for 1 week and the second-generation BMSCs were further induced by osteogenic medium (1×10(-8) mol/L dexamethasone, 10 mmol/L B-sodium glycerophosphate and 50 µg/ml vitamin C) and by endothelial cell grow medium (vascular endothelial growth factor and basic fibroblast growth factor) for 14 days in vitro. Thus BMSCs were induced into ECs and OBs. After the second passage, cells were digested and collected.And cell density was adjusted to 1.0×10(6)/ml.The cells and nHA/RHLC/PLA scaffold were co-cultured for 2-4 hours then nHA/RHLC/PLA scaffold composites prepared. Cavity defects of 8 mm in diameter and 10 mm in height were made in femoral heads.The nHA/RHLC/PLA scaffold composited with ECs and osteoblasts (OBs) (group A) and composited with OBs (group B) were inserted into different defects while cell-free nHA/RHLC/PLA scaffold served as controls (group C). New bone formation and defect repair were evaluated at 3 and 6 months by radiographic examination, histology and bone histomorphometry. RESULTS: New bone formation was evident as early as 3 months in groups A, B and C.At 6 months, abundant bone tissue within defects was observed in group A. The control animals with cell-free scaffold showed less bone formation at both timepoints.The scaffold of nHA/RHLC/PLA was degraded and absorbed gradually with the formation of new bone tissues.Histology and bone histomorphometry further revealed significantly increased trabecular bones in group A compared with groups B and C at 6 months postimplantation (P < 0.01). CONCLUSION: More abundant new bone tissue may be found in the bone defect areas implanted with osteoblast-endotheliocyte composite than osteoblasts composite and scaffold materials only.ECs and osteoblasts derived from BMSC are ideal seed cells for repairing femoral head defects.

Irregular osteotomy in limb salvage for juxta-articular osteosarcoma under computer-assisted navigation.

BACKGROUND: Joint-preserving limb salvage surgery has been expected to have good functional outcomes. However, it is still a unsolved problem to perform a joint preserving resection for patients with juxta-articular osteosarcoma invading epiphyseal line. We determined whether irregular osteotomy under image-guided navigation make joint-saving resection possible for juxta-articular osteosarcoma while adhering oncological principles. METHODS: We performed joint-preserving limb salvage surgeries on six patients with juxta-articular osteosarcoma of the long bone. Three lesions located in humerus, two in tibia and one in femur. Two tumors extend to and four beyond the epiphyseal line. CT and MRI data fusion images were applied for intraoperative navigation. Planned irregular osteotomy under image-guided navigation was employed for obtaining clear surgical margin while maximizing host tissue preservation. All tumors were en bloc removed and intercalary defect were reconstructed by allograft in one and combination of allograft with vascularized fibula graft in five patients. All specimens were examined for resection margin. Patients were followed up for average of 17.5 months for evaluating of functional and oncology outcomes. RESULT: Entire joint were preserved in three patients and part of joint were saved in another three patients. Clear surgical margin was obtained in all specimens with a minimum of 6-mm distance between tumor and osteotomy line. No patient experienced a local recurrence. One patient developed lung metastasis and had no evidence of disease at the most recent follow-up. All allografts but one healed during the study period. The MSTS average score was 88.8% at final follow-up. CONCLUSIONS: With careful patient selection, the irregular osteotomy under navigation guidance was proved to be an effective and safe technique for precise tumor resection in joint preserving limb salvage procedures for treating patients with juxta-articular osteosarcomas.

Schwann Cells Accelerate Osteogenesis via the Mif/CD74/FOXO1 Signaling Pathway In Vitro.

Schwann cells have been found to promote osteogenesis by an unclear molecular mechanism. To better understand how Schwann cells accelerate osteogenesis, RNA-Seq and LC-MS/MS were utilized to explore the transcriptomic and metabolic response of MC3T3-E1 to Schwann cells. Osteogenic differentiation was determined by ALP staining. Lentiviruses were constructed to alter the expression of Mif (macrophage migration inhibitory factor) in Schwann cells. Western blot (WB) analysis was employed to detect the protein expression. The results of this study show that Mif is essential for Schwann cells to promote osteogenesis, and its downstream CD74/FOXO1 is also involved in the promotion of Schwann cells on osteogenesis. Further, Schwann cells regulate amino acid metabolism and lipid metabolism in preosteoblasts. These findings unveil the mechanism for Schwann cells to promote osteogenesis where Mif is a key factor.

Biological reconstruction using massive bone allograft with intramedullary vascularized fibular flap after intercalary resection of humeral malignancy.

BACKGROUND: Reconstruction after excision of the humeral malignancy is a challenging issue for the reconstructive surgeon. The combined use of a fibular flap and allograft can provide a reliable reconstructive option. This article describes the authors' experience with this technique for the treatment of segmental bone defects after resection of humeral malignancy. METHODS: From 2005 to 2008, seven patients that had intercalary resection of humeral malignancy underwent reconstruction with an allograft and vascularized fibula construct. Patients were examined clinically and radiographically. RESULT: The average age at time of operation was 16.7 years. The mean follow-up time was 27.7 months. The average length of the resected humeral segment was 10.6 cm and that of the fibula flap was 13.1 cm. The average time of union of fibula was 20.7 weeks and for union of allograft was 26.3 weeks. Incorporation of the fibula into the allograft was seen in three patients. There were no allograft fractures and no infections. Three patients had surgery-related complications including a temporary radial nerve paralysis in 1, wound dehiscence in 1, and clawed toes in 1. The MSTS average score was 95.2% at final follow-up. CONCLUSIONS: Intramedullary fibular flaps in combination with massive allografts provide an excellent option for reconstruction of large bony defects after humeral malignancy extirpation. The viability of the fibula is a cornerstone in success of reconstruction that prevents allograft nonunion and result in decreased time to bone healing, leading to earlier patient recovery and return of function.

The dose-effect of icariin on the proliferation and osteogenic differentiation of human bone mesenchymal stem cells.

Icariin had been reported as a potential agent for osteogenesis, but the dose-effect relationship needed further research to realize the clinical application of icariin. We isolated and purified human bone mesenchymal stem cells (hBMSCs) and stimulated them with different concentrations of icariin. The cytotoxicity of icariin was evaluated by the methylthiazolytetrazolium (MTT) assay method. The proliferation and osteogenic differentiation of such hBMSCs were investigated for different concentrations of icariin. We found that icariin had a dose-dependent effect on the proliferation and osteogenic differentiation of hBMSCs in a suitable concentration range from 10(-9) M to 10(-6) M, but at concentrations above 10(-5) M, the cytotoxicity limited its use. The extremely low cost of icariin and its high abundance make it appealing for bone regeneration.

The use of massive allograft with intramedullary fibular graft for intercalary reconstruction after resection of tibial malignancy.

Reconstruction after intercalary excision of tibia malignancy is challenging. The combined use of a vascularized fibular flap and allograft can provide a reliable reconstructive option. Eight patients underwent reconstruction with an allograft and vascularized fibula following tibia malignancy resection. Patients were examined clinically and radiographically. The average age of patients was 16.5 years. The mean follow-up time was 38.4 months. Contralateral free fibula flap was used in three patients and ipsilateral pedicle fibula in five. The average length of defect was 11.8 cm and of fibula flap was 15.9 cm. Primary union was achieved in seven patients. The average time for bone union was 5.8 months at fibula-tibia junction and 14.1 months at allograft-tibia junction. Five patients had 10 complications. The Musculoskeletal Tumor Society average score was 90.8% at final follow-up. Intramedullary fibular flap in combination with massive allografts provide an excellent option for reconstruction of large bony defects after tibial malignancy extirpation. Ipsilateral pedicle fibula transportation had the advantages of short operation time and avoidance of donor site complications compared with the contralateral free fibula transfer.

The use of allograft shell with intramedullary vascularized fibula graft for intercalary reconstruction after diaphyseal resection for lower extremity bony malignancy.

BACKGROUND: Reconstruction after excision of the femur and tibia malignancy is a challenging issue for the reconstructive surgeon. The combined use of a vascularized fibular flap and allograft can provide a reliable reconstructive option. This article describes the authors' experience with this technique for the treatment of large-segmental bone defects after intercalary resection of lower extremity malignancy. METHODS: From 2003 to 2008, 11 patients that had intercalary resection of lower extremity malignancy underwent reconstruction with an allograft and vascularized fibular construct. Time to union was recorded through evaluation of plain radiographs. Patients were examined clinically and radiographically and were assessed functionally with MSTS score. RESULT: The average age at time of operation was 18.5 years. The mean follow-up time was 34.1 months. The oncology result was continuous disease free in 7 patients, no evidence of disease in 2, alive with disease in 1, and died of disease in 1. Free vascularized fibula flap was used in 7 patients and ispilateral pedicle vascularized fibula in 4. The average length of the resected segment was 12.1 cm and that of the fibula flap was 16.2 cm. The primary unions were achieved in all patients except one with tibia reconstruction. The average time for bone union was 5.4 months at fibula-host junction and 11.8 months at allograft-host junction. There were no allograft fractures and no infections. Five patients had 7 local complications. The MSTS average score was 91.8% at final follow-up. The mean time of weight-bearing was 12.4 months. CONCLUSIONS: Intramedullary fibular flap in combination with massive allografts provide an excellent option for reconstruction of large-bony defects after lower extremity malignancy extirpation. The viability of the fibula is a cornerstone in success of reconstruction that prevents allograft nonunion and result in decreased time to bone healing, leading to earlier patient recovery and return of function.

Limb salvage surgery for calcaneal malignancy.

BACKGROUND: Advances in oncologic treatment modalities and wide resection have made limb salvage procedures in calcaneal malignancy increasingly possible. However, reconstructions of the calcaneal remain a major surgical challenge because of the rarity and specific anatomy of this condition. METHODS: we retrospectively reviewed five patients who had primary calcaneal malignancy and underwent total calcanectomy and reconstructions with the distally pedicled osteocutaneous folded fibular flap between 2001 and 2007. The diagnoses included chondrosarcoma in 2, Ewing's sarcoma in 2 and osteosarcoma in 1. Three tumors were classified as stage-II B lesions, one as I A and one as II A. Wide resection margins were achieved in all patients. The patients were followed up for a mean of 50.4 months (range, 32-76 months). Patients were examined clinically and radiographically and were assessed functionally with Musculoskeletal Tumor Society (MSTS) score and American Orthopaedic Foot and Ankle Society (AOFAS) score. RESULTS: Four patients had no evidence of disease, and lung metastasis was found in one patient who was alive with disease. No local recurrence occurred in this series. At latest evaluation four patients had no evident limp or limitation of daily activities and one patient had mild limp. The average MSTS 93 score and AOFAS score were 83.2% and 86.4% at the last follow-up, respectively. All fibular flaps survived and bone unions achieved successfully. Fibula hypertrophies were seen in three patients. The overall mean time for bone union was 6.2 months. The mean time to full weight-bearing was 8.6 months. The average two-point discrimination was 2.3 cm at the time of final follow-up. Two patients had surgery-related complications including hematoma in 1 and skin margin necrosis in 1. CONCLUSIONS: Following the wide resection of calcaneal malignancy, biological reconstruction using distally pedicled osteocutaneous fibular has proven to be a successful limb salvage procedure, offering satisfactory local tumor control and functional restoration of the lower extremity function.

[Tissue engineering vascularized bone repairing segmental femoral bone defects in rabbits].

OBJECTIVE: To investigate the effectiveness and mechanism of tissue engineering vascularized bone in repairing segmental femoral bone defects in rabbits. METHODS: Thirty-two rabbits were randomized into two groups (n = 16 each). A segmental and critical bone defect of 15 mm in length was made at left femur. In experimental group, the tissue engineering bone constructed from autologous bone marrow mesenchymal stem cells plus beta-tricalcium phosphate (beta-TCP) and vascular bundle was implanted into bony defect. In control group, there was no implantation of vascular bundle. Animals were sacrificed at 2, 4, 8 and 12 weeks post-implantation respectively. Histological observation was conducted to determine the process of new bone formation and remodeling. The expression of vascular endothelial growth factor (VEGF) in new bone was measured by immunohistochemistry, real-time PCR and Western blot. RESULTS: As indicated by histological observations over time, new bone formation increased in both groups. It was better in the experimental group than the control group at the beginning of 4 weeks. The expression level of VEGF gradually decreased in each group after an initial rise. And the expression of VEGF was significantly higher than the control group after implantation at all time points and peaked at 4 weeks. CONCLUSION: Tissue engineering vascularized bone accelerates bone repair in critical size defect model of femur in rabbit. Implantation of vascular bundle can promote the secretion of VEGF. And VEGF is an essential mediator of both angiogenesis and ossification.

The effect of fluid shear stress on fibroblasts and stem cells on plane and groove topographies.

In this study, we aimed to study the effect of fluid shear stress on fibroblasts and BMSCs on plane and groove topographies. The results showed that 0.6-Hz stress had the greatest influence on the alignment, polarity, migration and adhesion of fibroblasts on plane by increasing the expression of reoriented actin and vinculin; whereas 1.0-Hz stress promoted differentiation of fibroblasts into myofibroblasts by increasing Col-I and α-SMA expression. Interestingly, under the given frequency stress, the groove structure strengthened the above characteristics of fibroblasts beyond adhesion, and promoted differentiation of BMSCs into myofibroblasts. The above results indicate that 0.6 Hz may improve the implant-tissue sealing, while 1.0-Hz stress probably causes the disordered fiber deposition around implants.

[Postoperative implant-related complications after treatment of intertrochanteric fracture by gamma nail or by sliding hip screw: a meta-analysis].

OBJECTIVE: To evaluate and compare the postoperative implant-related complications after treatment of intertrochanteric fracture by gamma nail or by sliding hip screw. METHODS: Literatures on randomized controlled trials (RCTs) of the postoperative implant-related complications after treatment of intertrochanteric fracture by gamma nail or by sliding hip screw published before the end of June 2007 were retrieved from Cochrane library, Medline, Embase databank, and Chinese Biomedical Database. Relevant articles were handsearched in several Chinese journals. Methodology quality of the trials was critically assessed and data on postoperative implant-related complications were extracted. The software RevMan4.2.10 provided by the Cochrane Collaboration was used for meta-analysis. RESULTS: 10 RCTs and 3 quasi-RCTs involving 1857 cases were included. The results of meta-analysis showed that gamma nailing significantly increased the rate of postoperative femoral shaft fractures [RR = 3.75, 95%CI (1.47, 9.55), P = 0.006]. However, there were no statistic differences in the rates of lag screw cut-out and total mechanical complications between gamma nail and sliding hip screw treatment. CONCLUSION: Compared with sliding hip screw for intertrochanteric fractures, gamma nailing can lead to higher incidence of postoperative femoral shaft fractures. Fracture stability may influence the rate of postoperative implant-related complications. Further large sample and high quality RCTs based on fracture stability are required in order to provide more sufficient and reliable evidence.

[A study of the different effect on the expression of calcitonin gene related peptide and neuropeptide Y in tissue engineered bone with vascular bundle graft in vivo and that with sensory nerve tract graft in vivo].

OBJECTIVE: To evaluate the different effect on the expression of Calcitonin gene related peptide (CGRP)and neuropeptide Y (NPY) between tissue engineered bone with vascular bundle graft in vivo and that with sensory nerve tract graft in vivo. METHOD: Thirty-six healthy New Zealand rabbits were divided into 3 groups randomly and equally: vascular bundle group (A), sensory nerve tract group (B), tissue-engineering group (C). Group A segmental bone defect of 1.5 cm long was made at the right femur in each animal. After plate fixation, the defects were implanted respectively with the engineered bone prepared in the above-mentioned 3 methods. At 3, 6 and 12 months post-operatively, the distribution of CGRP and NPY in the new bone were detected by immunohistochemistry and analyzed semi-quantitatively by image analysis software. RESULTS: CGRP and NPY immuno-histochemical results indicated their contents increased significantly in all 3 groups as time passed (P = 0.000). Compared with group B, the contents of CGRP and NPY in group A significantly increased at 3 months (P = 0.000), but there was no statistic difference between them at 6 or 12 months (P > 0.05). The expression of CGRP and NPY in both group A and B were significantly more than that in group C at 3, 6 or 12 months (P = 0.000). CONCLUSION: Implantation of vascular bundle into tissue-engineered bone can significantly improve the CGRP and NPY contents at early 3 months comparing with Implantation of sensory tract into tissue-engineered bone, but the changes are not significant at 6 or 12 months post-operatively.

Trauma and pulmonary thromboembolism: an experimental study on their correlation.

OBJECTIVE: To investigate the correlation between trauma and pulmonary thromboembolism. METHODS: Comminuted fractures and extensive soft-tissue contusion at both hind limbs were made by a falling weight from a height in 16 rabbits. Lung perfusion scanning was performed to obtain the radioactivity counts before trauma, at 1 h, 48 h and 96 h after trauma. All the data were divided into 4 groups based on the above 4 time points. The rabbits were sacrificed when positive findings on the pulmonary perfusion scanning appeared. Their lungs were harvested to be paraffin-embedded and stained with hematoxylin-erosin method for histological examination of thromboembolism. The randomized block design ANOVA and the method of least significant difference (LSD) were used for statistical analysis of the radioactivity counts. RESULTS: The histological findings showed that pulmonary embolism developed in 6 of the 16 rabbits (37.5%). Five of the 6 pulmonary embolism rabbits presented neither clinical symptoms nor positive pulmonary embolism manifestations in the lung perfusion scanning. A significant difference was found in lung perfusion radioactivity between the pre-traumatic, post-traumatic 1h groups and post-traumatic 48 h and 96 h groups(P less than 0.05). CONCLUSIONS: Fractures of the hind limbs accompanied with extensive soft-tissue contusion may cause pulmonary micro-embolism that is not sensitive to lung perfusion scanning and tends to have no clinical symptoms. Pulmonary embolism development may take more than two days after trauma.

Distribution and property of nerve fibers in human long bone tissue.

OBJECTIVE: To observe the distribution of the nerve fibers in the bone tissue and the entry points of these fibers into the bone. METHODS: The adult tibia was used for the ground sections which were afterwards made into the slice sections by decalcification in ethylenediamine tetraacetic acid (EDTA). The ground sections were stained in silver and the slice sections were stained in silver and haematoxylin and eosin (HE) respectively. Then, the samples of the transmission electron microscope and the atomic force microscope were made and observed. RESULTS: In the human long bone tissue, many nerve fibers were distributed in the membrane, cortical bone, cancellous bone and marrow. The nerve fibers entered the bone from the nutrient foramen, and passed through the nutrient canal, Haversian's canal and Volkmann's canal, and finally into the bone marrow. In the nutrient canal, the nerve fibers, mainly the medullary nerve fibers, followed the blood vessel into the bone. In the cortical bone, the nerve fibers also followed the blood vessels and were mainly distributed along Haversian's canal and Volkmann's canal. In the bone trabecular and bone marrow, there were many nerve fiber endings arranged around the blood vessels, mainly around the tunica media of medium-size arteries in the marrow and around capillary blood vessels, and a few scattered in the bone marrow. There were sporadic nerve endings in epiphyseal plate and no nerve fibers permeated epiphysis to diaphysis. No distribution of nerve fibers could be found in cartilaginous part. CONCLUSIONS: There are many nerve fibers in bone and the nerve passageway is nutrient foramen, Volkman's canal, Haversian's canal and bone marrow.