Clinical outcomes of autogenous cancellous bone grafts obtained through the portal for tibial nailing

Effect of polydimethylsiloxane surface morphology on osteogenic differentiation of mesenchymal stem cells through SIRT1 signalling pathway

Constructing surface topography with a certain roughness is a widely used, non-toxic, cost-effective and effective method for improving the microenvironment of cells, promoting the proliferation and osteogenic differentiation of mesenchymal stem cells (MSCs), and promoting the osseointegration of grafts and further improving their biocompatibility under clinical environmental conditions. SIRT1 plays an important regulatory role in the osteogenic differentiation of bone marrow-derived MSCs (BM-MSCs). However, it remains unknown whether SIRT1 plays an important regulatory role in the osteogenic differentiation of BM-MSCs with regard to surface morphology. Polydimethylsiloxane (PDMS) with different surface morphologies were prepared using different grits of sandpaper. The value for BMSCs added on different surfaces was detected by cell proliferation assays. RT-qPCR and Western blotting were performed to detect SIRT1 activation and osteogenic differentiation of MSCs. Osteogenesis of MSCs was detected by alkaline phosphatase (ALP) and alizarin red S staining. SIRT1 inhibition experiments were performed to investigate the role of SIRT1 in the osteogenic differentiation of MSCs induced by surface morphology. We found that BM-MSCs have better value and osteogenic differentiation ability on a surface with roughness of PDMS-1000M. SIRT1 showed higher gene and protein expression on a PDMS-1000M surface with a roughness of 13.741 ± 1.388 µm. The promotion of the osteogenic differentiation of MSCs on the PDMS-1000M surface was significantly decreased after inhibiting SIRT1 expression. Our study demonstrated that a surface morphology with certain roughness can activate the SIRT1 pathway of MSCs and promote the osteogenic differentiation of BMSCs via the SIRT1 pathway.

Similarities and Differences of Induced Membrane Technique Versus Wrap Bone Graft Technique

BACKGROUND

There are no reports on the similarities and differences between induced membrane (IM) technique and wrap bone graft(WBG) technique.

OBJECTIVE

The aims of this study are to investigate the effects of IM technique and WBR technique in repairing segmental bone defects, and to analyze the similarities and differences between them.

MATERIALS AND METHODS

66 patients of tibial segmental bone defects treated by IM technique and WBG technique were retrospectively analyzed. Aged 13-69 years old with an average of 35.3 years old. IM technique was divided into early IM group (bone grafting at 6-8 weeks of bone cement filling) and late IM group (bone grafting after 8 weeks of bone cement filling). WBG was divided into titanium mesh group and line suturing cortical bone blocks group. There were 11 cases, 25 cases, 10 cases and 20 cases in the early IM group, late IM group, titanium mesh group and line suturing group, respectively. Bone healing, complications and functional recovery (Paley's method) were observed, the causes of nonunion and delayed union and factors affecting bone healing were analyzed.

RESULTS

There were no significant differences in terms of age, sex, defect length, course, fixation method, defect location and preoperative function of adjacent joints among the 4 groups. All patients were followed up for 12-50 months, with an average of 20.1 months. The clinical healing time of early IM group, late IM group, titanium mesh group and line suturing group were (5.81 ± 0.75) months, (7.56 ± 1.66) months, (7.50 ± 0.70) months and (7.81 ± 1.81) months, respectively, showing significant differences among the 4 groups (P = 0.005). However, only early IM group had significant difference with other groups (P < 0.05), while no significance was found between late IM group and WBR group, between titanium mesh group and suture group (P > 0.05). There were no significant differences in healing ration, complications and functional recovery of adjacent joints among the 4 groups (P > 0.05). There were 4 cases of nonunion and delayed union, all of which were caused by poor quantity or quality of bone graft or unstable bone graft or internal fixation.

CONCLUSION

Both IM technique and WBG technique are effective method for repairing segmental bone defects. In addition to mechanical encapsulation, early IM has biological osteogenesis. However, mechanical encapsulation is a common basis for repairing bone defects, and biological osteogenesis can enhance bone healing.

Measuring outcomes following tibial fracture

AIM

The aim of this study was to determine how outcome is measured following adult tibial fracture in the modern era of functional outcome measurement and patient reported outcomes.

METHODS

A systematic review of publications since 2009 was performed, looking specifically at acute, adult tibial shaft fractures. Ovid Medline, Embase, PubMed and PsycINFO databases were searched for relevant titles which were then screened by two authors with adjudication where necessary by a third. Relevant articles were reviewed in full and data was extracted concerning the study participants, study design and any measures that were used to quantify the results following fracture. The results were collated and patient reported outcome measures were assessed using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN) standards.

RESULTS

A total of 943 titles and articles were reviewed, with 117 included for full analysis. A wide range of clinical and radiological "outcomes" were described, along with named clinician- and patient-reported outcome measures. There was considerable heterogeneity and lack of detail in the description of the simplest outcomes, such as union, infection or reoperation. Reported clinician and patient reported outcome measures are variably used. None of the identified patient reported outcome measures have been validated for use following tibial fracture.

CONCLUSION

We recommend definition of a core outcome set for use following tibial fracture. This will standardise outcome reporting following these injuries. Furthermore, there is need for a validated patient reported outcome measure to better assess patient important outcomes in this patient group.

Human pseudoarthrosis tissue contains cells with osteogenic potential

INTRODUCTION

Nonunion is a challenging problem that may occur after certain bone fractures. The treatment of nonunion is closely related to its type. To develop an effective treatment strategy for each type of nonunion, biological analysis of nonunion tissue is essential. Pseudoarthrosis is a distinct pathologic entity of nonunion. To understand the pathology of pseudoarthrosis, we investigated the cellular properties of pseudoarthrosis tissue-derived cells (PCs) in vitro.

PATIENTS AND METHODS

PCs were isolated from four patients with pseudoarthrosis and cultured. Cells were evaluated for cell-surface protein expression by using flow cytometry. Osteogenic differentiation capacity was assessed by using Alizarin Red S staining, alkaline phosphatase (ALP) activity assay, and reverse transcription polymerase chain reaction (RT-PCR) after osteogenic induction. Chondrogenic differentiation capacity was assessed via Safranin O staining and RT-PCR after chondrogenic induction.

RESULTS

PCs were consistently positive for the mesenchymal stem cell-related markers CD29, CD44, CD105, and CD166, but were negative for the haematopoietic-lineage markers CD31, CD34, CD45, and CD133. Alizarin Red S staining revealed that PCs formed a mineralised matrix that was rich in calcium deposits after osteogenic induction. ALP activity under osteogenic conditions was significantly higher than that under control conditions. Gene expression of ALP, Runx2, osterix, osteocalcin, and bone sialoprotein was observed in PCs cultured under osteogenic conditions. Induced pellets were negatively stained by Safranin O staining. Gene expression of aggrecan, collagen II, collagen X, SOX5, and SOX9 was not observed.

CONCLUSION

We have shown for the first time the properties of cells in patients with pseudoarthrosis. Our results indicated that osteogenic cells existed in the pseudoarthrosis tissue. This study might provide insights into understanding the pathology of pseudoarthrosis and improving the treatment for pseudoarthrosis.

The synergistic effect of micro-topography and biochemical culture environment to promote angiogenesis and osteogenic differentiation of human mesenchymal stem cells

Critical failures associated with current engineered bone grafts involve insufficient induction of osteogenesis of the implanted cells and lack of vascular integration between graft scaffold and host tissue. This study investigated the combined effects of surface microtextures and biochemical supplements to achieve osteogenic differentiation of human mesenchymal stem cells (hMSCs) and revascularization of the implants in vivo. Cells were cultured on 10μm micropost-textured polydimethylsiloxane (PDMS) substrates in either proliferative basal medium (BM) or osteogenic medium (OM). In vitro data revealed that cells on microtextured substrates in OM had dense coverage of extracellular matrix, whereas cells in BM displayed more cell spreading and branching. Cells on microtextured substrates in OM demonstrated a higher gene expression of osteoblast-specific markers, namely collagen I, alkaline phosphatase, bone sialoprotein, and osteocalcin, accompanied by substantial amount of bone matrix formation and mineralization. To further investigate the osteogenic capacity, hMSCs on microtextured substrates under different biochemical stimuli were implanted into subcutaneous pockets on the dorsal aspect of immunocompromised mice to study capacity for ectopic bone formation. In vivo data revealed greater expression of osteoblast-specific markers coupled with increased vascular invasion on microtextured substrates with hMSCs cultured in OM. Together, these data represent a novel regenerative strategy that incorporates defined surface microtextures and biochemical stimuli to direct combined osteogenesis and re-vascularization of engineered bone scaffolds for musculoskeletal repair and relevant bone tissue engineering applications.

Bone regenerative medicine: classic options, novel strategies, and future directions

This review analyzes the literature of bone grafts and introduces tissue engineering as a strategy in this field of orthopedic surgery. We evaluated articles concerning bone grafts; analyzed characteristics, advantages, and limitations of the grafts; and provided explanations about bone-tissue engineering technologies. Many bone grafting materials are available to enhance bone healing and regeneration, from bone autografts to graft substitutes; they can be used alone or in combination. Autografts are the gold standard for this purpose, since they provide osteogenic cells, osteoinductive growth factors, and an osteoconductive scaffold, all essential for new bone growth. Autografts carry the limitations of morbidity at the harvesting site and limited availability. Allografts and xenografts carry the risk of disease transmission and rejection. Tissue engineering is a new and developing option that had been introduced to reduce limitations of bone grafts and improve the healing processes of the bone fractures and defects. The combined use of scaffolds, healing promoting factors, together with gene therapy, and, more recently, three-dimensional printing of tissue-engineered constructs may open new insights in the near future.

Bone regenerative medicine: classic options, novel strategies, and future directions

This review analyzes the literature of bone grafts and introduces tissue engineering as a strategy in this field of orthopedic surgery. We evaluated articles concerning bone grafts; analyzed characteristics, advantages, and limitations of the grafts; and provided explanations about bone-tissue engineering technologies. Many bone grafting materials are available to enhance bone healing and regeneration, from bone autografts to graft substitutes; they can be used alone or in combination. Autografts are the gold standard for this purpose, since they provide osteogenic cells, osteoinductive growth factors, and an osteoconductive scaffold, all essential for new bone growth. Autografts carry the limitations of morbidity at the harvesting site and limited availability. Allografts and xenografts carry the risk of disease transmission and rejection. Tissue engineering is a new and developing option that had been introduced to reduce limitations of bone grafts and improve the healing processes of the bone fractures and defects. The combined use of scaffolds, healing promoting factors, together with gene therapy, and, more recently, three-dimensional printing of tissue-engineered constructs may open new insights in the near future.