Conventional Bone Grafting Research Articles

Clinical outcome of 302 zygomatic implants in 110 patients with a follow-up between 6 months and 7 years.

Zygomatic implant surgery is considered as a safe and successful alternative to the conventional implant surgery with bone grafts for patients with severe atrophic maxilla. The aim of this retrospective clinical case series was to report clinical outcome of zygomatic implants with a follow-up between 6 months and 7 years. A total of 110 patients with 302 zygomatic implants were included in this study. The intra and postoperative complications and survival rate of zygomatic implants were evaluated. The study included 110 consecutively treated patients with an age range of 21 to 76 years (mean 57.35 years, SD 10.42). The overall zygomatic implant survival rate was 98.34%. There were five implant failures in four patients. One intraoperative and 17 postoperative complications developed in 18 patients. There were no dropouts and the median follow-up of the patients was 41.75 months (with a range of 6-89 months). According to the results, in cases of severely atrophic posterior maxilla, zygomatic implant surgery can be considered as an effective and safe alternative to conventional implants and bone grafting procedures.

Topological optimization of 3D printed bone analog with PEKK for surgical mandibular reconstruction

PurposeThe purpose of this study was to analyze mechanical behaviors of a topologically optimized and 3D-printed mandibular bone block with polyetherketoneketone (PEKK) for surgical mandibular reconstruction. Materials and methods3D virtual mandibular models were reconstructed from cone beam computed tomography images. A proposed mandibular resection of the mandibular body (40 mm anterior-posteriorly) was segmented. Internal structure of the resected bone was designed with topological optimization. Dental implants and implant-supported crowns were integrated into the design. A second 3D virtual model was created with the same size and location of the defect but was reconstructed with a fibular graft and implant-supported crowns. The biomechanical behaviors of the two models were compared by finite element method (FEM) under the same boundary constraints and three loading locations, namely, central incisors, lower left and right side first molar areas. ResultsThe FEM results showed the maximum stresses and displacements of the topology optimized model were much lower than those of the model with fibular bone graft. The highest stress of the optimized mandibular model was located on the lower edge of the posterior border of bone analog, and fixation screws. The maximum displacement occurred at the lower edge of the proximal mandibular stump or the lower edge of the distal mandibular body on the contralateral site. Under the same three loading locations, the maximum stress of the optimized model significantly decreased by 67.9%, 71.9% and 68.6% compared to the fibular graft model. ConclusionsThe 3D printed bone analog with topological optimization is patient-specific and has advantages over the conventional fibular bone graft for surgical mandibular reconstruction. The optimized PEKK bone analog model creates more normal stress-strain trajectories than the fibular graft model and likely provides better functional and cosmetic outcomes.

Granular Honeycombs Composed of Carbonate Apatite, Hydroxyapatite, and β-Tricalcium Phosphate as Bone Graft Substitutes: Effects of Composition on Bone Formation and Maturation.

Material composition and porous structure are important factors in the formation and maturation of newly formed bone and replacement of materials by new bone. Conventional bone graft materials often lack suitability for bone generation because of the complexity of their macroporous structures, which can interfere with the penetration of cells related to bone remodeling and angiogenesis in the materials. In the present study, carbonate apatite (CO3Ap), hydroxyapatite (HAp), and β-tricalcium phosphate (TCP) honeycomb granules (HCGs) with uniformly sized macropores (∼115 μm) were fabricated. These HCG macropores were arranged in a regular fashion and penetrated straight into the granules. They were implanted into a rabbit femur defect for further evaluation. In the CO3Ap HCG implantation group, mature bone formed within CO3Ap HCG macropores by 4 weeks after grafting, and a large portion of CO3Ap HCGs was replaced by new bone at 12 weeks. By contrast, in the β-TCP HCG implantation group, new bone was not always formed in the regions after β-TCP HCG disappearance, and immature bone was present within β-TCP HCG macropores even after 12 weeks. HAp HCGs were not resorbed, and their macropores were filled with immature bone. The area of mature bone in the CO3Ap HCG implantation group was 3.3 and 1.6 times higher at 4 weeks and 2.2 and 1.7 times higher at 12 weeks compared with the HAp and β-TCP HCG implantation groups, respectively. Furthermore, the degrees of bone maturation for CO3Ap, HAp, and β-TCP HCGs were 100, 34, and 64% at 4 weeks, and 100, 54, and 69% at 12 weeks, respectively. Thus, the composition of the HCGs affected bone formation and maturation.

Bony Hypertrophy in Vascularized Fibular Grafts.

Background: Vascularized fibula graft (VFG) transfer is an established method of repairing large skeletal defects resulting from trauma, tumor resection, or infection. It obviates the process of creeping substitution that conventional bone grafts undergo and therefore exhibits better healing and improved strength. The aim of this study is to evaluate hypertrophy in VFG. Methods: We retrospectively reviewed patients undergoing VFG and studied immediate and late postoperative radiographs. Orthogonal views were measured for width of graft cortex and intramedullary canal, as well as adjacent recipient bone. Changes were measured for total cross sectional area, cortical area, intramedullary area, and graft width. Results: Thirty patients were included in the analysis, with recipient sites including 3 forearm, 4 humerus, 12 tibia, and 11 femur. Mean follow-up was 7.6 years (0.5-24.9 years). Patients' mean age was 31 (16-59 years). Average hypertrophy was 254% in early postoperative period and 340% in the late postoperative period. There was rapid graft hypertrophy in early postoperative period that plateaued with time. The width of the graft increased over time but didn't exceed the width of the adjacent recipient bone. In the later postoperative period, the size of graft intramedullary canal increased. Upper and lower extremity grafts showed similar hypertrophy. Conclusions: Using VFG to treat large skeletal defects is an attractive option in part due to the graft's ability to hypertrophy. We describe an early period of periosteal hypertrophy, followed by endosteal hypertrophy. These processes have relevance to function, mechanical strength, and surgical decision-making.

Nanofibrous poly(vinyl alcohol)/chitosan contained carbonated hydroxyapatite nanoparticles scaffold for bone tissue engineering.

A scaffold that mimics the physicochemical structure of bone at the nanoscale level is an attractive alternative to conventional bone grafts, but its development remains a main challenge in bone tissue engineering today. This work describes the fabrication of a nanofibrous poly(vinyl alcohol)/chitosan/carbonated hydroxyapatite (PVA/CS/CHAp) scaffold. CHAp nanoparticles were synthesized using a co-precipitation method, and nanofibrous PVA/CS/CHAp scaffolds were fabricated by electrospinning using CHAp concentrations of 0, 5, 10, 15, and 20 wt%. The physicochemical properties of the scaffolds were evaluated by SEM, XRD, FTIR, and EDS, and the mechanical properties were determined by tensile strength tests. Swelling behavior, protein adsorption onto the scaffold surfaces, surface biomineralization, and cells viability were also evaluated in vitro. The addition of CHAp to the composite decreased the fiber diameter from ∼160 nm at 0 wt% to ∼139 nm at 15 wt% and great agglomerations were evident at 20 wt%. XRD, FTIR, and EDS showed effective incorporation of CHAp into the nanofibrous structure. This CHAp incorporation significantly increased the modulus of the scaffold at PVA/CS/CHAp 15 wt%, with an average 103.86 MPa, but tensile strength was not significantly altered. However, the elongation at break was decreased as the CHAp concentration increased. Swelling capacity of scaffold increases due to CHAp addition. Protein adsorption onto the scaffold increased 2.3fold at 20 wt% when compared to 0 wt%. The PVA/CS/CHAp 15 wt% showed a better bioactivity when compared to PVA/CS/CHAp 0 wt% after immersion of the scaffolds in a simulated body fluid solution for 7 days. Cell viability and cell morphology results reveal that PVA/CS/CHAp able to facilitate osteoblast cells to attach and proliferate. Introducing higher CHAp into the scaffold could increase the cell viability of the scaffold. PVA/CS/CHAp has potential to serve as an alternative scaffold material for bone tissue engineering.

Tissue-engineered bone using mesenchymal stem cells versus conventional bone grafts in the regeneration of maxillary alveolar bone: A systematic review and meta-analysis.

The aim of this study was to compare tissue-engineered bone using mesenchymal stem cells (MSCs) and conventional bone grafts in terms of histomorphometric outcome, bone gained, and implant failure in the atrophic maxilla. A systematic review and meta-analysis of randomized clinical trials (RCTs) was conducted. An electronic search of several databases was performed. RCTs comparing tissue-engineered bone using MSCs to bone graft alone in rehabilitation of the atrophic maxilla were included. Outcome variables were a mean percentage of new bone formation, residual graft particles, and connective tissue. Bone gained and implant failure rate were also assessed. Risk ratio (RR) or standardized mean differences (SMD) were statistically analyzed. A total of 190 augmented sites enrolled in 12 RCTs were included in this study. Nine of the 12 RCTs included 153 maxillary sinuses that underwent sinus elevation, and three RCTs included 28 patients with bone grafting only. There was no significant increase in new bone formation between the two groups at 3 to 4 months (SMD = -0.232, CI, -0.659 to 0.195, low-quality evidence). However, at 6 months postgrafting, a statistically significant increase in new bone formation was found in favor of the tissue-engineered bone using the MSC group (SMD = 0.869%, CI, -1.98 to 9.310, moderate-quality evidence). No substantial difference was found between the two groups with respect to residual graft particles, connective tissue, bone gained, and implant failure rate (RR = 2.8, CI: 0.517 to 16.6, P = .226, very low-quality evidence). There is moderate- to very low-quality evidence supporting the use of tissue-engineered bone using MSC therapy in maxillary alveolar bone regeneration compared with conventional bone grafting without MSCs.

Autologous bone grafts vs bone graft substitutes in fracture healing in a tertiary care hospital of North India: A comparative study

Today as a result of rapid urbanization and mechanization there has been a rapid increase in the rate of trauma. As a result of this the treatment of post-traumatic conditions such as delayed unions, non- unions, malunions and other problems has become very challenging. In most cases it is possible to treat a fracture by restoring the alignment and stable fixation of the bone. However, in many cases additional measures such as bone grafting or bone transport are required to bring about bone healing or fill defects. This study will be comparing the efficacy and complications of bone grafts and bone graft substitutes and determining if bone graft substitutes are a worthy alternative to the conventional autologous bone graft.

Mechanistic role of perfusion culture on bone regeneration

Bone tissue engineering (BTE) aims to develop engineered bone tissue to substitute conventional bone grafts. To achieve this, culturing the cells on the biocompatible three-dimensional (3D) scaffold is one alternative approach. The new functional bone tissue regeneration could be feasible by the synergetic combinations of cells, biomaterials and bioreactors. Although the field of biomaterial design/development for BTE applications attained reasonable success, development of suitable bioreactor remains still a major challenge. Tissue engineering bioreactors provide the microenvironment required for neo-tissue regeneration, and also can be used to study the physio-chemical cues effect on cell proliferation and differentiation in order to produce functional tissue. In this direction, various bioreactors have been developed and evaluated for the successful development of engineered bone tissue. Continues assessment of tissue development and limitations of the bioreactors lead to the progression of perfusion flow bioreactor system. Improvements in perfusion reactor system were able to yield multiple tissue engineered constructs with uniform cell distribution, easy to operate protocols and also effectively handled for the functional tissue development to meet the adequate supply of engineered graft for clinical application.

Use of Recombinant Human Bone Morphogenetic Protein-2 at the C1-C2 Lateral Articulation without Posterior Structural Bone Graft in Posterior Atlantoaxial Fusion in Adult Patients

Posterior atlantoaxial fusion is an important armamentarium for neurosurgeons to treat several pathologies involving the craniovertebral junction. Although the potential advantages of recombinant human bone morphogenetic protein-2 (rhBMP-2) are well documented in the lumbar spine, its indication for C1-C2 fusion has not been well characterized. In our institution, we apply rhBMP-2 to the C1-C2 joint either alone or with hydroxyapatite, locally harvested autograft chips, and/or morselized allogenic bone graft for selected cases-without conventional posterior structural bone graft. We report the clinical outcomes of the surgical technique to elucidate its feasibility. We performed a single-center, retrospective review of data from 2008 to 2016 and identified 69 patients who had undergone posterior atlantoaxial fusion with rhBMP-2. The clinical records of these patients were reviewed, and the baseline characteristics, operative data, and postoperative complications were collected and statistically analyzed. The average age of the 69 patients was 60.8± 4.5 years, and 55.1% were women. With an average follow-up period of 21.1 ± 4.2 months, the C1-C2 fusion rate was 94.3% (65 of 69), and the average time to fusion was 11.4 ± 2.6 months (range, 5-23). The overall reoperation rate was 10.1% (7 of 69), with instrumentation failure in 7 patients (10.1%), adjacent segment disease in 2 (2.9%), and postoperative dysphagia and dyspnea in 2 patients (2.9%). No ectopic bone formation or soft tissue edema developed. Although retrospective and from a single center, our study has shown that rhBMP-2 usage at the C1-C2 joint without posterior structural bone grafting is a safe and reasonable surgical option.

Microstructural volumetric analysis of lateral ridge augmentation using differently conditioned tooth roots.

Previous research revealed that autogenous tooth roots may be biologically equivalent to conventional bone grafts for lateral ridge augmentation. However, these analyses were limited to two dimensions, whereas healing is a volumetric process. The present study aimed at volumetrically assessing the microstructure following lateral ridge augmentation using extracted tooth roots. The roots of differently conditioned maxillary premolars (i.e., healthy: PM-C; endodontically treated: PM-E; ligature-induced periodontitis: PM-P) and retromolar cortical autogenous bone (AB) blocks were used for lateral ridge augmentation at chronic-type defects in the lower quadrants of n = 16 foxhounds. At 12weeks, titanium implants were inserted and left to heal for another 3weeks. Tissue biopsies were scanned using microcomputed tomography (μCT), and volumes of interest were separated at the buccal and oral aspects to measure bone volume per tissue volume (BV/TV), trabecular thickness (Tb.Th), trabecular separation (Tb.Sp), and connectivity density (Conn.D). All groups investigated revealed comparable BV/TV, Tb.Th, Tb.Sp, and Conn.D values at either the augmented buccal or pristine oral aspects, respectively. A gradual but heterogeneous replacement of grafts was observed in all groups, but residual PM fragments were particularly noted in PM-C and PM-P groups. Differently conditioned PM and AB grafts were associated with a comparable bone microstructure within the grafted area. The duration of replacement resorption may vary considerably among the subjects. Autogenous tooth roots may serve as potential alternative to AB for localized alveolar ridge augmentation.

Application value of expansive pedicle screw in the lumbar short-segment fixation and fusion for osteoporosis patients.

Clinical value of expansive pedicle screw in lumbar short-segment fixation and fusion for patients with osteoporosis was investigated. A total of 80 patients with lumbar compression fracture but without obvious nerve compression were selected and divided into the observation group (n=40) and the control group (n=40) using a random number table. The observation group used the expansive pedicle screw, and the control group received conventional pedicle screw fixation and bone graft fusion. In the observation group, the operation and hospitalization time after operation were shorter and the intraoperative bleeding amount was less than that in control group (p<0.05). At 1 week, 1, 3 and 6 months after operation, the observation group had better straight leg raising test (SLRT) scores, higher lower limb sensory scores but lower visual analogue scale (VAS) scores than control group (p<0.05). Besides, the proportions of postoperative infection, dural mater tear, nerve root injury and spinal cord injury during operation in the observation group were lower than those in the control group (p<0.05), and the bone graft fusion rates at 3 and 6 months after operation were obviously superior to those in control group (p<0.05). Moreover, after operation, the spinal stenosis rate in the observation group was lower than that in control group (p<0.05), the vertebral height ratio was larger than that in control group (p<0.05), and the Cobb's angle was smaller than that in the control group (p<0.05). In addition, there was a negative correlation between bone mineral density (BMD) and hospitalization time after operation in the observation group (p<0.05). In conclusion, the internal fixation with expansive pedicle screw for osteoporosis patients with lumbar compression fracture is characterized by short operation time, less intraoperative bleeding, few complications, quick recovery of postoperative neurological function and satisfactory surgical effect. However, reasonable intervention in osteoporosis is also necessary.

Fenestration and debridement combined with percutaneous minimally invasive fibula implantation in the treatment of senile degenerative osteonecrosis of the femoral head: A study protocol for a non-randomized, controlled, clinical trial

Background and objectives: Osteonecrosis of the femoral head is one of the common forms of senile degenerative osteoarthropathy. The hip preservation surgery techniques that are currently commonly used include femoral head fenestration, debridement and bone grafting through an anterior approach, and debridement and impaction bone grafting with fibula support through a lateral approach with subtrochanter drilling. These two techniques cause great trauma to the patients, and surgery costs are high. Femoral head collapse occurs easily after surgery. The course inhibition of necrosis of the femoral head and repair effect are not ideal. Thus, we hope to develop a new repair method that can make up for the shortcomings of conventional hip preservation surgery. We will observe the therapeutic effect of fenestration and debridement combined with percutaneous minimally invasive fibula implantation. This low-cost procedure for senile osteonecrosis of the femoral head should have little intraoperative trauma. We will determine if it also prevents postoperative femoral head collapse. Design: This is a prospective, multicenter, non-randomized, controlled, clinical trial. Methods: Seventy patients (117 hips) with senile degenerative osteonecrosis of the femoral head will be recruited from the Hebei Provincial Youfu Hospital and the Third Hospital of Hebei Medical University, Shijiazhuang, China. The patients will be allocated into three groups according to the repair method. (1) Patients in the drilling debridement group will undergo conventional debridement and impaction bone grafting with fibula support through a lateral approach with subtrochanter drilling. (2) Patients in the fenestration debridement group will undergo conventional femoral head fenestration, debridement, and bone grafting through an anterior approach. (3) Patients in the combination repair group will undergo fenestration, debridement, and impaction bone grafting combined with percutaneous minimally invasive fibula implantation. Each group will include 39 hips. Follow-up will be conducted for 12 months. Outcome measures: The primary outcome measure is the incidence of femoral head collapse on the affected side at 12 months after surgery. The secondary outcome measures are intraoperative blood loss, operation time, hospital costs, and Harris hip score for hip function before surgery and 6 and 12 months after surgery and the incidence of adverse reactions at 6 and 12 months after surgery. Discussion: Our results can verify whether the effect of fenestration and debridement combined with percutaneous minimally invasive fibula implantation is better than those of the other two types of conventional hip preservation techniques in the treatment of senile osteonecrosis of the femoral head. In addition, we will validate whether the combined method clearly inhibits postoperative femoral head collapse and improves hip function. Ethics and dissemination: This trial has been approved by the Ethics Committee of Third Hospital of Hebei Medical University of China (approval number: KE2016-011-1). The study protocol will be conducted in accordance with the Declaration of Helsinki, formulated by the World Medical Association. Written informed consent will be obtained from all participants. This trial was designed in January 2014. Ethics approval was done in December 2014. The recruitment of subjects will begin in June 2018. Samples and data will be collected from June 2018 to June 2019. Outcome measures will be analyzed in August 2019. This trial will be completed in December 2019. The results of the trial will be reported in a scientific conference or disseminated in a peer-reviewed journal. Trial registration: This trial was registered in the Chinese Clinical Trial Registry (registration number: ChiCTR1800015124).

Block iliac bone grafting enhances osseous healing of alveolar reconstruction in older cleft patients: A radiological and histological evaluation.

BackgroundOlder alveolar cleft patients (&12 years old) often have wide bone defect as well as teeth loss, resulting in poor osseous healing with conventional alveolar bone grafting (ABG). In this study, we investigated a surgical technique of block iliac bone grafting for the alveolar cleft reconstruction and evaluated the clinical and radiological outcomes of these cleft patients.Material and MethodsFifteen patients were included in this study. All cases received preoperative cone bean computed tomography (CBCT) scans for the alveolar cleft evaluation. Osseous outcomes of block iliac bone grafting were assessed at 1 week, 3- and 6-month postoperatively. Volume changes and bone resorption rates were calculated using the measurement modules of Simplant software. Bone samples from one patient undergoing dental implantation were assessed by micro-CT and histological examination. The morbidities of donor-site were analyzed by clinical examination and questionnaire survey.ResultsThe average age of the case series was 18.53±2.50 years. The intraoral incision of thirteen cases healed well. However, two cases had oronasal fistula and graft exposure at 1-week postoperatively. The results of follow-up CBCT scans showed significant resistance to radiation on both sides of the bone graft, suggesting a good osseous healing and new bone formation. The mean residual bone volume was 1.68±0.26 cm3, 1.29±0.23 cm3 and 1.15±0.23 cm3 at 1-week, 3- and 6-month postoperatively. Correspondingly, the mean bone resorption rates in 3- and 6-month postoperative were 21.78±6.88% and 30.66±8.97%, respectively. From micro-CT and HE examinations, the block bone samples exhibited a cancellous structure in which mature bone trabecula and functional blood vessels appeared. The average scores of donor-site morbidities were drastically decreased at 3- and 6-month postoperatively compared with those at 1-week postoperatively.ConclusionsOur results demonstrated that block iliac bone grafting could achieve satisfying osseous outcomes in older alveolar cleft patients, and this technique provided favorable bony condition for further treatments, especially dental implantation. Key words:Alveolar bone grafting, Block bone grafting, Osseous healing, CBCT.

Understanding the molecular mechanism of improved proliferation and osteogenic potential of human mesenchymal stem cells grown on a polyelectrolyte complex derived from non-mulberry silk fibroin and chitosan

The development of engineered bone tissue, as a promising alternative to conventional bone grafts, has so far not proven successful and still remains challenging. Thus, attempts have been made in the present study to synthesize polyelectrolyte complex (PEC) scaffolds by blending chitosan (CS) to silk fibroin (SF) derived from the non-mulberry silkworm (Antheraea pernyi) at three different pH values (5.0, 6.0, and 7.0), and to characterize them in terms of morphology, ultrastructure and mechanical properties with scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy, x-ray diffraction and tensile strength analyses. The prepared PEC scaffolds showed a mean pore size of 130 μm, as revealed by SEM analysis, and a comparatively higher compressive strength. The findings of in vitro cytocompatibility, in vivo biocompatibility and osteogenic marker (genes/proteins) analysis suggest that the PECs blended at pH 7.0 showed greater stability and enhanced growth and an osteogenic differentiation capability of human mesenchymal stem cells (MSCs). To aid our understanding of protein–polyion binding mechanisms, we employed a molecular docking and simulation study of SF macrodomains and CS oligomer using Schrödinger 14 and GROMACS (Groningen Machine for Chemical Simulations) software. The study involved analytical techniques for macromolecular solution characterization and theoretical simulations based on molecular dynamics. The computational studies confirmed the presence of an integral RGD sequence that played a vital role in superior cell-attachment, proliferation and osteogenic differentiation of MSCs grown on the developed SF–CS PEC scaffolds.

Three Dimensional Honeycomb Patterned Fibrinogen Based Nanofibers Induce Substantial Osteogenic Response of Mesenchymal Stem Cells

Stem cells therapy offers a viable alternative for treatment of bone disorders to the conventional bone grafting. However clinical therapies are still hindered by the insufficient knowledge on the conditions that maximize stem cells differentiation. Hereby, we introduce a novel 3D honeycomb architecture scaffold that strongly support osteogenic differentiation of human adipose derived mesenchymal stem cells (ADMSCs). The scaffold is based on electrospun hybrid nanofibers consisting of poly (L-lactide ε-caprolactone) and fibrinogen (PLCL/FBG). Classical fibers orientations, random or aligned were also produced and studied for comparison. The overall morphology of ADMSC’s generally followed the nanofibers orientation and dimensionality developing regular focal adhesions and direction-dependent actin cytoskeleton bundles. However, there was an initial tendency for cells rounding on honeycomb scaffolds before ADMSCs formed a distinct bridging network. This specific cells organization appeared to have significant impact on the differentiation potential of ADMSCs towards osteogenic lineage, as indicated by the alkaline phosphatase production, calcium deposition and specific genes expression. Collectively, it was observed synergistic effect of nanofibers with honeycomb architecture on the behavior of ADMSCs entering osteogenic path of differentiation which outlines the potential benefits from insertion of such bioinspired geometrical cues within scaffolds for bone tissue engineering.

Ultrasound and lipid-coated microbubbles for osteogenic differentiation of mesenchymal stem cells in 3D printed tissue scaffolds

With increasing incidence of bone disorders in a rapidly aging, sedentary and overweight population, engineered bone tissues promise to be a better alternative for conventional bone grafts. However, bone tissue engineering currently suffers due to the inability to form mechanically strong porous structures that can be grown quickly. In this study, lipid-coated microbubbles (MB), traditionally used for contrast enhanced ultrasound imaging, were applied to harness the beneficial effects of ultrasound stimulation on proliferation and osteogenic differentiation of human mesenchymal stem cells (hMSCs) on 3D printed poly(lactic acid) (PLA) scaffolds. A significant increase in cell number was observed with low intensity pulsed ultrasound (LIPUS) treatment in the presence of MB after 1, 3, and 5 days of culture on scaffolds. Total protein content, alkaline phosphatase activity, and total calcium content were also found to increase with LIPUS with and without MB indicating enhancement in osteogenic differentiation...

A Viscoelastic Study of Poly(ε-Caprolactone) Microsphere Sintered Bone Tissue Engineering Scaffold

Tissue engineering scaffolds are intended as a replacement for conventional bone grafts used in the treatment of bone damages. One of the challenges in bone tissue engineering is to fabricate scaffolds with large pores, high porosity, and at the mean time proper mechanical properties suitable for bone applications. The elastic properties Young’s modulus and yield strength) of these scaffolds have been mostly considered but since bone is a viscoelastic material it is necessary to evaluate this behavior of the scaffolds as well. In the current study the novel method of microsphere sintering as a bottom-up approach was used to fabricate porous three dimensional (3D) bone scaffolds made of poly(e-caprolactone) with controlled properties. Different variables effective on the mechanical and architectural properties of the scaffold (including time and temperature of the sintering process) were investigated and the optimum conditions (100 min and 64.5 °C) to fabricate scaffolds with the highest possible mechanical properties and porosity were determined (Young’s modulus = 33.61 MPa, yield strength = 2.2 MPa, with 44.5% porosity). Then the viscoelastic properties of this scaffold was evaluated and studied using stress relaxation test (25% stress relaxation) and generalized Maxwell model and compared to bone. Based on these results, the highly interconnected scaffold showed proper mechanical properties, pore size and structure proper for bone tissue engineering.

Scaphoid nonunion: does open reduction, bone grafting and Herbert screw fixation justify the treatment?

Conventional bone grafting and Herbert screw fixation give satisfactory results for scaphoid nonunion; however, vascularized bone grafting has superior results, especially in the case of avascular necrosis of proximal fragment. Vascularized bone grafting is technically more demanding with small error of margin, problems of getting the appropriate graft, fixation and incorporation, and requires longer duration for wrist immobilization. Forty-five patients of scaphoid nonunion were treated by cancellous bone grafting, cortex containing graft if required and Herbert screw fixation. Functional outcomes were assessed at the latest follow up after surgery (minimum oneyear after surgery). The average pre-operative and post-operative scapho-lunate angle, grip strength, flexion-extension movement, radio-ulnar movement, scaphoid index and modified mayo score were improved from 49.60±6.40° (37-66) to 36.26±4.73° (range 28-46), 20.66±3.17kg (15-27) to 31.11±3.29kg (range 25-40), 78.57±14.22° (45-110) to 132.86±13.90° (100-165), 30.06±6.06° (20-44) to 44.95±6.37°(range 35-59), 0.66±0.076 (0.55-0.79) to 0.60±0.065 (range 0.49-0.73) and 58.66±5.24 (50-70) to 84.37±5.01 (range 75-95), respectively, with P value <0.001. Based on modified mayo score, 21 (46.7%) patients had excellent results, 19 (42.2%) had good results, 4 (8.9%) had fair results and one patient (2.2%) had poor results. Bone grafting and Herbert screw fixation provides a good option for treatment of scaphoid nonunion, especially in the absence of avascular necrosis of proximal fragment. More importantly, vascularized bone grafting in all scaphoid nonunion may not be necessary and could otherwise have been united uneventfully by this technique. However, avascular necrosis of proximal fragment must be ruled out pre-operatively as well as intra-operatively.

Biofabrication and Bone Tissue Regeneration: Cell Source, Approaches, and Challenges

The growing occurrence of bone disorders and the increase in aging population have resulted in the need for more effective therapies to meet this request. Bone tissue engineering strategies, by combining biomaterials, cells, and signaling factors, are seen as alternatives to conventional bone grafts for repairing or rebuilding bone defects. Indeed, skeletal tissue engineering has not yet achieved full translation into clinical practice because of several challenges. Bone biofabrication by additive manufacturing techniques may represent a possible solution, with its intrinsic capability for accuracy, reproducibility, and customization of scaffolds as well as cell and signaling molecule delivery. This review examines the existing research in bone biofabrication and the appropriate cells and factors selection for successful bone regeneration as well as limitations affecting these approaches. Challenges that need to be tackled with the highest priority are the obtainment of appropriate vascularized scaffolds with an accurate spatiotemporal biochemical and mechanical stimuli release, in order to improve osseointegration as well as osteogenesis.

Vascularized versus non-vascularized bone grafts in the treatment of scaphoid non-union

Conventional non-vascularized bone grafts as well as vascularized bone grafts are used to treat scaphoid non-union (SN). Due to limited available studies, the field of application using both grafts for SN still remains controversial. The aim of this study was to evaluate a treatment algorithm for the use of both vascularized versus non-vascularized bone grafts based on clinical outcomes and quality of life (QoL) to improve the level of evidence. Based on a retrospective cohort study, including 28 patients with vascularized and 45 patients with conventional bone grafts, functional parameters, radiological outcome, Mayo-wrist-score, and QoL by SF-36 were applied to statistically compare the outcome of these two techniques. Time between last procedure or trauma and study group scaphoid reconstruction was almost double in the vascularized bone grafting group. Comparable union rates were achieved with vascularized as well as non-vascularized bone grafts. Significant differences were observed between both groups for grip strength and radial-ulnar active range of motion. Further functional outcomes, radiological outcomes as well as QoL were found similar for both techniques in patients with surgical union. In order to achieve comparable and appropriate treatment results, vascularized bone grafts are recommended for patients with delayed treatment, impaired scaphoid vascularity, and revision surgery. Even in preselected, complex cases, the results are comparable to conventional grafts, which are the basis for further patient education and approve the powerful role of surgical angiogenesis of vascularized bone grafts.