Tibial Bone Defects Research Articles

Effect of glycoside of short-horned epimedium Herb on the expressions of transforming growth factor β 1 and basic fibroblast growth factor induced membrane by Masquelet technology

To observe the expressions of transforming growth factor β 1 (TGF-β 1) and basic fibroblast growth factor (bFGF) induced membrane by Masquelet technique in rats treated with glycoside of short-horned epimedium Herb, and to explore the effect of glycoside of short-horned epimedium Herb on Masquelet induced membrane. Sixty 3-month-old male Wistar rats were randomly divided into 3 groups with 20 rats in each group; a tibial bone defect (6 mm in length) model was established. The blank group (group A) was not treated; the control group (group B) and the experimental group (group C) were filled with vancomycin antibiotic bone cement in the drawing stage, and the bone cement was completely solidified. Group C was given perfused flavonoids glycoside of short-horned epimedium Herb (10 μmol/L) by gavage once a day (0.3 mL) from 1 day after operation, and groups A and B were given the same amount of normal saline by gavage. After operation, the recovery and wound healing of experimental animals were observed; at 4 weeks after operation, X-ray film was taken to observe the recovery of bone defect of proximal tibia; at 6 weeks after operation, the bone defect was observed, and the morphological changes and vascularization degree of granulation tissue and induction membrane tissue were observed; the expressions of TGF-β 1 and bFGF were observed by immunohistochemistry staining and ELISA detection. The bone defect models of the 3 groups were established successfully, and there was no abnormality after operation. The incisions healed by first intention after operation. At 4 weeks after operation, X-ray films of proximal tibial defect showed that there was obvious space in group A, while bone cement was filled and Kirschner wire fixation was good in groups B and C. At 6 weeks after operation, the gross observation showed that the granulation tissue was filled in the defect area in group A; transparent membrane was formed in groups B and C, and microvessels were seen in some areas, and the microvessels in group C were significantly more than those in group B. Immunohistochemical staining showed that the expressions of TGF-β 1 and bFGF were negative in group A, but they were expressed in groups B and C, and the expressions of TGF-β 1 and bFGF in group B were significantly less than those in group C. ELISA detection showed that the expressions of TGF-β 1 and bFGF in group C were significantly higher than those in groups A and B ( P<0.05), but there was no significant difference between groups A and B ( P>0.05). Glycoside of short-horned epimedium Herb can significantly increase the expressions of TGF-β 1 and bFGF, accelerate the process of osteogenesis, and contribute to bone shaping and reconstruction.

Use of porous custom-made cones for meta-diaphyseal bone defects reconstruction in knee revision surgery: a clinical and biomechanical analysis.

Although the practice of metaphyseal reconstruction has obtained successful clinical and radiological results in revision total knee surgery, off-the-shelf devices aren't an effective solution for all patients as they do not cover the full range of clinical possibilities. For this reason, during severe knee revisions, custom-made porous titanium cementless metaphyseal cones are nowadays employed as alternative to traditional surgeries. The aim of this study is to understand the benefits gained by the use of the custom-made cones against the performance of more traditional techniques, such as the use of cemented or cementless stems. Thus, a retrospective study on eleven patients and a biomechanical finite element analysis (FEA) was developed, based upon three clinical cases of the clinical analyzed cohort. Eleven patients underwent staged total knee arthroplasty revision with the use of 16 custom-made cones to correct severe femoral and tibial meta-diaphyseal bone defects. Clinical scores and range of movement were observed during the follow-up period (mean follow-up 26 ± 9.4months). Reason for surgery was periprosthetic joint infection (PJI) in eight patients and post-traumatic osteomyelitis in the other three patients. Three patients previously affected by PJI were selected among the eleven patients of the clinical population. For those patients, bone geometries and implants during surgery were replicated in silico and analyzed during different daily activities. For the same patients, as alternative solution for surgery, the use of cemented or cementless stems was also simulated by FEA. Stress patterns in different region of interest and risk of fracture in the bone were calculated and compared. No loosening, component migration, or mismatches between preoperative planning and intraoperative findings were clinically registered. Biomechanical results demonstrated that the use of custom-made cones induces a more homogeneously distributed bone stress than the other two techniques that concentrate the stress in spotted regions. The risk of fracture is comparable between the use of custom-made cones and cemented technique, while press-fit configurations increase the risk of fracture (more than 35%). Based upon the clinical evidence and the findings after the FEAs, the practice of porous custom-made metaphyseal cones in severe revisions of knee arthroplasties is showing promising biomechanical results. The homogeneous stresses distributions and the lower bone stress gradient could justify a reduction of bone fractures and the risk of implant loosening which could be the explanation to the successful clinical outcomes.

Deformity correction (upper tibial bone defect due to osteomyelitis) in lower limb using Ilizarov technique

Here we are presenting a massive bone defect of upper tibia and 7 cm limb length discrepancy due to long standing osteomyelitis, which was treated successfully using Ilizarov technique and frame.

Retraction of transporting bone segment during Ilizarov bone transport

BackgroundRetraction of transporting bone segment (TBS) may occur when the fixator of the TBS is removed prior to full consolidation of the distracted callus, which has adverse effect on the healing of the docking site. However, there are few reports on the retraction of TBS. The purpose of this study is to analyze the causes and risk factors of the retraction of TBS.MethodsThe clinical data of 37 cases with tibial bone defect treated by Ilizarov bone transport were analyzed retrospectively, in whom the TBS fixator was removed prior to full consolidation of the distracted callus and union of the docking site. Bivariate correlation was used to analyze relationship between the retraction distance of TBS and potential risk factors including age, gender, course, length of bone defect, number of operations, size of TBS, transport distance, timing and time interval of removal of TBS fixator. Risk factors with significant level were further identified using multivariate linear regression.ResultsBivariate correlation showed that the timing of removal was negatively correlated with the retraction distance, and the time interval and transport distance were positively correlated with the retraction distance(p < 0.05), the age, gender, course, length of bone defect, size of TBS and number of operations were not correlated with the retraction distance(p > 0.05). Multivariate linear regression of the 3 risk factors showed that the timing of removal and time interval were the main risk factors affecting the retraction distance (p < 0.05), but the transport distance was not (p > 0.05).ConclusionThe traction forces of TBS endured from the soft tissues and the unconsolidated distracted callus have elastic properties, which can make retraction of TBS. The timing of removal and time interval are the main risk factors of the retraction of TBS. In the case of early removal, another external fixation or quickly converted to internal fixation should be performed to avoid the adverse effect of more retraction.

Medium term clinical outcomes of tibial cones in revision knee arthroplasty.

Trabecular metal cones are a relatively new option for reconstruction of major bone defects during revision total knee arthroplasty (TKA). The purpose of the present study was to retrospectively assess medium-term results for tibial cones in revision TKA with a severe proximal tibial bone defect. We hypothesized that revision TKA patients with bone defects treated with trabecular metal cones have excellent medium-term clinical and radiological results. A single-center retrospective review included all consecutive cases of tibial revision using trabecular metal cones. All patients with a minimum 2-year follow-up were included in the study. There were no exclusion criteria. The primary endpoint was tibial cone survivorship. The secondary endpoints were revision TKA all-cause survivorship, patient-reported outcome measures with a Knee injury and Osteoarthritis Outcome Score (KOOS), SF 12, and radiographic analysis. Five of the 57 patients alive at last follow-up (8.77%) had undergone revision (4 for infection and 1 for instability). Complications comprised four cases (7.02%) of infection, 2 cases (3.51%) of tibial and femoral implant aseptic loosening that did not require revision surgery, 1 of which (1.75%) with associated patellar loosening, and 1 case (1.75%) of instability. Kaplan-Meier estimates showed 100% 5-year survivorship with tibial cone revision for aseptic loosening and 93.44% (95% CI 83.47-97.49%) for all-cause revision. The present study of cones used for tibial revision supports shows excellent results; however, longer and larger follow-up is needed to better assess results in revision TKA. 4, retrospective study.

Treatment of Tibial and Femoral Bone Defects With Bone Transport Over an Intramedullary Nail

To evaluate the results of the bone transport over an intramedullary nail (BTON) technique for the treatment of segmental bone defects. Retrospective review of case series. Level 1 trauma center. We included 40 patients who underwent reconstruction of the lower limb with BTON technique between 2000 and 2018. The technique was performed in the tibial segments in 21 patients and in the femoral segments in 19 patients. The surgical technique was performed in 2 stages for patients with infected nonunion. Infection was eradicated in all patients at the first stage. For the BTON at the second stage, monolateral external fixators and circular external fixators were used for femoral and tibial defects, respectively. In cases of defects without any infection, debridement with a single-stage BTON was performed. Complications as well as radiological and clinical results were evaluated according to the criteria of Paley-Maar. Minor complications occurred in 11 patients: pin site problems (9), cellulitis (1), and skin detachment due to Schanz screw (1). Major complications occurred in 8 patients: docking site nonunion (4), early consolidation and Schanz screw failure (1), knee flexion contracture (1), and ankle equinus contracture (2). Four patients had osteomyelitis as residual sequelae. Bone score was excellent in 27 patients. Excellent functional results were obtained in 31 patients. The BTON technique is associated with low cost because of the short treatment period, low complication risk, and rapid rehabilitation and is not limited by the amount of bone transport. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Graft Application and Dexamethasone Treatment Influences New Bone Formation in Rat Tibial Bone Defects

Graft Application and Dexamethasone Treatment Influences New Bone Formation in Rat Tibial Bone Defects

Biomechanical comparison between metal block and cement-screw techniques for the treatment of tibial bone defects in total knee arthroplasty based on finite element analysis

BackgroundManaging bone defects is a critical aspect of total knee arthroplasty. In this study, we compared the metal block and cement-screw techniques for the treatment of Anderson Orthopaedic Research Institute type 2A tibial bone defects from the biomechanical standpoint. MethodThe metal block and cement-screw techniques were applied to finite element models of 5- and 10-mm tibial bone defects. Biomechanical compatibility was evaluated based on the stress distributions of the proximal tibia and tibial tray. The displacement of the tibial tray and maximum relative micromotion between the tibial stem and tibia were analyzed to assess the stability of the implant. ResultsThe maximum stress in both the proximal tibia and tibial tray was greater with the cement-screw technique than with the metal block technique. The stress of the proximal lateral tibia with the cement-screw technique was significantly larger than with the metal block technique (p < 0.05). For the 5-mm bone defect, the maximum relative micromotion was lower than the critical value of 150 μm. For the 10-mm defect, the maximum relative micromotion was 128 μm with the metal block technique and 155 μm with the cement-screw technique, with the latter exceeding the critical value. ConclusionsThe cement-screw technique showed superior biomechanical compatibility to the metal block technique and is more suitable for 5-mm bone defects. However, as it may reduce the fixation strength in 10-mm bone defects, the metal block technique is more appropriate in this case.

Micromotion Analysis of Various Tibial Constructs in Moderate Tibial Defects in Revision Total Knee Arthroplasty

BackgroundThe purpose of this study is to compare the micromotion of various tibial reconstruction strategies including short cemented and long cementless stems with or without metaphyseal augmentation. MethodsA moderate tibial bone defect was milled into dual density polyurethane test blocks. Mechanical testing was performed on 4 test constructs: (1) short cemented stem (75-mm total length) alone; (2) short cemented stem with a symmetric metaphyseal cone; (3) a press-fit (175-mm total length) diaphyseal engaging tibial construct without a cone, and (4) the same press-fit tibial construct with a metaphyseal cone augment. Micromotion of the baseplate/cone construct with respect to the tibia block was measured during a stair descent loading profile for 10,000 cycles. The peak-to-peak micromotion of these various tibial constructs was compared. Unpaired t-tests were used to evaluate differences in peak-to-peak micromotion among the various tibial constructs tested. An analysis of variance was performed for final validation. ResultsThe cemented short stem demonstrated similar varus/valgus displacement, internal/external rotation, compression, and lift-off micromotion values under loading compared to a cementless long stem. A tibial cone improved compression and lift-off micromotion for both cemented and cementless constructs. A short 50-mm cemented stem with a cone demonstrated a lower micromotion at the anterior SI location compared to a press-fit 150-mm cementless stem without a tibial cone. ConclusionsA short cemented tibial component with a cone achieved similar micromotion during simulated stair descent compared to a cementless diaphyseal press-fit implant in cases of moderate tibial defects

Comparative Study between the Effect of Melatonin and Hyaluronic acid on Induced Bone Defect Healing in Rabbit

This study was aimed to highlight the individual effects of melatonin (MEL) and hyaluronic acid (HA)&#x0D; on bone healing and repair mechanism and to investigate a possible effect, for a topical application. New&#x0D; Zealand rabbits used in this study were divided into three groups for two healing intervals the experimental&#x0D; groups were: 1. Experimental groups (20 rabbits): all animals subjected to surgical operation in right tibia,&#x0D; creating bone defect 3mm in depth and 4mm in diameter filled with 0.1ml. Hyaluronic acid gel and left&#x0D; tibia bone defect filled with melatonin gel. 2. Control group (10 rabbits): induced bone defect on the right&#x0D; side only. Animals’ scarifications were done in 2 weeks and 4 weeks’ durations. Routine processing and&#x0D; sectioning technique was performed for histological evaluation. At the 2weeks healing interval, highest&#x0D; mean value of all measured parameters were recorded at melatonin group while at 4 weeks, there is high&#x0D; significant difference in all parameters; (p-value 0.000) among all control and experimental groups. A&#x0D; significant number of positive effects of MEL, as well as HA, as individual compounds on the bone healing&#x0D; regeneration.

Reconstruction of tibial metaphyseal defects with artificial components in revision arthroplasty (GenuX MK System)

Restoration of knee function by using tibial metaphyseal components in advanced metaphyseal bone defects after multiple bone-damaging revision surgery on the knee joint. Advanced tibial metaphyseal bone defects (Anderson Orthopaedic Research Institute [AORI] IIb andIII defects) in revision arthroplasty of the knee joint. Persistent or current joint infection, general infection (e.g., pneumonia), nonreconstructable insufficient extensor apparatus. Standard access including existing skin scars, arthrotomy, removal of cement spacer if necessary and removal of multiple tissue samples; preparation of femur first, followed by preparation of the tibia. Referencing the tibial rotation and joint line height. Tibial osteotomy referenced intramedullarily. Determination of the metaphyseal defect size and choice of component size. Positioning of the rasp guide for the preparation of the metaphyseal component (sleeve); gradual preparation of the bed for the metaphyseal component. Afterwards the prepared component at the desired depth (when using augments +5 or +10 mm accordingly 5 or 10 mm above the tibial plateau) is left and the tibial plateau is fixed on the embedded sleeve. Test coupling, control of the implant position and the height of the joint line radiologically. If satisfactory the definitive implants accordingly to the components of used implants before can be implanted. Full weight bearing. Regular wound control; limitation of the degree of flexion only with weakened or reconstructed extensor apparatus. Between May 2018 and August 2019, 14 metaphyseal tibial components were implanted in 14patients. The mean follow-up was 10.4 months. The follow-up included clinical examination, KSS (Knee Society Score) and an X‑ray and failure analysis. Asignificant improvement in range of movement from 75 ± 16° to 100 ± 14° (p < 0.01) was achieved. The KSS improved significantly from 78 ± 12points preoperatively to 137 ± 23points postoperatively. Two patients complained of persistent pain after exercise (walking distance >200 m) after 6months; tibial shaft pain was negated by all patients. The group examined afterwards showed an implant survival rate of 100% in the observation interval.

Osseointegration of titanium implants with a novel silver coating under dynamic loading.

Postoperative implant-associated infections are a severe complication in orthopaedics and trauma surgery. To address this problem, a novel implant coating was recently developed, which allows for the release of low concentrations of bactericidal silver. For an intended use on load-bearing endoprostheses, stable bone integration is required. The aim of the present study was to evaluate the biocompatibility and osseointegration of titanium implants with the novel coating in a mechanically loaded bone-defect model in sheep. Silver-coated devices were implanted into weight-bearing and non-weight-bearing tibial and femoral bone defects whereas, in the control group, uncoated titanium implants were inserted. The bony integration of the implants was assessed mechanically and histologically after 6 months. Silver concentrations were assessed in peripheral blood, liver, kidney and local draining lymph nodes as well as at the implantation site. After 6 months, shear strength at the interface and bone apposition to the implant surface were not significantly different between coated and uncoated devices. Mechanical loading reduced bony integration independently of the coating. Silver content at the implantation site was larger in the group with silver-coated implants, yet it remained below toxic levels and no cytotoxic side effects were observed. Concluding, the novel antibacterial silver coating did not negatively influence bone regeneration or implant integration under mechanically unloaded and even loaded conditions, suggesting that the silver coating might be suitable for orthopaedic load-bearing implants, including endoprostheses.

Management of Massive Tibial Bone Defect Using Unifocal Bone Transport with Ilizarov Apparatus: A case study

Introduction: Ilizarov technique is one of the excellent methods used for bony lengthening. The current literature states that the maximum possible amount of tibial lengthening by bifocal transport of an Ilizarov apparatus was 22 cm, while the maximum amount of tibial lengthening by unifocal transport of an Ilizarov apparatus was 14.5 cm.Case report: 40 years old Saudi teacher was presented with an open fracture at the right tibia of type 3B. The second debridement was done and ended up with 21.49 cm bone loss of the middle Tibial segment. Local flap plastic surgery was done to cover the skin defect and the bone transport was done at a rate of 1mm/day. The overall healing was excellent, and the patient returned to his pre-injury functional activity and rejoined his job as a teacher.Conclusion: Thus, the current case report is a unique new record of 21.49 cm of tibial lengthening achieved by the Ilizarov apparatus using unifocal transport. This will be a treatment hope for patients with excessive bone loss.

Injectable bone substitute based on chitosan with polyethylene glycol polymeric solution and biphasic calcium phosphate microspheres

We described a method to produce an injectable bone substitute consisting of a solid and liquid phase, this solid was formed using the coacervation method consisting of a mixture of Hydroxyapatite (HAp) and beta-Tricalcium Phosphate (β-TCP) which the sodium alginate - precursor - was removed during sinterization. The biphasic calcium phosphate microspheres had varying size distributions depending on the flow rate and these microspheres were mixed with a polymeric solution, chitosan and polyethylene glycol, and depending on the ratio of these phases, the injectability results varied. Nonetheless, the force required for complete removal will not disrupt the accuracy of injection into the bone defect while the biomaterial exhibited no cytotoxicity with promising results from in vivo using tibia bone defect in rabbits at 30 and 60 days whereas bone repair was more intense and accentuated with the usage of the biomaterial, and was gradually absorbed during the evaluated periods.

MiR-21 nanocapsules promoteearly bone repair of osteoporotic fractures by stimulating the osteogenic differentiation of bone marrow mesenchymal stem cells.

ObjectiveThe healing of osteoporotic fractures in the elderly patients is a difficult clinical problem. Currently, based on the internal fixation of fractures, the available drug treatments mainly focus on either inhibiting osteoclast function, such as bisphosphonate, calcitonin, oestrogen or promoting osteogenesis, such as parathyroid hormones. However, the availability of current antiosteoporotic drugs in promoting osteoporotic fracture healing is limited. The objective of the present study was to investigate the ability of the MiR-21/nanocapsule to enhance the early bone repair of osteoporotic fractures.MethodsBased on the presence of matrix metalloproteinases that are overexpressed at the fracture site, we designed the matrix metalloproteinase–sensitive nanocapsules which were formed by in situ free radical polymerisation on the surface of MiR-21 with 2-(methacryloyloxy) ethyl phosphorylcholine and the bisacryloylated VPLGVRTK peptide. The MiR-21/nanocapsule [n (miR-21)] and O-carboxymethyl chitosan (CMCS) were mixed until they formed a gel-like material [CMCS/n (miR-21)] with good fluidity and injectability. Thirty elderly Sprague Dawley (SD) rats (female, 14-month-old, 380 ± 10 g) were subjected to bilateral removal of the ovaries (ovariectomised). All rats were subjected to bilateral bone defects (2 mm diameter) of the proximal tibia and randomly divided into three groups (groups A, B, and C): separately injected with CMCS/n (miR-21), CMCS/n (NC-miR), and saline. Micro-computed tomography (CT) imaging was performed to evaluate newly formed bone volume and connectivity. Nondecalcified histology and toluidine blue staining were performed to measure the effects of CMCS/n (miR-21) on bone repair. In vitro, the effect of n (miR-21) on osteogenic differentiation to bone marrow mesenchymal stem cells (BMSCs) which derived from the ovariectomised rat model was observed.ResultsThe morphology of n (miR-21) was a regular spherical nanocapsule with a uniform small size (25–35 nm). The results confirmed that n (miR-21) could be efficiently phagocytosed by BMSCs and released in the cytoplasm to promote osteogenesis. The expression level of alkaline phosphatase and Runt-related transcription factor 2 mRNA in the n (miR-21) group was higher than that in the n (NC-miR) group. Animal experiments proved that CMCS/n (miR-21) produced better bone repair compared with the CMCS/n (NC-miR) group in the early stages of fracture healing at 4 weeks. In the late stage of fracture healing (8 weeks), micro-CT quantitative analysis showed that the new bone trabeculae in the CMCS/n (miR-21) group has decreased compared with the CMCS/n (NC-miR) group. In the CMCS/n (miR-21) group, the new cancellous bone had been absorbed, and the process of bone healing was almost completed. In contrast, the new bone in the CMCS/n (NC-miR) and the control groups was still in the healing process.ConclusionThe cytological tests confirmed that n (miR-21) can promote osteogenic differentiation of BMSCs derived from the osteoporosis rat model. Furthermore, the results of animal tests demonstrated that local injection of CMCS/n (miR-21) promoted the early healing of osteoporotic bone defects. Consequently CMCS/n (miR-21) promoted the bone repair process to enter the moulding phase earlier.The translational potential of this articleCMCS/n (miR-21) can be widely applied to elderly patients with osteoporotic fractures. This method can help patients with osteoporotic fractures recover earlier and avoid serious complications. It provides a potential approach for the clinical treatment of osteoporotic fractures in the elderly.

Age-Related Regeneration of Osteochondral and Tibial Defects by a Fibrin-Based Construct in vivo.

Tissue–biomaterial interactions in different microenvironments influence significantly the repair and regeneration outcomes when a scaffold or construct is implanted. In order to elucidate this issue, a fibrin gel filled macroporous fibrin scaffold (fibrin-based scaffold) was fabricated by loading fibrinogen via a negative pressure method, following with thrombin crosslinking. The macroporous fibrin scaffold exhibited a porous structure with porosity of (88.1 ± 1.3)%, and achieved a modulus of 19.8 ± 0.4 kPa at a wet state after fibrin gel filling, providing a suitable microenvironment for bone marrow-derived mesenchymal stem cells (BMSCs). The in vitro cellular culture revealed that the fibrin-based scaffold could support the adhesion, spreading, and proliferation of BMSCs in appropriate cell encapsulation concentrations. The fibrin-based scaffolds were then combined with BMSCs and lipofectamine/plasmid deoxyribonucleic acid (DNA) encoding mouse-transforming growth factor β1 (pDNA-TGF-β1) complexes to obtain the fibrin-based constructs, which were implanted into osteochondral and tibial defects at young adult rabbits (3 months old) and aged adult rabbits (12 months old) to evaluate their respective repair effects. Partial repair of osteochondral defects and perfect restoration of tibial defects were realized at 18 weeks post-surgery for the young adult rabbits, whereas only partial repair of subchondral bone and tibial bone defects were found at the same time for the aged adult rabbits, confirming the adaptability of the fibrin-based constructs to the different tissue microenvironments by tissue-biomaterial interplays.

Bone reconstruction by the induced membrane technique. What differences between conventional and ballistic trauma?

BackgroundThe induced membrane technique (IMT) has been widely evaluated for reconstruction of post-traumatic bone defects. However, no specific evaluation was conducted in ballistic injuries. The objective of the present study was to compare IMT in conventional trauma (CT) versus ballistic trauma (BT) managed in a military trauma center. MethodsA retrospective study was conducted between 2009 and 2018 in patients treated by IMT for post-traumatic bone defects, whatever the defect location. Endpoints comprised bone union, residual infection, additional bone grafting and lower-limb amputation. ResultsThirty-six patients were included: 24 in the CT and 12 in the BT group. Demographics and injury pattern were similar in both groups, with open fracture and infected lesions predominating. The only significant difference was that tibial bone defects were larger in the BT group. Operative parameters and results were also similar. At a mean 24 months’ follow-up, bone union rate was 83% in both groups, without significant differences in residual infection, complementary grafting or late amputation. ConclusionIMT is appropriate to bone reconstruction in the aftermath of ballistic trauma, with similar results to those obtained in conventional trauma. Level of evidenceIV, retrospective study.

Electrospun Icariin-Loaded Core-Shell Collagen, Polycaprolactone, Hydroxyapatite Composite Scaffolds for the Repair of Rabbit Tibia Bone Defects.

BackgroundElectrospinning is a widely used technology that can produce scaffolds with high porosity and surface area for bone regeneration. However, the small pore sizes in electrospun scaffolds constrain cell growth and tissue-ingrowth. In this study, novel drug-loading core-shell scaffolds were fabricated via electrospinning and freeze drying to facilitate the repair of tibia bone defects in rabbit models.Materials and MethodsThe collagen core scaffolds were freeze-dried containing icariin (ICA)-loaded chitosan microspheres. The shell scaffolds were electrospun using collagen, polycaprolactone and hydroxyapatite materials to form CPH composite scaffolds with the ones containing ICA microspheres named CPHI. The core-shell scaffolds were then cross-linked by genipin. The morphology, microstructure, physical and mechanical properties of the scaffolds were assessed. Rat marrow mesenchymal stem cells from the wistar rat were cultured with the scaffolds. The cell adhesion and proliferation were analysed. Adult rabbit models with tibial plateau defects were used to evaluate the performance of these scaffolds in repairing the bone defects over 4 to 12 weeks.ResultsThe results reveal that the novel drug-loading core-shell scaffolds were successfully fabricated, which showed good physical and chemical properties and appropriate mechanical properties. Furthermore, excellent cells attachment was observed on the CPHI scaffolds. The results from radiography, micro-computed tomography, histological and immunohistochemical analysis demonstrated that abundant new bones were formed on the CPHI scaffolds.ConclusionThese new core-shell composite scaffolds have great potential for bone tissue engineering applications and may lead to effective bone regeneration and repair.

A finite element analysis of tibial tritanium cones without stems in varying bone defects

BackgroundIn the UK around 10% of hip and knee arthroplasties are revision operations. At revision total knee arthroplasty (rTKA), bone loss management is critical to achieving a stable bone-implant construct. Though tritanium cones have been used to manage bone defects in rTKA, their biomechanical performance with varying defects remains unknown. MethodsUncontained tibial bone defects at four anatomic locations, with varying depths and widths (Type T2A and T2B) were investigated computationally in a composite tibia which was subjected to four loading scenarios. The ability of the tritanium cone to replace the tibial bone defect was examined using the outcome measures of bone strain distribution and interface micromotions. ResultsIt was found that anterior and lateral defects do not significantly alter the strain distribution compared with intact bone. For medial defects, strain distribution is sensitive to defect width; while strain distributions for posterior defects are associated with defect width and depth. In general, micromotions at the bone-implant interface are small and are primarily influenced by defect depth. ConclusionsOur models show that the cone is an acceptable choice for bone defect management in rTKA. Since all observed micromotions were small, successful osteointegration would be expected in all types of uncontained defects considered in this study. Tritanium cones safely accommodate uncontained tibial defects up to 10 mm deep and extending up to 9 mm from the centre of the cone. Medial and posteriorly based defects managed with symmetric cones display the greatest bone strains and asymmetric cones may be useful in this context.

Evaluation of the In Vivo Biological Effects of Marine Collagen and Hydroxyapatite Composite in a Tibial Bone Defect Model in Rats.

One of the most promising strategies to improve the biological performance of bone grafts is the combination of different biomaterials. In this context, the aim of this study was to evaluate the effects of the incorporation of marine spongin (SPG) into Hydroxyapatite (HA) for bone tissue engineering proposals. The hypothesis of the current study is that SPG into HA would improve the biocompatibility of material and would have a positive stimulus into bone formation. Thus, HA and HA/SPG materials were produced and scanning electron microscopy (SEM) analysis was performed to characterize the samples. Also, in order to evaluate the in vivo tissue response, samples were implanted into a tibial bone defect in rats. Histopathological, immunohistochemistry, and biomechanical analyses were performed after 2 and 6weeks of implantation to investigate the effects of the material on bone repair. The histological analysis demonstrated that composite presented an accelerated material degradation and enhanced newly bone formation. Additionally, histomorphometry analysis showed higher values of %BV/TV and N.Ob/T.Ar for HA/SPG. Runx-2 immunolabeling was higher for the composite group and no difference was found for VEGF. Moreover, the biomechanical analysis demonstrated similar values for all groups. These results indicated the potential of SPG to be used as an additive to HA to improve the biological performance for bone regeneration applications. However, further long-term studies should be carried out to provide additional information regarding the material degradation and bone regeneration.