Donor Bone Research Articles

Development of iPSC-derived human bone marrow organoid for autonomous hematopoiesis and patient-derived HSPC engraftment

Current efforts in translational studies in hematology often rely on immunodeficient mouse models for engrafting patient-derived hematopoietic stem and progenitor cells (HSPCs), yet these models often face challenges in effectively engrafting cells from patients with various diseases, such as myelodysplastic syndromes (MDS). In this study, we developed an induced pluripotent stem cell (iPSC)-derived human bone marrow organoid model that closely replicates the bone marrow microenvironment, facilitating the engraftment of MDS patient-derived HSPCs, thereby mirroring the patients' distinct disease characteristics. Specifically, through advanced microscopy, we verified the development of a complex three-dimensional network of endothelial, stromal, and hematopoietic cells within the organoids, resembling the autonomous human marrow microenvironment. Furthermore, we showed that HSPCs derived from the donor bone marrow of normal individuals or patients with MDS can migrate to and proliferate within the organoid’s vascular niche while maintaining self-renewal and original genetic profiles. Within the organoids, the differentiation patterns from MDS HSPCs were significantly distinct compared to the multilineage hematopoiesis from normal HSPCs, which can be correlated with the clinical manifestations of the disease. These findings underscore the significance of the organoid model in studying human hematopoiesis and the pathophysiology of hematologic diseases, offering new avenues for personalized medicine and therapeutic interventions.

Drain versus no-drain at the donor sites of iliac crest bone graft: a retrospective study

BackgroundClosed suction drainage is typically used in orthopaedic surgery to reduce the occurrence of incision complications. However, whether drainage tubes should be routinely placed in iliac crest bone graft surgeries is still unclear. This study aimed to evaluate the effect of closed suction drainage at iliac crest bone donor site on clinical prognosis.Materials and methodsG.Power was used for a prior analysis to estimate the required sample size. 91 patients with tibial plateau fractures who underwent iliac crest harvesting and grafting between January 2019 and January 2022 were enrolled in the study. All surgeries were performed by the same experienced surgeon team. Patients were divided into close suction drainage (CSD) group and no-CSD group according to the use of drainage tube. The demographic and perioperative data of the patients were collected and analyzed.ResultsThere were no significant differences in demographic characteristics between the two groups except that the CSD group had more people with diabetes. The use of closed suction drainage in patients undergoing iliac crest harvest can significantly reduce the incidence of incision complications without increasing pain level and extending hospital stay. However, the closed suction drainage obviously caused the increase of blood loss. More drainage tubes would cause more drainage fluid to flow out. And drainage tube placement may impose a higher financial burden on patients.ConclusionThe closed suction drainage should not be recommended routinely for iliac crest bone graft patients. Only when the patient is at high risk for infection and without severe blood loss, placing a single drainage tube is recommended.Trial registrationThis study was registered at (NCT04807062) and approved by the Ethics Committee of the participating institution (Theoretical No. 2015-003-1).

Elastic properties of 3D printed clavicles are closer to cadaveric bones of elderly donors than commercial synthetic bones

Synthetic bone models have increasing utility in orthopaedic research due to their low cost and low variability and have been shown to be biomechanically equivalent to human bones in a variety of ways. The rise in additive manufacturing (AM) for orthopaedic applications presents an opportunity to construct synthetic whole-bone models for biomechanical testing applications, but there is a lack of research comparing these AM models to cadaveric or commercially available bone surrogates. This study compares the mechanical properties of 3D printed clavicle models to commercially available (4th generation Sawbones) and human cadaveric clavicles via nondestructive cyclic 4-point bending, axial compression, and torsion, and a final axial compression test to failure. Commercially available synthetic clavicles had 57.8–203% higher superior-inferior bending rigidity (p < 0.0001), 80.9–198% higher axial stiffness (p < 0.001), and 314–557% higher torsional rigidity (p < 0.05) on average than AM and cadaveric clavicles. Cadaveric and AM clavicles printed from a BoneMatrix/VeroWhite composite material had similar failure mechanisms under axial compression while AM VeroWhite clavicles experienced catastrophic failure, but these groups did not have significantly different ultimate failure loads. Together, these results demonstrate that current commercially available synthetic clavicles may be too rigid to emulate the mechanical properties of elderly cadaveric clavicles, and that AM bone models can closely mimic these cadaveric bones in a variety of biomechanical loading schemes. These results show promising applications for future work using 3D printed bone surrogates for biomechanical analysis of orthopaedic implants and other surgical repair techniques.

Phase I/IIa Trial of Autologous Regulatory T Cell Therapy Together with Donor Bone Marrow Infusion in Kidney Transplantation

Phase I/IIa Trial of Autologous Regulatory T Cell Therapy Together with Donor Bone Marrow Infusion in Kidney Transplantation

Successful Allogeneic Hematopoietic Cell Transplantation for Patients with IL10RA Deficiency in Japan.

IL10RA (IL10 receptor subunit alpha) deficiency is an autosomal recessive disease that causes inflammatory bowel disease during early infancy. Its clinical course is often fatal and the only curative treatment is allogeneic hematopoietic cell transplantation (HCT). In Japan, only case reports are available, and there are no comprehensive reports of treatment outcomes. We retrospectively analyzed patients with IL10RA deficiency in Japan. Two newly identified and five previously reported patients were included in this study. Five patients underwent HCT; one untransplanted patient survived to age 14, and one died of influenza encephalopathy before transplantation. All five HCT recipients underwent HCT at the age before 2 years. They all were conditioned with fludarabine/busulfan- or fludarabine /melphalan-based regimens. The donor source was human leukocyte antigen haploidentical donor bone marrow (BM) for two patients and unrelated umbilical cord blood (CB) for two patients. One patient experienced graft failure with unrelated CB and required a second transplant with unrelated BM. All patients who underwent HCT survived and demonstrated an improved performance status. In cases of IL10RA deficiency, the need for transplantation should be promptly assessed, and early transplantation should be considered. (190/250).

361.9: Liver transplantation with delayed donor bone marrow transplantation in non-human primates achieves hematopoietic chimerism.

361.9: Liver transplantation with delayed donor bone marrow transplantation in non-human primates achieves hematopoietic chimerism.

Allogenic Vertebral Body Adherent Mesenchymal Stromal Cells Promote Muscle Recovery in Diabetic Mouse Model of Limb Ischemia

Chronic limb threatening ischemia (CLTI) carries a significant risk for amputation especially in diabetic patients with poor options for revascularization. Phase I trials have demonstrated efficacy of allogeneic mesenchymal stromal cells (MSC) in treating diabetic CLTI. Vertebral bone adherent mesenchymal stromal cells (vBA-MSC) are derived from vertebral bodies of deceased organ donors which offer the distinct advantage of providing a 1,000x greater yield compared to that of living donor bone aspiration. This study describes the effects of intramuscular injection of allogenic vBA-MSC in promoting limb perfusion and muscle recovery in a diabetic CLTI mouse model. A CLTI mouse model was created through unilateral ligation of the femoral artery in male polygenic diabetic TALLYHO mice. Treated mice were injected with vBA-MSC into the gracilis muscle of the ischemic limb 7 days post ligation. Gastrocnemius or tibialis muscle was assessed post-mortem for fibrosis by collagen staining, capillary density via immunohistochemistry, and mRNA by quantitative real time PCR. Laser Doppler perfusion imaging and plantar flexion muscle testing were performed to quantify changes in limb perfusion and muscle function. Compared to vehicle control, treated mice demonstrated indicators of muscle recovery including decreased fibrosis, increased perfusion, muscle torque, and angiogenesis. PCR analysis of muscle obtained 7- and 30-days post vBA-MSC injection showed an upregulation in expression of MyoD1 (p = 0.03) and MyH3 (p = 0.008) mRNA representing muscle regeneration, VEGF-A (p = 0.002 ; p = 0.004) signifying angiogenesis as well as IL-10 (p < 0.001), T regulatory cell marker Foxp3 (p = 0.04), and M2-biased macrophage marker Mrc1 (CD206) (p = 0.02). These findings indicate human allogeneic vBA-MSC ameliorate ischemic muscle damage and rescue muscle function. These results in a murine model will enable further studies to develop potential therapies for diabetic CLTI patients.

In vitro evaluation of mesenchymal stromal cell senescence

Mesenchymal stromal cells (MSCs) are adult multipotent stem cells that, for their immunomodulatory and reparative/anti-inflammatory properties, are a promising tool in cell therapy. For the treatment of patients, MSCs are in vitro stimulated to proliferate in a non-physiological condition and this situation could lead MSCs to malignant transformation. The clinical application of MSCs requires that the biosafety of these cells must be investigated. The cellular senescence is a crucial mechanism that prevents the growth of cells at risk for neoplastic transformation. The aim of this study was to investigate the capacity of healthy donor bone marrow derived MSCs to enter the senescence phase by evaluating the β-galactosidase activity. We tested 131 MSC batches after long-term in vitro culture, resulting positive for β-gal staining and showing a branched shape morphology typical of senescent cells. They displayed a progressive decline in proliferative capacity and none of them bypassed the senescence. In conclusions, our data indicate that MSCs are not inclined towards spontaneous neoplastic transformation. We believe that the control of MSC capacity to enter senescence is fundamental for quality and safety, considering the relevant interest in the MSC clinical applications.

Abstract Tu012: Innate Immune Pathway cGAS-STING in Macrophage Function in Atherosclerosis

Macrophages are key cells in atherosclerotic cardiovascular disease. Macrophages within a single plaque are heterogenous: some are lipid-laden “foam cells” with varying ability to recycle lipoproteins or clear dead cells while others secrete traditional “pro-inflammatory” signals. Determining what signals bias macrophages to one phenotype versus another could identify a therapeutic target. Our lab showed that after acute myocardial infarction, macrophages are skewed to a reparative phenotype by loss of cGAS-STING signaling. cGAS-STING are a pattern recognition receptor-adaptor pair that are activated by double stranded DNA in a sequence-independent manner. Global deletion of Sting and Cgas have been shown to protect against atherosclerosis in mice. We hypothesize that hematopoietic-specific loss of Cgas will reduce plaque burden by biasing macrophages to a less inflammatory phenotype and upregulating pro-resolving functions. To test this, B6.129S7- Ldlr tm1Her /J ( Ldlr -/-) mice (female, age 8-12 weeks, 9 per group) underwent total body irradiation followed by bone marrow transplant from C57BL6/N- Cgas -/- ( Cgas -/-) or wildtype donor mice (female, age 6-8 weeks). After bone marrow reconstitution, recipient mice were started on Western diet. Mice will continue Western diet for 12 weeks (through April 24, 2024). Then, aortas, peripheral blood, spleen, and bone marrow will be collected for further analysis including plaque burden, fibrous cap thickness, and macrophage phenotype. We will also perform in vitro studies using primary macrophages to determine how Cgas -/- affects macrophage effector functions critical for atherosclerosis. To date, mice that received Cgas -/- or wildtype donor bone marrow had similar baseline cell count, triglyceride and total cholesterol levels. Bone marrow derived macrophages (BMDM) from Cgas -/- mice have increased expression of fibronectin. Thus, at baseline Cgas -/- BMDM express high levels of a marker associated with pro-reparative macrophages. More studies are needed to characterize this phenotype and determine the consequence for in vivo atherosclerosis.

Donor site morbidity after scapula free flap surgery of head and neck reconstruction: A systematic review and meta-analysis.

The scapula free flap is becoming increasingly more utilized in head and neck reconstruction due to its natural geometry and soft tissue versatility. This study reviews the incidence rate, risk factors, and treatments of complications of scapula donor site morbidity. A review was performed for articles published between October 1990 and November 2022 in Medline (OVID), PubMed, Web of Science, and CENTRAL. After screening, 24 articles meeting the criteria were included. Overall, 660 head and neck surgeries with the scapula donor bone across 24 studies were included. Twenty studies of 612 scapula free flaps reported a pooled postoperative complication rate of 10.7%, with no major complications. Seven studies of 199 scapula reconstructions showed a mean Disability of Arm, Shoulder and Hand (DASH) score of 14.39/100. With its low rate of morbidity, the scapula flap presents itself as a good alternative for patients at risk for poor healing.

Bone autograft collapse. Clinical case of the complication and clinical case of the solutions to this problem

BACKGROUND: The issue of full-thickness osteochondral defect replacement in the talus is highly relevant. Bone autografting has proven effective in treating patients with this pathology, but the method has its drawbacks. The implantation of two or more bone autografts in large osteochondral defects may result in reduced contact strength between the donor bone and the recipient’s surrounding bone, leading to the formation of cysts and autograft instability. Clinical cases description: We present two clinical cases for your consideration. In the first case, chondroplasty of the talus was performed with mosaic implantation of bone autografts. Six months later, due to instability of the bone autograft accompanied by pain, ankle joint arthrodesis was performed. Six months postoperatively, the pain score on the VAS scale decreased from 7/10 to 3/10, the AOFAS score was 74/100, and the FAAM score was 70/84. In the second clinical case, a modified mosaic chondroplasty using AMIC technology with provisional fixation of bone autografts with a pin was performed. Six months later, CT scans showed osteointegration of the bone autografts without the formation of subchondral cysts. The questionnaires also demonstrated positive dynamics: the VAS score decreased from 7/10 to 1/10, the AOFAS score improved from 70/100 to 90/100, and the FAAM score increased from 72/100 to 83/84. CONCLUSION: The leading criterion for a successful bone autograft procedure is the stability of the autograft, which is achieved through adequate graft length and secure fixation. The proposed method of provisional fixation of the bone autograft with a pin during mosaic chondroplasty is a reproducible, effective, and cost-efficient technique that ensures the stability of the bone autograft and maintains its press-fit contact with the talus.

Biomechanical validation of novel polyurethane-resin synthetic osteoporotic femoral bones in axial compression, four-point bending and torsion

In addition to human donor bones, bone models made of synthetic materials are the gold standard substitutes for biomechanical testing of osteosyntheses. However, commercially available artificial bone models are not able to adequately reproduce the mechanical properties of human bone, especially not human osteoporotic bone.To overcome this issue, new types of polyurethane-based synthetic osteoporotic bone models have been developed. Its base materials for the cancellous bone portion and for the cortical portion have already been morphologically and mechanically validated against human bone. Thus, the aim of this study was to combine the two validated base materials for the two bone components to produce femur models with real human geometry, one with a hollow intramedullary canal and one with an intramedullary canal filled with synthetic cancellous bone, and mechanically validate them in comparison to fresh frozen human bone.These custom-made synthetic bone models were fabricated from a computer-tomography data set in a 2-step casting process to achieve not only the real geometry but also realistic cortical thicknesses of the femur. The synthetic bones were tested for axial compression, four-point bending in two planes, and torsion and validated against human osteoporotic bone.The results showed that the mechanical properties of the polyurethane-based synthetic bone models with hollow intramedullary canals are in the range of those of the human osteoporotic femur. Both, the femur models with the hollow and spongy-bone-filled intramedullary canal, showed no substantial differences in bending stiffness and axial compression stiffness compared to human osteoporotic bone. Torsional stiffnesses were slightly higher but within the range of human osteoporotic femurs.Concluding, this study shows that the innovative polyurethane-based femur models are comparable to human bones in terms of bending, axial compression, and torsional stiffness.

Application of autogenous block bone graft in the reconstruction of severe alveolar crest defect

Patients with severe alveolar ridge defects cannot be directly implanted and repaired, which seriously affects their quality of life. Onlay bone grafting is the main solution for severe alveolar ridge bone defect reconstruction, among which autogenous block bone grafting is the most widely used and is also the focus of clinical research on bone tissue reconstruction. This article expounds the characteristics and basic principles of autogenous bone block grafting, and comprehensively analyzes the selection of autogenous bone donor site, the principles of surgical operation, and the progress of bone graft techniques. In order to help surgeons make correct clinical decisions, increase the predictability of surgical effects, and improve the level of clinical diagnosis and treatment.

Degradation of the mechanical properties of cortical bone due to long duration storage

Understanding the behaviour and material properties of bone is critical in predicting the failure and fracture of bones in humans. To address this, mechanical tests have traditionally been conducted to characterize bone material and this has resulted in large body of literature. However, there appears to be a lack of complete information regarding the storage protocols used for bone specimens prior to conducting mechanical tests. For example, while storage methods are well described, parameters such as the time between donor death and bone retrieval, as well as time between specimen machining and testing, are seldom reported. As biological materials undergo degradation in storage after being removed from the donor, a clear understanding of this degradation behaviour would identify critical time frames in which previously stored cortical bone specimens should be tested such that they can still be considered representative of an in-vivo condition. In this paper, the results of an investigation to determine the effects of long duration storage on the measured mechanical properties of bovine cortical bone are reported. Three different storage protocols are compared; namely machined-refrigerated, machined-frozen and frozen-machined-frozen. Degradation effects are evident for both refrigerated and frozen specimens and the results demonstrate that testing bone specimens after more than one week in storage may not provide representative in-vivo properties. In addition, specimens exhibit severe degradation after six months in storage regardless of the storage protocol.

New finger reconstruction technologies using 3D printing

Introduction The use of 3D printing technology in finger reconstruction improves accuracy of the procedure minimizing the donor defect and optimizing the appearance and function of the finger. The use of this technology in the finger reconstruction with an osteocutaneous radial forearm flap with axial blood supply and lengthening of the digital stumps and metacarpals remains poorly explored.The objective of the study was to demonstrate new methods of preoperative planning for finger reconstruction and improve surgical outcomes.Material and methods Outcomes of five patients treated with original methods based on 3D technology were retrospectively evaluated during preoperative planning, reconstruction of the thumb using an osteocutaneous radial forearm flap with axial blood supply, relocation of the stump of the third finger and lengthening of the stumps of the first and second metacarpals. The patients could achieve consolidation of interpositional bone allografts following lengthening of the finger stumps, stability of the bone base of the finger, organotypic restructuring of the marginal allograft during plastic surgery with an osteocutaneous radial forearm flap, and a functional position of the reconstructed thumb using the middle finger stump.Results and discussion An individual device for planning finger reconstruction allows identification of the optimal size and position of the finger in three planes, which is essential for patients with severe hand deformities to avoid corrective procedures. An individual guide was used to osteotomize the radius to harvest a vascularized graft providing a cutout of a given size and shape and a cortical-cancellous allograft being identical in shape and size to replace the donor bone defect. The combined use of Masquelet technology and distraction of the finger stump or a metacarpal improved conditions for consolidation and restructuring of the interpositional allograft preventing fractures and infection.Conclusion The use of 3D technology in finger reconstruction using an osteocutaneous radial forearm flap with axial blood supply and distraction of the finger stumps and metacarpals can improve surgical outcomes.

RNA sequencing methods enable immune cell gene expression profiling and clonality determination

Abstract The adaptive immune system defends the human body from pathogens through B/T cell functions in various organs. Abnormality of these cells may reflect immunological disorder, presence of neoplastic tissue, or response to infectious agents. High-throughput sequencing technology has facilitated understanding gene expression and related cell functions. Still, an in-depth understanding of B and T cell phenotype and clonotype profiling is an emerging application that has yet to take full advantage of sequencing technology for disease diagnosis and prognosis. Here, we share results of RNA sequencing of immune system tissues, including healthy donor peripheral blood mononuclear cells (PBMC), lymph nodes, bone marrow, spleen, thyroid, thymus, and colon, as well as diseased PBMC and colon samples. Sequencing libraries were constructed and sequenced for B and T cell-specific gene expression and full-length immune repertoire profiling. We have identified tissue-specific B/T cell phenotype and clonality patterns related to tissue functions and disease progression. RNA-seq enables highly multiplex immunophenotyping and clonality determination for high-abundant clones that correlate with Immune-seq, with the latter targeted approach providing more in-depth clonality signatures. Integrating both RNA sequencing and immune repertoire sequencing approaches allows accurate phenotype and clonotype determination for the immune landscape in various tissues.

Abstract 102: Trained Immunity Impairs Inflammation Resolution And Dampens Efferocytosis

Chronic inflammation is a major driver of atherosclerotic cardiovascular disease, and therapeutics that target inflammation reduce clinical cardiac events beyond levels seen with conventional strategies targeting cholesterol alone. Recent findings suggest innate immune cells maintain ‘memory’ of prior exposure to inflammatory stimuli, a phenomenon known as ‘trained immunity’. In response to inflammatory stimuli, macrophages undergo metabolic and epigenetic rewiring that primes them to mount an augmented response upon a second exposure. Oxidized low-density lipoproteins (oxLDL) have recently been shown to be potent triggers of trained immunity. While trained immunity has been shown to promote inflammation, little is known about how immune training impacts efferocytosis. Therefore, we hypothesize that trained immunity in macrophages promotes inflammation by impairing efferocytosis. We treated murine bone marrow progenitors with oxLDL for 24 hours, then washed and differentiated them into macrophages (BMDMs). Upon assessing efferocytosis, trained BMDMs were able to ingest a first apoptotic cell (AC) better than untrained BMDMs yet had an impaired ability to take up additional ACs, reflecting a defect in continual efferocytosis. Using an in vivo approach, we transplanted donor bone marrow from Ldlr -/- mice fed a chow or Western diet into naïve C57BL/6 recipients. After recovery, we elicited peritoneal macrophages to assess efferocytosis and found that recipients receiving marrow from Western diet fed Ldlr -/- mice not only displayed impaired efferocytosis, but also significantly upregulated PGE 2 production, suggesting impaired resolution. To determine whether PGE 2 is a mediator of trained immunity, we primed bone marrow progenitors with PGE 2 and differentiated them into BMDMs. We found that macrophages primed with PGE 2 elaborated higher levels of inflammatory cytokines in response to LPS stimulation than controls. Overall, these findings demonstrate that oxLDL/Western diet-training impinges on the resolution program by impairing efferocytosis and are durable effects that demonstrate heritability. Future directions include determining the impact of these findings on the development of atherosclerosis.

To what extent can mastication functionality be restored following mandibular reconstruction surgery? A computer modeling approach

Statement of ProblemAdvanced cases of head and neck cancer involving the mandible often require surgical removal of diseased sections and subsequent replacement with donor bone. During the procedure, the surgeon must make decisions regarding which bones or tissues to resect. This requires balancing tradeoffs related to issues such as surgical access and post-operative function; however, the latter is often difficult to predict, especially given that long-term functionality also depends on the impact of post-operative rehabilitation programs. PurposeTo assist in surgical decision-making, we present an approach for estimating the effects of reconstruction on key aspects of post-operative mandible function. Material and MethodsWe develop dynamic biomechanical models of the reconstructed mandible considering different defect types and validate them using literature data. We use these models to estimate the degree of functionality that might be achieved following post-operative rehabilitation. ResultsWe find significant potential for restoring mandibular functionality, even in cases involving large defects. This entails an average trajectory error below 2 mm, bite force comparable to a healthy individual, improved condyle mobility, and a muscle activation change capped at a maximum of 20%. ConclusionThese results suggest significant potential for adaptability in the masticatory system and improved post-operative rehabilitation, leading to greater restoration of jaw function.

Complications of total-body irradiation in allogeneic bone marrow transplantation: A review article

Hematopoietic stem cell transplantation commonly known as bone marrow transplantation (BMT) or allogeneic BMT (using healthy blood stem cells from a donor) is the preferred therapeutic option for numerous blood-related conditions, both malignant and non-malignant. It is often the sole therapy strategy and essential for relapsed and refractory hematologic malignancies. There have studies regarding BMT on regimen containing total body irradiation (TBI) and a regimen without TBI. It is expected that TBI-based conditioning regimens provide better antitumor effects than chemotherapy regimens. The primary objective of TBI is to eradicate the recipient's bone marrow, facilitating the successful engraftment of donor bone marrow. Acute lymphoid leukemia (ALL) is the principal indication for TBI in bone marrow transplantation. Other diseases including Hodgkin’s lymphoma, chronic myeloid leukemia (CML), acute myeloid leukemia (AML), multiple myeloma (MM), etc., may benefit from TBI-based regimens; however, TBI use is associated with many side effects.The main complications of patients who underwent TBI-containing conditioning regimens in bone marrow transplantation are vomiting and nausea, with frequencies of approximately 66% and 35%, respectively. However, these events are easily managed. Acute complications include stomatitis, diarrhea, loss of appetite, temporary loss of taste, rash and asthenia. Moreover, veno-occlusive disease, interstitial pneumonitis, lung side effects, growth hormone deficiency, neurological side effects, cataracts, renal toxicity, endocrine impairments, and infertility are other complications in patients who underwent TBI-containing conditioning regimens in bone marrow transplantation. In review article, a complication of total-body irradiation in allogeneic bone marrow transplantation was assessed.

Use of Fibular Strut Graft for Reconstruction of Bone Defects

Introduction • Bone recalcitrant nonunion and bone defects usually follow trauma, resection of a malignant tumor of the musculoskeletal system and osteomyelitis. • Instead of amputation, which was used in the past, limb salvage surgeries, including non-vascularized or vascularized autografts and allografts, bone transport and replacement with prostheses are performed. • Among the above methods, nonvascularized autogenous bone graft use is an important treatment strategy that has been performed for over a hundred years. • The fibula is a tubular bone that has a suitable length, geometrical shape and mechanical strength and is considered to be the best donor bone for large bone defects. • Free vascularized fibular grafts achieve higher union rate than non-vascularized fibular grafts in the reconstruction of long bone defects. • In this study, 6 patients with bone defects treated by non-vascularized fibular grafts .We intended to assess the clinical outcomes of graft union, functional outcome.