Reconstruction Of Large Bone Defects Research Articles

An Elastin-derived composite matrix for enhanced vascularized and innervated bone tissue reconstruction: from material development to preclinical evaluation.

Despite progress in bone tissue engineering, reconstruction of large bone defects remains an important clinical challenge. Here, we developed a biomaterial designed to recruit bone cells, endothelial cells, and neuronal fibers within the same matrix, enabling bone tissue regeneration. The bioactive matrix is based on modified elastin-like polypeptides (ELPs) grafted with laminin-derived adhesion peptides IKVAV and YIGSR, and the SNA15 peptide for retention of hydroxyapatite (HA) particles. The composite matrix shows suitable porosity, interconnectivity, biocompatibility for endothelial cells, and the ability to support neurites outgrowth by sensory neurons. Subcutaneous implantation led to the formation of osteoid tissue, characterized by the presence of bone cells, vascular networks, and neuronal structures, while minimizing inflammation. Using a rat femoral condyle defect model, we performed longitudinal micro-CT analysis, which demonstrates a significant increase in the volume of mineralized tissue when using the ELP-based matrix compared to empty defects and a commercially available control (Collapat). Furthermore, visible blood vessel networks and nerve fibers are observed within the lesions after a period of two weeks. By incorporating multiple key components that support cell growth, mineralization, and tissue integration, this ELP-based composite matrix provides a holistic and versatile solution to enhance bone tissue regeneration. This article is protected by copyright. All rights reserved.

Indications for Nonbiological Reconstruction of Posttraumatic Bone Defects About the Knee.

3D printing and modeling has continued to grow in popularity over the past decade because the technology has matured and become more affordable and widely available. The main indications for nonbiological reconstruction of large bone defects are principally those patients where the candidate is unlikely to be successful if reconstructed by other means. Bespoke, custom, patient-specific implants can be designed to very effectively address bone loss, incorporating design elements that are particular to the needs of any given unique clinical condition. These implants are generally designed as titanium scaffolds that encourage bony incorporation at the host implant junction both proximal and distal. These scaffolds are typically considered a cellular solid, with high porosity that also promotes bone ingrowth directly into the substance of the body of the implant. Titanium scaffolds of this type have become a useful treatment alternative for large segmental bone defects around the knee, especially distal femoral defects. These are often adult patients with local or systemic compromise, or instead they may be too young to be considered candidates for reconstruction using a megaprosthesis. The process requires careful evaluation of individual patients, then matching that patient with the best treatment option, while recognizing the expectations and demands specific to that particular patient. Several cases are presented here to illustrate the variety of indications that can be successfully addressed with this technology, highlighting the quality of the clinical outcome that can be achieved despite the complexity of the pathology encountered.

Midterm Donor Site Morbidity After Vascularized Free Fibula Flap Harvesting.

Vascularized fibula grafts (VFGs) have become one of the most preferred grafts for the reconstruction of bone defects. However, despite the many advantages over other graft options, recipient and donor site morbidities are also common. Donor site morbidity has been reported at rates ranging from 5% to 67%. The aim of this study was to present a single-center series examining the clinical, functional, and radiologic aspects of donor site morbidity following VFG harvesting. The study included 69 patients who underwent biological reconstruction with VFG for bone tumors, avascular necrosis of the femoral head, or bone defects after trauma. Patients were evaluated functionally, clinically, and radiologically for donor site morbidity. Donor site morbidity was observed in 33 of 69 patients (48%). The most complications were sensation deficits around the feet and ankles (20 of 69; 29%). Knee laxity was more common in patients who underwent osteoarticular fibular resection (P = .006). We found VFG to be an effective method for the reconstruction of large bone defects, but associated with a relatively high rate of complications. Complications requiring surgical intervention were rare and the majority of patients did not have long-term functional limitations. Level IV, retrospective case series.

Polydioxanone Enhances Bone Regeneration After Resection and Reconstruction of Rat Femur with rhBMP2.

The aim of this study was to assess the bone regeneration potential of a polydioxanone (PDO) scaffold together with recombinant human bone morphogenetic protein-2 (rhBMP-2) for the reconstruction of large bone defect. In total, 24 male rats (6 months old) were subjected to bilateral femoral stabilization using titanium plates to create a 2 mm gap, and reconstruction using rhBMP-2 (Infuse®; 3.25 μg). The bone defects were covered with PDO (PDO group), or with titanium mesh (Ti group). Animals were euthanized on days 14 and 60. Simultaneously, 16 rats received PDO and Ti in their dorsum for the purpose of biocompatibility analysis at 3, 5, 7, and 10 days postoperatively. X-ray densitometry showed a higher density in the PDO group on day 14. On day 60, coverage of the bone defect with PDO showed a larger quantity of newly formed bone than that found for the Ti group, a lower inflammatory infiltrate value, and a more significant number of blood vessels on day 14. By immunohistochemical assessment, runt-related transcription factor 2 (RUNX2) and osteocalcin (OCN) showed higher labeling on day 14 in the PDO group. On day 60, bone morphogenetic protein-2 (BMP-2) showed higher labeling in the PDO group, whereas Ti showed higher labeling for osteoprotegerin, nuclear factor kappa B ligand-activating receptor, RUNX2, and OCN. Furthermore, biocompatibility analysis showed a higher inflammatory response in the Ti group. The PDO scaffold enhanced bone regeneration when associated with rhBMP-2 in rat femur reconstruction. Impact statement Regeneration of segmental bone defects is a difficult task, and several techniques and materials have been used. Recent advances in the production of synthetic polymers, such as polydioxanone (PDO), produced by three-dimensional printing, have shown distinct characteristics that could improve tissue regeneration even in an important bone defect. The present preclinical study showed that PDO membranes used as scaffolds to carry recombinant human bone morphogenetic protein-2 (rhBMP-2) improved bone tissue regeneration by more than 8-fold when compared with titanium mesh, suggesting that PDO membranes could be a feasible and useful material for use in guided bone regeneration. (In English, viable is only used for living creatures capable of sustaining life.

[Translated article] Mechanical resistance of polylactic acid bone matrices developed by 3D printing for the reconstruction of bone defects

IntroductionBone defects are one of the main limitations in orthopaedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodelling. Material and methodsA new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modelling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined. ResultsThe filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behaviour. ConclusionsThe new methodology allows the creation of personalised neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.

Use of dual mobility cup cemented into a tantalum acetabular shell for hip revision with large bone loss can decrease dislocation risk without increasing the risk of mechanical failure

BackgroundPorous tantalum components and augments have demonstrated short to midterm fixation stability in acetabular total hip arthroplasty (THA) revision but do not offer a novel option to decrease the postoperative dislocation rate. Recently, dual mobility (DM) cups have gained interest to decrease the prevalence of recurrent hip instability after revision hip arthroplasty, but this issue was not confirmed combined with use of tantalum reconstruction devices. Therefore, we did a retrospective study aiming to: (1) evaluate at a 5-year minimum follow-up period the dislocation rate (and other intra- and postoperative complications), (2) assess radiographic results specifically looking at osseointegration and restoration of the hip center, (3) and also clinical results in a cohort of patients who underwent complex acetabular reconstruction with trabecular metal revision components associated with a cemented DM socket. HypothesisUsing a DM socket cemented in porous tantalum components can reach the low risk of hip dislocation reported with DM components in revision setting without increasing the risk of a mechanical failure. MethodsA cross-sectional study identified 174 THA revision including an acetabular revision. Were excluded 118 revisions with acetabular defects Type 1, 2a or 2B according to Paprosky's classification, as well as 18 hips revised without a dual mobility and 3 patients (3 hips) lost to follow-up. Were thus included in this study 35 hips (35 patients) implanted with uncemented total hip arthroplasty revision using both trabecular metal acetabular cup-cage reconstruction and a cemented DM cup. Seven hips were classified Paprosky types 2C, 15 type 3A and 13 types 3B. Patients were followed with clinical and radiological evaluation regarding dislocation rate, infection, reoperation or re-revision, osseointegration and restoration of the hip center, and functional results according to the Harris hip score and psoas impingement presence. ResultsAt a mean follow-up of 8.1±1.8 years (5.1–12.6), one dislocation was recorded, and one acute deep infection. No patient required a cup re-revision for septic or aseptic loosening. The survivorship at 8years regarding revision for any cause as an endpoint was 96.5% (CI95%: 92–99). Osseointegration of TM implants was analyzed and found no acetabular migration at the last follow-up in the cohort. The mean hip center position was optimized from 48±7mm (37–58) to 34±5mm (29–39) vertically and from 26±5mm (–18–36) to 24±8mm (7–31) horizontally without reaching significance (p=0.1). On the last follow-up X-rays, the mean acetabular inclination was 47̊±9̊ (32̊–61̊). According to the criteria of Hirakawa, 97.1% (34/35) of the hip centers were restored. One cup (2.9%) was more than 5mm proximally from the hip center, and none more than 10mm. Clinical results assessed a Harris Hip Score improved from 36±17 (23–62) preoperatively to 82±15 (69–93) at last follow-up (p<0.0001). Two patients (2/35, 5.7%) complained of psoas impingement. ConclusionThis study suggests effectiveness of DM cups in association with a tantalum-made acetabular shell for reconstruction of large bone defect in THRs for both solving postoperative instability and aseptic loosening without increasing the re-revision rate for any reason in a midterm follow-up. Level of evidenceIV; observational study.

Black phosphorus-incorporated novel Ti-12Mo-10Zr implant for multimodal treatment of osteosarcoma.

The repair and reconstruction of large bone defects after bone tumor resection is still a great clinical challenge. At present, orthopedic implant reconstruction is the mainstream treatment for repairing bone defects. However, according to clinical feedback, local tumor recurrence and nonunion of bone graft are common reasons leading to the failure of bone defect repair and reconstruction after bone tumor resection, which seriously threaten the physical and mental health of patients. On this basis, here the self-developed low modulus Ti-12Mo-10Zr alloy (TMZ) was chosen as substrate material. To improve its biological activity and osteointegration, calcium, oxygen, and phosphorus co-doped microporous coating was prepared on TMZ alloy by microarc oxidation (MAO). Then, black phosphorus (BP) nanosheets were incorporated onto MAO treated TMZ alloy to obtain multifunctional composites. The obtained BP-MAO-TMZ implant exhibited excellent photothermal effects and effective ablation of osteosarcoma cancer cells under the irradiation of 808nm near infrared laser, while no photothermal or therapeutic effects were observed for TMZ alloy. Meanwhile, the structure/component bionic coating obtained after MAO treatment as well as the P-driven in situ biomineralization performance after incorporation of BP nanosheets endowed BP-MAO-TMZ implant with synergistic promoting effect on MC3T3-E1 osteoblasts' activity, proliferation and differentiation ability. This study is expected to provide effective clinical solutions for problems of difficult bone regeneration and tumor recurrence after tumor resection in patients with bone tumors and to solve a series of medical problems such as poor prognosis and poor postoperative quality of patients life with malignant bone tumors.

High Risk for Persistent Peri-Prosthetic Infection and Amputation in Mega-Prosthesis Reconstruction.

A peri-prosthetic joint infection is a feared complication after mega-prosthesis reconstruction of large bone defects. The current study investigates how patients operated with a mega-prosthesis due to sarcoma, metastasis, or trauma, are affected by a deep infection focusing on re-operations, risk for persistent infection, arthrodesis, or subsequent amputation. Time to infection, causative bacterial strains, mode of treatment and length of hospital stay are also reported. A total of 114 patients with 116 prostheses were evaluated, a median of 7.6 years (range 3.8-13.7) after surgery, of which 35 (30%) were re-operated due to a peri-prosthetic infection. Of the infected patients, the prosthesis was still in place in 51%, 37% were amputated, and 9% had an arthrodesis. The infection was persistent in 26% of the infected patients at follow-up. The mean total length of hospital stay was 68 (median 60) days and the mean number of reoperations was 8.9 (median 6.0). The mean length of antibiotic treatment was 340 days (median 183). Coagulase-negative staphylococci and Staphylococcus aureus were the most frequent bacterial agents isolated in deep cultures. No MRSA- or ESBL-producing Enterobacterales were found but vancomycin-resistant Enterococcus faecium was isolated in one patient. In summary, there is a high risk for peri-prosthetic infection in mega-prostheses, resulting in persistent infection or amputation relatively often.

LncRNA HOTAIRM1 promotes dental follicle stem cell-mediated bone regeneration by regulating HIF-1α/KDM6/EZH2/H3K27me3 axis.

Large bone defect reconstruction undergoes hypoxia and remains a major practical challenge. Bone tissue engineering with a more promising stem cell source facilitates the development of better therapeutic outcomes. Human dental follicle stem cells (hDFSCs) with superior multipotency, osteogenic capacity, and accessibility have been proven a promising cell source for bone regeneration. We previously identified a novel long noncoding RNA (lncRNA), HOTAIRM1, to be highly expressed in hDFSCs. Here we found that HOTAIRM1 overexpressed hDFSCs promoted bone regeneration in rat critical-size calvarial defect model. Mechanically, HOTAIRM1 was induced in hDFSCs under hypoxic conditions and activated HIF-1α. RNA-sequencing analysis indicated that HOTAIRM1 upregulated oxygen-sensing histone demethylases KDM6A/B and suppressed methyltransferase EZH2 via targeting HIF-1α. The osteogenic differentiation of hDFSCs was accompanied with demethylation of H3K27, and HOTAIRM1 overexpression decreased the distribution of H3K27me3 in osteogenic genes, including ALP, M-CSF, Wnt-3a, Wnt-5a, Wnt-7a, and β-catenin, thus promoted their transcription. Our study provided evidence that HOTAIRM1 upregulated KDM6A/B and inhibited EZH2 in a HIF-1α dependent manner to enhance the osteogenesis of hDFSCs. HOTAIRM1-mediated hDFSCs may serve as a promising therapeutic approach to promote bone regeneration in clinical practice.

Engineering mussel-inspired multifunctional nanocomposite hydrogels to orchestrate osteoimmune microenvironment and promote bone healing

The reconstruction of large bone defects by bioactive materials without exogenous cells, cytokines or growth factors remains a substantial clinical challenge. Herein, we present the rational design of injectable and adhesive (GMAD/LP) hydrogels composed of gelatin-methacryloyl (GelMA), dopamine-grafted alginate (AD), and polydopamine-functionalized Laponite (Lap@PDA) nanosheets that can act as osteoimmune regulators to engineer the pro-regenerative microenvironment for personalized bone regeneration. The as-fabricated GMAD/LP hydrogel with excellent tissue adhesion, self-healing, injectability, and improved mechanical strength can fill irregular bone defects in a minimally invasive manner. Moreover, the hydrogel exhibited outstanding osteogenic potential and osteoimmunomodulatory functions in vitro, significantly promoting the adhesion, proliferation, spreading, and osteogenic differentiation of bone mesenchymal stem cells (BMSCs), which was further augmented by hydrogel-induced macrophage M2-phenotype polarization and effective M2 macrophage-BMSC crosstalk. In vivo experiments in a cranial defect model demonstrated that the GMAD/LP hydrogel induced a reparative microenvironment similar to that in normal cranium, as characterized by an increased percentage of anti-inflammatory M2 macrophages and endogenous stem cells and high-level neovascularization, consequently accelerating bone healing. This strategy not only achieves a bioactive hydrogel for bone defect reconstruction but also provides a feasible methodology to recover injured bone tissue through integrated design with diverse functions.

Resistencia mecánica de matrices óseas de ácido poliláctico desarrolladas por impresión 3D para la reconstrucción de defectos óseos

IntroductionBone defects are one of the main limitations in orthopedic surgery and traumatology. For this reason, multiple bone replacement systems have been developed, either by prosthetic implant or by substitution with osteoforming substances, whose limitations are their survival and lack of structurality, respectively. The objective of this work is the generation of a new material for the creation of biologically active structures that have sufficient tensile strength to maintain the structure during remodeling. Material and methodsA new filament based on the fusion of natural polylactide acid (PLA) powder was designed for the generation of pieces by means of fused deposition modeling (FDM) on which to carry out tensile mechanical tests of osteosynthesis material. A total of 13 groups with different cortical thickness, filling and layer height were carried out, with 10 tensile tests in each group, defining the tensile breaking limit for each group. The regression lines for each group and their mechanical resistance to traction on the filament used were determined. ResultsThe filament ratio per contact surface unit with the osteosynthesis used was the main determinant of the mechanical resistance to traction, either at the expense of the increase in cortical thickness or by the increase in the percentage of cancellous bone filling. Layer height had a minor effect on tensile strength. The regression value was high for cortical thickness and cancellous filling, being elements with a predictable biomechanical behavior. ConclusionsThe new methodology allows the creation of personalized neutral and implantable PLA bone matrices for the reconstruction of large bone defects by means of 3D printing by FDM with a mechanical resistance to traction greater than that of current biological support structures.

Biological reconstruction of large bone defects : Masquelet technique and new procedures

Extensive diaphyseal and metaphyseal bone defects continue to pose amajor challenge for orthopedic trauma surgeons. Various treatment options have been described for the biological reconstruction of these defects. The most frequently used methods are bone segment transport, the Masquelet technique and 3D printed scaffolds. As far as the Masquelet technique is concerned, in the first stage spacers, such as polymethyl methacrylate (PMMA), calcium sulfate or polypropylene are inserted into the bone defects to induce a foreign body membrane. In the second stage the bone defect surrounded by the induced membrane is filled with autologous cancellous bone. The time interval between the first and second interventions is usually 4-8weeks whereby the induced membranes do not lose their bioactivity even with alatency period longer than 8weeks. Three-dimensional printed scaffolds are increasingly used but large clinical studies are lacking in order to show the exact role of this procedure in the reconstruction of bone defects.

Application of three-dimensional printed customized prosthesis with preserved epiphysis and articular surface in the reconstruction of large bone defects in treatment of adolescent femoral malignant tumors

To investigate the clinical application and effectiveness of three-dimensional (3D) printed customized prosthesis with preserved epiphysis and articular surface in the reconstruction of large bone defects in treatment of adolescent femoral malignant tumors. The clinical data of 10 adolescent patients with femoral primary malignant tumor who met the selection criteria and underwent limb salvage surgery with 3D printed customized prosthesis with preserved epiphysis and articular surface between January 2020 and October 2021 were retrospectively analyzed. There were 6 males and 4 females with an average age of 12.5 years ranging from 7 to 18 years. There were 8 cases of osteosarcoma and 2 cases of Ewing's sarcoma. Enneking stage was Ⅱb. The length of the lesions ranged from 76 to 240 mm, with an average of 138.0 mm. The length of osteotomy (i. e. length of customized prosthesis) ranged from 130 to 275 mm, with an average of 198.5 mm; the distance between distal osteotomy end and epiphyseal line ranged from 0 to 15 mm, with an average of 8.8 mm; the bone defect after osteotomy accounted for 37.36% to 79.02% of the total length of the lesion bone, with a mean of 49.43%. The operation time, intraoperative blood loss, complications, tumor outcome (refered to RESIST1.1 solid tumor efficacy evaluation criteria), and limb length discrepancy were recorded. The Musculoskeletal Cancer Society (MSTS) 93 score was used to evaluate the function at 6 months after operation, and visual analogue scale (VAS) score was used to evaluate the pain before and after operation. The operation was successfully performed in all the 10 patients, and the postoperative pathological results were consistent with the preoperative pathological results. The operation time was 165-440 minutes, with an average of 263 minutes; and the intraoperative blood loss was 100-800 mL, with an average of 350 mL. All patients were followed up 7-26 months, with an average of 11.8 months. No tumor was found on the osteotomy surface; the customized prosthesis were firmly installed and closely matched with the retained articular surface. The tumor outcome of neoadjuvant chemotherapy was stable in 4 cases and partial remission in 6 cases. No local recurrence or distant metastasis was found in 9 cases after postoperative adjuvant chemotherapy; pulmonary metastasis was found in 1 case at 12 months after operation. Two patients had local incision fat liquefaction, superficial infection, and delayed healing at 14 days after operation; 1 patient had local bone absorption at the contact surface of the prosthesis, and the screw and prosthesis did not loosen at 7 months after operation; the other patients had good incision healing, with no infection, prosthesis loosening, fracture, or other complications. At 6 months after operation, the MSTS93 score was 19-28, with an average of 24.1; 8 cases were excellent and 2 cases were good. The VAS score was 0.9±1.0, which significantly improved when compared with before operation (5.9±1.0) ( t=23.717, P<0.001). The height of the patients increased by 1-12 cm, with an average of 4.6 cm. At last follow-up, 4 patients had limb length discrepancy, with a length difference of 1 cm in 2 cases and 2 cm in 2 cases. The application of 3D printed customized prosthesis in the resection and reconstruction of adolescents femoral primary malignant tumors can achieve the purpose of preserving epiphysis and articular surface, and obtain good effectiveness.

Three-dimensional-printed titanium prostheses with bone trabeculae enable mechanical-biological reconstruction after resection of bone tumours.

ABSTRACTReconstruction after resection has always been an urgent problem in the treatment of bone tumours. There are many methods that can be used to reconstruct bone defects; however, there are also many complications, and it is difficult to develop a safe and effective reconstruction plan for the treatment of bone tumours. With the rapid development of digital orthopaedics, three-dimensional printing technology can solve this problem. The three-dimensional printing of personalised prostheses has many advantages. It can be used to print complex structures that are difficult to fabricate using traditional processes and overcome the problems of stress shielding and low biological activity of conventional prostheses. In this study, 12 patients with bone tumours were selected as research subjects, and based on individualised reverse-engineering design technology, a three-dimensional model of each prosthesis was designed and installed using medical image data. Ti6Al4V was used as the raw material to prepare the prostheses, which were used to repair bone defects after surgical resection. The operation time was 266.43 ± 21.08 minutes (range 180-390 minutes), and intraoperative blood loss was 857.26 ± 84.28 mL (range 800-2500 mL). One patient had delayed wound healing after surgery, but all patients survived without local tumour recurrence, and no tumour metastasis was found. No aseptic loosening or structural fracture of the prosthesis, and no non-mechanical prosthesis failure caused by infection, tumour recurrence, or progression was observed. The Musculo-Skeletal Tumour Society (MSTS) score of limb function was 22.53 ± 2.09 (range 16-26), and ten of the 12 patients scored ≥ 20 and were able to function normally. The results showed that three-dimensional printed prostheses with an individualised design can achieve satisfactory short-term clinical efficacy in the reconstruction of large bone defects after bone tumour resection.

Usefulness of Trabecular Metal Cones in Revision Total Knee Arthroplasty in a Korean Population: A Case Series.

PurposeThe purpose of this study was to assess the medium-term results of trabecular metal cones for the reconstruction of large bone defects in revision TKA.MethodsThirteen patients who had undergone revision TKA using trabecular metal cones for femoral and/or tibial large bone defects were identified. We included patients who had a minimum of three years follow-up in the study. We evaluated their functional outcomes, implant survivorship, radiological findings, and complications.ResultsAt a mean follow-up of 6.9 years (range of 3.5–9.4 years), all trabecular metal cones and implants were well fixed and did not exhibit any radiographic evidence of migration or loosening. At the final follow-up, the mean Knee Society knee scores had improved from 37.2 to 78.1 (p < 0.05), and function scores had improved from 35.5 to 77.5 points (p < 0.05). One intraoperative fracture in the distal femur occurred in an 85-year-old woman during impaction of a single trabecular metal cone. The fracture was successfully affixed to the femoral cone and bone three months postoperatively.ConclusionThe present study of trabecular metal cones demonstrates excellent clinical outcomes and survivorship in revision TKA during medium-term follow-up periods. However, longer-term follow-up studies are needed to further investigate these implants in revision TKA. Additionally, the necessity of metal cones in revision procedures should be carefully considered depending on patient needs and economic capabilities.

Engineering hypertrophic cartilage grafts from lipoaspirate for critical-sized calvarial bone defect reconstruction: An adipose tissue-based developmental engineering approach.

Developmental engineering of living implants from different cell sources capable of stimulating bone regeneration by recapitulating endochondral ossification (ECO) is a promising strategy for large bone defect reconstruction. However, the clinical translation of these cell‐based approaches is hampered by complex manufacturing procedures, poor cell differentiation potential, and limited predictive in vivo performance. We developed an adipose tissue‐based developmental engineering approach to overcome these hurdles using hypertrophic cartilaginous (HyC) constructs engineered from lipoaspirate to repair large bone defects. The engineered HyC constructs were implanted into 4‐mm calvarial defects in nude rats and compared with decellularized bone matrix (DBM) grafts. The DBM grafts induced neo‐bone formation via the recruitment of host cells, while the HyC pellets supported bone regeneration via ECO, as evidenced by the presence of remaining cartilage analog and human NuMA‐positive cells within the newly formed bone. However, the HyC pellets clearly showed superior regenerative capacity compared with that of the DBM grafts, yielding more new bone formation, higher blood vessel density, and better integration with adjacent native bone. We speculate that this effect arises from vascular endothelial growth factor and bone morphogenetic protein‐2 secretion and mineral deposition in the HyC pellets before implantation, promoting increased vascularization and bone formation upon implantation. The results of this study demonstrate that adipose‐derived HyC constructs can effectively heal large bone defects and present a translatable therapeutic option for bone defect repair.

Case Report: Large bone defect reconstruction in lower extremities with ipsilateral transposition fibular graft with combined inlay and onlay technique using plate and screw fixation (fibula pro tibia technique)

Introduction: Management of large bone defect is a challenging problem. Hahns, in 1884, introduced the first use of fibula pro tibia to bridge a large defect of the tibia due to chronic osteomyelitis. In this case, we did a transposition of the ipsilateral fibular with inlay and onlay technique using a locking plate and screw into the defect of the tibia. Case presentation: A 20-year-old male came to our emergency department at RSUD Dr. Saiful Anwar, Malang, Indonesia with an open fracture grade III B of his left lower leg. We found a large defect of the tibia approximately 7.5 cm after regular wound care for ten months. Then, we performed ipsilateral transposition fibular graft with combined inlay and onlay technique using a locking plate and screw fixation. No infections occurred and there was progressive callus formation with extending ossification along the periosteal tissue in the four-month postoperative evaluation. There was no leg length discrepancy, and the union sign showed that the patient could achieve full range of movement (ROM) and walk with crutches without pain with a Lower Extremity Functional Scale (LEFS) score of 62. Discussion: Contralateral fibula graft carries a high risk of endangering the unaffected limb. The ipsilateral fibula can be utilized to replace the missing segment with minimal morbidity. The purpose of combining ipsilateral fibular transport with the inlay and onlay technique is to minimalize the gap defect between fracture fragments, therefore enhancing the union rate of the bone. Conclusion: The fibula pro tibia technique can be used as an alternative treatment option for large gap bone defects in lower extremities with minimal complication.

Algorithm of surgical treatment of large bone defects of long tubular bones by vascularized bone grafting

The purpose of this study was to develop a clinical classification of large defects of long tubular bones of the extremities and protocols for surgical treatment by vascularized bone grafting.Material and methods. The results of treatment of 51 patients with large defects of the long tubular bones of the upper and lower extremities were analyzed. In 25 cases, along with bone defects, there were significant defects of the soft tissues of the limb with trophic and scar changes. In order to replace the bone defect vascularized grafts were used: bone-muscular fibular, bone-cutaneous fibular, bone-cutaneous iliac, bone-cutaneous radial, bone-cutaneous tibial, and combined bone-cutaneous fibular with an allograft from the tibia. The results of treatment of patients were evaluated according to the clinical criteria of R. Johner, O. Wruhs (1983), proposed for the lower limb. The DASH questionnaire was use to evaluate the results of treatment for upper limb defects.The results and discussion. The classification is based on 4 variable criteria: the size, anatomical localization of the bone defect, the size of the soft tissue defect and the shortening of the damaged limb segment. The size and anatomical location of the defect in the long tubular bone is important in choosing a bone flap. Based on the anatomical localization of the bone defect, soft tissue damage and limb shortening, the patients were classified into 4 types. The first 3 types were divided into 2 subtypes, depending on the size of bone damage and soft tissues defect of the limb. Based on the proposed classification, we have developed protocols for microsurgical reconstruction of large bone defects of the extremities for each subtype of bone defect.Conclusion. The application of the developed clinical classification of large bone defects of long tubular bones and protocols for their surgical treatment by vascularized bone grafting made it possible to restore limb function in 96% of cases.

Evaluation of Human Bone Marrow Mesenchymal Stromal Cell (MSC) Functions on a Biomorphic Rattan-Wood-Derived Scaffold: A Comparison between Cultured and Uncultured MSCs.

The reconstruction of large bone defects requires the use of biocompatible osteoconductive scaffolds. These scaffolds are often loaded with the patient’s own bone marrow (BM) cells to facilitate osteoinductivity and biological potency. Scaffolds that are naturally sourced and fabricated through biomorphic transitions of rattan wood (B-HA scaffolds) offer a unique advantage of higher mechanical strength and bioactivity. In this study, we investigated the ability of a biomorphic B-HA scaffold (B-HA) to support the attachment, survival and gene expression profile of human uncultured BM-derived mesenchymal stromal cells (BMSCs, n = 6) and culture expanded MSCs (cMSCs, n = 7) in comparison to a sintered, porous HA scaffold (S-HA). B-HA scaffolds supported BMSC attachment (average 98%) and their survival up to 4 weeks in culture. Flow cytometry confirmed the phenotype of cMSCs on the scaffolds. Gene expression indicated clear segregation between cMSCs and BMSCs with MSC osteogenesis- and adipogenesis-related genes including RUNX2, PPARγ, ALP and FABP4 being higher expressed in BMSCs. These data indicated a unique transcriptional signature of BMSCs that was distinct from that of cMSCs regardless of the type of scaffold or time in culture. There was no statistical difference in the expression of osteogenic genes in BMSCs or cMSCs in B-HA compared to S-HA. VEGF release from cMSCs co-cultured with human endothelial cells (n = 4) on B-HA scaffolds suggested significantly higher supernatant concentration with endothelial cells on day 14. This indicated a potential mechanism for providing vasculature to the repair area when such scaffolds are used for treating large bone defects.

Three-Dimensional Osteogenic Differentiation of Bone Marrow Mesenchymal Stem Cells Promotes Matrix Metallopeptidase 13 (MMP13) Expression in Type I Collagen Hydrogels.

Autologous bone transplantation is the principal method for reconstruction of large bone defects. This technique has limitations, such as donor site availability, amount of bone needed and morbidity. An alternative to this technique is tissue engineering with bone marrow-derived mesenchymal stem cells (BMSCs). In this study, our aim was to elucidate the benefits of culturing BMSCs in 3D compared with the traditional 2D culture. In an initial screening, we combined BMSCs with four different biogels: unmodified type I collagen (Col I), type I collagen methacrylate (ColMa), an alginate and cellulose-based bioink (CELLINK) and a gelatin-based bioink containing xanthan gum (GelXA-bone). Col I was the best for structural integrity and maintenance of cell morphology. Osteogenic, adipogenic, and chondrogenic differentiations of the BMSCs in 2D versus 3D type I collagen gels were investigated. While the traditional pellet culture for chondrogenesis was superior to our tested 3D culture, Col I hydrogels (i.e., 3D) favored adipogenic and osteogenic differentiation. Further focus of this study on osteogenesis were conducted by comparing 2D and 3D differentiated BMSCs with Osteoimage® (stains hydroxyapatite), von Kossa (stains anionic portion of phosphates, carbonates, and other salts) and Alizarin Red (stains Ca2+ deposits). Multivariate gene analysis with various covariates showed low variability among donors, successful osteogenic differentiation, and the identification of one gene (matrix metallopeptidase 13, MMP13) significantly differentially expressed in 2D vs. 3D cultures. MMP13 protein expression was confirmed with immunohistochemistry. In conclusion, this study shows evidence for the suitability of type I collagen gels for 3D osteogenic differentiation of BMSCs, which might improve the production of tissue-engineered constructs for treatment of bone defects.