Morbidity at bone graft donor sites

The Role of Bone Grafting in Corrective Osteotomy of Distal Radius Malunions

Background  It remains unclear whether bone grafting is required during corrective osteotomy of the distal radius. The goal of this systematic review is to determine the union, revision, and complication rates of bone grafting techniques associated with extra-articular corrective osteotomy for dorsally malunited distal radius fractures treated with volar plating. Questions  Is bone grafting in distal radius corrective osteotomy associated with increased rates of bone union and reduced rates of revision surgery and complications? Materials and Methods  A comprehensive search of the MEDLINE, Embase, and Cumulative Index to Nursing and Allied Health Literature databases was completed for studies reporting clinical outcomes of extra-articular corrective osteotomy for dorsally malunited distal radius fractures treated with volar plating. Results  A total of 13 studies, with 14 intervention arms and 236 patients, were included. Bone grafting techniques consisted of autograft (6 studies, n  = 93), synthetic bone grafts (2 studies, n  = 38), allograft (1 study, n  = 14), or no grafting (5 studies, n  = 91). The overall union rate was 97%, and the mean time-to-union was 12.0 weeks. Larger corrections of dorsal tilt and ulnar variance were performed in the autograft and allograft groups. Complication and revision rates were highest in the synthetic group, 45 and 26.3% respectively. Conclusion  Grafting in extra-articular corrective osteotomy for dorsally angulated distal radius malunions treated with volar plating is not associated with an improved union rate in the literature. However, larger corrections were achieved in both the autograft and allograft groups compared to the no-graft and synthetic groups, resulting in similar union rates. Synthetic bone grafting was associated with the highest complication and revision rates. Future comparative prospective trials and proper documentation of whether cortical contact was present or absent are required to assess whether bone grafting warrants consideration in more advanced deformities. Level of Evidence  IV.

DNA as a promising biomaterial for bone regeneration and potential mechanisms of action

DNA nanotechnology has created new possibilities for the use of DNA in tissue regeneration - an important advance for DNA use beyond its paradigmatic role as the hereditary biomacromolecule. Biomaterials containing synthetic or natural DNA have been proposed for several applications including drug and gene delivery, and more recently, as osteoconductive biomaterials. This review provides an in-depth discussion of studies that have used DNA-based materials for biomineralization and/or bone repair, with expansion on the topic of DNA hydrogels specifically, and the advantages they offer for advancing the field of bone regeneration. Four mechanisms of action for the osteoconductive capabilities of DNA-based materials are discussed, and a proposed model for degradation of these materials and its link to their osteoconductive properties is later presented. Finally, the review considers current limitations of DNA-based materials and summarizes important aspects that need to be addressed for future application of DNA nanotechnology in tissue repair. STATEMENT OF SIGNIFICANCE: Herein we summarize the developing field of DNA-based materials for biomineralization and bone repair, with a focus on DNA hydrogels. We first provide a comprehensive review of different forms of DNA-based materials described thus far which have been shown to enhance bone repair and mineralization (namely DNA coatings, DNA-containing pastes, DNA nanostructures and DNA hydrogels). Next, we describe four different mechanisms by which DNA-based materials could be exerting their osteogenic effect. Then, we propose a novel model that links DNA degradation and osteoconductivity. Lastly, we suggest possible research directions to enhance DNA-based materials for future clinical application. The suggested mechanisms and the proposed model can guide future research to better understand how DNA functions as a mineral- and bone-promoting molecule.

The Role of Crosslinking Agents in the Development of Collagen-Hydroxyapatite Composite Materials for Bone Tissue Engineering

The lack of bone grafts represents a major issue in the orthopedic field, reconstructive surgery, and dentistry. There are several bone conditions that often demand the use of grafts, such as fractures, infections, and bone cancer. The number of bone cancer cases increased in the past few decades and along with it, the need for bone grafting materials. To avoid the use of autografts and allografts there has been an increased interest towards synthetic grafts. This research aims to develop some collagen/hydroxyapatite (Coll/HAp) scaffolds cross-linked with three different agents that could be used in bone tissue engineering (BTE). These scaffolds were obtained with a freeze-drying method after the in situ formation of hydroxyapatite inside the collagen matrix. They were structurally and morphologically characterized and evaluated in terms of antimicrobial activity on E. coli and S. aureus bacterial strains. The results revealed that the scaffolds have porous structures with interconnected pores of suitable dimensions and well-distributed inorganic phases. Coll/HAp samples showed great antibacterial activity even without the use of typically used antibacterial agents. These findings allow us to conclude that these scaffolds are promising candidates for use in BTE and bone cancer treatment after the incorporation of specific antitumoral drugs.

Early Single-Stage Curettage and Autogenous Bone Grafting for Enchondroma in the Hand with Minimally Displaced Pathologic Fracture

Backgroud

Enchondroma is a common benign bone tumor in the hand, often leading to delayed diagnosis due to its asymptomatic nature. The surgical treatment strategy for enchondroma, particularly in pathologic fractures, remains unclear. This study aimed to evaluate the outcomes of treatment for non- or minimally displaced pathologic fractures in enchondroma using autogenous bone grafts alone, without metal fixation.

Methods

A retrospective analysis was conducted on 34 patients who underwent surgery for enchondroma and pathologic fractures. Clinical and radiographic outcomes were assessed, including pain scores, range of motion (ROM), Disabilities of the Arm, Shoulder, and Hand (DASH) score, grip strength, fracture union time, and complications.

Results

All patients reported pain at the fracture site preoperatively. The preoperative pain visual analog scale (VAS) score was 4.5. Postoperatively, the pain VAS score improved significantly to 2.3. The postoperative average total ROM was 253.8°. The average DASH score was 5.1, and grip strength was 97.8% compared to the unaffected side. Bony union was achieved in all cases with an average union time of 10.9 weeks. No complications were observed except for 1 suspected recurrence.

Conclusions

Early single-stage surgical treatment with curettage and autogenous bone grafts without fixation yielded satisfactory results for non- or minimally displaced pathologic fractures in enchondroma. This non-fixative technique offers a viable option with reduced treatment duration and implant-related complications.

Safety and performance of a novel synthetic biomimetic scaffold for iliac crest defect reconstruction during surgical treatment of pelvic girdle pain: a first-in-human trial

INTRODUCTION

Surgical treatment of pelvic girdle pain (PGP) involves arthrodesis of sacroiliac (SI) and pubic symphysis joints. Fusion of pubic symphysis involves the implantation of an autologous iliac crest tricortical graft harvested from the iliac crest. The objective was to assess the safety of a novel synthetic graft substitute (b.Bone) for iliac crest reconstruction and to evaluate the results of PGP surgical treatment.

SOURCES OF DATA

Consecutive participants undergoing pelvic fusion and requiring iliac crest reconstruction were enrolled and followed-up for 12 months in a prospective first-in-human clinical investigation. Adverse events were documented, and health-related quality of life was evaluated using EuroQol-5D-5L questionnaire. Iliac crest defect healing was evaluated by the Modified Lane and Sandhu radiological scoring system. In addition, relevant published peer-reviewed scientific articles identified from PubMed.

AREAS OF AGREEMENT

The EQ-5D-5L scores improved steadily reaching the highest point at 365 days. By 365 days complete healing of the bone defect was observed.

AREAS OF CONTROVERSY

The management of PGP remains challenging with mixed results reported in the literature.

GROWING POINTS

While there is lack of consensus on how to manage PGP, the present study shows improved outcomes at one year following surgery. The synthetic b.Bone scaffold is a safe option with good healing outcomes for iliac crest defect reconstruction.

AREAS TIMELY FOR DEVELOPING RESEARCH

Although b.Bone synthetic scaffold found to be safe, further studies reporting on surgical treatment of PGP are required to confirm the findings in comparative trials.

From Waste to Innovation: A Circular Economy Approach for Tissue Engineering by Transforming Human Bone Waste into Novel Collagen Membranes

The aim of the circular economy is to treat waste as a valuable raw material, reintegrating it into the industrial economy and extending the lifecycle of subsequent products. Efforts to reduce the production of hard-to-recycle waste are becoming increasingly important to manufacturers, not only of consumer goods but also of specialized items that are difficult to manufacture, such as medical supplies, which have now become a priority for the European Union. The purpose of the study is to manufacture a novel human-purified type I collagen membrane from bone remnants typically discarded during the processing of cortico-cancellous bones in tissue banks and to evaluate its mechanical properties and effectiveness in regenerating bone-critical mandibular defects in rabbits. To prepare the novel membrane, cortico-cancellous bone chip samples from a local tissue bank were processed to isolate collagen by demineralization under agitation in HCl, cast into a silicone mold, and air-dried at room temperature and UV irradiation. The average thickness of the four batches analyzed by SEM was 37.3 μm. The average value of Young's modulus and tensile strength obtained from the specimens was 2.56 GPa and 65.43 Mpa, respectively. The membrane's efficacy was tested by creating a critical bicortical and bilateral osteoperiosteal defect in rabbit mandibles. The right-side defects were covered with the collagen membrane, while the left-side defects were left untreated as a control. Nine weeks post-surgery, clinical, radiological, and histological analyses demonstrated new bone formation in the treated areas, whereas the control sites showed no bone regeneration. This innovative approach not only contributes to sustainability in healthcare by optimizing biological waste but also exemplifies efficient resource use in line with the circular economy, offering a cost-effective, biocompatible option that could benefit national health systems.

Mimicking the Bone Extracellular Matrix through a Calcium Phosphate-Containing Thiol-Ene Cross-Linked Gelatin Composite

Hydroxyapatite (HAP) and amorphous calcium phosphate (ACP) nanoparticles were incorporated into a thiol-ene clickable gelatin network to elucidate to what extent osteogenic differentiation of human dental pulp- and adipose-derived stem cells (HDPSCs/HASCs) could be further boosted. ACP nanoparticles increased the specific surface area by 23% and reduced the density by 13% while maintaining a comparable particle size (ACP: 25 ± 3 nm; HAP: 27 ± 3 nm). Overall, the incorporation of ceramic nanoparticles did not significantly alter the mechanical properties of the ceramic-containing composites compared to the unsubstituted thiol-ene network. ACP nanoparticles at high concentrations promoted a 21-day osteogenic response in HASCs (72.09 ± 20.20 ng Ca2+/ng DNA) comparable to HDPSCs, with the latter showing high calcium production irrespective of the ceramic content (78.45 ± 10.87 ng Ca2+/ng DNA), suggesting that the provided cues must be optimized according to the investigated cell type toward a cell-interactive coating application stimulating osteogenesis.

A safe, novel and ingenious method for autogenous bone graft storage in spine surgery with constrained resources - operative site as the bone bank

BACKGROUND

The aim of our study is to establish whether the bone graft harvested and stored in the surgical wound by our novel technique is safe, reproducible and preserves the viability of the graft. In doing so, it promises successful bony fusion in spine and orthopaedic surgeries.

METHODS

A prospective clinical case series was conducted for autogenous bone graft storage in complex spine surgeries requiring staged procedures, in resource constrained settings. The bone graft harvested was morselized, wrapped in moist sterile gauze and stored in the paraspinal gutter within the operative site. Thereafter, the surgical wound was easily closed without tension. During the second stage surgery, the stored bone was retrieved and mixed with more autologous/allogenic bone (if necessary) and appropriately laid at fusion sites. Bacterial samples were sent before implantation.

RESULTS

16 complex spinal deformity patients who underwent surgery in a resource constrained hospital over a period of 5 years were included. Duration between both stages was within 2 weeks. All patients showed successful fusion, with mean follow-up of 2.6 years. There were no cases of deep or systemic infection in our series. Surgeons found harvesting, storing and retrieval of graft to be straightforward.

CONCLUSION

The operative site provides an ideal, safe and reproducible location for bone graft storage for staged surgeries conducted in resource constrained situations. The osteogenic potential of the autogenous bone graft is retained. This technique can be extrapolated to other orthopaedic surgeries conducted under resource limited environments like in surgical camps or combat medical facilities.

Platelets: A Potential Factor that Offers Strategies for Promoting Bone Regeneration

Bone defects represent a prevalent category of clinical injuries, causing significant pain and escalating health care burdens. Effectively addressing bone defects is thus of paramount importance. Platelets, formed from megakaryocyte lysis, have emerged as pivotal players in bone tissue repair, inflammatory responses, and angiogenesis. Their intracellular storage of various growth factors, cytokines, and membrane protein receptors contributes to these crucial functions. This article provides a comprehensive overview of platelets' roles in hematoma structure, inflammatory responses, and angiogenesis throughout the process of fracture healing. Beyond their application in conjunction with artificial bone substitute materials for treating bone defects, we propose the potential future use of anticoagulants such as heparin in combination with these materials to regulate platelet number and function, thereby promoting bone healing. Ultimately, we contemplate whether manipulating platelet function to modulate bone healing could offer innovative ideas and directions for the clinical treatment of bone defects. Impact statement Given that 5-10% of fracture patients with delayed bone healing or even bone nonunion, this review explores the potential role of platelets in bone healing (directly/indirectly) and proposes ideas and directions for the future as to whether it is possible to promote bone healing and improve fracture healing rates by modulating platelets.

Platelet rich fibrin as a bioactive matrix with proosteogenic and proangiogenic properties on human healthy primary cells in vitro

Blood concentrates like platelet rich fibrin (PRF) have been established as a potential autologous source of cells and growth factors with regenerative properties in the field of dentistry and regenerative medicine. To further analyze the effect of PRF on bone tissue regeneration, this study investigated the influence of liquid PRF matrices on human healthy primary osteoblasts (pOB) and co-cultures composed of pOB and human dermal vascular endothelial cells (HDMEC) as in vitro model for bone tissue regeneration. Special attention was paid to the PRF mediated influence on osteoblastic differentiation and angiogenesis. Based on the low-speed centrifugation concept, cells were treated indirectly with PRF prepared with a low (44 g) and high relative centrifugal force (710 g) before the PRF mediated effect on osteoblast proliferation and differentiation was assessed via gene and protein expression analyses and immunofluorescence. The results revealed a PRF-mediated positive effect on osteogenic proliferation and differentiation accompanied by increased concentration of osteogenic growth factors and upregulated expression of osteogenic differentiation factors. Furthermore, it could be shown that PRF treatment resulted in an increased formation of angiogenic structures in a bone tissue mimic co-culture of endothelial cells and osteoblasts induced by the PRF mediated increased release of proangiogenic growth factors. The effects on osteogenic proliferation, differentiation and vascularization were more evident when low RCF PRF was applied to the cells. In conclusion, PRF possess proosteogenic, potentially osteoconductive as well as proangiogenic properties, making it a beneficial tool for bone tissue regeneration.

Differences in Outcomes Based on the Degree to Which Bone Defects Are Filled with Cancellous Allochip Bone Grafts in Hand Enchondroma Patients

BACKGROUND/OBJECTIVES

Enchondroma, the most common benign cartilage tumor in the hand, often presents as pain, swelling, or pathological fractures. While curettage is the standard treatment preventing fractures, the optimal way of managing the bone cavity remains debated. In this study, we investigated the impact of a filled bone defect on radiologic and clinical outcomes among patients with enchondroma.

METHODS

We retrospectively reviewed patients with solitary enchondroma of the hand who underwent curettage followed by allogeneic cancellous bone chip impaction grafting. The patients were divided into two groups based on the extent to which their bone defects were filled post-curettage: Group 1 (complete filling) and Group 2 (incomplete filling, i.e., <50%). We reviewed demographic data, local recurrence data, complications, information on consolidation duration, data on range of motion (ROM), and functional scores.

RESULTS

This study included 59 patients (25 males and 34 females; mean age, 30.4 ± 11.9 years, with a range of 8-78). Group 1 contained 35 patients, and Group 2 contained 24. No nonunion occurred following curettage and grafting. The mean radiological consolidation period was 6.4 weeks (range: 5-18). There was no significant difference in consolidation time between Group 1 (6.8 weeks) and Group 2 (6.9 weeks) (p = 0.166). The ROM and functional scores also showed no significant differences between the groups, with musculoskeletal society scores of 98.8 for Group 1 and 99.8 for Group 2 (p = 0.63).

CONCLUSIONS

This study demonstrates that the use of the impaction technique combined with cancellous allochip bone grafting yields favorable results in the treatment of solitary hand enchondroma. The extent to which the bone defect was filled did not significantly impact the overall outcomes.

Advances in Bioceramics for Bone Regeneration: A Narrative Review

Large osseous defects resulting from trauma, tumor resection, or fracture render the inherent ability of the body to repair inadequate and necessitate the use of bone grafts to facilitate the recovery of both form and function of the bony defect sites. In the United States alone, a large number of bone graft procedures are performed yearly, making it an essential area of investigation and research. Synthetic grafts represent a potential alterative to autografts due to their patient-specific customizability, but currently lack widespread acceptance in the clinical space. Early in their development, non-autologous bone grafts composed of metals such as stainless steel and titanium alloys were favorable due to their biocompatibility, resistance to corrosion, mechanical strength, and durability. However, since their inception, bioceramics have also evolved as viable alternatives. This review aims to present an overview of the fundamental prerequisites for tissue engineering devices using bioceramics as well as to provide a comprehensive account of their historical usage and significant advancements over time. This review includes a summary of commonly used manufacturing techniques and an evaluation of their use as drug carriers and bioactive coatings-for therapeutic ion/drug release, and potential avenues to further enhance hard tissue regeneration.

Comparing Open and Arthroscopic Grafting for Scaphoid Nonunion: Is There Truly a Noticeable Difference?

BACKGROUND

Scaphoid nonunion remains a challenging injury with no clear consensus on treatment. Surgical options, such as bone grafting procedures, are available for the treatment of scaphoid nonunions. While open grafting provides direct visualization, it is theoretically believed to lead to several problems due to the complex ligamentous structure responsible for wrist stability and challenges in the vascular supply of the scaphoid. On the other hand, despite its technical challenges, arthroscopic grafting is thought to avoid complications by preserving surrounding tissues.

QUESTIONS/PURPOSES

(1) Do patients undergoing bone grafting via arthroscopy for scaphoid nonunion report better function than patients undergoing an open procedure? (2) Do patients undergoing bone grafting via arthroscopy for scaphoid nonunion demonstrate better objective outcomes, such as ROM, extremity strength, and bony union?

METHODS

Between January 2012 and January 2022, we operated on 141 patients with scaphoid nonunion. The following patients were excluded from this study: 33 patients with scaphoid nonunion advanced collapse and arthritis, 18 patients with proximal pole fractures, 5 patients with previous surgeries, 16 patients with avascular necrosis, and 8 patients with the radius used as a graft source. In total, 28 patients underwent open grafting, and 33 patients underwent arthroscopic grafting; for both groups, the iliac crest was used as the graft source. Two patients with nonunion were observed in each treatment group, and they were excluded from the study. Results from the remaining 26 patients treated with open grafting and 31 patients treated with arthroscopic grafting (totaling 57 patients) were analyzed. The decision to treat patients with open or arthroscopic methods was not based on a particular reason. In our clinic, we initially preferred open grafting for treating nonunion of the scaphoid. Subsequently, we began to prefer arthroscopic methods for the treatment of these injuries. Twenty patients in the arthroscopic group had additional ligamentous injuries, which were simultaneously treated arthroscopically. All patients in both groups had at least 1 year of follow-up, but 48% of patients treated arthroscopically and 42% of those treated with open approaches were lost before 2 years of follow-up. The remaining patients had follow-up periods longer than 24 months. Our primary analysis was performed at 1 year, and we did a secondary analysis at 2 years. We compared the Patient-Rated Wrist Evaluation (PRWE), QuickDASH, and VAS scores of the patients. We also compared ROM and grip and pinch strength in patients' contralateral wrists. We used predefined, evidence-based thresholds for the minimum clinically important differences for these outcome measures.

RESULTS

According to the 1-year functional analysis, we found no clinically important difference between the open surgery group and the arthroscopic surgery group in terms of PRWE score (median [IQR] 19 [25] versus 8 [9], difference of medians 11; p = 0.001), QuickDASH (median 14 [23] versus 7 [11], difference of medians 7; p = 0.004), and VAS scores (median 2 [2] versus 1 [1], difference of medians 1; p = 0.02). At 1 year, there were no differences in objective measurements, including grip strength (median 81 [16] versus 85 [14], difference of medians 4; p = 0.60), pinch strength (median 82 [18] versus 81 [15], difference of medians 1; p = 0.85), and ROM (flexion-extension median 83 [22] versus 85 [13], difference of medians 2; p = 0.74; radial deviation-ulnar deviation median 80 [36] versus 85 [14], difference of medians 5; p = 0.61). In the 2-year analysis, no clinically important difference was observed in terms of PRWE score, and no differences were found in terms of QuickDASH, VAS, strength tests, and ROM between the open and arthroscopic groups. No difference was observed in the union rates between the open group and the arthroscopic group (93% [26 of 28] versus 94% [31 of 33], OR 1.19 [95% CI 0.16 to 9.06]; p = 0.86).

CONCLUSION

In comparing open surgical procedures with arthroscopic techniques for the treatment of scaphoid nonunions, the present study revealed no differences in functional outcomes and objective measures such as ROM and strength tests at both the 1-year and 2-year follow-up visits. Although technically more challenging, arthroscopy provides a potential advantage, such as addressing concomitant ligament injuries simultaneously. However, patients did not perceive a difference between the two surgical methods. In future studies, investigating long-term outcomes in a larger population will contribute to better elucidating this issue.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Synthetic Bone Blocks Produced by Additive Manufacturing in the Repair of Critical Bone Defects

This study evaluated the efficacy of synthetic bone blocks, composed of hydroxyapatite (HA) or β-tricalcium phosphate (B-TCP), which were produced by additive manufacturing and used for the repair of critical size bone defects (CSDs) in rat calvaria. Sixty rats were divided into five groups (n = 12): blood clot (CONTROL), 3D-printed HA (HA), 3D-printed β-TCP (B-TCP), 3D-printed HA + autologous micrograft (HA+RIG), and 3D-printed β-TCP + autologous micrograft (B-TCP+RIG). CSDs were surgically created in the parietal bone and treated with the respective biomaterials. The animals were euthanized at 30 and 60 days postsurgery for microcomputed tomography (micro-CT) histomorphometric, and immunohistochemical analysis to assess new bone formation. Micro-CT analysis showed that both biomaterials were incorporated into the animals' calvaria. The HA+RIG group, especially at 60 days, exhibited a significant increase in bone formation compared with the control. The use of 3D-printed bioceramics resulted in thinner trabeculae but a higher number of trabeculae compared with the control. Histomorphometric analysis showed bone islands in close contact with the B-TCP and HA blocks at 30 days. The HA blocks (HA and HA+RIG groups) showed statistically higher new bone formation values with further improvement when autologous micrografts were included. Immunohistochemical analysis showed the expression of bone repair proteins. At 30 days, the HA+RIG group had moderate Osteopontin (OPN) staining, indicating that the repair process had started, whereas other groups showed no staining. At 60 days, the HA+RIG group showed slight staining, similar to that of the control. Osteocalcin (OCN) staining, indicating osteoblastic activity, showed moderate expression in the HA and HA+RIG groups at 30 days, with slight expression in the B-TCP and B-TCP+RIG groups. The combination of HA blocks with autologous micrografts significantly enhanced bone repair, suggesting that the presence of progenitor cells and growth factors in the micrografts contributed to the improved outcomes. It was concluded that 3D-printed bone substitute blocks, associated with autologous micrografts, are highly effective in promoting bone repair in CSDs in rat calvaria.

Proximal tibia for alveolar augmentation and augmentative rhinoplasty-a suitable option? A retrospective clinical study on donor and recipient site morbidity

BACKGROUND

Autologous bone grafts are essential in reconstructive oral and maxillofacial surgery, and depending on the donor site, they can be associated with specific harvesting morbidities. One of the most commonly applied bone grafts is the iliac crest bone graft, irrespective of other grafts, which might be associated with an easier surgical procedure or the possibility of harvesting them under local anaesthesia. Objective of the study is the clinical evaluation of proximal tibia bone grafts regarding their eligibility for maxillofacial bone grafting.

METHODS

In this retrospective study, proximal tibia bone grafts were examined with regard to associated donor and recipient site morbidity and their suitability for alveolar ridge augmentation and rhinoplasty.

RESULTS

In total, 21 tibia grafts were included. Fifty-seven percent of the bone grafts were used for alveolar ridge reconstruction, and 43% were used for augmentative rhinoplasty. No significant complications occurred during or after harvesting, but in 14.3% of the patients, minor wound healing disorders were recorded at the donor site, and in 19% of the patients, they were recorded at the recipient site. Statistically, patient sex, age, nicotine and alcohol abuse and metabolic diseases had no significant influence on the complication rate. Graft harvesting under local anaesthesia and at summer temperatures was associated with significantly more complications at the harvesting site (p < 0.05). In cases of dental implant insertion into augmented sites, the implants (n = 31) were followed up for a median period of 40.5 months, during this time 86.7% of the implants survived.

CONCLUSION

The proximal tibia is a suitable donor site for harvesting autologous bone grafts for alveolar ridge augmentation or rhinoplasty because the donor site morbidity is low, and in contrast to iliac crest bone grafts, they can be harvested under local anaesthesia, which might be advantageous for outpatient surgeries.

Early bone graft donor site morbidities; anterior superior iliac crest versus proximal tibia

PURPOSE

Autogenous bone grafting is a widely used technique in orthopaedic and reconstructive surgeries. The anterior superior iliac crest (AIC) and proximal tibia (PT) are common sources for bone grafts. While, AIC is the gold standard, PT is popular for lower extremity procedures due to its proximity. The research investigates early complications associated with these donor sites in a tertiary orthopaedic centre in Nigeria.

METHODS

This randomized controlled study was conducted from July 2020 to December 2021. It includes 66 patients randomized into AIC and PT groups. Pain score analysis and the incidence of surgical site infections were compared between both groups.

RESULTS

There was no statistical difference in the incidence of surgical site infections (SSI) in both groups. The study also reveals that patients in the AIC group experienced more significant pain in the immediate postoperative period and up to two weeks after surgery, with the severity particularly pronounced on the first postoperative day. (p < 0.001).

C CONCLUSIONS

The PT had less pain severity than the AIC bone graft donor sites. The authors recommend that surgeons consider PT if bone grafting is required.

Current State and Challenges of Tissue and Organ Cryopreservation in Biobanking

Recent years have witnessed significant advancements in the cryopreservation of various tissues and cells, yet several challenges persist. This review evaluates the current state of cryopreservation, focusing on contemporary methods, notable achievements, and ongoing difficulties. Techniques such as slow freezing and vitrification have enabled the successful preservation of diverse biological materials, including embryos and ovarian tissue, marking substantial progress in reproductive medicine and regenerative therapies. These achievements highlight improved post-thaw survival and functionality of cryopreserved samples. However, there are remaining challenges such as ice crystal formation, which can lead to cell damage, and the cryopreservation of larger, more complex tissues and organs. This review also explores the role of cryoprotectants and the importance of optimizing both cooling and warming rates to enhance preservation outcomes. Future research priorities include developing new cryoprotective agents, elucidating the mechanisms of cryoinjury, and refining protocols for preserving complex tissues and organs. This comprehensive overview underscores the transformative potential of cryopreservation in biomedicine, while emphasizing the necessity for ongoing innovation to address existing challenges.

The recent progress of bone regeneration materials containing EGCG

Epigallocatechin-3-gallate (EGCG) is the most effective active ingredient in tea polyphenols and belongs to the category of catechins. EGCG has excellent antioxidant activity, anti-inflammatory, osteogenesis-promoting, and antibacterial properties, and has been widely studied in orthopedic diseases such as osteoporosis. To reach the lesion site, achieve sustained release, promote osteogenesis, regulate macrophage polarization, and improve the physical properties of materials, EGCG needs to be cross-linked or incorporated in bone regeneration materials. This article reviews the application of bone regeneration materials combined with EGCG, including natural polymer bone regeneration materials, synthetic polymer bone regeneration materials, bioceramic bone regeneration materials, metal bone regeneration materials, hydrogel bone regeneration materials and metal-EGCG networks. In addition, the fabrication methods for the regenerated scaffolds are also elaborated in the text. To sum up, it reveals the excellent development potential of materials containing EGCG and the shortcomings of current research, which will provide important reference for the future exploration of bone regeneration materials containing EGCG.

rhBMP-2-loaded hydroxyapatite/beta-tricalcium phosphate microsphere/hydrogel composite promotes bone regeneration in a novel rat femoral nonunion model

Background

Nonunion following fracture treatment remains a significant clinical challenge, adversely affecting the patient's quality of life and imposing a substantial economic burden. The emergence of bone morphogenetic protein 2 (BMP-2) for bone regeneration represents a promising avenue, albeit limited by side effects such as inflammatory reactions primarily due to suboptimal drug delivery systems. This study focuses on NOVOSIS putty (NP), a novel biomaterial designed for the sustained release of BMP-2, aiming to mitigate these limitations and enhance bone healing.

Objective

This research aimed to evaluate the effectiveness of NP, a hydroxyapatite granules/β-tricalcium phosphate hydrogel composite (HA/β-TCP/hydrogel), as a BMP-2 carrier for promoting bone regeneration in a new rat nonunion model of long bone.

Methods

Using Sprague Dawley rats, a 2-mm silicone disk was interposed at the femoral fracture site, and intramedullary fixation with K-wire was performed to create a nonunion with a 2-mm bone defect. After 3 weeks, internal fixation with a plate, removal of the silicon disk, and refreshing the nonunion site were performed by implanting three different materials into the nonunion sites: allogenic iliac bone (IB), collagen sponge (CS) containing 10 μg of BMP-2, or NP containing 10 μg of BMP-2. Bone healing was evaluated weekly using micro-computed tomography (CT); ex vivo micro-Ct and histological evaluation were conducted at 6 weeks.

Results

At 6 weeks, NP demonstrated a significantly higher bone union rate (76.5%) compared with the CS group (35.3%, p = 0.037), and the IB group (6.3%, p < 0.0001). Bone mineral density (BMD) and bone volume/tissue volume (BV/TV) were also significantly higher in the NP group compared with the CS group (BMD, p < 0.0001; BV/TV, p = 0.031). Histological analysis showed the fracture gap in the NP group was filled with more trabecular bone and less fibrous tissue compared with the CS group.

Conclusion

The study confirms NP is a highly effective BMP-2 carrier, significantly improving bone union rates and new bone formation in nonunion fractures. The sustained release of BMP-2 from the hydrogel component reduced inflammatory responses and enhanced bone regeneration. NP can be a promising alternative to collagen-based BMP-2 delivery systems.

Design considerations when creating a high throughput screen-compatible in vitro model of osteogenesis

Inducing osteogenic differentiation in vitro is useful for the identification and development of bone regeneration therapies as well as modelling bone disorders. To couple in vitro models with high throughput screening techniques retains the assay's relevance in research while increasing its therapeutic impact. Miniaturizing, automating and/or digitalizing in vitro assays will reduce the required quantity of cells, biologic stimulants, culture/output assay reagents, time and cost. This review highlights the design and workflow considerations for creating a high throughput screen-compatible model of osteogenesis, comparing and contrasting osteogenic cell type, assay fabrication and culture methodology, osteogenic induction approach and repurposing existing output techniques.

Efficacy and safety of recombinant human bone morphogenetic protein-2 (rhBMP-2) combined with autologous bone for the treatment of long bone nonunion: A report of a prospective case series

INTRODUCTION

Recombinant human Bone morphogenetic proteins have been used for the treatment of nonunions with promising results. We have been investigating both experimentally and clinically the efficacy of the rhBMP-2 with the macro / micro-porous hydroxyapatite carrier granules on the potency on the reconstruction of long bone defect. The purpose of this study was to prospectively evaluate the efficacy and safety of this specific rhBMP-2 with HA carrier granules mixed with autologous cancellous bone in patients with nonunion and bone defect resulted from the fracture related infection.

MATERIALS AND METHODS

This was a retrospective review of a prospective cohort at a university hospital. Patients diagnosed with nonunion under the definition of the United States Food and Drug Administration with bone defect after long bone fractures were enrolled from January 2020 to February 2021. We included patients with atrophic and oligotrophic nonunion, and hypertrophic nonunion with malalignment that needed to be corrected. The other patient group was consisted of segmental bone defect resulted from FRI. The maximum amount of rhBMP-2 allowed in this clinical study was 6 mg and was added to autologous bone at a 1:1 ratio. Autologous bone was added to the mixture if the volume of mixed graft was insufficient to fill the bone defect. Patients were followed 3, 6, and 12 months post-operatively. Each visit, a radiograph was taken for assessment. Visual analog scale (VAS), questionnaire for quality of life (SF-12 physical component summary [PCS], mental component summary [MCS]), and weight-bearing status were collected for functional outcome assessment. Drug safety was assessed by examining BMP-2 antibodies.

RESULTS

Of the 24 enrolled patients (mean age: 57 years), 15 (62.5 %), 2 (8.33 %), and 7 (29.17 %) presented atrophic nonunion, hypertrophic nonunion with deformity, and bone defect after fracture related infection, respectively. Thirteen patients had nonunion in the femur, 9 in the tibia, and 1 in the humerus and radius. The average amount of harvested autologous bone was 9.25 g and 4.96 mg of rhBMP-2. All 24 patients achieved union after 1-year follow up. The union rate was 95.83 % and 100 % at 6 and 12 months postoperatively, respectively. Preoperative SF-12 PCS (mean: 34.71) improved at 6 and 12 months postoperatively, respectively. Preoperative SF-12 MCS (mean: 42.89) improved 12 months postoperatively (49.13, p = 0.0338). Change of VAS was statistically significant 3 months postoperatively (p = 0.0012). No adverse effects or development of BMP-2 antibodies were observed.

CONCLUSION

BMP-2 combined with autogenous bone resulted in excellent radiographical and functional outcomes in a relatively small prospective series of patients with nonunion and bone defect, without adverse effects. Further investigations are necessary to support our finding and optimize treatment strategies in nonunion patients.

In vivo effects of cell seeding technique in an ex vivo regional gene therapy model for bone regeneration

When delivering cells on a scaffold to treat a bone defect, the cell seeding technique determines the number and distribution of cells within a scaffold, however the optimal technique has not been established. This study investigated if human adipose-derived stem cells (ASCs) transduced with a lentiviral vector to overexpress bone morphogenetic protein 2 (BMP-2) and loaded on a scaffold using dynamic orbital shaker could reduce the total cell dose required to heal a critical sized bone defect when compared with static seeding. Human ASCs were loaded onto a collagen/biphasic ceramic scaffold using static loading and dynamic orbital shaker techniques, compared with our labs standard loading technique, and implanted into femoral defects of nude rats. Both a low dose and standard dose of transduced cells were evaluated. Outcomes investigated included BMP-2 production, radiographic healing, micro-computerized tomography, histologic assessment, and biomechanical torsional testing. BMP-2 production was higher in the orbital shaker cohort compared with the static seeding cohort. No statistically significant differences were noted in radiographic, histomorphometric, and biomechanical outcomes between the low-dose static and dynamic seeding groups, however the standard-dose static seeding cohort had superior biomechanical properties. The standard-dose 5 million cell dose standard loading cohort had superior maximum torque and torsional stiffness on biomechanical testing. The use of orbital shaker technique was labor intensive and did not provide equivalent biomechanical results with the use of fewer cells.

Association of Poor Bone Quality with Pseudarthrosis and Poor Clinical Outcomes in Single-Level Instrumented Lumbar Arthrodesis Using Local Autologous Bone Graft

INTRODUCTION

Although osteoporosis and low bone mineral density is thought to lead to poor fusion outcomes, few studies have adequately addressed the correlation, and they were limited by small sample size at a single institution.

METHODS

We completed a secondary analysis of 182 patients enrolled at 26 spine centers across the United States in the EXO-SPINE FDA-approved clinical trial with 12-month CT-based fusion status determined by two independent, blinded radiologists. Using previously described CT-based techniques, we measured local and global Hounsfield units (HU) and examined the relationship with radiographic and clinical outcomes.

RESULTS

CT scans were available for review from 95 patients, with a mean age of 56.2 years and mean global density of 153.0 HU. No relationship was observed between HU and radiographic fusion status or clinical outcomes. Although 12% of patients had lumbar vertebral body HU measurements consistent with osteoporosis, this classification had no relation with fusion or clinical outcomes. Patients with pseudarthrosis had higher Oswestry Disability Index (22.2 vs. 16.6, P = 0.037) and back pain visual analog scale (7.0 vs. 4.9, P = 0.014) scores than patients with at least unilateral fusion at the 12-month follow-up.

DISCUSSION

In this large, multicenter study, lower vertebral body HU was not associated with worse fusion status after single-level instrumented posterolateral lumbar fusion using only local autologous bone graft. However, there was an association between radiographic fusion status and clinical outcomes, validating the importance of determining predictors of successful fusion. Assessment of fusion status with CT scans yielded a much lower fusion success rate with local bone graft than previously reported and may warrant additional investigation.

Liquefied capsules containing nanogrooved microdiscs and umbilical cord-derived cells for bone tissue engineering

Background

Surface topography has been shown to influence cell behavior and direct stromal cell differentiation into distinct lineages. Whereas this phenomenon has been verified in two-dimensional cultures, there is an urgent need for a thorough investigation of topography's role within a three-dimensional (3D) environment, as it better replicates the natural cellular environment.

Methods

A co-culture of Wharton's jelly-derived mesenchymal stem/stromal cells (WJ-MSCs) and human umbilical vein endothelial cells (HUVECs) was encapsulated in a 3D system consisting of a permselective liquefied environment containing freely dispersed spherical microparticles (spheres) or nanogrooved microdiscs (microdiscs). Microdiscs presenting 358 ± 23 nm grooves and 944 ± 49 nm ridges were produced via nanoimprinting of spherical polycaprolactone microparticles between water-soluble polyvinyl alcohol counter molds of nanogrooved templates. Spheres and microdiscs were cultured in vitro with umbilical cord-derived cells in a basal or osteogenic medium within liquefied capsules for 21 days.

Results

WJ-MSCs and HUVECs were successfully encapsulated within liquefied capsules containing spheres and microdiscs, ensuring high cellular viability. Results show an enhanced osteogenic differentiation in microdiscs compared to spheres, even in basal medium, evidenced by alkaline phosphatase activity and osteopontin expression.

Conclusions

This work suggests that the topographical features present in microdiscs induce the osteogenic differentiation of adhered WJ-MSCs along the contact guidance, without additional differentiation factors. The developed 3D bioencapsulation system comprising topographical features might be suitable for bone tissue engineering approaches with minimum in vitro manipulation.

Biofunctionalized hydrogel composed of genipin-crosslinked gelatin/hyaluronic acid incorporated with lyophilized platelet-rich fibrin for segmental bone defect repair

Segmental bone defects can arise from trauma, infection, metabolic bone disorders, or tumor removal. Hydrogels have gained attention in the field of bone regeneration due to their unique hydrophilic properties and the ability to customize their physical and chemical characteristics to serve as scaffolds and carriers for growth factors. However, the limited mechanical strength of hydrogels and the rapid release of active substances have hindered their clinical utility and therapeutic effectiveness. With ongoing advancements in material science, the development of injectable and biofunctionalized hydrogels holds great promise for addressing the challenges associated with segmental bone defects. In this study, we incorporated lyophilized platelet-rich fibrin (LPRF), which contains a multitude of growth factors, into a genipin-crosslinked gelatin/hyaluronic acid (GLT/HA-0.5 % GP) hydrogel to create an injectable and biofunctionalized composite material. Our findings demonstrate that this biofunctionalized hydrogel possesses optimal attributes for bone tissue engineering. Furthermore, results obtained from rabbit model with segmental tibial bone defects, indicate that the treatment with this biofunctionalized hydrogel resulted in increased new bone formation, as confirmed by imaging and histological analysis. From a translational perspective, this biofunctionalized hydrogel provides innovative and bioinspired capabilities that have the potential to enhance bone repair and regeneration in future clinical applications.

Three-dimensional volumetric assessment and stability of simultaneously placed implant following sinus floor augmentation with deproteinized human demineralized tooth matrix or deproteinized bovine bone mineral: a randomized controlled clinical trial

PURPOSE

This study aimed to analyze and compare three-dimensional volumetric bone changes and stability of simultaneously placed dental implants following sinus augmentation using deproteinized human demineralized tooth matrix (dpDTM) and deproteinized bovine bone mineral (DBBM).

METHODS

Twenty-four patients who required lateral maxillary sinus floor augmentation with simultaneous dental implant placement were randomly assigned to receive either dpDTM (n = 12) or DBBM (n = 12). Cone-beam computed tomography and resonance frequency analysis of implant stability were conducted immediately after surgery and 6 months postoperatively. Changes in the graft sinus floor and graft height volumes in the sagittal and coronal views, along with the implant stability quotient (ISQ), were analyzed and compared.

RESULTS

Volumetric graft alteration was comparable between dpDTM (120.33 ± 77.48 mm3) and DBBM (108.51 ± 65.15 mm3) (p = 0.690). Reduction in the average graft height was also comparable: dpDTM group ranged from - 0.59 to - 0.93 mm and the DBBM group ranged from - 0.55 to - 0.82 mm (p > 0.05) at most examined levels. However, greater reduction in the mesial-graft height occurred in the dpDTM group (- 1.08 ± 0.70 mm vs. -0.58 ± 0.39 mm, p = 0.04). The ISQ values increased similarly in both groups to reach 70 at 6 months.

CONCLUSION

dpDTM demonstrated comparable stability in graft volume and height during the healing process compared to DBBM and could serve as a viable alternative to DBBM for sinus floor augmentation with simultaneous implant placement.

Functionalized hydrogels as smart gene delivery systems to treat musculoskeletal disorders

Despite critical advances in regenerative medicine, the generation of definitive, reliable treatments for musculoskeletal diseases remains challenging. Gene therapy based on the delivery of therapeutic genetic sequences has strong value to offer effective, durable options to decisively manage such disorders. Furthermore, scaffold-mediated gene therapy provides powerful alternatives to overcome hurdles associated with classical gene therapy, allowing for the spatiotemporal delivery of candidate genes to sites of injury. Among the many scaffolds for musculoskeletal research, hydrogels raised increasing attention in addition to other potent systems (solid, hybrid scaffolds) due to their versatility and competence as drug and cell carriers in tissue engineering and wound dressing. Attractive functionalities of hydrogels for musculoskeletal therapy include their injectability, stimuli-responsiveness, self-healing, and nanocomposition that may further allow to upgrade of them as "intelligently" efficient and mechanically strong platforms, rather than as just inert vehicles. Such functionalized hydrogels may also be tuned to successfully transfer therapeutic genes in a minimally invasive manner in order to protect their cargos and allow for their long-term effects. In light of such features, this review focuses on functionalized hydrogels and demonstrates their competence for the treatment of musculoskeletal disorders using gene therapy procedures, from gene therapy principles to hydrogel functionalization methods and applications of hydrogel-mediated gene therapy for musculoskeletal disorders, while remaining challenges are being discussed in the perspective of translation in patients. STATEMENT OF SIGNIFICANCE: Despite advances in regenerative medicine, the generation of definitive, reliable treatments for musculoskeletal diseases remains challenging. Gene therapy has strong value in offering effective, durable options to decisively manage such disorders. Scaffold-mediated gene therapy provides powerful alternatives to overcome hurdles associated with classical gene therapy. Among many scaffolds for musculoskeletal research, hydrogels raised increasing attention. Functionalities including injectability, stimuli-responsiveness, and self-healing, tune them as "intelligently" efficient and mechanically strong platforms, rather than as just inert vehicles. This review introduces functionalized hydrogels for musculoskeletal disorder treatment using gene therapy procedures, from gene therapy principles to functionalized hydrogels and applications of hydrogel-mediated gene therapy for musculoskeletal disorders, while remaining challenges are discussed from the perspective of translation in patients.

Establishing a bone bank within a hospital setting in India: early insights from a tertiary care center in Northern India-a review article

When addressing bone defects resulting from trauma, infection, or tumors, the use of allogenic bone is often necessary. While autografts are considered the standard, they have limitations and can lead to donor site morbidity. Consequently, there has been exploration into the feasibility of utilizing allogenic bone and bone graft replacements. Allogenic bone transplants are acquired from donors following rigorous procurement, sterile processing, and donor screening procedures. To ensure the safe storage and effective utilization of allograft material, a bone banking system is employed. Establishing and managing an orthopedic bone bank, entails navigating complex legal and medical organizational aspects. This paper examines the establishment and operation of bone banks in India, drawing upon our first-hand experience in managing one at a tertiary care center in Northern India.Level of evidence: Level IV.

An Exploration of the Role of Osteoclast Lineage Cells in Bone Tissue Engineering

Bone defects because of age, trauma, and surgery, which are exacerbated by medication side effects and common diseases such as osteoporosis, diabetes, and rheumatoid arthritis, are a problem of epidemic scale. The present clinical standard for treating these defects includes autografts and allografts. Although both treatments can promote robust regenerative outcomes, they fail to strike a desirable balance of availability, side effect profile, consistent regenerative efficacy, and affordability. This difficulty has contributed to the rise of bone tissue engineering (BTE) as a potential avenue through which enhanced bone regeneration could be delivered. BTE is founded upon a paradigm of using biomaterials, bioactive factors, osteoblast lineage cells (ObLCs), and vascularization to cue deficient bone tissue into a state of regeneration. Despite promising preclinical results, BTE has had modest success in being translated into the clinical setting. One barrier has been the simplicity of its paradigm relative to the complexity of biological bone. Therefore, this paradigm must be critically examined and expanded to better account for this complexity. One potential avenue for this is a more detailed consideration of osteoclast lineage cells (OcLCs). Although these cells ostensibly oppose ObLCs and bone regeneration through their resorptive functions, a myriad of investigations have shed light on their potential to influence bone equilibrium in more complex ways through their interactions with both ObLCs and bone matrix. Most BTE research has not systematically evaluated their influence. Yet contrary to expectations associated with the paradigm, a selection of BTE investigations has demonstrated that this influence can enhance bone regeneration in certain contexts. In addition, much work has elucidated the role of many controllable scaffold parameters in both inhibiting and stimulating the activity of OcLCs in parallel to bone regeneration. Therefore, this review aims to detail and explore the implications of OcLCs in BTE and how they can be leveraged to improve upon the existing BTE paradigm.

A digital in situ bone augmentation workflow for reconstructing the alveolar ridge outline using a modified shell technique

The traditional shell technique is a practical method for augmenting horizontal and vertical alveolar bone defects. However, it has drawbacks, including increased morbidity in the donor site and imprecise harvesting of bone grafts. Instead of using a second surgical site, root areas at the defect site could be the in situ donor site. A digitally designed bone harvest guide was used for an in situ bone augmentation workflow, and the modified shell technique was planned and executed in the root area. This technique offered a controllable procedure which might enhance bone augmentation.

Comparative Effectiveness of an Autologous Dentin Matrix for Alveolar Ridge Preservation

An urgent issue is the preservation or reconstruction of the volume of bone tissue in planning and surgical treatment in the fields of medicine, such as traumatology, orthopedics, maxillofacial surgery and dentistry. After tooth extraction, resorption of the bone tissue of the alveolar crest of the jaws occurs, which must either be further eliminated by performing additional operations or using osteoplastic material for socket preservation at the extraction stage. Background and Objectives: The aim of the study was a comparative analysis of various osteoplastic materials used to preserve the volume of bone tissue in the preimplantation period. Materials and Methods: As part of the study, 80 patients were treated, who underwent socket preservation using xenografts, plasma enriched with growth factors, an autologous dentin matrix (ADM) and hydroxyapatite. Results: The results of the treatment 16 weeks after removal were comprehensively analyzed using a morphometric analysis of the bone's volume, cone beam tomography and morphological examination of burr biopsy specimens, as well as by determining the stability of the installed implant at different stages of treatment. Conclusions: The lowest level of bone tissue resorption according to the CBCT data was noted in the ADM and xenograft groups. It should be noted that the use of osteoplastic material in jaw surgery when reconstructing alveolar defects is an essential procedure for preventing the atrophy of bone tissue.

A Gelatin-Based Biomimetic Scaffold Promoting Osteogenic Differentiation of Adipose-Derived Mesenchymal Stem Cells

Background

In bone tissue engineering segment, numerous approaches have been investigated to address critically sized bone defects via 3D scaffolds, as the amount of autologous bone grafts are limited, accompanied with complications on harvesting. Moreover, the use of bone-marrow-derived stem cells is also a limiting factor owing to the invasive procedures involved and the low yield of stem cells. Hence, research is ongoing on the search for an ideal bone graft system promoting bone growth and regeneration.

Purpose of the Study

This study aims to develop a unique platform for tissue development via stem cell differentiation towards an osteogenic phenotype providing optimum biological cues for cell adhesion, differentiation and proliferation using biomimetic gelatin-based scaffolds. The use of adipose-derived mesenchymal stem cells in this study also offers an ideal approach for the development of an autologous bone graft.

Methods

A gelatin-vinyl acetate-based 3D scaffold system incorporating Bioglass was developed and the osteogenic differentiation of adipose-derived mesenchymal stem cells (ADMSCs) on the highly porous freeze-dried gelatin-vinyl acetate/ Bioglass scaffold (GB) system was analyzed. The physicochemical properties, cell proliferation and viability were investigated by seeding rat adipose tissue-derived mesenchymal stem cells (ADSCs) onto the scaffolds. The osteogenic differentiation potential of the ADMSC seeded GeVAc/bioglass system was assessed using calcium deposition assay and bone-related protein and genes and comparing with the 3D Gelatin vinyl acetate coppolymer (GeVAc) constructs.

Results and Conclusion

According to the findings, the 3D porous GeVAc/bioglass scaffold can be considered as a promising matrix for bone tissue regeneration and the 3D architecture supports the differentiation of the ADMSCs into osteoblast cells and enhances the production of mineralized bone matrix.

Computational models of bone fracture healing and applications: a review

Fracture healing is a very complex physiological process involving multiple events at different temporal and spatial scales, such as cell migration and tissue differentiation, in which mechanical stimuli and biochemical factors assume key roles. With the continuous improvement of computer technology in recent years, computer models have provided excellent solutions for studying the complex process of bone healing. These models not only provide profound insights into the mechanisms of fracture healing, but also have important implications for clinical treatment strategies. In this review, we first provide an overview of research in the field of computational models of fracture healing based on CiteSpace software, followed by a summary of recent advances, and a discussion of the limitations of these models and future directions for improvement. Finally, we provide a systematic summary of the application of computational models of fracture healing in three areas: bone tissue engineering, fixator optimization and clinical treatment strategies. The application of computational models of bone healing in clinical treatment is immature, but an inevitable trend, and as these models become more refined, their role in guiding clinical treatment will become more prominent.

Sustainably cultured coral scaffold supports human bone marrow mesenchymal stromal cell osteogenesis

The current gold standard grafting material is autologous bone due to its osteoinductive and osteoconductive properties. Autograft harvesting results in donors site morbidity. Coral scaffolds offer a natural autograft alternative, sharing the density and porosity of human bone. This study investigated the biocompatibility and osteogenic potential of a novel, sustainably grown Pocillopora scaffold with human bone marrow-derived mesenchymal stromal cells (MSCs). The coral-derived scaffold displays a highly textured topography, with concavities of uniform size and a high calcium carbonate content. Large scaffold samples exhibit compressive and diametral tensile strengths in the range of trabecular bone, with strengths likely increasing for smaller particulate samples. Following the in vitro seeding of MSCs adjacent to the scaffold, the MSCs remained viable, continued proliferating and metabolising, demonstrating biocompatibility. The seeded MSCs densely covered the coral scaffold with organized, aligned cultures with a fibroblastic morphology. In vivo coral scaffolds with MSCs supported earlier bone and blood vessel formation as compared to control constructs containing TCP-HA and MSCs. This work characterized a novel, sustainably grown coral scaffold that was biocompatible with MSCs and supports their in vivo osteogenic differentiation, advancing the current repertoire of biomaterials for bone grafting.

Spontaneous healing of hypertrophic pseudoarthrosis of pediatric mid shaft ulna with elastic stable intramedullary nailing in situ: A case report

Forearm fractures are the most common type of fractures in pediatric age. As children have excellent healing potential, fracture nonunion is a very uncommon complication. Elastic intramedullary nailing, a minimally invasive technique, is an excellent treatment modality for the unstable forearm shaft fractures in children, which can seldom lead to nonunion. Here, we present a case of hypertrophic pseudoarthrosis of mid shaft of ulna in a 13-year-old male, which healed spontaneously with elastic stable intramedullary nailing in situ.

Morbidity Associated With Distal Tibial Autograft Harvest

Distal tibial autograft harvesting has been studied in the past, but morbidity at the level of the donor site is unclear. The purpose of this retrospective review is to assess morbidity in distal tibial autograft harvesting associated with foot and ankle arthrodesis procedures. A retrospective analysis was performed utilizing patients treated in the last 13 years at a large, multicenter, academic, tertiary referral, research institution. Included patients were between the ages of 18 and 80 years old. One-hundred and seven patients (39 male; 68 female) underwent ipsilateral distal tibial bone graft (n = 110) harvesting to augment the index procedure. Patients were followed for an average of 11.2 months after surgery (Range: 1-73 months). The incidence rate of distal tibial stress fractures was 4.5%, with an overall postoperative complication rate of 8.2%. Overall, low complication rates associated with distal tibial autograft harvesting were found, supporting the use of the distal tibia as an appropriate site for autograft harvesting in foot and ankle surgery.

Delayed Orbital Floor Reconstruction Using Mirroring Technique and Patient-Specific Implants: Proof of Concept

Enophthalmos is a severe complication of primary reconstruction following orbital floor fractures, oncological resections, or maxillo-facial syndromes. The goal of secondary orbital reconstruction is to regain a symmetrical globe position to restore function and aesthetics. In this article, we present a method of computer-assisted orbital floor reconstruction using a mirroring technique and a custom-made titanium or high-density polyethylene mesh printed using computer-aided manufacturing techniques. This reconstructive protocol involves four steps: mirroring of the healthy orbit computer tomography files at the contralateral affected site, virtual design of a customized implant, computer-assisted manufacturing (CAM) of the implant using Direct Metal Laser Sintering (DMLS) or Computer Numerical Control (CNC) methods, and surgical insertion of the device. Clinical outcomes were assessed using 3dMD photogrammetry and computed tomography measures in 13 treated patients and compared to a control group treated with stock implants. An improvement of 3.04 mm (range 0.3-6 mm) in globe protrusion was obtained for the patients treated with patient-specific implants (PSI), and no major complications have been registered. The technique described here appears to be a viable method for correcting complex orbital floor defects needing delayed reconstruction.

Radiographic Fusion Outcomes for Trinity Cellular Based Allograft versus Local Bone in Posterolateral Lumbar Fusion

INTRODUCTION

Cellular-based autograft (CBA) is being used in posterolateral lumbar arthrodesis as a fusion supplementation alternative.

OBJECTIVE

To assess radiographic fusion in patients undergoing posterolateral lumbar fusion with unilateral Trinity CBA compared with contralateral local bone autograft as an internal control.

METHODS

A single surgeon's practice database was interrogated for consecutive patients undergoing primary posterolateral lumbar fusion with Trinity from 2018 to 2021. Patients had Trinity applied unilaterally, with local bone autograft applied contralaterally. Fusion was assessed postoperatively by using CT after 9 months. Demographics and patient-reported outcome measures were collected preoperatively and up to 12 months postoperatively.

RESULTS

Thirty-nine patients were included. There were 81 attempted fusion levels. Overall fusion rate, defined as bony bridging on at least one side of a given level for all levels fused, was 85.2% of patients. No statistically significant difference was observed in fusion rates between CBA versus local bone (79.0% versus 76.54% of levels attempted, respectively, P = 0.3527). Oswestry Disability Index improved by 3 months (P = 0.0152) and was maintained. Two patients required revision for symptomatic nonunion.

CONCLUSIONS

Similar radiographic fusion rates were achieved with Trinity and local bone. Trinity is a viable alternative to local bone in posterolateral lumbar fusion.

3D-printed nanohydroxyapatite/methylacrylylated silk fibroin scaffold for repairing rat skull defects

The repair of bone defects remains a major challenge in the clinic, and treatment requires bone grafts or bone replacement materials. Existing biomaterials have many limitations and cannot meet the various needs of clinical applications. To treat bone defects, we constructed a nanohydroxyapatite (nHA)/methylacrylylated silk fibroin (MASF) composite biological scaffold using photocurable 3D printing technology. In this study, scanning electron microscopy (SEM) was used to detect the changes in the morphological structure of the composite scaffold with different contents of nanohydroxyapatite, and FTIR was used to detect the functional groups and chemical bonds in the composite scaffold to determine the specific components of the scaffold. In in vitro experiments, bone marrow mesenchymal stem cells from SD rats were cocultured with scaffolds soaking solution, and the cytotoxicity, cell proliferation, Western blot analysis, Quantitative real-time PCR analysis, bone alkaline phosphatase activity and alizarin red staining of scaffolds were detected to determine the biocompatibility of scaffolds and the effect of promoting proliferation and osteogenesis of bone marrow mesenchymal stem cells in vitro. In the in vivo experiment, the skull defect was constructed by adult SD rats, and the scaffold was implanted into the skull defect site. After 4 weeks and 8 weeks of culture, the specific osteogenic effect of the scaffold in the skull defect site was detected by animal micro-CT, hematoxylin and eosin (HE) staining and Masson's staining. Through the analysis of the morphological structure of the scaffold, we found that the frame supported good retention of the lamellar structure of silk fibroin, when mixed with nHA, the surface of the stent was rougher, the cell contact area increased, and cell adhesion and lamellar microstructure for cell migration and proliferation of the microenvironment provided a better space. FTIR results showed that the scaffold completely retained the β -folded structure of silk fibroin, and the scaffold composite was present without obvious impurities. The staining results of live/dead cells showed that the constructed scaffolds had no significant cytotoxicity, and thw CCK-8 assay also showed that the constructed scaffolds had good biocompatibility. The results of osteogenic induction showed that the scaffold had good osteogenic induction ability. Moreover, the results also showed that the scaffold with a MASF: nHA ratio of 1: 0.5 (SFH) showed better osteogenic ability. The micro-CT and bone histometric results were consistent with the in vitro results after stent implantation, and there was more bone formation at the bone defect site in the SFH group.This research used photocurable 3D printing technology to successfully build an osteogenesis bracket. The results show that the constructed nHA/MASF biological composite material, has good biocompatibility and good osteogenesis function. At the same time, in the microenvironment, the material can also promote bone defect repair and can potentially be used as a bone defect filling material for bone regeneration applications.

Three Milliliters of Peripheral Blood Is Sufficient for Preparing Liquid Platelet-Rich Fibrin (PRF): An In Vitro Study

Platelet-rich fibrin (PRF) has assumed an important role in supporting tissue regeneration in different fields. To date, the standard protocol for liquid PRF requires at least 10 mL of peripheral blood. The present study aimed to analyze the composition, growth factor release, and effects on the cell proliferation of PRF samples produced using 3 mL vs. 10 mL of peripheral blood in vitro. Peripheral venous blood from six healthy donors was used to prepare liquid PRF using either 3 mL or 10 mL tubes. Three different centrifugation protocols were used according to the low-speed centrifugation concept. The cellular distribution was evaluated using immunohistology and automated cell count. ELISA was used to determine the release of different growth factors (EGF, TGF-β1, and PDGF) and interleukin 8 at different time points. Primary human osteoblasts (pOBs) were cultivated for 7 days using PRF-conditioned media acquired from either 3 mL or 10 mL of peripheral blood. The results showed that 3 mL of peripheral blood is sufficient to produce a liquid PRF concentrate similar to that acquired when using 10 mL blood. The concentrations of platelets and leukocytes were comparable regardless of the initial blood volume (3 mL vs. 10 mL). Similarly, the release of growth factors (EGF, TGF-β1, and PDGF) and interleukin 8 was often comparable in both groups over 7 days. The cultivation of pOBs using PRF-conditioned media showed a similar proliferation rate regardless of the initial blood volume. This proliferation rate was also similar to that of pOBs treated with 20% FBS-conditioned media. These findings validated the use of 3 mL of peripheral blood to generate liquid PRF matrices according to the low-speed centrifugation concept, which may open new application fields for research purposes such as in vivo experiments and clinical applications such as pediatric surgery.

Percutaneous elevation of proximal tibia depressed fractures using modified new instrument

Proximal tibia depression fracture often occur isolated or in conjunction with complex fracture presentations and elevation of such depression is required to retard arthritis in long term. Conventional open reduction by sub meniscal approach has many percutaneous alternatives from arthroscopy assisted reduction to balloon tibioplasty. Few authors even reported usage of PCL jig and percutaneous pins to elevate, while the primary author has previously described an instrument to elevate the depressed fragment percutaneously. With the shortcomings of the same instrument, authors have designed modifications in the same to address anterior and posterior extensions of depression without widening the metaphyseal window. In this article, we describe the size and concept of the modified design and its efficacy to address depression injuries.

Limitations and modifications in the clinical application of calcium sulfate

Calcium sulfate and calcium sulfate-based biomaterials have been widely used in non-load-bearing bone defects for hundreds of years due to their superior biocompatibility, biodegradability, and non-toxicity. However, lower compressive strength and rapid degradation rate are the main limitations in clinical applications. Excessive absorption causes a sharp increase in sulfate ion and calcium ion concentrations around the bone defect site, resulting in delayed wound healing and hypercalcemia. In addition, the space between calcium sulfate and the host bone, resulting from excessively rapid absorption, has adverse effects on bone healing or fusion techniques. This issue has been recognized and addressed. The lack of sufficient mechanical strength makes it challenging to use calcium sulfate and calcium sulfate-based biomaterials in load-bearing areas. To overcome these defects, the introduction of various inorganic additives, such as calcium carbonate, calcium phosphate, and calcium silicate, into calcium sulfate is an effective measure. Inorganic materials with different physical and chemical properties can greatly improve the properties of calcium sulfate composites. For example, the hydrolysis products of calcium carbonate are alkaline substances that can buffer the acidic environment caused by the degradation of calcium sulfate; calcium phosphate has poor degradation, which can effectively avoid the excessive absorption of calcium sulfate; and calcium silicate can promote the compressive strength and stimulate new bone formation. The purpose of this review is to review the poor properties of calcium sulfate and its complications in clinical application and to explore the effect of various inorganic additives on the physicochemical properties and biological properties of calcium sulfate.

Porcine Mandibular Bone Marrow-Derived Mesenchymal Stem Cell (BMSC)-Derived Extracellular Vesicles Can Promote the Osteogenic Differentiation Capacity of Porcine Tibial-Derived BMSCs

OBJECTIVE

Existing research suggests that bone marrow-derived mesenchymal stem cells (BMSCs) may promote endogenous bone repair. This may be through the secretion of factors that stimulate repair processes or directly through differentiation into osteoblast-progenitor cells. However, the osteogenic potential of BMSCs varies among different tissue sources (e.g., mandibular versus long BMSCs). The main aim of this study was to investigate the difference in osteogenic differentiation capacity between mandibular BMSCs (mBMSCs) and tibial BMSCs (tBMSCs).

MATERIALS AND METHODS

Bioinformatics analysis of the GSE81430 dataset taken from the Gene Expression Omnibus (GEO) database was performed using GEO2R. BMSCs were isolated from mandibular and tibial bone marrow tissue samples. Healthy pigs (n = 3) (registered at the State Office for Nature, Environment, and Consumer Protection, North Rhine-Westphalia (LANUV) 81-02.04.2020.A215) were used for this purpose. Cell morphology and osteogenic differentiation were evaluated in mBMSCs and tBMSCs. The expression levels of toll-like receptor 4 (TLR4) and nuclear transcription factor κB (NF-κB) were analyzed using quantitative polymerase chain reaction (qPCR) and Western blot (WB), respectively. In addition, mBMSC-derived extracellular vesicles (mBMSC-EVs) were gained and used as osteogenic stimuli for tBMSCs. Cell morphology and osteogenic differentiation capacity were assessed after mBMSC-EV stimulation.

RESULTS

Bioinformatic analysis indicated that the difference in the activation of the TLR4/NF-κB pathway was more pronounced compared to all other examined genes. Specifically, this demonstrated significant downregulation, whereas only 5-7 upregulated genes displayed significant variances. The mBMSC group showed stronger osteogenic differentiation capacity compared to the tBMSC group, confirmed via ALP, ARS, and von Kossa staining. Furthermore, qPCR and WB analysis revealed a significant decrease in the expression of the TLR4/NF-κB pathway in the mBMSC group compared to the tBMSC group (TLR4 fold changes: mBMSCs vs. tBMSCs p < 0.05; NF-κB fold changes: mBMSCs vs. tBMSCs p < 0.05). The osteogenic differentiation capacity was enhanced, and qPCR and WB analysis revealed a significant decrease in the expression of TLR4 and NF-κB in the tBMSC group with mBMSC-EVs added compared to tBMSCs alone (TLR4 fold changes: p < 0.05; NF-κB fold changes: p < 0.05).

CONCLUSION

Our results indicate that mBMSC-EVs can promote the osteogenic differentiation of tBMSCs in vitro. The results also provide insights into the osteogenic mechanism of mBMSCs via TLR4/NF-κB signaling pathway activation. This discovery promises a fresh perspective on the treatment of bone fractures or malunions, potentially offering a novel therapeutic method.

Pain and Complications Following Bone Marrow Aspirate Concentrate Harvested From the Iliac Crest in Foot and Ankle Surgery

BACKGROUND

Autologous bone graft is the gold standard in orthopedics, with the iliac crest the most common harvest site. In an attempt to minimize morbidity with open bone graft harvest from the iliac crest and still maintain the benefit of collecting and transplanting live cells and growth factors, bone marrow aspirate concentrate (BMAC) from the iliac crest has become increasingly popular. However, any harvest procedure can potentially cause pain and complications. The purpose of this study was to evaluate the safety and complications of BMAC from the iliac crest for use in foot and ankle fusion procedures.

METHODS

A retrospective chart review was performed on all patients who underwent BMAC harvest from the iliac crest with their foot or ankle procedure by 1 of 4 fellowship-trained surgeons (2014-2017) with a minimum of 6-month follow-up. Patients were evaluated for complications, pain, and functional limitation secondary to the harvest. The final outcome follow-up was conducted using a specifically designed telephone questionnaire to assess patient satisfaction. A total of 55 patients were included, with a median age of 58 years (range 31-81 years) and 69% were women.

RESULTS

Out of 55 patients, 52 (94.5%) reported good to excellent results, and satisfaction with the procedure at the time of the questionnaire. Three patients reported persistent complications and some element of dissatisfaction after 6 months. Some patients reported transient complications (hematomas and numbness) that eventually resolved. Fifty percent of patients reported some element of immediate post-operative pain. However, at the time of final follow-up, only 2 reported persistent pain at the harvest site lasting up to 6 months, but it was not activity limiting.

CONCLUSION

BMAC harvest is a safe procedure with a high rate of patient satisfaction and minimal morbidity.

LEVELS OF EVIDENCE

Level IV: Case series.

Bone Graft Substitutes-What Are My Options?

We examine the range of available bone graft substitutes often used in nonunion and malunion surgery of the upper extremity. Synthetic materials such as calcium sulfate, beta-calcium phosphate ceramics, hydroxyapatite, bioactive glass, and 3D printed materials are discussed. We delve into the advantages, disadvantages, and clinical applications for each, considering factors such as biocompatibility, osteoconductivity, mechanical strength, and resorption rates. This review provides upper extremity surgeons with insights into the available array of bone graft substitutes. We hope that the reviews helps in the decision-making process to achieve optimal outcomes when treating nonunion and malunion of the upper extremity.

The Role of Vasculature and Angiogenic Strategies in Bone Regeneration

Bone regeneration is a complex process that involves various growth factors, cell types, and extracellular matrix components. A crucial aspect of this process is the formation of a vascular network, which provides essential nutrients and oxygen and promotes osteogenesis by interacting with bone tissue. This review provides a comprehensive discussion of the critical role of vasculature in bone regeneration and the applications of angiogenic strategies, from conventional to cutting-edge methodologies. Recent research has shifted towards innovative bone tissue engineering strategies that integrate vascularized bone complexes, recognizing the significant role of vasculature in bone regeneration. The article begins by examining the role of angiogenesis in bone regeneration. It then introduces various in vitro and in vivo applications that have achieved accelerated bone regeneration through angiogenesis to highlight recent advances in bone tissue engineering. This review also identifies remaining challenges and outlines future directions for research in vascularized bone regeneration.

Safety and Reoperation Rates in Non-instrumented Lumbar Fusion Surgery: Secondary Report From a Randomized Controlled Trial of ABM/P-15 vs Allograft With Minimum 5 years Follow-Up

STUDY DESIGN

Randomized controlled trial with minimum of 5-years follow-up.

OBJECTIVE

The purpose of this study is to evaluate the peri- and postoperative complications rates, ectopic bone migration, and reoperation rates, and secondly evaluate the 5-year patient reported outcomes (PROs), in patients treated with decompression and non-instrumented posterolateral fusion with ABM/P-15 or allograft.

METHODS

Patients with degenerative spondylolisthesis were enrolled in a Randomized Clinical Trial and randomized 1:1 to either ABM/P-15 or allograft bone. Patient Reported Outcomes were collected at 5-year follow-up, and patients were invited to a clinical follow-up including a computed tomography scan (CT) to evaluate signs of osteolysis, ectopic bone formation, and bone migration.

RESULTS

Of 101 subjects enrolled in the primary study, 83 patients were available for the 5-year follow-up. We found a statistically significant difference in back pain and Oswestry Disability Index between groups. Fifty-eight patients agreed to participate in the CT study. Sixty percentage in the ABM/P-15 group vs 30% in the allograft group was classified as fused (P = .037). There were no differences in complications, reoperation-, or infection rates between the 2 groups. We found 2 patients with migration of graft material. Both patients were asymptomatic at minimum 5-year follow-up.

CONCLUSION

Our study indicated that complication rates are no higher in patients treated with ABM/P-15 than allograft. We found significantly higher fusion rates in the AMB/P-15 group than in the allograft group, and patients in the ABM/P-15 group reported less back pain and lower disability score at 5-year follow-up.

Sustainable Sources of Raw Materials for Additive Manufacturing of Bone-Substituting Biomaterials

The need for sustainable development has never been more urgent, as the world continues to struggle with environmental challenges, such as climate change, pollution, and dwindling natural resources. The use of renewable and recycled waste materials as a source of raw materials for biomaterials and tissue engineering is a promising avenue for sustainable development. Although tissue engineering has rapidly developed, the challenges associated with fulfilling the increasing demand for bone substitutes and implants remain unresolved, particularly as the global population ages. This review provides an overview of waste materials, such as eggshells, seashells, fish residues, and agricultural biomass, that can be transformed into biomaterials for bone tissue engineering. While the development of recycled metals is in its early stages, the use of probiotics and renewable polymers to improve the biofunctionalities of bone implants is highlighted. Despite the advances of additive manufacturing (AM), studies on AM waste-derived bone-substitutes are limited. It is foreseeable that AM technologies can provide a more sustainable alternative to manufacturing biomaterials and implants. The preliminary results of eggshell and seashell-derived calcium phosphate and rice husk ash-derived silica can likely pave the way for more advanced applications of AM waste-derived biomaterials for sustainably addressing several unmet clinical applications.

Case report: Corpectomy and iliac crest bone autograft as treatment for a vertebral plasma cell tumor in a dachshund dog

A 7-year-old, 7.5 kg, female spayed dachshund dog presented to a veterinary teaching hospital after being referred for lameness and the inability to urinate. The dog presented as weakly ambulatory paraparetic with intact pain perception. Computed tomographic (CT) imaging showed ventral bony lysis and periosteal proliferation of the L3 vertebra, consistent with a plasma cell tumor. A corpectomy of the L3 vertebra was performed and subsequently stabilized with autogenous cortico-cancellous iliac crest bone staves, autogenous cancellous bone, and bilaterally placed locking plates [String of Pearls (SOP®), Orthomed]. The dog recovered well, with no decrease in neurologic status overnight, and continued to improve until discharge. Upon a recheck exam at 4 weeks postoperatively, the dog appeared neurologically improved with only mild ambulatory proprioceptive ataxia of the hind limbs. This case demonstrates that the transposition of a non-vascularized iliac crest autogenous bone graft with stabilization via SOP® plates and screws can be used in the management of dogs with vertebral plasma cell tumors and should be considered as a surgical option in similarly affected cases.

Biodistribution of lentiviral transduced adipose-derived stem cells for "ex-vivo" regional gene therapy for bone repair

Ex-vivo gene therapy has been shown to be an effective method for treating bone defects in pre-clinical models. As gene therapy is explored as a potential treatment option in humans, an assessment of the safety profile becomes an important next step. The purpose of this study was to evaluate the biodistribution of viral particles at the defect site and various internal organs in a rat femoral defect model after implantation of human ASCs transduced with lentivirus (LV) with two-step transcriptional activation (TSTA) of bone morphogenetic protein-2 (LV-TSTA-BMP-2). Animals were sacrificed at 4-, 14-, 56-, and 84-days post implantation. The defects were treated with either a standard dose (SD) of 5 million cells or a high dose (HD) of 15 million cells to simulate a supratherapeutic dose. Treatment groups included (1) SD LV-TSTA-BMP-2 (2) HD LV-TSTA-BMP-2, (3) SD LV-TSTA-GFP (4) HD LV-TSTA-GFP and (5) SD nontransduced cells. The viral load at the defect site and ten organs was assessed at each timepoint. Histology of all organs, ipsilateral tibia, and femur were evaluated at each timepoint. There were nearly undetectable levels of LV-TSTA-BMP-2 transduced cells at the defect site at 84-days and no pathologic changes in any organ at all timepoints. In conclusion, human ASCs transduced with a lentiviral vector were both safe and effective in treating critical size bone defects in a pre-clinical model. These results suggest that regional gene therapy using lentiviral vector to treat bone defects has the potential to be a safe and effective treatment in humans.