Bone Marrow Aspirate Concentrate in Animal Long Bone Healing: An Analysis of Basic Science Evidence

Vascular restoration through local delivery of angiogenic factors stimulates bone regeneration in critical size defects

Critical size bone defects represent a significant challenge worldwide, often leading to persistent pain and physical disability that profoundly impact patients' quality of life and mental well-being. To address the intricate and complex repair processes involved in these defects, we performed single-cell RNA sequencing and revealed notable shifts in cellular populations within regenerative tissue. Specifically, we observed a decrease in progenitor lineage cells and endothelial cells, coupled with an increase in fibrotic lineage cells and pro-inflammatory cells within regenerative tissue. Furthermore, our analysis of differentially expressed genes and associated signaling pathway at the single-cell level highlighted impaired angiogenesis as a central pathway in critical size bone defects, notably influenced by reduction of Spp1 and Cxcl12 expression. This deficiency was particularly pronounced in progenitor lineage cells and myeloid lineage cells, underscoring its significance in the regeneration process. In response to these findings, we developed an innovative approach to enhance bone regeneration in critical size bone defects. Our fabrication process involves the integration of electrospun PCL fibers with electrosprayed PLGA microspheres carrying Spp1 and Cxcl12. This design allows for the gradual release of Spp1 and Cxcl12 in vitro and in vivo. To evaluate the efficacy of our approach, we locally applied PCL scaffolds loaded with Spp1 and Cxcl12 in a murine model of critical size bone defects. Our results demonstrated restored angiogenesis, accelerated bone regeneration, alleviated pain responses and improved mobility in treated mice.

Enriched mesoporous bioactive glass scaffolds as bone substitutes in critical diaphyseal bone defects in rabbits

In the field of orthopedic surgery, there is an increasing need for the development of bone replacement materials for the treatment of bone defects. One of the main focuses of biomaterials engineering are advanced bioceramics like mesoporous bioactive glasses (MBG´s). The present study compared the new bone formation after 12 weeks of implantation of MBG scaffolds with composition 82,5SiO2-10CaO-5P2O5-x 2.5SrO alone (MBGA), enriched with osteostatin, an osteoinductive peptide, (MBGO) or enriched with bone marrow aspirate (MBGB) in a long bone critical defect in radius bone of adult New Zealand rabbits. New bone formation from the MBG scaffold groups was compared to the gold standard defect filled with iliac crest autograft and to the unfilled defect. Radiographic follow-up was performed at 2, 6, and 12 weeks, and microCT and histologic examination were performed at 12 weeks. X-Ray study showed the highest bone formation scores in the group with the defect filled with autograft, followed by the MBGB group, in addition, the microCT study showed that bone within defect scores (BV/TV) were higher in the MBGO group. This difference could be explained by the higher density of newly formed bone in the osteostatin enriched MBG scaffold group. Therefore, MBG scaffold alone and enriched with osteostatin or bone marrow aspirate increase bone formation compared to defect unfilled, being higher in the osteostatin group. The present results showed the potential to treat critical bone defects by combining MBGs with osteogenic peptides such as osteostatin, with good prospects for translation into clinical practice. STATEMENT OF SIGNIFICANCE: Treatment of bone defects without the capacity for self-repair is a global problem in the field of Orthopedic Surgery, as evidenced by the fact that in the U.S alone it affects approximately 100,000 patients per year. The gold standard of treatment in these cases is the autograft, but its use has limitations both in the amount of graft to be obtained and in the morbidity produced in the donor site. In the field of materials engineering, there is a growing interest in the development of a bone substitute equivalent. Mesoporous bioactive glass (MBG´s) scaffolds with three-dimensional architecture have shown great potential for use as a bone substitutes. The osteostatin-enriched Sr-MBG used in this long bone defect in rabbit radius bone in vivo study showed an increase in bone formation close to autograft, which makes us think that it may be an option to consider as bone substitute.

Biologic therapies in stress fractures: Current concepts

Stress fractures, a common overuse injury in physically active individuals, present a significant challenge for athletes and military personnel. Patients who sustain stress fractures have demanding training regimes where periods of rest and immobilisation have unacceptable negative consequences on sports goals and finances. Aside from being an overuse injury, there are various contributing risk factors that put certain individuals at risk of a stress fracture. The main two being nutritional deficiencies and hormonal variations, which have significant effects on bone metabolism and turnover. Historically, treatment of stress fractures focused on conservative strategies such as rest and immobilisation. Calcium and vitamin D deficiencies have been closely linked to stress fractures and so over time supplementation has also played a role in treatment. With the introduction of biologics into orthopaedics, newer treatment strategies have been applied to accelerate fracture healing and perhaps improve fracture callus quality. If such therapies can reduce time spent away from sport and activity, it would be ideal for treating stress fractures. This article aims to offer insights into the evolving landscape of stress fracture management. It investigates the pre-clinical evidence and available published clinical applications. Though fracture healing is well understood, the role of biologics for fracture healing is still indeterminate. Available literature for the use of biologic therapies in stress fractures are restricted and most reports have used biologics as a supplement to surgical fixation in subjects in studies that lack control groups. Randomised control trials have been proposed and registered by a few groups, with results awaited. Assessing individuals for risk factors, addressing hormonal imbalances and nutritional deficiencies seems like an effective approach to addressing the burden of stress fractures. We await better designed trials and studies to accurately determine the clinical benefit of adding biologics to the management of these injuries.

A new method regulates bone fracture tissue exosome lncRNA-mRNA to promote mesenchymal stem cell proliferation and migration

Post-injury adaptation (PIA) is a simple and convenient method to promote bone healing, but its mechanism is unclear. This study was to discuss the role of fracture site tissue exosomes lncRNAs-mRNAs networks on PIA promoting bone mesenchymal stem cells (BMSCs) proliferation and migration. Firstly, the effects of PIA accelerating BMSCs proliferation and migration were confirmed by rat fracture model and bone fracture environment in vitro. Besides, the fracture site tissue exosomes were isolated and authenticated. Then the tissue exosomes were the key factor in PIA promoting BMSCs proliferation and migration authenticated by in vitro and in vivo experiments. The high throughput sequencing and RT-PCR were used to analyze the tissue exosomes lncRNAs-mRNAs networks. It was found that PIA treatment upregulated 118 lncRNAs, 295 mRNAs, and downregulated 111 lncRNAs, 2706 mRNAs in tissue exosomes. A total 12,211 genes were the target genes. Akt1, Actb and Uba52 were the hub mRNAs in tissue exosomes. In additions, tissue-derived exosomes of PIA treated rats upregulated 49 genes, 3 lncRNAs and downregulated 28 genes, 1 lncRNA in BMSCs. Kif11 was the hub gene. Overall, PIA promoted BMSCs proliferation and migration in the early stage of fracture healing, which was closely related to the fracture site tissue exosomes. Akt1, Actb and Uba52 were the hub mRNAs in the exosomes. Besides, Kif11 might be the key gene in BMSC regulated by tissue-derived exosomes of PIA treated rats.

The 50 Most Cited Publications on Concentrated Bone Marrow Aspirate with Application in Orthopaedic Surgery

Concentrated bone marrow aspirate (cBMA) has garnered widespread and increasing attention in recent years. We aimed to characterize the most influential articles in cBMA research while clarifying controversies surrounding its use and clinical efficacy and identifying important areas on which to focus future research efforts. The Science Citation Index Expanded subsection of the Web of Science Core Collection was systematically searched to identify the top 50 most cited publications on orthopaedic cBMA research. Publication and study characteristics were extracted, and Spearman's correlations were calculated to assess the relationship between citation data and level of evidence. The top 50 articles were published between the years 1996 and 2018, with 58% published in the year 2010 or later. Of the 29 studies for which level of evidence was assessed, the majority were Level IV (24, 83%). Twenty-one articles (42%) were classified as basic science or translational (9 cell culture, 8 animal study, and 4 using human blood samples). Application to treat cartilage defects was the most common focus of studies (17 studies, 34%), followed by analysis of cBMA composition (14 studies, 28%). No correlation was found between rank, citation rate, or year of publication and level of evidence. The most influential articles on cBMA are recent and consist of a majority low level of evidence studies. Cohort studies were the most common study type among the top 50 most cited articles, while basic science articles were relatively less common. These results suggest a rapidly evolving field with the potential to better explain inconsistent clinical results with improved understanding and documentation of basic science concepts in addition to large-scale, prospective clinical trials. Orthobiologics especially cBMA holds great promise for the future, and higher level clinical trials will help better define the best clinical uses for this treatment.

Bone Marrow Stromal Cells Sorted by Semiconducting Polymer Nanodots for Bone Repair

The use of bone marrow stromal cells (BMSCs) for bone defect repair has shown great promise due to their differentiation potential. However, isolating the BMSCs from various cell types within the bone marrow remains challenging. To tackle this issue, we utilized semiconducting polymer dots (Pdots) as markers to select the BMSCs within a specific time frame. The therapeutic efficacy of the obtained Pdot-labeled BMSCs was assessed in a bone defect model. Initially, we evaluated the binding capacity of the Pdots with four different types of cells present in the bone marrow including BMSCs, osteoblasts, macrophages, and vascular endothelial cells, in vitro. Notably, BMSCs showed the most rapid uptake of the Pdots, being labeled within only one h of coculture, while other cells took four h to become labeled. Moreover, by colocalizing the Pdots with Prrx1, Sca-1, OSX, F480, and CD105 in the bone marrow cells of monocortical tibial defect (MTD) mice in vivo, we determined the proportions of BMSCs, macrophages, and vascular endothelial cells among all labeled cells from 1 to 8 h after the Pdots injection. It was found that BMSCs have the highest proportion (92%) among all labeled cells extracted after 1 h of Pdots injection. The therapeutic efficacy of the obtained Pdots-labeled BMSCs (1 h) was assessed in a bone defect model. Results showed that the new bone accrual was significantly increased in the treatment of Pdots-labeled BMSCs compared to the bone marrow cell-treated group. Our study revealed that BMSCs screened by the Pdots could improve bone defect repair, suggesting a promising application of the Pdots in bone healing.

Osteochondral Allografts in Knee Surgery: Narrative Review of Evidence to Date

Knee articular cartilage defects can result in significant pain and loss of function in active patients. Osteochondral allograft (OCA) transplantation offers a single-stage solution to address large chondral and osteochondral defects by resurfacing focal cartilage defects with mature hyaline cartilage. To date, OCA transplantation of the knee has demonstrated excellent clinical outcomes and long-term survivorship. However, significant variability still exists among clinicians with regard to parameters for graft acceptance, surgical technique, and rehabilitation. Technologies to optimize graft viability during storage, improve osseous integration of the allograft, and shorten recovery timelines after surgery continue to evolve. The purpose of this review is to examine the latest evidence on treatment indications, graft storage and surgical technique, patient outcomes and survivorship, and rehabilitation after surgery.

Novel Techniques and Future Perspective for Investigating Critical-Size Bone Defects

A critical-size bone defect is a challenging clinical problem in which a gap between bone ends will not heal and will become a nonunion. The current treatment is to harvest and transplant an autologous bone graft to facilitate bone bridging. To develop less invasive but equally effective treatment options, one needs to first have a comprehensive understanding of the bone healing process. Therefore, it is imperative to leverage the most advanced technologies to elucidate the fundamental concepts of the bone healing process and develop innovative therapeutic strategies to bridge the nonunion gap. In this review, we first discuss the current animal models to study critical-size bone defects. Then, we focus on four novel analytic techniques and discuss their strengths and limitations. These four technologies are mass cytometry (CyTOF) for enhanced cellular analysis, imaging mass cytometry (IMC) for enhanced tissue special imaging, single-cell RNA sequencing (scRNA-seq) for detailed transcriptome analysis, and Luminex assays for comprehensive protein secretome analysis. With this new understanding of the healing of critical-size bone defects, novel methods of diagnosis and treatment will emerge.

Impact of the Process Variables on the Yield of Mesenchymal Stromal Cells from Bone Marrow Aspirate Concentrate

Human bone marrow (BM) has been highlighted as a promising source of mesenchymal stromal cells (MSCs) containing various growth factors and cytokines that can be potentially utilized in regenerative procedures involving cartilage and bone. However, the proportion of MSCs in the nucleated cell population of BM is only around 0.001% to 0.01% thereby making the harvesting and processing technique crucial for obtaining optimal results upon its use in various regenerative processes. Although several studies in the literature have given encouraging results on the utility of BM aspiration concentrate (BMAC) in various regenerative procedures, there is a lack of consensus concerning the harvesting variables such as choice of anesthetic agent to be used, site of harvest, size of the syringe to be used, anticoagulant of choice, and processing variables such as centrifugation time, and speed. In this review article, we aim to discuss the variables in the harvesting and processing technique of BMAC and their impact on the yield of MSCs in the final concentrate obtained from them.

Current Modalities for Fracture Healing Enhancement

Previously, most fractures have been treated through bone reduction and immobilization. With an increase in the patients' need for an early return to their normal function, development in surgical techniques and materials have accelerated. However, delayed union or non-union of the fracture site sometimes inhibits immediate return to normal life. To enhance fracture healing, diverse materials and methods have been developed. This is a review on the current modalities of fracture healing enhancement, which aims to provide a comprehensive knowledge regarding fracture healing for researchers and health practitioners.

Applications of Polymeric Composites in Bone Tissue Engineering and Jawbone Regeneration

Polymer-based composites are a group of biomaterials that exert synergic and combined activity. There are multiple reported uses of these composites in multiple biomedical areas, such as drug carriers, in wound dressings, and, more prominently, in tissue engineering and regenerative medicine. Bone grafting is a promising field in the use of polymeric composites, as this is the second most frequently transplanted organ in the United States. Advances in novel biomaterials, such as polymeric composites, will undoubtedly be of great aid in bone tissue engineering and regeneration. In this paper, a general view of bone structure and polymeric composites will be given, discussing the potential role of these components in bone tissue. Moreover, the most relevant jawbone and maxillofacial applications of polymeric composites will be revised in this article, collecting the main knowledge about this topic and emphasizing the need of further clinical studies in humans.

Topical Review: Bone Marrow Aspirate Concentrate and Its Clinical Use in Foot and Ankle Surgery

Bone marrow aspirate concentrate (BMAC) is now commonly used in orthopedic surgery. Animal studies showed promising results for cartilage, bone, and soft tissue healing; however, many of these outcomes have yet to be translated to human models. While there has been an increase in the use of BMAC in foot and ankle procedures, the associated clinical evidence is limited. The purpose of this review is to analyze the existing literature in order to evaluate the safety and efficacy of BMAC in foot and ankle surgery.

Reamer-irrigator-aspirate versus bone marrow aspirate concentrate for osteoprogenitor cell retention and osteoinductive protein release on cancellous bone

Bone defects often require operative intervention with the use of bone graft. Two sources of autologous bone graft include reamer-irrigator-aspirate (RIA) and bone marrow aspirate concentrate (BMC). Osteoprogenitor cells and osteoconductive proteins have been identified in both sources. This study collected samples of these cells and proteins from a canine model and cultured them on human cancellous allograft bone blocks. Findings suggest that BMC may be preferred for indications that allow for delivery via injection, saturation of the patient's tissues, or an implanted scaffold, whereas RIA may be preferred when the biologic augment is delivered as a scaffold or graft.

A three-dimensional computed tomography study to determine the ideal method for fluoroscopically-guided bone marrow aspiration from the iliac crest

Bone marrow aspiration (BMA) through the iliac crest is potentially unsafe due to the vicinity of neurovascular structures in the greater sciatic notch. Our objective was to investigate the safety of a recently described BMA technique, specifically a trajectory from the posterior superior iliac spine (PSIS) to the anterior inferior iliac spine (AIIS). We conducted a chart review of 260 patients, analyzing three-dimensional reconstructed computed tomography images of the pelvis and sacrum to validate that this new approach offers a wide safety margin from the greater sciatic notch. Analysis of three-dimensional computed tomography scans demonstrated that the PSIS to AIIS trajectory never crossed the greater sciatic notch. The trajectory was noted to be at least one cm away from the greater sciatic notch in all measurements. The new trajectory entered the PSIS at 25.29 ± 4.34° (left side) and 24.93 ± 4.15° (right side) cephalad from the transverse plane, and 24.58 ± 4.99° (left side) and 24.56 ± 4.67° (right side) lateral from the mid-sagittal plane. The area of bone marrow encountered with the new approach was approximately 22.5 cm2. Utilizing the same CT scans, the trajectory from the traditional approach crossed the greater sciatic notch in all scans, highlighting the potential for violating the greater sciatic notch boundary and damaging important neurovascular structures. Statistically significant sex-related differences were identified in needle trajectory angles for both approaches. We conclude that based on this three-dimensional computed tomography study, a trajectory from the PSIS to the AIIS for BMA may offer a wide safety margin from the greater sciatic notch.

Navicular Stress Fractures

Navicular stress fractures are multifactorial injuries due to chronic overload on the navicular, particularly in young athletes. The navicular is subject to unique stresses and has a complex blood supply, making it susceptible to stress fractures and potentially delayed union or nonunion. Expeditious diagnosis is critical to prevent a delay in treatment and a poor outcome. Advanced imaging is essential in making the diagnosis and monitoring healing. Both nonsurgical and surgical treatments have demonstrated good results. Nonsurgical management consists of a period of immobilization and nonweight bearing, and surgical management typically involves open reduction and internal fixation. Patients need to be appropriately counseled regarding expectations for these challenging injuries.

Autologous bone marrow aspirate concentrate (BMAC) for treatment of keratocystic odontogenic tumour (KCOT)-a case report

Management of keratocystic odontogenic tumor (KCOT) has always remained a conundrum due to its aggressive behavior, indicating wide resection. Achieving an esthetically and functionally acceptable reconstruction remains a challenge. Herein, we present a novel and less invasive technique for the treatment of KCOT. A 55-year-old female presenting with pain in the lower jaw for the past 3 months was diagnosed with a large KCOT extending from 35 to 47 region. CT images revealed buccal and lingual cortical bone erosion. Management was done in two stages: cyst curettage and chemical cauterization, followed by application of Bone Marrow Aspirate Concentrate (BMAC) with a delay of two months, to increase the thickness of eroded cortical bone. On follow-up at one year, ossification of the defect was observed. BMAC is a cocktail of mesenchymal stromal cells, hematopoietic stem cells, fibroblasts, mononuclear cells, macrophages, endothelial cells, progenitor cells, growth factors and cytokines. BMAC cocktail provide an anti-inflammatory, anti-fibrotic, anti-apoptotic, and immunomodulatory environment. Autologous platelet rich plasma provides various growth factors (TGF-β, PDGF, EGF, HGF, NGF, IGF-1) and cytokines. Addition of PRP in BMAC cocktail enhance the regeneration of tissues, where PRP act as a functional regenerative scaffold for cell integration, proliferation, and differentiation that can expedite macroscale musculoskeletal tissue healing. Autologous BMAC with corticocancellous bone acts as an osteoconductive scaffold capable of regenerating the large bone defect created by the curettage of KCOT.

Stroke treatment: Is exosome therapy superior to stem cell therapy?

Stroke is one of the most common causes of disability and death, and currently, ideal clinical treatment is lacking. Stem cell transplantation is a widely-used treatment approach for stroke. When compared with other types of stem cells, bone marrow mesenchymal stem cells (BMSCs) have been widely studied because of their many advantages. The paracrine effect is the primary mechanism for stem cells to play their role, and exosomes play an essential role in the paracrine effect. When compared with cell therapy, cell-free exosome therapy can prevent many risks and difficulties, and therefore, represents a promising and novel approach for treatment. In this study, we reviewed the research progress in the application of BMSCs-derived exosomes (BMSCs-exos) and BMSCs in the treatment of stroke. In addition, the advantages and disadvantages of cell therapy and cell-free exosome therapy were described, and the possible factors that hinder the introduction of these two treatments into the clinic were analyzed. Furthermore, we reviewed the current optimization methods of cell therapy and cell-free exosome therapy. Taken together, we hypothesize that cell-free exosome therapy will have excellent research prospects in the future, and therefore, it is worth further exploring. There are still some issues that need to be further addressed. For example, differences between the in vivo microenvironment and in vitro culture conditions will affect the paracrine effect of stem cells. Most importantly, we believe that more preclinical and clinical design studies are required to compare the efficacy of stem cells and exosomes.

Vascular Supply and Bone Marrow Concentrate for the Improvement of Allograft in Bone Defects: A Comparative In Vivo Study

BACKGROUND

Surgical repair of critical-sized bone defects still remains a big challenge in orthopedic surgery. Biological enhancement, such as growth factors or cells, can stimulate a better outcome in bone regeneration driven by well-established treatments such as allogenic bone graft. However, despite the surgical options available, correct healing can be slowed down or compromised by insufficient vascular supply to the injured site.

MATERIALS AND METHODS

In this pilot study, critical size bone defects in rabbit radius were treated with allograft bone, in combination with vascular bundle and autologous bone marrow concentrate seeded onto a commercial collagen scaffold. Microtomographical, histological and immunohistochemical assessments were performed to evaluate allograft integration and bone regeneration.

RESULTS

Results showed that the surgical deviation of vascular bundle in the bone graft, regardless from the addition of bone marrow concentrate, promote the onset of healing process at short experimental times (8 wk) in comparison with the other groups, enhancing graft integration.

CONCLUSION

The surgical procedure tested stimulates bone healing at early times, preserving native bone architecture, and can be easily combined with biological adjuvant.

Epidemiology, Clinical Assessments, and Current Treatments of Nonunions

PURPOSE OF REVIEW

The failure of bony union following a fracture, termed a fracture nonunion, has severe patient morbidity and economic consequences. This review describes current consensuses and future directions of investigation for determining why, detecting when, and effective treatment if this complication occurs.

RECENT FINDINGS

Current nonunion investigation is emphasizing an expanded understanding of the biology of healing. This has led to assessments of the immune environment, multiple cytokines and morphogenetic factors, and the role of skeletogenic stem cells in the development of nonunion. Detecting biological markers and other objective diagnostic criteria is also a current objective of nonunion research. Treatment approaches in the near future will likely be dominated by the development of specific adjunct therapies to the nonunion surgical management, which will be informed by an expanded mechanistic understanding of nonunion biology. Current consensus among orthopedists is that improved diagnosis and treatment of nonunion hinges first on discoveries at the bench side with later translation to the clinic.

Two-Stage Revision Anterior Cruciate Ligament Reconstruction: A Systematic Review of Bone Graft Options for Tunnel Augmentation

BACKGROUND

No consensus is available regarding the optimal choice of bone graft material for bone tunnel augmentation in revision anterior cruciate ligament (ACL) surgery.

PURPOSE

To compare the outcomes of different bone graft materials for staged revision ACL reconstruction.

STUDY DESIGN

Systematic review.

METHODS

A systematic review using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed. PubMed, EMBASE, and the Cochrane Library were queried through use of the terms anterior cruciate ligament and revision to identify all studies reporting outcomes of bone tunnel grafting in 2-stage revision ACL reconstruction. Data extracted included indications for 2-stage surgery, surgical technique, graft material, time between surgeries, rehabilitation protocols, physical examination findings, patient-reported outcomes, and radiographic and histologic findings.

RESULTS

The analysis included 7 studies with a total of 234 patients. The primary outcome in 2 studies was graft incorporation (mean follow-up, 8.8 months), whereas the other 5 studies reported clinical outcomes with follow-up mean ± SD of 4.2 ± 2.1 years. The indication for bone grafting and between-stage protocol varied among studies. Autograft was used in 4 studies: iliac crest bone autograft (ICBG, n = 3) and tibial bone autograft (TBA, n = 1). In 2 studies, the authors investigated the outcomes of allograft: allograft bone matrix (ABM) and allograft bone chips (AC). Finally, 1 study compared ICBG to a synthetic bone substitute. Radiographic evaluation of bone graft integration after the first stage was reported in 4 studies, with an average duration of 4.9 months. In 4 studies, the authors reported the time interval between first and second surgeries, with an average of 6.1 months for ICBG compared with 8.7 months for allogenic and synthetic grafts. Revision ACL graft failure rates were reported by 5 studies, including 1 study with ABM (6.1%), 1 study with AC (8.3%), 1 study with TBA (0%), and 2 studies with ICBG (0% and 2%).

CONCLUSION

The indications for staged ACL reconstruction and the rehabilitation protocol between stages need to be clearly established. The available data indicate that autograft for bone tunnel grafting in 2-stage ACL revision may be associated with a lower risk of revision ACL reconstruction graft failure compared with allograft bone.

The top three unanswered questions in the management of open fractures

Despite improvements in treatment strategies and emphasis on preventative measures, the management of open fractures continues to be a challenging endeavor for orthopaedic surgeons. Deep infections, delayed healing, and nonunion continue to be problematic complications associated with these devastating injuries. There remain many unanswered clinical questions regarding the management of these injuries and how the various aspects of care can be further optimized. There continues to be a paucity of evidence regarding how infection can best be treated and prevented, how to reliability predict bone healing/nonunion, and how bone healing can be best augmented in the setting of open fractures and their potential nonunions. This review aims to assess the current literature on these top unanswered questions and discuss the gaps in evidence that may be filled with future studies.

The history of bone marrow in orthopaedic surgery (part I trauma): trepanning, bone marrow injection in damage control resuscitation, and bone marrow aspiration to heal fractures

PURPOSE

One of the oldest procedures performed by man is trepanning of the bone and yet it was only in the last 40 years that bone marrow aspiration has been used to treat nonunion disorders.

MATERIAL AND METHODS

These advances were possible due to improvements in instruments and in techniques to make holes in the bone, an history that began with skull trephinations around 8000-10,000 years ago, and continued with sternum bone marrow injection for trauma resuscitation in the beginning of the twentieth century; this procedure had improved at the beginning of the twenty-first century to allow pelvis bone marrow aspiration for the treatment of nonunion.

RESULTS

Trephined skulls from antiquity have been found in many parts of world, showing that trephining was ancient and widespread. Beginning with Neolithic period and the pre-Columbian Andean civilizations, the authors have traced the development of this surgical skill by describing the various surgical tools used to perform holes in the skull. These tools (trephines or trepan) were proposed at the end of the nineteenth century to study the bone marrow. At the beginning of the twentieth century, the sternum became the center of interest for the "in vivo" study of the bone marrow and the fluid injection in the sternum's bone marrow was described for resuscitation from shock during the World War II. With the introduction of plastic catheters and improved cannulation techniques, the need for intraosseous infusion as an alternative route for intravenous access diminished and sometimes abandoned. However, during the mid-1980s, James Orlowski allowed renaissance of the use of intraosseous infusion for paediatric resuscitation. Since then, this technique has become widespread and is now recognized as an alternative to intravenous access in adult emergencies; particularly, the intraosseous access has received class IIA recommendation from the Advanced Trauma Life Support program supported by the American College of Surgeons Committee on Trauma and bone marrow infusion is now recommended for "Damage Control" resuscitation. Although the pelvis bone contains half of the body's marrow volume, it was only in 1950 that the pelvis was proposed as a source for bone marrow aspiration and bone marrow-derived mesenchymal stem cells to improve healing of fractures.

CONCLUSION

It will be many years before doing holes in the bone as orthopaedic trauma procedure will be relegated to the annals of history.

Emerging Options for Biologic Enhancement of Stress Fracture Healing in Athletes

In an era of continual single-sport specialization and year-round training, overuse injuries, including stress injuries of bone, are increasingly common. These injuries can be season- or even career-ending. For many elite and professional athletes, the traditional treatment strategy of immobilization and extended rest from sports participation is often not practical or acceptable. An understanding of modern strategies for evaluating and treating stress fractures is paramount for maintaining athletic participation and optimal athletic performance. This begins with the ability to categorize and stratify bony stress injuries by both severity and risk of fracture progression. Surgical procedures such as open reduction and internal fixation or intramedullary fixation with possible bone grafting remain the standard of care for chronic or severe stress fractures. However, emerging techniques to augment the biologic environment are a minimally invasive adjunct for stimulating and supporting bone healing in elite-level athletes to optimize bone health, expedite recovery, and decrease the risk of nonunion or catastrophic fracture.

Tendon-to-Bone Healing in a Rat Extra-articular Bone Tunnel Model: A Comparison of Fresh Autologous Bone Marrow and Bone Marrow-Derived Mesenchymal Stem Cells

BACKGROUND

Despite widespread acceptance of fresh autologous bone marrow (BM) for use in clinical practice, limited information exists to analyze if tendon-to-bone healing could be accelerated with local use of fresh autologous BM.

PURPOSE

To investigate the effect of fresh autologous BM on tendon-to-bone healing with a novel rat model.

STUDY DESIGN

Controlled laboratory study.

METHODS

An extra-articular bone tunnel was created and filled with an autologous tendon graft in skeletally mature Sprague-Dawley rats (N = 60). They were then randomly divided into 3 groups: BM group (injection of fresh autologous BM into the tendon-bone interface, n = 20), BM-derived mesenchymal stem cell (BMSC) group (injection of allogenic cultured BMSCs, n = 20), and the control group (tendon-bone interface without injection of BM or BMSCs, n = 20). Biomechanical, histological, and immunohistochemical analyses were performed at 2 and 6 weeks after surgery.

RESULTS

The BM group showed a relatively well-organized and dense connective tissue interface with better orientation of collagen fibers as compared with the BMSC group. At 2 weeks, the tendon-bone interface tissue thickness of the BMSC group was 140 ± 25 μm (mean ± SEM), which was significantly greater than the BM group (58 ± 15 μm). The BM group showed fewer M1 macrophages at the tendon-bone interface at 2 and 6 weeks (P < .001). In contrast, there were more M2 macrophages at the interface in the BM group 2 and 6 weeks postoperatively when compared with controls and the BMSC group (P < .001). Biomechanical tests revealed significantly higher stiffness in the BM group versus the control and BMSC groups at 2 and 6 weeks after surgery (P < .05). Load to failure showed similar trends to stiffness.

CONCLUSION

These findings indicate that local delivery of fresh autologous BM enhances tendon-to-bone healing better than the alternative treatments in this study. This effect may be partially due to the observed modulation of inflammatory processes, especially in M2 macrophage polarization.

CLINICAL RELEVANCE

Fresh autologous BM could be a treatment option for this disorder.

Conditioning of myoblast secretome using mesenchymal stem/stromal cell spheroids improves bone repair

Local muscle loss associated with open fractures remains an obstacle to functional recovery and bone healing. Muscle cells secrete bioactive myokines that elicit autocrine and paracrine effects and initiate signaling pathways for regenerating damaged muscle and bone. Mesenchymal stem/stromal cells (MSCs) are under investigation for the regeneration of both muscle and bone through their potent secretome. Compared to monodisperse cells, MSC spheroids exhibit a more complex secretome with heightened therapeutic potential. We hypothesized that the osteogenic potential of myokines would be enhanced when myoblasts were exposed to the MSC spheroid secretome. Conditioned media from MSC spheroids increased osteogenic response of MC3T3 pre-osteoblasts compared to myokines from L6 myoblasts alone. This effect was synergistically enhanced when conditioned media of MSC spheroids was serially delivered to myoblasts and then osteoprogenitor cells in vitro. We then delivered myoblast-stimulated conditioned media in the presence or absence of syngeneic rat bone marrow stromal cells (rBMSCs) from alginate hydrogels to a rat critical-sized segmental defect. We observed increased bone formation in defects treated with conditioned media compared to rBMSCs alone, while bone formation was greatest in defects treated with both conditioned media and rBMSCs over 12 weeks. This foundational study demonstrates a novel approach for capitalizing on the paracrine signaling of muscle cells to promote bone repair and provides additional evidence of the synergistic interaction between muscle and bone.

Quantitation of progenitor cell populations and growth factors after bone marrow aspirate concentration

Background

The number of Mesenchymal Stem/Stromal Cells (MSCs) in the human bone marrow (BM) is small compared to other cell types. BM aspirate concentration (BMAC) may be used to increase numbers of MSCs, but the composition of MSC subpopulations and growth factors after processing are unknown. The purpose of this study was to assess the enrichment of stem/progenitor cells and growth factors in BM aspirate by two different commercial concentration devices versus standard BM aspiration.

Methods

120 mL of BM was aspirated from the iliac crest of 10 male donors. Each sample was processed simultaneously by either Emcyte GenesisCS^® (Emcyte) or Harvest SmartPReP2 BMAC (Harvest) devices and compared to untreated BM aspirate. Samples were analyzed with multicolor flow cytometry for cellular viability and expression of stem/progenitor cells markers. Stem/progenitor cell content was verified by quantification of colony forming unit-fibroblasts (CFU-F). Platelet, red blood cell and total nucleated cell (TNC) content were determined using an automated hematology analyzer. Growth factors contents were analyzed with protein quantification assays. Statistical analyses were performed by ANOVA analysis of variance followed by Tukey’s multiple comparison test or Wilcoxon matched-pairs signed rank test with p < 0.05 for significance.

Results

Cell viability after processing was approximately 90% in all groups. Compared to control, both devices significantly enriched TNCs and platelets, as well as the CD45−CD73+ and CD45−CD73+CD90+ cell populations. Further, Harvest significantly concentrated CD45−CD10+, CD45−CD29+, CD45−CD90+, CD45−CD105+, CD45−CD119+ cells, and CD45dimCD90+CD271+ MSCs, whereas Emcyte significantly enriched CD45dimCD44+CD271+ MSCs. BM concentration also increased the numbers of CFU-F, platelet-derived growth factor, vascular endothelial growth factor, macrophage colony-stimulating factor, interleukin-1b, VCAM-1 and total protein. Neither system concentrated red blood cells, hematopoietic stem cells or bone morphogenetic proteins.

Conclusion

This data could contribute to the development of BMAC quality control assays as both BMAC systems concentrated platelets, growth factors and non-hematopoietic stem cell subpopulations with distinct phenotypes without loss of cell viability when compared to unprocessed BM.

Electronic supplementary material

The online version of this article (10.1186/s12967-019-1866-7) contains supplementary material, which is available to authorized users.

Bone marrow aspirate concentrate with cancellous allograft versus iliac crest bone graft in the treatment of long bone nonunions

Objectives:

The purpose of this study was to compare bone marrow aspirate concentrate (BMAC) with cancellous allograft to iliac crest bone graft (ICBG) in the treatment of long bone nonunions.

Design:

Retrospective cohort study.

Setting:

A single level I trauma center.

Patients:

26 patients with long bone diaphyseal or metaphyseal nonunions with defects >2 mm and treated with open repair and BMAC, compared to 25 patients with long bone diaphyseal or metaphyseal nonunions with defects >2 mm and treated with open repair and ICBG.

Intervention:

Open repair of long bone nonunion using either autologous ICBG or BMAC with cancellous allograft.

Main outcome measure:

Nonunion healing, radiographically measured by the modified Radiographic Union Score for Tibia (mRUST) score. Secondary outcomes included risk factors associated with failed repair.

Results:

The union rates for the BMAC and ICBG cohorts were 75% and 78%, respectively (P = .8). Infection was the only risk factor of statistical significance for failure.

Conclusion:

In this study, we found no significant difference in union rate for long bone nonunions treated with ICBG or BMAC with allograft. BMAC and allograft led to 75% successful healing in this series. Given the heterogeneity of the control group and loss to follow-up, further prospective investigation should be conducted to more rigorously compare BMAC to ICBG for nonunion treatment.

Level of evidence:

III, retrospective cohort.

Bone Marrow Aspirate Concentrate Does Not Improve Osseous Integration of Osteochondral Allografts for the Treatment of Chondral Defects in the Knee at 6 and 12 Months: A Comparative Magnetic Resonance Imaging Analysis

BACKGROUND

Poor osseous integration after fresh osteochondral allograft transplantation (OCA) may be associated with graft subsidence and subchondral bone collapse after implantation. The augmentation of OCA with bone marrow aspirate concentrate (BMAC) has been hypothesized to improve osseous incorporation of the implanted allograft.

PURPOSE

To evaluate the effect of autogenous BMAC treatment on osseous integration at the graft-host bony interface after OCA.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective review of patients treated with OCA+BMAC or OCA alone for full-thickness chondral defects of the distal femur from March 2015 to December 2016 was conducted. Seventeen knees treated with OCA+BMAC and 16 knees treated with OCA alone underwent magnetic resonance imaging (MRI) in the early postoperative phase (mean, 6 months). Eighteen knees treated with OCA+BMAC and 16 knees treated with OCA alone underwent MRI in the late postoperative phase (mean, 12 months). Bone, cartilage, and ancillary features on MRI were graded using the Osteochondral Allograft MRI Scoring System (OCAMRISS) by a musculoskeletal radiologist blinded to the patient's history and treatment.

RESULTS

There were no significant differences in the demographics or lesion characteristics between treatment groups in either postoperative phase. In the early postoperative phase, the mean OCAMRISS bone score was 3.0 ± 0.7 and 3.3 ± 0.7 for the OCA+BMAC group and OCA alone group, respectively ( P = .76); 71% (OCA+BMAC) and 81% (OCA alone) of MRI scans demonstrated discernible clefts at the graft-host junction ( P = .69), and 41% (OCA+BMAC) and 25% (OCA alone) of MRI scans demonstrated cystic changes at the graft and graft-host junction ( P = .46). In the late postoperative phase, the mean OCAMRISS bone score was 2.7 ± 0.8 and 2.9 ± 0.8 for the OCA+BMAC group and OCA alone group, respectively ( P = .97); 44% (OCA+BMAC) and 63% (OCA alone) of MRI scans demonstrated discernible clefts at the graft-host junction ( P = .33), and 50% (OCA+BMAC) and 31% (OCA alone) of MRI scans demonstrated the presence of cystic changes at the graft and graft-host junction ( P = .32). The mean OCAMRISS cartilage, ancillary, and total scores were not significantly different between groups in either postoperative phase.

CONCLUSION

OCA augmented with BMAC was not associated with improved osseous integration; decreased cystic changes; or other bone, cartilage, and ancillary feature changes compared with OCA alone.

Orthobiologics for Bone Healing

Orthobiologics are a group of biological materials and substrates that promote bone, ligament, muscle, and tendon healing. These substances include bone autograft, bone allograft, demineralized bone matrix, bone graft substitutes, bone marrow aspirate concentrate, platelet-rich plasma, bone morphogenetic proteins, platelet-derived growth factor, parathyroid hormone, and vitamin D and calcium. Properties of orthobiologics in bone healing include osteoconduction, osteoinduction, and osteogenesis. This article discusses the important properties of orthobiologics in bone healing, many of the orthobiologics currently available for bone healing, the related literature, their current clinical uses in sports medicine, and systemic factors that inhibit bone healing.

Down-regulation of LGR6 promotes bone fracture recovery using bone marrow stromal cells

OBJECTIVE

The Leucine-rich repeat-containing G-protein coupled receptor 6 (LGR6) is a well-known marker of stem cells. In present study, we aimed to further explore the effects of LGR6 on promoting osteogenic differentiation of bone marrow stromal cells (BMSCs) and bone healing.

METHODS

Flow cytometry assay was used to determine the expression of BMSCs surface markers, and western blot was performed to detect the LGR6 protein expression. The osteogenic differentiation of BMSCs was qualified using ALP and ARS staining. Protein expression of osteogenic genes (ALP, Collagen I, Runx2 and OCN) were evaluated using western blot. In vivo, BMSCs transfected with sh-LGR6 or LGR6 cDNA were injected into the fracture site to establish rat fracture healing model. X-ray system and hematoxylin-eosin (HE) staining were conducted to observe the fracture recovery. Biomechanical test was performed to detect the changes of maximum load, elastic modules and bone mineral density.

RESULTS

In BMSCS, CD90 and CD44 were positively expressed, while CD11b was negatively expressed. Expression level of LGR6 gradually decreased with the osteogenic differentiation of BMSCs. The osteogenic genes expression level during the osteogenic differentiation significantly increased with the down-regulation of LGR6. In vivo, 8 weeks after injection, rats treated with LGR6 knocked-down BMSCs showed increased number of fibroblasts. Maximum load, elastic modulus and the bone mineral density were enhanced with the knocking-down of LGR6.

CONCLUSION

Inhibition of LGR6 promoted the osteogenic differentiation of BMSCs in vitro. Moreover, transplantation of LGR6-knockout BMSCs in rat models contributes to a better recovery after the fracture.

Safety and Effectiveness of Talus Subchondroplasty and Bone Marrow Aspirate Concentrate for the Treatment of Osteochondral Defects of the Talus

Eleven patients with symptomatic talus osteochondral defects who underwent subchondroplasty with bone marrow aspirate concentrate injection were retrospectively reviewed. Foot and Ankle Outcome Score and visual analog scale pain score were recorded preoperatively and at the 1-year postoperative visit. The mean osteochondral defect size was 1.3×1.4 cm. The weight-bearing visual analog scale pain score improved from a mean of 7.8 to 1.8, and the Foot and Ankle Outcome Score improved from a mean of 67.1 to 89.6. At 1-year follow-up, 10 patients reported they would have the procedure again. Subchondroplasty and bone marrow aspirate concentrate injection offered good pain relief for talus osteochondral defects. The procedure allows immediate weight bearing postoperatively and does not compromise future treatments. [Orthopedics. 2018; 41(5):e734-e737.].

Pseudarthrosis of the Calcaneus: Advantages of Regenerative Medicine in the Management of a Rare Entity, A Case Report and Review of Literature

Background:

The follow-up of calcaneal fractures has shown that they are difficult to manage and lead to multiple complications such as malunion and subtalar osteoarthritis. Pseudarthrosis of the calcaneus is an extremely rare complication, which was described in the literature through case reports.

In the existing literature, only seven studies, including thirteen patients have reported the nonunion. However, to the best of our knowledge, no study elucidates the role of new techniques of regenerative medicine such as Bone Marrow Concentrates (BMC) or Platelet Rich Plasma (PRP) in the management.

Methods:

We report a case of a patient with a pseudarthrosis after a calcaneal fracture treated with BMC injection in the non-union site, without the need for surgical approach.

Results:

Four months after treatment, the patient was ambulant without support and was completely pain-free. Moreover, after one year the radiological follow up by CT scan showed a satisfactory filling of the non union.

Conclusion:

In one case, we try to highlight the advantage of our therapeutic alternatives, which are having a good union while avoiding the complications of surgical approaches and without sacrificing the subtalar joint when it is possible.

Critical-Size Bone Defects: Is There a Consensus for Diagnosis and Treatment?

There is a significant burden of disease associated with bone defects, and their management is challenging. These injuries have a profound clinical and economic impact, and outcomes are limited by high rates of complication and reoperation, as well as poor functional outcomes. There remains a lack of consensus around definitions, reliable models, and best practices for the surgical management of bone defects. The current state of the literature on bone defects is reviewed here, with a focus on defining critical-size bone defect, the use of the induced membrane technique, the role of biologics, and the management of infected bone defects.

Current perspectives on biological approaches for osteoarthritis

Musculoskeletal injuries that disrupt the structure and function of diarthrodial joints can cause permanent biomechanical alterations and lead to a more severe, chronic condition. Despite advancements that have been made to restore tissue function and delay the need for joint replacement, there are currently no disease-modifying therapies for osteoarthritis (OA). To reduce the risk of OA, innovative preventive medicine approaches have been developed over the last decade to treat the underlying pathology. Several biological approaches are promising treatment modalities for various stages of OA owing to their minimally invasive nature and actively dynamic physiological mechanisms that attenuate tissue degradation and inflammatory responses. Individualized growth factor and cytokine therapies, tissue-engineered biomaterials, and cell-based therapies have revolutionary potential for orthopedic applications; however, the paucity of standardization and categorization of biological components and their counterparts has made it difficult to determine their clinical and biological efficacy. Cell-based therapies and tissue-engineered biologics have become lucrative in sports medicine and orthopedics; nonetheless, there is a continued effort to produce a biological treatment modality tailored to target intra-articular structures that recapitulates tissue function. Advanced development of these biological treatment modalities will potentially optimize tissue healing, regeneration, and joint preservation strategies. Therefore, the purpose of this paper is to review current concepts on several biological treatment approaches for OA.

Bone Marrow Aspirate Concentrate and Its Uses in the Foot and Ankle

Bone marrow aspirate has been used for the adjunctive treatment of numerous pathologic conditions in orthopedics. Viable cells are found in aspiration from many different anatomic regions of the body. Concentration of these cells has been shown to improve healing due to the increased number of certain important cells. This article discusses the mechanisms involved and reviews the literature.

The Components of Bone and What They Can Teach Us about Regeneration

The problem of bone regeneration has engaged both physicians and scientists since the beginning of medicine. Not only can bone heal itself following most injuries, but when it does, the regenerated tissue is often indistinguishable from healthy bone. Problems arise, however, when bone does not heal properly, or when new tissue is needed, such as when two vertebrae are required to fuse to stabilize adjacent spine segments. Despite centuries of research, such procedures still require improved therapeutic methods to be devised. Autologous bone harvesting and grafting is currently still the accepted benchmark, despite drawbacks for clinicians and patients that include limited amounts, donor site morbidity, and variable quality. The necessity for an alternative to this "gold standard" has given rise to a bone-graft and substitute industry, with its central conundrum: what is the best way to regenerate bone? In this review, we dissect bone anatomy to summarize our current understanding of its constituents. We then look at how various components have been employed to improve bone regeneration. Evolving strategies for bone regeneration are then considered.

Biological Facet of Segmental Bone Loss Reconstruction

The management of long bone defects continues to be associated with significant challenges for optimum and timely bone repair. When bone grafting is needed, essential parameters to be addressed include adequate volume, optimum density, and structural capacity as well as potent biological properties. Although the autologous iliac crest bone graft remains the gold standard, its reduced availability and donor site morbidity have made the clinicians to seek for other alternative options. Reamer irrigator aspirator graft with materials used as graft expanders along with inductive molecules and cellular augmentation constitute the current trend for optimum bone regeneration. This article presents the contemporary thinking of the biological facet of segmental bone loss reconstruction.

Role of Bone Marrow Aspirate in Orthopedic Trauma

Bone marrow aspirate grafting entails mesenchymal stem cell-containing bone marrow harvesting and injection into a fracture site to promote bone formation. Although the use of bone marrow aspirate in orthopedic trauma is not widespread, an increasing number of studies are reporting clinical success. Advantages of using bone marrow aspirate are that it is readily obtainable, has low harvest morbidity, and can be easily and quickly injected. However, no universally accepted role for its use exists. Future studies directly comparing bone marrow aspirate with conventional techniques are needed to define its role in the treatment of orthopedic trauma patients.

Chipping and lengthening over nailing technique for femoral shaft nonunion with shortening

PURPOSE

Chipping and lengthening over nailing (CLON) technique was developed to treat femoral shaft nonunion with shortening more than 10 mm. The purpose of the current retrospective case series was to clarify the effectiveness of the CLON technique on the femoral shaft nonunion following intramedullary nailing.

METHODS

Clinical and radiological outcomes in the patients receiving operative treatment for femoral shaft nonunion between August 2012 and December 2016 were retrospectively reviewed using the Refractory Fracture Data Registry at the authors' institution. The CLON technique was indicated for patients with the femoral shaft nonunion with shortening more than 10 mm.

RESULTS

Five patients with median follow-up of 32 months (range, 14 to 50 months) were included in this study. All patients achieved bone union at the median of 8 months after the CLON technique. The median limb length discrepancy was 2.0 mm at the most recent follow-up.

CONCLUSIONS

The present study demonstrated that the CLON technique for femoral shaft nonunion may be the first choice as operative treatment for femoral shaft nonunion with shortening more than 10 mm.

Early loss of subchondral bone following microfracture is counteracted by bone marrow aspirate in a translational model of osteochondral repair

Microfracture of cartilage defects may induce alterations of the subchondral bone in the mid- and long-term, yet very little is known about their onset. Possibly, these changes may be avoided by an enhanced microfracture technique with additional application of bone marrow aspirate. In this study, full-thickness chondral defects in the knee joints of minipigs were either treated with (1) debridement down to the subchondral bone plate alone, (2) debridement with microfracture, or (3) microfracture with additional application of bone marrow aspirate. At 4 weeks after microfracture, the loss of subchondral bone below the defects largely exceeded the original microfracture holes. Of note, a significant increase of osteoclast density was identified in defects treated with microfracture alone compared with debridement only. Both changes were significantly counteracted by the adjunct treatment with bone marrow. Debridement and microfracture without or with bone marrow were equivalent regarding the early cartilage repair. These data suggest that microfracture induced a substantial early resorption of the subchondral bone and also highlight the potential value of bone marrow aspirate as an adjunct to counteract these alterations. Clinical studies are warranted to further elucidate early events of osteochondral repair and the effect of enhanced microfracture techniques.

Tarsal navicular stress fractures

PURPOSE OF REVIEW

Navicular stress fractures are common in athletes and management is debated. This article will review the evaluation and management of navicular stress fractures.

RECENT FINDINGS

Various operative and non-operative adjunctive treatment modalities are reviewed including the relevance of vitamin D levels, use of shock wave therapy and bone marrow aspirate concentrate (BMAC), and administration of teriparatide. Surgical treatment may be associated with earlier return to sports. The author's preferred treatment algorithm with corresponding images is presented which allows for safe and rapid return to activities in the athletic patient. Future research is needed in evaluating the preventative effects of vitamin D and use of other adjunctive treatments to increase the healing rates of this fracture.

Bone Marrow Aspirate Concentrate for Bone Healing in Foot and Ankle Surgery

Autologous bone marrow aspirate concentrate (BMAC) has become a popular orthobiologic to augment bone healing. The potential benefit comes from osteoprogenitor cells and growth factors that can lead to new bone formation in the setting of foot and ankle arthrodesis procedures. BMAC has an excellent safety record and has demonstrated efficacy in animal models of bone healing. Although scant, the literature on the use of BMAC in foot and ankle surgery does demonstrate promise for this orthobiologic adjuvant.