A systematic review of the clinical applications and complications of bone marrow aspirate concentrate in management of bone defects and nonunions

Clinical management and innovation in fracture non-union

INTRODUCTION

With the introduction and continuous improvement in operative fracture fixation, even the most severe bone fractures can be treated with a high rate of successful healing. However, healing complications can occur and when healing fails over prolonged time, the outcome is termed a fracture non-union. Non-union is generally believed to develop due to inadequate fixation, underlying host-related factors, or infection. Despite the advancements in fracture fixation and infection management, there is still a clear need for earlier diagnosis, improved prediction of healing outcomes and innovation in the treatment of non-union.

AREAS COVERED

This review provides a detailed description of non-union from a clinical perspective, including the state of the art in diagnosis, treatment, and currently available biomaterials and orthobiologics.Subsequently, recent translational development from the biological, mechanical, and infection research fields are presented, including the latest in smart implants, osteoinductive materials, and in silico modeling.

EXPERT OPINION

The first challenge for future innovations is to refine and to identify new clinical factors for the proper definition, diagnosis, and treatment of non-union. However, integration of in vitro, in vivo, and in silico research will enable a comprehensive understanding of non-union causes and correlations, leading to the development of more effective treatments.

A case series utilizing bone marrow aspirate concentrate, cancellous bone autograft, platelet-rich plasma and autologous fibrin for the treatment of femur nonunions

Aim: To assess the efficacy of a bioregenerative scaffold derived from bone marrow aspirate, cancellous bone autograft, platelet-rich plasma and autologous fibrin in treating supracondylar femur nonunions. Methods & materials: Three patients with nonunions following multiple surgical failures underwent bone stabilization and the application of a novel bioregenerative scaffold. x-rays and subjective scales were collected before surgery and at 6, 12 and 24 months post-surgery. Results: All nonunions exhibited healing with sufficient callus formation, as confirmed radiologically. After 6 months, all patients resumed full weight-bearing walking without pain. Statistical analysis showed improvements in all scales compared with pre-surgical values. Conclusion: This method presents itself as an option for treating supracondylar femur nonunions following multiple surgical failures.

Platelet-Rich Plasma Lysate Enhances the Osteogenic Differentiation of Adipose-Derived Stem Cells

ABSTRACT

Adipose-derived stem cells (ADSCs) have become an accepted source of cells in bone tissue engineering. This study aimed to investigate whether platelet-rich plasma (PRP) lysate can replace traditional fetal bovine serum as a culture medium with the enhanced proliferation and osteogenic potential of ADSCs. We divided the experiment into 5 groups where the ADSCs were cultured in an osteogenic medium containing 2.5%, 5%, 7.5%, and 10% PRP lysate with 10% fetal bovine serum as the control group. The cell proliferation, alkaline phosphatase (ALP) activity, ALP stain, alizarin red stain, osteocalcin (OCN) protein expression, and osteogenic-specific gene expression were analyzed and compared among these groups. The outcome showed that all PRP lysate-treated groups had good ALP stain and ALP activity performance. Better alizarin red stains were found in the 2.5%, 5%, and 7.5% PRP lysate groups. The 2.5% and 5% PRP lysate groups showed superior results in OCN quantitative polymerase chain reaction, whereas the 5% and 7.5% PRP lysate groups showed higher OCN protein expressions. Early RUNX2 (Runt-related transcription factor 2 () genes were the most expressed in the 5% PRP lysate group, followed by the 2.5% PRP lysate group, and then the 7.5% PRP lysate group. Thus, we concluded that 5% PRP lysate seemed to provide the optimal effect on enhancing the osteogenic potential of ADSCs. Platelet-rich plasma lysate-treated ADSCs were considered to be a good cell source for application in treating nonunion or bone defects in the future.

The Efficiency of Highly Porous β-Tricalcium Phosphate With Bone Marrow Aspirate Concentrate in Midfoot Joint Arthrodesis

BACKGROUND

Nonunion is one of the most common and devastating complications following midfoot joint arthrodesis. Many different types of bone grafts and bone substitutes have been used to promote osseous fusion. However, there is no consensus on the gold standard bone grafting material and whether biologic materials should be used alone or in combination. The purpose of this study is to investigate the efficiency of highly porous β-tricalcium phosphate (β-TCP) with bone marrow aspirate concentrate (BMAC) in midfoot joint arthrodesis.

METHODS

This retrospective comparative study included patients who underwent midfoot joint arthrodesis using compression screws. Patients were classified into 2 groups: arthrodesis with highly porous β-TCP and BMAC (group A) and arthrodesis without them (group B). The osseous union rate was compared between the 2 groups. A total of 44 patients (46 feet) including 89 joints were included in this study.

RESULTS

There was a significant difference in the union rate between the 2 groups: 91.5% (43/47 joints) in arthrodesis with highly porous β-TCP and BMAC (group A) and 76.2% (32/42 joints) in arthrodesis without highly porous β-TCP and BMAC (group B; P = .048).

CONCLUSION

This study investigated the efficiency of highly porous β-TCP and BMAC to promote bony healing in midfoot joint arthrodesis. A significantly higher union rate was shown when arthrodesis was performed with highly porous β-TCP and BMAC, compared with arthrodesis performed without them. We suggest that highly porous β-TCP and BMAC can be a viable and effective adjunct to the fixation in midfoot joint arthrodesis.

LEVEL OF EVIDENCE

Level III: Retrospective comparative analysis.

Mesenchymal Stem/Stromal Cells: Immunomodulatory and Bone Regeneration Potential after Tumor Excision in Osteosarcoma Patients

Osteosarcoma (OS) is a type of bone cancer that is derived from primitive mesenchymal cells typically affecting children and young adults. The current standard of treatment is a combination of neoadjuvant chemotherapy and surgical resection of the cancerous bone. Post-resection challenges in bone regeneration arise. To determine the appropriate amount of bone to be removed, preoperative imaging techniques such as bone and CT scans are employed. To prevent local recurrence, the current standard of care suggests maintaining bony and soft tissue margins from 3 to 7 cm beyond the tumor. The amount of bone removed in an OS patient leaves too large of a deficit for bone to form on its own and requires reconstruction with metal implants or allografts. Both methods require the bone to heal, either to the implant or across the allograft junction, often in the setting of marrow-killing chemotherapy. Therefore, the issue of bone regeneration within the surgically resected margins remains an important challenge for the patient, family, and treating providers. Mesenchymal stem/stromal cells (MSCs) are potential agents for enhancing bone regeneration post tumor resection. MSCs, used with scaffolds and growth factors, show promise in fostering bone regeneration in OS cases. We spotlight two MSC types-bone marrow-derived (BM-MSCs) and adipose tissue-derived (ASCs)-highlighting their bone regrowth facilitation and immunomodulatory effects on immune cells like macrophages and T cells, enhancing therapeutic outcomes. The objective of this review is two-fold: review work demonstrating any ability of MSCs to target the deranged immune system in the OS microenvironment, and synthesize the available literature on the use of MSCs as a therapeutic option for stimulating bone regrowth in OS patients post bone resection. When it comes to repairing bone defects, both MB-MSCs and ASCs hold great potential for stimulating bone regeneration. Research has showcased their effectiveness in reconstructing bone defects while maintaining a non-tumorigenic role following wide resection of bone tumors, underscoring their capability to enhance bone healing and regeneration following tumor excisions.

The use of a new grafting material (b.Bone™) for the management of severely depressed tibial plateau fractures: Preliminary report of three cases

Tibial plateau fractures are often complex injuries that result from high-energy trauma affecting the articular congruity of the knee. Managing tibial plateau fractures can be challenging because of severe depression of the subchondral cancellous bone and concomitant cartilage injury. Bone substitutes are commonly used to fill such defects as part of the surgical treatment of tibial plateau fractures. We describe three cases of tibial plateau fractures managed with a synthetic bone substitute (b.Bone™, GreenBone ORTHO S.p.A Faenza, Italy) with a highly interconnected and porous 3D structure to mimic the hierarchical architecture and morphology of natural human bone.

Current concepts of bone grafting in trauma surgery

Bone graft in trauma surgery is commonly used in managing bone defects, non-union, fracture related infections, arthrodesis or to provide structural support in fractures. A variety of bone grafts are made available to the treating physician, which includes autograft, allograft and bone graft substitutes. The future of bone grafting in trauma surgery is exciting with the incorporation of technological advancement such as gene therapy, 3D-printing and tissue engineering. Regardless, there are still limitations to what we understand regarding current bone grafting techniques with conflicting literature on their clinical utility and indication. The aim of this review article therefore is to take a step back and critically evaluate the current concepts of bone grafting in trauma surgery, with special emphasis made on reviewing the types of bone graft, biology of bone graft incorporation and indication for its use in various clinical scenarios.

Orthobiologics: a review

PURPOSE

The use of biologic materials in orthopaedics (orthobiologics) has gained significant attention over the past years. To enhance the body of the related literature, this review article is aimed at summarizing these novel biologic therapies in orthopaedics and at discussing their multiple clinical implementations and outcomes.

METHODS

This review of the literature presents the methods, clinical applications, impact, cost-effectiveness, and outcomes, as well as the current indications and future perspectives of orthobiologics, namely, platelet-rich plasma, mesenchymal stem cells, bone marrow aspirate concentrate, growth factors, and tissue engineering.

RESULTS

Currently available studies have used variable methods of research including biologic materials as well as patient populations and outcome measurements, therefore making comparison of studies difficult. Key features for the study and use of orthobiologics include minimal invasiveness, great healing potential, and reasonable cost as a nonoperative treatment option. Their clinical applications have been described for common orthopaedic pathologies such as osteoarthritis, articular cartilage defects, bone defects and fracture nonunions, ligament injuries, and tendinopathies.

CONCLUSIONS

Orthobiologics-based therapies have shown noticeable clinical results at the short- and mid-term. It is crucial that these therapies remain effective and stable in the long term. The optimal design for a successful scaffold remains to be further determined.

Human periodontal ligament stem cells with distinct osteogenic potential induce bone formation in rat calvaria defects

Aim: This study aimed to evaluate the ability of human periodontal ligament stem cells (PDLSCs) with high (HP-PDLSCs) and low (LP-PDLSCs) osteogenic potential, in addition to mixed cells, to repair bone tissue. Methods: Cell phenotype, proliferation and differentiation were evaluated. Undifferentiated PDLSCs were injected into rat calvarial defects and the new bone was evaluated by μCT, histology and real-time PCR. Results: PDLSCs exhibited a typical mesenchymal stem cell phenotype and HP-PDLSCs showed lower proliferative and higher osteogenic potential than LP-PDLSCs. PDLSCs induced similar bone formation and histological analysis suggests a remodeling process, confirmed by osteogenic and osteoclastogenic markers, especially in tissues derived from defects treated with HP-PDLSCs. Conclusion: PDLSCs induced similar bone formation irrespective of their in vitro osteogenic potential.

One-stage combined "fix and flap" approach for complex open Gustilo-Anderson IIIB lower limbs fractures: a prospective review of 102 cases

BACKGROUND

Management of open fractures is challenging and requires a multidisciplinary team approach. This study aims to evaluate outcomes of open Gustilo-Anderson IIIB fractures managed at a single Ortho-Plastic centre following One-stage "Fix and Flap" approach.

METHODS

Prospective data review for patients presenting with Gustilo-Anderson IIIB Fractures to our centre and managed with one-stage "Fix and Flap" approach. Postoperative outcomes are presented only for the patients who had a minimum of 12 months postoperative follow-up.

RESULTS

120 patients were included (83 males and 37 females). Mean age was 43 years (10-96). Tibia diaphysis was the most common site of injury (60%). 55.9% of injuries were road traffic accidents (RTA). 102 out of 120 patients had a minimum of 12 months follow-up (mean follow-up duration 25 months). Meantime from injury until definitive surgery was 7.71 days. Primary union achieved in 86.73%. Delayed union was encountered in 10.20%. 3.06% of patients had non-union. Limb salvage rate was 97.05% and Deep infection rate was only 0.98%.

CONCLUSION

Our results showed that low infection rate, high limb salvage rate, and high union rate can be achieved in these complex injuries with meticulous technique, combined Ortho-Plastic (Fix and Flap) approach, and MDT input.

Efficacy of Arthroscopic Shavers for the Retrieval and Processing of Connective Tissue Progenitor Cells from Subacromial Bursal Tissue

The purpose of this study is to determine if arthroscopic shavers can effectively collect and process connective tissue progenitor (CTP) cells from subacromial bursal tissue for utilization in rotator cuff repair augmentation. Subacromial bursal tissue was collected and processed using two arthroscopic shavers, Shaver A and Shaver B, in 10 patients undergoing arthroscopic rotator cuff repair. Each shaver was used in a random order for the same patient. Tissue samples underwent testing for cellular proliferation, cellular concentration, number of colony-forming units (CFU), live/dead assay, fluorescence-activated cells sorting (FACS) analysis, cytokine analysis, and growth factor analysis. Shaver A produced more CFUs compared to Shaver B (210.3 vs. 125.9; p < 0.001). At 3 weeks, cells collected via Shaver A had greater cellular proliferation (0.35 vs. 0.51; p < 0.001) as well as more viable cells (214,773 vs. 132,356 cells/gram; p < 0.001). Tissue collected with Shaver B had greater amounts of the cytokines MMP-1 (3741 vs. 5500 pg/mL; p < 0.001), MMP-3 (1131 vs. 1871 pg/mL; p < 0.001), and MMP-13 (179 vs. 401 pg/mL; p < 0.001), while those collected with Shaver A had greater vascular endothelial growth factor (VEGF) (47.8 vs. 9.0 pg/mL; p < 0.05). Arthroscopic shavers are capable of harvesting and processing CTP cells from subacromial bursal tissue. Different shavers may produce different yields of viable CTP cells.

Reconstruction of massive tibial defect caused by osteomyelitis using induced membrane followed by trifocal bone transport technique: a retrospective study and our experience

OBJECTIVE

To evaluate clinical outcomes of the application of induced membrane followed by trifocal bone transport technique in the treatment of massive tibial defect caused by osteomyelitis.

METHOD

A total of 18 eligible patients with tibial defect > 6 cm caused by osteomyelitis who were admitted to our institution from January 2010 to January 2016 and treated by induced membrane followed by trifocal bone transport technique. There were 12 male and 6 females with an average age of 40.4 years old. A detailed demographic data (age, sex, etiology, previous operation time, defect size and location, interval from Masquelet technique to trifocal bone transport technique, external fixation index (EFI), duration of regenerate consolidation and docking union) were collected, bone and functional outcomes were evaluated by Association for the Study and Application of the Method of Ilizarov (ASAMI) scoring system. Complications during and in the period of follow up were recorded and evaluated by Paley classification at a minimum follow-up of 2 years.

RESULTS

The etiology include posttraumatic osteomyelitis in 13 cases and primary osteomyelitis in 5 cases. An average of previous operation time was 3.4 times. Mean tibial defect after radical debridement was 6.8 cm. An average interval duration from formation of induced membrane to trifocal bone transport was 4.8 weeks. An average of EFI was 37.1 days/cm, the duration of regenerate consolidation and docking union were 124.7 days and 186.4 days, respectively. An average time of follow-up after removal of external fixator was 28.5 month without recurrence of osteomyelitis. The bony outcome was excellent in 6 cases, good in 8 cases, fair in 3 cases and poor in 1 case, and functional outcome was excellent in 4 cases, good in 10 cases, fair in 2 cases and poor in 2 cases. The most common complication was pin tract infection which occurred in 15 cases and there were no major complications such as nerve or vascular injury.

CONCLUSION

Massive tibial defect caused by osteomyelitis can be successfully treated first stage using induced membrane followed by second stage using trifocal bone transport technique, which is an effective method in terms of radical elimination of osteomyelitis with expected clinical outcomes.

Significant Improvement in Shoulder Function and Pain in Patients Following Biologic Augmentation of Revision Arthroscopic Rotator Cuff Repair Using an Autologous Fibrin Scaffold and Bone Marrow Aspirate Derived From the Proximal Humerus

Purpose

To clinically evaluate patients who underwent a biologic augmentation technique in revision arthroscopic rotator cuff repair using an autologous fibrin scaffold and concentrated stem cells isolated from bone marrow aspirate (BMA) obtained from the proximal humerus.

Methods

This is a retrospective review of prospectively collected data from patients who underwent biologic augmentation of revision arthroscopic rotator cuff repair using an autologous fibrin scaffold and BMA obtained from the proximal humerus between 2014 and 2015. Minimum follow-up was 12 months. Outcome measures were collected preoperatively and postoperatively including range of motion as well as American Shoulder and Elbow Surgeons Shoulder Form, Simple Shoulder Test, single assessment numeric evaluation, and visual analog score. In addition, BMA samples of each patient were assessed for the number of nucleated cells and colony-forming units. Regression analysis was performed to investigate whether the number of nucleated cells and colony-forming units had an influence on outcome and failure.

Results

Ten patients who underwent biologic augmentation of revision arthroscopic rotator cuff repair using an autologous fibrin scaffold and concentrated BMA obtained from the proximal humerus between 2014 and 2015 were included. The mean follow-up time was 30.7 (range: 12-49) months. Four patients were revised at final follow-up. Postoperative clinical scores improved significantly: American Shoulder and Elbow Surgeons (28.1 ± 5.4 to 60.9 ± 9.0; P < .01), single assessment numeric evaluation (6.6 ± 2.3 to 65.1 ± 10.9; P < .01), visual analog scale (7.2 ± 0.9 to 3.1 ± 0.9; P < .01), and Simple Shoulder Test (1.6 ± 0.5 to 10.3 ± 5.7; P < .01). Postoperative range of motion increased significantly with regard to flexion (97.0 ± 13.6 to 151.0 ± 12.2; P < .01) and abduction (88.0 ± 14.0 to 134.0 ± 15.1; P = .038) but not with external rotation (38.0 ± 5.7 to 50.5 ± 6.5; P = .16). Less pain was correlated to an increased number of nucleated cells (P = .026); however, there was no correlation between failure rate and number of nucleated cells (P = .430).

Conclusions

Patients who underwent biologic augmentation of revision arthroscopic rotator cuff repair using an autologous fibrin scaffold and concentrated BMA demonstrated a significant improvement in shoulder function along with reduction of pain. However, the overall revision rate for this procedure was 40%.

Level of Evidence

Level IV, therapeutic case series.

A single step, centrifuge-free method to harvest bone marrow highly concentrated in mesenchymal stem cells: results of a pilot trial

PURPOSE

The aims of the present study were: (1) to characterize the bone-marrow aspirate (BMA) obtained with a centrifuge-free process, employing a dedicated aspiration device; (2) to test the in vitro efficacy of BMA in a model of cartilage inflammation; and (3) to report the preliminary clinical results in a small cohort of patients affected by knee OA.

METHODS

Ten patients (4 M, 6 W; mean age: 51.9 ± 9.2 yy) affected by mild to moderate unicompartmental knee OA (KL grade 2-3) were treated by intra-articular and subchondral injections of BMA obtained by a centrifuge-free process. To evaluate the effectiveness of the device in harvesting mesenchymal stem cells (MSCs), samples of the obtained BMA were tested by flow cytometry before and after subculture; BMA ability to counteract inflammation was also tested in an in vitro model of cartilage cell inflammation, evaluating the expression of MMP1, MMP3, TGFβ and TIMP-1 by real-time PCR. Patients were also evaluated up to two years' follow-up by using: VAS for pain, IKDC-subjective and KOOS scores.

RESULTS

The laboratory analysis showed that BMSCs accounted for 0.011% of BMA cells, similar to what had been expected in native bone marrow. The paracrine activity of BMA was able to reduce in vitro the catabolic response of human chondrocyte, as shown by the decrease in metalloproteases concentration and increase in anti-inflammatory mediators. Moreover, the clinical evaluation showed significant improvements in all scores adopted, with stable results up to two years.

CONCLUSION

The present data showed the effectiveness of the study device to harvest pure bone marrow with minimal peripheral blood contamination. The relevant content of MSCs resulted in the ability to counteract the catabolic cascade through a paracrine action. The clinical outcomes in patients affected by unicompartmental knee OA were encouraging in terms of pain reduction and functional improvement up to mid-term evaluation.

Panax notoginseng Saponin Promotes Bone Regeneration in Distraction Osteogenesis via the TGF-β1 Signaling Pathway

Distraction osteogenesis (DO) is an efficient strategy that is employed for the treatment of large bone defects in craniomaxillofacial surgery. Despite its utility, however, DO is associated with a prolonged consolidation phase and a high complication rate that hinder its more widespread utilization. Panax notoginseng saponin (PNS) is a traditional Chinese medicine that is frequently administered for the treatment of a range of conditions. Herein, we explored the ability of PNS treatment to influence osteogenic differentiation using both rabbit bone marrow mesenchymal cells (BMSCs) and a model of mandibular DO. BMSC proliferation was assessed via CCK-8 assay, while osteogenic differentiation was monitored through ALP and alizarin red S staining. A PCR approach was used to evaluate the expression of genes associated with osteogenesis (ALP, Runx2, and OCN) and genes linked to the TGF pathway (TβR-II, SMAD2, SMAD3, and PPM1A). For in vivo experiments, treated BMSCs were locally injected into the DO gap, with PNS being injected into treated rabbits every other day throughout the experimental period. The quality of the regenerative process was assessed via scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray imaging, and hematoxylin and eosin (H&E) staining. These analyses revealed that PNS was able to promote BMSC osteogenesis and mandibular generation, driving the upregulation of osteogenesis-related genes at the mRNA levels through the modulation of the TGF-β1/Smad pathway. Consistently, the overexpression or silencing of TβR-II in PNS-treated BMSCs was sufficient to modulate their osteogenic potential. Analyses of in vivo mandibular DO outcomes revealed significantly augmented new bone growth in the PNS-treated group relative to control animals, with maximal osteogenesis in the group overexpressing rabbit TβR-II. Together, these results highlight the PNS as a promising and cost-effective therapeutic tool with the potential to enhance bone regeneration in clinical contexts through the modulation of the TGF-β1/Smad pathway.

Injection of Bone Marrow Aspirate for Glenohumeral Joint Osteoarthritis: A Pilot Randomized Control Trial

Purpose

To compare the efficacy of a single, intra-articular, nonconcentrated bone marrow aspirate (BMA) injection in comparison to cortisone for the treatment of glenohumeral joint osteoarthritis (GHJ OA).

Methods

Inclusion criteria were patients between the ages of 18 and 75 with a diagnosis of GHJ OA on radiograph. Patients were randomized to receive an ultrasound-guided, intra-articular cortisone injection or BMA injection (without concentration). The primary outcome measure was the Western Ontario Osteoarthritis of the Shoulder (WOOS) index at 12 months. Secondary outcome measures were the QuickDASH, EuroQOL 5-dimensions 5-level questionnaire (EQ-5D-5L) and visual analogue scale.

Results

The study included 25 shoulders of 22 patients who completed baseline and 12 months’ patient-reported outcome measures (12 shoulders received cortisone, 13 shoulders received BMA) after the study was terminated early by changes in Health Canada regulations. Baseline characteristics demonstrated a significant difference in the ages of the 2 groups, with the BMA group being older (61.6 vs 53.8 mean years, P = 0.021). For the BMA group, a significant improvement was seen in the WOOS index (P = 0.002), the QuickDASH (P < 0.001), and the EQ-5D-5L pain dimension (P = 0.004) between baseline and 12 months. No significant difference was seen for any outcome in the cortisone group between baseline and 12 months. No significant difference was demonstrated between changes in the WOOS scores from baseline to 12 months when compared between groups (P = 0.07). However, a significant difference in changes in scores was seen in the QuickDASH (P = 0.006) and the EQ-5D-5L pain scores (P = 0.003) and the EQ-5D-5L health scores (P = 0.032) in favor of BMA.

Conclusions

The results of this study demonstrate that patients with GHJ OA treated with BMA have superior changes in the QuickDASH and EQ-5D-5L pain and health scores but not in the WOOS outcomes measures at 12 months post injection when compared to patients treated with cortisone. However, because of the limited number of patients as a result of the early termination of the study, larger randomized studies are required to confirm these findings.

Level of Evidence

Level II, randomized controlled trial.

Autologous Bone Marrow Mononuclear Cells (BMMCs) for the Treatment of Uncomplicated Grade 2 Ununited Anconeal Process (UAP) in Six Dogs: Preliminary Results

The aim of this study was to report the results of autologous bone marrow mononuclear cell (BMMC) transplantation as a minimally invasive treatment for grade 2 UAP in dogs. This was an observational case series on six German shepherd dogs affected by grade 2 UAP as defined according to their clinical condition as well as radiographic and CT findings. Bone marrow was collected from the iliac crest and the mononuclear fraction was separated with density gradient centrifugation. Cells were suspended in fibrin glue before BMMC administration and implanted via transcutaneous injection under IB or CT guidance, using a spinal needle directly inserted into the ossification centre between the anconeal process and the olecranon. Clinical and radiographic follow-up was performed for up to 6 months. Microradiographic assessment was performed on one dog that died of other causes. A progressive reduction of pain within 3 weeks after BMMC administration was observed in all dogs, with gradually increased weight bearing on the affected limb. Radiographic and CT follow-up revealed the progressive fusion of the ossification centre at 90 days without any signs of secondary OA. The examination of microradiographs showed newly formed bone tissue in which a residue of calcified cartilage was present at the site of BMMC implantation. On the basis of these results, BMMC therapy for grade 2 UAP may be considered to be an effective and minimally invasive treatment option for dogs.

Arthroscopic Fixation of Knee Femoral Condyle Osteochondritis Dissecans Fragment With Bone Marrow Aspirate Concentrate

This article reviews a technique for arthroscopic fixation of an osteochondritis dissecans fragment with bone marrow aspirate concentrate augmentation. This technique involves safe harvest of bone marrow arthroscopically from the intercondylar notch, proper preparation and debridement of the parent bone, reduction of the progeny osteochondritis dissecans fragment, insertion of the bone marrow aspirate concentrate, and placement of multiple headless compression screws for fixation.

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.

Nucleated Cell Count Has Negligible Predictive Value for the Number of Colony-Forming Units for Connective Tissue Progenitor Cells (Stem Cells) in Bone Marrow Aspirate Harvested From the Proximal Humerus During Arthroscopic Rotator Cuff Repair

PURPOSE

To evaluate whether nucleated cell count (NCC) could serve as an approximation for the number of colony-forming units (CFUs) in concentrated bone marrow aspirate (cBMA) obtained from the proximal humerus.

METHODS

Bone marrow aspirate (BMA) was harvested from the proximal humerus in 96 patients (mean age 56.2 ± 7.0 years) during arthroscopic rotator cuff repair. Following concentration of the aspirate, nucleated cells of each sample were counted. The total number of CFUs was evaluated under the microscope at their first appearance, usually after 5 to 10 days in culture. Fluorescence-activated cell sorting analysis and assays for osteogenic, adipogenic, and chondrogenic differentiation were performed. Linear regression was assessed to predict the number of CFUs by using NCC. Age, sex, and body mass index (BMI) were evaluated as independent variables.

RESULTS

The average volume of the obtained BMA was 86.7 ± 35.2 mL. The cBMA contained a mean of 26.3 ± 6.8 × 10⁶ nucleated cells per mL, which yielded a mean of 1421.7 ± 802.7 CFUs in cell culture. There were no significant differences in NCC or number of CFUs when sex, volume of BMA, age, or BMI was examined independently (P >.05, respectively). Linear regression found that NCC was of limited predictive value for the total number of CFUs being yielded after cell culture (r² = 0.28 with a root mean square error of 679.4).

CONCLUSION

NCC was of negligible predictive value for the total number of CFUs for connective tissue progenitor cells in BMA harvested from the proximal humerus during arthroscopic rotator cuff repair.

CLINICAL RELEVANCE

NCC is often used to assess the quality of cBMA samples for biological augmentation during surgery. The limited predictive value of this measurement tool is of clinical importance, because effectiveness of BMA applications has been suggested to depend on the concentration of progenitor cells within the sample.

Bone Marrow Aspirate Concentrate as a Reliable Adjunct in Tibiotalocalcanal Fusion: A Radiographic Modified RUST Score Analysis

BACKGROUND

Tibiotalar and subtalar arthritis requiring tibiotalocalcaneal (TTC) fusion can be technically challenging and is dependent on reliable fusion for a good clinical outcome. Initial data regarding bone marrow aspirate concentrate (BMAC) has shown promise in use as an aide in both fracture and fusion healing. The purpose of this study is to determine the outcomes in TTC fusion when utilizing BMAC as an adjunct.

METHODS

Twenty consecutive patients who underwent TTC fusion with BMAC adjunct between March 2013 and November 2017 were retrospectively screened for inclusion. Patients were included regardless of comorbidities or risk factors for non-union, and only excluded if they did not have a minimum of 12 months of clinical and/or radiographic chart data. Follow-up was obtained at regular intervals of 6 weeks, 3 months, 6 months and 1 year. Modified RUST scores were applied to grade bony union in a blinded fashion by two orthopedic trauma fellowship-trained surgeons and agreement was assessed via intraclass correlation coefficient (ICC).

RESULTS

Twenty patients were screened and 12 met inclusion criteria for analysis. Majority were male (66.6%) at a mean age of 55.4 years and they were all treated via TTC fusion for a diagnosis of tibiotalar and subtalar arthritis. There were no postoperative complications and no reoperations in this cohort; no donor site morbidity was associated with BMAC. By the 3-month follow-up timepoint, all but one patient received a minimum modified RUST score of 10 indicating bony union (ICC 0.91); by the 6-month time point (ICC 0.94), all 12 patients were deemed united.

CONCLUSION

BMAC as an adjunct in the setting of TTC fusion is a safe treatment option that can promote reliable, consistent bony fusion with minimal complications.

Treatment of infected tibial non-unions using a BMAC and S53P4 BAG combination for reconstruction of segmental bone defects: A clinical case series

INTRODUCTION

Treatment of infected non-unions of the tibia is a challenging problem. The cornerstones of optimal infected non-union treatment consist of extensive debridement, fracture fixation, antimicrobial therapy and creation of an optimal local biological bone healing environment. The combination of S53P4 bioactive glass (BAG), as osteostimulative antibacterial bone graft substitute, and bone marrow aspirate concentrate (BMAC) for the implantation of mesenchymal stem cells and growth factors might be a promising combination. In this paper, preliminary results of a new treatment algorithm for infected non-unions of the tibia is presented.

METHODS

In this retrospective case series patients with infected non-unions of the tibia are treated according to a new treatment algorithm. Patients are treated with extensive debridement surgery, replacement of the osteosynthesis and implantation of S53P4 BAG and BMAC in a one-stage or two-stage procedure based on non-union severity. Subsequently patients are treated with culture based antibiotic therapy and followed until union and infection eradication.

RESULTS

Five patients with an infected non-union were treated, mean age was 55, average NUSS-score was 44 and the average segmental bone defect was 4.6cm. One patient was treated in a one-stage procedure and four patients in a two-stage induced membrane-, or "Masquelet"-procedure. On average, 23 ml S53P4 BAG and 6.2 ml BMAC was implanted. The mean follow-up period was 13.6 months and at the end of follow-up all patients had clinical consolidation with an average RUST-score of 7.8 and complete eradication of infection.

DISCUSSION

These early data on the combined implantation of S53P4 BAG and BMAC in treatment of infected non-unions shows promising results. These fracture healing results and eradication rates resulted in promising functional recovery of the patients. To substantiate these results, larger and higher quality studies should be performed.

A historical review and bibliometric analysis of research on fracture nonunion in the last three decades

BACKGROUND

Nonunion continues to be the most frequent and challenging complication to treat following fracture fixation. Herein, we carried out a bibliometric analysis aiming to identify the key researchers, centres and research trends developed during the past 30 years in this important clinical condition.

METHODS

The Science Citation Index Expanded database and the Web of Science Core Collection were interrogated for manuscripts published between 1990 and 2019 in the topic domain, utilising title, abstract, author keywords and KeyWords Plus. Overall, such citation indicators were used as TC_year, C_year and CPP_year to help analyse the identified manuscripts.

RESULTS

Over the prespecified period, there was a steady increase in the number of articles published in fracture nonunion. In total, 12 languages were the primary languages in the documents, with English being the most prevalent. The CPP sharply increased to reach a plateau in three full years and up to a peak in ten full years. A total of 8976 nonunion-related articles in Science Citation Index Expanded (SCI-EXPANDED) were published in 790 journals. The 8976 articles were published by 26,079 authors among 101 different countries. There is a slightly fluctuating steady increase of articles from 116 in 1991 to 201 in 2003, and thereafter, the number of articles sharply increased to reach a plateau in 2015. Seven possible main research foci in nonunion-related research were identified including: epidemiology, classification, aetiology, diagnosis/prediction, treatment modalities, functional outcomes and health economics.

CONCLUSIONS

This bibliometric analysis revealed information on citation number, publication outputs, categories, journals, institutions, countries, research highlights and tendencies. The current research activity on fracture nonunion identified key opinion leaders and leading research institutions focusing on this important clinical condition. It is hoped that the informed included will aid to guide research work in the foreseeable future.

Bone healing: Advances in biology and technology

Fracture healing is a complex cascade of cellular and molecular processes. These processes require the appropriate cellular and molecular environment to ensure the restoration of skeletal stability and resolution of inflammation. In order for fracture healing to occur, the necessary building blocks for bone metabolism and synthesis must be supplied through proper nutrition. Pharmacologic therapies aimed at modulating the inflammatory response to fractures have the potential to interfere with the synthesis of molecules needed for the production of bone. Infection can interfere with, and even prevent normal fracture healing from occurring. Cellular and genetic treatment strategies are actively being developed to target deficiencies, and bridge gaps that can influence how fractures heal. Evolving technologies, including nutritional supplementation, pharmacotherapies, antibiotics, surgical techniques, as well as genetic and cellular therapies, have the potential to enhance, optimize, and even revolutionize the process of fracture healing.

The Role of Bone Marrow Aspirate in Osseous and Soft Tissue Pathology

Bone marrow aspirate (BMA) is an emerging therapy that is gaining popularity for orthoplastic reconstruction. The stem cells collected are multipotent and regenerative in nature. In addition to stem cells, other biological components collected augment the mitogen of local cells, proliferation, and angiogenesis, and inhibit proinflammatory cytokine and bacteria to optimize an environment to heal. The most common site for harvest is the iliac crest. Techniques for harvesting BMA are simple to perform, financially modest, and associated with low morbidity. Additional research is needed to evolve and standardize the technology; however, BMA is proven to be advantageous for tissue repair.

Clinical Application of Bone Marrow Mesenchymal Stem/Stromal Cells to Repair Skeletal Tissue

There has been an escalation in reports over the last decade examining the efficacy of bone marrow derived mesenchymal stem/stromal cells (BMSC) in bone tissue engineering and regenerative medicine-based applications. The multipotent differentiation potential, myelosupportive capacity, anti-inflammatory and immune-modulatory properties of BMSC underpins their versatile nature as therapeutic agents. This review addresses the current limitations and challenges of exogenous autologous and allogeneic BMSC based regenerative skeletal therapies in combination with bioactive molecules, cellular derivatives, genetic manipulation, biocompatible hydrogels, solid and composite scaffolds. The review highlights the current approaches and recent developments in utilizing endogenous BMSC activation or exogenous BMSC for the repair of long bone and vertebrae fractures due to osteoporosis or trauma. Current advances employing BMSC based therapies for bone regeneration of craniofacial defects is also discussed. Moreover, this review discusses the latest developments utilizing BMSC therapies in the preclinical and clinical settings, including the treatment of bone related diseases such as Osteogenesis Imperfecta.

Qualifying Osteogenic Potency Assay Metrics for Human Multipotent Stromal Cells: TGF-β2 a Telling Eligible Biomarker

Potency assays are critical for regenerative medicine, addressing the known challenge of functional heterogeneity among human multipotent stromal cells (hMSC). Necessary laboratory cell expansion allows analysis before implantation in the patient. Levels of induction of five signature gene biomarkers, ALPL, COL1A2, DCN, ELN and RUNX2, constituted a previously reported proof-of-principle osteogenic potency assay. We tested assay modification to enhance reproducibility using six consistent bone marrow derived hBM-MSC and explored applicability to three adipose tissue derived hAT-MSC. Using a potent proprietary osteogenic induction factor, the GUSB/YWAHZ reference gene pair provided real time PCR consistency. The novel assay conditions supported the concept that genes encoding extracellular matrix proteins one week after osteogenic induction were informative. Nonetheless, relatively low induction of COL1A2 and ELN encouraged search for additional biomarkers. TGFB2 mRNA induction, important for osteogenic commitment, was readily quantifiable in both hBM-MSC and hAT-MSC. Combined with DCN, TGFB2 mRNA induction data provided discriminatory power for resolving donor-specific heterogeneity. Histomorphometric decorin and TGF-β2 protein expression patterns in eight-week heterotopic bone implants also discriminated the two non-bone-forming hMSC. We highlight progress towards prompt osteogenic potency assays, needed by current clinical trials to accelerate improved intervention with enhanced stem cell therapy for serious bone fractures.

Treatment options for aseptic tibial diaphyseal nonunion: A review of selected studies

In aseptic tibial diaphyseal nonunions after failed conservative treatment, the recommended treatment is a reamed intramedullary (IM) nail.Typically, when an aseptic tibial nonunion previously treated with an IM nail is found, it is advisable to change the previous IM nail for a larger diameter reamed and locked IM nail (the rate of success of renailing is around 90%).A second change after an IM nail failure is also a good option, especially if bone healing has progressed after the first change.Fibular osteotomy is not routinely advised; it is only recommended when it interferes with the nonunion site.In delayed unions before 24 weeks, IM nail dynamization can be performed as a less invasive option before deciding on a nail change.If there is a bone defect, a bone graft must be recommended, with the gold standard being the autologous iliac crest bone graft (AICBG).A reamer-irrigator-aspirator (RIA) system might also obtain a bone autograft that is comparable to AICBG.Although the size of the bone defect suitable to perform bone transport techniques is a controversial issue, we believe that such techniques can be considered in bone defects > 3 cm.Non-invasive therapies and biologic therapies could be applied in isolation for patients with high surgical risk, or could be used as adjuvants to the aforementioned surgical treatments. Cite this article: EFORT Open Rev 2020;5:835-844. DOI: 10.1302/2058-5241.5.190077.

Subacromial Bursa-Derived Cells Demonstrate High Proliferation Potential Regardless of Patient Demographics and Rotator Cuff Tear Characteristics

PURPOSE

To investigate the influence of patient demographics and rotator cuff tear characteristics on the cellular proliferation potential of subacromial bursa-derived cells (SBDCs).

METHODS

Patients undergoing arthroscopic rotator cuff repair between December 2017 and February 2019 were considered for enrollment in the study. Basic demographic information as well as medical and surgical history were obtained for each patient. Subacromial bursa was harvested from over the rotator cuff tendon. Cellular proliferation was evaluated after 3 weeks of incubation by counting nucleated SBDCs. Fluorescence-activated cell sorting (FACS) analysis was performed to confirm the presence of mesenchymal stem cell (MSC) specific surface markers. Using preoperative radiographs and magnetic resonance imaging (MRI), acromiohumeral distance (AHD), severity of cuff tear arthropathy, and rotator cuff tear characteristics were evaluated.

RESULTS

Seventy-three patients (mean age: 57.2 ± 8.5 years) were included in the study. There was no significant difference in cellular proliferation of SBDCs when evaluating the influence of age, sex, body mass index (BMI), smoking status, and presence of systemic comorbidities (p > .05, respectively). Similarly, there was no significant difference in cellular proliferation of SBDCs when looking at rotator cuff tear characteristics (size, tendon retraction, fatty infiltration, muscle atrophy), AHD, or severity of cuff tear arthropathy (p > .05). FACS analysis confirmed nucleated SBDCs to have a high positive rate of MSC specific surface markers.

CONCLUSION

Subacromial bursa consistently demonstrated a high cellular proliferation potential regardless of patient demographics, rotator cuff tear characteristics, and severity of glenohumeral joint degeneration.

CLINICAL RELEVANCE

These findings may alleviate concerns that subacromial bursa might lose cellular proliferation potential when being used for biologic augmentation in massive and degenerated rotator cuff tears, thus assisting in predicting tendon healing and facilitating surgical decision-making.

Systematic review assessing the evidence for the use of stem cells in fracture healing

AIMS

Bone demonstrates good healing capacity, with a variety of strategies being utilized to enhance this healing. One potential strategy that has been suggested is the use of stem cells to accelerate healing.

METHODS

The following databases were searched: MEDLINE, CENTRAL, EMBASE, Cochrane Database of Systematic Reviews, WHO-ICTRP, ClinicalTrials.gov, as well as reference checking of included studies. The inclusion criteria for the study were: population (any adults who have sustained a fracture, not including those with pre-existing bone defects); intervention (use of stem cells from any source in the fracture site by any mechanism); and control (fracture healing without the use of stem cells). Studies without a comparator were also included. The outcome was any reported outcomes. The study design was randomized controlled trials, non-randomized or observational studies, and case series.

RESULTS

In all, 94 eligible studies were identified. The clinical and methodological aspects of the studies were too heterogeneous for a meta-analysis to be undertaken. A narrative synthesis examined study characteristics, stem cell methods (source, aspiration, concentration, and application) and outcomes.

CONCLUSION

Insufficient high-quality evidence is available to determine the efficacy of stem cells for fracture healing. The studies were heterogeneous in population, methods, and outcomes. Work to address these issues and establish standards for future research should be undertaken.Cite this article: Bone Joint Open 2020;1-10:628-638.

Jones Fracture Management in Athletes

Jones fractures in both elite and recreational athletes are best treated with surgical fixation, given superior results as compared to nonoperative management. While screw specifics remain controversial, intramedullary screw fixation is established as the standard surgical technique. Plate fixation also has shown excellent outcomes. Complications of refracture, nonunion, and delayed union require careful evaluation for contributions of early return to play, implant characteristics, and anatomic/metabolic abnormality. Revision fixation with autograft and biologic augmentation is supported in the literature, with ongoing inquiry to optimizing specific implants and adjuvants.

Role of the Ilizarov non-free bone plasty in the management of long bone defects and nonunion: Problems solved and unsolved

BACKGROUND

Ilizarov non-free bone plasty is a method of distraction osteogenesis using the Ilizarov apparatus for external fixation which originated in Russia and was disseminated across the world. It has been used in long bone defect and nonunion management along with free vascularized grafting and induced membrane technique. However, the shortcomings and problems of these methods still remain the issues which restrict their overall use.

AIM

To study the recent available literature on the role of Ilizarov non-free bone plasty in long bone defect and nonunion management, its problems and the solutions to these problems in order to achieve better treatment outcomes.

METHODS

Three databases (PubMed, Scopus, and Web of Science) were searched for literature sources on distraction osteogenesis, free vascularized grafting and induced membrane technique used in long bone defect and nonunion treatment within a five-year period (2015-2019). Full-text clinical articles in the English language were selected for analysis only if they contained treatment results, complications and described large patient samples (not less than ten cases for congenital, post-tumor resection cases or rare conditions, and more than 20 cases for the rest). Case reports were excluded.

RESULTS

Fifty full-text articles and reviews on distraction osteogenesis were chosen. Thirty-five clinical studies containing large series of patients treated with this method and problems with its outcome were analyzed. It was found that distraction osteogenesis techniques provide treatment for segmental bone defects and nonunion of the lower extremity in many clinical situations, especially in complex problems. The Ilizarov techniques treat the triad of problems simultaneously (bone loss, soft-tissue loss and infection). Management of tibial defects mostly utilizes the Ilizarov circular fixator. Monolateral fixators are preferable in the femur. The use of a ring fixator is recommended in patients with an infected tibial bone gap of more than 6 cm. High rates of successful treatment were reported by the authors that ranged from 77% to 100% and depended on the pathology and the type of Ilizarov technique used. Hybrid fixation and autogenous grafting are the most applicable solutions to avoid after-frame regenerate fracture or deformity and docking site nonunion.

CONCLUSION

The role of Ilizarov non-free bone plasty has not lost its significance in the treatment of segmental bone defects despite the shortcomings and treatment problems encountered.

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.

Current and future uses of skeletal stem cells for bone regeneration

The postnatal skeleton undergoes growth, modeling, and remodeling. The human skeleton is a composite of diverse tissue types, including bone, cartilage, fat, fibroblasts, nerves, blood vessels, and hematopoietic cells. Fracture nonunion and bone defects are among the most challenging clinical problems in orthopedic trauma. The incidence of nonunion or bone defects following fractures is increasing. Stem and progenitor cells mediate homeostasis and regeneration in postnatal tissue, including bone tissue. As multipotent stem cells, skeletal stem cells (SSCs) have a strong effect on the growth, differentiation, and repair of bone regeneration. In recent years, a number of important studies have characterized the hierarchy, differential potential, and bone formation of SSCs. Here, we describe studies on and applications of SSCs and/or mesenchymal stem cells for bone regeneration.

Bone Marrow Aspirate Concentrate: Its Uses in Osteoarthritis

Human bone marrow (BM) is a kind of source of mesenchymal stem cells (MSCs) as well as growth factors and cytokines that may aid anti-inflammation and regeneration for various tissues, including cartilage and bone. However, since MSCs in BM usually occupy only a small fraction (0.001%) of nucleated cells, bone marrow aspirate concentrate (BMAC) for cartilage pathologies, such as cartilage degeneration, defect, and osteoarthritis, have gained considerable recognition in the last few years due to its potential benefits including disease modifying and regenerative capacity. Although further research with well-designed, randomized, controlled clinical trials is needed to elucidate the exact mechanism of BMAC, this may have the most noteworthy effect in patients with osteoarthritis. The purpose of this article is to review the general characteristics of BMAC, including its constituent, action mechanisms, and related issues. Moreover, this article aims to summarize the clinical outcomes of BMAC reported to date.

Bone marrow-derived products: A classification proposal - bone marrow aspirate, bone marrow aspirate concentrate or hybrid?

Degenerative musculoskeletal disorders are one of the top causes of pain and disability in the adult population. Current available alternatives to mitigate symptoms include conservative treatments such as the administration of pharmacological agents and an educative approach towards lifestyle modification. The use of certain analgesics, such as opiates and corticosteroids, delivers short term results but do not address the etiological source of pain and disability. Also, prolonged use of such medications may cause additional complications. Therefore, the demand for musculoskeletal tissue regeneration has led to an alternative approach referred to as "orthobiologics". This alternative is based on cellular and molecular components capable of inducing and promoting tissue repair. Bone marrow (BM) aspirate (BMA) and concentrate are well-known orthobiologics used to treat musculoskeletal conditions. Orthobiologics derived from the BM have been discussed in the literature; however, the lack of standardization regarding collection and processing protocols presents a challenge for generalization of study outcomes and determination of efficacy. Since BM-derived orthobiologics have not yet been classified, to our knowledge, this manuscript proposes the ACH classification system, which speaks to BMA (A), BMA and concentrate (C) and hybrid (H), which combines A and C. This classification proposes and describes 8 parameters that are relevant for the quality of biological products. The more parameters used would imply greater characterization and complexity of the evaluation of the biological product used. The ACH classification envisages a necessary contribution to the comprehension of both clinical procedures and research outcomes, ultimately ushering in a standardization of best practice.

Intralesional Injection of Bone Marrow Aspirate Concentrate for the Treatment of Osteonecrosis of the Knee Secondary to Systemic Lupus Erythematosus: A Case Report

Case: An 18-year-old female patient with Systemic Lupus Erythematosus (SLE) and corticosteroid-associated extensive bilateral symptomatic knee Osteonecrosis (ON) (Ficat IV), treated with sequential intralesional injections of autologous bone marrow aspirate concentrate (BMAC) under ultrasound guidance. At 3 months, pain was almost absent (VAS) and KOOS/WOMAC showed significant improvement sustained up to 24 months. At 12 months MRI indicated bone maturation, significantly reduced BM edema and subchondral fluid volume, and no collapse/fragmentation signs.

Discussion: The clinical and imaging significant improvement observed in this patient suggests that BMAC intralesional injections effectively restored the compromised bone structure. After larger studies, this technique can become an alternative to decompressing surgery for ON cases.

Transplantation of IL-10-Overexpressing Bone Marrow-Derived Mesenchymal Stem Cells Ameliorates Diabetic-Induced Impaired Fracture Healing in Mice

Background

Diabetes mellitus is characterized by hyperglycemia which displays insufficiency or resistance to insulin. One of the complications of diabetes is the increased risk of fracture and the impairment of bone repair and regulation. There have been evidences from previous studies that mesenchymal stem cells (MSCs) from bone marrow promote cartilage and callous formation. In addition, IL-10, an anti-inflammatory cytokine, has been observed to relieve inflammation-related complications in diabetes.

Methods

In this study, the role of IL-10-overexpressing bone marrow-derived MSCs (BM-MSCs) was examined in the diabetic mice model with femur fracture. MSCs were isolated from the BALB/c mice and IL-10 over expression was conducted with lentivirus transduction. The streptozotocin (STZ)-induced diabetes model with femoral fracture was established. BM-MSCs with IL-10 over expression were transplanted into the fracture area. The expressions of inflammatory factors IL-6, TNF-α and INF-γ were examined by qPCR and immunoblot; the biomechanical strength of the fracture site of the mice was examined and evaluated.

Results

Data showed that IL-10 overexpressed BM-MSCs transplantation decreased inflammatory response, promoted bone formation, and increased the strength of the fracture site in STZ-induced diabetic mice with femoral fracture.

Conclusion

IL-10 overexpressed BM-MSCs transplantation accelerated fracture repair in STZ-induced diabetic mice, which in turn provides potential clinical application prospects.

A Rationale for the Use of Clotted Vertebral Bone Marrow to Aid Tissue Regeneration Following Spinal Surgery

Vertebral body bone marrow aspirate (V-BMA), easily accessible simultaneously with the preparation of the site for pedicle screw insertion during spinal procedures, is becoming an increasingly used cell therapy approach in spinal surgery. However, the main drawbacks for V-BMA use are the lack of a standardized procedure and of a structural texture with the possibility of diffusion away from the implant site. The aim of this study was to evaluate, characterize and compare the biological characteristics of MSCs from clotted V-BMA and MSCs from whole and concentrate V-BMAs. MSCs from clotted V-BMA showed the highest cell viability and growth factors expression (TGF-β, VEGF-A, FGF2), the greatest colony forming unit (CFU) potency, cellular homogeneity, ability to differentiate towards the osteogenic (COL1AI, TNFRSF11B, BGLAP) and chondrogenic phenotype (SOX9) and the lowest ability to differentiate toward the adipogenic lineage (ADIPOQ) in comparison to all the other culture conditions. Additionally, results revealed that MSCs, differently isolated, expressed different level of HOX and TALE signatures and that PBX1 and MEIS3 were down-regulated in MSCs from clotted V-BMA in comparison to concentrated one. The study demonstrated for the first time that the cellular source inside the clotted V-BMA showed the best biological properties, representing an alternative and advanced cell therapy approach for patients undergoing spinal surgery.

Evaluation of the Consistency and Composition of Commercially Available Bone Marrow Aspirate Concentrate Systems

Background:

Bone marrow aspirate (BMA) concentrate (BMAC) has gained popularity as a treatment modality for various orthopaedic conditions; however, there are still inconsistencies in its reported therapeutic efficacy. This may be because of the many different commercial BMAC preparation systems used clinically, which generate dissimilar concentrate products.

Purpose:

To compare 3 commercially available BMAC preparation systems: Harvest SmartPrep 3, Biomet BioCUE, and Arthrex Angel. We evaluated the consistency of each of these systems and compared the composition of their concentrate products.

Study Design:

Controlled laboratory study.

Methods:

A total of 10 patients donated whole blood and BMA, which were combined and processed with the 3 different BMAC preparation systems. Samples were taken before and after processing for the measurement of white blood cells (WBC), platelets (PLT), CD34+ cells, and colony-forming unit–fibroblast (CFU-F). To evaluate consistency, the variances of cell yield and concentration increase from baseline for each cell type were compared between systems. To compare concentrate product composition, differences between the systems’ mean cell yield and concentration increase from baseline for each cell type were evaluated.

Results:

The Harvest system (variance, 0.25) concentrated WBC more consistently than the Arthrex system (variance, 3.25) (P = .024), but no other differences in consistency were noted between the 3 systems. The Harvest system recovered the greatest percentage of CFU-F (82.4% ± 18.2%), CD34+ cells (81.1% ± 28.5%), and WBC (77.3% ± 8.6%), whereas the Biomet system recovered the greatest percentage of PLTs (92.9% ± 27.3%). The Arthrex system concentrated PLT to the greatest degree (11.10 ± 2.05 times baseline), while the Biomet system concentrated WBC to the greatest degree (5.99 ± 1.04 times baseline).

Conclusion:

The consistency of the 3 systems was similar for all but 1 of the evaluated cell types. However, the composition of the concentrate products differed across systems. This may grant each system unique advantages without having to sacrifice reproducibility.

Clinical Relevance:

Understanding the consistency of different BMAC preparation systems and their product makeup may aid in determining optimal therapeutic doses of different cell types.

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.

Comparison of Preparation Techniques for Isolating Subacromial Bursa-Derived Cells as a Potential Augment for Rotator Cuff Repair

PURPOSE

To identify an effective, nonenzymatic method for maximizing the yield of subacromial bursa-derived nucleated cells for augmenting rotator cuff repair.

METHODS

Subacromial bursa (minimum 0.2 g) was collected prospectively over the supraspinatus from patients (n = 7) with at least one full-thickness tendon tear undergoing arthroscopic primary rotator cuff repair. Samples were processed and analyzed prospectively using 4 different methods: (1) mechanical digestion with scissors (chopping), (2) collagenase digestion, (3) mechanical digestion with a tissue homogenizer, and (4) whole tissue with minimal manipulation. Tissue from each method were plated and cultured in a low oxygen tension, humidified incubator for 7 days. Following incubation, cellularity was assessed with nucleated cell count using a Coulter Counter. Flow cytometry was performed on the non-enzymatic method that demonstrated the greatest cell count to confirm the presence of mesenchymal stem cells (MSCs). The Kruskal-Wallis H test and post hoc Dunn's test were used for statistical analysis.

RESULTS

Following incubation, mean nucleated cell counts (cells/mL) were (1) 102,681 ± 73,249 for chopping, (2) 76,190 ± 66,275 for collagenase, (3) 31,686 ± 29,234 for homogenization, and (4) 11,162 ± 4016 for whole tissue. There was no significant difference between chopping and collagenase (P = .45) or between homogenization and collagenase (P = .52). Both chopping (P = .003) and collagenase (P = .03) produced significantly more cells when compared with whole tissue. Flow cytometry confirmed the presence of MSC markers on samples processed by chopping.

CONCLUSIONS

Mechanical isolation of subacromial bursa-derived cells using a chopping technique demonstrated similar nucleated cell count compared with collagenase, along with the confirmed presence of MSCs.

CLINICAL RELEVANCE

This study demonstrated a nonenzymatic, mechanical method for isolating subacromial bursa-derived cells to potentially augment rotator cuff repair. Further clinical studies are required to assess its possible advent in the tendon-bone healing process.

Bone Marrow-Derived Cell Therapies to Heal Long-Bone Nonunions: A Systematic Review and Meta-Analysis-Which Is the Best Available Treatment?

Nonunions represent one of the major indications for clinical settings with stem cell-based therapies. The objective of this research was to systematically assess the current evidence for the efficacy of bone marrow-derived cell-based approaches associated or not with bone scaffolds for the treatment of nonunions. We searched MEDLINE (PubMed) and CENTRAL up to July 2019 for clinical studies focused on the use of cell-based therapies and bone marrow derivatives to treat bone nonunions. Three investigators independently extracted the data and appraised the risk of bias. We analysed 27 studies including a total number of 347 participants exposed to four interventions: bone marrow concentrate (BMAC), BMAC combined with scaffold (BMAC/Scaffold), bone marrow-derived mesenchymal stromal cells (BMSCs), and BMSC combined with scaffold (BMSC/Scaffold). Two controlled studies showed a positive trend in bone healing in favour of BMAC/Scaffold or BMSC/Scaffold treatment against bone autograft, although the difference was not statistically significant (RR 0.11, 95% CI -0.05; 0.28). Among single cohort studies, the highest mean pooled proportion of healing rate was reported for BMAC (77%; 95% CI 63%-89%; 107 cases, n = 8) and BMAC/Scaffold treatments with (71%; 95% CI 50%-89%; 117 cases, n = 8) at 6 months of follow-up. At 12 months of follow-up, an increasing proportion of bone healing was observed in all the treatment groups, ranging from 81% to 100%. These results indicate that BMAC or BMAC/Scaffold might be considered as the primary choice to treat nonunions with a successful healing rate at a midterm follow-up. Moreover, this meta-analysis highlighted that the presence of a scaffold positively influences the healing rate at a long-term follow-up. More case-control studies are still needed to support the clinical improvement of cell-based therapies against autografts, up to now considered as the gold standard for the treatment of nonunions.

The effect of a single consecutive volume aspiration on concentrated bone marrow from the proximal humerus for clinical application

BACKGROUND

Low aspiration volumes have been recommended to allow for higher concentrations of progenitor cells during bone marrow harvesting. However, these guidelines then require multiple aspiration attempts in order to maximize cellular yield. The purpose of this study was to investigate the effect of a single, high-volume aspiration with four consecutive aliquots on the number of nucleated cells (NCs) and colony-forming units (CFUs) in concentrated bone marrow aspirate (cBMA) taken from the proximal humerus.

METHODS

cBMA was taken from the proximal humerus of patients undergoing arthroscopic rotator cuff surgery. Four 12-mL double syringes were used consecutively from a single trocar to obtain four 10 cc aliquots. Each then underwent centrifugation to create a fractionated layer rich in nucleated cells. Following cellular separation, NCs were counted and CFUs were evaluated after incubation of 7-10 days. Cellular comparisons between each aliquot were performed along with their interaction with patient age and sex.

RESULTS

Twenty-nine patients (55.9 ± 4.6 years) were included in this study. The number of NCs and CFUs showed significant differences between the four aliquots of aspirate, with the first 10 cc aliquot providing the highest amount (p < 0.001, respectively). No significant differences were found between the sum of the three sequential aliquots compared to the initial 10 cc sample. There were no significant differences between male and female patients (p > 0.05). Increasing age resulted in no significant decrease in the number of NCs and CFUs across the four consecutive aliquots (p > 0.05).

CONCLUSION

In conclusion, while the initial aliquot provided the greatest number of nucleated cells and cultured CFUs, the addition of each sequential volume aspirate yielded similar amounts in total. This demonstrates the potential effectiveness of obtaining of higher volume aspirates from the proximal humerus during rotator cuff repair.

Examining the Potency of Subacromial Bursal Cells as a Potential Augmentation for Rotator Cuff Healing: An In Vitro Study

PURPOSE

To compare the potency of mesenchymal stem cells between the cells derived from the subacromial bursa to concentrated bone marrow aspirate (cBMA) taken from patients undergoing rotator cuff (RC) repair.

METHODS

Subacromial bursa and cBMA were harvested arthroscopically from 13 patients (age 57.4 ± 5.2 years, mean ± standard deviation) undergoing arthroscopic primary RC repair. Bone marrow was aspirated from the proximal humerus and concentrated using an automated system (Angel System; Arthrex). Subacromial bursa was collected from 2 sites (over the RC tendon and muscle) and digested with collagenase to isolate a single cellular fraction. Proliferation, number of colony-forming units, differentiation potential, and gene expression were compared among the cells derived from each specimen.

RESULTS

The cells derived from subacromial bursa showed significantly higher proliferation compared with the cells derived from cBMA after 5, 7, and 10 days (P = .018). Regarding colony-forming units, the subacromial bursa had significantly more colonies than cBMA (P = .002). Subacromial bursal cells over the RC tendon produced significantly more colonies than cells over both the RC muscle and cBMA (P = .033 and P = .028, respectively). Moreover, when compared with cBMA, cells derived from subacromial bursa showed significantly higher differentiation ability and higher gene expression indicative of chondrogenesis, osteogenesis, and adipogenesis.

CONCLUSION

The subacromial bursa is an easily accessible tissue that can be obtained during RC repair, with significant pluripotent stem cell potency for tendon healing. Compared with cBMA taken from the proximal humerus, bursal cells showed significantly increased differentiation ability and gene expression over time.

CLINICAL RELEVANCE

Failed RC repairs have been partly attributed to a poor healing environment. Biologic augmentation of the repair site may help increase healing potential and incorporation of the cuff at the tendon-bone interface.

Ex vivo gene therapy using human bone marrow cells overexpressing BMP-2: "Next-day" gene therapy versus standard "two-step" approach

Traditionally, ex vivo gene therapy involves a two-step approach, with culture expansion of cells prior to transduction and implantation. We have tried to simplify this strategy and eliminate the time and cost associated with culture expansion, by introducing "next-day" regional gene therapy using human bone marrow cells. The purpose of this study was to determine whether a lentiviral vector (LV) carrying the cDNA for BMP-2 can transduce freshly isolated human BM cells, leading to abundant BMP production and bone formation in vivo, and evaluate the in vivo osteoinductive potential of "next-day" gene therapy and the standard "two-step" tissue culture expansion approach. To this end, human bone marrow cells (HBMC) from patients undergoing total hip arthroplasty were harvested, transduced with a BMP-2-expressing LV either overnight ("next day" gene therapy; ND) or after culture expansion (cultured "two-step" approach; C) and then implanted into a rat critical-sized femoral defect. The animals were randomly assigned to one of the following groups: I; ND-HBMC transduced with LV-TSTA BMP-2, II; ND-HBMC transduced with LV-TSTA GFP, III; non-transduced ND-HBMC; IV; C-HBMC transduced with LV-TSTA BMP-2, V; C-HBMC transduced with LV-TSTA-GFP, VI; non-transduced C-HBMC. Treatment with either "next-day" or cultured HBMC demonstrated a significant increase in new bone formation compared with all negative control groups as seen in plain radiographs, microCT and histologic/histomorphometric analysis. At 12 weeks post-op, complete defect union on plain X-rays occurred in 7/14 animals in the ND-HBMC/BMP-2 group and 12/14 in the C-HBMC/BMP-2 treated rats. The two-step approach was associated with more consistent results, a higher union rate, and superiority with regards to all of the studied bone healing parameters. In this study we demonstrate proof of concept that BMP-2-transduced human bone marrow cells can be used to enhance bone healing in segmental bone defects, and that regional gene therapy using lentiviral transduction has the osteoinductive potential to heal large bone defects in clinical settings.

The combination of Decitabine and EPZ-6438 effectively facilitate adipogenic differentiation of induced pluripotent stem cell-derived mesenchymal stem cells

As a novel type of mesenchymal stem cell, induced pluripotent stem cell-derived mesenchymal stem cells (iPMSCs) have huge potential for cell therapy. iPMSCs exhibited the typical characteristics of MSCs, whereas the tri-lineage differentiation potential is limited, especially the adipogenic propensity. Here, to reveal the molecular mechanism we carried out the epigenetic comparisons between the iPMSCs and the bone marrow-derived mesenchymal stem cells (BMSCs) and embryonic stem cell-derived mesenchymal stem cells (EMSCs). We found that the iPMSCs was significantly higher than the BMSCs in terms of genome-wide DNA methylation. Meanwhile, the adipogenic gene PPARγ promoter region existed hypermethylation. In addition, compared with EMSCs and BMSCs, iPMSCs had significant differences in the histones epigenetic modification of methylation and acetylation, especially high levels of histone 27 lysine trimethylation (H3K27me3). Furthermore, the epigenetic modifiers Decitabine and EPZ6438 effectively upregulated the gene expression of PPARγ and promoted the adipogenic differentiation of iPMSCs via chromatin remodeling. Taken together, our findings set new metrics to the applications for improving the efficiency and the therapeutic potential of iPMSCs.