Bone marrow aspirate concentrate and platelet-rich plasma enhanced bone healing in distraction osteogenesis of the tibia

Cellular therapies for bone repair: current insights

Mesenchymal stem cells are core to bone homeostasis and repair. They both provide the progenitor cells from which bone cells are formed and regulate the local cytokine environment to create a pro-osteogenic environment. Dysregulation of these cells is often seen in orthopaedic pathology and can be manipulated by the physician treating the patient. This narrative review aims to describe the common applications of cell therapies to bone healing whilst also suggesting the future direction of these techniques.

Biomaterials for bone defect repair: Types, mechanisms and effects

Bone defects or bone discontinuities caused by trauma, infection, tumours and other diseases have led to an increasing demand for bone grafts and biomaterials. Autologous bone grafts, bone grafts with vascular tips, anastomosed vascular bone grafts and autologous bone marrow components are all commonly used in clinical practice, while oversized bone defects require the use of bone tissue engineering-related biomaterials to repair bone defects and promote bone regeneration. Currently, inorganic components such as polysaccharides and bioceramics, as well as a variety of bioactive proteins, metal ions and stem cells can be loaded into hydrogels or 3D printed scaffold materials to achieve better therapeutic results. In this review, we provide an overview of the types of materials, applications, potential mechanisms and current developments in the repair of bone defects.

Advances with Platelet-Rich Plasma for Bone Healing

Despite significant advances in the understanding and delivery of osteosynthesis, fracture non-union remains a challenging clinical problem in orthopaedic surgery. To bridge the gap, basic science characterization of fracture healing provides a platform to identify and target biological strategies to enhance fracture healing. Of immense interest, Platelet-rich plasma (PRP) is a point of care orthobiologic that has been extensively studied in bone and soft tissue healing given its relative ease of translation from the benchtop to the clinic. The aim of this narrative review is to describe and relate pre-clinical in-vitro and in-vivo findings to clinical observations investigating the efficacy of PRP to enhance bone healing for primary fracture management and non-union treatment. A particular emphasis is placed on the heterogeneity of PRP preparation techniques, composition, activation strategies, and delivery. In the context of existing data, the routine use of PRP to enhance primary fracture healing and non-union management cannot be supported. However, it is acknowledged that extensive heterogeneity of PRP treatments in clinical studies adds obscurity; ultimately, refinement (and consensus) of PRP treatments for specific clinical indications, including repetition studies are warranted.

Alveolar cleft reconstruction using bone marrow aspirate concentrate and iliac cancellous bone: A 12-month randomized clinical study

OBJECTIVE

This study aimed to compare the bone density and volume in patients with alveolar cleft reconstructions utilizing bone marrow aspirate concentrate with iliac graft versus iliac graft alone.

MATERIAL AND METHODS

Thirty-six patients with unilateral alveolar cleft were randomly allocated into either an intervention group receiving an iliac bone graft mixed with bone marrow concentrate or a control group receiving an iliac bone graft. Cone beam CT was obtained preoperative, 6 and 12 months postoperatively to assess the bone density of the graft and bone volume of the alveolar defect, and then, the bone loss ratio was calculated.

RESULTS

Bone volume and bone density demonstrated a statistically significant increase in the intervention group at 6 and 12 months. In contrast, the bone loss ratio decreased significantly in the intervention group throughout the follow-up period.

CONCLUSION

A combination of bone marrow concentrate and iliac cancellous bone in alveolar cleft reconstruction may improve bone densities and volume in addition to decreasing graft loss rate.

CLINICAL SIGNIFICANCE

Using of bone marrow aspirate concentrate will decrease the amount of the graft needed and decrease the ratio of bone loss at the grafted site by the time. Trial registration ClinicalTrials.org ( NCT04414423 ) 4/6/2020.

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.

Tibial Bone Transport With a Single Implant All-Internal Bone Transport Nail

SUMMARY

A single implant all-internal magnet-driven bone transport nail (BTN-NuVasive Specialized Orthopaedics Inc) has recently been introduced as a treatment method for segmental tibial bone defects. This innovation provides promise in the management of segmental bone defects because it negates numerous complications associated with circular external fixation and the need for multiple implants when considering hybrid plate-assisted bone segment transport constructs. Given the novelty of the BTN, description of the surgical application and patient outcome measures are scarce in the current literature. To date, we have treated 4 patients with an average age of 27 years (range 19-44 years) using the BTN for segmental tibial defects ranging from 50 to 128 mm. We have accumulated data over an average follow-up of 18.07 months (range 12.96-25.13 months), demonstrating good patient tolerance of the device. Three patients successfully completed their treatment course with a calculated average bone healing index of 41.4 days/cm (range 31.41-54.82 days/cm). One patient was noted to experience an asymptomatic docking site nonunion requiring subsequent surgery for nonunion repair. Implant-associated complications included symptomatic implant, axial malalignment, docking site nonunion, and external remote control technical malfunction. Injury-related complications were encountered and noted to include: superficial infection, wound dehiscence, peroneal tendonitis, and joint rigidity. In this study, the authors present a case series using this implant to date and discuss our experiences with the BTN with reference to clinical indications, tibial bone preparation, BTN implantation, transport protocol, docking site procedure, and clinical/radiographic outcomes.

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.

The efficacy of platelet-rich plasma in osseous foot and ankle pathology: a review

The purpose of this review is to develop evidence-based practices for the use of platelet-rich plasma (PRP) to treat osseous pathologies of the lower extremity. There is moderate high-quality evidence to support the efficacy of PRP as a surgical augment to microfracture in osteochondral lesions of the talus (OLT). The literature supports a conceivable positive impact on bony union and osseous healing. There is insufficient evidence to support PRP injections in the conservative management of OLT or symptomatic ankle osteoarthritis. PRP may serve as a viable treatment method in the surgical augmentation of microfracture surgery in OLT and has promise for increasing bony union following surgical operations. Further high-quality, comparative studies with longer clinical follow-up are required.

STRYDE versus PRECICE magnetic internal lengthening nail for femur lengthening

INTRODUCTION

Magnetic internal lengthening nails (MILNs) have been used for femoral lengthening to avoid complications associated with external fixation. The titanium version of the MILN (PRECICE®) has been in use since 2011 but had limitations (50-75 lb) in post-operative weight bearing. A new stainless-steel version of the MILN (STRYDE®) allows 150-250 lb of post-operative weight bearing. The aim is to compare the outcomes of using these two different MILNs for both unilateral and bilateral femoral lengthening.

METHODS

A single-center, retrospective cohort study was conducted in which patients' records were reviewed from the period from January 2017 to March 2020. A total of 66 femoral lengthening procedures were included in the study and were divided into two groups: STRYDE® group (30 femora) and PRECICE® group (36 femora). Outcomes assessed were the 6-months post-operative Limb Deformity-Scoliosis Research Society (LD-SRS) Score, adjacent joint range of motion (ROM), average distraction rate, bone healing index (BHI), and complications.

RESULTS

No statistically significant difference was found between the two groups in regard to the (LD-SRS) score, hip ROM, or knee ROM. Statistically significant differences were found between the two groups in regard to BHI (average of 0.84 months/cm and 0.67 months/cm for STRYDE® and PRECICE®, respectively) and distraction rate (average of 0.6 mm/day and 0.9 mm/day for STRYDE® and PRECICE®, respectively). No mechanical nail complications were reported in the STRYDE® group compared to three events of nail failure in the PRECICE® group. One femur in the PRECICE® group needed BMAC injection for delayed healing compared to four femurs in the STRYDE® group.

CONCLUSION

The STRYDE® MILN yields comparable functional results to those of PRECICE® MILN and shows fewer mechanical nail complications. However, STRYDE® MILN requires a slower distraction rate and yields slower healing (larger BHI).

LEVEL OF EVIDENCE

Level III, Therapeutic study.

Minimally Manipulated Bone Marrow-Derived Cells Can Be Used for Tissue Engineering In Situ and Simultaneous Formation of Personalized Tissue Models

Red bone marrow and autologous bone tissue (bone fragments and bone chips) of the donor were harvested intraoperatively during autoplasty of talus bone defect. Titanium chips were obtained by grinding a fragment of a microporous titanium-coated hip arthroplasty (Zimmer). Bone marrow mononuclear cells were isolated in the operating room, and bone and titanium fragments were incubated with a suspension of mononuclear cells. The quality of revitalization was assessed by fluorescence microscopy and histological examination after culturing of adherent cells on the bone and titanium fragments. During culturing on bone chips, bone marrow mononuclear fraction cells demonstrated significantly higher metabolic activity than bone marrow cells (p=0.04). Mononuclear fraction cells were also capable of stable colonization of titanium fragments with the formation of composite tissue model.

The role of Platelet Rich Plasma and other orthobiologics in bone healing and fracture management: A systematic review

BACKGROUND

Treatment of large bone defects and fracture healing complications (delayed and non-union) presents a substantial challenge for orthopaedic surgeons. Given that bone healing requires mechanical stability as well as a favourable biological microenvironment, orthobiologics such as Platelet-Rich Plasma (PRP) may have a significant clinical role to play.

AIMS

To perform a systematic review of the available literature to assess the clinical effect of PRP, with or without other orthobiologics, on bone healing.

METHOD

Two independent reviewers performed the literature search based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Clinical studies of any evidence, assessing effect of PRP with or without other orthobiologics on bone healing, were included. A qualitative analysis was carried out on the clinical and radiological outcomes reported.

RESULT

27 articles with 1631 patients (mean age = 43.56, 57.1% male, mean follow-up = 17.27 months) were included in the qualitative. Of the 27 studies, 13 dealt with fracture complications (delayed or non-unions), 7 with acute fracture healing, 4 with tibial osteotomies and lengthening procedures and 3 with lumbar spine pathology. 18/27 studies showed a clinical benefit of PRP, 8/27 showed no significant effect, and 1/27 showed a worse outcome with PRP.

CONCLUSION

Our review suggests PRP may play a clinical role in bone healing but further randomised controlled trials (RCTs) using standardised outcomes should be performed to establish its efficacy.

Cell Therapy: Types, Regulation, and Clinical Benefits

Cell therapy practices date back to the 19th century and continue to expand on investigational and investment grounds. Cell therapy includes stem cell- and non-stem cell-based, unicellular and multicellular therapies, with different immunophenotypic profiles, isolation techniques, mechanisms of action, and regulatory levels. Following the steps of their predecessor cell therapies that have become established or commercialized, investigational and premarket approval-exempt cell therapies continue to provide patients with promising therapeutic benefits in different disease areas. In this review article, we delineate the vast types of cell therapy, including stem cell-based and non-stem cell-based cell therapies, and create the first-in-literature compilation of the different "multicellular" therapies used in clinical settings. Besides providing the nuts and bolts of FDA policies regulating their use, we discuss the benefits of cell therapies reported in 3 therapeutic areas-regenerative medicine, immune diseases, and cancer. Finally, we contemplate the recent attention shift toward combined therapy approaches, highlighting the factors that render multicellular therapies a more attractive option than their unicellular counterparts.

Orthobiologics in the treatment of hip disorders

Orthobiologics are biological materials that are intended for the regeneration or healing of bone, cartilage and soft tissues. In this review we discuss the use of orthobiologics for hip disorders providing an update. The orthobiologics included in this article are hyaluronic acid, platelet rich plasma, bone marrow, adipose tissue and expanded mesenchymal stem cells. We explain the concepts and definitions of each orthobiological product, and the literature regarding its use in the hip joint. The paucity of guidelines for the production and characterization of the biological products leads to uneven results across the literature. Each biologic therapy has indications and benefits; however, noteworthy are the characterization of the orthobiologics, the application method and outcome analysis for further improvement of each technique.

Platelet-rich plasma vs bone marrow aspirate concentrate: An overview of mechanisms of action and orthobiologic synergistic effects

The use of orthobiologics as a novel therapy for the treatment of numerous musculoskeletal disorders has increased considerably over the past decade. Currently, there are multiple alternatives available as suitable treatments; however, the use of autologous blood-derived products such as platelet-rich plasma (PRP), bone marrow aspirate (BMA) and BMA concentrate (BMAC), specifically, is expanding. Although many investigations attempted to demonstrate the effectiveness of these therapies, even with positive results, the literature lacks standardized protocols and overall accuracy in study designs, which leads to variance and difficulty in reproducibility of protocols. The efficacy of PRP for the treatment of cartilage, bone and muscle tissues is well known. Although BMAC has generated optimistic results for the same purposes, its applicability in clinical trials is still relatively recent when compared to PRP. Both products demonstrate the potential to set forth reparative processes, each in their own distinct mechanism. The combination of these biological products has been previously proposed, yet little is known about their synergism. Evidence indicates that growth factor, cytokine, and chemokine profiles seen in both PRP and BMAC vary but are likely to work synergistically to enhance musculoskeletal healing. BMAC products seem to work well without PRP; however, the addition of PRP to BMAC has been shown to act as a rich and natural source of culture medium for stem cells located either peripherally or in the bone marrow itself. Nevertheless, additional variables associated with the use of BMAC and PRP in orthopedics must be further evaluated in order to consolidate the efficacy of this therapeutic strategy.

Management of Osseous Defects in the Tibia: Utilization of External Fixation, Distraction Osteogenesis, and Bone Transport

The use of external fixators for distraction osteogenesis has revolutionized treatment options for segmental bone defects in the tibia. Following corticotomy, the latency phase allows the biologic environment to initiate healing, and optimized distraction rates produce regenerate. Regenerate consolidation can be improved with local and systemic biologic optimization. Consolidation time is often considered to be 3 to 4 times longer than distraction in adults. Soft tissue considerations are important during external fixation and distraction. Additionally, slow regenerate can be benefited by various techniques discussed in this article. Distraction osteogenesis is a beneficial tool for segmental bone defects.

Combined administration of platelet rich plasma and autologous bone marrow aspirate concentrate for spinal cord injury: a descriptive case series

Administration of platelet rich plasma (PRP) and bone marrow aspirate concentrate (BMAC) has shown some promise in the treatment of neurological conditions; however, there is limited information on combined administration. As such, the purpose of this study was to assess safety and functional outcomes for patients administered combined autologous PRP and BMAC for spinal cord injury (SCI). This retrospective case series included seven patients who received combined treatment of autologous PRP and BMAC via intravenous and intrathecal administration as salvage therapy for SCI. Patients were reviewed for adverse reactions and clinical outcomes using the Oswestry Disability Index (ODI) for up to 1 year, as permitted by availability of follow-up data. Injury levels ranged from C3 through T11, and elapsed time between injury and salvage therapy ranged from 2.4 months to 6.2 years. Post-procedure complications were mild and rare, consisting only of self-limited headache and subjective memory impairment in one patient. Four patients experienced severe disability prior to PRP combined with BMAC injection, as evidenced by high (> 48/100) Oswestry Disability Index scores. Longitudinal Oswestry Disability Index scores for two patients with incomplete SCI at C6 and C7, both of whom had cervical spine injuries, demonstrated a decrease of 28–40% following salvage therapy, representing an improvement from severe to minimal disability. In conclusion, intrathecal/intravenous co-administration of PRP and BMAC resulted in no significant complications and may have had some clinical benefits. Larger clinical studies are needed to further test this method of treatment for patients with SCI who otherwise have limited meaningful treatment options. This study was reviewed and approved by the OhioHealth Institutional Review Board (IRB No. 1204946) on May 16, 2018.

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.

Comparison of concentrated fresh mononuclear cells and cultured mesenchymal stem cells from bone marrow for bone regeneration

Autologous bone marrow mononuclear cell (BMMNC) transplantation has been widely studied in recent years. The fresh cell cocktail in BMMNCs, without going through the in vitro culture process, helps to establish a stable microenvironment for osteogenesis, and each cell type may play a unique role in bone regeneration. Our study compared the efficacy of concentrated fresh BMMNCs and cultured bone marrow‐derived mesenchymal stem cells (BMSCs) in Beagle dogs for the first time. Fifteen‐millimeter segmental bone defects were created in the animals' tibia bones. In BMMNCs group, the defects were repaired with concentrated fresh BMMNCs combined with β‐TCP (n = 5); in cultured BMSC group, with in vitro cultured and osteo‐induced BMSCs combined with β‐TCP (n = 5); in scaffold‐only group, with a β‐TCP graft alone (n = 5); and in blank group, nothing was grafted (n = 3). The healing process was monitored by X‐rays and single photon emission computed tomography. The animals were sacrificed 12 months after surgery and their tibias were harvested and analyzed by microcomputed tomography and hard tissue histology. Moreover, the microstructure, chemical components, and microbiomechanical properties of the regenerated bone tissue were explored by multiphoton microscopy, Raman spectroscopy and nanoindentation. The results showed that BMMNCs group promoted much more bone regeneration than cultured BMSC group. The grafts in BMMNCs group were better mineralized, and they had collagen arrangement and microbiomechanical properties similar to the contralateral native tibia bone. These results indicate that concentrated fresh bone marrow mononuclear cells may be superior to in vitro expanded stem cells in segmental bone defect repair.

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.

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.

Relevant advances in bone lengthening research: a bibliometric analysis of the 100 most-cited articles published from 2001 to 2017

This study aimed to assess the scientific production of bone lengthening research by identifying the most-cited papers. All articles including the term 'bone lengthening' published between 2001 and 2017 were retrieved through the Web of Science database. The 100 most-cited articles on bone lengthening included a total of 4244 citations, with 414 (9.7%) citations in 2017. There was an average of 249.6 citations per year. The articles predominantly addressed biomechanics and bone formation (38). Different surgical techniques, including intramedullary nail (14), Ilizarov (nine), intramedullary skeletal kinetic distractor (ISKD) (six), Taylor spatial frame (6), the PRECICE device (three), and lengthening and submuscular locking plate (three), were the second most-studied topic. Most studies were therapeutic (58), whereas 30 studies were experimental investigations using animal models. Among the clinical studies, case series were predominant (level of evidence IV) (57). This study presents the first bibliometric analysis of the most relevant articles on bone lengthening. The list is relatively comprehensive in terms of identifying the top issues in this field. However, the most influential clinical studies have a poor level of evidence, although a slight tendency toward a better level of evidence has been observed in more recent years.

Bone marrow concentrate-induced mesenchymal stem cell conditioned medium facilitates wound healing and prevents hypertrophic scar formation in a rabbit ear model

Background

Hypertrophic scars (HSs) are formed via an aberrant response to the wound healing process. HSs can be cosmetic or can result in functional problems. Prolonged proliferation and remodeling phases disrupt wound healing, leading to excessive collagen production and HS formation. However, there are currently no satisfactory drugs to prevent HS formation. Mesenchymal stem cell (MSC) conditioned medium (CM) has therapeutic effects on wound healing and preventing HS formation. Bone marrow concentrate (BMC) contains various growth factors and cytokines that are crucial for regeneration and has been applied in the clinical setting. In this study, we evaluated the effects of BMC-induced MSC CM on HS formation in a rabbit ear model.

Methods

We established a rabbit ear wound model by generating full-thickness wounds in the ears of rabbits (n = 12) and treated wounds with MSC CM, BMC CM, or BMC-induced MSC CM. Dermal fibroblasts from human hypertrophic scar were stimulated with transforming growth factor beta 1 (TGF-β1) for 24 h and cultured in each culture medium for 72 h. We measured the hypertrophic scar (HS) formation during the skin regeneration by measuring the expression of several remodeling molecules and the effect of these conditioned media on active human HS fibroblasts.

Results

Our results showed that BMC-induced MSC CM had greater antifibrotic effects than MSC CM and BMC CM significantly attenuated HS formation in rabbits. BMC-induced MSC CM accelerated wound re-epithelization by increasing cell proliferation. Additionally, BMC-induced MSC CM also inhibited fibrosis by decreasing profibrotic gene and protein expression, promoting extracellular matrix turnover, inhibiting fibroblast contraction, and reversing myofibroblast activation.

Conclusions

BMC-induced MSC CM modulated the proliferation and remodeling phases of wound healing, representing a potential wound healing agent and approach for preventing HS formation.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1383-x) contains supplementary material, which is available to authorized users.

Mesenchymal stem cells as adjuvant therapy for limb lengthening in achondroplasia

Staged leg lengthening allows achondroplastic dwarfs to reach nearly normal height, but it takes long periods of external fixation and it can be burdened by delayed unions. Between 2009 and 2013, eight achondroplastic dwarfs showed delayed unions in the callus formation during femoral lengthening stages in our institute. We performed in-situ injections of bone marrow-derived stem cell concentrates. Patients underwent monthly clinical and radiographic assessment for determination of the healing rate. All eight patients showed an improvement in the regenerated bone, with an average healing index of 23.1 days/cm (range: 18.7-23.8 days/cm). The complete recovery of the delayed consolidation took on an average of 5.2 months (range: 2-10 months). The use of cellular therapy in these patients could represent an innovative application.

Low-intensity pulsed ultrasound enhances callus consolidation in distraction osteogenesis of the tibia by the technique of lengthening over the nail procedure

BACKGROUND

Low-intensity pulsed ultrasound (LIPUS) has been widely accepted in promoting the fracture healing process. However, there have been limited clinical trials focused on the efficacy of LIPUS during distraction osteogenesis (DO) by the technique of lengthening over the nail procedure. The purpose of the current study was to evaluate the efficacy of LIPUS during DO.

METHODS

We retrospectively evaluated 30 patients (60 segments) who underwent simultaneous bilateral tibial lengthening over the nail. The patients were grouped into the LIPUS group and the control group based on LIPUS stimulation. The two patient groups were compared for demographic data (sex, age at operation, preoperative height, BMI, and smoking history), qualitative assessments of the callus (callus shape and type), external fixation index, and four cortical healing indexes.

RESULTS

Fifteen patients (30 segments) were classified as the LIPUS group, and another 15 patients (30 segments) were classified as the control group. No significant differences were found in the assessed demographic data between the groups. LIPUS stimulated a more cylindrical, more homogenous, and denser type of callus formation at the end of the distraction phase. The two groups exhibited equivalent outcomes in terms of external fixation index (p = 0.579). However, significant differences were found in healing indexes of the anterior and medial cortices (p <  0.001 and p = 0.002, respectively). The healing indexes of those cortices in the LIPUS group (mean of 36.6 days/cm and 32.5 days/cm, respectively) reflected their significantly faster healing compared to the control group (mean HI of 57.5 days/cm and 44.2 days/cm, respectively). There were no LIPUS-related complications.

CONCLUSIONS

LIPUS is a noninvasive and effective adjuvant therapy to enhance callus maturation during DO. It enhances callus consolidation and may have a positive effect on the appropriate callus shape and type.

Bone Marrow Aspirate Concentrate for the Treatment of Avascular Meniscus Tears in a One-Step Procedure-Evaluation of an In Vivo Model

Avascular meniscus tears show poor intrinsic regenerative potential. Thus, lesions within this area predispose the patient to developing knee osteoarthritis. Current research focuses on regenerative approaches using growth factors or mesenchymal stem cells (MSCs) to enhance healing capacity within the avascular meniscus zone. The use of MSCs especially as progenitor cells and a source of growth factors has shown promising results. However, present studies use bone-marrow-derived BMSCs in a two-step procedure, which is limiting the transfer in clinical praxis. So, the aim of this study was to evaluate a one-step procedure using bone marrow aspirate concentrate (BMAC), containing BMSCs, for inducing the regeneration of avascular meniscus lesions. Longitudinal meniscus tears of 4 mm in size of the lateral New Zealand White rabbit meniscus were treated with clotted autologous PRP (platelet-rich plasma) or BMAC and a meniscus suture or a meniscus suture alone. Menisci were harvested at 6 and 12 weeks after initial surgery. Macroscopical and histological evaluation was performed according to an established Meniscus Scoring System. BMAC significantly enhanced regeneration of the meniscus lesions in a time-dependent manner and in comparison to the PRP and control groups, where no healing could be observed. Treatment of avascular meniscus lesions with BMAC and meniscus suturing seems to be a promising approach to promote meniscus regeneration in the avascular zone using a one-step procedure.

Bone marrow aspiration concentrate and platelet-rich plasma in the treatment of knee osteoarthritis: A report of three cases

This paper presents the cases of 3 females with knee osteoarthritis. All 3 received a single bone marrow aspiration concentrate (BMAC) injection followed one month later by a platelet-rich plasma (PRP) injection. Compared with the baseline values, pain and functionality scores improved in all the patients. The aim of presenting these cases is to highlight that the combined use of intra-articular BMAC and PRP treatments may have positive effects on pain, functional status and quality of life in patients with knee osteoarthritis.

Regenerative medicine in lower limb reconstruction

Bone is a highly specialized connective tissue and has a rare quality as one of the few tissues that can repair without a scar to regain pre-injury structure and function. Despite the excellent healing capacity of bone, tumor, infection, trauma and surgery can lead to significant bone loss requiring skeletal augmentation. Bone loss in the lower limb poses a complex clinical problem, requiring reconstructive techniques to restore form and function. In the past, amputation may have been the only option; however, there is now an array of reconstructive possibilities and cellular therapies available to salvage a limb. In this review, we will evaluate current applications of bone tissue engineering techniques in limb reconstruction and identify potential strategies for future work.

Autologous cell-based therapy for treatment of large bone defects: from bench to bedside

OBJECTIVES

Reconstruction of long segmental bone defects is demanding for patients and surgeons, and associated with long-term treatment periods and substantial complication rates in addition to high costs. While defects up to 4-5 cm length might be filled up with autologous bone graft, heterologous bone from cadavers, or artificial bone graft substitutes, current options to reconstruct bone defects greater than 5 cm consist of either vascularized free bone transfers, the Masquelet technique or the Ilizarov distraction osteogenesis. Alternatively, autologous cell transplantation is an encouraging treatment option for large bone defects as it eliminates problems such as limited autologous bone availability, allogenic bone immunogenicity, and donor-site morbidity, and might be used for stabilizing loose alloplastic implants.

METHODS

The authors show different cell therapies without expansion in culture, with ex vivo expansion and cell therapy in local bone defects, bone healing and osteonecrosis. Different kinds of cells and scaffolds investigated in our group as well as in vivo transfer studies and BMC used in clinical phase I and IIa clinical trials of our group are shown.

RESULTS

Our research history demonstrated the great potential of various stem cell species to support bone defect healing. It was clearly shown that the combination of different cell types is superior to approaches using single cell types. We further demonstrate that it is feasible to translate preclinically developed protocols from in vitro to in vivo experiments and follow positive convincing results into a clinical setting to use autologous stem cells to support bone healing.

Applications of stem cells in orthodontics and dentofacial orthopedics: Current trends and future perspectives

A simple overview of daily orthodontic practice involves use of brackets, wires and elastomeric modules. However, investigating the underlying effect of orthodontic forces shows various molecular and cellular changes. Also, orthodontics is in close relation with dentofacial orthopedics which involves bone regeneration. In this review current and future applications of stem cells (SCs) in orthodontics and dentofacial orthopedics have been discussed. For craniofacial anomalies, SCs have been applied to regenerate hard tissue (such as treatment of alveolar cleft) and soft tissue (such as treatment of hemifacial macrosomia). Several attempts have been done to reconstruct impaired temporomandibular joint. Also, SCs with or without bone scaffolds and growth factors have been used to regenerate bone following distraction osteogenesis of mandibular bone or maxillary expansion. Current evidence shows that SCs also have potential to be used to regenerate infrabony alveolar defects and move the teeth into regenerated areas. Future application of SCs in orthodontics could involve accelerating tooth movement, regenerating resorbed roots and expanding tooth movement limitations. However, evidence supporting these roles is weak and further studies are required to evaluate the possibility of these ideas.

Reporting Standards in Clinical Studies Evaluating Bone Marrow Aspirate Concentrate: A Systematic Review

PURPOSE

To perform a systematic review of clinical studies evaluating bone marrow aspirate concentrate (BMAC) in the treatment of musculoskeletal pathology to compare levels of reporting with recently published minimum standards.

METHODS

A systematic review of the clinical literature from August 2002 to August 2017 was performed. Human clinical studies published in English and involving the administration of BMAC for musculoskeletal applications were included. Studies evaluating non-concentrated preparations of bone marrow aspirate or preparations of laboratory cultured cells were excluded. Studies evaluating the treatment of dental or maxillofacial conditions were excluded. Similarly, in vitro studies, editorials, letters to the editor, and reviews were excluded. Levels of reporting were compared with previously published minimum standards agreed on through an international Delphi consensus process.

RESULTS

Of 1,580 studies identified on the initial search, 46 satisfied the criteria for inclusion. Considerable deficiencies in reporting of key variables including the details of BMAC preparation and composition were noted. Studies reported information on only 42% (range, 25%-60%) of the variables included within established minimum reporting standards. No study provided adequate information to enable the precise replication of preparation protocols and accurate characterization of the BMAC formulation delivered.

CONCLUSIONS

We found that all existing clinical studies in the literature evaluating BMAC for orthopaedic or sports medicine applications are limited by inadequate reporting of both preparation protocols and composition. Deficient reporting of the variables that may critically influence outcomes precludes interpretation, prevents other researchers from reproducing experimental conditions, and makes comparisons across studies difficult. We encourage the adoption of emerging minimum reporting standards for clinical studies evaluating the use of mesenchymal stem cells in orthopaedics.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I through IV studies.

Facilitated recruitment of mesenchymal stromal cells by bone marrow concentrate and platelet rich plasma

BACKGROUND

Biologics containing growth factors are frequently used to enhance healing after musculoskeletal injuries. One mechanism of action is thought to be though the ability of biologics to induce homing and migration of endogenous mesenchymal stromal cells (MSCs) to a target tissue. However, the ability of biologics to stimulate chemotaxis (directed migration of cells) and chemokinesis (increase rate of cell migration) of MSCs is unknown.

HYPOTHESIS/PURPOSE

The aim of this study was to directly compare the ability of biologics including platelet rich plasma (PRP) and bone marrow concentrate (BMC) to induce MSC migration. The hypothesis was that leukocyte-low platelet rich plasma (Llo PRP) would induce migration to a greater extent than leukocyte-high platelet rich plasma (Lhi PRP) or BMC.

METHODS

Bone marrow-derived MSCs were isolated from 8 horses. Migration of MSCs toward a biologic (BMC, Llo PRP, and Lhi PRP) or the positive control platelet derived growth factor (PDGF) was continuously traced and measured for 24hrs using time-lapse microscopy and a microfluidics device. Cell migration, chemotaxis and chemokinesis were determined by measurements of displacement, number of cells migrated, and cell flux.

RESULTS

All biologics resulted in a significantly greater percentage of MSCs migrated compared to the positive control (PDGF). MSCs migrated further toward BMC compared to Llo PRP. Cell migration, measured as cell flux, was greater toward BMC and Lhi PRP than Llo PRP.

CONCLUSION

The biologics BMC and Lhi PRP elicit greater chemotaxis and chemokinesis of MSCs than Llo PRP. However, all biologics recruited the same number of MSCs suggesting that differences in other regenerative effects, such as growth factor concentration, between biologics should be strongly considered when choosing a biologic for treatment of musculoskeletal injuries. The results of this study have the potential to reduce the need, risks, and costs associated with MSC culture and delivery.

Variability in the Preparation, Reporting, and Use of Bone Marrow Aspirate Concentrate in Musculoskeletal Disorders: A Systematic Review of the Clinical Orthopaedic Literature

BACKGROUND

Interest in the therapeutic potential of bone marrow aspirate concentrate (BMAC) has grown exponentially. However, comparisons among studies and their processing methods are challenging because of inconsistent reporting of protocols, as well as poor characterization of the composition of the initial bone marrow aspirate and of the final products delivered. The purpose of this study was to perform a systematic review of the literature to evaluate the level of reporting related to the protocols used for BMAC preparation and the composition of BMAC utilized in the treatment of musculoskeletal diseases in published clinical studies.

METHODS

A systematic review of the literature was performed by searching PubMed, MEDLINE, the Cochrane Database of Systematic Reviews, and the Cochrane Central Register of Controlled Trials from 1980 to 2016. Inclusion criteria were human clinical trials, English language, and manuscripts that reported on the use of BMAC in musculoskeletal conditions.

RESULTS

After a comprehensive review of the 986 identified articles, 46 articles met the inclusion criteria for analysis. No study provided comprehensive reporting that included a clear description of the preparation protocol that could be used by subsequent investigators to repeat the method. Only 14 (30%) of the studies provided quantitative metrics of the composition of the BMAC final product.

CONCLUSIONS

The reporting of BMAC preparation protocols in clinical studies was highly inconsistent and studies did not provide sufficient information to allow the protocol to be reproduced. Moreover, comparison of the efficacy and yield of BMAC products is precluded by deficiencies in the reporting of preparation methods and composition. Future studies should contain standardized and stepwise descriptions of the BMAC preparation protocol, and the composition of the BMAC delivered, to permit validating and rationally optimizing the role of BMAC in musculoskeletal care.

Comparative Analysis of Cellular and Growth Factor Composition in Bone Marrow Aspirate Concentrate and Platelet-Rich Plasma

The purpose of this study was to quantify the stem cell and growth factor (GF) contents in the bone marrow aspirate concentrate (BMAC) and platelet-rich plasma (PRP) prepared from whole blood using a protocol established in our laboratory. We examined 10 patients with osteonecrosis of the femoral head who were treated by autologous BMAC transplantation at our hospital between January 2015 and June 2015. We quantified CD34+ and CD31−CD45−CD90+CD105+ cells in BMAC and PRP by flow cytometry. Additionally, we measured various GFs, that is, basic fibroblast growth factor (b-FGF), platelet-derived growth factor-BB (PDGF-BB), vascular endothelial growth factor (VEGF), transforming growth factor-β1 (TGF-β1), and bone morphogenetic protein-2 (BMP-2) in BMAC and PRP using enzyme-linked immunosorbent assays and statistical analyses. CD34+ and CD31−45−90+105+ cells accounted for approximately 1.9% and 0.03% of cells in BMAC and no cells in PRP. The concentration of b-FGF was higher in BMAC than in PRP (P < 0.001), whereas no significant differences in the levels of PDGF-BB, VEGF, TGF-β1, and BMP-2 were observed between the two types of sample. BMAC had an average of 1.9% CD34+ and 0.03% CD31−45−90+105+ cells and higher levels of b-FGF than those of PRP.

Bone Marrow Mononuclear Cells Combined with Beta-Tricalcium Phosphate Granules for Alveolar Cleft Repair: A 12-Month Clinical Study

Alveolar cleft is the most common congenital bone defect. Autologous iliac crest bone graft (ICBG) is the most widely adopted procedure for alveolar cleft repair, but the condition is associated with door-site morbidities. For the first time, this study used bone marrow mononuclear cells (BMMNCs) combined with beta-tricalcium phosphate (β-TCP) granules to repair alveolar bone defect. The effectiveness of this technique was compared with autologous ICBG after 12 months of follow-up. The bone formation volume was quantitatively evaluated by three-dimensional computed tomography and computer aided engineering technology. BMMNCs/β-TCP granule grafting was radiographically equivalent to ICBG in alveolar cleft repair. Although considerable resorption was observed up to 6 months after surgery, no significant differences were noted in the Chelsea score and bone formation volume between groups. These finding indicate that BMMNCs/β-TCP grafting is a safe and effective approach for alveolar bone regeneration.

A Call for Standardization in Platelet-Rich Plasma Preparation Protocols and Composition Reporting: A Systematic Review of the Clinical Orthopaedic Literature

BACKGROUND

Platelet-rich plasma (PRP) is a blood-derived preparation whose use has grown exponentially in orthopaedic practice. However, there remains an unclear understanding of the biological properties and effects of PRP on musculoskeletal healing. Heterogeneous processing methods, unstandardized nomenclature, and ambiguous classifications make comparison among studies challenging. A comprehensive assessment of orthopaedic clinical PRP trials is key to unraveling the biological complexity of PRP, while improving standardized communication. Toward this goal, we performed a systematic review of the PRP preparation protocols and PRP composition utilized in clinical trials for the treatment of musculoskeletal diseases.

METHODS

A systematic review of the literature was performed from 2006 to 2016. Inclusion criteria were human clinical trials, English-language literature, and manuscripts that reported on the use of PRP in musculoskeletal/orthopaedic conditions. Basic-science articles, editorials, surveys, special topics, letters to the editor, personal correspondence, and nonorthopaedic applications (including cosmetic use or dental application studies) were excluded.

RESULTS

A total of 105 studies (in 104 articles) met the inclusion criteria for analysis. Of these studies, only 11 (10%) provided comprehensive reporting that included a clear description of the preparation protocol that could be used by subsequent investigators to repeat the method. Only 17 studies (16%) provided quantitative metrics on the composition of the final PRP product.

CONCLUSIONS

Reporting of PRP preparation protocols in clinical studies is highly inconsistent, and the majority of studies did not provide sufficient information to allow the protocol to be reproduced. Furthermore, the current reporting of PRP preparation and composition does not enable comparison of the PRP products being delivered to patients. A detailed, precise, and stepwise description of the PRP preparation protocol is required to allow comparison among studies and provide reproducibility.

A systematic review of the concept and clinical applications of bone marrow aspirate concentrate in tendon pathology

Tendon pathologies are a group of musculoskeletal conditions frequently seen in clinical practice. They can be broadly classified into traumatic, degenerative and overuse-related tendinopathies. Rotator cuff tears, Achilles tendinopathy and tennis elbow are common examples of these conditions. Conventional treatments have shown inconsistent outcomes and might fail to provide satisfactory clinical improvement. With the growing trend towards the use of mesenchymal stem cells (MSCs) in other branches of medicine, there is an increasing interest in treating tendon pathologies using the bone marrow MSC. In this article, we provide a systematic literature review documenting the current status of the use of bone marrow aspirate concentrate (BMAC) for the treatment of tendon pathologies. We also asked the question on the safety of BMAC and whether there are potential complications associated with BMAC therapy. Our hypothesis is that the use of BMAC provides safe clinical benefit when used for the treatment of tendinopathy or as a biological augmentation of tendon repair. We followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) checklist while preparing this systematic review. A literature search was carried out including the online databases of PubMed, EMBASE, ClinicalTrial.gov and the Cochrane Library from 1960 to the end of May 2015. Relevant studies were selected and critically appraised. Data from eligible studies were extracted and classified per type of tendon pathology. We included 37 articles discussing the application and use of BMAC for the treatment of tendon pathologies. The Critical Appraisal Skills Program (CASP) appraisal confirmed a satisfactory standard of 37 studies. Studies were sub-categorised into: techniques of extraction, processing and microscopic examination of BMAC (n = 18), where five studies looked at the evaluation of aspiration techniques (n = 5), augmentation of rotator cuff tears (n = 5), augmentation of tendo-achilles tendon (n = 1), treatment of gluteal tendon injuries (n = 1), management of elbow epicondylitis (n = 2), management of patellar tendinopathy (n = 1) and complications related to BMAC (n = 5). Multiple experimental studies investigated the use of BMAC for tendon repair; nonetheless, there are only limited clinical studies available in this field. Unfortunately, due to the scarcity of studies, which were mainly case series, the current level of evidence is weak. We strongly recommend further future randomised controlled studies in this field to allow scientists and clinicians make evidence-based conclusions.

Outcome of oscillating saw open osteotomy in two-stage lower extremity bone transport with monolateral frame

INTRODUCTION

Bone transport techniques have been widely used to solve massive bone defects due to trauma, osteomyelitis or bone tumors. The technique of bone interruption to achieve better new bone formation is a subject of debate. Low-energy osteotomy (LEO) techniques have been proposed as the gold standard. Some authors reject open osteotomy with an oscillating saw (OOS osteotomy), based on the danger of bone tissue thermal necrosis and periosteal damage. To date, however, there is no strong clinical evidence to discourage this high-energy (HEO) bone interruption technique.

METHODS

The aim of this study was to determine outcomes in using OOS osteotomy in a series of patients, where monolateral-frame bone transport has been used to resolve segmental bone defects of the lower extremity. The minimum accepted follow-up was 1 year. The primary endpoints were radiographic evidence of regenerated bone quality (Li classification) and final outcome (Cattaneo clinical system assessment). Further, we analyzed associated complications, and compared results with other published series. We hypothesized that OOS osteotomy produces results no less favorable than those achieved with other, low-energy techniques.

RESULTS

A total of 54 patients, with an average bone defect of 8.58cm (CI95% 7.01-10.16), were enrolled in the study. In terms of regeneration quality, 84% of the regenerated segment shapes were associated with good outcomes; only 16% exhibited a shape (hypotrophic) predictive of a poor outcome. Regarding functional assessment, following the Cattaneo system, we found a total of 90% good or excellent results. Finally, the Bone Healing Index (BHI) in our series averaged 21.09 days per cm. The main complication observed was pin-track infection, occurring in 45% of the cases.

CONCLUSION

According our data, the superiority of an LEO technique over HEO techniques is yet to be confirmed; it appears that any open osteotomy is effective, performed well and in a proper clinical setting, and that many factors other than choice of osteotomy technique must play important roles.

Optimization of pure platelet-rich plasma preparation: A comparative study of pure platelet-rich plasma obtained using different centrifugal conditions in a single-donor model

While it has been proved that centrifugal conditions for pure platelet-rich plasma (P-PRP) preparation influence the cellular composition of P-PRP obtained, the optimal centrifugal conditions to prepare P-PRP have not yet been identified. In the present study, platelet-containing plasma (PCP) was prepared with the first-spin of different double-spin methods and P-PRP was prepared with different double-spin methods. Whole-blood analysis was performed to evaluate the cellular composition of PCP and P-PRP. The basal and ADP-induced CD62P expression rates of platelets were assessed by flow cytometry to evaluate the function of platelets in PCP and P-PRP. Enzyme-linked immune sorbent assay was performed to quantify interleukin-1β, tumor necrosis factor-α, platelet-derived growth factor AB and transforming growth factor β1 concentrations of PCP and P-PRP. Correlations between the cellular characteristics and cytokine concentrations of P-PRP were analyzed by Pearson correlation analysis. Effects of P-PRP on the proliferation, survival and migration of human bone marrow-derived mesenchymal stem cells and human articular chondrocytes were evaluated by a Cell Counting Kit-8 assay, live/dead staining and Transwell assay, respectively. The results showed that centrifugation at 160 × g for 10 min and 250 × g for 15 min successively captured and concentrated platelets and growth factors significantly more efficiently with preservation of platelet function compared with other conditions (P<0.05). The correlation analysis showed that the similar leukocyte concentrations and leukocyte-reducing efficiencies resulted in similar pro-inflammatory cytokine concentrations in P-PRP (P>0.05) and the maximization of platelet concentration, platelet enrichment factor, platelet capture efficiency and platelet function resulted in the maximization of growth factor concentrations in P-PRP obtained using the optimal conditions (P<0.05). Compared with P-PRP obtained under other conditions, P-PRP obtained under the optimal conditions significantly promoted the proliferation and migration of cells (P<0.05) and did not alter cell survival (P>0.05). Therefore, centrifugation at 160 × g for 10 min and 250 × g for 15 min successively with removal of the buffy coat as a crucial step may provide an optimal preparation system of P-PRP for clinical application.

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

PURPOSE

Fracture healing encompasses a succession of dynamic multifactorial metabolic events, which ultimately re-establishes the integrity of the biomechanical properties of the bone. Up to 10% of the fractures occurring annually will need additional surgical procedures because of impaired healing. The aim of this article is to review the current literature regarding the use of bone marrow aspirate concentrate (BMAC) and its effectiveness in the management of bone defects.

METHODS

We have included all published clinical literature investigating the development, techniques and applications of BMAC. Language, design and risk of bias did not deter the initial inclusion of any study. Our search was exclusively limited to studies involving human subjects. A PRISMA compliant search was carried out as published in 2009. This included the online databases: PubMed, EMBASE, clinical trial.gov and the Cochrane library from 1960 to the end of May 2015. MeSH terms used included: "Bone" AND "Marrow" AND "Aspirate" AND "Concentrate" AND "Bone Defects" AND "NONUNION". Eligible studies were independently appraised by two authors using the Critical Appraisal Skills Program checklist. For the purpose of narrative review, relevant studies were included irrespective of methodology or level of evidence.

RESULTS

Thirty-four of the 103 (48 PubMed and 55 EMBASE) results yielded by the preliminary search were included. Exclusions included three duplicate records, six letters, 17 non-orthopaedics related studies and four records irrelevant to our search topic. The CASP appraisal confirmed a satisfactory standard of 31 studies. They all had clearly defined objectives, were well designed and conducted appropriately to meet them. The published studies reported the use of BMAC in non-union and fracture healing (15 studies), bone defects (nine studies), spine fusion (two studies), distraction osteogensis (two studies) and complications related to the use of BMAC (seven studies).

CONCLUSIONS

Stem cells found in BMAC have the potential to self-renew, undertake clonal expansion and differentiate into different musculoskeletal tissues. The commercial processing of BMAC needs to be optimized in order to achieve a consistent end product, which will provide predicable and translatable results. The future potential of cell characterization in order to determine the optimum cell for repair/regeneration of bone also needs to be explored.

LEVEL OF EVIDENCE

Systematic Review of minimum level IV studies.

A systematic review of the concept and clinical applications of Bone Marrow Aspirate Concentrate in Orthopaedics

Introduction: Mesenchymal stem cells (MSC’s) are believed to have multipotent plasticity with the capability to differentiate along multiple cell lineages such as cartilage, bone, tendon, muscle, and nerve. Such multipotency has the potential to play an important role in the repair and reconstruction of multiple tissues across a number of orthopaedic specialties. Bone marrow and fat are the most abundant and accessible source of MSC’s with bone marrow aspirate the most commonly being reported to stimulate healing.

Methods: This review examines the current reported 20 Q2 clinical applications of bone marrow aspirate concentrate and its effectiveness.

Results: The published studies reported techniques of collection and preparation of BMAC in addition to its applications in a number of orthopaedic sub-specialities. Studies could be sub-categorised into: techniques of extraction, processing and microscopic examination of BMAC (31), reconstruction of osseous defects/non-union (20), treatment of avascular necrosis (9), repair of cartilage defects (8), treatment of sports injuries and tendon injury/repair (9), injection in regenerative therapy (4), treatment of spine conditions (4) including enhancing postoperative fusion and degenerative disc pathology and orthopaedic oncology (4). A few published studies combined the use of platelet-rich plasma (PRP) with BMAC (4) or compared them in different applications (5).

Conclusions: BMAC has been used in bone, cartilage and tendon injuries with encouraging results.

The biology of bone lengthening

Distraction osteogenesis biologically resembles fracture healing with distinctive characteristics notably in the distraction phase of osteogenesis. In the latency phase of bone lengthening, like in the inflammatory phase of fracture repair, interleukines are released and act with growth factors released from platelets in the local haematoma, leading to attraction, proliferation and differentiation of mesenchymal stem cells into osteoblasts and other differentiated mesenchymal cells. These in turn produce matrix, collagen fibers and growth factors. A callus containing cells, collagen fibers, osteoid and cartilage matrix is formed. Provided stable fixation, distraction will trigger intramembranous bone formation. As distraction proceeds, the distraction gap develops five distinctive zones with unmineralized bone in the middle, remodelling bone peripherally, and mineralizing bone in between. During consolidation, the high concentration of anabolic growth factors in the regenerate diminishes with time as remodelling takes over to form mature cortical and cancellous bone. Systemic disease, congenital bone deficiencies, medications and substance abuse can influence the quality and quantity of regenerate bone, usually in a negative way. The regenerate bone can be manipulated when needed by using injection of mesenchymal stem cells and platelets, growth factors (BMP-2 and -7), and systemic medications (bisphosphonates and parathyroid hormone). Growth factors and systemic anabolic and antiresorptive drugs are prescribed on special indications, while distraction osteogenesis is not an authorized indication. To some extent, however, these compounds can be used off-label. Use in children presents special problems since growth factors and specific anabolic medications may involve a risk of inducing cancer.

Platelet-rich plasma for the treatment of bone defects: from pre-clinical rational to evidence in the clinical practice. A systematic review

PURPOSE

The treatment of large bone defects represents a significant challenge for orthopaedic surgeons. In recent years, biologic agents have also been used to further improve bone healing. Among these, platelet-rich plasma (PRP) is the most exploited strategy. The aim of the present study was to systematically review the available literature to identify: 1) preclinical in-vivo results supporting the rational of PRP use for bone healing; 2) evidence from the clinical practice on the actual clinical benefit of PRP for the treatment of fractures and complications such as delayed unions and non-unions.

METHODS

A systematic review of the literature was performed on the application of PRP in bone healing, using the following inclusion criteria: pre-clinical and clinical reports of any level of evidence, written in English language, published in the last 20 years (1996-2016), on the use of PRP to stimulate long-bone defect treatment, with focus on fracture and delayed/non-unions healing.

RESULTS

The search in the Pubmed database identified 64 articles eligible for inclusion: 45 were preclinical in-vivo studies and 19 were clinical studies. Despite the fact that the overall pre-clinical results seem to support the benefit of PRP in 91.1 % of the studies, a more in depth analysis underlined a lower success rate, with a positive outcome of 84.4 % in terms of histological analysis, and even lower values considering radiological and biomechanical results (75.0 % and 72.7 % positive outcome respectively). This was also mirrored in the clinical literature, where the real benefit of PRP use to treat fractures and non-unions is still under debate.

CONCLUSION

Overall, the available literature presents major limitations in terms of low quality and extreme heterogeneity, which hamper the possibility to optimize PRP treatment and translate it into a real clinical benefit despite positive preclinical findings on its biological potential to favour bone healing.

Regenerate bone stimulation following limb lengthening: a meta-analysis

Background

Limb lengthening with external fixation is performed to treat patients with leg length discrepancy or short stature. Although the procedure has a high rate of success, one potential drawback from limb lengthening is the amount of time spent in the fixation device while regenerate bone consolidates. Although some studies have assessed different treatment modalities, there has not been a study that has systematically evaluated whether low intensity pulsed ultrasound (LIPUS) or pulsed electromagnetic fields (PEMF) have significant effects on regenerate bone growth. The purpose of this study was to evaluate these two non-pharmacological treatment options to stimulate regenerate bone, and to assess whether they affect the treatment time in limb lengthening.

Methods

Utilizing the electronic databases Medline, Embase and Ovid, we performed a literature search for studies describing the application of LIPUS or PEMF following limb lengthening. With the aid of a statistical software package, Forest-Plots were generated to compare the differences in bone healing index with and without the use of regenerate bone stimulation.

Results

A total of 7 studies assessed these two bone stimulation modalities in a cohort of 153 patients. Overall, the mean healing index was 11.7 days/cm faster when using bone stimulation that in the comparison cohorts (33.7 vs 45.4 day, standardized mean difference of 1.16; p = 0.003).

Conclusion

Amongst the drawbacks from limb lengthening is the relatively high rate of non- and delayed-union. Several methods, both pharmacological and non-pharmacological, have been investigated for their potential to stimulate the growth of regenerate bone. After systematically evaluating the limited and heterogeneous current literature, we found that LIPUS and PEMF both decreased the time for bone healing (healing index in days/cm) of the newly formed regenerate bone in an adequately selected cohort of patients that underwent limb lengthening. However, a high number of complications should be noted, which could be attributed to the lengthening procedure or to the additional bone stimulation.

PROSPERO registration number

CRD42016039024

Electronic supplementary material

The online version of this article (doi:10.1186/s12891-016-1259-5) contains supplementary material, which is available to authorized users.