Concentrated bone marrow aspirate improves full-thickness cartilage repair compared with microfracture in the equine model

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.

Osteochondral lesions of the talus in the athlete: up to date review

PURPOSE OF REVIEW

Osteochondral lesions of the talus (OLT) are common injuries in athletes. The purpose of this study is to comprehensively review the clinical results and return to sport capacity in athletes following treatment for OLT.

RECENT FINDINGS

Reparative procedures, such as bone marrow stimulation, and replacement procedures, such as autologous osteochondral transplantation, provide good clinical outcomes in short- and mid-term follow-up in the athlete. Recently, biological augmentation and scaffold-based therapies have been shown to improve clinical and radiological outcomes in OLT in both the general population and athletes. Most studies are of a low level of evidence. Studies analyzing the return to sport capability in athletes are further lacking. High-level evidence and well-designed clinical trials are required to establish the most effective treatment protocol.

Current management of talar osteochondral lesions

Osteochondral lesions of the talus (OLT) occur in up to 70% of acute ankle sprains and fractures. OLT have become increasingly recognized with the advancements in cartilage-sensitive diagnostic imaging modalities. Although OLT may be treated nonoperatively, a number of surgical techniques have been described for patients whom surgery is indicated. Traditionally, treatment of symptomatic OLT have included either reparative procedures, such as bone marrow stimulation (BMS), or replacement procedures, such as autologous osteochondral transplantation (AOT). Reparative procedures are generally indicated for OLT < 150 mm2 in area. Replacement strategies are used for large lesions or after failed primary repair procedures. Although short- and medium-term results have been reported, long-term studies on OLT treatment strategies are lacking. Biological augmentation including platelet-rich plasma and concentrated bone marrow aspirate is becoming increasingly popular for the treatment of OLT to enhance the biological environment during healing. In this review, we describe the most up-to-date clinical evidence of surgical outcomes, as well as both the mechanical and biological concerns associated with BMS and AOT. In addition, we will review the recent evidence for biological adjunct therapies that aim to improve outcomes and longevity of both BMS and AOT procedures.

Evaluation and Management of Osteochondral Lesions of the Talus

Osteochondral lesions of the talus are common injuries that affect a wide variety of active patients. The majority of these lesions are associated with ankle sprains and fractures though several nontraumatic etiologies have also been recognized. Patients normally present with a history of prior ankle injury and/or instability. In addition to standard ankle radiographs, magnetic resonance imaging and computed tomography are used to characterize the extent of the lesion and involvement of the subchondral bone. Symptomatic nondisplaced lesions can often be treated conservatively within the pediatric population though this treatment is less successful in adults. Bone marrow stimulation techniques such as microfracture have yielded favorable results for the treatment of small (<15 mm) lesions. Osteochondral autograft can be harvested most commonly from the ipsilateral knee and carries the benefit of repairing defects with native hyaline cartilage. Osteochondral allograft transplant is reserved for large cystic lesions that lack subchondral bone integrity. Cell-based repair techniques such as autologous chondrocyte implantation and matrix-associated chondrocyte implantation have been increasingly used in an attempt to repair the lesion with hyaline cartilage though these techniques require adequate subchondral bone. Biological agents such as platelet-rich plasma and bone marrow aspirate have been more recently studied as an adjunct to operative treatment but their use remains theoretical. The present article reviews the current concepts in the evaluation and management of osteochondral lesions of the talus, with a focus on the available surgical treatment options.

Repair Potential of Matrix-Induced Bone Marrow Aspirate Concentrate and Matrix-Induced Autologous Chondrocyte Implantation for Talar Osteochondral Repair: Patterns of Some Catabolic, Inflammatory, and Pain Mediators

OBJECTIVE

The low regenerative potential of cartilage contributed to the development of different cell therapies aimed to improve the clinical outcome in young patients with Osteochondral Lesions of the Talus (OLT). This study is designed to assess the regenerative potential of autologous matrix-induced Bone Marrow Aspirate Concentrate (mBMAC) and matrix-induced Autologous Chondrocyte Implantation (mACI) evaluating, on a small number of osteochondral biopsies, the expression of some catabolic, inflammatory, and pain mediators.

DESIGN

Twenty-two patients with OLT were analyzed in this study; 7 were treated with mACI and 15 with mBMAC. Informed consent was obtained from all the patients. Clinical assessments were performed pre-operatively and at 12, 24, and 36 months after surgery using the American Orthopedic Foot and Ankle Society (AOFAS). Histology and immunohistochemistry were used to assess cartilage repair at 24 months. Data were analyzed using non-parametric Wilcoxon-Mann-Whitney and Spearman tests.

RESULTS

A remarkable improvement in AOFAS score was noticed for both treatments up to 36 months; however, patients treated with mACI reported the best AOFAS score. Various degrees of tissue remodeling were observed by histological analysis for both cell strategies. However, mBMAC treatment showed a higher expression of some fibrous and hypertrophic markers compared to mACI group. A mild positivity for nerve growth factor, as pain mediator, was noticed for both treatments.M.

CONCLUSIONS

Our findings demonstrated the best histological and clinical results following mACI treatment since different fibrotic and hypertrophic features were evident in the mBMAC group at 24-month follow-up.

Operative Treatment for Osteochondral Lesions of the Talus: Biologics and Scaffold-Based Therapy

OBJECTIVE

Numerous basic science articles have published evidence supporting the use of biologic augmentation in the treatment of osteochondral lesions of the talus (OLT). However, a comprehensive evaluation of the clinical outcomes of those treatment modalities in OLT has yet to be published. The purpose of this review is to provide an evidence-based overview of clinical outcomes following biologic augmentation to surgical treatments for OLT.

DESIGN

A comprehensive literature review was performed. Two commonly used surgical techniques for the treatment of OLT-bone marrow stimulation and osteochondral autograft transfer-are first introduced. The review describes the operative indications, step-by- step operative procedure, clinical outcomes, and concerns associated with each treatment. A review of the currently published basic science and clinical evidence on biologic augmentation in the surgical treatments for OLT, including platelet-rich plasma, concentrated bone marrow aspirate, and scaffold-based therapy follows.

RESULTS

Biologic agents and scaffold-based therapies appear to be promising agents, capable of improving both clinical and radiological outcomes in OLT. Nevertheless, variable production methods of these biologic augmentations confound the interpretation of clinical outcomes of cases treated with these agents.

CONCLUSIONS

Current clinical evidence supports the use of biologic agents in OLT cases. Nonetheless, well-designed clinical trials with patient-specific, validated and objective outcome measurements are warranted to develop standardized clinical guidelines for the use of biologic augmentation for the treatment of OLT in clinical practice.

Platelet-Rich Plasma and Concentrated Bone Marrow Aspirate in Surgical Treatment for Osteochondral Lesions of the Talus

Platelet-rich plasma (PRP) and concentrated bone marrow aspirate (CBMA) have the potential to improve the quality of cartilage repair in osteochondral lesions of the talus (OLT). In this review, we describe the basic science and clinical evidence that has been published on the topic of PRP and CBMA on 2 commonly used surgical techniques for the treatment of OLT: bone marrow stimulation and osteochondral autograft transfer.

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

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

Adipose Stromal Vascular Fraction-Mediated Improvements at Late-Stage Disease in a Murine Model of Multiple Sclerosis

Multiple sclerosis (MS) is a common neurodegenerative disease and remains an unmet clinical challenge. In MS, an autoimmune response leads to immune cell infiltration, inflammation, demyelination, and lesions in central nervous system (CNS) tissues resulting in tremors, fatigue, and progressive loss of motor function. These pathologic hallmarks are effectively reproduced in the murine experimental autoimmune encephalomyelitis (EAE) model. The stromal vascular fraction (SVF) of adipose tissue is composed of adipose-derived stromal/stem cells (ASC), adipocytes, and various leukocytes. The SVF can be culture expanded to generate ASC lines. Clinical trials continue to demonstrate the safety and efficacy of ASC therapies for treating several diseases. However, little is known about the effectiveness of the SVF for neurodegenerative diseases, such as MS. At late-stage disease, EAE mice show severe motor impairment. The goal for these studies was to test the effectiveness of SVF cells and ASC in EAE mice after the onset of neuropathology. The clinical scoring, behavior, motor function, and histopathologic analyses revealed significant improvements in EAE mice treated with the SVF or ASC. Moreover, SVF treatment mediated more robust improvements to CNS pathology than ASC treatment based on significant modulations of inflammatory factors. The most pronounced changes following SVF treatment were the high levels of interleukin-10 in the peripheral blood, lymphoid and CNS tissues along with the induction of regulatory T cells in the lymph nodes which indicate potent immunomodulatory effects. The data indicate SVF cells effectively ameliorated the EAE immunopathogenesis and supports the potential use of SVF for treating MS. Stem Cells 2017;35:532-544.

Bone marrow aspirate concentrate for the treatment of osteochondral lesions of the talus: a systematic review of outcomes

Background

The goal of this perform a systematic review on the outcomes of bone marrow aspirate concentrate (BMAC) for the treatment of chondral defects and osteoarthritis (OA) of the talus.

Results

The systematic search performed identified 47 studies after duplicates were removed. After inclusion criteria were applied four studies were considered for insightful analysis for the treatment of focal chondral defects in the foot and ankle with the use of BMAC. Three studies were retrospective and one study was prospective in nature. One study was a comparative cohort study and three studies were case series.

Conclusions

This review denotes that there exists an overwhelming paucity of long-term data and high-level evidence supporting BMAC for the treatment of chondral defects. Nonetheless, the evidence available showed varying degrees of beneficial results of BMAC for the treatment of ankle cartilage defects. The limited literature presented in this review demonstrates the need for more advanced, comparative studies to further investigate the efficacy, safety and techniques for BMAC in the treatment of OLTs. The authors recommend that BMAC therapy should be performed with careful consideration until the application and target population for this treatment are established.

Assessment of Methods for Rapid Intraoperative Concentration and Selection of Marrow-Derived Connective Tissue Progenitors for Bone Regeneration Using the Canine Femoral Multidefect Model

Treatment of large bone defects remains an unsolved clinical challenge, despite a wide array of existing bone graft materials and strategies. Local deficiency in osteogenic connective tissue progenitors (CTP-Os) due to tissue loss is one of the central biological barriers to bone regeneration. Density separation (DS) and selective retention (SR) represent two promising methods that can be used intraoperatively to rapidly concentrate cells and potentially select CTP-Os. This project was designed to compare DS and SR using the canine femoral multidefect (CFMD) model. Mineralized cancellous allograft (MCA) was used as a standardized scaffold for cell transplantation. Two experiments were performed using a cohort of six animals in each comparison. In Cohort I, unprocessed bone marrow aspirate (BMA) clot was compared to DS processing. MCA combined with raw BMA or DS processed cells produced a robust and advanced stage of bone regeneration throughout the defect in 4 weeks with reconstitution of hematopoietic marrow. However, the retention of DS processed cells and CTP-Os in the MCA matrix was low compared to BMA clot. In Cohort II, MCA with DS-T cells (addition of calcium chloride thrombin to induce clotting and enhance cell and CTP-O retention) was compared to MCA with SR cells. A mean of 276 ± 86 million nucleated cells and 29,030 ± 10,510 CTP-Os were implanted per defect in the DS-T group. A mean of 76 ± 42 million nucleated cells and 30,266 ± 15,850 CTP-Os were implanted in the SR group. Bone formation was robust and not different between treatments. Histologically, both groups demonstrated regeneration of hematopoietic marrow tissue. However, SR sites contained more hematopoietic vascular tissues, less fibrosis, and less residual allograft, particularly in the intramedullary cavity, suggesting a more advanced stage of remodeling (p = 0.04). These data demonstrate excellent overall performance of DS and SR processing methods. Both methods achieve a bone regeneration response that approaches the limits of performance that can be achieved in the CFMD model. Further advancement and comparison of these intraoperative bone marrow cell processing methods will require use of a larger and more biologically compromised defect site to guide the next steps of preclinical development and optimization.

Utility of a Mouse Model of Osteoarthritis to Demonstrate Cartilage Protection by IFNγ-Primed Equine Mesenchymal Stem Cells

Objective

Mesenchymal stem cells isolated from adipose tissue (ASC) have been shown to influence the course of osteoarthritis (OA) in different animal models and are promising in veterinary medicine for horses involved in competitive sport. The aim of this study was to characterize equine ASCs (eASCs) and investigate the role of interferon-gamma (IFNγ)-priming on their therapeutic effect in a murine model of OA, which could be relevant to equine OA.

Methods

ASC were isolated from subcutaneous fat. Expression of specific markers was tested by cytometry and RT-qPCR. Differentiation potential was evaluated by histology and RT-qPCR. For functional assays, naïve or IFNγ-primed eASCs were cocultured with peripheral blood mononuclear cells or articular cartilage explants. Finally, the therapeutic effect of eASCs was tested in the model of collagenase-induced OA (CIOA) in mice.

Results

The immunosuppressive function of eASCs on equine T cell proliferation and their chondroprotective effect on equine cartilage explants were demonstrated in vitro. Both cartilage degradation and T cell activation were reduced by naïve and IFNγ-primed eASCs, but IFNγ-priming enhanced these functions. In CIOA, intra-articular injection of eASCs prevented articular cartilage from degradation and IFNγ-primed eASCs were more potent than naïve cells. This effect was related to the modulation of eASC secretome by IFNγ-priming.

Conclusion

IFNγ-priming of eASCs potentiated their antiproliferative and chondroprotective functions. We demonstrated that the immunocompetent mouse model of CIOA was relevant to test the therapeutic efficacy of xenogeneic eASCs for OA and confirmed that IFNγ-primed eASCs may have a therapeutic value for musculoskeletal diseases in veterinary medicine.

Fresh Osteochondral Allograft Versus Autograft: Twelve-Month Results in Isolated Canine Knee Defects

BACKGROUND

Osteochondral autografts and allografts have been widely used in the treatment of isolated grade 4 articular cartilage lesions of the knee. However, there is a paucity of literature regarding the basic science investigating the direct comparison between fresh osteochondral allografts to autografts.

HYPOTHESIS

At 12 months, fresh osteochondral allografts are equal to autografts with respect to function, bony incorporation into host bone, and chondrocyte viability.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eight adult mongrel dogs underwent bilateral hindlimb osteochondral graft implantation in the knee after creation of an acute Outerbridge grade 4 cartilage defect. One hindlimb of each dog knee received an autograft, and the contralateral knee received an allograft. All dogs were sacrificed at 12 months. Graft analysis included gross examination, radiographs, magnetic resonance imaging (MRI), biomechanical testing, and histology.

RESULTS

MRI demonstrated excellent bony incorporation of both autografts and allografts, except for 1 allograft that revealed partial incorporation. Histologic examination of cartilage showed intact hyaline appearance for both autografts and allografts, with fibrocartilage at the host-graft interface of both. Biomechanical testing demonstrated no significant difference between allografts and autografts (P = .76). Furthermore, no significant difference was observed between allografts and the native cartilage with biomechanical testing (P = .84).

CONCLUSION

After 12 months from time of implantation, fresh osteochondral allograft tissue and autograft tissue in this study were not statistically different with respect to biomechanical properties, gross morphology, bony incorporation, or overall histologic characteristics. When compared with the previously reported 6-month incorporation rates, there was improved allograft and autograft incorporation at 12 months.

CLINICAL RELEVANCE

With no significant differences in gross examination, radiographs, MRI, biomechanical testing, or histology in the canine model, the use of allograft tissue to treat osteochondral defects may eliminate the morbidity associated with autograft harvest.

Diagnosis and treatment of osteochondral lesions of the ankle: current concepts

We conducted a wide-ranging review of the literature regarding osteochondral lesions of the ankle, with the aim of presenting the current concepts, treatment options, trends and future perspectives relating to this topic.

Bone Marrow Aspirate in the Treatment of Chondral Injuries

The ability of mesenchymal stem cells (MSCs) to transdifferentiate into a desired cell lineage has captured the imagination of scientists and clinicians alike. The limited ability for chondrocytes to regenerate in chondral injuries has raised the concept of using MSCs to help regenerate and repair damaged tissue. The expansion of cells in a laboratory setting to be delivered back to the patient is too costly for clinical use in the present tough economic climate. This process is slow with due to the complexity of trying to imitate the natural environment and biological stimulation of chondral cell replication and proliferation. Bone marrow aspirate concentrate (BMAC) has the potential to provide an easily accessible and readily available source of MSCs with key growth factors that can be used in treating chondral injuries. This review summarizes the underlying basic science of MSCs and the therapeutic potential of BMAC.

Recent Advances in Egypt for Treatment of Talar Osteochondral Lesions

Treatment of osteochondral defects (OCLs) of the talus is a challenging orthopedic surgery. Treatment of talar OCLs has evolved through the 3 "R" paradigm: reconstruction, repair, and replacement. This article highlights current state-of-the-art techniques and reviews recent advances in the literature about articular cartilage repair using various novel tissue engineering approaches, including various scaffolds, growth factors, and cell niches; which include chondrocytes and culture-expanded bone marrow-derived mesenchymal stem cells.

Additional mesenchymal stem cell injection improves the outcomes of marrow stimulation combined with supramalleolar osteotomy in varus ankle osteoarthritis: short-term clinical results with second-look arthroscopic evaluation

Background

Supramalleolar osteotomy (SMO) is reported to be an effective treatment for varus ankle osteoarthritis by redistributing the load line within the ankle joint. Mesenchymal stem cells (MSCs) have been proposed as a new treatment option for osteoarthritis on the basis of their cartilage regeneration ability. The purpose of this study was to compare the clinical, radiological, and second-look arthroscopic outcomes between MSC injection with marrow stimulation and marrow stimulation alone in patients with varus ankle osteoarthritis who have undergone SMO.

Methods

In this retrospective study, 62 patients (64 ankles) with varus ankle osteoarthritis underwent second-look arthroscopy at a mean of 12.8 months after arthroscopic marrow stimulation combined with SMO; 33 ankles were subjected to marrow stimulation alone (group I), and 31 were subjected to marrow stimulation with MSC injection (group II). Clinical outcome measures included a visual analog scale (VAS) for pain and the American Orthopaedic Foot and Ankle Society (AOFAS) score. Radiological outcome variables included the tibial–ankle surface (TAS), talar tilt (TT), and tibial–lateral surface (TLS) angles. In second-look arthroscopy, cartilage regeneration was evaluated using the International Cartilage Repair Society (ICRS) grade.

Results

The mean VAS score improved significantly from 7.2 ± 1.0 to 4.7 ± 1.4 in group I and from 7.3 ± 0.8 to 3.7 ± 1.5 in group II at the final follow-up (P < 0.001 for both groups). The mean AOFAS score also improved significantly from 61.7 ± 5.8 to 80.9 ± 6.7 in group I and from 60.6 ± 6.1 to 85.2 ± 5.1 in group II at the final follow-up (P < 0.001 for both groups). There were significant differences in the mean VAS and AOFAS scores between groups at the final follow-up (P = 0.002 and 0.010, respectively). At second-look arthroscopy, there were significant differences in ICRS grades between groups(P = 0.015 for medial aspect of the talar dome, P = 0.044 for medial aspect of the tibial plafond, and P = 0.005 for articular surface of the medial malleolus). ICRS grades were significantly correlated with clinical outcomes in both groups (all P < 0.05). Mean TAS, TT, and TLS angles improved significantly after SMO in both groups but were not significantly correlated with clinical outcomes or ICRS grade (all n.s.).

Conclusions

The clinical and second-look arthroscopic outcomes of MSC injection with marrow stimulation were better compared to those of marrow stimulation alone in patients with varus ankle osteoarthritis who have undergone SMO. Furthermore, the ICRS grade is significantly correlated with clinical outcome.

Research trends in biomimetic medical materials for tissue engineering: 3D bioprinting, surface modification, nano/micro-technology and clinical aspects in tissue engineering of cartilage and bone

This review discusses about biomimetic medical materials for tissue engineering of bone and cartilage, after previous scientific commentary of the invitation-based, Korea-China joint symposium on biomimetic medical materials, which was held in Seoul, Korea, from October 22 to 26, 2015. The contents of this review were evolved from the presentations of that symposium. Four topics of biomimetic medical materials were discussed from different research groups here: 1) 3D bioprinting medical materials, 2) nano/micro-technology, 3) surface modification of biomaterials for their interactions with cells and 4) clinical aspects of biomaterials for cartilage focusing on cells, scaffolds and cytokines.

Management of knee articular cartilage injuries in athletes: chondroprotection, chondrofacilitation, and resurfacing

Articular cartilage defects of the knee are common among athletes where the physical demands of sport result in significant stresses on joints. Chondral defects are associated with pain and functional impairment that limit sporting participation and may progress to joint degeneration and frank arthritis. Management of established chondral lesions aims to allow athletes to return to high-impact sports and can be considered in terms of protection of existing cartilage, chondrofacilitation, and resurfacing. Repaired and regenerated cartilage must closely resemble and function like normal hyaline cartilage, and this ability may be the most significant factor for the return to sport. Based on our experiences and the available literature, we outline how athletes can best protect their cartilage, how physicians can facilitate intrinsic repair of established lesions, and which methods of cartilage restoration or resurfacing should be used in different situations.

LEVEL OF EVIDENCE

IV.

Second-look assessment after all-arthroscopic autologous chondrocyte implantation with spheroides at the knee joint

PURPOSE

To report arthroscopic second look as well as clinical results after arthroscopic autologous chondrocyte implantation (ACI) for articular cartilage repair at the knee joint.

METHODS

A second-look assessment after arthroscopic ACI using spheroides was performed in 41 patients with 57 full-size articular cartilage defects of the knee. The median time from ACI to second-look arthroscopy was 10 (6-72) months. The ACI was assessed macroscopically and by probing according to the International Cartilage Repair Score (ICRS)-Cartilage Repair Assessment (CRA) to get information on the amount and quality of regeneration. Clinical follow-up with subjective outcome scores was performed an average of 34.5 ± 19.2 months after ACI. Twenty-seven (65.8 %) of ACI's were combined with additional procedures.

RESULTS

The ICRS-CRA was rated "normal" or "nearly normal" in 52 of 57 (91.3 %) and "abnormal" in 5 (8.8 %) of all cartilage defects. At follow-up, evaluation of KOOS was an average of 81.0 ± 12.9 for pain, 76.8 ± 16.6 for symptoms, 85.1 ± 14.9 for activities of daily living, 55.3 ± 27.7 for sport and recreation and 50.6 ± 23.8 for quality of live. IKDC was 63.0 ± 18.8, Lysholm score was 79.0 ± 18.0, and Tegner score was 4 (1-6). Subjective assessment according to the VAS scale was an average of 7.4 ± 2.1 for overall satisfaction and 6.7 ± 2.5 satisfaction for the operated knee. Seven patients (22.6 %) showed low subjective outcome scores at last follow-up-of these, 2 patients showed a CRA 3 and 5 a CRA 1 or 2.

CONCLUSION

At second-look arthroscopy, 52 (91.3 %) of all cartilage defects showed a normal or nearly normal macroscopic articular cartilage regeneration after arthroscopic ACI using spheroides. Twenty-four patients (77.4 %) showed good subjective clinical results. The high number of concomitant surgery reflexes the complex aetiology of cartilage lesions and complexity of treatment. Thus, a strict indication and surgical planing is necessary to avoid clinical failures.

LEVEL OF EVIDENCE

IV.

Injection of Mesenchymal Stem Cells as a Supplementary Strategy of Marrow Stimulation Improves Cartilage Regeneration After Lateral Sliding Calcaneal Osteotomy for Varus Ankle Osteoarthritis: Clinical and Second-Look Arthroscopic Results

PURPOSE

To compare the clinical and second-look arthroscopic outcomes in patients undergoing arthroscopic marrow stimulation combined with lateral sliding calcaneal osteotomy for varus ankle osteoarthritis, with or without adipose-derived mesenchymal stem cell (MSC) injection.

METHODS

In this retrospective comparative study, 49 patients with varus ankle osteoarthritis underwent second-look arthroscopy after arthroscopic marrow stimulation combined with lateral sliding calcaneal osteotomy between January 2010 and November 2012; 23 ankles underwent marrow stimulation alone (group 1), and 26 underwent marrow stimulation with MSC injection (group 2). The decision whether to receive the MSC injection, which was free of charge, was solely up to the patients. Second-look arthroscopies were performed at a mean of 12.5 months and 12.4 months postoperatively in group 1 and group 2, respectively. Clinical outcome measures included a visual analog scale (VAS) score for pain and the American Orthopaedic Foot & Ankle Society (AOFAS) score. The radiologic outcome variable was the talar tilt angle. On second-look arthroscopy, cartilage regeneration was evaluated using the International Cartilage Repair Society (ICRS) grade.

RESULTS

The mean VAS score improved significantly from 7.3 ± 0.9 to 3.9 ± 1.2 in group 1 and from 7.4 ± 0.8 to 3.1 ± 1.5 in group 2 at final follow-up (P < .001 for both groups). The mean AOFAS score also improved significantly from 64.4 ± 4.1 to 79.6 ± 7.7 in group 1 and from 63.5 ± 4.2 to 84.2 ± 7.9 in group 2 at final follow-up (P < .001 for both groups). The VAS and AOFAS scores were significantly better in group 2 than in group 1 (P = .040 and P = .047, respectively). ICRS grades were significantly correlated with clinical outcomes in both groups (all P < .05), and there were significant differences in ICRS grades between the groups (P < .05). The mean talar tilt angle improved significantly after lateral sliding calcaneal osteotomy in both groups and was significantly correlated with clinical outcomes and ICRS grade (all P < .05).

CONCLUSIONS

In patients with varus ankle osteoarthritis who underwent lateral sliding calcaneal osteotomy, significant improvements in VAS and AOFAS scores, as well as better ICRS grades, were achieved at short-term follow-up after marrow stimulation with additional MSC injection compared with after marrow stimulation alone.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Biologic Treatments for Sports Injuries II Think Tank-Current Concepts, Future Research, and Barriers to Advancement, Part 3: Articular Cartilage

Focal chondral defects of the articular surface are a common occurrence in the field of orthopaedics. These isolated cartilage injuries, if not repaired surgically with restoration of articular congruency, may have a high rate of progression to posttraumatic osteoarthritis, resulting in significant morbidity and loss of function in the young, active patient. Both isolated and global joint disease are a difficult entity to treat in the clinical setting given the high amount of stress on weightbearing joints and the limited healing potential of native articular cartilage. Recently, clinical interest has focused on the use of biologically active compounds and surgical techniques to regenerate native cartilage to the articular surface, with the goal of restoring normal joint health and overall function. This article presents a review of the current biologic therapies, as discussed at the 2015 American Orthopaedic Society for Sports Medicine (AOSSM) Biologics Think Tank, that are used in the treatment of focal cartilage deficiencies. For each of these emerging therapies, the theories for application, the present clinical evidence, and specific areas for future research are explored, with focus on the barriers currently faced by clinicians in advancing the success of these therapies in the clinical setting.

Biopsy Needle Advancement during Bone Marrow Aspiration Increases Mesenchymal Stem Cell Concentration

Point-of-care kits to concentrate bone marrow (BM)-derived mesenchymal stem cells (MSCs) are used clinically in horses. A maximal number of MSCs per milliliter of marrow aspirated might be desired prior to use of a point-of-care system to concentrate MSCs. Our objective was to test a method to increase the number of MSCs per milliliter of marrow collected. We collected two BM aspirates using two different collection techniques from 12 horses. The first collection technique was to aspirate BM from a single site without advancement of the biopsy needle. The second collection technique was to aspirate marrow from multiple sites within the same sternal puncture by advancing the needle 5 mm three times for BM aspiration from four sites. Numbers of MSCs in collected BM were assessed by total nucleated cell count of BM after aspiration, total colony-forming unit-fibroblast (CFU-F) assay, and total MSC number at each culture passage. The BM aspiration technique of four needle advancements during BM aspiration resulted in higher initial nucleated cell counts, more CFU-Fs, and more MSCs at the first passage. There were no differences in the number of MSCs at later passages. Multiple advancements of the BM needle during BM aspiration resulted in increased MSC concentration at the time of BM collection. If a point-of-care kit is used to concentrate MSCs, multiple advancements may result in higher MSC numbers in the BM concentrate after preparation by the point-of-care kit. For culture expanded MSCs beyond the first cell passage, the difference is of questionable clinical relevance.

Cartilage defect repair in horses: Current strategies and recent developments in regenerative medicine of the equine joint with emphasis on the surgical approach

Chondral and osteochondral lesions due to injury or other pathology are highly prevalent conditions in horses (and humans) and commonly result in the development of osteoarthritis and progression of joint deterioration. Regenerative medicine of articular cartilage is an emerging clinical treatment option for patients with articular cartilage injury or disease. Functional articular cartilage restoration, however, remains a major challenge, but the field is progressing rapidly and there is an increasing body of supportive clinical and scientific evidence. This review gives an overview of the established and emerging surgical techniques employed for cartilage repair in horses. Through a growing insight in surgical cartilage repair possibilities, surgeons might be more stimulated to explore novel techniques in a clinical setting.

Arthroscopic Bone Marrow Stimulation and Concentrated Bone Marrow Aspirate for Osteochondral Lesions of the Talus: A Case-Control Study of Functional and Magnetic Resonance Observation of Cartilage Repair Tissue Outcomes

PURPOSE

This study compares retrospective functional and magnetic resonance imaging (MRI) outcomes after arthroscopic bone marrow stimulation (BMS) with and without concentrated bone marrow aspirate (cBMA) as a biological adjunct to the surgical treatment of osteochondral lesions (OCLs) of the talus.

METHODS

Twenty-two patients who underwent arthroscopic BMS with cBMA (cBMA/BMS group) for an osteochondral lesion (OCL) of the talus and 12 patients who underwent arthroscopic BMS (BMS alone) for an OCL of the talus were retrospectively reviewed. The Foot and Ankle Outcome Score (FAOS) pain subscale and Short Form 12 general health questionnaire physical component summary score (SF-12 PCS) provided patient-reported outcome scores pre- and postoperatively. MRI scans were assessed postoperatively using the magnetic resonance observation of cartilage repair tissue (MOCART) score. All patients had postoperative MRI performed at the 2-year postoperative visit, and quantitative T2 mapping relaxation time values were assessed in a subset of the cBMA/BMS group.

RESULTS

The mean FAOS and SF-12 PCS scores improved significantly pre- to post-operatively (P < .01) at a mean follow-up of 48.3 months (range, 34 to 82 months) for the cBMA/BMS group and 77.3 months (range, 46 to 100 months) for the BMS-alone group. The MOCART score in the cBMA/BMS group was significantly higher than that in the BMS-alone group (P = .023). Superficial and deep T2 relaxation values in cBMA/BMS patients were higher in repair tissue compared with measurements in adjacent native articular cartilage (P = .030 and P < .001, respectively).

CONCLUSIONS

BMS is an effective treatment strategy for treatment of OCLs of the talus and results in good medium-term functional outcomes. Arthroscopic BMS with cBMA also results in similar functional outcomes and improved border repair tissue integration, with less evidence of fissuring and fibrillation on MRI.

Football injuries of the ankle: A review of injury mechanisms, diagnosis and management

Football is the most popular sport worldwide and is associated with a high injury rate, most of which are the result of trauma from player contact. Ankle injuries are among the most commonly diagnosed injuries in the game. The result is reduced physical activity and endurance levels, lost game time, and considerable medical cost. Sports medicine professionals must employ the correct diagnostic tools and effective treatments and rehabilitation protocols to minimize the impact of these injuries on the player. This review examines the diagnosis, treatment, and postoperative rehabilitation for common football injuries of the ankle based on the clinical evidence provided in the current literature.

Concentrated Bone Marrow Aspirate for the Treatment of Chondral Injuries and Osteoarthritis of the Knee: A Systematic Review of Outcomes

Background:

Bone marrow aspirate concentrate (BMAC) has emerged as a novel treatment for pathology of the knee. Despite containing a limited number of stem cells, BMAC serves as a source of growth factors that are thought to play an important role as a result of their anabolic and anti-inflammatory effects. To our knowledge, there is no systematic review regarding the outcomes of bone marrow aspirate concentrate used for the treatment of chondral defects and osteoarthritis of the knee.

Purpose:

To perform a systematic review on the outcomes of bone marrow aspirate concentrate for the treatment of chondral defects and osteoarthritis of the knee.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review of the literature was performed using the Cochrane Database of Systematic Reviews, the Cochrane Central Register of Controlled Trials, PubMed, and MEDLINE from 1980 to present. Inclusion criteria were as follows: use of BMAC for treatment of chondral defects and osteoarthritis of the knee, English language, and human studies. We excluded cadaveric studies, animal studies, basic science articles, editorial articles, surveys, and studies that did not include the knee. After applying inclusion and exclusion criteria, studies were evaluated for efficacy and safety of BMAC for treatment of articular cartilage knee pathologies.

Results:

Eleven studies were considered. Of these, 5 were prospective studies, 1 was a retrospective study, 2 were case series, and 3 were case reports. Three comparative studies (2 with level 2 evidence, 1 with level 3 evidence) were found in our search; none of them were randomized. Three studies investigated the clinical efficacy of BMAC in the treatment of osteoarthritis, and 8 studies evaluated the efficacy of BMAC on focal cartilage injuries. All 3 studies regarding osteoarthritis and all 8 studies regarding focal chondral defects reported good to excellent overall outcomes with the use of BMAC.

Conclusion:

Although a growing interest for biological alternatives of treating knee pathology has been observed in the past few years, there still remains a paucity of high-quality studies. The studies included in this systematic review reported varying degrees of beneficial results with the use of BMAC with and without an additional procedure for the treatment of chondral defects and early stages of osteoarthritis. Most articles present the use of BMAC as a safe procedure and report good results.

Addition of Mesenchymal Stem Cells to Autologous Platelet-Enhanced Fibrin Scaffolds in Chondral Defects: Does It Enhance Repair?

BACKGROUND

The chondrogenic potential of culture-expanded bone-marrow-derived mesenchymal stem cells (BMDMSCs) is well described. Numerous studies have also shown enhanced repair when BMDMSCs, scaffolds, and growth factors are placed into chondral defects. Platelets provide a rich milieu of growth factors and, along with fibrin, are readily available for clinical use. The objective of this study was to determine if the addition of BMDMSCs to an autologous platelet-enriched fibrin (APEF) scaffold enhances chondral repair compared with APEF alone.

METHODS

A 15-mm-diameter full-thickness chondral defect was created on the lateral trochlear ridge of both stifle joints of twelve adult horses. In each animal, one defect was randomly assigned to receive APEF+BMDMSCs and the contralateral defect received APEF alone. Repair tissues were evaluated one year later with arthroscopy, histological examination, magnetic resonance imaging (MRI), micro-computed tomography (micro-CT), and biomechanical testing.

RESULTS

The arthroscopic findings, MRI T2 map, histological scores, structural stiffness, and material stiffness were similar (p > 0.05) between the APEF and APEF+BMDMSC-treated repairs at one year. Ectopic bone was observed within the repair tissue in four of twelve APEF+BMDMSC-treated defects. Defects repaired with APEF alone had less trabecular bone edema (as seen on MRI) compared with defects repaired with APEF+BMDMSCs. Micro-CT analysis showed thinner repair tissue in defects repaired with APEF+BMDMSCs than in those treated with APEF alone (p < 0.05).

CONCLUSIONS

APEF alone resulted in thicker repair tissue than was seen with APEF+BMDMSCs. The addition of BMDMSCs to APEF did not enhance cartilage repair and stimulated bone formation in some cartilage defects.

CLINICAL RELEVANCE

APEF supported repair of critical-size full-thickness chondral defects in horses, which was not improved by the addition of BMDMSCs. This work supports further investigation to determine whether APEF enhances cartilage repair in humans.

Bone Marrow Concentrate Improves Early Cartilage Phase Maturation of a Scaffold Plug in the Knee: A Comparative Magnetic Resonance Imaging Analysis to Platelet-Rich Plasma and Control

BACKGROUND

Limited information exists on the clinical use of a synthetic osteochondral scaffold plug for cartilage restoration in the knee.

PURPOSE/HYPOTHESIS

The purpose of this study was to compare the early magnetic resonance imaging (MRI) appearance, including quantitative T2 values, between cartilage defects treated with a scaffold versus a scaffold with platelet-rich plasma (PRP) or bone marrow aspirate concentrate (BMAC). The hypothesis was that the addition of PRP or BMAC would result in an improved cartilage appearance.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Forty-six patients with full-thickness cartilage defects of the femur were surgically treated with a control scaffold (n = 11), scaffold with PRP (n = 23), or scaffold with BMAC (n = 12) and were followed prospectively. Patients underwent MRI with a qualitative assessment and quantitative T2 mapping at 12 months after surgery. An image assessment was performed retrospectively by a blinded musculoskeletal radiologist. The cartilage phase was measured by cartilage fill and quantitative T2 values on MRI. A comparison between groups after cartilage repair was performed.

RESULTS

The control scaffold group consisted of 8 male and 3 female patients (mean age, 38 years; mean body mass index [BMI], 25 kg/m(2)), the PRP group had 15 male and 8 female patients (mean age, 39 years; mean BMI, 26 kg/m(2)), and the BMAC group consisted of 8 male and 4 female patients (mean age, 36 years; mean BMI, 26 kg/m(2)). The PRP-treated (P = .002) and BMAC-treated (P = .03) scaffolds had superior cartilage fill compared with the control group. With quantitative methods, the PRP group demonstrated a mean T2 value (49.1 ms) that was similar to that of the control scaffold group (42.7 ms; P = .07), but the BMAC group demonstrated a mean T2 value (60.5 ms) closer to that of superficial hyaline cartilage (P = .01). The stratification of T2 values between the deep and superficial zones was not observed in any of the groups.

CONCLUSION

In this comparative study, patients treated with scaffold implantation augmented with BMAC had improved cartilage maturation with greater fill and mean T2 values closer to that of superficial native hyaline cartilage at 12 months. Further work will determine if this translates into improved clinical outcomes.

Autologous bone-marrow mesenchymal cell induced chondrogenesis (MCIC)

Degenerative and traumatic articular cartilage defects are common, difficult to treat, and progressive lesions that cause significant morbidity in the general population. There have been multiple approaches to treat such lesions, including arthroscopic debridement, microfracture, multiple drilling, osteochondral transplantation and autologous chondrocyte implantation (ACI) that are currently being used in clinical practice. Autologous bone-marrow mesenchymal cell induced chondrogenesis (MCIC) is a single-staged arthroscopic procedure. This method combines a modified microfracture technique with the application of a bone marrow aspirate concentrate (BMAC), hyaluronic acid and fibrin gel to treat articular cartilage defects. We reviewed the current literatures and surgical techniques for mesenchymal cell induced chondrogenesis.

Cell-based cartilage repair strategies in the horse

Damage to the articular cartilage surface is common in the equine athlete and, due to the poor intrinsic healing capabilities of cartilage, can lead to osteoarthritis (OA). Joint disease and OA are the leading cause of retirement in equine athletes and currently there are no effective treatments to stop the progression of OA. Several different cell-based strategies have been investigated to bolster the weak regenerative response of chondrocytes. Such techniques aim to restore the articular surface and prevent further joint degradation. Cell-based cartilage repair strategies include enhancement of endogenous repair mechanisms by recruitment of stem cells from the bone marrow following perforation of the subchondral bone plate; osteochondral implantation; implantation of chondrocytes that are maintained in defects by either a membrane cover or scaffold, and transplantation of mesenchymal stem cells into cartilage lesions. More recently, bioengineered cartilage and scaffoldless cartilage have been investigated for enhancing repair. This review article focuses on the multitude of cell-based repair techniques for cartilage repair across several species, with special attention paid to the horse.

Pulsed electromagnetic fields combined with a collagenous scaffold and bone marrow concentrate enhance osteochondral regeneration: an in vivo study

BACKGROUND

The study aimed to evaluate the combined effect of Pulsed Electromagnetic Field (PEMF) biophysical stimulation and bone marrow concentrate (BMC) in osteochondral defect healing in comparison to the treatment with scaffold alone.

METHODS

An osteochondral lesion of both knees was performed in ten rabbits. One was treated with a collagen scaffold alone and the other with scaffold seeded with BMC. Half of the animals were stimulated by PEMFs (75 Hz, 1.5 mT, 4 h/day) and at 40 d, macroscopic, histological and histomorphometric analyses were performed to evaluate osteochondral defect regeneration.

RESULTS

Regarding cartilage, the addition of BMC to the scaffold improved cell parameters and the PEMF stimulation improved both cell and matrix parameters compared with scaffold alone. The combination of BMC and PEMFs further improved osteochondral regeneration: there was an improvement in macroscopic, cartilage cellularity and matrix parameters and a reduction in the percentage of cartilage under the tidemark. Epiphyseal bone healing improved in all the osteochondral defects regardless of treatment, although PEMFs alone did not significantly improve the reconstruction of subchondral bone in comparison to treatment with scaffold alone.

CONCLUSIONS

Results show that BMC and PEMFs might have a separate effect on osteochondral regeneration, but it seems that they have a greater effect when used together. Biophysical stimulation is a non-invasive therapy, free from side effects and should be started soon after BMC transplantation to increase the quality of the regenerated tissue. However, because this is the first explorative study on the combination of a biological and a biophysical treatment for osteochondral regeneration, future preclinical and clinical research should be focused on this topic to explore mechanisms of action and the correct clinical translation.

The current 'state of play' of regenerative medicine in horses: what the horse can tell the human

The horse is an attractive model for many human age-related degenerative diseases of the musculoskeletal system because it is a large animal species that both ages and exercises, and develops naturally occurring injuries with many similarities to the human counterpart. It therefore represents an ideal species to use as a 'proving ground' for new therapies, most notably regenerative medicine. Regenerative techniques using cell-based therapies for the treatment of equine musculoskeletal disease have been in use for over a decade. This review article provides a summary overview of the sources, current challenges and problems surrounding the use of stem cell and non-cell-based therapy in regenerative medicine in horses and is based on presentations from a recent Havemeyer symposium on equine regenerative medicine where speakers are selected from leading authorities in both equine and human regenerative medicine fields from 10 different countries.

Monitoring the Progression of Spontaneous Articular Cartilage Healing with Infrared Spectroscopy

OBJECTIVE

Evaluation of early compositional changes in healing articular cartilage is critical for understanding tissue repair and for therapeutic decision-making. Fourier transform infrared imaging spectroscopy (FT-IRIS) can be used to assess the molecular composition of harvested repair tissue. Furthermore, use of an infrared fiber-optic probe (IFOP) has the potential for translation to a clinical setting to provide molecular information in situ. In the current study, we determined the feasibility of IFOP assessment of cartilage repair tissue in a rabbit model, and assessed correlations with gold-standard histology.

DESIGN

Bilateral osteochondral defects were generated in mature white New Zealand rabbits, and IFOP data obtained from defect and adjacent regions at 2, 4, 6, 8, 12, and 16 weeks postsurgery. Tissues were assessed histologically using the modified O'Driscoll score, by FT-IRIS, and by partial least squares (PLS) modeling of IFOP spectra.

RESULTS

The FT-IRIS parameters of collagen content, proteoglycan content, and collagen index correlated significantly with modified O'Driscoll score (P = 0.05, 0.002, and 0.02, respectively), indicative of their sensitivity to tissue healing. Repair tissue IFOP spectra were distinguished from normal tissue IFOP spectra in all samples by PLS analysis. However, the PLS model for prediction of histological score had a high prediction error, which was attributed to the spectral information being acquired from the tissue surface only.

CONCLUSION

The strong correlations between FT-IRIS data and histological score support further development of the IFOP technique for clinical applications, although further studies to optimize data collection from the full sample depths are required.

Biologic adjuvants and bone: current use in orthopedic surgery

Normal bone healing is a complex process that eventually restores original structure and function to the site of trauma. However, clinical circumstances such as nonunion, critical-sized defects, systemic bone disease, and fusion procedures have stimulated a search for ways to enhance this normal healing process. Biologics are an important part of this search and many, including bone marrow aspirate concentrate, demineralized bone matrix, platelet-rich plasma, bone morphogenic proteins, and platelet-derived growth factor, are currently in clinical use. Many others, including mesenchymal stem cells, parathyroid hormone, and Nel-like molecule-1 (NELL-1) will likely be in use in the future depending on the results of preclinical and clinical trials.

Matrix-Induced Autologous Chondrocyte Implantation versus Multipotent Stem Cells for the Treatment of Large Patellofemoral Chondral Lesions: A Nonrandomized Prospective Trial

OBJECTIVE

To compare the outcome of matrix-induced autologous chondrocyte implantation (MACI) and bone marrow aspirate concentrate (BMAC)-derived multipotent stem cells (MSCs) implantation in patellofemoral chondral lesions, using the same HYAFF11 scaffold.

METHODS

From January 2005 to December 2010, 37 patients with patellofemoral chondral lesions were prospectively followed up, for a minimum of 3 years; 19 of these patients were treated with MACI and 18 with BMAC. Radiographs, magnetic resonance imaging, and clinical scores (International Knee Documentation Committee, Knee Injury and Osteoarthritis Outcome Score, visual analog scale, and Tegner) were collected preoperatively, at 2-year and final follow-up. Five patients of MACI and 6 of the BMAC group underwent second-look arthroscopy; 4 patients of each group consented to a concomitant biopsy.

RESULTS

No adverse reactions or postoperative infections were noted. Baseline characteristics were similar in both groups (P > 0.05). Both groups showed significant improvement in all scores, from preoperative to final follow-up (P = 0.001), but there was no significant difference in improvement between the 2 groups, except for the IKDC subjective score (P = 0.015), which favored the BMAC group. Deterioration in MACI and improvement in BMAC group scores were noticed, from 2-year to final follow-up, but was nonsignificant. MACI patients with trochlear lesions showed better results than patellar lesions, while location was not a prognostic factor in the BMAC group. MRI showed complete filling of the defects in 76% of patients in MACI and 81% of patients in BMAC, and histological analysis revealed hyaline-like features.

CONCLUSION

Both techniques are viable and effective for large patellofemoral chondral lesions at minimum 3-year follow-up.

The Challenge and the Promise of Bone Marrow Cells for Human Cartilage Repair

The cartilage repair potential of bone marrow-derived stem cells has been well described. Harnessing this potential for human articular cartilage repair remains challenging. Accessing bone marrow repair cells through marrow stimulation techniques such as microfracture is readily achieved with generally good but inconsistent results. Animal and human studies show feasibility for ex vivo processing of bone marrow to isolate, concentrate, and culture mesenchymal stem cells. Nevertheless, it has been difficult to show consistent and clinically meaningful improvement using bone marrow cell preparations above what has been achieved with microfracture. Consequently, microfracture continues to be the simplest and most commonly used method to enhance repair of focal articular cartilage defects. Emerging preclinical work in the equine model suggests a role for enhancing marrow-stimulation techniques through the use of natural scaffolds such as autologous platelet enriched fibrin as well as optimization of joint biology through localized gene therapy to support cartilage repair. In contrast to joint replacement where inert materials of known mechanical properties are used, host biology determines the relative success, failure, and durability of cartilage repair. As such, development of personalized strategies to improve the quality and durability of bone marrow cell-based articular cartilage repair represent exciting new areas of inquiry. Continued advances in stem cell biology, scaffold technologies, and methods to delineate and enhance host biology, both systemically and within the joint, hold promise for harnessing the full power of bone marrow cells to facilitate cartilage repair and regeneration.

BST-CarGel® Treatment Maintains Cartilage Repair Superiority over Microfracture at 5 Years in a Multicenter Randomized Controlled Trial

OBJECTIVE

The efficacy and safety of BST-CarGel®, a chitosan scaffold for cartilage repair was compared with microfracture alone at 1 year during a multicenter randomized controlled trial in the knee. This report was undertaken to investigate 5-year structural and clinical outcomes.

DESIGN

The international randomized controlled trial enrolled 80 patients, aged 18 to 55 years, with grade III or IV focal lesions on the femoral condyles. Patients were randomized to receive BST-CarGel® treatment or microfracture alone, and followed standardized 12-week rehabilitation. Co-primary endpoints of repair tissue quantity and quality were evaluated by 3-dimensional MRI quantification of the degree of lesion filling (%) and T2 relaxation times. Secondary endpoints were clinical benefit measured with WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) questionnaires and safety. General estimating equations were used for longitudinal statistical analysis of repeated measures.

RESULTS

Blinded MRI analysis demonstrated that BST-CarGel®-treated patients showed a significantly greater treatment effect for lesion filling (P = 0.017) over 5 years compared with microfracture alone. A significantly greater treatment effect for BST-CarGel® was also found for repair tissue T2 relaxation times (P = 0.026), which were closer to native cartilage compared to the microfracture group. BST-CarGel® and microfracture groups showed highly significant improvement at 5 years from pretreatment baseline for each WOMAC subscale (P < 0.0001), and there were no differences between the treatment groups. Safety was comparable for both groups.

CONCLUSIONS

BST-CarGel® was shown to be an effective mid-term cartilage repair treatment. At 5 years, BST-CarGel® treatment resulted in sustained and significantly superior repair tissue quantity and quality over microfracture alone. Clinical benefit following BST-CarGel® and microfracture treatment were highly significant over baseline levels.

The state of cartilage regeneration: current and future technologies

It is clear that mature human articular cartilage does not have the innate ability to regenerate. Due to this, much effort has been put forth to work on bestowing this ability. While early data focused on more basic outcomes such as percentage of defect fill, the tissue formed was a "cartilage scar" or "hyaline-like" tissue. Even with more advanced technologies, it is clear that no current procedure is able to reconstitute the native structure and function of true hyaline cartilage. As research advancement has somewhat plateaued in this regard, it is crucial that future work focuses on a multifactorial approach, treating the joint as an organ system. The purpose of this review is to update readers on the most recent literature and controversies surrounding articular cartilage regeneration. Specific focus will be placed on current technologies available in the USA and the basic science to support them.

One-step cartilage repair in the knee: collagen-covered microfracture and autologous bone marrow concentrate. A pilot study

BACKGROUND

Different single-stage surgical approaches are currently under evaluation to repair cartilage focal lesions. To date, only little is known on even short-term clinical follow-up and almost no knowledge exists on histological results of such treatments. The present paper aims to analyze the clinical and histological results of the collagen-covered microfracture and bone marrow concentrate (C-CMBMC) technique in the treatment of focal condylar lesions of knee articular cartilage.

METHODS

Nine patients with focal lesions of the condylar articular cartilage were consecutively treated with arthroscopic microfractures (MFX) covered with a collagen membrane immersed in autologous bone marrow concentrate (BMC) from the iliac crest. Patients were retrospectively assessed using several standardized outcome assessment tools and MRI scans. Four patients consented to undergo second look arthroscopy and biopsy harvest.

RESULTS

Every patient was arthroscopically treated for a focal condylar lesion (mean area 2.5 SD(0.4) cm(2)). All the patients (mean age 43 SD(9) years) but one experienced a significant clinical improvement from the pre-operative condition to the latest follow-up (mean 29 SD(11) months). Cartilage macroscopic assessment at 12 months revealed that all the repairs appeared almost normal. Histological analysis showed a hyaline-like cartilage repair in one lesion, a fibrocartilaginous repair in two lesions and a mixture of both in one lesion.

CONCLUSIONS

The first clinical experience with single-stage C-CMBMC for focal cartilage defects in the knee suggests that it is safe, it improves the short-term knee function and that it has the potential to recreate hyaline-like cartilage.

Interspecies comparison of subchondral bone properties important for cartilage repair

Microfracture repair tissue in young adult humans and in rabbit trochlea is frequently of higher quality than in corresponding ovine or horse models or in the rabbit medial femoral condyle (MFC). This may be related to differences in subchondral properties since repair is initiated from the bone. We tested the hypothesis that subchondral bone from rabbit trochlea and the human MFC are structurally similar. Trochlea and MFC samples from rabbit, sheep, and horse were micro-CT scanned and histoprocessed. Samples were also collected from normal and lesional areas of human MFC. The subchondral bone of the rabbit trochlea was the most similar to human MFC, where both had a relatively thin bone plate and a more porous and less dense character of subchondral bone. MFC from animals all displayed thicker bone plates, denser and less porous bone and thicker trabeculae, which may be more representative of older or osteoarthritic patients, while both sheep trochlear ridges and the horse lateral trochlea shared some structural features with human MFC. Since several cartilage repair procedures rely on subchondral bone for repair, subchondral properties should be accounted for when choosing animal models to study and test procedures that are intended for human cartilage repair.