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

Radiological properties of nano-hydroxyapatite compared to natural equine hydroxyapatite quantified using dual-energy CT and high-field MR

In equine medicine, assisted bone regeneration, including use of biomaterial substitutes like hydroxyapatite (HAP), is crucial for addressing bone defects. To follow-up on the outcome of HAP-based bone defect treatment, the advancement in quantified diagnostic imaging protocols is needed. This study aimed to quantify and compare the radiological properties of the HAP graft and natural equine bone using Magnetic Resonance (MR) and Computed Tomography (CT), both Single (SECT) and Dual Energy (DECT). SECT and DECT, allow for the differentiation of three HAP grain sizes, by progressive increase in relative density (RD). SECT, DECT, and MR enable the differentiation between natural cortical bone and synthetic HAP graft by augmentation in Effective Z and material density (MD) in HAP/Water, Calcium/Water, and Water/Calcium reconstructions, alongside the reduction in T2 relaxation time. The proposed quantification provided valuable radiological insights into the composition of HAP grafts, which may be useful in follow-up bone defect treatment.

Enhancing Cartilage Repair: Surgical Approaches, Orthobiologics, and the Promise of Exosomes

Treating cartilage damage is challenging as its ability for self-regeneration is limited. Left untreated, it can progress to osteoarthritis (OA), a joint disorder characterized by the deterioration of articular cartilage and other joint tissues. Surgical options, such as microfracture and cell/tissue transplantation, have shown promise as techniques to harness the body's endogenous regenerative capabilities to promote cartilage repair. Nonetheless, these techniques have been scrutinized due to reported inconsistencies in long-term outcomes and the tendency for the defects to regenerate as fibrocartilage instead of the smooth hyaline cartilage native to joint surfaces. Orthobiologics are medical therapies that utilize biologically derived substances to augment musculoskeletal healing. These treatments are rising in popularity because of their potential to enhance surgical standards of care. More recent developments in orthobiologics have focused on the role of exosomes in articular cartilage repair. Exosomes are nano-sized extracellular vesicles containing cargo such as proteins, lipids, and nucleic acids, and are known to facilitate intercellular communication, though their regenerative potential still needs to be fully understood. This review aims to demonstrate the advancements in cartilage regeneration, highlight surgical and biological treatment options, and discuss the recent strides in understanding the precise mechanisms of action involved.

Safety and Efficacy of Bone-Marrow Aspirate Concentrate in Hip Osteoarthritis: A Systematic Review of Current Clinical Evidence

Introduction

Hip osteoarthritis (OA) is one of the leading causes of disability and morbidity worldwide. It is estimated to affect 9.2% individuals globally with age over 45 years. Conventional treatment modalities have limitations and side-effects. To overcome these limitations, over the last decade, there has been an increased interest in the use of orthobiologics derived from autologous sources including platelet-rich plasma (PRP), bone-marrow aspirate concentrate (BMAC) and adipose tissue derived formulations. This review qualitatively presents the in-vitro, pre-clinical, clinical and on-going clinical studies exploring the safety and efficacy of BMAC for management of hip OA.

Materials and methods

The electronic database search was done through PubMed, Embase, Web of Science, Scopus, ProQuest and Google Scholar till February 2024. The search terms used were "osteoarthritis" OR "hip osteoarthritis" OR "orthobiologics" OR "efficacy or use of orthobiologic treatment" OR "bone-marrow concentrate" OR "bone-marrow aspirate concentrate", AND "BMAC". The inclusion criteria were clinical studies of any level of evidence written in the English language, published till February 2024, evaluating the safety and efficacy of intra-articular administration of BMAC for the management of hip OA.

Results

A total of 5 studies were included in this review for qualitative data synthesis. The total number of patients who participated in the study was 182, ranging from 4 to 112 in a single study. No adverse events were reported throughout the duration of the study. In addition, intra-articular administration of BMAC led to reduced pain, and improved function and overall quality of life (QoL).

Conclusion

The results from this review demonstrated that administration of BMAC is safe and potentially efficacious in terms of reducing pain, improving function and overall QoL of patients with hip OA in short- and mid-term average follow-up based on the included studies. Nonetheless, more adequately powered, multi-center, prospective, double-blind, non-randomized and randomized controlled trials with long-term follow-up are warranted to establish long-term safety and efficacy of BMAC for management of hip OA and justify its routine clinical use.

Synergistic Effects of Icariin and Extracellular Vesicles Derived from Rabbit Synovial Membrane-Derived Mesenchymal Stem Cells on Osteochondral Repair via the Wnt/β-Catenin Pathway

Objectives

Osteochondral defects (OCDs) are localized areas of damaged cartilage and underlying subchondral bone that can produce pain and seriously impair joint function. Literature reports indicated that icariin (ICA) has the effect of promoting cartilage repair. However, its mechanism remains unclear. Here, we explored the effects of icariin and extracellular vesicles (EVs) from rabbit synovial-derived mesenchymal stem cells (rSMSCs) on repairing of OCDs.

Materials and Methods

Rabbit primary genicular chondrocytes (rPGCs), knee skeletal muscle cells (rSMCKs), and rSMSCs, and extracellular vesicles derived from the latter two cells (rSMCK-EVs and rSMSC-EVs) were isolated and identified. The rPGCs were stimulated with ICA, rSMSC-EVs either separately or in combination. The rSMCK-EVs were used as a control. After stimulation, chondrogenic-related markers were analyzed by quantitative RT-PCR and western blotting. Cell proliferation was determined by the CCK-8 assay. The preventative effects of ICA and SMSC-EVs in vivo were determined by H&E and toluidine blue staining. Immunohistochemical analyses were performed to evaluate the levels of COL2A1 and β-catenin in vivo. Results. In vitro, the proliferation of rPGCs was markedly increased by ICA treatment in a dose-dependent manner. When compared with ICA or rSMSC-EVs treatment alone, combined treatment with ICA and SMSC-EVs produced stronger stimulative effects on cell proliferation. Moreover, combined treatment with ICA and rSMSC-EVs promoted the expression of chondrogenic-related gene, including COL2A1, SOX-9, and RUNX2, which may be via the activation of the Wnt/β-catenin pathway. In vivo, combined treatment with rSMSC-EVs and ICA promoted cartilage repair in joint bone defects. Results also showed that ICA or rSMSC-EVs both promoted the COL2A1 and β-catenin protein accumulation in articular cartilage, and that was further enhanced by combined treatment with rSMSC-EVs and ICA.

Conclusion

Our findings highlight the promising potential of using combined treatment with ICA and rSMSC-EVs for promoting osteochondral repair.

Enhanced Bone Marrow Aspirate Concentrate (BMAC) Preparation Strategy in the Management of Chondromalacia Patella: A Case Report

Chondromalacia patellae (CMP) is a widespread cause of patellofemoral pain syndrome (PFPS), which manifests as anterior knee pain and functional limitations. Current treatments frequently fail to give long-term relief, necessitating the exploration of new therapeutic techniques. Recent research has demonstrated the efficacy of Bone Marrow Aspirate Concentrate (BMAC) therapy, which utilizes the regeneration characteristics of mesenchymal stem cells (MSCs) and growth factors. We present the case of a 36-year-old male patient with Grade III CMP who was resistant to conservative treatment but was successfully treated with BMAC therapy. Detailed methods for BMAC preparation, such as double centrifugation and growth factor analysis, are presented. At six and 12 weeks after therapy, the patient showed significant improvements in pain and functional results, as well as enhanced levels of growth factors and CD34+ cells in the BMAC. This study provides insights into the regeneration potential of BMAC therapy and highlights its promising role in managing chondral abnormalities. Larger clinical trials and standardization of BMAC preparation procedures are necessary for establishing its effectiveness and consistency as a standard treatment approach for CMP.

Intraarticular treatment with integrin α10β1-selected mesenchymal stem cells affects microRNA expression in experimental post-traumatic osteoarthritis in horses

Osteoarthritis (OA) remains a major cause of lameness in horses, which leads to lost days of training and early retirement. Still, the underlying pathological processes are poorly understood. MicroRNAs (miRNAs) are small non-coding RNAs that serve as regulators of many biological processes including OA. Analysis of miRNA expression in diseased joint tissues such as cartilage and synovial membrane may help to elucidate OA pathology. Since integrin α10β1-selected mesenchymal stem cell (integrin α10-MSC) have shown mitigating effect on equine OA we here investigated the effect of integrin α10-MSCs on miRNA expression. Cartilage and synovial membrane was harvested from the middle carpal joint of horses with experimentally induced, untreated OA, horses with experimentally induced OA treated with allogeneic adipose-derived MSCs selected for the marker integrin α10-MSCs, and from healthy control joints. miRNA expression in cartilage and synovial membrane was established by quantifying 70 pre-determined miRNAs by qPCR. Differential expression of the miRNAs was evaluated by comparing untreated OA and control, untreated OA and MSC-treated OA, and joints with high and low pathology score. A total of 60 miRNAs were successfully quantified in the cartilage samples and 55 miRNAs were quantified in the synovial membrane samples. In cartilage, miR-146a, miR-150 and miR-409 had significantly higher expression in untreated OA joints than in control joints. Expression of miR-125a-3p, miR-150, miR-200c, and miR-499-5p was significantly reduced in cartilage from MSC-treated OA joints compared to the untreated OA joints. Expression of miR-139-5p, miR-150, miR-182-5p, miR-200a, miR-378, miR-409-3p, and miR-7177b in articular cartilage reflected pathology score. Several of these miRNAs are known from research in human patients with OA and from murine OA models. Our study shows that these miRNAs are also differentially expressed in experimental equine OA, and that expression depends on OA severity. Moreover, MSC treatment, which resulted in less severe OA, also affected miRNA expression in cartilage.

The Mechanism of Pyroptosis and Its Application Prospect in Diabetic Wound Healing

Pyroptosis defines a form of pro-inflammatory-dependent programmed cell death triggered by gasdermin proteins, which creates cytoplasmic pores and promotes the activation and accumulation of immune cells by releasing several pro-inflammatory mediators and immunogenic substances upon cell rupture. Pyroptosis comprises canonical (mediated by Caspase-1) and non-canonical (mediated by Caspase-4/5/11) molecular signaling pathways. Numerous studies have explored the contributory roles of inflammasome and pyroptosis in the progression of multiple pathological conditions such as tumors, nerve injury, inflammatory diseases and metabolic disorders. Accumulating evidence indicates that the activation of the NOD-like receptor thermal protein domain associated protein 3 (NLRP3) inflammasome results in the activation of pyroptosis and inflammation. Current evidence suggests that pyroptosis-dependent cell death plays a progressive role in the development of diabetic complications including diabetic wound healing (DWH) and diabetic foot ulcers (DFUs). This review presents a brief overview of the molecular mechanisms underlying pyroptosis and addresses the current research on pyroptosis-dependent signaling pathways in the context of DWH. In this review, we also present some prospective therapeutic compounds/agents that can target pyroptotic signaling pathways, which may serve as new strategies for the effective treatment and management of diabetic wounds.

Atelocollagen Scaffold Enhances Cartilage Regeneration in Osteochondral Defects: A Study in Rabbits

BACKGROUND

To enhance articular cartilage healing, microfractures (Mfx) and bone marrow aspirate concentrate (BMAC) are commonly used, and some form of scaffold is often used together to increase its efficacy. Herein, we compared the efficacy of atelocollagen scaffold to that of collagen scaffold when used with Mfx or BMAC on osteochondral defect of animal.

METHODS

This experiment was designed in two stages, and therapeutic effects of Mfx and BMAC were respectively evaluated when used with atelocollagen or collagen scaffold. Femoral condyle defects were artificially created in male New Zealand White rabbits, and in each stage, 12 rabbits were randomly allocated into three treatment groups: test group with additional atelocollagen scaffold, the positive control group with collagen scaffold, and the negative control group. Then, for 12 weeks, macroscopic and histological evaluations were performed.

RESULTS

At 12 weeks, defects in the test group were fully regenerated with normal cartilage-like tissue, and were well integrated with the surrounding cartilage at both stages experiment, whereas defects in the control groups were not fully filled with regenerated tissue, and the tissue appeared as fibrous tissue. Histologically, the regenerated tissue in the test group showed a statistically significant improvement compared to the positive and negative control groups, achieving a similar structure as normal articular cartilage.

CONCLUSION

The results showed that implantation of the atelocollagen scaffold enhanced cartilage regeneration following osteochondral defects in rabbits. This suggests that the atelocollagen scaffold can be used with Mfx or BMAC for effective regeneration of osteochondral defects.

Introduction to Equine Biologic and Regenerative Therapies

Regenerative medicine is defined as the process of replacing or regenerating cells, tissues, or organs to restore or establish normal function. The use of regenerative medicine in equine practice to treat injured musculoskeletal tissues with limited capacity for intrinsic healing is growing. This article provides the practitioner with a brief and basic overview of the regenerative products currently used in equine practice.

Equine Bone Marrow Aspirate Concentrate

Bone marrow concentrate is generated by centrifugation of bone marrow aspirate. It contains mesenchymal stromal cells, anabolic chemokines/cytokines, and supraphysiological concentrations of interleukin-1 receptor antagonist protein (IL-1RA). It is an effective treatment for osteoarthritis or desmitis, or as an adjunct in surgery to enhance bone or cartilage repair.

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

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

Mesenchymal Stem Cells Isolated from Equine Hair Follicles Using a Method of Air-Liquid Interface

Equine mesenchymal stem cells (MSC) of various origins have been identified in horses, including MSCs from the bone marrow and adipose tissue. However, these stem cell sources are highly invasive in sampling, which thereby limits their clinical application in equine veterinary medicine. This study presents a novel method using an air-liquid interface to isolate stem cells from the hair follicle outer root sheath of the equine forehead skin. These stem cells cultured herewith showed high proliferation and asumed MSC phenotype by expressing MSC positive biomarkers (CD29, CD44 CD90) while not expressing negative markers (CD14, CD34 and CD45). They were capable of differentiating towards chondrogenic, osteogenic and adipogenic lineages, which was comparable with MSCs from adipose tissue. Due to their proliferative phenotype in vitro, MSC-like profile and differentiation capacities, we named them equine mesenchymal stem cells from the hair follicle outer root sheath (eMSCORS). eMSCORS present a promising alternative stem cell source for the equine veterinary medicine.

Novel Osteochondral Biotemplate Improves Long-term Cartilage Repair Compared With Microfracture in an Ovine Model

BACKGROUND

Current cartilage repair therapies do not re-create the complex mechanical interface between cartilage and bone, which is critical for long-term repair durability. New biomaterial designs that include hard tissue-soft tissue interface structures offer promise to improve clinical outcomes.

PURPOSE/HYPOTHESIS

The purpose of this study was to evaluate the efficacy and safety of a naturally derived osteochondral biotemplate with a novel contiguous hard tissue-soft tissue interface in an ovine model as a regenerative solution for articular cartilage defects. It was hypothesized that the osteochondral biotemplate would produce structurally superior repair tissue compared with microfracture over a 13-month period.

STUDY DESIGN

Controlled laboratory study.

METHODS

Osteochondral biotemplates were manufactured from porcine cancellous bone. Skeletally mature sheep (N = 30) were randomly allocated to 3 groups: early healing stage (euthanasia at 4 months), 6-month treatment, and 13-month treatment. In the early healing stage group, an 8 mm-diameter by 5 mm-deep osteochondral defect was created on the medial femoral condyle and treated at the time of iatrogenic injury with an osteochondral biotemplate. The contralateral limb received the same treatment 2 months later. In the 6- and 13-month treatment groups, 1 limb received the same osteochondral procedure as the early healing stage group. In the contralateral limb, an 8 mm-diameter, full-thickness cartilage defect (1-2 mm deep) was created and treated with microfracture. Cartilage repair and integration were quantitatively and qualitatively assessed with gross inspection, histological evaluation, and magnetic resonance imaging (MRI). Wilcoxon signed-rank and McNemar tests were used to compare the treatments.

RESULTS

At 6 and 13 months after treatment, the biotemplate was not present histologically. At 13 months, the biotemplate treatment demonstrated statistically higher histological scores than microfracture for integration with surrounding cartilage (biotemplate: 74 ± 31; microfracture: 28 ± 39; P = .03), type 2 collagen (biotemplate: 72 ± 33; microfracture: 40 ± 38; P = .02), total cartilage (biotemplate: 71 ± 9; microfracture: 59 ± 9; P = .01), and total integration (biotemplate: 85 ± 15; microfracture: 66 ± 20; P = .04). The osteochondral biotemplate treatment produced a notable transient nonneutrophilic inflammatory response that appeared to approach resolution at 13 months. MRI results were not statistically different between the 2 treatments.

CONCLUSION

Even with the inflammatory response, after 13 months, the osteochondral biotemplate outperformed microfracture in cartilage regeneration and demonstrated superiority in integration between the repair tissue and host tissue as well as integration between the newly formed cartilage and the underlying bone.

CLINICAL RELEVANCE

This work has demonstrated the clinical potential of a novel biomaterial template to regenerate the complex mechanical interface between cartilage and the subchondral bone.

Pro-Inflammatory Cytokine Priming and Purification Method Modulate the Impact of Exosomes Derived from Equine Bone Marrow Mesenchymal Stromal Cells on Equine Articular Chondrocytes

Osteoarthritis (OA) is a widespread osteoarticular pathology characterized by progressive hyaline cartilage degradation, exposing horses to impaired well-being, premature career termination, alongside substantial financial losses for horse owners. Among the new therapeutic strategies for OA, using mesenchymal stromal cell (MSC)-derived exosomes (MSC-exos) appears to be a promising option for conveying MSC therapeutic potential, yet avoiding the limitations inherent to cell therapy. Here, we first purified and characterized exosomes from MSCs by membrane affinity capture (MAC) and size-exclusion chromatography (SEC). We showed that intact MSC-exos are indeed internalized by equine articular chondrocytes (eACs), and then evaluated their functionality on cartilaginous organoids. Compared to SEC, mRNA and protein expression profiles revealed that MAC-exos induced a greater improvement of eAC-neosynthesized hyaline-like matrix by modulating collagen levels, increasing PCNA, and decreasing Htra1 synthesis. However, because the MAC elution buffer induced unexpected effects on eACs, an ultrafiltration step was included to the isolation protocol. Finally, exosomes from MSCs primed with equine pro-inflammatory cytokines (IL-1β, TNF-α, or IFN-γ) further improved the eAC hyaline-like phenotype, particularly IL-1β and TNF-α. Altogether, these findings indicate the importance of the exosome purification method and further demonstrate the potential of pro-inflammatory priming in the enhancement of the therapeutic value of MSC-exos for equine OA treatment.

Osteochondral Lesions of the Talus: The Questions We Would Like Answered

Osteochondral lesions of the talus is common pathology that foot and ankle surgeons evaluate and treat. There is a variety of treatment modalities at the surgeon's disposal to repair these lesions, which include both open and arthroscopic surgical techniques. Although both open and arthroscopic techniques have a good success rate, there are still many debates and questions that surround this pathology. The goal of this article is to discuss some of the common questions that we ask ourselves and other surgeons.

Treatment of talus osteochondral defects with arthroscopy debridement and bone marrow concentrate: a 6-month follow-up case report study

Talus osteochondral defects are a common cause of ankle pain and disability, and require prompt and effective treatment to prevent further damage and improve function. While surgical interventions, such as arthroscopy debridement and bone marrow concentrate therapy, have been used separately to treat these injuries, their combination may offer synergistic benefits. A 28-year-old male patient presented with a history of ankle pain and difficulty with weight-bearing activities. Post-operatively, the patient reported significant improvement in pain and function.

Advances in Cartilage Repair

Osteochondral lesions of the ankle joint are typically associated with a traumatic etiology and present with ankle pain and swelling. Conservative management yields unsatisfactory results because of the poor healing capacity of the articular cartilage. Smaller lesions (<100 mm² or <10 mm) can be treated with less invasive procedures such as arthroscopic debridement, anterograde drilling, scaffold-based therapies, and augmentation with biological adjuvants. For patients with large lesions (>100 mm² or >10 mm), cystic lesions, uncontained lesions, or patients who have failed prior bone marrow stimulation, management with autologous osteochondral transplantation is indicated.

Patients With Knee Osteoarthritis Who Receive Platelet-Rich Plasma or Bone-Marrow Aspirate Concentrate Injections Have Better Outcomes Than Patients Who Receive Hyaluronic Acid: Systematic Review and Meta-analysis

PURPOSE

To systematically review the literature in order to compare the efficacy and safety of platelet-rich plasma (PRP), bone marrow aspirate concentrate (BMAC), and hyaluronic acid (HA) injections for the treatment of knee osteoarthritis (OA).

METHODS

A systematic review was performed by searching PubMed, the Cochrane Library, and Embase to identify Level I studies that compared the clinical efficacy of at least 2 of the following 3 injection therapies: PRP, BMAC, and HA for knee OA. The search phrase used was knee AND osteoarthritis AND randomized AND ("platelet rich plasma" OR "bone marrow aspirate" OR "hyaluronic acid"). Patients were primarily assessed based on patient-reported outcome scores (PROs) including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), visual analog scale (VAS) for pain, and Subjective International Knee Documentation Committee (IKDC) score.

RESULTS

Twenty-seven studies (all Level I) met inclusion criteria, including 1,042 patients undergoing intra-articular injection(s) with PRP (mean age 57.7 years, mean follow-up 13.5 months), 226 patients with BMAC (mean age 57.0 years, mean follow-up 17.5 months), and 1,128 patients with HA (mean age 59.0 years, mean follow-up 14.4 months). Non-network meta-analyses demonstrated significantly better post-injection WOMAC (p < 0.001), VAS (p < 0.01), and Subjective IKDC scores (p < 0.001) in PRP patients when compared to HA patients. Similarly, network meta-analyses demonstrated significantly better post-injection WOMAC (p < 0.001), VAS (p = 0.03), and Subjective IKDC (p < 0.001) scores in BMAC patients when compared to HA patients. There were no significant differences in post-injection outcome scores when comparing PRP to BMAC.

CONCLUSION

Patients undergoing treatment for knee OA with PRP or BMAC can be expected to experience improved clinical outcomes when compared to HA patients.

LEVEL OF EVIDENCE

I, Meta-Analysis of Level I studies.

Equine osteoarthritis: Strategies to enhance mesenchymal stromal cell-based acellular therapies

Osteoarthritis (OA) is a degenerative disease that eventually leads to the complete degradation of articular cartilage. Articular cartilage has limited intrinsic capacity for self-repair and, to date, there is no curative treatment for OA. Humans and horses have a similar articular cartilage and OA etiology. Thus, in the context of a One Health approach, progress in the treatment of equine OA can help improve horse health and can also constitute preclinical studies for human medicine. Furthermore, equine OA affects horse welfare and leads to significant financial losses in the equine industry. In the last few years, the immunomodulatory and cartilage regenerative potentials of mesenchymal stromal cells (MSCs) have been demonstrated, but have also raised several concerns. However, most of MSC therapeutic properties are contained in their secretome, particularly in their extracellular vesicles (EVs), a promising avenue for acellular therapy. From tissue origin to in vitro culture methods, various aspects must be taken into consideration to optimize MSC secretome potential for OA treatment. Immunomodulatory and regenerative properties of MSCs can also be enhanced by recreating a pro-inflammatory environment to mimic an in vivo pathological setting, but more unusual methods also deserve to be investigated. Altogether, these strategies hold substantial potential for the development of MSC secretome-based therapies suitable for OA management. The aim of this mini review is to survey the most recent advances on MSC secretome research with regard to equine OA.

Bone Marrow-Derived Fibrin Clots Stimulate Healing of a Meniscal Defect in a Rabbit Model

PURPOSE

To determine the in vivo effectiveness of bone marrow aspirate-derived (BMA) fibrin clots for avascular meniscal defect healing in a rabbit model.

METHODS

In 42 Japanese white rabbits, a 2.0-mm cylindrical defect was introduced into the avascular zone of the anterior part of the medial meniscus in the bilateral knees. The rabbits were grouped according to implantation of a BMA fibrin clot (BMA group) or a peripheral blood (PB)-derived clot (PB group) into the defect and nonimplantation (control group). Macroscopic and histological assessments were performed using a scoring system at 4 and 12 weeks after surgery. At 12 weeks after surgery, compressive stress was analyzed biomechanically.

RESULTS

The meniscal score in the BMA group (12.1) was greater than that in the PB group (5.5; P = .031) and control group (4.4; P = .013) at 4 weeks. The meniscal score in the BMA group (13.1) was greater than that in the control group (6.4; BMA = 13.1; P = .0046) at 12 weeks. In the biomechanical analysis, the BMA group demonstrated significantly higher compressive strength than the PB group (6.6 MPa) (BMA = 15.4 MPa; P = .0201) and control group (3.6 MPa; BMA = 15.4 MPa; P = .007).

CONCLUSIONS

Implantation of BMA fibrin clots into the meniscal defect of the avascular zone in a rabbit model improved the meniscal score at 4 weeks and strengthened the reparative meniscal tissue at 12 weeks compared with the implantation of PB fibrin clots.

CLINICAL RELEVANCE

Healing in the avascular zone of the meniscus can be problematic. Approaches to improving this healing response have had variable results. This study provides additional information that may help improve the outcomes in patients with these injuries.

The Potential of Using an Autogenous Tendon Graft by Injecting Bone Marrow Aspirate in a Rabbit Meniscectomy Model

Bone marrow aspirate (BMA) is an excellent source of cells and growth factors and has been used successfully for bone, cartilage, and soft-tissue healing. This study aimed to investigate the histological and biomechanical properties of autogenous tendon graft by injecting BMA and its protective effect against degenerative changes in a rabbit model of meniscal defects. Adult white rabbits were divided into untreated, tendon, and tendon + BMA groups, and meniscal defects were created in the knees. The tendon graft and articular cartilage status were evaluated by macroscopic and histological analysis at 4, 12, and 24 weeks postoperatively among the three groups. The tendon graft in the tendon and tendon + BMA groups were used for biomechanical evaluation at 4, 12, and 24 weeks postoperatively. The meniscal covering ratio in the tendon + BMA group was better than that in the tendon and untreated groups at 12 and 24 weeks postoperatively. The matrix around the central portion of cells in the tendon + BMA group was positively stained by safranin O and toluidine blue staining with metachromasia at 24 weeks. The histological score of the tendon graft in the tendon + BMA group was significantly higher than that in the untreated and tendon groups at 12 and 24 weeks postoperatively. In the tendon + BMA group, cartilage erosion was not shown at 4 weeks, developed slowly, and was better preserved at 12 and 24 weeks compared to the untreated and tendon groups. Histological scores for the articular cartilage were significantly better in the tendon + BMA group at 24 weeks. The compressive stress on the tendon graft in the tendon + BMA group was significantly higher than that in the tendon group at 12 weeks postoperatively. Transplantation of autogenous tendon grafts by injecting BMA improved the histologic score of the regenerated meniscal tissue and was more effective than the tendon and untreated group for preventing cartilage degeneration in a rabbit model of massive meniscal defects.

Augmenting Osteochondral Autograft Transplantation and Bone Marrow Aspirate Concentrate with Particulate Cartilage Extracellular Matrix Is Associated With Improved Outcomes

BACKGROUND

Osteochondral autograft transplant (OAT) is often used to treat large osteochondral lesions of the talus and is generally associated with good outcomes. The addition of adjuncts such as cartilage extracellular matrix with bone marrow aspirate concentrate (ECM-BMAC) may further improve the OAT procedure but have not been thoroughly studied. We hypothesized that the placement of ECM-BMAC around the OAT graft would improve radiographic and patient-reported outcomes following OAT.

METHODS

Patients who received OAT, with ECM-BMAC or BMAC alone, were screened and their charts were reviewed. For patients who did receive ECM-BMAC, the mixture was spread around the edges of the OAT plug and into any surrounding areas of cartilage damage. Survey and radiographic data were collected. Average follow-up in both groups was over 2 years. Magnetic resonance imaging scans were scored using the Magnetic Resonance Observation of Cartilage Tissue (MOCART) system. Outcomes were compared statistically between groups.

RESULTS

Patients treated with ECM-BMAC (n = 34) demonstrated significantly greater improvement of scores in the FAOS categories Symptoms (17 vs -3; P = .02) and Sports Activities (40 vs 7; P = .02), and the MOCART category Subchondral Lamina (P = .008) compared to those treated with BMAC alone (n = 30). They also experienced significantly lower rates of postoperative cysts (53% vs 18%, P = .04) and edema (94% vs 59%, P = .02).

CONCLUSION

The addition of ECM-BMAC to OAT was associated with improved imaging and clinical outcomes compared to OAT with BMAC alone.

Differentiation of Equine Mesenchymal Stem Cells into Cells of Osteochondral Lineage: Potential for Osteochondral Tissue Engineering

Damage to the hyaline cartilage of the joint surface and osteochondral fractures are key factors leading to the development of osteoarthritis in racehorses, representing a significant cause of racehorse retirement. To tissue-engineer an osteochondral unit that is suitable for joint repair, incorporation of a zone of calcified cartilage should be considered so as to mimic its in vivo counterpart. To date, equine mesenchymal stem cells (eMSCs) have been reported to have multilineage differentiation potential. Yet the generation of a zone of calcified cartilage using eMSCs has not been reported. This work is an initial attempt to generate a zone of calcified cartilage using eMSCs as the single source of cells and collagen as the scaffolding material. Main advantages of using eMSCs over equine deep zone chondrocytes for the generation of a zone of calcified cartilage include no donor site morbidity and their ease of expansion in culture. Initially, we fabricated cartilage-like tissues and bone-like tissues in vitro by differentiating eMSCs towards chondrogenic and osteogenic lineages for 21 days, respectively. We then aggregated the cartilage-like and bone-like tissues together with a layer of undifferentiated eMSCs-collagen gel in between to generate a 3-layer osteochondral unit. A zone of calcified cartilage was found between the cartilage-like and bone-like layers after a 14-day culture in chondrogenic differentiation medium. These results provide a solution towards tissue engineering of equine osteochondral units with interfacial zone without using chondrocytes harvested from the deep zone of healthy articular cartilage, and contribute to the future development of osteochondral tissue engineering strategies for human cartilage injuries in the long run.

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

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

Clinical and Magnetic Resonance Imaging Outcomes After Microfracture Treatment With and Without Augmentation for Focal Chondral Lesions in the Knee: A Systematic Review and Meta-analysis

BACKGROUND

Focal cartilage lesions represent a common source of knee pain and disability, with the potential for the development and progression of osteoarthritis. Currently, microfracture (MFx) represents the most utilized first-line surgical treatment for small, focal chondral lesions. Recent investigations have examined methods of overcoming the limitations of MFx utilizing various augmentation techniques.

PURPOSE

To perform a systematic review and meta-analysis evaluating clinical and radiographic outcomes in patients undergoing isolated MFx versus MFx augmented with orthobiologics or scaffolds for focal chondral defects of the knee.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

A systematic review was performed to identify studies evaluating outcomes and adverse events in patients undergoing isolated MFx versus augmented MFx for focal chondral defects in the knee from 1945 to June 1, 2021. Data were extracted from each article that met the inclusion/exclusion criteria. Meta-analyses were performed for all outcomes reported in a minimum of 3 studies.

RESULTS

A total of 14 studies were identified, utilizing 7 different types of injectable augmentation regimens and 5 different scaffolding regimens. Across the 14 studies, a total of 744 patients were included. The mean patient age was 46.8 years (range, 34-58 years), and 58.3% (n = 434/744) of patients were women. The mean final follow-up time was 26.7 months (range, 12-60 months). The mean chondral defect size ranged from 1.3 to 4.8 cm². A post hoc analysis comparing mean improvement in postoperative outcomes scores compared with preoperative values found no significant differences in the improvement in the visual analog scale (VAS), International Knee Documentation Committee (IKDC), or Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores between patients undergoing isolated MFx and those undergoing MFx + augmentation. Patients undergoing MFx + augmentation reported significantly greater improvements in the Lysholm score and postoperative MOCART (magnetic resonance observation of cartilage repair tissue) scores compared with the isolated MFx group.

CONCLUSION

Patients undergoing combined MFx + augmentation reported significant improvements in mean Lysholm and MOCART scores, without significant improvements in VAS, IKDC, or WOMAC scores when compared with patients undergoing isolated MFx.

Limited evidence for biological treatment measures for cartilage and tendon injuries of the shoulder

PURPOSE

To critically review the available literature on the usage of biologics to treat cartilage and tendon injuries of the shoulder.

METHODS

Four different databases were searched in January 2020 for studies reporting data on bone marrow stimulation, autologous chondrocyte implantation, platelet-rich plasma, autologous concentrated serum, and bone marrow aspirate concentrate for the treatment of cartilage and/or tendon injuries of the shoulder. Prospective, retrospective, cohort and case-control studies as well as case series, systematic reviews and laboratory studies (involving human tissue) were included. Cadaveric or animal studies were excluded. Findings were summarized and an expert opinion on trends was provided.

RESULTS

Although there is limited literature available on biologics in cartilage lesions of the shoulder, the advancement from micro- to nanofracture, that is well established for the treatment of cartilage lesions in the knee, may be the next step in the treatment of shoulder lesions as well. The high rate of failure and therefore the complexity of tendon healing following rotator cuff repair has led to a rising interest in biologic augmentation such as platelet-rich plasma and stem cells to enhance tendon-bone-healing and to decrease the prevalence of failure. Despite the increase in publications, there exists a huge heterogeneity of content, quality, and quantity of among studies and their processing methods reporting the use of platelet-rich plasma in rotator cuff repair.

CONCLUSION

Conclusions from individual studies cannot be generalized. Currently, no evidence supports that platelet-rich plasma provides clinical benefits in rotator cuff repair. Similar is reported for microfracture in rotator cuff repair, however, despite no clinical benefits, microfracture has shown to reduce the appearance of structural failures. Although some evidence exists for the use of stem cells form bone marrow aspirate concentrate, results from large case series are still lacking.

LEVEL OF EVIDENCE

Level V.

Osteochondral Lesions of the Ankle Treated with Bone Marrow Concentrate with Hyaluronan and Fibrin: A Single-Centre Study

Osteochondral defects of the ankle (OCD) are being increasingly identified as a clinically significant consequence of injury to the ankle, with the potential to lead to osteoarthritis if left untreated. The aim of this retrospective cohort study was to evaluate a single-stage treatment of OCD, based on bone marrow aspirate (BMA) centrifuged to produce bone marrow concentrate (BMC). In a dual syringe, the concentrate was mixed with thrombin in one syringe, whereas hyaluronan and fibrinogen were mixed in a second syringe. The two mixtures were then injected and combined into the prepared defect. Clinical outcome and quality of life scores (MOXFQ and EQ-5D) were collected at baseline and yearly thereafter. Multilevel models were used to analyse the pattern of scores over time. Ninety-four patients were treated between 2015 and 2020. The means of each of the three components of the MOXFQ significantly improved between baseline and 1 year (p < 0.001 for each component), with no further change from year 1 to year 3. The EQ-5D index also improved significantly from baseline to 1 year, with no evidence for further change. Our results strongly indicate that this BMC treatment is safe for, and well tolerated by, patients with OCD of the ankle as both primary treatment and those who have failed primary treatment. This technique provides a safe, efficacious alternative to currently employed cartilage repair techniques, with favourable outcomes and a low complication rate at 36 months.

Biochemical Characteristics and Clinical Result of Bone Marrow-Derived Fibrin Clot for Repair of Isolated Meniscal Injury in the Avascular Zone

PURPOSE

To characterize bone marrow aspirate-derived fibrin clot (BMA clot) and evaluate the clinical result of meniscal repair with a BMA clot for isolated meniscal injury in the avascular zone.

METHODS

Blood counts of total leukocytes, platelets, and concentrations of basic fibroblast growth factor (bFGF), transforming growth factor β (TGF-β), and stromal cell-derived factor 1 (SDF-1) were analyzed with BMA, peripheral blood (PB), BMA clot, and PB clot from 5 patients treated for meniscal repair. In addition, a retrospective analysis of 30 patients with isolated avascular meniscal injuries who underwent repair with a BMA clot was performed to assess rate failure. Avascular meniscal injury was identified as horizontal tear, radial tear, and flap tear. Clinical failure was defined as the presence of 1 or more of Barrett's criteria. Anatomic failure was defined as the existence of equivalent signal intensity to intra-articular fluid along the repair area on follow-up magnetic resonance imaging (MRI). Patients' demographic and clinical data were compared between the overall failure group and the success group.

RESULTS

The bFGF, TGF-β, and SDF-1 levels of BMA clots were more highly concentrated compared with PB clots. The Lysholm scores and meniscal status evaluated by MRI were significantly improved from preoperatively to postoperatively (both P < .001). The Kellgren-Lawrence grading of knee radiographs did not significantly differ pre- and postoperatively (P = .140). Rates of clinical failure, anatomic failure, and retear were 10%, 6.7%, and 3.3%, respectively. The demographic characteristics and surgical and postoperative status did not significantly differ between the overall failure group and the success group.

CONCLUSIONS

BMA clots had increased levels of cytokines compared to PB clots. The retrospective analysis revealed that the rates of clinical failure and anatomic failure after meniscal repair with a BMA clot for isolated avascular meniscal injury were 10% and 6.7%, respectively.

LEVEL OF EVIDENCE

Level IV, case series.

Functional Outcomes of Arthroscopic Acetabular Labral Repair with and without Bone Marrow Aspirate Concentrate

BACKGROUND

Osteoarthritis (OA) of the hip is a debilitating condition associated with inferior outcomes in patients undergoing hip arthroscopy. To provide symptom relief and improve outcomes in these patients, bone marrow aspirate concentrate (BMAC) has been applied as an adjuvant therapy with the hope of halting progression of cartilage damage. The current study examined the clinical efficacy of BMAC application in patients undergoing arthroscopic acetabular labral repair by comparing patient-reported outcome measures (PROMs) between groups with and without BMAC application.

METHODS

Patients who received BMAC during arthroscopic acetabular labral repair from December 2016 to June 2019 were compared with a control cohort that underwent the same procedure but did not receive BMAC from November 2013 to November 2016. Patients in both cohorts were asked to prospectively complete PROMs prior to surgery and at 3, 6, 12, and 24-month follow-up intervals; those who completed the PROMs at enrollment and the 12-month follow-up were included in the study. An a priori subgroup analysis was performed among patients with moderate cartilage damage (Outerbridge grade 2 or 3). The analyses were adjusted for any differences in baseline factors between groups.

RESULTS

Sixty-two patients with BMAC application were compared with 62 control patients without BMAC application. When compared with the no-BMAC cohort, the BMAC cohort did not report significantly different mean International Hip Outcome Tool-33 (iHOT-33) scores at any postoperative time point. However, when patients with moderate cartilage damage were compared across groups, the BMAC cohort reported significantly greater mean (95% confidence interval) scores than the no-BMAC cohort at the 12-month (78.6 [72.4 to 84.8] versus 69.2 [63.3 to 75.2]; p = 0.035) and 24-month (82.5 [73.4 to 91.6] versus 69.5 [62.1 to 76.8]; p = 0.030) follow-up. Similarly, these patients reported greater score improvements at 12 months (37.3 [30.3 to 44.3] versus 25.4 [18.7 to 32.0]; p = 0.017) and 24 months (39.6 [30.4 to 48.7] versus 26.4 [19.1 to 33.8]; p = 0.029).

CONCLUSIONS

Patients with moderate cartilage injury undergoing arthroscopic acetabular labral repair with BMAC application reported significantly greater functional improvements when compared with similar patients without BMAC application.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Outcomes of Autologous Osteochondral Transplantation With and Without Extracellular Matrix Cartilage Allograft Augmentation for Osteochondral Lesions of the Talus

BACKGROUND

Autologous osteochondral transplantation (AOT) using a cylindrical graft in the treatment of osteochondral lesions of the talus (OLTs) is typically indicated for patients with larger lesions. However, with lesions that are irregular in shape, the AOT graft may not completely replace the lesion. For these lesions, we utilize extracellular matrix cartilage allograft (EMCA) augmentation in AOT to act as a physiologic grout at the host-graft interface.

PURPOSE

To determine if the combination of EMCA with concentrated bone marrow aspirate (CBMA) would improve integration of the host-graft interface and subsequently reduce postoperative cyst formation after AOT. It was also hypothesized that EMCA in conjunction with CBMA would demonstrate improved MOCART (magnetic resonance observation of cartilage repair tissue) scores and functional outcome scores at a minimum 2 years after surgery.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective analysis was performed comparing patients treated with AOT/CBMA alone and AOT with CBMA/EMCA. Clinical outcomes were evaluated with the Foot and Ankle Outcome Score. Magnetic resonance imaging appearance was evaluated with the use of the MOCART (magnetic resonance observation of cartilage repair tissue) score. Cyst formation was also evaluated on postoperative magnetic resonance imaging.

RESULTS

A total of 26 patients were included in the AOT + CBMA/EMCA group (10 male, 16 female), and 34 patients were included in the AOT/CBMA group (17 male, 17 female). The mean Foot and Ankle Outcome Score significantly improved in both groups (P < .001) across all subscales (symptoms, pain, activities of daily living, sports activities, and quality of life), but there was no significant difference between groups at final follow-up. There was no significant difference in mean MOCART scores between the groups (P = .118). In the AOT/CBMA group, 3 patients (8.8%) complained of knee pain, and 1 (2.9%) required additional surgery (hardware removal). In the AOT + CBMA/EMCA group, 2 patients (7.7%) complained of knee pain, and 6 patients (23%) required additional surgery (3 hardware removals and 3 arthroscopic debridements of scar tissue in the ankle).

CONCLUSION

We found that while EMCA with CBMA has benefit in regeneration and repair of OLT treated with bone marrow stimulation, there appears to be little benefit of EMCA over CBMA alone as a physiologic grout at the graft-host interface in OLT treated with AOT.

Comparison of All Arthroscopic Implantation of Chitosan-Based Liquid Scaffold and Hyaluronan-Based Soft Scaffold in the Treatment of Condylar Osteochondral Lesions in the Knee

Cell-free scaffolds used in cartilage regeneration are produced from different materials. The aim of this study is to compare the clinical and radiological results of two different scaffolds with hyaluronan- or chitosan-based structure used in the treatment of symptomatic condylar osteochondral lesions. The study comprises 69 patients who were operated for osteochondral lesion repair with hyaluronan- (n = 37) or chitosan-based (n = 32) scaffold. The International Knee Documentation Committee (IKDC), Lysholm Knee Scoring Scale and Visual Analog Scale (VAS) scores were collected for both groups at the preoperative and postoperative 3rd, 12th, and 24th months. Magnetic resonance imaging was performed between the 12th and 15th months postoperatively and this with magnetic resonance observation of cartilage repair tissue (MOCART) scoring were compared. Within group assessments demonstrate significant improvement in IKDC, Lysholm, and VAS scores at postoperative 3rd and 12th months. However, in both groups, IKDC, Lysholm and, VAS scores at the postoperative 24th month indicate no significant further improvement, compared with the 12th month results. There was no significant difference between the groups in terms of IKDC, Lysholm, VAS, and MOCART scores at any time period. This study shows that both scaffolds are useful in cartilage regeneration but have no clinical or radiological superiority to each other. Surgeons should select the method with which they feel comfortable. This is a level III, retrospective comparative study.

Algorithm for Treatment of Focal Cartilage Defects of the Knee: Classic and New Procedures

OBJECTIVE

To create a treatment algorithm for focal grade 3 or 4 cartilage defects of the knee using both classic and novel cartilage restoration techniques.

DESIGN

A comprehensive review of the literature was performed highlighting classic as well as novel cartilage restoration techniques supported by clinical and/or basic science research and currently being employed by orthopedic surgeons.

RESULTS

There is a high level of evidence to support the treatment of small to medium size lesions (<2-4 cm2) without subchondral bone involvement with traditional techniques such as marrow stimulation, osteochondral autograft transplant (OAT), or osteochondral allograft transplant (OCA). Newer techniques such as autologous matrix-induced chondrogenesis and bone marrow aspirate concentrate implantation have also been shown to be effective in select studies. If subchondral bone loss is present OAT or OCA should be performed. For large lesions (>4 cm2), OCA or matrix autologous chondrocyte implantation (MACI) may be performed. OCA is preferred over MACI in the setting of subchondral bone involvement while cell-based modalities such as MACI or particulated juvenile allograft cartilage are preferred in the patellofemoral joint.

CONCLUSIONS

Numerous techniques exist for the orthopedic surgeon treating focal cartilage defects of the knee. Treatment strategies should be based on lesion size, lesion location, subchondral bone involvement, and the level of evidence supporting each technique in the literature.

Biological Mechanisms for Cartilage Repair Using a BioCartilage Scaffold: Cellular Adhesion/Migration and Bioactive Proteins

Objective. BioCartilage is a desiccated, particulated cartilage allograft used for repair of focal cartilage defects. It is mixed with a biologic such as bone marrow concentrate (BMC), pressed into a contained defect, and sealed with fibrin glue. The objective of this study was to assess if BioCartilage could serve as a bioactive scaffold by affecting cellular adhesion, cellular migration, or the release interleukin-1 receptor antagonist protein (IL-1RA), and to identify its full proteomic makeup. Design. Cartilage explants were used to model confined defects. BioCartilage was mixed with BMC, grafted into defects, and sealed with 1 of 5 fibrin glues. Constructs were cultured for 24 or 48 hours and then processed for live/dead microscopy. Chondrocyte and mesenchymal stem cell (MSC) adhesion on BioCartilage was assessed using scanning electron microscopy. Conditioned medium from cultures and the biologics used in the study were assayed for IL-1RA. The protein footprint of BioCartilage was determined using bottom-up proteomics. Results. BioCartilage supported chondrocyte and MSC attachment within 24 hours, and cell viability was retained in all constructs at 24 and 48 hours. Fibrin glue did not inhibit cell attachment. BMC had the highest concentration of IL-1RA. Proteomics yielded 254 proteins, including collagens, proteoglycans, and several bioactive proteins with known anabolic roles including cartilage oligomeric matrix protein. Conclusions. This study suggests that BioCartilage has the chemical composition and architecture to support cell adherence and migration and to provide bioactive proteins, which together should have biologics advantages in cartilage repair beyond its role as a scaffold.

Thickness of the Stifle Joint Articular Cartilage in Different Large Animal Models of Cartilage Repair and Regeneration

OBJECTIVE

Regulatory guidelines for preclinical cartilage repair studies suggest large animal models (e.g., sheep, goat, [mini]-pig, or horse) to obtain results representative for humans. However, information about the 3-dimensional thickness of articular cartilage at different implantation sites in these models is limited.

DESIGN

To identify the most suitable site for experimental surgery, cartilage thickness at the medial femoral condyle (MFC), lateral femoral condyle (LFC), and trochlea in ovine, caprine, and porcine cadaver stifle joints was systematically measured using hematoxylin-eosin staining of 6 µm paraffin sections and software-based image analysis.

RESULTS

Regarding all ventral-dorsal regions of the MFC, goat showed the thickest articular cartilage (maximal mean thickness: 1299 µm), followed by sheep (1096 µm) and mini-pig (604 µm), with the highest values in the most ventral and dorsal regions. Also for the LFC, the most ventral regions showed the thickest cartilage in goat (maximal mean thickness: 1118 µm), followed by sheep (678 µm) and mini-pig (607 µm). Except for the mini-pig, however, the cartilage thickness on the LFC was consistently lower than that on the MFC. The 3 species also differed along the transversal measuring points on the MFC and LFC. In contrast, there were no consistent differences for the regional cartilage thickness of the trochlea among goat and sheep (≥780 µm) and mini-pig (≤500 µm).

CONCLUSIONS

Based on their cartilage thickness, experimental defects on goat and sheep MFC may be viable options for preclinical cartilage repair studies, in addition to well-established horse models.

No Effect of Platelet-Rich Plasma Injections as an Adjuvant to Autologous Cartilage Chips Implantation for the Treatment of Chondral Defects

BACKGROUND

Repair of chondral injuries using cartilage chips has recently demonstrated clinical feasibility. Autologous platelet-rich plasma (PRP) is a potential promising technique for improving healing response during cartilage repair.

PURPOSE

To assess the cartilage repair tissue quality after autologous cartilage chips treatment (CC) with and without repeated local injections of PRP for the treatment of full-thickness focal chondral defects of the knee.

MATERIALS AND METHODS

Two full-thickness chondral defects (Ø = 6 mm) were created in the medial and lateral trochlea facets of each knee in 6 skeletally mature Göttingen minipigs. The 2 treatment groups were (1) CC with 1 weekly PRP injection for 3 weeks (n = 12) and (2) CC alone (n = 12). The animals were euthanized after 6 months. Samples of whole blood and PRP were analyzed for concentrations of platelets and nucleated cells. The composition of the cartilage repair tissue was assessed using gross appearance assessment, histomorphometry, and semiquantitative scoring (ICRS II).

RESULTS

Histological evaluation demonstrated no significant difference in the content of hyaline cartilage (CC + PRP: 18.7% vs. CC: 19.6%), fibrocartilage (CC + PRP: 48.1% vs. CC: 51.8%), or fibrous tissue (CC + PRP: 22.7% vs. CC: 21.8%) between the treatment groups. Macroscopic evaluation did not demonstrate any difference between groups.

CONCLUSIONS

PRP injections after CC in the treatment of full-thickness cartilage injuries demonstrated no beneficial effects in terms of macroscopic and histologic composition of cartilage repair tissue.

The Effect of Single vs Serial Platelet-Rich Plasma Injections in Osteochondral Lesions Treated With Microfracture: An In Vivo Rabbit Model

BACKGROUND

Biological adjuvants are used after a musculoskeletal injury to improve healing, decrease inflammation, and restore joint homeostasis. Work on 1 such adjuvant, platelet-rich plasma (PRP), has suggested a positive effect when introduced during cartilage repair. However, it remains unknown whether healing osteochondral injuries benefit from serial PRP injections.

PURPOSE

To evaluate the effects of serial PRP injections versus a single PRP injection on reparative cartilaginous tissue, subchondral bone remodeling, and the expression of inflammatory cytokines in joint synovium.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 48 New Zealand White rabbits were randomly assigned to receive 1 (1P), 2 (2P), or 3 (3P) PRP injections. Cylindrical full-thickness cartilage defects (2.9 × 2.9 mm) with microdrillings (0.6-mm diameter) were created on the medial condyles of both knees. PRP was injected into the right knee after closure (groups 1P, 2P, and 3P), at 2 weeks after surgery (groups 2P and 3P), and at 4 weeks after surgery (group 3P). The left knees did not receive any PRP injections. A total of 6 rabbits in each group were euthanized at 3, 6, and 12 weeks postoperatively. Cartilage repair tissue was assessed using the Goebel macroscopic and modified International Cartilage Regeneration & Joint Preservation Society (ICRS) histological scoring systems. Subchondral bone remodeling was evaluated by micro-computed tomography analysis (micro-CT). Inflammatory cytokine levels were assessed by quantitative polymerase chain reaction.

RESULTS

No significant differences were found for the mean macroscopic score between the PRP groups at 12 weeks (control, 6.1 ± 3.3; group 1P, 3.4 ± 2.7; group 2P, 4.2 ± 2.9; group 3P, 0.7 ± 1.5). All PRP groups had a significantly higher mean modified ICRS histological score compared with the control group, but no significant difference was found among the PRP groups. No significant differences were seen in outcomes for the tested micro-CT parameters or cytokine expression levels.

CONCLUSION

Serial PRP injections conferred no apparent advantage over single injections according to evaluations of the macroscopic and histological appearance of the cartilaginous tissue, subchondral bone healing, and inflammatory cytokine expression levels in the synovium.

CLINICAL RELEVANCE

The use of PRP as a biological adjuvant to bone marrow stimulation for osteochondral lesions has the potential to enhance the quality of regenerative cartilaginous tissue. We recommend only a single PRP injection if the use of PRP is indicated by the operating surgeon as an adjuvant therapy for osteochondral lesions.

Subchondral and intra-articular injections of bone marrow concentrate are a safe and effective treatment for knee osteoarthritis: a prospective, multi-center pilot study

PURPOSE

Subchondral bone is becoming a treatment target for knee OA patients, with promising early findings on the use of bone marrow aspirate concentrate (BMAC). The aim of this prospective, multi-centric pilot study was to evaluate safety as well as clinical and MRI outcomes of a combined approach of intra-articular and subchondral BMAC injections.

METHODS

Thirty patients (19 men, 11 women, 56.4 ± 8.1 years) with symptomatic knee OA were treated with a combination of an intra-articular and two subchondral BMAC injections (femoral condyle and tibial plateau). Patients were evaluated at baseline and at 1-3-6-12 months of follow-up with the IKDC subjective, VAS, KOOS, and EQ-VAS scores. The MRI evaluation was performed with the WORMS score.

RESULTS

No major complications were reported and only two patients were considered treatment failures, requiring a new injective or surgical treatment. The IKDC subjective score improved significantly from 40.5 ± 12.5 to 59.9 ± 16.1 at 3 months, 59.1 ± 12.2 at 6 months, and 62.6 ± 19.4 at 12 months (p < 0.0005). A similar improvement was reported for VAS pain and all KOOS subscales at all follow-ups, while EQ-VAS did not show any significant improvement. The MRI analysis showed a significant bone marrow edema reduction (p = 0.003), while the remaining WORMS parameters did not show any significant changes.

CONCLUSION

The pilot evaluation of this combined BMAC injective treatment showed safety and positive outcome up to 12 months of follow-up in patients with symptomatic knee OA associated with subchondral bone alterations. These findings suggest that targeting both subchondral bone and joint environment can provide promising results, and that BMAC can be a valid option for this combined approach to treat knee OA.

Use of autologous products for the treatment of joint and soft tissue disease in horses: A systematic review

BACKGROUND

Soft tissue injuries and joint disease are the predominate causes of lameness in the equine athlete and these pathologies carry a guarded prognosis for a return to previous performance. Recently the use of autologous products has become more widespread as a treatment in equine sports medicine. However, the efficacy of these products is yet to be fully established.

OBJECTIVE

To evaluate the current published evidence base regarding the efficacy of autologous products in soft tissue injuries and joint disease.

METHODS

A systematic review of English articles using MEDLINE, EMBASE and Web of Science databases from 1980 to 2017. The search strategy identified 1594 papers for review.

RESULTS

Fifty-eight papers were included in this review, 28 of which were randomised controlled trials. Significant benefit was reported under several parameters, most notably in the use of autologous chondrocytes in artificially induced cartilage defects on histology. One paper documented a significant clinical response under lameness examination.

CONCLUSION

The current literature shows that the treatment of soft tissue injury and cartilage disease with autologous products is safe and that the use of some products can give significant benefit on some outcome measures. True clinical significance is yet to be demonstrated with any product.

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

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

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

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

Arthroscopic Subchondral Drilling Followed by Injection of Peripheral Blood Stem Cells and Hyaluronic Acid Showed Improved Outcome Compared to Hyaluronic Acid and Physiotherapy for Massive Knee Chondral Defects: A Randomized Controlled Trial

PURPOSE

The purpose of this study was to evaluate the safety and efficacy of intra-articular injections of autologous peripheral blood stem cells (PBSCs) plus hyaluronic acid (HA) after arthroscopic subchondral drilling into massive chondral defects of the knee joint and to determine whether PBSC therapy can improve functional outcome and reduce pain of the knee joint better than HA plus physiotherapy.

METHODS

This is a dual-center randomized controlled trial (RCT). Sixty-nine patients aged 18 to 55 years with International Cartilage Repair Society grade 3 and 4 chondral lesions (size ≥3 cm²) of the knee joint were randomized equally into (1) a control group receiving intra-articular injections of HA plus physiotherapy and (2) an intervention group receiving arthroscopic subchondral drilling into chondral defects and postoperative intra-articular injections of PBSCs plus HA. The coprimary efficacy endpoints were subjective International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS)-pain subdomain measured at month 24. The secondary efficacy endpoints included all other KOOS subdomains, Numeric Rating Scale (NRS), and Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scores.

RESULTS

At 24 months, the mean IKDC scores for the control and intervention groups were 48.1 and 65.6, respectively (P < .0001). The mean for KOOS-pain subdomain scores were 59.0 (control) and 86.0 (intervention) with P < .0001. All other KOOS subdomain, NRS, and MOCART scores were statistically significant (P < .0001) at month 24. Moreover, for the intervention group, 70.8% of patients had IKDC and KOOS-pain subdomain scores exceeding the minimal clinically important difference values, indicating clinical significance. There were no notable adverse events that were unexpected and related to the study drug or procedures.

CONCLUSIONS

Arthroscopic marrow stimulation with subchondral drilling into massive chondral defects of the knee joint followed by postoperative intra-articular injections of autologous PBSCs plus HA is safe and showed a significant improvement of clinical and radiologic scores compared with HA plus physiotherapy.

LEVEL OF EVIDENCE

Level I, RCT.

Comparison of Bone Marrow Aspirate Concentrate and Allogenic Human Umbilical Cord Blood Derived Mesenchymal Stem Cell Implantation on Chondral Defect of Knee: Assessment of Clinical and Magnetic Resonance Imaging Outcomes at 2-Year Follow-Up

Biological repair of cartilage lesions remains a significant clinical challenge. A wide variety of methods involving mesenchymal stem cells (MSCs) have been introduced. Because of the limitation of the results, most of the treatment methods have not yet been approved by the Food and Drug Administration (FDA). However, bone marrow aspirate concentrate (BMAC) and human umbilical cord blood derived mesenchymal stem cells (hUCB-MSCs) implantation were approved by Korea FDA. The aim of this study was to evaluate clinical and magnetic resonance imaging (MRI) outcomes after two different types of MSCs implantation in knee osteoarthritis. Fifty-two patients (52 knees) who underwent cartilage repair surgery using the BMAC (25 knees) and hUCB-MSCs (27 knees) were retrospectively evaluated for 2 years after surgery. Clinical outcomes were evaluated according to the score of visual analogue scale (VAS), the International Knee Documentation Committee (IKDC) subjective, and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Cartilage repair was assessed according to the modified Magnetic Resonance Observation of Cartilage Repair Tissue (M-MOCART) score and the International Cartilage Repair Society (ICRS) cartilage repair scoring system. At 2-year follow-up, clinical outcomes including VAS, IKDC, and KOOS significantly improved (P < 0.05) in both groups; however, there were no differences between two groups. There was no significant difference in M-MOCART [1-year (P = 0.261), 2-year (P = 0.351)] and ICRS repair score (P = 0.655) between two groups. Both groups showed satisfactory clinical and MRI outcomes. Implantation of MSCs from BMAC or hUCB-MSCs is safe and effective for repairing cartilage lesion. However, large cases and a well-controlled prospective design with long-term follow-up studies are needed.

Injectable Scaffold for Bone Marrow Stem Cells and Bone Morphogenetic Protein-2 to Repair Cartilage

OBJECTIVE

The limits of the microfracture (MFX) treatment in terms of lesion size and long-term tissue functionality makes it necessary to investigate different alternatives to repair focal cartilage lesions. The present study aims at evaluating the efficacy of a minimally invasive approach against the conventional MFX to repair a chondral defect in rabbits. An injectable scaffold of BMP-2 pre-encapsulated in PLGA microspheres dispersed in a Pluronic F-127 solution is proposed as support of cells and controlled delivery system for the growth factor.

DESIGN

MFX was compared versus the injectable system seeded with mesenchymal stem cells (MSCs), both without BMP-2 and under controlled release of BMP-2 at 2 different doses (3 and 12 µg/scaffold). The different treatments were evaluated on a 4-mm diameter chondral defect model using 9 experimental groups of 4 rabbits (8 knees) each, throughout 24 weeks.

RESULTS

Histologically, all the treated groups, except MFX treated, responded significantly better than the control group (nontreated defect). Although no significant differences were found between the treated groups, only BMP(12), MSC-BMP(12), and MFX-BMP(3) groups showed nonsignificant differences when compared with the normal cartilage.

CONCLUSIONS

The hydrogel system proposed to control the release rate of the BMP-2 was safe, easily injectable, and also provided good support for cells. Treatments with MSCs or BMP-2 repaired efficiently the chondral lesion created in rabbits, being less invasive than MFX treatment.

Use of Extracellular Matrix Cartilage Allograft May Improve Infill of the Defects in Bone Marrow Stimulation for Osteochondral Lesions of the Talus

PURPOSE

To evaluate the effectiveness of extracellular matrix cartilage allograft (EMCA) as an adjuvant to bone marrow stimulation (BMS) compared with BMS alone in the treatment of osteochondral lesions of the talus.

METHODS

A retrospective cohort study comparing patients treated with BMS with EMCA (BMS-EMCA group) and BMS alone (BMS group) between 2013 and 2019 was undertaken. Clinical outcomes were evaluated with the Foot and Ankle Outcome Score (FAOS) preoperatively and postoperatively. Postoperative magnetic resonance imaging (MRI) scans were evaluated using the modified Magnetic Resonance Observation of Cartilage Repair Tissue score. Comparisons between groups were made with the Mann-Whitney U test for continuous variables and the Fisher exact test for categorical variables.

RESULTS

Twenty-four patients underwent BMS with EMCA (BMS-EMCA group), and 24 patients underwent BMS alone (BMS group). The mean age was 40.8 years (range, 19-60 years) in the BMS-EMCA group and 47.8 years (range, 24-60 years) in the BMS group (P = .060). The mean follow-up time was 20.0 months (range, 12-36 months) in the BMS-EMCA group and 26.9 months (range, 12-55 months) in the BMS group (P = .031). Both groups showed significant improvements in all FAOS subscales. No significant differences between groups were found in all postoperative FAOS values. The mean Magnetic Resonance Observation of Cartilage Repair Tissue score in the BMS-EMCA group was higher (76.3 vs 66.3) but not statistically significant (P = .176). The MRI analysis showed that 87.5% of the BMS-EMCA patients had complete infill of the defect with repair tissue; however, fewer than half of the BMS patients (46.5%) had complete infill (P = .015).

CONCLUSIONS

BMS with EMCA is an effective treatment strategy for osteochondral lesions of the talus and provides better cartilage infill in the defect on MRI. However, this did not translate to improved functional outcomes compared with BMS alone in the short term. Additionally, according to analysis of the minimal clinically important difference, there was no significant difference in clinical function scoring between the 2 groups postoperatively.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Comparison of Functional and Radiographic Outcomes of Talar Osteochondral Lesions Repaired With Micronized Allogenic Cartilage Extracellular Matrix and Bone Marrow Aspirate Concentrate vs Microfracture

BACKGROUND

Microfracture (MF) has been used historically to treat osteochondral lesions of the talus (OLTs), with favorable outcomes reported in approximately 80% to 85% of cases. However, MF repairs have been shown to degrade over time at long-term follow-up, suggesting that further study into optimal OLT treatment is warranted. The use of adjuvant extracellular matrix with bone marrow aspirate concentrate (ECM-BMAC) has not been extensively evaluated in the literature. We present a comparison of patient-reported and radiographic outcomes following ECM-BMAC repair vs traditional MF.

METHODS

Patients who underwent MF (n = 67) or ECM-BMAC (n = 62) treatment for an OLT were identified and their charts were retrospectively reviewed. Postoperative magnetic resonance imaging (MRI) was evaluated and patient-reported outcome scores, either Foot and Ankle Outcome Scores (FAOS) or Patient-Reported Measurement Information System (PROMIS) scores, were collected. MRIs were scored by a radiologist, fellowship trained in musculoskeletal radiology, using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) system. Radiographic and clinical outcomes were compared between groups.

RESULTS

On average, patients treated with ECM-BMAC demonstrated a higher total MOCART score compared to the MF group (73 ± SD 11.5 vs 54.0 ± 24.1; P = .0015). ECM-BMAC patients also had significantly better scores for the Infill, Integration, and Signal MOCART subcategories. Last, patients treated with ECM-BMAC had a lower rate of revision compared to those treated with MF (4.8% vs 20.9%; P = .007). FAOS scores were compared between groups, with no significant differences observed.

CONCLUSION

When comparing outcomes between patients treated for an OLT with ECM-BMAC vs traditional MF, we observed superior MRI results for ECM-BMAC patients. The rate of revision surgery was higher for MF patients, although patient-reported outcomes were similar between groups. The use of ECM-BMAC as an adjuvant therapy in the treatment of OLTs may result in improved reparative tissue when compared to MF.

LEVEL OF EVIDENCE

Level III, comparative series.

Microfracture Augmentation With Trypsin Pretreatment and Growth Factor-Functionalized Self-assembling Peptide Hydrogel Scaffold in an Equine Model

BACKGROUND

Microfracture augmentation can be a cost-effective single-step alternative to current cartilage repair techniques. Trypsin pretreatment combined with a growth factor-functionalized self-assembling KLD hydrogel ("functionalized hydrogel") has been shown to improve overall cartilage repair and integration to surrounding tissue in small animal models of osteochondral defects.

HYPOTHESIS

Microfracture combined with trypsin treatment and a functionalized hydrogel will improve reparative tissue quality and integration as compared with microfracture alone in an equine model.

STUDY DESIGN

Controlled laboratory study.

METHODS

Bilateral cartilage defects (15-mm diameter) were created on the medial trochlear ridge of the femoropatellar joints in 8 adult horses (16 defects total). One defect was randomly selected to receive the treatment, and the contralateral defect served as the control (microfracture only). Treatment consisted of 2-minute trypsin pretreatment of the surrounding cartilage, subchondral bone microfracture, and functionalized hydrogel premixed with growth factors (platelet-derived growth factor and heparin-binding insulin-like growth factor 1). After surgery, all horses were subjected to standardized controlled exercise on a high-speed treadmill. Clinical evaluation was conducted monthly, and radiographic examinations were performed at 2, 16, 24, 32, 40, and 52 weeks after defect creation. After 12 months, all animals were euthanized. Magnetic resonance imaging, arthroscopy, gross pathologic evaluation of the joint, histology, immunohistochemistry, and biomechanical analyses were performed. Generalized linear mixed models (with horse as random effect) were utilized to assess outcome parameters. When P values were <.05, pairwise comparisons were made using least squares means.

RESULTS

Improved functional outcome parameters were observed for the treatment group, even though mildly increased joint effusion and subchondral bone sclerosis were noted on imaging. Microscopically, treatment resulted in improvement of several histologic parameters and overall quality of repaired tissue. Proteoglycan content based on safranin O-fast green staining was also significantly higher in the treated defects.

CONCLUSION

Trypsin treatment combined with functionalized hydrogel resulted in improved microfracture augmentation.

CLINICAL RELEVANCE

Therapeutic strategies for microfracture augmentation, such as those presented in this study, can be cost-effective ways to improve cartilage healing outcomes, especially in more active patients.

Effects of porcine bone marrow-derived platelet-rich plasma on bone marrow-derived mesenchymal stem cells and endothelial progenitor cells

This study investigated the abundance of pro-regenerative growth factors in bone marrow-derived platelet-rich plasma (BM-PRP) and their effects on bone marrow-derived mesenchymal stem cells (BM-MSC) and bone marrow-derived endothelial progenitor cells (BM-EPC). Four 4-5 months-old domestic pigs were included, and each underwent bone marrow aspiration from its humerus bones and processed into bone marrow aspiration concentrate (BMAC) samples. The plasma and cellular portions of BMAC were subsequently separated and collected. The concentration of growth factors including BMP-2, PDGF-BB, TGF-β1 and VEGF in the plasma portion was measured and compared between BM-PRP and bone marrow-derived platelet-poor plasma (BM-PPP). It was found that platelet count was significantly higher in BM-PRP than in BM-PPP, but the concentration of above-mentioned growth factors was not significantly different between BM-PRP and BM-PPP. As most existing literature has indicated the regenerative potency of PRP, this study focused on assessing the effect of BM-PRP treatment on BM-MSC and BM-EPC proliferation, osteogenic differentiation and angiogenesis capacity by comparing samples with 2.5% BM-PRP treatment and samples without BM-PRP treatment (control). In response to BM-PRP treatment, the cellular doubling time increased with culturing time and was significantly shorter in the BM-PRP-treated samples than in control samples. For osteogenic differentiation, BM-PRP-treated BM-MSCs demonstrated a time-dependent increase in alkaline phosphatase (ALP) activity and expression levels of osteogenic differentiation markers. For the expression of angiogenic genes, none of the differences reached statistical significance despite a tendency of stronger expression at day 18 in BM-PRP-treated BM-EPCs. In conclusion, this in vitro study suggests that most BMP-2, PDGF-BB, TGF-β1 and VEGF-A contained in BM-PRP are not platelet-released and BM-PRP may have some stimulation (less than 1-fold) for MSC, EPC proliferation and MSC osteogenic differentiation.

Effectiveness of Platelet-Rich Plasma and Bone Marrow Aspirate Concentrate as Treatments for Chronic Hindlimb Proximal Suspensory Desmopathy

This retrospective study aimed to evaluate the clinical effect of bone marrow aspirate concentrate (BMAC) and leukocyte rich PRP (LR-PRP) compared to horses undergoing controlled exercise alone in horses with >3 months proximal suspensory desmopathy in hindlimbs (HPSD). Nighty-three horses were divided into three groups according to the treatment: a control (n = 22), LR-PRP (n = 46), and BMAC (n = 25) group. Lameness and ultrasound scores were recorded before treatment (T0) and at 6 months (T1) post-treatment. Records horses considered sound at evaluation and level of performance were additionally registered at 12 months (T2) and 18 months (T3) after treatment. The BMAC cytology profiles from 22 horses were also analysed and compared to clinical outcomes. The results at T1 showed that 9% (2/22) of the horses in the control group were sound compared to 59% (25/46) and 84% (21/25) in the LR-PRP and BMAC groups, respectively. Additionally, ultrasound scores at T1 in the BMAC and LR-PRP groups were improved in comparison with the control group (p = 0.02). At T2, 68% of the horses in the BMAC group and 39% of the horses in the LR-PRP group had returned to the previous performance level. At T3, a significantly higher percentage of horses in the LR-PRP (43%) and BMAC (72%) group were sound when compared to the control (4.6%) group (p = 0.02). Similarly, at T3, significantly more horses of the BMAC (16/25) and of the LR-PRP (15/46) group had returned to the previous or a higher performance level compared to the control (1/22) group (p = 0.01). No correlation was found between long-term clinical outcome and cytology profiles in the BMAC group. In conclusion, long-term outcomes of treatment with LR-PRP or BMAC are significantly better than conventional treatment of the hindlimb chronic PSD in horses. Additionally, BMAC yielded better lameness scores than LR-PRP at short- and long-term follow-up.

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.