Long-term Clinical Outcomes of One-Stage Cartilage Repair in the Knee With Hyaluronic Acid-Based Scaffold Embedded With Mesenchymal Stem Cells Sourced From Bone Marrow Aspirate Concentrate

Single-Stage Combined Autologous-Allogenic Cartilage Restoration: Surgical Technique

Articular cartilage injuries in young patients pose a notable treatment dilemma. Multiple reported techniques exist, although some of the most prominent methods currently rely on multiple procedures for chondrocyte harvest and colony expansion prior to implantation. The associated cost and effort this requires limits availability on a global basis, which creates a need for a more widely available cartilage procedure. This Technical Note describes a method for cartilage restoration that incorporates autologous chondrocytes in allogenic extracellular matrix, along with biologic augmentation all performed in a single stage.

Bone Marrow Aspirate Concentrate Combined with Ultra-Purified Alginate Bioresorbable Gel Enhances Intervertebral Disc Repair in a Canine Model: A Preclinical Proof-of-Concept Study

Although discectomy is commonly performed for lumbar intervertebral disc (IVD) herniation, the capacity for tissue repair after surgery is limited, resulting in residual lower back pain, recurrence of IVD herniation, and progression of IVD degeneration. Cell-based therapies, as one-step procedures, are desirable for enhancing IVD repair. This study aimed to investigate the therapeutic efficacy of a combination of newly developed ultra-purified alginate (UPAL) gel and bone marrow aspirate concentrate (BMAC) implantation for IVD repair after discectomy. Prior to an in vivo study, the cell concentration abilities of three commercially available preparation kits for creating the BMAC were compared by measuring the number of bone marrow mesenchymal stem cells harvested from the bone marrow of rabbits. Subsequently, canine-derived BMAC was tested in a canine model using a kit which had the highest concentration rate. At 24 weeks after implantation, we evaluated the changes in the magnetic resonance imaging (MRI) signals as well as histological degeneration grade and immunohistochemical analysis results for type II and type I collagen-positive cells in the treated IVDs. In all quantitative evaluations, such as MRI and histological and immunohistochemical analyses of IVD degeneration, BMAC-UPAL implantation significantly suppressed the progression of IVD degeneration compared to discectomy and UPAL alone. This preclinical proof-of-concept study demonstrated the potential efficacy of BMAC-UPAL gel as a therapeutic strategy for implementation after discectomy, which was superior to UPAL and discectomy alone in terms of tissue repair and regenerative potential.

Review of Caplan (1991) on cell-based therapeutic technology using Mesenchymal Stem Cells

This classic discusses the original 1991 publication 'Mesenchymal Stem Cells (MSCs)' by Dr. Caplan on the emergence of a new therapeutic technology of self-cell repair using MSCs. After the original classic publication, a large number of methods to regenerate injured tissue have been reported. Currently, MSCs are used clinically to repair articular cartilage defects, liver cirrhosis, cerebral infarction, spinal cord injury, graft-versus-host disease and others. As a result, MSCs are considered one of the most important cell sources for regenerative medicine. An MSC has been demonstrated to be a multipotent stem cell in cell culture and was thought to contribute to the regeneration of injured tissue at transplant sites, but recently, the concept of MSCs has changed such that they are now referred to as "medicinal signaling cells," owing to their often indirect effects on tissue repair and regeneration. Regardless of the name, either mesenchymal stem cells or medicinal signaling cells, MSCs will be used to regenerate injured tissue more widely in the near future.

Transcriptomics Demonstrates Significant Biological Effect of Growing Stem Cells on RGD-Cotton Scaffold

Stem cell therapy provides a viable alternative treatment for degenerated or damaged tissue. Stem cells have been used either alone or in conjunction with an artificial scaffold. The latter provides a structural advantage by enabling the cells to thrive in three-dimensional (3D) settings, closely resembling the natural in vivo environments. Previously, we disclosed the development of a 3D scaffold made from cotton, which was conjugated with arginyl-glycyl-aspartic acid (RGD), to facilitate the growth and proliferation of mesenchymal stem cells (MSCs). This scaffold allowed the MSCs to adhere and proliferate without compromising their viability or their stem cell markers. A comprehensive analysis investigation of the molecular changes occurring in MSCs adhering to the cotton fibers will contribute to the advancement of therapy. The objective of this study is to analyze the molecular processes occurring in the growth of MSCs on a cotton-RGD conjugated-based scaffold by examining their gene expression profiles. To achieve this, we conducted an experiment where MSCs were seeded with and without the scaffold for a duration of 48 h. Subsequently, cells were collected for RNA extraction, cDNA synthesis, and whole-transcriptomic analysis performed on both populations. Our analysis revealed several upregulated and downregulated differently expressed genes in the MSCs adhering to the scaffold compared with the control cells. Through gene ontology analysis, we were able to identify enriched biological processes, molecular functions, pathways, and protein-protein interactions in these differentially expressed genes. Our data suggest that the scaffold may have the potential to enhance osteogenesis in the MSCs. Furthermore, our results indicate that the scaffold does not induce oxidative stress, inflammation, or aging in the MSCs. These findings provide valuable insights for the application of MSCs in tissue engineering and regenerative medicine.

Protecting the regenerative environment: selecting the optimal delivery vehicle for cartilage repair-a narrative review

Focal cartilage defects are common in youth and older adults, cause significant morbidity and constitute a major risk factor for developing osteoarthritis (OA). OA is the most common musculoskeletal (MSK) disease worldwide, resulting in pain, stiffness, loss of function, and is currently irreversible. Research into the optimal regenerative approach and methods in the setting of either focal cartilage defects and/or OA holds to the ideal of resolving both diseases. The two fundamentals required for cartilage regenerative treatment are 1) the biological element contributing to the regeneration (e.g., direct application of stem cells, or of an exogenous secretome), and 2) the vehicle by which the biological element is suspended and delivered. The vehicle provides support to the regenerative process by providing a protective environment, a structure that allows cell adherence and migration, and a source of growth and regenerative factors that can activate and sustain regeneration. Models of cartilage diseases include osteochondral defect (OCD) (which usually involve one focal lesion), or OA (which involves a more diffuse articular cartilage loss). Given the differing nature of these models, the optimal regenerative strategy to treat different cartilage diseases may not be universal. This could potentially impact the translatability of a successful approach in one condition to that of the other. An analogy would be the repair of a pothole (OCD) versus repaving the entire road (OA). In this narrative review, we explore the existing literature evaluating cartilage regeneration approaches for OCD and OA in animal then in human studies and the vehicles used for each of these two conditions. We then highlight strengths and challenges faced by the different approaches presented and discuss what might constitute the optimal cartilage regenerative delivery vehicle for clinical cartilage regeneration.

Cartilage's Contribution in Otology: A Comprehensive Review of Its Role in Ear Surgery

This comprehensive review thoroughly examines the pivotal role of cartilage in otologic surgery, elucidating its multifaceted contributions to both cosmetic and functional outcomes. From reconstructing the external ear to reinforcing the tympanic membrane and restoring the ossicular chain, cartilage emerges as a versatile and resilient biological material with unique properties that make it an invaluable resource for otologic surgeons. The review explores the nuances of cartilage's applications in various surgical contexts, emphasizing its significance in promoting tissue regeneration and healing. The text delves into advancements in tissue engineering, biodegradable scaffolds, and 3D printing technology, pointing toward a future where more precise and personalized interventions may redefine the landscape of otologic surgery. The convergence of these innovations holds the promise of elevating the standard of care, minimizing complications, and improving the quality of life for patients undergoing cartilage-based otologic procedures. This synthesis of current knowledge and future possibilities provides a valuable resource for otologists, surgeons, and researchers in the dynamic field of otology.

Return to Play After Knee Articular Cartilage Restoration: Surgical Options, Rehabilitation Protocols, and Performance Outcomes

PURPOSE OF REVIEW

Numerous cartilage restoration techniques have proven to be effective in the treatment of articular cartilage defects. The ultimate goal of these procedures is to improve pain and function, thereby increasing the likelihood of a patient's return to physical activity. Postoperative rehabilitation is a key component for a successful and expedient return to activities. The purpose of this article is to review the current literature regarding common surgical options, rehabilitation protocols, and performance outcomes after operative treatment of articular cartilage defects.

RECENT FINDINGS

Studies have demonstrated improved short- to long-term outcomes in a majority of techniques. However, the clinical benefits of microfracture are short-lived, which has led to the use of alternative procedures. Rehabilitation protocols are not standardized, but emphasis has been placed on bracing, weightbearing, early continuous passive range of motion, and strengthening to improve function. There is growing evidence to suggest that accelerated rehabilitation after matrix-induced autologous chondrocyte implantation may result in superior outcomes compared to delayed rehabilitation. Overall, most techniques result in satisfactory rates of return to play, though existing comparative studies typically include patients with heterogeneous pathology, complicating effective synthesis of outcomes data. In appropriately selected patients, cartilage restoration procedures after articular cartilage injury result in favorable patient-reported clinical outcomes and high rates of return to play. While studies emphasize the critical role that rehabilitation plays with respect to outcomes after surgery, there are substantial inconsistencies in protocols across techniques.

Rehabilitation of Soccer Players' Knee Injuries: Cartilage Reconstruction, Anterior Cruciate Ligament Surgery, and Intensive Recovery-A Pilot Study

Knee injuries, particularly anterior cruciate ligament (ACL) damage and cartilage defects, are highly prevalent among athletes and affect their sports performance and long-term joint function. The purpose of this research was to evaluate the effectiveness of a comprehensive combination therapy approach for individuals with ACL and cartilage injuries. Twelve professional soccer players aged 18 to 30 years underwent bone-tendon-bone ACL reconstruction, microfracture cartilage repair surgery, and hyaluronic acid scaffold treatment. Early postoperative rehabilitation included immediate supervised physiotherapy and complete weight bearing. Follow-up assessments involved clinical evaluations, functional joint assessments, and magnetic resonance imaging (MRI) scans to measure cartilage defect repair and symptom alleviation. The results showed that patients resumed pain-free activities within 3-4 weeks and returned to their pre-injury level within 4.5 months. MRI demonstrated the absence of inflammatory reactions, repair of marrow edema, and the emergence of new cartilage. Six months and one year after surgery, the Knee Injury and Osteoarthritis Outcome Score (KOOS) and the Short Form (36) Health Survey (SF-36) questionnaire results demonstrated considerable improvement in patients' health condition and quality of life. Overall, the study suggests that the combination of Hyalofast membranes, microfracture surgery, tissue adhesive, and intensive postoperative physical therapy may be a potential alternative to commonly used treatments for patients with ACL rupture, allowing them to recover efficiently and return to sports activities.

Autologous Osteochondral Grafts for Knee Osteochondral Diseases Result in Good Patient-Reported Outcomes in Patients Older Than 60 Years

Purpose

This study aims to examine the clinical autologous osteochondral grafts (AOG) outcomes for knee osteochondral diseases at operative ages >60 years, and to determine whether patients are able to sit straight in Japanese style after AOG.

Methods

All patients who underwent AOG for knee osteochondral diseases between November 2001 and April 2018 were retrospectively identified. The inclusion criteria were AOG only without osteotomy, operative ages between 60 and 79 years, >2 years of follow-up, and involved femorotibial angle between 169° and 179° (normal alignment). Patients who underwent osteotomy to improve knee alignment and patients with inflammatory diseases such as rheumatoid arthritis were excluded. The patients' knee symptoms and their clinical outcome were evaluated according to the criteria of the knee scoring system of the Japanese Orthopedic Association (JOA), International Knee Documentation Committee (IKDC) subjective score, and the ability of straight sitting in Japanese style.

Results

This study enrolled 57 cases and 60 knee joints during the study period. The follow-up ratio was 85.1%. Moreover, 14 men and 43 women and 29 right and 31 left knee joints were included in this study. The mean operative age and mean follow-up period were 67.8 years (range 60-76 years) and 81.1 months (range 24-167 months), respectively. In addition, the study involved 30 cases and 32 knee joints (60s group), and 27 cases and 28 knee joints (70s group). Moreover, 34 cases and 36 knee joints had osteonecrosis (ON group), and 23 cases and 24 knee joints had cartilage injury (CI group). The IKDC subjective and JOA scores in both the 60s and 70s groups showed significant differences: 2 years after AOG ＞at the follow-up period, ＞at the preoperative period. The scores in both the CI and ON groups showed similar significant differences. Furthermore, 8.3% and 53.5% of the patients could sit straight in Japanese style at the preoperative period and 2 years after AOG, respectively.

Conclusion

Even if the patient's operative age was >60 years, the AOG only for their knee osteochondral diseases had good clinical outcomes, including the ability to sit straight in Japanese style.

Level of Evidence

IV, Therapeutic case series Key words: autologous osteochondral grafts, aged patients, clinical outcome, knee joint, straight sitting in Japanese style.

Patellar Cartilage Bossing Causing Patellofemoral Pain After Cartilage Repair With Hyalofast® Scaffold and Bone Marrow Aspirate Concentrate (BMAC)

Chondral lesions of the knee are common orthopedic issues encountered in daily practice. Hyalofast® (Anika Therapeutics, Bedford, Massachusetts) grafting with bone marrow aspirate concentrate (BMAC) has been shown, in numerous studies, to be clinically efficacious in the surgical treatment of these lesions. We describe a case of chondral lesions in the knee initially successfully treated with arthroscopic chondroplasty and Hyalofast® grafting with BMAC, but who subsequently developed patellar cartilage bossing, causing anterior patellofemoral joint pain eight months after surgery. A 48-year-old gentleman underwent arthroscopic chondroplasty and mini-open cartilage repair with Hyalofast® and BMAC after presenting with right knee pain and swelling affecting his ability to participate in sports. His initial recovery was unremarkable, but he subsequently developed anterior knee pain exacerbated by stair climbing and jogging eight months after the initial surgery. Magnetic resonance imaging revealed bossing of the Hyalofast® graft over the central patella, and intraoperative testing confirmed the impingement. The patient's symptoms resolved immediately following arthroscopic debridement. While Hyalofast® grafting and BMAC remain viable options in the treatment of chondral lesions in the knee, the inability to predict the amount of cartilage repair and recovery may result in pain and impingement symptoms, and surgeons should be aware of such possible complications.

Hyalofast Cartilage Repair Surgery with a Full Load-Bearing Rehabilitation Program One Day after Operation Reduces the Time for Professional Athletes to Return to Play

Background and Objectives: This study evaluated the effectiveness of Hyalofast cartilage repair surgery with an early, full load-bearing rehabilitation program one day after the operation for reducing the time needed for professional athletes to return to play. Materials and Methods: This prospective study included 49 patients aged between 19 and 38 years who had undergone surgical reconstruction of cartilage using the microfracture technique combined with a Hyalofast scaffold. All patients were active professional athletes. Early rehabilitation was implemented from the first postoperative day, fully loading the operated limb. A clinical evaluation was based on the KOOS and SF-36 questionnaires used during subsequent follow-up visits. All patients underwent magnetic resonance imaging (MRI) to evaluate the effect of the surgery after one year. Results: The clinical results demonstrated a statistically significant improvement in the number of complaints about pain and in the quality of life of the patients, measured in all of the applied scales, with comparisons made between six months or one year post-surgery and pre-surgery. Importantly for athletes, the parameter related to sports and recreation improved from 14 ± 11.1 to 95 ± 7.7 6 months after surgery and to 99.8 ± 1.8 one year after surgery. The overall quality of life score improved from 30 ± 18 to 88 ± 8.8 one year after surgery. Conclusions: These results show that this approach significantly shortened the time needed for the athletes to return to sports at the same level as before the surgery (athletes returned to sports in approximately 2.5-3 months). The mean follow-up time was 19.75 months. This technique can be considered a viable option for the treatment of cartilage injuries in professional athletes, allowing them to return to play more quickly in a safe and healthy way.

A systematic review, umbrella review, and quality assessment on clinical translation of stem cell therapy for knee osteoarthritis: Are we there yet?

BACKGROUND

The success of stem cell therapy for knee osteoarthritis (KOA) in preclinical animal models has accelerated the pace of clinical translation. However, it remains uncertain whether the current scientific evidence supports the clinical application of stem cells in treating KOA. A comprehensive evaluation of the safety and efficacy of stem cell therapies and scientific evidence quality is necessary.

METHODS

Using "stem cells" and "knee osteoarthritis" as the search terms, several databases, including PubMed, Web of Science, Cochrane, Embase, and Clinicaltrials.gov, were searched on August 25, 2022, and updated on February 27, 2023. Clinical studies that reported adverse reactions (ARs) of stem cell therapy in KOA patients were included without limiting the type of studies. Quantitative systematic reviews of stem cell therapy for KOA that conducted meta-analysis were included. Two researchers conducted literature screening and data extraction independently, and the evidence quality was evaluated according to the Institute of Health Economics and AMSTAR 2 criteria.

RESULTS

Fifty clinical studies and 13 systematic reviews/meta-analyses (SRs/MAs) were included. Nineteen ARs were reported in 50 studies, including five knee-related ARs, seven common ARs, and seven other ARs. Some studies reported over 10% prevalence of knee pain (24.5%; 95% CI [14.7%, 35.7%]), knee effusion (12.5%; 95% CI [4.8%, 22.5%]), and knee swelling (11.9%; 95% CI [3.5%, 23.5%]). Additionally, two studies have reported cases of prostate cancer and breast tumors, respectively. However, these two studies suggest that stem cell therapy does not bring significant ARs to patients. SRs/MAs results revealed that stem cell therapy relieved pain in patients over time but did not improve knee function. However, current clinical studies have limited evidence regarding study objectives, test designs, and patient populations. Similarly, SRs/MAs have inadequate evidence regarding study design, risk of bias assessment, outcome description, comprehensive discussion, and potential conflicts of interest.

CONCLUSIONS

The inefficacy of stem cells, the risk of potential complications, and the limited quality of evidence from current studies precluded any recommendation for using stem cell products in patients with KOA. Clinical translation of stem cell therapies remains baseless and should be cautiously approached until more robust evidence is available. PROSPERO registration number: CRD42022355875.

Scaffolds for Cartilage Tissue Engineering from a Blend of Polyethersulfone and Polyurethane Polymers

In recent years, one of the main goals of cartilage tissue engineering has been to find appropriate scaffolds for hyaline cartilage regeneration, which could serve as a matrix for chondrocytes or stem cell cultures. The study presents three types of scaffolds obtained from a blend of polyethersulfone (PES) and polyurethane (PUR) by a combination of wet-phase inversion and salt-leaching methods. The nonwovens made of gelatin and sodium chloride (NaCl) were used as precursors of macropores. Thus, obtained membranes were characterized by a suitable structure. The top layers were perforated, with pores over 20 µm, which allows cells to enter the membrane. The use of a nonwoven made it possible to develop a three-dimensional network of interconnected macropores that is required for cell activity and mobility. Examination of wettability (contact angle, swelling ratio) showed a hydrophilic nature of scaffolds. The mechanical test showed that the scaffolds were suitable for knee joint applications (stress above 10 MPa). Next, the scaffolds underwent a degradation study in simulated body fluid (SBF). Weight loss after four weeks and changes in structure were assessed using scanning electron microscopy (SEM) and MeMoExplorer Software, a program that estimates the size of pores. The porosity measurements after degradation confirmed an increase in pore size, as expected. Hydrolysis was confirmed by Fourier-transform infrared spectroscopy (FT-IR) analysis, where the disappearance of ester bonds at about 1730 cm−1 wavelength is noticeable after degradation. The obtained results showed that the scaffolds meet the requirements for cartilage tissue engineering membranes and should undergo further testing on an animal model.

Outcome of Intra-articular Injection of Total Stromal Cells and Platelet-Rich Plasma in Primary Knee Osteoarthritis: A Randomized Clinical Trial

INTRODUCTION

 Mesenchymal stem cell (MSC) therapy appeared promising in knee osteoarthritis (OA). We examined if a single intra-articular (IA) autologous total stromal cells (TSC) and platelet-rich plasma (PRP) injection improved knee pain, physical function, and articular cartilage thickness in knee OA.

METHODS

 The study was performed in the physical medicine and rehabilitation department of Bangabandhu Shaikh Mujib Medical University, Dhaka, Bangladesh. Knee OA was diagnosed according to the American College of Rheumatology criteria and randomly assigned to treatment (received TSC and PRP) and control groups. Kallgreen-Lawrance (KL) scoring system was used to grade primary knee OA. The Visual Analogue Scale (VAS, 0-10 cm) for pain, WOMAC (Western Ontario and McMaster Universities Arthritis Index) for physical function, and medial femoral condylar cartilage (MFC) thickness (millimeters) under ultrasonogram (US) were documented and compared between groups before and after treatment. Statistical Package analyzed data for Social Scientists (SPSS 22.0; IBM Corp, Armonk, NY) was used for data analysis. Pre- and post-intervention outcomes were measured using the Wilcoxon-sign test, whereas Mann-Whitney U-test calculated the difference between groups; a p-value <0.05 was considered statistically significant.  Result: In the treatment group, 15 received IA-TSC and PRP preparation, and in the control group, 15 patients received no injection, but quadricep muscle-strengthening exercise. There was no significant difference between groups regarding VAS for pain, WOMAC physical function, and cartilage thickness before starting the treatment and two weeks after intervention. VAS for pain and WOMAC physical function scores improved profoundly in the treatment group after 12 and 24 weeks of intervention; the pain and physical function scores difference between groups was also significant. However, significant mean femoral cartilage thickness was not changed until the end of 24 weeks (U=175.00, p=0.009 two-tailed and U= 130.00, p=0.016 two-tailed, respectively, for right and left knee).

CONCLUSION

 Single TSC and PRP injection reduces knee pain and improves physical function and cartilage thickness in knee OA. While pain and physical function improvement happen earlier, cartilage thickness change takes more time.

Satisfactory clinical outcomes with autologous matrix-induced chondrogenesis in the treatment of grade IV chondral injuries of the knee

OBJECTIVE

The research aims to evaluate short- and medium-term outcomes of patients treated using autologous matrix-induced chondrogenesis (AMIC) with a hyaluronic acid scaffold (Hyalofast, Anika Therapeutics, MA, USA) in grade IV chondral lesions according to the Outerbridge classification in the knee.

METHODS

This is a multicentre, non-randomized, retrospective study conducted between 2017 and 2022. To determine the clinical outcome of the patients, the follow-up was done with the subjective International Knee Documentation Committee (IKDC) score, pre-surgery, and with a follow-up at 12, 24, and 32 months.

RESULTS

Fifty patients (28 female) with a mean age of 45.9 ± 12.7 years were recruited. The mean size of the lesion was 3.5 cm², and the injuries located in the patella (30%) and trochlear groove (24%) were the most frequent. The total IKDC clinical score significantly increased from baseline to the 32 months of follow-up with a mean difference of 36.4 (95% CI, 29.1-43.7, p < 0.001). Besides, there was a statistically significant improvement in all categories of the IKDC (symptoms, sports activities, function, and activity of daily living) compared between pre-surgery and 24 and 32 months of follow-up. The patients younger than 45 years presented better clinical outcomes than older ones with a difference between medians of 10.40 (95% CI, 1.10-11.50, p = 0.0247), and a negative correlation was found between the 32-month IKDC score and the age. In addition, no statistically significant difference was found when comparing the last results of the IKDC between patients with and without associated surgical procedures or between patients with single and several lesions, neither nor between men and women. The level of satisfaction with the procedure of all the patients, on a score of 1-10, was on average 8 ± 1.5.

CONCLUSION

Results of this study indicate that patients who underwent the AMIC procedure with hyaluronic acid scaffold for the treatment of grade IV chondral lesions in the knee presented satisfactory results throughout the follow-up.

LEVEL OF EVIDENCE

Level IV.

The Mechanism of Action between Pulsed Radiofrequency and Orthobiologics: Is There a Synergistic Effect?

Radiofrequency energy is a common treatment modality for chronic pain. While there are different forms of radiofrequency-based therapeutics, the common concept is the generation of an electromagnetic field in the applied area, that can result in neuromodulation (pulsed radiofrequency—PRF) or ablation. Our specific focus relates to PRF due to the possibility of modulation that is in accordance with the mechanisms of action of orthobiologics. The proposed mechanism of action of PRF pertaining to pain relief relies on a decrease in pro-inflammatory cytokines, an increase in cytosolic calcium concentration, a general effect on the immune system, and a reduction in the formation of free radical molecules. The primary known properties of orthobiologics constitute the release of growth factors, a stimulus for endogenous repair, analgesia, and improvement of the function of the injured area. In this review, we described the mechanism of action of both treatments and pertinent scientific references to the use of the combination of PRF and orthobiologics. Our hypothesis is a synergic effect with the combination of both techniques which could benefit patients and improve the life quality.

Articular cartilage delamination at eight years following cellular-based repair procedures: a case reports

This report describes two cases of late cartilage delamination in two young adults after two different autologous cell-based techniques for cartilage restoration: 1. Matrix-assisted autologous chondrocyte implantation (MACI) and 2. Hyaluronic acid-bone marrow aspirate concentrate (HA-BMAC). Both cases demonstrate that even in patients who do not present with any ongoing symptoms after primary surgery, a cellular-based graft's subsequent delamination can occur later. It is possible that regardless of the technique used or the time passed since the surgery, a graft failure may occur at some level, causing delamination of a previously asymptomatic cartilage restoration graft and a traumatic event with long-term follow-up. Surgeons must be alert to this injury and describe histologic findings to determine where failure occurs.

Recent Developments and Current Applications of Organic Nanomaterials in Cartilage Repair

Regeneration of cartilage is difficult due to the unique microstructure, unique multizone organization, and avascular nature of cartilage tissue. The development of nanomaterials and nanofabrication technologies holds great promise for the repair and regeneration of injured or degenerated cartilage tissue. Nanomaterials have structural components smaller than 100 nm in at least one dimension and exhibit unique properties due to their nanoscale structure and high specific surface area. The unique properties of nanomaterials include, but are not limited to, increased chemical reactivity, mechanical strength, degradability, and biocompatibility. As an emerging nanomaterial, organic nanocomposites can mimic natural cartilage in terms of microstructure, physicochemical, mechanical, and biological properties. The integration of organic nanomaterials is expected to develop scaffolds that better mimic the extracellular matrix (ECM) environment of cartilage to enhance scaffold-cell interactions and improve the functionality of engineered tissue constructs. Next-generation hydrogel technology and bioprinting can be used not only for healing cartilage injury areas but also for extensive osteoarthritic degenerative changes within the joint. Although more challenges need to be solved before they can be translated into full-fledged commercial products, nano-organic composites remain very promising candidates for the future development of cartilage tissue engineering.

Comparison of 3 Cell-Free Matrix Scaffolds Used to Treat Osteochondral Lesions in a Rabbit Model

BACKGROUND

Various cell-free scaffolds are already in use for the treatment of osteochondral defects (OCDs); however, a gold standard material has not yet been defined.

PURPOSE

This study compared the macroscopic, histological, and scanning electron microscopy (SEM) characteristics of Chondro-Gide (CG), MaioRegen (MA), and poly-d,l-lactide-co-caprolactone (PLCL) cell-free scaffolds enhanced with small-diameter microfractures (SDMs) for OCDs in a rabbit model.

STUDY DESIGN

Controlled laboratory study.

METHODS

In total, 54 knees from 27 rabbits were used in this study. Three rabbits were sacrificed at the beginning of the study to form an intact cartilage control group (group IC). An OCD model was created at the center of the trochlea, and SDMs were generated in 24 rabbits. Rabbits with OCDs were divided into 4 groups (n = 12 knees per group) according to the cell-free scaffold applied: CG (group CG), MA (group MA), PLCL (group PLCL), and a control group (group SDM). Half of the rabbits were sacrificed at 1 month after treatment, while the other half were sacrificed at 3 months after treatment. Healed cartilage was evaluated macroscopically (using International Cartilage Regeneration & Joint Preservation Society [ICRS] classification criteria) and histopathologically (using modified O'Driscoll scores and collagen staining). Additionally, cell-free scaffold morphologies were compared using SEM analysis.

RESULTS

ICRS and modified O'Driscoll classification and staining with collagen type 1 and type 2 demonstrated significant differences among groups at both 1 and 3 months after treatment (P < .05). The histological characteristics of the group IC samples were superior to those of all other groups, except group PLCL, at 3 months after treatment (P < .05). In addition, the histological properties of group PLCL samples were superior to those of group SDM samples at both 1 and 3 months after treatment in terms of the modified O'Driscoll scores and type 1 collagen staining (P < .05). Concerning type 2 collagen staining intensity, the groups were ranked from highest to lowest at 3 months after treatment as follows: group PLCL (30.3 ± 2.6) > group MA (26.6 ± 1.2) > group CG (23.3 ± 2.3) > group SDM (18.9 ± 0.9).

CONCLUSION

OCDs treated with enhanced SDM using cell-free PLCL scaffolds had superior histopathological and microenvironmental properties, more hyaline cartilage, and more type 2 collagen compared with those treated using CG or MA scaffolds.

CLINICAL RELEVANCE

OCDs treated with PLCL cell-free scaffolds may have superior histopathological properties and contain more type 2 collagen than do OCDs treated with CG or MA cell-free scaffolds.

Patients seeking stem cell therapies-a prospective qualitative analysis from a Regenerative Medicine Consult Service

Despite patient demand for stem cell therapies (SCTs) for musculoskeletal conditions, there remains limited research on why patients seek SCTs or their sources of information. We employ three questions into a consult intake form: (1) Why are you interested in stem cell treatment for your condition? (2) How did you find out about stem cell treatment for your condition? (3) Have you contacted a stem cell clinic? Responses analyzed, using a qualitative content analysis approach to identify themes reveal many patients seek SCTs to treat pain or delay surgery which may align with some current clinical evidence while other patients express motivations as expected outcomes (e.g., SCTs are better than standard of care or can regenerate tissue) which are not supported by current medical evidence. These differences suggests that patient-centered counseling may help patients by addressing misconceptions and increasing health literacy about expected outcomes of SCTs for treating musculoskeletal conditions.

Methodological Flaws in Meta-Analyses of Clinical Studies on the Management of Knee Osteoarthritis with Stem Cells: A Systematic Review

(1) Background: Conclusions of meta-analyses of clinical studies may substantially influence opinions of prospective patients and stakeholders in healthcare. Nineteen meta-analyses of clinical studies on the management of primary knee osteoarthritis (pkOA) with stem cells, published between January 2020 and July 2021, came to inconsistent conclusions regarding the efficacy of this treatment modality. It is possible that a separate meta-analysis based on an independent, systematic assessment of clinical studies on the management of pkOA with stem cells may reach a different conclusion. (2) Methods: PubMed, Web of Science, and the Cochrane Library were systematically searched for clinical studies and meta-analyses of clinical studies on the management of pkOA with stem cells. All clinical studies and meta-analyses identified were evaluated in detail, as were all sub-analyses included in the meta-analyses. (3) Results: The inconsistent conclusions regarding the efficacy of treating pkOA with stem cells in the 19 assessed meta-analyses were most probably based on substantial differences in literature search strategies among different authors, misconceptions about meta-analyses themselves, and misconceptions about the comparability of different types of stem cells with regard to their safety and regenerative potential. An independent, systematic review of the literature yielded a total of 183 studies, of which 33 were randomized clinical trials, including a total of 6860 patients with pkOA. However, it was not possible to perform a scientifically sound meta-analysis. (4) Conclusions: Clinicians should interpret the results of the 19 assessed meta-analyses of clinical studies on the management of pkOA with stem cells with caution and should be cautious of the conclusions drawn therein. Clinicians and researchers should strive to participate in FDA and/or EMA reviewed and approved clinical trials to provide clinically and statistically valid efficacy.

The Role of Mesenchymal Stromal Cells in the Management of Knee Chondral Defects

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Mesenchymal stromal cells (MSCs) are a subset of progenitor cells that help to promote tissue healing and regeneration through the secretion of various cytokines and growth factors. Although technically pluripotent, MSCs in vivo rarely repair damaged tissue through direct differentiation and engraftment.

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Augmentation of traditional marrow stimulation techniques with MSCs has been theorized to improve repair tissue quality and defect fill. Clinical trials evaluating this technique are limited but have shown modest improvements compared with isolated marrow stimulation.

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Various scaffolds also have been utilized in combination with MSCs to treat focal chondral defects. Although the techniques described are heterogeneous, many have shown promising early clinical outcomes.

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Newer techniques involving 3-dimensional bioprinted scaffolds seeded with MSCs allow for the recreation of complex architecture, more closely resembling articular cartilage. These techniques are evolving and have not yet been studied in human clinical trials.

Past, present, and future of cartilage restoration: from localized defect to arthritis

BACKGROUND

Osteoarthritis, one of the most common joint diseases, is characterized by the loss of joint function due to articular cartilage destruction. Herein, we review current and previous research involving the clinical applications of arthritis therapy and suggest potential therapeutic options for osteoarthritis in the future.

PAST, PRESENT, AND FUTURE TREATMENT

The arthroscopic cartilage regeneration procedure or realignment osteotomy has been performed as a joint-conserving procedure in cases where conservative treatment for damaged articular cartilage and early osteoarthritis failed. If cartilage regeneration is ineffective or if the joint damage progresses, arthroplasty is the main treatment option. The need for biological arthritis treatment has expanded as the healthy lifespan of the global population has increased. Accordingly, minimally invasive surgical treatment has been developed for the treatment of damaged cartilage and early osteoarthritis. However, patients generally prefer to avoid all types of surgery, including minimally invasive surgery. Therefore, in the future, the treatment of osteoarthritis will likely involve injection or medication.

CONCLUSION

Currently, arthritis management primarily involves the surgical application of therapeutic agents to the joints. However, nonsurgical or prophylactic methods are expected to become mainstream arthritis therapies in the future.

[Surgical treatment of focal cartilage defects in the knee : Indications, techniques, modifications and results]

The treatment strategies for focal cartilage damage in the knee are multifarious. For established procedures, such as microfracturing (MFX), autologous matrix-induced chondrogenesis (AMIC), osteochondral transplantation (OCT) and autologous chondrocyte transplantation (ACT), well-founded, partly comparative long-term studies and overlapping size-dependent differential indications are available. Innovative cell sources, the utilization of biological scaffolds as well as biologic agents and various combinations, have recently become the focus of scientific attention; however, high regulatory demands are restricting their use in Germany. The success of every procedure is dependent on the appropriate indications, the treatment of comorbidities, such as axis deviations or ligamentous instability, the surgeon's experience and an adequate follow-up treatment.

Minimally invasive cell-based therapy for symptomatic bone marrow lesions of the knee: A prospective clinical study at 1 year

Bone Marrow Lesions (BMLs) are typical findings in magnetic resonance imaging (MRI) present in different pathologies, such as spontaneous insufficiency fractures, osteonecrosis, transient BML syndromes, osteoarthritis, and trauma. The etiology and evolution of BMLs in multiple conditions remain unclear. There is still no gold standard protocol for the treatment of symptomatic BMLs in the knee. The biologic augmentation by Osteo Core Plasty is a new treatment modality showing promising results reducing pain with the aim to stop the progression of the disease. The purpose of this prospective study is to report the clinical outcomes and safety of Osteo Core Plasty for the treatment of symptomatic BMLs in the knee. Fifteen patients with symptomatic BMLs of the knee treated with the Osteo Core Plasty technique were included and followed prospectively for a minimum of 12 months. Each patient was evaluated before the surgery and respectively at 6 and 12 months using the Tegner Score, Marx Score, the International Knee Documentation Committee (IKDC), the Knee Injury and Osteoarthritis Outcome Score (KOOS) divided in pain, activity daily living (ADL) and Quality of Life (QOL) subscale and the Visual Analogue Scale (VAS) for pain. All clinical scores except Tegner and Marx score showed an overall statistically significant improvement through the entire follow-up (p<0.05) and a significant improvement (p<0.05) between each follow-up period (T0 versus T1; T0 versus T2; T1 versus T2). No complications were reported. These preliminary results confirm that biological subchondral bone augmentation by Osteo Core Plasty technique is a safe and effective minimally invasive treatment option for symptomatic BMLs in the knee at 1-year follow-up. There is still a need for high-quality RCTs studies and systematic reviews in the future to enhance further treatment strategies in preventing or treating BMLs of the knee.

Histone deacetylase inhibitors attenuated interleukin-1β-induced chondrogenesis inhibition in synovium-derived mesenchymal stem cells of the temporomandibular joint

Aims

In the repair of condylar cartilage injury, synovium-derived mesenchymal stem cells (SMSCs) migrate to an injured site and differentiate into cartilage. This study aimed to confirm that histone deacetylase (HDAC) inhibitors, which alleviate arthritis, can improve chondrogenesis inhibited by IL-1β, and to explore its mechanism.

Methods

SMSCs were isolated from synovium specimens of patients undergoing temporomandibular joint (TMJ) surgery. Chondrogenic differentiation potential of SMSCs was evaluated in vitro in the control, IL-1β stimulation, and IL-1β stimulation with HDAC inhibitors groups. The effect of HDAC inhibitors on the synovium and condylar cartilage in a rat TMJ arthritis model was evaluated.

Results

Interleukin (IL)-1β inhibited the chondrogenic differentiation potential of SMSCs, while the HDAC inhibitors, suberoylanilide hydroxamic acid (SAHA) and panobinostat (LBH589), attenuated inhibition of IL-1β-induced SMSC chondrogenesis. Additionally, SAHA attenuated the destruction of condylar cartilage in rat TMJ arthritis model. IL-6 (p < 0.001) and matrix metalloproteinase 13 (MMP13) (p = 0.006) were significantly upregulated after IL-1β stimulation, while SAHA and LBH589 attenuated IL-6 and MMP13 expression, which was upregulated by IL-1β in vitro. Silencing of IL-6 significantly downregulated MMP13 expression and attenuated IL-1β-induced chondrogenesis inhibition of SMSCs.

Conclusion

HDAC inhibitors SAHA and LBH589 attenuated chondrogenesis inhibition of SMSC induced by IL-1β in TMJ, and inhibition of IL-6/MMP13 pathway activation contributes to this biological progress. This study provides a theoretical basis for the application of HDAC inhibitors in the treatment of TMJ arthritis.

Cite this article: Bone Joint Res 2022;11(1):40–48.

Biological Augments for Acetabular Chondral Defects in Hip Arthroscopy-A Scoping Review of the Current Clinical Evidence

PURPOSE OF REVIEW

A wide array of joint-preserving surgical techniques exists in the management of acetabular chondral defects (ACDs). The purpose of this review is to summarize the clinical outcomes of the recent biologics used to treat ACDs during hip arthroscopy.

RECENT FINDINGS

Increasing evidence is available for different biological solutions used in the hip. Studies have shown promising outcomes with minimal complications when using biologics as augmentation to microfracture (MF), including different scaffolds or stem cells, or to enhance autologous chondrocyte implantation (ACI). However, data so far is scarce, and more trials and longer follow-ups are needed to better delineate the appropriate indications and benefits for each technique. Presently, the level of evidence is low, but in general, biologics appear safe and trend toward beneficial compared to standard surgical techniques. Augmented MF is recommended for small to medium ACDs, and matrix-assisted ACI or three-dimensional ACI is recommended for medium to large defects.

Treatment of Patellofemoral Chondral Lesions Using Microfractures Associated with a Chitosan Scaffold: Mid-Term Clinical and Radiological Results

OBJECTIVE

To assess the clinical and radiological results of patellofemoral osteochondral lesions treated with microfractures associated with a chitosan scaffold.

DESIGN

A retrospective observational analytical study was performed. Fifteen patients with full-thickness patellofemoral osteochondral lesions were included. Quantity and quality of the reparation cartilage was assessed with the MOCART 2.0 score on a postoperative magnetic resonance imaging (MRI), and clinical outcomes were evaluated with pre- and postoperative Kujala score tests. Shapiro-Wilk test for normality was applied as well as Wilcoxon's signed rank test and Kruskal-Wallis H test for clinical scores within subjects and patella versus trochlea subgroups comparisons. Analysis of variance test was used for imaging subgroups comparison, with P < 0.05 defined as statistical significance.

RESULTS

Mean follow-up was 33.36 months (range 24-60 months). Postoperative Kujala scores improved an average of 19 points compared with the preoperative state (SE = 17.6; P < 0.001). No statistical difference was found through the clinical location assessment (P = 0.756), as well as the cartilage imaging assessment (P = 0.756). The mean MOCART 2.0 scale was 67.67 (range 50-85).

CONCLUSIONS

Treating full-thickness patellofemoral osteochondral lesions with microfractures associated with a chitosan scaffold proved to be effective regarding defect filling and symptomatic improvement.

Biologic Augmentation for the Operative Treatment of Osteochondral Defects of the Knee: A Systematic Review

Background:

Various surgical treatment options exist for repairing, replacing, or regenerating tissue to fill osteochondral defects. Biologic augmentation has been increasingly studied as an adjunct in the surgical treatment of osteochondral defects of the knee in animal and human models.

Purpose/Hypothesis:

The purpose of the study was to systematically review use of platelet-rich plasma (PRP) and bone marrow concentrate (BMC) augmentation in the surgical treatment of osteochondral knee defects and to describe the outcomes. It was hypothesized that both PRP and BMC augmentation will result in improved outcomes in osteochondral knee surgery in both animal and human models.

Study Design:

Systematic review.

Methods:

PubMed, MEDLINE, and Embase were searched for studies relating to PRP or BMC and treatment of osteochondral defects of the knee, from database inception to February 1, 2020. Included were articles that (1) studied PRP or BMC augmentation; (2) used osteochondral autograft, allograft, or biologic scaffold; and (3) treated osteochondral defects in the knee. Data on use of PRP or BMC, outcomes assessed, and results were recorded for each publication.

Results:

Of the 541 articles identified initially, 17 were included in the final review. Five articles studied osteochondral grafts in animals, 5 studied biologic scaffolds in animals, and 7 studied scaffolds or allografts in humans; the combined sample size was 202 patients. Of 4 histologic scaffold studies, 3 PRP-augmented scaffold studies identified histologic improvements in regenerated cartilage in animal models, while 1 BMC study demonstrated similar improvement in histologic scores of BMC-augmented scaffolds compared with controls. Three studies associated greater collagen type 2 and glycosaminoglycan content with PRP treatment. Comparative studies found that both augments increase osteogenic proteins, including bone morphogenetic protein–2 and osteoprotegerin. Two of 3 studies on BMC-augmented osteochondral allografts reported no difference in radiographic features postoperatively. Long-term improvement in clinical and radiographic outcomes of PRP-augmented scaffolds was demonstrated in 1 human study.

Conclusion:

Animal studies suggest that biologics possess potential as adjuncts to surgical treatment of osteochondral knee defects; however, clinical data remain limited.

Emerging and New Treatment Options for Knee Osteoarthritis

Osteoarthritis (OA) is the most prevalent type of arthritis worldwide, resulting in pain and often chronic disability and a significant burden on healthcare systems globally. Non-steroidal anti-inflammatory drugs (NSAIDs), analgesics, intra-articular corticosteroid injections are of little value in the long term, and opioids may have ominous consequences. Radiotherapy of knee OA has no added value. Physical therapy, exercises, weight loss, and lifestyle modifications may give pain relief, improve physical functioning and quality of life. However, no single treatment has regenerating potential for damaged articular cartilage. Due to a better understanding of osteoarthritis, innovative new treatment options have been developed. In this narrative review, we focus on emerging OA knee treatments, relieving symptoms, and regenerating damaged articular cartilage that includes intra-articular human serum albumin, conventional disease-modifying anti-rheumatic drugs (DMARDs), lipid-lowering agents (statin), nerve growth factors antagonists, bone morphogenetic protein, fibroblast growth factors, Platelet-Rich Plasma (PRP), Mesenchymal Stem Cells (MSC), exosomes, interleukin-1 blockers, gene-based therapy, and bisphosphonate.

Mesenchymal Stem Cells in the Treatment of Cartilage Defects of the Knee: A Systematic Review of the Clinical Outcomes

BACKGROUND

Osteochondral lesions are a common clinical problem and their management has been historically challenging. Mesenchymal stem cells have the potential to differentiate into chondrocytes and thus restore hyaline cartilage to the defect, theoretically improving clincal outcomes in these patients. They can also be harvested with minimal donor site morbidity.

PURPOSE

To assess the clinical and functional outcomes of mesenchymal stem cell implantation to treat isolated osteochondral defects of the knee. A secondary purpose is to assess the quality of the current available evidence as well as the radiological and histological outcomes. We also reviewed the cellular preparation and operative techniques for implantation.

STUDY DESIGN

Systematic review.

METHODS

A comprehensive literature search of 4 databases was carried out: CINAHL, Embase, MEDLINE, and PubMed. We searched for clinical studies reporting the outcomes on a minimum of 5 patients with at least 12 months of follow-up. Clinical, radiological, and histological outcomes were recorded. We also recorded demographics, stem cell source, culture technique, and operative technique. Methodological quality of each study was assessed using the modified Coleman methodology score, and risk of bias for the randomized controlled studies was assessed using the Cochrane Collaboration tool.

RESULTS

Seventeen studies were found, encompassing 367 patients. The mean patient age was 35.1 years. Bone marrow was the most common source of stem cells utilized. Mesenchymal stem cell therapy consistently demonstrated good short- to medium-term outcomes in the studies reviewed with no serious adverse events being recorded. There was significant heterogeneity in cell harvesting and preparation as well as in the reporting of outcomes.

CONCLUSION

Mesenchymal stem cells demonstrated a clinically relevant improvement in outcomes in patients with osteochondral defects of the knee. More research is needed to establish an optimal treatment protocol, long-term outcomes, and superiority over other therapies.

REGISTRATION

CRD42020179391 (PROSPERO).

A Systematic Review of Focal Cartilage Defect Treatments in Middle-Aged Versus Younger Patients

Background:

Focal cartilage defects are often debilitating, possess limited potential for regeneration, are associated with increased risk of osteoarthritis, and are predictive for total knee arthroplasty. Cartilage repair studies typically focus on the outcome in younger patients, but a high proportion of treated patients are 40 to 60 years of age (ie, middle-aged). The reality of current clinical practice is that the ideal patient for cartilage repair is not the typical patient. Specific attention to cartilage repair outcomes in middle-aged patients is warranted.

Purpose:

To systematically review available literature on knee cartilage repair in middle-aged patients and include studies comparing results across different age groups.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic search was performed in EMBASE, MEDLINE, and the Cochrane Library database. Articles were screened for relevance and appraised for quality.

Results:

A total of 21 articles (mean Coleman Methodology Score, 64 points) were included. Two out of 3 bone marrow stimulation (BMS) studies, including 1 using the microfracture technique, revealed inferior clinical outcomes in middle-aged patients in comparison with younger patients. Nine cell-based studies were included showing inconsistent comparisons of results across age groups for autologous chondrocyte implantation (ACI). Bone marrow aspirate concentrate showed age-independent results at up to 8 years of follow-up. A negative effect of middle age was reported in 1 study for both ACI and BMS. Four out of 5 studies on bone-based resurfacing therapies (allografting and focal knee resurfacing implants [FKRIs]) showed age-independent results up to 5 years. One study in only middle-aged patients reported better clinical outcomes for FKRIs when compared with biological repairs.

Conclusion:

Included studies were heterogeneous and had low methodological quality. BMS in middle-aged patients seems to only result in short-term improvements. More research is warranted to elucidate the ameliorating effects of cell-based therapies on the aging joint homeostasis. Bone-based therapies seem to be relatively insensitive to aging and may potentially result in effective joint preservation. Age subanalyses in cohort studies, randomized clinical trials, and international registries should generate more evidence for the large but underrepresented (in terms of cartilage repair) middle-aged population in the literature.

[Surgical treatment of focal cartilage defects in the knee : Indications, techniques, modifications and results]

The treatment strategies for focal cartilage damage in the knee are multifarious. For established procedures, such as microfracturing (MFX), autologous matrix-induced chondrogenesis (AMIC), osteochondral transplantation (OCT) and autologous chondrocyte transplantation (ACT), well-founded, partly comparative long-term studies and overlapping size-dependent differential indications are available. Innovative cell sources, the utilization of biological scaffolds as well as biologic agents and various combinations, have recently become the focus of scientific attention; however, high regulatory demands are restricting their use in Germany. The success of every procedure is dependent on the appropriate indications, the treatment of comorbidities, such as axis deviations or ligamentous instability, the surgeon's experience and an adequate follow-up treatment.

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.

Cell Sources for Cartilage Repair-Biological and Clinical Perspective

Cell-based therapy represents a promising treatment strategy for cartilage defects. Alone or in combination with scaffolds/biological signals, these strategies open many new avenues for cartilage tissue engineering. However, the choice of the optimal cell source is not that straightforward. Currently, various types of differentiated cells (articular and nasal chondrocytes) and stem cells (mesenchymal stem cells, induced pluripotent stem cells) are being researched to objectively assess their merits and disadvantages with respect to the ability to repair damaged articular cartilage. In this paper, we focus on the different cell types used in cartilage treatment, first from a biological scientist’s perspective and then from a clinician’s standpoint. We compare and analyze the advantages and disadvantages of these cell types and offer a potential outlook for future research and clinical application.

Technological Advances of 3D Scaffold-Based Stem Cell/Exosome Therapy in Tissues and Organs

Recently, biomaterial scaffolds have been widely applied in the field of tissue engineering and regenerative medicine. Due to different production methods, unique types of three-dimensional (3D) scaffolds can be fabricated to meet the structural characteristics of tissues and organs, and provide suitable 3D microenvironments. The therapeutic effects of stem cell (SC) therapy in tissues and organs are considerable and have attracted the attention of academic researchers worldwide. However, due to the limitations and challenges of SC therapy, exosome therapy can be used for basic research and clinical translation. The review briefly introduces the materials (nature or polymer), shapes (hydrogels, particles and porous solids) and fabrication methods (crosslinking or bioprinting) of 3D scaffolds, and describes the recent progress in SC/exosome therapy with 3D scaffolds over the past 5 years (2016-2020). Normal SC/exosome therapy can improve the structure and function of diseased and damaged tissues and organs. In addition, 3D scaffold-based SC/exosome therapy can significantly improve the structure and function cardiac and neural tissues for the treatment of various refractory diseases. Besides, exosome therapy has the same therapeutic effects as SC therapy but without the disadvantages. Hence, 3D scaffold therapy provides an alternative strategy for treatment of refractory and incurable diseases and has entered a transformation period from basic research into clinical translation as a viable therapeutic option in the future.

Efficacy and safety of mesenchymal stem cell injections for patients with osteoarthritis: a meta-analysis and review of RCTs

INTRODUCTION

Osteoarthritis (OA), which has a high incidence in the elderly, brings a huge economic burden to society. MSCs (Mesenchymal Stem Cells) have shown great multidirectional differentiation potential which are expected to treat OA, and numerous clinical trials have been conducted. However, the efficacy and safety of the MSCs still need to be further integrated and analyzed.

MATERIALS AND METHODS

We searched several databases (PubMed, EMBASE, Scopus, Web of Science, Cochrane Library, Ovid, and ScienceDirect) for assessing eligible trials that randomized controlled trials, hyaluronic acid as control, and MSCs injection to treat OA. Vitro studies and animal studies were excluded. Search terms were: "cartilage," "clinical trial," "mesenchymal," "stromal" and "stem cell", "osteoarthritis". The preliminary guidelines and study protocol were published online at PROSPERO.

RESULTS

Many assessment scales could not be improved significantly after 6 months. However, most of the scales were significantly improved after 12 months, indicating that compared with hyaluronic acid, stem cells could relieve OA symptoms significantly. No serious adverse effect was found.

CONCLUSION

There are significant therapeutic effects on joint function, symptoms, and no permanent adverse effect has been found after stem cell treatment. It is promising to apply intro-articular injection of stem cells for OA to clinical application. More researches are needed to supplement present deficiencies.

Scaffold With Natural Calcified Cartilage Zone for Osteochondral Defect Repair in Minipigs

BACKGROUND

Long-term outcomes of current clinical interventions for osteochondral defect are less than satisfactory. One possible reason is an ignorance of the interface structure between cartilage and subchondral bone, the calcified cartilage zone (CCZ). However, the importance of natural CCZ in osteochondral defects has not been directly described.

PURPOSE

To explore the feasibility of fabricating trilayer scaffold containing natural CCZ for osteochondral defects and the role of CCZ in the repair process.

STUDY DESIGN

Controlled laboratory study.

METHODS

The scaffold was prepared by cross-linking lyophilized type II collagen sponge and acellular normal pig subchondral bone with or without natural CCZ. Autologous bone marrow stem cells (BMSCs) of minipig were mixed with type II collagen gel and injected into the cartilage layer of the scaffold before operation. Thirty minipigs were randomly divided into CCZ (n = 10), non-CCZ (n = 10), and blank control (n = 10) groups. An 8 mm-diameter full-thickness osteochondral defect was created on the trochlear surface, and scaffold containing BMSCs was transplanted into the defect according to grouping requirements. At 12 and 24 weeks postoperatively, specimens were assessed by macroscopic observation, magnetic resonance imaging examination, and histological observations (hematoxylin and eosin, Safranin O-fast green, type II collagen immunohistochemical, and Sirius red staining). Semiquantitative cartilage repair scoring was conducted using the MOCART (Magnetic Resonance Observation of Cartilage Repair Tissue) system and the O'Driscoll repaired cartilage value system.

RESULTS

The defects in the blank control and non-CCZ groups were filled with fibrous tissue, while the cartilage layer of the CCZ group was mainly repaired by hyaline cartilage at 24 weeks postoperatively. The superior repair outcome of the CCZ group was confirmed by MOCART and O'Driscoll score.

CONCLUSION

The trilayer scaffold containing natural CCZ obtained the best repair effect compared with the non-CCZ scaffold and the blank control, indicating the importance of the CCZ in osteochondral tissue engineering.

CLINICAL RELEVANCE

This study demonstrates the necessity to reconstruct CCZ in clinical osteochondral defect repair and provides a possible strategy for osteochondral tissue engineering.

The development of natural polymer scaffold-based therapeutics for osteochondral repair

Due to the limited regenerative capacity of cartilage, untreated joint defects can advance to more extensive degenerative conditions such as osteoarthritis. While some biomaterial-based tissue-engineered scaffolds have shown promise in treating such defects, no scaffold has been widely accepted by clinicians to date. Multi-layered natural polymer scaffolds that mimic native osteochondral tissue and facilitate the regeneration of both articular cartilage (AC) and subchondral bone (SCB) in spatially distinct regions have recently entered clinical use, while the transient localized delivery of growth factors and even therapeutic genes has also been proposed to better regulate and promote new tissue formation. Furthermore, new manufacturing methods such as 3D bioprinting have made it possible to precisely tailor scaffold micro-architectures and/or to control the spatial deposition of cells in requisite layers of an implant. In this way, natural and synthetic polymers can be combined to yield bioactive, yet mechanically robust, cell-laden scaffolds suitable for the osteochondral environment. This mini-review discusses recent advances in scaffolds for osteochondral repair, with particular focus on the role of natural polymers in providing regenerative templates for treatment of both AC and SCB in articular joint defects.

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.

Bone Marrow Aspirate Concentrate Combined with in Situ Forming Bioresorbable Gel Enhances Intervertebral Disc Regeneration in Rabbits

BACKGROUND

The current surgical procedure of choice for intervertebral disc (IVD) herniation is discectomy, which induces postoperative IVD degeneration. Thus, cell-based therapies, as a 1-step simple procedure, are desired because of the poor capacity of IVDs for self-repair. The aim of this study was to investigate the repair efficacy of ultra-purified alginate (UPAL) gels containing bone marrow aspirate concentrate (BMAC) for the treatment of discectomy-associated IVD degeneration in rabbits.

METHODS

The mechanical properties of 3 types of gels-UPAL, UPAL containing bone marrow-derived mesenchymal stem cells (BMSCs), and UPAL containing BMAC-were evaluated. Forty rabbits were assigned to 5 groups: intact control, discectomy (to make the cavity), UPAL (implantation of the UPAL gel after discectomy), BMSCs-UPAL (implantation of a combination of autogenic BMSCs and UPAL gel after discectomy), and BMAC-UPAL (implantation of a combination of BMAC and UPAL gel after discectomy). The gels were implanted at 4 weeks after induction of IVD degeneration. At 4 and 12 weeks, magnetic resonance imaging (MRI) as well as histological and immunohistochemical analyses were performed to analyze IVD degeneration qualitatively and the viability of the implanted cells.

RESULTS

There was no significant difference among the 3 types of gels in terms of the results of unconfined compression tests. The implanted cells survived for 12 weeks. The histological grades of the BMSCs-UPAL (mean and standard deviation, 2.50 ± 0.53; p < 0.001) and BMAC-UPAL (2.75 ± 0.64, p = 0.001) showed them to be more effective in preventing degeneration than UPAL gel alone (3.63 ± 0.52). The effectiveness of BMAC-UPAL was not significantly different from that of BMSCs-UPAL, except with respect to type-II collagen synthesis.

CONCLUSIONS

BMAC-UPAL significantly enhanced the repair of IVD defects created by discectomy. This approach could be an effective therapeutic strategy owing to its simplicity and cost-effectiveness compared with cell therapy using culture-expanded BMSCs.

CLINICAL RELEVANCE

Local administration of the BMAC combined with UPAL gel could be an effective therapeutic strategy to enhance IVD repair after discectomy.

Role of Scaffolds, Subchondral, Intra-Articular Injections of Fresh Autologous Bone Marrow Concentrate Regenerative Cells in Treating Human Knee Cartilage Lesions: Different Approaches and Different Results

The value of bone marrow aspirate concentrates for treatment of human knee cartilage lesions is unclear. Most of the studies were performed with intra-articular injections. However, subchondral bone plays an important role in the progression of osteoarthritis. We investigated by a literature review whether joint, subchondral bone, or/and scaffolds implantation of fresh autologous bone marrow aspirate concentrated (BMAC) containing mesenchymal stem cells (MSCs) would improve osteoarthritis (OA). There is in vivo evidence that suggests that all these different approaches (intra-articular injections, subchondral implantation, scaffolds loaded with BMAC) can improve the patient. This review analyzes the evidence for each different approach to treat OA. We found that the use of intra-articular injections resulted in a significant relief of pain symptoms in the short term and was maintained in 12 months. However, the clinical trials indicate that the application of autologous bone marrow concentrates in combination with scaffolds or in injection in the subchondral bone was superior to intra-articular injection for long-term results. The tendency of MSCs to differentiate into fibrocartilage affecting the outcome was a common issue faced by all the studies when biopsies were performed, except for scaffolds implantation in which some hyaline cartilage was found. The review suggests also that both implantation of subchondral BMAC and scaffolds loaded with BMAC could reduce the need for further surgery.

Autologous Matrix-Induced Chondrogenesis for Treatment of Focal Cartilage Defects in the Knee: A Follow-up Study

Background:

Autologous matrix-induced chondrogenesis (AMIC) is a well-established treatment for full-thickness cartilage defects.

Purpose:

To evaluate the long-term clinical outcomes of AMIC for the treatment of chondral lesions of the knee.

Study Design:

Case series; Level of evidence, 4.

Methods:

A multisite prospective registry recorded demographic data and outcomes for patients who underwent repair of chondral defects. In total, 131 patients were included in the study. Lysholm, Knee injury and Osteoarthritis Outcome Score (KOOS), and visual analog scale (VAS) score for pain were used for outcome analysis. Across all patients, the mean ± SD age of patients was 36.6 ± 11.7 years. The mean body weight was 80.0 ± 16.8 kg, mean height was 176.3 ± 7.9 cm, and mean defect size was 3.3 ± 1.8 cm². Defects were classified as Outerbridge grade III or IV. A repeated-measures analysis of variance was used to compare outcomes across all time points.

Results:

The median follow-up time for the patients in this cohort was 4.56 ± 2.92 years. Significant improvement (P < .001) in all scores was observed at 1 to 2 years after AMIC, and improved values were noted up to 7 years postoperatively. Among all patients, the mean preoperative Lysholm score was 46.9 ± 19.6. At the 1-year follow-up, a significantly higher mean Lysholm score was noted, with maintenance of the favorable outcomes at 7-year follow-up. The KOOS also showed a significant improvement of postoperative values compared with preoperative data. The mean VAS had significantly decreased during the 7-year follow-up. Age, sex, and defect size did not have a significant effect on the outcomes.

Conclusion:

AMIC is an effective method of treating chondral defects of the knee and leads to reliably favorable results up to 7 years postoperatively.

Measuring Outcomes in Knee Articular Cartilage Pathology

Measuring outcomes following treatment of knee articular cartilage lesions is crucial to determine the natural history of disease and the efficacy of treatments. Outcome assessments for articular cartilage treatments can be clinical (based on failure, lack of healing, reoperation, need for arthroplasty), radiographic (X-ray, MRI), histologic, or patient reported and functional. The purpose of this review is to discuss the application and properties of patient-reported outcomes (PROs) with a focus on articular cartilage injuries and surgery in the knee. The most frequently used and validated PROs for knee articular cartilage studies include: the Knee injury and Osteoarthritis and Outcome Score, International Knee Documentation Committee Subjective Knee Form, and Lysholm score as knee-specific measures; the Marx Activity Rating Scale and Tegner Activity Scale as activity measures; and EQ-5D and SF-36/12 as generic quality-of-life measures. Incorporating these validated PROs in studies pertaining to knee articular cartilage lesions will allow researchers to fully capture clinically relevant outcomes that are most important to patients.

Mesenchymal Stem Cell Implantation in Knee Osteoarthritis: Midterm Outcomes and Survival Analysis in 467 Patients

Background

A cell-based tissue engineering approach that uses mesenchymal stem cells (MSCs) has addressed the issue of articular cartilage repair in knees with osteoarthritis (OA).

Purpose

To evaluate the midterm outcomes, analyze the survival rates, and identify the factors affecting the survival rate of MSC implantation to treat knee OA.

Study Design

Case series; Level of evidence, 4.

Methods

We retrospectively evaluated 467 patients (483 knees) who underwent MSC implantation on a fibrin glue scaffold for knee OA with a minimum 5-year follow-up. Clinical outcomes were determined based on the International Knee Documentation Committee (IKDC) and Tegner activity scale results measured preoperatively and during follow-up. Standard radiographs were evaluated using Kellgren-Lawrence grading. Statistical analyses were performed to determine the survival rate and the effect of different factors on the clinical outcomes.

Results

The mean IKDC scores (baseline, 39.2 ± 7.2; 1 year, 66.6 ± 9.6; 3 years, 67.2 ± 9.9; 5 years, 66.1 ± 9.7; 9 years, 62.8 ± 8.5) and Tegner scores (baseline, 2.3 ± 1.0; 1 year, 3.4 ± 0.9; 3 years, 3.5 ± 0.9; 5 years, 3.4 ± 0.9; 9 years, 3.2 ± 0.9) were significantly improved until 3 years postoperatively and gradually decreased from 3- to 9-year follow-up (P < .05 for all, except for Tegner score at 5 years vs 1 year [P = .237]). Gradual deterioration of radiological outcomes according to the Kellgren-Lawrence grade was found during follow-up. Survival rates based on either a decrease in IKDC or an advancement of radiographic OA with Kellgren-Lawrence scores were 99.8%, 94.5%, and 74.5% at 5, 7, and 9 years, respectively. Based on multivariate analyses, older age and the presence of bipolar kissing lesion were associated with significantly worse outcomes (P = .002 and .013, respectively), and a larger number of MSCs was associated with significantly better outcomes (P < .001) after MSC implantation.

Conclusion

MSC implantation provided encouraging outcomes with acceptable duration of symptom relief at midterm follow-up in patients with early knee OA. Patient age, presence of bipolar kissing lesion, and number of MSCs were independent factors associated with failure of MSC implantation.

Fabrication of Silk-Hyaluronan Composite as a Potential Scaffold for Tissue Repair

Interest is rapidly growing in the design and preparation of bioactive scaffolds, mimicking the biochemical composition and physical microstructure for tissue repair. In this study, a biomimetic biomaterial with nanofibrous architecture composed of silk fibroin and hyaluronic acid (HA) was prepared. Silk fibroin nanofiber was firstly assembled in water and then used as the nanostructural cue; after blending with hyaluronan (silk:HA = 10:1) and the process of freeze-drying, the resulting composite scaffolds exhibited a desirable 3D porous structure and specific nanofiber features. These scaffolds were very porous with the porosity up to 99%. The mean compressive modulus of silk-HA scaffolds with HA MW of 0.6, 1.6, and 2.6 × 10⁶ Da was about 28.3, 30.2, and 29.8 kPa, respectively, all these values were much higher than that of pure silk scaffold (27.5 kPa). This scaffold showed good biocompatibility with bone marrow mesenchymal stem cells, and it enhanced the cellular proliferation significantly when compared with the plain silk fibroin. Collectively, the silk-hyaluronan composite scaffold with a nanofibrous structure and good biocompatibility was successfully prepared, which deserved further exploration as a biomimetic platform for mesenchymal stem cell-based therapy for tissue repair.