Nomenclature Inconsistency and Selective Outcome Reporting Hinder Understanding of Stem Cell Therapy for the Knee

Assessing the degree to which randomized controlled trials align with the core outcome set for osteoarthritis of knee and hip: A cross-sectional analysis

OBJECTIVE

To assess the degree of core outcome set alignment and identify issues with alignment to the 2019 COS among clinical trial registrations focused on knee and/or hip osteoarthritis (OA).

METHODS

Our search was performed on registered knee and hip OA randomized controlled trials (RCTs) available on ClinicalTrials.gov and WHO International Clinical Trials Registry Platform. The screening process considered trials registered between 8/2014 and 6/2023. We extracted data on general trial characteristics and the five trial endpoints detailed in the COS (pain, physical function, quality of life, patient global assessment, and adverse events), in a masked and duplicate manner. The frequencies of COS alignment were assessed over time prior to and after COS publication.

RESULTS

Of the 10,718 RCTs screened, 481 met inclusion criteria. Most were phase 3 (368/481, 76.51%) and heavily university-funded (184/481, 38.25%). Despite the 2019 COS, no marked enhancement in overall alignment was noted. The outcome 'Pain' exhibited the highest degree of COS alignment (455/481, 94.59%), whereas 'adverse events' lagged behind (89/481, 18.50%). Additionally, trial factors such as 'Continent', 'Funding Type', and 'Recruitment Status' displayed no significant influence on COS alignment.

CONCLUSIONS

Despite the acknowledged advantages of using COS in RCTs and the availability of an updated COS, the alignment to these outcomes remains notably low. Significant efforts are needed to encourage broader adoption in future studies on knee and hip OA, with the aim of improving research quality and patient care.

Taking a chance on outcome standardisation: A cross-sectional analysis assessing the uptake of the prevention of preterm birth core outcome set in randomised controlled trials

OBJECTIVE

Analyse uptake of the core outcome set (COS) within preterm birth (PTB) clinical trials.

DESIGN

On 26 June 2023, we conducted a systematic search of phase III/IV trial registry entries regarding PTB interventions via ClinicalTrials.gov and the International Clinical Trial Registry Platform. These trials were analysed for the outcomes measured.

SETTING

N/A.

SAMPLE

After searching the two databases, 5257 randomised controlled trials (RCTs) were screened, resulting in 92 RCTs for analysis.

METHODS

Inclusion criteria were the following: subjects were patients receiving an intervention for PTB, study enrolment began within 5 years prior to publication of PTB COS to 26 June 2023, and evaluated the efficacy of interventions. Authors screened and extracted data in masked, duplicate fashion, then performed an interrupted time series analysis, analysis of variance and correlation analysis.

MAIN OUTCOME MEASURES

We extracted outcomes measured by each clinical trial in our sample. Trials were analysed for the percentage of adopted outcomes from PTB COS.

RESULTS

After COS publication, there was no significant change in percentage of COS outcomes measured. The most measured outcome was 'offspring mortality' (54.34%, 50/92) and the least measured outcome was 'late neonatal neurodevelopment morbidity' (3.26%, 3/92). Additionally, 22.83% (21/92) of trials measured zero outcomes related to the PTB COS.

CONCLUSION

Our results demonstrated no significant change in outcome measurement before or after PTB COS publication. We recommend focusing on both the measurement of outcomes and the assessments that are used.

Intra-articular delivery of micronized dehydrated human amnion/chorion membrane reduces degenerative changes after onset of post-traumatic osteoarthritis

Background: Micronized dehydrated human amnion/chorion membrane (mdHACM) has reduced short term post-traumatic osteoarthritis (PTOA) progression in rats when delivered 24 h after medial meniscal transection (MMT) and is being investigated for clinical use as a disease modifying therapy. Much remains to be assessed, including its potential for longer-term therapeutic benefit and treatment effects after onset of joint degeneration. Objectives: Characterize longer-term effects of acute treatment with mdHACM and determine whether treatment administered to joints with established PTOA could slow or reverse degeneration. Hypotheses: Acute treatment effects will be sustained for 6 weeks, and delivery of mdHACM after onset of joint degeneration will attenuate structural osteoarthritic changes. Methods: Rats underwent MMT or sham surgery (left leg). mdHACM was delivered intra-articularly 24 h or 3 weeks post-surgery (n = 5-7 per group). Six weeks post-surgery, animals were euthanized and left tibiae scanned using equilibrium partitioning of an ionic contrast agent microcomputed tomography (EPIC-µCT) to structurally quantify joint degeneration. Histology was performed to examine tibial plateau cartilage. Results: Quantitative 3D µCT showed that cartilage structural metrics (thickness, X-ray attenuation, surface roughness, exposed bone area) for delayed mdHACM treatment limbs were significantly improved over saline treatment and not significantly different from shams. Subchondral bone mineral density and thickness for the delayed treatment group were significantly improved over acute treated, and subchondral bone thickness was not significantly different from sham. Marginal osteophyte degenerative changes were decreased with delayed mdHACM treatment compared to saline. Acute treatment (24 h post-surgery) did not reduce longer-term joint tissue degeneration compared to saline. Histology supported µCT findings and further revealed that while delayed treatment reduced cartilage damage, chondrocytes displayed qualitatively different morphologies and density compared to sham. Conclusion: This study provides insight into effects of intra-articular delivery timing relative to PTOA progression and the duration of therapeutic benefit of mdHACM. Results suggest that mdHACM injection into already osteoarthritic joints can improve joint health, but a single, acute mdHACM injection post-injury does not prevent long term osteoarthritis associated with meniscal instability. Further work is needed to fully characterize the durability of therapeutic benefit in stable osteoarthritic joints and the effects of repeated injections.

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.

Expanded Mesenchymal Stromal Cells in knee osteoarthritis: A systematic literature review

OBJECTIVE

To analyse the efficacy and safety of intra-articular injection of expanded Mesenchymal Stromal Cells (MSCs) in knee osteoarthritis.

METHODS

Systematic Literature Review. A pre-defined search strategy was run in Medline, Embase and Cochrane Library until February 2018.

INCLUSION CRITERIA

knee osteoarthritis (grades II-IV Kellgren-Lawrence); intra-articular injection of MSCs (without surgical co-treatments); Randomized Controlled Trials (RCTs) or Quasi-experimental Clinical Trials (QCTs) N ≥ 10 and ≥6 months of follow-up were included. Evidence was assigned according to the Scottish Intercollegiate Guidelines Network (SIGN).

RESULTS

The search identified 252 articles. Nine proof-of-concept trials (3 RCTs, 6 QCTs) were included (N = 169). Evidence showed clinical improvement in 60% of patients. Structural benefit was reported in half of patients. Clinical benefit was observed from the 3^rd month and structural improvement from the 6^th. All studies reported maximum clinical and structural benefit a year following the implant. This benefit was sustained for up to 24 months. Studies with doses ≥40 × 10⁶ showed more consistent clinical and structural benefits than those with lower doses. No systemic adverse reactions were reported. The most common adverse effect was pain and/or inflammation in the puncture area (13-53%). The use of donor cells was as safe as autologous implants.

CONCLUSIONS

Intra-articular implants of MSCs seem to be safe with no serious adverse effects. Low-quality evidence precludes conclusions regarding efficacy in this review. However, the clinical and structural benefits observed provide a rationale for using expanded MSCs implants in osteoarthritis patients. High-quality evidence trials are needed to further determine best protocols to maximize clinical and structural improvement.

Food and Drug Administration's Position on Commonly Injected Biologic Materials in Orthopaedic Surgery

The use of biologically based therapies is becoming a popular less-invasive therapy for relieving pain and promoting tissue regeneration. The most commonly used biologics are autologous adipose-derived products, bone marrow aspirations, and platelet-rich plasma (PRP). Birth tissue is a common allogenic source of biologics, including umbilical cord, placental membranes, and amniotic fluid. Injected biologics, depending on the indication and how they are processed, formulated, delivered, and promoted, can be subject to different regulatory pathways. The aim of this review is to provide an overview of these products and procedures and educate the musculoskeletal community about the relevant current Food and Drug Administration (FDA) regulations.

Editorial Commentary: Stem Cell Therapy for the Knee: Heterogeneity in Cell Sources, Delivery Methods, and Concomitant Surgery Needs to Be Considered

Mesenchymal stem cells (MSCs) have been investigated for the treatment of knee osteoarthritis because of their unique properties, including self-renewal, multi-linear cellular differentiation, and immunomodulatory capacity. However, the efficacy of MSCs for positive clinical outcomes in the treatment of knee osteoarthritis remains controversial. Because clinical studies in general have high variability, the heterogeneity in the sources of the stem cells used, efficacy of delivery methods, and concomitant surgery should be carefully considered to interpret the benefits of MSC therapy for knee osteoarthritis.

Expanded Mesenchymal Stromal Cells in Knee Osteoarthritis: A Systematic Literature Review

OBJECTIVE

To analyse the efficacy and safety of intra-articular injection of expanded Mesenchymal Stromal Cells (MSCs) in knee osteoarthritis.

METHODS

Systematic Literature Review. A pre-defined search strategy was run in Medline, Embase and Cochrane Library until February 2018.

INCLUSION CRITERIA

knee osteoarthritis (grades II-IV Kellgren-Lawrence); intra-articular injection of MSCs (without surgical co-treatments); Randomized Controlled Trials (RCTs) or Quasi-experimental Clinical Trials (QCTs) N≥10 and ≥6 months of follow-up were included. Evidence was assigned according to the Scottish Intercollegiate Guidelines Network (SIGN).

RESULTS

The search identified 252 articles. Nine proof-of-concept trials (3 RCTs, 6 QCTs) were included (N=169). Evidence showed clinical improvement in 60% of patients. Structural benefit was reported in half of patients. Clinical benefit was observed from the 3rd month and structural improvement from the 6th. All studies reported maximum clinical and structural benefit a year following the implant. This benefit was sustained for up to 24 months. Studies with doses ≥40×106 showed more consistent clinical and structural benefits than those with lower doses. No systemic adverse reactions were reported. The most common adverse effect was pain and/or inflammation in the puncture area (13-53%). The use of donor cells was as safe as autologous implants.

CONCLUSIONS

Intra-articular implants of MSCs seem to be safe with no serious adverse effects. Low-quality evidence precludes conclusions regarding efficacy in this review. However, the clinical and structural benefits observed provide a rationale for using expanded MSCs implants in osteoarthritis patients. High-quality evidence trials are needed to further determine best protocols to maximize clinical and structural improvement.

Effect of Stem Cell Injections on Osteoarthritis-related Structural Outcomes: A Systematic Review

OBJECTIVE

To systematically review the evidence for the efficacy of mesenchymal stem cell (MSC) injections in improving osteoarthritis (OA)-related structural outcomes.

METHODS

Ovid Medline and EMBASE were searched from their inceptions to April 2020 using MeSH terms and key words. Independent reviewers extracted data and assessed methodological quality. Qualitative evidence synthesis was performed due to the heterogeneity of interventions and outcome measures.

RESULTS

Thirteen randomized controlled trials (phase I or II) were identified: 10 in OA populations and 3 in populations at risk of OA, with low (n = 9), moderate (n = 3), or high (n = 1) risk of bias. Seven studies used allogeneic MSCs (4 bone marrow, 1 umbilical cord, 1 placenta, 1 adipose tissue), 6 studies used autologous MSCs (3 adipose tissue, 2 bone marrow, 1 peripheral blood). Among the 11 studies examining cartilage outcomes, 10 found a benefit of MSCs on cartilage volume, morphology, quality, regeneration, and repair, assessed by magnetic resonance imaging, arthroscopy, or histology. The evidence for subchondral bone was consistent in all 3 studies in populations at risk of OA, showing beneficial effects. Sixteen unpublished, eligible trials were identified by searching trial registries, including 8 with actual or estimated completion dates before 2016.

CONCLUSION

Our systematic review of early-phase clinical trials demonstrated consistent evidence of a beneficial effect of intraarticular MSC injections on articular cartilage and subchondral bone. Due to the heterogeneity of MSCs, modest sample sizes, methodological limitations, and potential for publication bias, further work is needed before this therapy is recommended in the management of OA.

Governmental Regulations and Increasing Food and Drug Administration Oversight of Regenerative Medicine Products: What's New in 2020?

The United States Food and Drug Administration (FDA) is responsible for protecting and promoting public health through rules and regulations. Over the past few years, the field of regenerative medicine and cell therapy have garnered significant interest, and this evolving new biology is changing fast and challenging regulatory bodies. The FDA has published a series of guidance documents outlining steps to protect consumers against potentially dangerous and unproven treatments. The agency has offered a grace period for "stem cell clinics" until November 2020 to come into compliance by obtaining Investigational New Drug applications and working to secure premarket approval of their products. With the documentation of hundreds of "stem cell clinics," the FDA needs to enforce the adherence to their outlined standards to protect patients. The aim of this review was to provide an overview of these FDA regulations and some current issues within the industry. The purpose is to educate and inform the musculoskeletal community about the current government regulations of this new expanding biology. LEVEL OF EVIDENCE: Level V, expert opinion.

Intra-articular Injection of Culture-Expanded Mesenchymal Stem Cells Without Adjuvant Surgery in Knee Osteoarthritis: A Systematic Review and Meta-analysis

BACKGROUND

Although many clinical studies have assessed the efficacy of mesenchymal stem cells (MSCs) in knee osteoarthritis, evidence on their efficacy remains unclear owing to heterogeneity of cell entity and concomitant procedures.

PURPOSE

To determine the efficacy of culture-expanded MSCs in knee osteoarthritis in terms of clinical outcome and cartilage repair via meta-analysis of randomized controlled trials (RCTs) without adjuvant surgery.

STUDY DESIGN

Meta-analysis.

METHODS

PubMed, Embase, the Cochrane Library, CINAHL, and Scopus were searched from inception to December 31, 2018. RCTs with culture-expanded MSCs for treating knee osteoarthritis were included. Studies with adjuvant surgery or cell concentrate were excluded. Quality was assessed by the Cochrane Collaboration risk-of-bias tool. For meta-analysis, data on clinical outcomes were measured using a visual analog scale (VAS) and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and data on cartilage repair were measured using the Whole-Organ Magnetic Resonance Imaging Score (WORMS); categorization related to improvement was extracted.

RESULTS

Six RCTs (203 patients) were included. Two studies were deemed to have a low risk of bias. In pooled analysis, the only significant difference was in the VAS score (mean difference, -13.55; 95% CI, -22.19 to -4.9). In cumulative pain analysis with VAS and WOMAC pain scores, there was significant improvement after treatment (standardized mean difference, -0.54; 95% CI, -0.85 to -0.23). There was no significant difference in cartilage repair assessed by magnetic resonance imaging (standardized mean difference, 0.11; 95% CI, -0.51 to 0.73), WORMS (standardized mean difference, 1.68; 95% CI -14.84 to 18.21), or categorical results (odds ratio, 1.56; 95% CI, 0.32-7.59).

CONCLUSION

Intra-articular injection of culture-expanded MSCs without adjuvant surgery can improve pain for patients experiencing knee osteoarthritis at short-term follow-up (6-12 months). However, evidence regarding function and cartilage repair remains limited.

Meniscal substitution, a developing and long-awaited demand

The menisci represent indispensable intraarticular components of a well-functioning knee joint. Sports activities, traumatic incidents, or simply degenerative conditions can cause meniscal injuries, which often require surgical intervention. Efforts in biomechanical and clinical research have led to the recommendation of a meniscus-preserving rather than a meniscus-resecting treatment approach. Nevertheless, partial or even total meniscal resection is sometimes inevitable. In such circumstances, techniques of meniscal substitution are required. Autologous, allogenic, and artificial meniscal substitutes are available which have evolved in recent years. Basic anatomical and biomechanical knowledge, clinical application, radiological and clinical outcomes as well as future perspectives of meniscal substitutes are presented in this article. A comprehensive knowledge of the different approaches to meniscal substitution is required in order to integrate these evolving techniques in daily clinical practice to prevent the devastating effects of lost meniscal tissue.

Intra-articular treatment options for knee osteoarthritis

Intra-articular drug delivery has a number of advantages over systemic administration; however, for the past 20 years, intra-articular treatment options for the management of knee osteoarthritis (OA) have been limited to analgesics, glucocorticoids, hyaluronic acid (HA) and a small number of unproven alternative therapies. Although HA and glucocorticoids can provide clinically meaningful benefits to an appreciable number of patients, emerging evidence indicates that the apparent effectiveness of these treatments is largely a result of other factors, including the placebo effect. Biologic drugs that target inflammatory processes are used to manage rheumatoid arthritis, but have not translated well into use in OA. A lack of high-level evidence and methodological limitations hinder our understanding of so-called 'stem' cell therapies and, although the off-label administration of intra-articular cell therapies (such as platelet-rich plasma and bone marrow aspirate concentrate) is common, high-quality clinical data are needed before these treatments can be recommended. A number of promising intra-articular treatments are currently in clinical development in the United States, including small-molecule and biologic therapies, devices and gene therapies. Although the prospect of new, non-surgical treatments for OA is exciting, the benefits of new treatments must be carefully weighed against their costs and potential risks.

Online Direct-to-Consumer Advertising of Stem Cell Therapy for Musculoskeletal Injury and Disease: Misinformation and Violation of Ethical and Legal Advertising Parameters

BACKGROUND

There has been a recent surge in health-care providers offering stem cell therapy (SCT) to patients with musculoskeletal disease. The purpose of this study was to identify and quantify the misinformation present in online direct-to-consumer (DTC) advertising of SCT targeting patients with musculoskeletal disease in the U.S. It was hypothesized that DTC advertising of SCT contains substantial misinformation.

METHODS

A list of keywords was used to identify web sites of practices advertising SCT directly to patients with musculoskeletal disease. Web sites were evaluated to determine the specialties of providers offering SCT, types of SCT being advertised, and misinformation presented. Categories of misinformation included false general claims, inaccurate statements regarding mechanism of action, unfounded results, and scare tactics.

RESULTS

Of the 896 practice web sites included in the analysis, 95.9% contained at least 1 statement of misinformation, with a mean of 4.65 ± 3.66 statements of misinformation among the sites. Practices associated with an orthopaedic surgeon provided 22% fewer statements of misinformation than practices without an orthopaedic surgeon when we controlled for the effects of other specialties. Practices associated with a podiatrist also provided 22% fewer statements of misinformation.

CONCLUSIONS

Nearly all practices failed to accurately represent the clinical efficacy of SCT in DTC advertising. While practices associated with an orthopaedic surgeon were less likely to provide misinformation, the majority of all web sites contained some type of misinformation, ranging from errors in the basic science of stem cells to outright false and misleading claims of their clinical effectiveness.

Bone Marrow Mesenchymal Stem Cell Therapy and Related Bone Marrow-Derived Orthobiologic Therapeutics

PURPOSE OF REVIEW

The purpose of the current article is to review the available literature related to bone marrow-derived mesenchymal stem cell therapy in the management of musculoskeletal pathologies and demonstrate the critical need for additional well-designed clinical studies.

RECENT FINDINGS

In recent years, there has been a rapid increase in interest regarding the use of bone marrow-derived mesenchymal stem cells in the treatment of musculoskeletal injury and disease. The clinical use of BM-MSCs and other forms of stem cell therapy has far outpaced the basic and translational science evidence required to elucidate the potential efficacy of this orthobiologic treatment approach. Early studies have demonstrated potential clinical benefit of utilizing bone marrow-derived mesenchymal stem cell therapy in the management of knee osteoarthritis, focal chondral lesions, shoulder pathology including rotator cuff tears and glenohumeral arthritis, and degenerative disk disease in the spine. To date, most published studies are small case series often lacking a control group or a standardized method of treatment. Bone marrow-derived mesenchymal stem cell therapy is becoming an increasingly common treatment for musculoskeletal injuries and disease. Although early clinical studies have shown promising outcomes, methodological flaws and lack of standardization among trials have limited the conclusions that can be drawn from the existing literature. A better understanding of the underlying mechanism of action and more carefully designed clinical trials will help reveal the efficacy and utility of BM-MSCs as a treatment modality for various orthopedic pathologies.

The role of biologic agents in the management of common shoulder pathologies: current state and future directions

The field of orthopedic surgery has seen a rapid increase in the use of various biologic agents for the treatment of common musculoskeletal injuries. Most biologic agents attempt to harness or mimic naturally occurring growth factors, cytokines, and anti-inflammatory mediators to improve tissue healing and recovery. The most commonly used biologic agents are platelet-rich plasma and cells derived from bone marrow aspirate and adipose tissue. These agents have become increasingly popular despite a relative dearth of clinical data to support their use. Much confusion exists among patients and physicians in determining the role of these agents in treating common shoulder pathologies, such as glenohumeral osteoarthritis, rotator cuff tears, and tendinopathy. This article reviews the basic science and clinical evidence for the most commonly used biologic agents in the management of common shoulder pathology.

In Vitro Targeting and Imaging of Neurogenic Differentiation in Mouse Bone-Marrow Derived Mesenchymal Stem Cells with Superparamagnetic Iron Oxide Nanoparticles

Spinal cord injuries (SCI) are well thought to be a crucial issue that roots various side effects for a patient during their entire lifetime. Although therapeutical methods to resolve the SCI are limited, stem cell therapy is determined to be a resolving factor since it possesses the ability to induce the neurogenic differentiation and the paracrine effect. However, stem cells are difficult to inject directly into the lesion, so they must be carefully guided through the spinal canal. Therefore, superparamagnetic iron oxide nanoparticles (SPIONs) are introduced as an instigator that makes the cells respond to the applied magnetic field. This study intends to report the synthesis strategy to develop SPIONs that could be used to treat the injury site by an applied magnetic field. SPION-internalized D1 Mesenchymal stem cells (MSCs) are observed consistently using a confocal fluorescence microscope to analyze the toxicity, maintenance, and monitoring points of intracellular SPIONs. The prepared SPIONs are much anticipated to increase the migration efficiency using magnetism, which was not cytotoxic. Hence, the prepared SPIONs can adeptly target the damaged neural tissue to promote tissue regeneration and treat nervous system disorders. This primary study stands as a focal point to solve SCI by stem cell migration effectively.

Editorial Commentary: Considering Clinical Application of Bone Marrow Aspirate Concentrate for Restoration of Cartilage Defects in the Knee? Is It a Kind of Stem Cell Therapy?

The role of bone marrow aspirate concentrate (BMAC) is still inconclusive for restoration of chondral defects in lesions of the knee. More investigation is needed; thus, clinical application of BMAC for chondral defects should be considered cautiously. Correct nomenclature of the entity of cells used in various stem cell therapies for the treatment of cartilage lesions is critical to properly assess the efficacy and safety of various stem cell therapies. Constant effort is needed to prove the therapeutic potential of various novel therapeutic options such as BMAC or stem cell therapy under correct terminology for cartilage restoration before routine clinical application.