High Variability in Return-to-Sport Assessment After Autologous Chondrocyte Implantation of the Knee: A Systematic Review

Abstract

Purpose

To systematically review return-to-sport (RTS) patient-reported outcome measure (PROM) usage following autologous chondrocyte implantation (ACI) and matrix-induced autologous chondrocyte implantation (MACI). We hypothesized that RTS reporting would be highly inconsistent, limiting clinical applicability.

Methods

A systematic review was conducted using PubMed, Embase, and Scopus (January 1, 2014–December 8, 2024). Eligible studies reported RTS PROMs after ACI/MACI. Extracted data included study design, demographics, name and type of scale used, and assessment modality.

Results

Of 807 studies screened, 85 met inclusion criteria. Measures used to report RTS varied widely. The Knee injury and Osteoarthritis Outcome Score–Sport/Rec and the International Knee Documentation Committee Subjective Knee Evaluation Form were the most commonly reported validated PROMs, included in 71.8% and 49.4% of studies, respectively. Only 15.3% of studies reported RTS as a postoperative percentage. Of all, 22.4% of studies used custom, nonvalidated tools. Most studies (49.4%) were prospective, and in-person evaluation was most common (52.8%). Timepoints of RTS measurement were inconsistent.

Conclusions

RTS is inconsistently quantified following ACI/MACI, limiting cross-study comparisons and complicating clinical interpretation of outcomes. Standardized use of and expansion of validated PROMs is needed to improve the clinical applicability of data on RTS for ACI/MACI

Keywords

return to sport MACI ACI autologous chondrocyte implantation matrix-induced autologous chondrocyte implantation RTS KOOS-S/R IKDC PROMs patient-reported outcome measures cartilage restoration

Introduction

Articular cartilage defects of the knee represent a challenging clinical problem, especially in young and active individuals. If left untreated, these lesions can lead to persistent pain, functional impairment, and an increased risk for early-onset osteoarthritis.^1
-3 Autologous chondrocyte implantation (ACI) and its next-generation counterpart, matrix-induced autologous chondrocyte implantation (MACI), are among the most commonly performed restorative techniques for full-thickness chondral defects.⁴ These cell-based restoration procedures aim to regenerate cartilage in the knee and offer promising long-term outcomes.^5,6

Return to sport (RTS) after ACI and MACI has emerged as a key metric of success for both patients and physicians, especially given the procedures’ relevance for young, active individuals with knee cartilage defects.^7
-10 The ability to return to pre-injury levels of physical activity and mobility is often the primary motivation for undergoing ACI/MACI, especially among athletes.¹⁰

Validated patient-reported outcome measures (PROMs), such as the Knee Injury and Osteoarthritis Outcome Score—Sport and Recreation subscale (KOOS-S/R) and the International Knee Documentation Committee (IKDC), have become commonly utilized for assessing knee pain and function.^11,12 However, the use of specific PROMs to assess RTS following ACI/MACI is varied, likely due to differences in patient demographics, surgical technique, rehabilitation procedures, and, most relevantly, the assessment methods used to define RTS in patients.^9,13,14 Despite its clinical importance, RTS is often vaguely reported in the literature, using a wide range of assessment methods—from custom, nonvalidated tools to standardized, validated measures.

This considerable variability in RTS measurement affects how outcomes are reported; for instance, RTS rates following ACI and MACI range broadly from 54% to over 80% and are assessed at widely varying postoperative timepoints, making it difficult to confidently compare recovery outcomes and timelines.^15,16 This mirrors concerns raised in anterior cruciate ligament reconstruction literature, where high variability in outcome reporting has led to significant challenges in comparing results and outcomes across studies to guide patient expectations.¹⁷

Given the importance of RTS in clinical decision-making, especially among athletic populations, understanding how RTS is defined and measured following ACI and MACI is paramount.¹⁸ Clearer definitions and standardized assessment tools allow for more meaningful comparisons across studies, even aiding in establishing benchmarks for clinical success of the procedure. Therefore, the purpose of this study was to systematically review the current literature on RTS following two-stage cell expansion cartilage repair (i.e., ACI and MACI), critically evaluate the definitions and assessment tools used, and identify the degree of variability present. We hypothesized that methodologies used to define and assess RTS following ACI and MACI procedures would be highly variable across studies. This inconsistency may limit the clinical utility of existing literature in establishing standardized rehabilitation protocols and setting appropriate expectations for patients undergoing cartilage restoration. However, there is a paucity in the literature evaluating RTS methodology following knee cartilage–restoration procedures. As such, this study sought to systematically characterize variability in RTS assessment methodology across a large body of MACI/ACI literature. Findings from this review may help inform more consistent RTS reporting practices in future studies and contribute to the development of clearer clinical guidelines for postoperative counseling and RTS planning.

Methods

This review was guided by the Population, Intervention, Comparison, and Outcome (PICO) framework.¹⁹ The population included patients who underwent two-stage cell-expansion cartilage-restoration procedures of the knee, specifically ACI and/or MACI. The intervention of interest was RTS assessment following ACI/MACI. Given the descriptive nature of our synthesis, a formal comparison group was not included. The primary outcome was how RTS was assessed across studies, including the use of validated PROMs, custom assessments, and reported RTS rates.

In this review, we included studies on both ACI and MACI, the latter of which is considered a third-generation, scaffold-based refinement of ACI. Given their shared two-stage design and biologic principles, we grouped ACI and MACI for the purpose of evaluating RTS-reporting methodology, rather than comparing clinical outcomes between the two.

A systematic review was performed to evaluate how RTS following ACI and MACI procedures is defined and assessed in the existing literature. The methodology was developed in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA guidelines; Fig. 1 ). Comprehensive searches of PubMed, Embase, and Scopus were conducted from January 1, 2014, through December 8, 2024, using the relevant keywords: “MACI,” “ACI,” or “matrix-induced autologous chondrocyte implantation” and “sport,” “play,” or “physical activity.” References of included articles were also reviewed to identify any additional relevant studies. The abstracts of identified studies were assessed independently by two reviewers (R.S., S.d.) for inclusion. Any conflicts in inclusion decisions were resolved by consensus between the primary and secondary authors (C.V., M.K). Abstracts selected for inclusion then underwent full-text screening for relevance by two independent raters, with discrepancies again resolved by the primary and secondary authors. Studies meeting inclusion criteria were subsequently extracted for analysis.

Figure 1.

PRISMA flow diagram illustrating the study-selection process. A total of 807 studies were identified across PubMed, Scopus, and Embase. After removal of 259 duplicates, 548 studies were screened. Of these, 157 were sought for full-text retrieval, and 72 were excluded for reasons including lack of full text, publication prior to 2014, not analyzing ACI/MACI, or not assessing postoperative RTS. A total of 85 studies met inclusion criteria and were included in the final review. MACI = matrix-induced autologous chondrocyte implantation; ACI = autologous chondrocyte implantation; RTS = return to sports.

Studies were eligible for inclusion if they reported RTS outcomes following ACI or MACI as a primary or secondary endpoint and defined how RTS was measured or evaluated. All original clinical research articles were considered, including retrospective and prospective cohort studies and randomized controlled trials. Exclusion criteria included reviews, case reports, surgical technique articles, conference abstracts, and those lacking an explicit RTS assessment. In addition, we excluded mixed-cell implants and combined or hybrid procedures. Studies with scales that included a sports-specific subscale were only included if the relevant subscale results were delineated in a table.

Data extracted from each study included study design, country of origin, year of publication, sample size, patient age group, type of procedure (ACI or MACI), and RTS-related metrics. Specific RTS-related variables included the assessment method used (percentage or number of subjects returning to sport at one or more given time points, the use of validated sports-specific PROM scales or subscales, or the use of custom sports-specific PROMs), the modality of questionnaire delivery, and time points of assessment.

RTS assessment methods were recorded by examining the Results, Tables, and Figures sections of included studies. When PROMs were used to assess RTS, they were recorded in detail, in accordance with the data-extraction criteria above. The validated PROMs identified across the included studies were: the KOOS-S/R, IKDC, the Tegner Activity Scale, the Lysholm Knee Scoring Scale, the Cincinnati Sports Activity Scale (CSAS), and the Noyes Sports Activity Rating Scale (NSARS). Because of the substantial heterogeneity in how RTS was defined and measured, results were synthesized descriptively.

Statistical Analysis

Descriptive statistics were used to summarize study characteristics, including procedure type, study type, patient age group, and country of origin ( Table 1 ). Categorical variables were reported as counts and percentages. Frequency distributions were used to identify the most commonly used PROM instruments (such as KOOS-S/R, IKDC, Lysholm, and Tegner Activity Scale), level of evidence (LOE), modality of assessment, year of publication, and timepoints of PROM administration. Due to the heterogeneity in RTS definitions, assessment time points, and outcome-reporting formats, no meta-analysis or pooled comparative statistics were performed.

Table 1.

Included Studies Evaluated RTS in ACI (n = 51, 60.0%) and MACI (n = 36, 42.4%).

Demographic	Number of Studies (%)
Procedure type
ACI	48 (56.5)
MACI	33 (38.8)
Both (ACI and MACI)	3 (3.5)
Study type
Retrospective	28 (32.9)
Prospective	42 (49.4)
Randomized controlled trial	15 (17.6)
Patient age group ^a
Adult	28 (32.9)
Pediatric	3 (3.5)
Mixed	35 (41.2)
Unspecified	19 (22.4)
Country/Continent
Australia	9 (10.6)
Austria	5 (5.9)
China	1 (1.2)
Europe	2 (2.4)
Germany	31 (36.5)
Japan	4 (4.7)
Mexico	1 (1.2)
Norway	2 (2.4)
Singapore	1 (1.2)
Turkey	1 (1.2)
United Kingdom	2 (2.4)
United States	26 (30.6)

Most studies enrolled adult or mixed-age cohorts, with only 3.5% (n = 3) focusing exclusively on pediatric patients. Studies were conducted across 12 countries, with Germany (n = 31, 36.5%) and the United States (n = 26, 30.6%) contributing the largest shares.

Adult defined as ≥18 years old, pediatric defined as <18 years old.

Results

A total of 807 studies were queried. After 259 duplicates were removed, 548 studies were screened according to inclusion and exclusion criteria, as detailed in Figure 1 . Overall, 85 studies met inclusion criteria, each reporting at least one RTS-specific outcome following ACI or MACI of the knee. Forty-eight (56.5%) studies reported on ACI, 33 (38.8%) on MACI, and 3 (3.5%) on both ACI and MACI. A comprehensive list of included studies, along with which report on MACI and/or ACI, which report RTS (rather than general physical activity) and the types of scales they report, are detailed in Suppl. Table S1 . Studies were most commonly prospective cohort studies (n = 42, 49.4%), followed by retrospective cohort studies (n = 28, 32.9%) and randomized controlled trials (n = 15, 17.6%) (Table 1). With respect to study LOE, 31 studies were LOE IV, followed by 18 LOE III studies, 11 LOE I studies, and 7 LOE I studies ( Fig. 2 ). Eighteen studies did not specify a LOE. Twenty-eight studies (32.9%) included only adult participants, 35 (41.2%) enrolled mixed-age cohorts, and 3 (3.5%) focused exclusively on pediatric populations (Table 1). Age group was unspecified in 19 studies (22.4%). Studies were conducted across 12 countries, with Germany (n = 31, 36.5%) and the United States (n = 26, 30.6%) contributing the largest proportion. Australia, Austria, and Japan were also moderately represented (Table 1). With regard to study publication dates, there was a trimodal distribution with 11 studies (12.9%) published in 2024, 14 studies (16.5%) published in 2019, and 11 (12.9%) studies published in 2014 (Fig. 3).

Figure 2.

Level of evidence of included studies. The majority of studies were Level IV (n = 31), followed by Level III (n = 18), and Level I (n = 11). Fewer studies were classified as Level II (n = 7), and 18 studies did not specify a level of evidence.

Figure 3.

Number of included studies published per year from 2014 to 2024. Peaks in publication volume were observed in 2014 (n = 11), 2019 (n = 14), and 2024 (n = 11).

Assessment of RTS varied substantially in both modality of assessment and tools used (Figs. 4 and 5). Thirty-seven studies (43.5%) reported modality of data collection (Fig. 4). Among studies that specified data-collection modality, in-person assessments were most common (n = 19, 51.4%), followed by mixed (in-person, online, or mailed) methods (n = 11, 29.7%), online surveys (n = 6, 16.2%), and mailed (n = 1, 2.7%; Fig. 4).

Figure 4.

Modality of study-specific questionnaire administration. In-clinic assessments were the most commonly reported modality (n = 19), followed by mixed methods (n = 11) and online surveys (n = 6). Forty-eight (56.5%) studies did not clearly specify the modality of RTS data collection.

Figure 5.

Patient-reported outcome measurements (PROMs) used to assess RTS across included studies. KOOS was the most commonly used PROM (n = 61), followed by IKDC (n = 42), Lysholm (n = 34), and Tegner Activity Scale (n = 31). Only 13 studies (15.3%) reported the percentage of patients returning to sport at a specified time point. A total of 19 studies used nonvalidated or custom PROMs, while the NSARS was used infrequently. % = percent; KOOS = knee injury and osteoarthritis outcome score; IKDC = International Knee Documentation Committee; NSARS = nonsurgical anterior cruciate ligament registry score; CSAS = Cincinnati sports activity scale; PROM = patient-reported outcome measure.

The use of validated PROMs to assess RTS was inconsistent across studies (Fig. 5). The most frequently used validated PROM scales were the KOOS-S/R (n = 61, 71.8%), IKDC (n = 42, 49.4%), Lysholm Score (n = 34, 40.0%), and the Tegner Activity Scale (n = 31, 36.5%). Fewer studies utilized NSARS (n = 2, 2.4%). In addition to validated PROMs, 13 studies (15.3%) also reported RTS outcomes by explicitly stating the percentage of patients who returned to a sport (rather than just physical activity) at one or more postoperative time points.^6,19
-30 Notably, six of these studies were by Ebert et al. 19 studies (22.4%) did not use any validated PROMs, nor report postoperative RTS as a percentage. Instead, these studies relied on nonstandardized or custom measures, such as nonvalidated scales or general patient-reported satisfaction with sport participation scores.

Few studies defined the time points at which RTS was measured. Most studies reported RTS PROMs at over the 2-year time point (n = 59, 69.4%), at 2 years (n = 46, 54.1%), and at 1 year (n = 41, 48.2%) (Fig. 6). PROMs were also commonly reported at 6 months (n = 25, 29.4%) and 3 months (n = 20, 23.5%), although least frequently at 18 months (n = 6, 7.1%), 6 weeks (n = 3, 3.5%), 9 months (n = 2, 2.4%), and 2 weeks (n = 1, 1.2%).

Figure 6.

Frequency of timepoints tracked in patient-reported outcome measurements (PROMs). W = week; M = month; Y = year; PROM = patient-reported outcome measure.

Discussion

This systematic review highlights the substantial variability in how RTS is assessed following ACI and MACI. Despite the central role that RTS plays in defining surgical success and influencing patient decision-making, no consensus currently exists on how to define or measure it. This inconsistency poses significant challenges for interpreting the literature, guiding rehabilitation, and counseling patients regarding prognosis and recovery expectations. This review is unique in that it shifts focus from outcomes to measurement practices, drawing attention to the methodological gaps that complicate clinical translation. By cataloging the diversity of tools and timelines used to assess RTS, our findings lay the groundwork for standardization and future consensus-building in RTS evaluation after cartilage restoration. Furthermore, our review may serve as a reference for researchers and clinicians in guiding RTS assessment choices and common postoperative RTS timepoints (e.g., 6 months, 1 year, 2 years postoperatively) following cartilage restoration.

The most frequently used instruments to assess RTS were the KOOS-S/R and the IKDC form, appearing in 71.8% and 49.4% of studies, respectively. Their popularity may be due to their widespread validation, ease of use, and availability across multiple languages and settings.^31,32 These PROMs offer a broad overview of knee function and are sensitive to sport-specific limitations, making them appealing tools for assessing outcomes in active individuals. However, even these tools were not used consistently across studies, and many studies incorporated additional or alternative custom metrics that lacked formal validation. Moreover, although the KOOS and IKDC have demonstrated high reliability and validity for sports such as soccer, basketball, handball, and skiing, across both general and athletic populations, they may not be generalizable to all activities, particularly flexibility-based sports (e.g., dance, gymnastics, figure skating).^11,33
-40 Taken together, these findings suggest that while the KOOS and IKDC are commonly used and generally reliable, they do not fully capture the diverse criteria necessary for RTS, potentially explaining the frequent use (22.4% of studies) of multiple nonvalidated measures across studies. As such, existing PROMs may benefit from sport-specific adaptations to enhance their relevance and generalizability to diverse athletic populations.

Notably, extensive review of included studies demonstrated high variability and lack of clarity in what constitutes a successful RTS (i.e., timepoints and percentage of patients returning to any sport). This lack of standardized criteria introduces significant ambiguity into outcome reporting, making it difficult to determine whether patients returned to pre-injury levels of athletic and/or baseline activity, participated at reduced capacity, or merely resumed any form of physical activity. For example, Hurley et al.⁴¹ found that RTS rates vary widely, ranging from 33.3% to 100%, with notable variability in the time to return to on-the-field sports, particularly following ACI compared to other knee cartilage repair procedures. They also highlighted inconsistencies in rehabilitation protocols and a lack of standardized RTS guidelines in the existing literature. Without a consistent benchmark, RTS becomes a subjective and potentially misleading outcome, undermining both clinical interpretation and future research reproducibility.⁴²

In our review, we found that some studies are clear in their RTS measurements and may serve as a model for future studies on RTS in ACI or MACI. For instance, those reporting the percentage of patients who returned to a sport (e.g., general activity vs. sport-specific return) at one or more postoperative time points allow for clear delineations of when patients are actually returning to sport participation.^6,19
-30 Papers by Ebert et al. commonly reported the number or percent of patients returning to sports at given post-op timepoints and composed 6 out of 13 studies (46.2%) of studies reporting these specific metrics.^20
-24,29

Furthermore, the time points at which RTS was assessed varied dramatically, with some studies evaluating return as early as 6 months postoperatively and others extending follow-up to several years (Fig. 6). Without standardized definitions or timeframes, it becomes difficult to aggregate or compare findings across studies, replicate outcomes, or develop universal rehabilitation protocols. However, when considered collectively, these studies may be used to inform a more modern understanding of RTS as a continuum—an evolving model that emphasizes progressive recovery milestones rather than a binary return, particularly for athletes striving to regain peak performance.⁴³ Furthermore, in some contexts, differing definitions of RTS may be warranted. For instance, RTS expectations may vary depending on whether a patient is a professional athlete, recreational participant, or is not involved with sports.⁴⁴ Still, the lack of transparency or rationale for these variations across the literature undermines interpretability and clinical utility.

In addition, only three (3.5%) studies meeting inclusion criteria focused on pediatric populations, highlighting a significant gap in the literature.^20,45,46 Further research is needed to understand RTS outcomes in skeletally mature children and adolescents, who also undergo ACI or MACI procedures.^47
-49 For youth requiring knee cartilage restoration following failed conservative management, ACI and MACI are often preferred and increasingly utilized.^50,51 However, children and adolescents differ markedly from adults in terms of healing potential, physical activity demands, and rehabilitation needs.⁵² In addition, RTS expectations and timelines may need to be tailored to developmental stages, as well as academic and athletic schedules. Without sufficient pediatric data, it is challenging to establish evidence-based guidelines for this population, particularly given the increasing number of pre-professional youth athletes for whom sport plays a central role in physical development, personal identity, and mental well-being.⁵³

In light of these findings, the adoption of validated, consensus-based definitions, expansion of validated tools, and standardized timepoints for RTS reporting after ACI and MACI procedures may enhance the comparability and clinical relevance of future research. While some variability is expected due to sport-specific or patient-specific factors, establishing a core set of standardized metrics, ideally incorporating both PROMs and objective functional milestones, may support more consistent data synthesis and improve evidence-based clinical decision-making.

This review makes several novel contributions to the field. First, it is the most comprehensive synthesis to date focused explicitly on the methodological assessment of RTS-reporting practices for MACI and ACI procedures. Second, by stratifying outcomes by PROM type, timepoint, modality, and population, we offer a granular map of the inconsistencies that limit meta-analyses and real-world RTS benchmarking. Third, we identify a substantial reliance on nonvalidated, custom tools, which has not been systematically documented in the literature before. These findings underscore a need for methodologic rigor in future outcome reporting to inform patient expectations of clinical outcomes and return to their activities and sports.

Given the high variability in how RTS is defined and assessed following ACI and MACI, several key recommendations emerge from this review:

Establish Consensus-Based Definitions of RTS: A clear, standardized definition of RTS, potentially based on a continuum model (e.g., return to participation, RTS, return to performance), should be adopted across studies. These definitions should explicitly distinguish between levels of return (e.g., recreational activity vs. pre-injury performance) and account for patient-specific goals.

Utilize Validated Assessment Tools: Where possible, studies should use validated PROMS such as KOOS-S/R and IKDC, which are widely accepted and allow for comparability. The mode of data collection (e.g., in-person, online, phone) should also be reported clearly and standardized where possible. Consistency in modality can improve data reliability and reduce variability related to response bias. Validated assessment tools may also be expanded or modified for more generalizability across athletic activities and patient populations.

Standardize Timepoints for RTS Evaluation: Future research should assess RTS at consistent and clinically meaningful timepoints, such as 6, 12, and 24 months postoperatively, to improve interpretability, facilitate longitudinal analysis, and guide rehabilitation protocols.

Tailor RTS Metrics to Specific Populations and Sports: RTS assessments should account for variations in athletic level (e.g., professional vs. recreational), sport-specific demands, and patient demographics, including age and developmental stage. However, such tailoring must be accompanied by transparent rationale and consistent reporting standards.

Expand Research in Pediatric Populations: There is a critical need for prospective studies investigating RTS outcomes in pediatric and adolescent patients undergoing ACI or MACI. These populations have unique rehabilitation needs and activity profiles that warrant separate consideration in both clinical care and research.

In summary, this review offers an important call for future randomized controlled trials on cartilage-restoration procedures to develop and utilize standardized, easily interpretable RTS measures and sports-specific scales. Similar work has highlighted inconsistent RTS reporting for other orthopedic surgeries, such as for ACL reconstruction,¹⁷ although this has not been evaluated for MACI/ACI. The evaluation of RTS in the current study is also timely in the context of the rising prevalence of cartilage-restoration surgeries, including in athletic patient populations who may be seeking guidance from clinicians and the literature on postoperative RTS protocol and expectations.

Limitations

This study has several limitations. First, due to the descriptive nature of the synthesis and the inherent heterogeneity of the included studies, we were unable to conduct a quantitative meta-analysis. Second, we relied on the reporting quality of individual studies; many lacked detailed definitions of RTS or did not specify PROM subscale scores. Next, this analysis includes publications from 2014 through December 2024. Although newer studies on two-stage cell expansion cartilage procedures continue to emerge, the most recent publications from 2025 are not captured in this review. Nonetheless, the findings provide a timely and comprehensive synthesis of, and reflection on, the existing literature on cartilage restoration. In addition, while we combined studies involving ACI and MACI in our analysis, we recognize that outcome profiles may differ between the two procedures. However, given their shared biological mechanism and the evolution of MACI from ACI, we considered them appropriate to group for the purpose of assessing RTS-reporting methodology, rather than clinical efficacy. Furthermore, the methodology used to report RTS in ACI studies remains relevant and informative for MACI, given their procedural continuity. Finally, despite extensive database searching, it is possible that some relevant studies were missed due to inconsistent use of RTS-related terminology in titles or abstracts.

Conclusions

RTS remains a critical yet inconsistently defined outcome following ACI and MACI. This systematic review demonstrates substantial variability in how RTS is assessed, including inconsistent use of validated PROMs, variable reporting timepoints, widespread use of custom or nonvalidated tools, and lack of sports- or activity-specific measures. Future research should prioritize broader use and refinement of validated PROMs. Standardized RTS metrics could aid clinicians in providing more accurate timelines and expectations to patients undergoing knee cartilage-restoration procedures. In summary, improving the consistency and transparency of RTS reporting is essential for enhancing clinical decision-making, informing rehabilitation protocols, and aligning outcome expectations with patient goals.

Supplemental Material

sj-docx-1-car-10.1177_19476035251379214 – Supplemental material for High Variability in Return-to-Sport Assessment After Autologous Chondrocyte Implantation of the Knee: A Systematic Review

Supplemental material, sj-docx-1-car-10.1177_19476035251379214 for High Variability in Return-to-Sport Assessment After Autologous Chondrocyte Implantation of the Knee: A Systematic Review by Camila Vicioso, Mark Kurapatti, Luca M. Valdivia, Ryan Smolarsky, Sophie deBettencourt, Avanish Yendluri, Prabhjot Singh, Nikan K. Namiri, Hulaimatu Jalloh and Robert L. Parisien in CARTILAGE

Footnotes

Authors’ Note

Investigation performed by the Scientific Collaborative for Orthopedic Research and Education (SCORE) Group.

ORCID iDs

Camila Vicioso

Mark Kurapatti

Ryan Smolarsky

Avanish Yendluri

Robert L. Parisien

Ethical Approval

Ethical approval was not required for this study, as it is a systematic review of previously published literature and did not involve human participants, identifiable human data, or human tissue.

Consent to Participate

Not applicable.

Consent for Publication

Not applicable.

Funding

The authors received no financial support for the research, authorship, and/or publication of this article.

Declaration of Conflicting Interests

The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Data Availability Statement

All data supporting the findings of this study are publicly available in the original published literature. A full list of included articles can be provided upon request.

Supplemental Material

Supplementary material for this article is available on the Cartilage website at .

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