Abstract
Background:
Meniscal replacement aims to restore function and delay joint degeneration in patients with symptomatic meniscus deficiency; nonetheless, comparative evidence among different implant options—meniscal allograft transplantation (MAT), collagen meniscus implant (CMI), and polyurethane scaffolds—remains limited.
Purpose:
To systematically review and compare the clinical outcomes of MAT, CMI, and Actifit (polyurethane scaffold).
Study Design:
Systematic review; Level of evidence, 4.
Methods:
Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a standardized search and review strategy was employed to identify clinical evidence of any designation examining clinical outcomes and implant-associated adverse events after meniscal replacement with specified implants. Effect sizes were calculated via standardized mean deviations and illustrated through forest plots to compare against the minimal clinically important difference (MCID) for relevant patient-reported outcome measures. The primary outcomes were clinically significant improvements in functional status and pain relief. Secondary outcomes included failure rates, reoperations, and other reported adverse events, as well as indirect evidence of chondroprotection.
Results:
A total of 50 studies were included. All 3 implant types yielded statistically significant functional improvements (all reported P < .05), with scores such as the International Knee Documentation Committee and the Lysholm often exceeding the MCID. However, pain relief was inconsistent and frequently failed to achieve the MCID. Failure rates differed markedly among implants, with the mean failure rate being lowest for CMI (5.2%), highest for Actifit (15.9%), and intermediate for MAT (11.4%). Radiological evidence indicated a potential chondroprotective effect; nevertheless, it was not conclusive.
Conclusion:
Meniscal replacement effectively improves patient function, but pain relief is unreliable, and failure risks vary by implant type. The current evidence is insufficient to definitively recommend one implant over another. Clinical decisions must be individualized, considering patient-specific factors, concomitant pathologies, and the unique risk profile of each implant. High-quality, head-to-head randomized controlled trials are urgently needed.
The meniscus is crucial for knee joint biomechanics, playing essential roles in load-bearing, shock absorption, and cartilage health. Loss of meniscal tissue increases contact stress, accelerating articular cartilage damage and the onset of osteoarthritis. 3
Meniscal allograft transplantation (MAT) is recognized as an effective treatment for young, active patients to restore load-bearing capacity and provide chondroprotective effects.62,66,67 Long-term studies have shown promising outcomes, with a notable percentage of allografts maintaining functionality even after 10 to 15 years. 43 Still, problems with immunological rejection, disease transmission, inadequate long-term chondroprotection, and limited graft availability persist. 51 In response, tissue-engineered meniscus has emerged as a promising implant for meniscal repair, utilizing innovative techniques to regenerate damaged tissues.15,28,33 Despite extensive in vitro and in vivo studies in this field, its clinical application in humans remains limited. 65 Currently, 2 commercial scaffolds are available for reconstructing meniscal defects: collagen meniscus implant (CMI) (Ivy Sports Medicine) and polyurethane scaffolds (Actifit) (Orteq Ltd).12,69 CMI is a biodegradable type 1 collagen scaffold with supplemented glycosaminoglycans derived from bovine Achilles tendons. Actifit is a porous scaffold composed of polycaprolactone (80%) and polyurethane (20%). Although MAT and tissue-engineered scaffolds (eg, CMI and Actifit) are indicated for distinct clinical scenarios—total/subtotal versus partial meniscal deficiency, respectively—a grey zone of clinical uncertainty persists in treatment selection. Furthermore, the literature lacks a comprehensive review that systematically presents the clinical outcomes, failure modes, and risk profiles of these mainstream replacement strategies within their respective indications. Therefore, this systematic review aims to comprehensively analyze the current clinical evidence for MAT, CMI, and Actifit. Our goal is to provide a clearer, evidence-based framework for clinical decision-making across various scenarios, rather than directly determining the superiority of one implant over another.
Methods
Data Sources and Search Strategy
We conducted this systematic review in accordance with the PRISMA-2020 (The Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines, 44 and the protocol for this systematic review was registered on PROSPERO (International Prospective Register of Systematic Reviews). PubMed, Embase, and Cochrane Library were reviewed for all English-language studies published before September 8, 2024. The search strategy was constructed to maximize sensitivity, combining medical subject headings (MeSH) with free-text words. The core search concepts were “meniscus” and “meniscal replacement.” For example, the full search string for the PubMed/MEDLINE database was as follows: ((("meniscus"[MeSH Terms]) OR ("meniscal"[All Fields])) AND (("transplantation"[MeSH Terms]) OR ("scaffold"[All Fields]) OR ("implant"[All Fields]) OR ("replacement"[All Fields]))). Additionally, the reference lists of all relevant articles were manually reviewed to identify further relevant publications. Two researchers (X.Y. and Y.M.) independently completed the literature search, with discrepancies resolved by a senior author (W.F.).
Inclusion and Exclusion Criteria
To be included, studies had to report on patient-reported outcome measures (PROMs) and implant-related adverse events, have any level of evidence (according to the 5-level system 71 ), be written in English, include a minimum of 2-year follow-up (FU), and assess meniscal replacement used to treat knees affected by meniscal loss. This review focused specifically on studies evaluating MAT, CMI, and Actifit. We excluded biomechanical reports, case reports, preclinical studies, reviews, articles not written in English, commentaries, and topics not centered on the meniscus.
Data Extraction
Raw data from included studies were extracted independently by the same 2 independent authors based on the predefined eligibility criteria: (1) trial details, including the type of the study, author's initials, publication year, level of evidence, length of FU; (2) participant information, including the number of patients, age, sex, index knee, location of implant; (3) surgical description, including the type of intervention, lesion and implant characteristics, method of allograft preservation, classification of chondropathy, and concomitant procedures; and (4) clinical parameters rated using PROMs. All reported clinical baseline and final follow-up outcome scores were collected and reviewed. Moreover, adverse events, radiological, and histological characteristics were also extracted. The primary purpose of this data extraction phase was to systematically collect all relevant information concerning the predefined primary and secondary outcomes, including specific PROMs, failure definitions and rates, radiological parameters, and second-look arthroscopic findings for each included meniscal replacement type.
Methodology Quality Assessment
The methodological quality of the collected data was assessed using a modified version of the Coleman methodology score (CMS) (Appendix Table 1). 37 The risk of bias was appraised according to the type of study identified. The Revised Tool for Risk of Bias in Randomized Trials (RoB 2.0) was used for randomized controlled trials, and the Methodological Index for Non-Randomized Studies (MINORS) was used for nonrandomized studies.55,59 Two separate reviewers assessed study quality independently, with disagreements resolved by consensus with a third author (W.F.).
Statistical Analysis
Data from all studies were represented with descriptive summary tables. Ranges with medians were provided for all numerical demographics. Forest plots were generated using the RStudio meta package for the most commonly used PROMs—including the Lysholm score, Tegner activity score, visual analog scale for pain (VAS–Pain), and International Knee Documentation Committee (IKDC) subjective form—as they were the most commonly utilized PROMs among included studies. 60 For each outcome score, postoperative improvement was calculated as the standardized mean difference between baseline (preoperative) and follow-up (postoperative) scores and compared with established minimal clinically important difference (MCID) thresholds for outcomes after knee injuries (IKDC = 9.9; Lysholm = 10.1; Tegner = 1; and VAS–Pain = 2.7), as reported by the American Orthopaedic Society for Sports Medicine (AOSSM) Outcomes Task Force. 29
Results
Search Results and Basic Characteristics
The initial search yielded 3346 total results, and after screening the abstracts, 167 full-text articles were assessed for eligibility. Of these, 50 articles met the inclusion criteria (Figure 1). Studies reviewed were published between 1999 and 2023. The age of patients ranged from 19.3 to51 years (median, 36.2 years), with 70.7% being men. Table 1 summarizes the basic characteristics of the included studies, which comprise 1 randomized controlled trial, 6 prospective cohort studies, 1 retrospective cohort study, 3 case-control studies, and 39 case series (all involving >5 patients). Also, 17 of the total 50 studies reported results on MAT, 22 studies on Actifit, 13 studies assessed patients treated with CMI, and 2 studies compared the effects of CMI and Actifit scaffolds.7,48 Detailed data are presented in Appendix Table 1.
PRISMA flowchart of study selection. PRISMA, Preferred Reporting Items for Systematic Reviews and Meta-Analyses.
Basic Characteristics of Included Studies α
Data are presented as n, mean. CMI, collagen meniscal implant; LOE, level of evidence; MAT, meniscal allograft transplantation; NR, not reported; RCT, randomized controlled trial.
16 in the medial, 2 in the lateral, and 1 bilateral.
Methodology Quality Assessment
The modified CMS scores of the included studies ranged from 41 to 77 (median, 64), suggesting a moderate overall methodological quality, although a considerable range in quality was observed (Appendix Table 1). As evaluated with RoB 2.0, the only randomized controlled trial was graded as having some concerns. The MINORS score ranged from 10 to 22 (median, 14) (Appendix Table 2).
PROMS and MCID
Of the 50 studies meeting the inclusion criteria, 17 different scoring systems were presented in the literature: the most frequently collected PROMs were the Lysholm score (n = 36), followed by the VAS–Pain (n = 34), the Tegner activity score (n = 32), and the IKDC subjective form (n = 27). Statistically significant improvements were observed in all groups for all PROMs from preoperative values to final follow-up (P < .05) (Table 2). In the included studies, the mean recorded improvements in the Lysholm score were higher than the MCID values for all groups (Figure 2). Similarly, IKDC scores generally exceeded the MCID for the MAT and Actifit groups (Figure 3). In 10 out of 14 investigations, the Tegner score exceeded the MCID (6 of 7 for MAT; 2 of 4 for Actifit; and 2 of 3 for CMI) (Figure 4). In stark contrast to these encouraging functional gains, however, pain relief was far less consistent. Of the 23 studies reporting VAS scores, only 9 demonstrated improvements exceeding the MCID, with none in the CMI group reaching the MCID threshold (Figure 5).
Preoperative and Final Follow-up PROMs α
Data are presented as n (%). Statistical significance was set at P < .05 for all groups. Actifit, polyurethane scaffold; CMI, collagen meniscal implant; IKDC, International Knee Documentation Committee; MAT, meniscal allograft transplantation; Postop, postoperative; Preop, preoperative; PROM, patient-reported outcome measure; VAS–Pain, visual analog scale for pain.
Forest plot with the MCID line for the Lysholm score. Actifit, polyurethane scaffold; CMI, collagen meniscus implant; CMS, Coleman methodology score; FU, follow-up; MCID, minimal clinically important difference; MAT, meniscal allograft transplantation; MD, mean difference; MINORS, Methodological Index for Nonrandomized Studies; SMD, standardized mean difference.
Forest plot with the MCID line for the IKDC score. Actifit, polyurethane scaffold; CMI, collagen meniscus implant; CMS, Coleman methodology score; FU, follow-up; MCID, minimal clinically important difference; MAT, meniscal allograft transplantation; MD, mean difference; MINORS, Methodological Index for Nonrandomized Studies; SMD, standardized mean difference.
Forest plot with the MCID line for the Tegner score. Actifit, polyurethane scaffold; CMI, collagen meniscus implant; CMS, Coleman methodology score; FU, follow-up; MCID, minimal clinically important difference; MAT, meniscal allograft transplantation; MD, mean difference; MINORS, Methodological Index for Nonrandomized Studies; SMD, standardized mean difference.
Forest plot with the MCID line for the VAS–Pain score. Actifit, polyurethane scaffold; CMI, collagen meniscus implant; CMS, Coleman methodology score; FU, follow-up; MCID, minimal clinically important difference; MAT, meniscal allograft transplantation; MD, mean difference; MINORS, Methodological Index for Nonrandomized Studies; SMD, standardized mean difference. VAS–Pain, visual analog scale for pain.
Surgical Findings
The mean length of the Actifit implant ranged from 35.6 to 46.1 mm (median, 42.9 mm), whereas in the CMI group, it ranged from 34 to 48.2 mm (median, 45 mm) (Appendix Table 3). The most adopted preservation method of allograft used was fresh-frozen, exclusively in 10 studies,10,23-25,39,53,57,62,72,74,75 cryopreserved allografts in 3 studies,66-68 and deep-frozen allografts in 2 studies.46,79 Seventeen studies reported distinct operative techniques for the fixation of graft; in summary, most studies employed the bone bridge technique (bridge in-slot,10,38,53,72 keyhole25,38,57,72) for lateral MAT, and the bone plug technique for medial MAT.10,25,38,53,62,72,79 A soft tissue fixation technique was used in 5 studies.23,24,39,74,75 The Actifit and CMI scaffolds were solely sutured to the residual meniscal tissue for fixation. Only 1 study reported on isolated MAT, 79 whereas concomitant procedures were performed in the remaining studies. The concomitant surgeries of the studies could be classified as ligament reconstructions, osteotomies, and cartilage treatments. The most frequent associated procedures were anterior cruciate ligament reconstruction (ACLR), high tibial osteotomy (HTO), and microfracture.
Radiological and Second-Look Arthroscopic Findings
One of the most commonly evaluated parameters by the authors was meniscal extrusion (ME). The extruded meniscus was more usual in the MAT (7 of 17 studies) and Actifit (12 of 22 studies) groups, but not for the CMI scaffolds. As for the extrusion rates, Marcacci etal 39 found 69% of the allografts extruded, Torres-Claramunt etal 62 reported ME increased from 29.7% obtained at the 5-year FU to 72.5% observed at the last FU. The absolute ME of the Actifit scaffolds can be achieved by 3.5 mm in 4 studies.1,18,22,26 Of note, 6 studies revealed that the extrusion findings in magnetic resonance imaging (MRI) did not correlate with clinical outcomes.1,13,16,18,25,46,54 Although considerable ME was observed, 5 studies showed that the maximal extrusion was stabilized at mid-term follow-up and remained unchanged at the final follow-up.1,25,26,34,46 Regarding the side of extrusion, 2 studies identified that it was not statistically different between the medial and lateral grafts.17,72
Regarding the chondroprotective effect of the implants, there is some evidence from radiographs and MRI studies included in the analysis. A stable cartilage status of the index compartment in the Actifit group was demonstrated in 6 studies compared with the baseline.4,8,14,16,34,61,64 Radiographs showed that the joint space width remained almost unchanged from the initial evaluation up to the final FU measurement for the MAT (4 studies23,53,62,79) and CMI (3 studies41,50,78) groups.
Second-look arthroscopy was described in 15 studies (5 on MAT23,46,52,72,79; 4 on Actifit5,8,26,65; and 6 on CMI9,49,50,58,73,76). Two studies demonstrated that the allografts were completely intact and had excellent peripheral vascularization.23,79 In the Actifit and CMI scaffolds, 8 studies showed that scaffolds were well integrated with the surrounding neotissue but reduced in size compared with the original implant.5,7-9,26,49,50,73 For the cartilage status during relook arthroscopies, Paša etal 46 reported that 19 of 23 patients who underwent second-look arthroscopy demonstrated improved cartilage condition compared with the condition before meniscal allograft transplantation. Bulgheroni etal 7 found that the articular cartilage appeared intact in most patients in both the Actifit and CMI groups, without signs of progression of any existing articular injury. These findings may suggest the chondroprotective effect of these implants.
Adverse Events
The most commonly reported adverse events were implant failures (Appendix Table 4). A treatment failure was deemed to have occurred if an additional surgical intervention was required for the index defect, and the surgeon determined that the necessity for this supplementary procedure was attributable to an uncertain, potential, likely, or definitive link to the scaffold and/or the initial procedure. In the included studies, total knee arthroplasty, unicompartmental knee arthroplasty, allograft removal or revision, and re-transplantation were considered surgical failures for the initial MAT.24,38,53,62,66-68,75 Failure rates for the MAT group ranged from 75 4.8% to 62 42.1%, with a mean of 11.4% (89 failures in 779 allografts); in the Actifit group, failure rates varied from 11 6% to 14 31.8%, with a mean of 15.9% (62 failures in 391 scaffolds); only 2 studies in the CMI group reported that the failure rates were 4.5% and 8%, with a mean of 5.2% (6 failures in 116 scaffolds).27,41
Discussion
The principal finding of this systematic review is not to declare a superior meniscal replacement strategy, but to systematically identify a prevalent function-pain discrepancy and to quantify the distinct failure rates of major implant types within their respective clinical contexts. Our analysis confirms that while all implant types significantly improve functional scores, this success contrasts starkly with the outcomes for pain, where improvements frequently failed to reach the MCID. The most probable explanation for this persistent pain lies in the patient's preoperative articular cartilage status. Meniscectomy initiates a degenerative cascade by creating abnormal jointcontact stresses that accelerate chondral wear. 2 Consequently, many candidates for meniscal replacement already have significant, often painful, chondral lesions. In this context, a crucial study by Parkinson etal 45 identified severe preexisting cartilage damage (Outerbridge grade 3-4) as the single most powerful independent predictor of MAT failure and inferior clinical outcomes. This suggests that while a meniscal implant may address the meniscus problem, it cannot reverse the established arthritis problem. Therefore, a critical clinical implication is the need for rigorous preoperative patient selection and counseling.
Although a key rationale for meniscal replacement is the potential to protect articular cartilage from further degradation, our review finds that the evidence supporting this effect remains suggestive rather than conclusive. Observations of stable joint space width on radiographs and preserved cartilage on MRI are encouraging but must be interpreted with significant caution. These are indirect, surrogate endpoints whose correlation with the true histological health of the cartilage is unproven. A pivotal systematic review by Smith etal 56 concluded that while some evidence for chondroprotection after MAT exists, it is derived from studies of generally low quality with a high risk of bias. The long-term follow-up by Torres-Claramunt etal 62 provides a sobering perspective, showing that despite good clinical outcomes at 15 years, ME and joint space narrowing progressed over time, with a graft failure rate of 42.1%. A deeper issue lies in the inherent limitations of diagnostic imaging. For instance, a study by Kim etal 31 comparing postoperative MRI with second-look arthroscopy after MAT found that MRI had low specificity and accuracy for assessing the anterior portion of the graft, often overestimating the degree of pathology. This demonstrates a clear disconnect between imaging findings and the graft's true biological state. Furthermore, the lack of studies comparing radiological outcomes to a contralateral healthy knee or a nonoperative control group significantly limits the persuasiveness of the current evidence. Thus, while meniscal replacement may offer a chondroprotective potential, it should not be presented to patients as a guaranteed method to halt arthritis. Honesty about the limited evidence is essential for ethical clinical practice.
The failure rates reported in this review—averaging 11.4% for MAT, 15.9% for Actifit, and 5.2% for CMI—represent not just a statistic, but a significant event with profound long-term consequences for the patient, often leading to revision surgery or arthroplasty. The underlying reasons for failure differ substantially between allografts and synthetic scaffolds, reflecting their distinct biological and mechanical risk profiles. MAT carries risks inherent to transplantation, including the potential for an immune response, particularly when fixed with bone plugs, and the albeit minimal risk of disease transmission. 51 Conversely, synthetic scaffolds, such as CMI and Actifit, face challenges related to materials science. Histological studies of explanted scaffolds reveal that CMI, a collagen-based implant, tends to remodel into vascularized fibrocartilage, whereas Actifit, a polyurethane scaffold, is more often replaced by avascular, cartilage-like tissue. 7 This biological difference may influence long-term durability, as vascularized tissue could possess superior integration and repair capacity, potentially explaining the lower failure rate of CMI observed in our review. The failure of scaffolds can also result from incomplete tissue ingrowth, material degradation, or a chronic foreign body reaction, leading to mechanical incompetence. Clinicians must weigh these distinct risk profiles—immunology and supply for MAT versus biomaterial performance for scaffolds—and select the most appropriate implant based on the patient's specific anatomy, pathology, and activity demands.
This systematic review, like most published studies in the field, was unable to perform a subgroup analysis comparing the clinical outcomes of medial versus lateral meniscal replacements. The fundamental reason is that the primary studies overwhelmingly report these outcomes as a consolidated group.This practice masks crucial anatomical, biomechanical, and prognostic differences between the 2 compartments, severely limiting our precise understanding of treatment efficacy. Multiple studies have confirmed that joint degeneration is more rapid and clinical symptoms are more severe after lateral meniscectomy.30,40 Correspondingly, after meniscal replacement, lateral MAT yields superior clinical outcomes (eg, IKDC and Knee injury and Osteoarthritis Outcome Scores) compared with medial MAT. 70 Conversely, medial MATs exhibit greater graft extrusion, and medial implantation has been identified as an independent predictor of surgical failure. 45 This is likely because the biomechanical environment of the medial compartment places higher demands on graft fixation and integration. Therefore, it is imperative that all future clinical studies on meniscal replacement report and analyze medial and lateral outcomes separately. The practice of lumping them together is no longer scientifically tenable and must be considered a major methodological flaw.
The vast majority of cases included in this review involved concomitant procedures, most commonly ACLR and HTO. This represents a major confounding variable that makes it nearly impossible to attribute the observed clinical improvements solely to the meniscal implant. ACLR is itself a highly successful procedure for restoring knee stability and is known to improve PROMs significantly. 19 When ACLR is performed concurrently with MAT, the improvements in function and satisfaction may largely be driven by the restoration of stability from the ligament reconstruction, not the meniscal graft. 63 Similarly, HTO is a powerful intervention designed to unload the affected compartment by altering limb alignment, thereby alleviating pain and improving function. 36 An authoritative editorial has explicitly questioned the added value of combining MAT with HTO, highlighting that this combined approach significantly increases reoperation rates without proven benefit in delaying total knee arthroplasty. 47 This phenomenon reveals a core issue: in many combined procedures, the meniscal implant may be the passenger, while the ACLR or HTO is the driver of the clinical outcome. Due to limitations in the primary data, this systematic review could not quantify the specific contributions of these concomitant procedures through subgroup or regression analysis. This severely weakens our ability to determine the independent therapeutic effect of meniscal replacement. We therefore strongly advocate for more targeted future research designs. Only through such rigorous investigation can we parse out the true, independent therapeutic value of meniscal replacement in the complex environment of multi-pathology knees.
Given the complex considerations of implant choice, prognostic factors, and confounding variables, a structured framework is essential to guide clinical practice. To this end, we developed a stratified clinical decision-making flowchart based on the findings of this review (Figure 6). This algorithm offers a clear, evidence-based roadmap that addresses the grey zone in treatment selection by first triaging patients based on defect type. It then guides clinicians in integrating critical modifying factors, such as chondral status and limb alignment, thereby improving shared decision-making. By systematically identifying the function-pain discrepancy and quantifying implant-specific risks, our framework equips clinicians to better manage patient expectations regarding pain relief and long-term outcomes, potentially enhancing patient satisfaction and reducing unnecessary revisions. This systematic approach underscores the importance of a holistic surgical plan and aims to support individualized, evidence-based patient care.
Clinical decision-making flowchart for meniscal replacement. Actifit, polyurethane scaffold; ACL, anterior cruciate ligament; ACLR, anterior cruciate ligament reconstruction; Actifit, polyurethane scaffolds; CMI, collagen meniscus implant; DFO, distal femoral osteotomy; HTO, high tibial osteotomy; MAT, meniscal allograft transplantation; MRI, magnetic resonance imaging; TKA, total knee arthroplasty; UKA, unicompartmental knee arthroplasty.
Limitations
The most significant limitation of this review is the inclusion of treatment strategies with distinct indications (MAT vs scaffolds) within a single analysis. We must emphasize that our intent was not a direct head-to-head comparison, as these technologies are not clinically interchangeable. Instead, by systematically presenting their evidence side by side, we aimed to provide a comprehensive view of the current meniscal replacement landscape. Beyond this overarching conceptual limitation, our findings are also constrained by several weaknesses inherent to the available literature. Primarily, the majority of studies were Level 4 evidence, which directly limits the applicability of our conclusions across all clinical scenarios. Additionally, significant heterogeneity existed among the primary studies in both methodology (eg, inclusion criteria, definitions of failure) and patient populations (eg, age, activity level, body mass index). Combined with the small sample sizes and short follow-up periods common in many studies, these factors collectively reduce the certainty of the current evidence. These deficiencies in the primary data, in turn, imposed several analytical constraints on our review. A key limitation was our inability to perform a subgroup analysis comparing medial and lateral meniscal replacements, as most primary studies did not report these outcomes separately, potentially obscuring important prognostic differences. Similarly, inconsistent reporting of material-specific complications (eg, scaffold dissolution, secondary synovitis) precluded a systematic quantitative analysis. The frequent use of concurrent procedures (eg, ACLR, HTO) also acted as a major confounding variable, and their specific contributions to the outcomes could not be isolated in this review. Finally, it must be acknowledged that the narrow indications for meniscal grafting inherently limit the feasibility of conducting large-scale, high-level studies. Despite these challenges, systematic reviews such as this one are crucial for synthesizing the current landscape of evidence and identifying subtle signals in the data that can inform future research directions. These limitations, alongside the inherent difficulties in this field of research, may collectively explain why the clinical application of meniscal implants remains limited.
Conclusion
This systematic review confirms that while meniscal replacement (MAT, CMI, Actifit) effectively improves patient function, its efficacy for pain relief is unreliable, and failure risks differ among implants. The quality and quantity of the current evidence are insufficient to support any single implant as a universally superior option. Therefore, clinical decision-making must be highly individualized, based on a meticulous assessment of patient age, chondral status, concomitant pathologies, and the specific risk profile of each implant. Future research must adopt more rigorous designs, specifically head-to-head randomized controlled trials with stratified analyses for compartmental location and concurrent procedures, to truly advance evidence-based practice in this field.
Supplemental Material
sj-docx-1-ojs-10.1177_23259671251394376 – Supplemental material for Clinical Outcomes of Meniscal Replacement for Meniscus Deficiency: A Systematic Review of Current Evidence
Supplemental material, sj-docx-1-ojs-10.1177_23259671251394376 for Clinical Outcomes of Meniscal Replacement for Meniscus Deficiency: A Systematic Review of Current Evidence by Xiaolong Yang, Yunhe Mao, Yi Zhou, Tianhao Xu and Weili Fu in Orthopaedic Journal of Sports Medicine
Footnotes
Acknowledgements
The authors did not utilize any writing assistance for this manuscript. In accordance with the TITAN Guideline Checklist 2025, the authors declare that no artificial intelligence (AI) or AI-assisted tools were used in the research or preparation of this manuscript.
Final revision submitted July 23, 2025; accepted October 17, 2025.
The authors have declared that there are no conflicts of interest in the authorship and publication of this contribution. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
References
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
