Meniscal Repair of Degenerative Horizontal Cleavage Tears Using Fibrin Clots: Clinical and Arthroscopic Outcomes in 10 Cases

Enhancing meniscal repair with tough adhesive puncture sealing (TAPS) suture: A proof-of-concept study on bovine cadaveric knees

Purpose

The objective was to use cyclic tensile loading to compare the gap formation at suture site of three different suture materials to repair bovine radial meniscal tears: (1) polyglactin sutures, (2) tough adhesive puncture sealing (TAPS) sutures and (3) ultra-high molecular weight polyethylene (UHMWPE) sutures.

Methods

Twelve ex vivo bovine knees were dissected to retrieve the menisci. Complete radial tears were performed on 24 menisci, which were then separated into three groups and repaired using either pristine 2-0 polyglactin sutures, TAPS sutures (2-0 polyglactin sutures coated with adhesive chitosan/alginate hydrogels) or 2-0 UHMWPE sutures with a single stitch. The repaired menisci were clamped onto an Instron machine and underwent cyclic loading between 5 and 25 N at a frequency of 0.16 Hz. Gap formation between the edges of the tear was measured after 500 cycles using an electronic caliper, when the meniscus was still on the Instron without any load applied.

Results

Mean gap formation was 5.22 mm (±1.70) for the 2-0 polyglactin sutures, 2.48 mm (±0.25) for the TAPS sutures, and 4.85 mm (±1.55) for the 2-0 UHMWPE sutures. The gap was significantly smaller in the TAPS sutures group compared to the two others because of better force dispersion, decreasing tissue damage by suture indentation and potentially leading to better meniscal healing.

Conclusions

From a biomechanical standpoint, coated sutures held the edges of radial meniscal tears closer together compared to conventional sutures. This technology has the potential to reduce tissue damage and improve the success rate of meniscal repairs.

Level of Evidence

controlled laboratory study.

All-Inside Arthroscopic Tie-Grip Suture Repair for Radial Tear in the Midbody of Lateral Meniscus Using an All-Inside Device and Slotted Cannula

Inside-out repair of meniscal tears is the gold standard surgical approach; however, its use is limited by the need for a posterior incision and neurovascular risk. In this Technical Report, we present details of the all-inside arthroscopic tie-grip approach for repairing a radial tear of the midbody of the lateral meniscus using an all-inside device (TRUESPAN) and a slotted cannula. In contrast to the inside-out approach, this technique helps reduce surgical invasiveness and provides stable fixation as the vertical mattress sutures bundle the circumferential fibers and act as rip stops for the horizontal sutures. However, the operating surgeon must understand proper insertion techniques to successfully use the devices required for this procedure.

Application of adhesives in the treatment of cartilage repair

From degeneration causing intervertebral disc issues to trauma‐induced meniscus tears, diverse factors can injure the different types of cartilage. This review highlights adhesives as a promising and rapidly implemented repair strategy. Compared to traditional techniques such as sutures and wires, adhesives offer several advantages. Importantly, they seamlessly connect with the injured tissue, deliver bioactive substances directly to the repair site, and potentially alleviate secondary problems like inflammation or degeneration. This review delves into the cutting‐edge advancements in adhesive technology, specifically focusing on their effectiveness in cartilage injury treatment and their underlying mechanisms. We begin by exploring the material characteristics of adhesives used in cartilage tissue, focusing on essential aspects like adhesion, biocompatibility, and degradability. Subsequently, we investigate the various types of adhesives currently employed in this context. Our discussion then moves to the unique role adhesives play in addressing different cartilage injuries. Finally, we acknowledge the challenges currently faced by this promising technology.

How to Improve Meniscal Repair through Biological Augmentation: A Narrative Review

Since the role of the menisci in knee stability, proprioception, and homeostasis has been well established, significant efforts have been made to repair meniscal tears, resulting in excellent clinical outcomes and a reduction in the progression of knee osteoarthritis (OA). However, varying failure rates have been reported, raising questions regarding the healing potential in cases of complex injuries, poorly vascularized and degenerated areas, and generally in the presence of unfavorable biological characteristics. Therefore, over the last few decades, different strategies have been described to increase the chances of meniscal healing. Biological augmentation of meniscal repair through various techniques represents a safe and effective strategy with proven clinical benefits. This approach could reduce the failure rate and expand the indications for meniscal repair. In the present study, we thoroughly reviewed the available evidence on meniscal repair surgery and summarized the main techniques that can be employed to enhance the biological healing potential of a meniscal lesion. Our aim was to provide an overview of the state of the art on meniscal repair and suggest the best techniques to reduce their failure rate.

Biologic Augmentation of Isolated Meniscal Repair

PURPOSE OF REVIEW

The limited blood supply and intrinsic healing capacity of the meniscus contributes to suboptimal tissue regeneration following injury and surgical repair. Biologic augmentation techniques have been utilized in combination with isolated meniscal repair to improve tissue regeneration. Several innovative strategies such as Platelet-Rich Plasma (PRP), fibrin clots, mesenchymal stem cells (MSCs), bone marrow stimulation, meniscal scaffolds, and meniscal wrapping, are being explored to enhance repair outcomes. This article provides a comprehensive review of recent findings and conclusions regarding biologic augmentation techniques.

RECENT FINDINGS

Studies on PRP reveal mixed outcomes, with some suggesting benefits in reducing failure rates of isolated meniscal repair, while others question its efficacy. Fibrin clots and PRF (Platelet-rich fibrin), although promising, show inconsistent results and lack sufficient evidence for definitive conclusions. MSCs demonstrate potential in preclinical studies, but clinical trials have been limited and inconclusive. Bone marrow stimulation appears effective in certain contexts, but its broader applicability remains uncertain. Meniscal scaffolds, including CMI (Collagen Meniscal Implants) and Actifit (polyurethane scaffolds), show encouraging short- and mid-term outcomes but have not consistently surpassed traditional methods in the long term. Meniscal wrapping is infrequently studied but demonstrates positive short-term results with certain applications. The review reveals a diverse range of outcomes for biologic augmentation in meniscal repair. While certain techniques show promise, particularly in specific scenarios, the overall efficacy of these methods has yet to reach a consensus. The review underscores the necessity for standardized, high-quality research to establish the definitive effectiveness of these biologic augmentation methods.

Non-absorbable Suture-Loaded Anchors for Finger Pulley Reconstruction

A 59-year-old woman, who previously underwent surgery on her left long finger A1 pulley and left small finger distal interphalangeal joint for triggering and mallet deformity at another medical facility in March 2021, sought evaluation at an Orthopedics Hand clinic. She presented with limited finger movement, a flexion contracture, and difficulty extending her left long finger. Examination revealed an A2 pulley injury with extensive scar tissue. Subsequently, she underwent surgery to remove the scar tissue and reconstruct the A2 pulley using suture tape anchors. This case highlights the negative outcome following A1 pulley release due to an unintended A2 injury, resulting in significant scarring and an intrinsic plus digit posture. Additionally, it underscores the potential effectiveness of using non-absorbable synthetic sutures to minimize scarring and promote an early range of motion in cases where healing leads to excessive scarring around the flexor tendon sheath.

Greater rate of return to play and re-injury following all-inside meniscal repair compared to the inside-out technique: a systematic review

INTRODUCTION

Inside-out and all-inside arthroscopic meniscal repairs are widely performed. However, it remains unclear which method promotes greater clinical outcomes. This study compared inside-out versus all-inside arthroscopic meniscal repair in terms of patient-reported outcome measures (PROMs), failures, return to play, and symptoms.

METHODS

This systematic review was conducted in accordance with the PRISMA guidelines. Two authors independently performed the literature search by accessing the following databases: PubMed, Google Scholar, and Scopus in February 2023. All clinical studies which investigated the outcomes of all-inside and/or inside-out meniscal repair were considered.

RESULTS

Data from 39 studies (1848 patients) were retrieved. The mean follow-up was 36.8 (9 to 120) months. The mean age of the patients was 25.8 ± 7.9 years. 28% (521 of 1848 patients) were women. No difference was found in PROMs: Tegner Activity Scale (P = 0.4), Lysholm score (P = 0.2), and International Knee Document Committee score (P = 0.4) among patients undergoing meniscal repair with all inside or inside-out techniques. All-inside repairs showed a greater rate of re-injury (P = 0.009) but also a greater rate of return to play at the pre-injury level (P = 0.0001). No difference was found in failures (P = 0.7), chronic pain (P = 0.05), reoperation (P = 0.1) between the two techniques. No difference was found in the rate of return to play (P = 0.5) and to daily activities (P = 0.1) between the two techniques.

CONCLUSION

Arthroscopic all-inside meniscal repair may be of special interest in patients with a particular interest in a fast return to sport, while, for less demanding patients, the inside-out suture technique may be recommended. High-quality comparative trials are required to validate these results in a clinical setting.

LEVEL OF EVIDENCE

Level III, systematic review.

Horizontal Cleavage Meniscus Tears: Biomechanics, Indications, Techniques, and Outcomes

» Accounting for up to 24% of all meniscus tears, horizontal cleavage tears (HCTs) are a common pathology orthopaedic practitioners should be comfortable managing.» Historically, HCTs were treated with partial meniscectomy; however, recent studies have demonstrated that these procedures have an adverse biomechanical effect, while HCT repairs restore the knee's natural biomechanics.» Indications for the surgical repair of HCTs remain disputed, but surgery is generally considered for young, active patients and older patients without significant concomitant osteoarthritis.» Early clinical findings surrounding HCT repair are promising. They suggest that this treatment adequately restores meniscus mechanics, leads to good knee functional outcomes, and results in a high likelihood of return to preinjury activity levels.

Autologous blood clots: a natural biomaterial for wound healing

Repair after injury in mammalian tissue involves a complex cascade of events, with the formation of local blood clots being essential for the initial phases of wound healing. As a result, emerging research has sought to harness this biological activity to generate a pro-regenerative biomaterial to speed up wound healing. According to recent studies, “blood clots” created in vitro can be employed as an orthobiologic-based biomaterial for promoting tissue regeneration. Even though such research is still in its early phases, numerous studies show encouraging results that suggest autologous blood clots created in vitro might be a valuable treatment for soft tissue and orthopedic injuries. In this article, we discuss the function of blood clots in physiologic healing, how exogenous material can affect this process, and the most recent clinical research that proposes the use of autologous blood clots as a therapeutically beneficial biomaterial.

Can platelet-rich plasma enhance the effect of meniscus repair? A meta-analysis of randomized controlled trials Platelet-rich plasma and meniscus repair

BACKGROUND

Studies have shown that platelet-rich plasma (PRP) can enhance the effect of meniscus repair, but some studies have suggested different views on the role of PRP.

PURPOSE

To determine whether PRP can enhance the effect of meniscus repair with respect to pain reduction and improved functionality and cure rate in patients with meniscus injury.

METHODS

By searching PubMed, EMBASE, Cochrane Library databases, clinicaltrials.gov, and the CNKI database from their inception till December 1, 2020, we performed a meta-analysis of RCTs reporting the results of the Pain Visual Analog Scale (VAS), the pain of Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm score, the International Knee Documentation Committee (IKDC), healing rate, and adverse events. The risk of bias is assessed using Cochrane's collaborative tools. The summary results are expressed with effect size and 95% confidence interval, and sensitivity were performed.

RESULTS

The meta-analysis included 9 RCTs and 345 patients. In general, compared with the control group, used of PRP during meniscus surgery significantly improved the pain (SMD: -0.95, p < 0.00001,95% CI: -1.22 to -0.69, I2 = 42%) and knee joint function (SMD: 1.00, p = 0.01.95% CI: 0.22 to 1.79, I2 = 89%) of patients with meniscus injury at 6 months after treatment. However, both PRP and non-PRP showed improvements in the pain and knee joint function, with no significant difference between the groups at 1 months and beyond 12 months. The PRP enhancement technique showed benefit in improving the cure rate of meniscus repair (RR:1.44; p < 0.0001, 95% CI: 1.20-1.73). No serious adverse events were reported in any study.

CONCLUSION

As an enhancement program for meniscus repair, PRP is worthy of further consideration in improving the function and pain of patients during the mid-term follow-up after surgery, and PRP can further improve the healing rate of meniscus repair. However, the evidence still needs to be interpreted carefully because of the quantity and quality of the included studies.

Effect of platelet-rich plasma on meniscus repair surgery: A meta-analysis of randomized controlled trials

BACKGROUND

Studies have shown that platelet-rich plasma (PRP) can enhance the effect of meniscus repair, but some studies have suggested different views on the role of PRP. Therefore, a meta-analysis was conducted to determine whether PRP can enhance the effect of meniscus repair with respect to pain reduction and improved functionality and cure rate in patients with meniscus injury.

METHODS

PubMed, EMBASE, Cochrane Library Databases, clinicaltrials.gov, and the CNKI Database were searched from their inception till December 1, 2020. The RCTs reporting the outcomes of the Pain Visual Analog Scale (VAS), Lysholm score, healing rate, and adverse events were included. The risk of bias was assessed using Cochrane collaborative tools. The simulated results were expressed with effect size and 95% confidence interval, and sensitivity and subgroup analysis were performed.

RESULTS

The meta-analysis included 8 RCTs and 431 participants. Compared with the control group, use of PRP during meniscus surgery significantly improved the VAS (SMD: -0.40, P = .002, 95%CI: -0.66 to -0.15) and Lysholm score (MD: 3.06, P < .0001, 95%CI: 1.70-4.42) of meniscus injury, but the PRP showed no benefit in improving the healing rate of meniscus repair (RR: 1.22, P = .06, 95%CI: 0.99-1.51). No serious adverse events were reported in any study.

CONCLUSIONS

PRP is safe and effective in improving the effect of meniscus repair as augment. High quality RCTs with long follow-up and definitive results are needed in the future to confirm the use and efficacy of PRP in meniscus tears.

Arthroscopic Meniscal Repair With Second-Generation Platelet-Rich Fibrin Clot Augmentation

Meniscal tears are among the most common injuries in the knee, and partial as well as total meniscectomy has been advocated as the treatment for meniscal injury. Over the years, the role of the meniscus as a shock absorber, load transmitter, and secondary anterior stabilizer, along with its proprioceptive and lubrication role, has been well established, and meniscal repair is recommended, especially in younger individuals. Factors such as tear location, pattern, chronicity, size, and extent; repair technique; and patient age and habits can influence meniscal repair, and to enhance meniscal healing, a variety of augmentation techniques have been introduced. These include needling, trephination, synovial abrasion, and the use of adjuvants such as platelet-rich plasma, platelet clots, fibrin clots, bone marrow clots, and stem cells. A second-generation platelet derivative called "platelet-rich fibrin" (PRF) has predictable platelet, growth factor, and cell mediator concentrations without using any anticoagulants. We describe a reproducible and simple way to harvest PRF and create and use a PRF clot, along with detailed instructions on how to integrate the clot with a meniscal repair arthroscopically.

The Current Role of Biologics for Meniscus Injury and Treatment

PURPOSE OF REVIEW

There is little doubt that the consensus has changed to favor preservation of meniscal function where possible. Accordingly, the indications for meniscal repair strategies have been refocused on the long-term interest of knee joint health. The development and refinements in surgical technique have been complemented by biological augmentation strategies to address intrinsic challenges in healing capacity of meniscal tissue, with variable effects.

RECENT FINDINGS

A contemporary approach to meniscal healing includes adequate surgical fixation, meniscal and synovial tissue stimulation, and management of the intraarticular milieu. Overall, evidence supporting the use of autogenous or allogeneic cell sources remains limited. The use of FDA-approved medications to effect biologically favorable mechanisms during meniscal healing holds promise. Development and characterization of biologics continue to advance with translational research focused on specific growth factors, cell and tissue behaviors in meniscal healing, and joint homeostasis. Although significant strides have been made in laboratory and pre-clinical studies, translation to clinical application remains challenging. Finally, expert consensus and standardization of nomenclature related to orthobiologics for meniscal preservation will be important for the advancement of this field.

Meniscus treatment: biological augmentation strategies: a narrative review

Objective

An up-to-date description on the biological augmentation strategies for meniscal repair procedures was performed to highlight the main preclinical and clinical evidence available in the literature.

Background

Meniscal repair is a key surgical procedure to preserve as much meniscal tissue as possible to limit the development of knee osteoarthritis (OA). Unfortunately, the results of meniscal repair procedures are not always satisfactory, reporting an overall risk of failure of 25%, likely conditioned due to the poor vascularization of the meniscal tissue. For this reason, several biologic augmentation techniques have been developed to improve the meniscal healing process, ranging from mechanical stimulations to biological products.

Methods

A literature review was conducted on the main biological augmentation procedures combined to the meniscal repair process. A description of the rationale, surgical technique, and preclinical and clinical evidence was performed.

Conclusions

Mechanical stimulations and fibrin clot were the first techniques applied showing several limitations and not exciting results. Recently, platelet-rich plasma (PRP) augmentation to meniscal repair is slowly spreading in the clinical practice. Early evidence from comparative studies showed a significantly lower failure rate in patients treated with PRP augmentation compared with controls. Conversely, the current few and low-level data on mesenchymal stem/stromal cells (MSCs) for meniscal augmentation repair make this a promising but anecdotal topic. Further high-quality clinical studies are needed to support and guide the use of biological strategies for the augmentation of meniscus repair, PRP.

Biological augmentation of meniscal repair: a systematic review

PURPOSE

Orthopedic literature remains divided on the utility of biologic augmentation to optimize outcomes after isolated meniscal repair. The aim of this systematic review is to analyze the clinical outcomes and re-operation rates of biologically augmented meniscal repairs.

METHODS

PubMed, CINAHL, Cochrane, and EMBASE databases were queried in October 2020 for published literature on isolated meniscal repair with biological augmentation. Studies were assessed for quality and risk of bias by two appraisal tools. Patient demographics, meniscal tear characteristics, surgical procedure, augmentation type, post-operative rehabilitation, patient reported outcome measures, and length of follow-up were recorded, reviewed, and analyzed by two independent reviewers.

RESULTS

Of 3794 articles, 18 met inclusion criteria and yielded 537 patients who underwent biologic augmentation of meniscal repair. The biologically augmented repair rates were 5.8-27.0% with PRP augmentation, 0.0-28.5% with fibrin clot augmentation, 0.0-12.9% with marrow stimulation, and 0.0% with stem cell augmentation. One of seven studies showed lower revision rates with augmented meniscal repair compared to standard repair techniques, whereas five of seven found no benefit. Three of ten studies found significant functional improvement of biologically augmented repair versus standard repair techniques and six of ten studies found no difference. There was significant heterogeneity in methods for biologic preparation, delivery, and post-operative rehabilitation protocols.

CONCLUSION

Patients reported significant improvements in functional outcomes scores after repair with biological augmentation, though the benefit over standard repair controls is questionable. Revision rates after biologically augmented meniscal repair also appear similar to standard repair techniques. Clinicians should bear this in mind when considering biologic augmentation in the setting of meniscal repair.

LEVEL OF EVIDENCE

IV.

Current Concepts on Tissue Adhesive Use for Meniscal Repair-We Are Not There Yet: A Systematic Review of the Literature

BACKGROUND

Tissue adhesives (TAs) represent a promising alternative or augmentation method to conventional tissue repair techniques. In sports medicine, TA use has been suggested and implemented in the treatment of meniscal tears. The aim of this review was to present and discuss the current evidence and base of knowledge regarding the clinical usage of TAs for meniscal repair.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic literature search was performed using the PubMed, Embase, and Cochrane Library databases for studies reporting on clinical outcomes of TA usage for meniscal repair in humans in the English language published before January 2020.

RESULTS

Ten studies were eligible for review and included 352 meniscal repairs: 94 (27%) were TA-based repairs and 258 (73%) were combined suture and TA repairs. Concomitant anterior cruciate ligament reconstruction was performed in 224 repairs (64%). All included studies utilized fibrin-based TA. Of the 10 studies, 9 were evidence level 4 (case series), and 8 reported on a cohort of ≤40 meniscal repairs. Rates of meniscal healing were evaluated in 9 of 10 studies, with repair failure seen in 39 repairs (11%).

CONCLUSION

The use of TAs, specifically fibrin-based TAs, for meniscal repair shows good results as either an augmentation or primary repair of various configurations of meniscal tears. However, this review reveals an absence of comparative high-quality evidence supporting the routine use of TAs for meniscal repair and emphasizes the lack of an ideal TA designed for that purpose. Further high-quality research, basic science and clinical, will facilitate the development of new materials and enable testing their suitability for use in meniscal repair.

The transplantation of particulated juvenile allograft cartilage and synovium for the repair of meniscal defect in a lapine model

Background

Synovium has been confirmed to be the primary contributor to meniscal repair. Particulated Juvenile Allograft Cartilage (PJAC) has demonstrated promising clinical effect on repairing cartilage. The synergistic effect of synovium and PJAC transplant on meniscal fibrocartilaginous repair is unclear. We hypothesize that the transplantation of synovium and PJAC synergistically facilitates meniscal regeneration and the donor cells within graft tissues still survive in the regenerated tissue at the last follow up (16 weeks postoperatively).

Methods

The study included 24 mature female rabbits, which were randomly divided into experimental and control groups. A cylindrical full-thickness defect measuring 2.0 ​mm was prepared in the avascular portion of the anterior horn of medial meniscus in both knees. The synovium and PJAC transplant were harvested from juvenile male rabbits (2 months after birth). The experimental group received synovium and PJAC transplant encapsulated with fibrin gel. The control groups received synovium transplant encapsulated with fibrin gel, pure fibrin gel and nothing. The macroscopic, imageological and histological evaluations of repaired tissue were performed at 8 weeks and 16 weeks postoperatively. The in situ hybridization (ISH) of male-specific sex-determining region Y-linked (SRY) gene was performed to detect the transplanted cells.

Results

The regenerated tissue in experimental group showed superior structural integrity, superficial smoothness, and marginal integration compared to control groups at 8 weeks or 16 weeks postoperatively. More meniscus-like fibrochondrocytes filled the repaired tissue in the experimental group, and the matrix surrounding these cell clusters demonstrated strongly positive safranin O and type 2 collagen immunohistochemistry staining. By SRY gene ISH, the positive SRY signal of experimental group could be detected at 8 weeks (75.72%, median) and 16 weeks (48.69%, median). The expression of SOX9 in experimental group was the most robust, with median positive rates of 65.52% at 8 weeks and 67.55% at 16 weeks.

Conclusion

The transplantation of synovium and PJAC synergistically facilitates meniscal regeneration. The donor cells survive for at least 16 weeks in the recipient.

The translational potential of this article

This study highlighted the positive effect of PJAC and synovium transplant on meniscal repair. We also clarified the potential repair mechanisms reflected by the survival of donor cells and upregulated expression of meniscal fibrochondrocytes related genes. Thus, based on our study, further clinical experiments are needed to investigate synovium and PJAC transplant as a possible treatment to meniscal defects.

Histological Analysis of the Wrapping Treatment for Meniscal Horizontal Tears in Rabbits

OBJECTIVE

To investigate meniscal regeneration and prevent cartilage degeneration using wrapping treatment for meniscal horizontal tears that have been difficult to repair in rabbits.

DESIGN

Thirty knees from 15 Japanese white rabbits were divided into the horizontal (horizontal tears) or wrapping (horizontal tears with wrapping treatment) groups. Horizontal tears were created and wrapped with a sheet scaffold containing polyglycolic acid, polylactic acid, and polycaprolactone. The meniscus was stained with Safranin-O/Fast Green and evaluated with modified Pauli scores at 8, 12, and 16 weeks after implantation (n = 5). Cell morphology was determined with hematoxylin and eosin staining. Mature collagen was confirmed with Picrosirius Red staining. Furthermore, immunohistochemical analysis of inducible nitric oxide synthase (iNOS) for inflammation, Ki-67 for proliferation, and type II collagen for regeneration was performed. Medial femoral cartilage was stained with Safranin-O/Fast Green and evaluated with the Osteoarthritis Research Society International score at 8 and 16 weeks.

RESULTS

The wrapping group had significantly better regeneration than the horizontal group, especially at 16 weeks (P < 0.05). Wrapping treatment induced fibrochondrocyte-like cells at 16 weeks. After wrapping treatment, iNOS was overexpressed at 8 weeks, Ki-67 at 8 and 12 weeks, and type II collagen at 16 weeks. Cartilage degeneration in the wrapping group did not progress significantly compared with that in the horizontal group at 16 weeks (P < 0.05).

CONCLUSIONS

Wrapping treatment for meniscal horizontal tears induced meniscal regeneration as the sheet scaffold might induce intrinsic and extrinsic repair. Regaining the meniscal function by the wrapping treatment prevented cartilage degeneration.

Biologic Augmentation during Meniscal Repair

We reviewed the literature regarding utility of biologic augmentation in meniscal repair. We hypothesized that the addition of biologic augmentation during meniscal repair improves postoperative knee function and reduces risk of repair failure. PubMed and Embase databases were systematically searched. Included studies were clinical studies in humans, published in English, and reported use of biologic augmentation techniques in addition to meniscal repair (including platelet-rich plasma [PRP], fibrin clot, bone marrow stimulation, meniscal wrapping, and bioscaffolds) for treatment of knee meniscal tears. Outcome measures included repair failure, repeat knee arthroscopic surgery, and magnetic resonance imaging), visual analog scale for pain, the International Knee Documentation Committee questionnaire, the Western Ontario and McMaster Universities Osteoarthritis Index Lysholm's Knee Scoring Scale, and the Knee Injury and Osteoarthritis Outcome Score. Study quality was assessed using the modified Coleman methodology score. Nineteen studies reported repair of 1,092 menisci including six studies that investigated fibrin clot augmentation, five studies that investigated PRP augmentation, three studies that investigated bone marrow stimulation augmentation, two studies that used meniscal wrapping augmentation, and three studies that used other techniques. The level of evidence ranged from I to IV and mean modified Coleman methodology score was 43 (range: 17-69), with higher scores noted in studies completed in recent years. PRP and bone marrow stimulation augmentation appear to decrease risk of failure in patients undergoing isolated meniscal repair but do not improve knee symptom scores. Fibrin clot and trephination augmentation techniques do not have sufficient evidence to support decreased failure risk at this time. Meniscal wrapping augmentation and scaffold implantation augmentation appear to be an attractive option to meniscectomy in complicated tears that are not candidates for repair alone, but further confirmatory studies are needed to support initial data. Evidence supporting augmentation of meniscal repair is limited at this time but suggests that the highest likelihood for effectiveness of augmentation is in the settings of isolated meniscal repair or meniscal repairs that would normally not be amenable to repair.

Fibrin Clot Augmented Repair of Longitudinal Tear of Medial Meniscus

Repair of meniscus injuries always posed a significant problem, especially in relatively avascular zones. Several methods to augment the repair were devised, but only a few had convincing results. Fibrin clot augmentation is one of the augmentation procedures that shows good promise in this premise. The major hurdle to it is difficulty in delivering into the meniscus tear under constant irrigation during arthroscopic procedures. This article presents a simple and unique way to prepare and transfer a fibrin clot into a meniscal tear in a step-by-step manner.

Nonoperative and Operative Soft-Tissue and Cartilage Regeneration and Orthopaedic Biologics of the Knee: An Orthoregeneration Network (ON) Foundation Review

Orthoregeneration is defined as a solution for orthopedic conditions that harnesses the benefits of biology to improve healing, reduce pain, improve function, and optimally, provide an environment for tissue regeneration. Options include: drugs, surgical intervention, scaffolds, biologics as a product of cells, and physical and electro-magnetic stimuli. The goal of regenerative medicine is to enhance the healing of tissue after musculoskeletal injuries as both isolated treatment and adjunct to surgical management, using novel therapies to improve recovery and outcomes. Various orthopaedic biologics (orthobiologics) have been investigated for the treatment of pathology involving the knee, including symptomatic osteoarthritis and chondral injuries, as well as injuries to tendon, meniscus, and ligament, including the anterior cruciate ligament. Promising and established treatment modalities include hyaluronic acid (HA) in liquid or scaffold form; platelet-rich plasma (PRP); bone marrow aspirate (BMA) comprising mesenchymal stromal cells (MSCs), hematopoietic stem cells, endothelial progenitor cells, and growth factors; connective tissue progenitor cells (CTPs) including adipose-derived mesenchymal stem cells (AD-MSCs) and tendon-derived stem cells (TDSCs); matrix cell-based therapy including autologous chondrocytes or allograft; vitamin D; and fibrin clot. Future investigations should standardize solution preparations, because inconsistent results reported may be due to heterogeneity of HA, PRP, BMAC, or MSC preparations and regimens, which may inhibit meaningful comparison between studies to determine the true efficacy and safety for each treatment.

Meniscal repair: The current state and recent advances in augmentation

Meniscal injuries represent one of the most common orthopedic injuries. The most frequent treatment is partial resection of the meniscus, or meniscectomy, which can affect joint mechanics and health. For this reason, the field has shifted gradually towards suture repair, with the intent of preservation of the tissue. "Save the Meniscus" is now a prolific theme in the field; however, meniscal repair can be challenging and ineffective in many scenarios. The objectives of this review are to present the current state of surgical management of meniscal injuries and to explore current approaches being developed to enhance meniscal repair. Through a systematic literature review, we identified meniscal tear classifications and prevalence, approaches being used to improve meniscal repair, and biological- and material-based systems being developed to promote meniscal healing. We found that biologic augmentation typically aims to improve cellular incorporation to the wound site, vascularization in the inner zones, matrix deposition, and inflammatory relief. Furthermore, materials can be used, both with and without contained biologics, to further support matrix deposition and tear integration, and novel tissue adhesives may provide the mechanical integrity that the meniscus requires. Altogether, evaluation of these approaches in relevant in vitro and in vivo models provides new insights into the mechanisms needed to salvage meniscal tissue, and along with regulatory considerations, may justify translation to the clinic. With the need to restore long-term function to injured menisci, biologists, engineers, and clinicians are developing novel approaches to enhance the future of robust and consistent meniscal reparative techniques.

Intrasubstance degeneration of medial meniscus horizontal cleavage tear in young patients is associated with increased joint line obliquity in the coronal plane of the knee

PURPOSE

To evaluate the effect of joint line obliquity of the knee on intrasubstance degeneration of isolated medial meniscus horizontal cleavage tear (HCT) in young patients.

METHODS

Sixty knees of 50 patients aged < 40 years (mean age, 33.3 ± 5.5 years old), who underwent arthroscopic partial meniscectomy (APM) for HCT, were retrospectively reviewed. The radiologic parameters of alignment, including mechanical hip-knee-ankle (mHKA) angle, posterior tibial slope, and joint line obliquity, were measured on preoperative long-standing whole-leg radiographs. The patients were classified into two groups, simple horizontal type (type 1) and complicated type (type 2), according to the presence of diffuse intrasubstance degeneration of the meniscus on preoperative magnetic resonance imaging. The risk factors for intrasubstance degeneration of HCT were analyzed using multiple logistic regression analysis. Medial joint space width (JSW) on weight-bearing 45° flexion posteroanterior radiographs and the mHKA were measured to evaluate the radiographic outcomes. The clinical outcomes were evaluated using the modified Lysholm score. Among patients followed-up for > 5 years, the clinical and radiologic outcomes were compared between the two groups.

RESULTS

The joint line obliquity was significantly greater in the type 2 group than in the type 1 group (2.9 ± 1.3 vs. 0.9 ± 1.4, P < 0.001), and a significant risk factor for diffuse intrasubstance degeneration (P < 0.001; odds ratio, 2.88; 95% confidence interval, 1.27-6.54). The relative changes in the JSW in the type 2 group were greater than those in the type 1 group during the mean follow-up period of 7.9 ± 2.5 years (26% vs 10%, P = 0.045). The modified Lysholm score was not significantly different between the two groups (n.s).

CONCLUSION

The diffuse intrasubstance degeneration of medial meniscus HCTs in young patients is associated with increased joint line obliquity of the knee joints. The radiologic outcomes after APM were inferior in the patients with diffuse intrasubstance degeneration. However, the clinical outcomes were not different during the mid-term follow-up.

LEVEL OF EVIDENCE

Level III.

Biologic Augmentation Reduces the Failure Rate of Meniscal Repair: A Systematic Review and Meta-analysis

Background

Clinical results after isolated meniscal repair are not always satisfactory, with an overall failure rate of around 25%. To improve the success rate of meniscal repair, different biologic augmentation techniques have been introduced in clinical practice, but their real efficacy is still controversial.

Purpose/Hypothesis

To evaluate the safety, clinical results, and failure rate of biologic augmentation techniques for meniscal repair. The hypothesis was that biologic augmentation would improve the results of meniscal repair.

Study Design

Systematic review and meta-analysis of comparative studies.

Methods

A systematic review of the literature was performed in March 2020 of 3 electronic databases (PubMed, Scopus, and the Cochrane Library) regarding meniscal repair combined with biologic augmentation techniques. Articles combining biologic augmentation with other surgical procedures besides meniscal suture were excluded. The quality of the included studies was assessed using a modified Coleman Methodology Score, and the risk of bias was evaluated using the ROBINS-I (Risk of Bias in Non-randomized Studies of Interventions) and the RoB 2.0 (Revised Tool for Risk of Bias in Randomized Trials) for nonrandomized and randomized controlled trials, respectively.

Results

A total of 11 studies were included in the qualitative analysis: platelet-rich plasma (PRP) augmentation in 6 comparatives studies, fibrin clot augmentation in 2 case series, and mesenchymal stem cells augmentation in 2 case series and 1 case report. One severe adverse event of septic arthritis was reported for PRP 1 month after surgery. The quality of evidence evaluated with the modified Coleman Methodology Score was low overall. Five studies reporting on 286 patients (111 PRP augmentation, 175 control) were included in the quantitative synthesis. A significantly lower risk of failure was documented in the PRP augmentation group as compared with the control group: 9.9% (4.5%-19.1%) versus 25.7% (12.7%-38.7%) (P < .0005).

Conclusion

The literature on biologic meniscal augmentation is recent and scarce. Only a few comparative trials are available, all focusing on the potential of PRP. The meta-analysis documented that PRP is safe and useful in improving the survival rate, with a 9.9% rate of failure versus 25.7% for the control group. Further high-level studies are needed to confirm these findings and identify the most effective biologic augmentation strategy to improve the outcome of meniscal repair.

Platelet-Rich Plasma Augmentation for Isolated Arthroscopic Meniscal Repairs Leads to Significantly Lower Failure Rates: A Systematic Review of Comparative Studies

Background:

Studies have reported relatively high failure rates of isolated meniscal repairs. Platelet-rich plasma (PRP) has been suggested as a way to increase growth factors that enhance healing.

Purpose:

To compare (1) meniscal repair failures and (2) patient-reported outcomes after isolated arthroscopic meniscal repair augmented with and without PRP.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

A systematic review was performed using the PRISMA (Preferred Reporting Items for Systematic Meta-Analyses) guidelines. Multiple databases were searched for studies that compared outcomes of isolated arthroscopic meniscal repair augmented with PRP versus without PRP in human patients. Failures and patient-reported outcome scores were reported for each study and compared between groups. Study heterogeneity was assessed using I² for each outcome measure before meta-analysis. Study methodological quality was analyzed. Continuous variable data were reported as mean and standard deviation from the mean. Categorical variable data were reported as frequency with percentage. All P values were reported with significance set at P < .05.

Results:

Five articles were analyzed (274 patients [110 with PRP and 164 without PRP]; 65.8% male; mean age, 29.1 ± 4.6 years; mean follow-up, 29.2 ± 22.1 months). The risk of meniscal repair failure ranged from 4.4% to 26.7% for PRP-augmented repairs and 13.3% to 50.0% for repairs without PRP. Meniscal repairs augmented with PRP had significantly lower failure rates than repairs without PRP (odds ratio, 0.32; 95% CI, 0.12-0.90; P = .03). One of the 5 studies reported significantly higher outcomes in the PRP-augmented group versus the no-PRP group for the International Knee Documentation Committee (IKDC), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Knee injury and Osteoarthritis Outcome Score (KOOS) (P < .05 for all). The remaining 4 studies reported no significant difference between groups with regard to outcomes for the IKDC, Lysholm knee scale, visual analog scale for pain, or Tegner activity level.

Conclusion:

Although the studies were of mostly of low quality, isolated arthroscopic meniscal repairs augmented with PRP led to significantly lower failure rates (10.8% vs 27.0%; odds ratio, 0.32; P = .03) as compared with repairs without PRP. However, most studies reported no significant differences in patient-reported outcomes.

Successful treatment of degenerative medial meniscal tears in well-aligned knees with fibrin clot implantation

PURPOSE

The purpose of this study was to examine the results of meniscal repair performed for symptomatic degenerative medial meniscal tears.

METHODS

Twenty-four knees in 24 patients with symptomatic degenerative medial meniscal tears (mostly complex horizontal tears) who underwent isolated arthroscopic repair combined with autologous fibrin clot implantation were included in this study. The patients were followed up for a minimum of 2 years. The overall clinical outcome was evaluated using the Lysholm score, while the activity level was graded on the Tegner Activity Scale. The assessment of healing status at the repair site was based on clinical signs/symptoms and follow-up MRI examination results. In addition, the effects of the patient's clinical and radiological factors on healing of the repaired menisci were analyzed.

RESULTS

The mean age of the study subjects was 47.0 ± 8.1 years with a mean follow-up period of 39.3 ± 11.6 months. The Lysholm score significantly improved after surgery (P < 0.01). During the follow-up period, meniscal repairs were deemed to have failed in 6 of the 24 knees (25%). In the analysis of factors influencing meniscal healing, varus deformity (% of mechanical axis < 30%) was identified in all knees in the repair failure group, and the presence of varus deformity was shown to be a significant risk factor correlated with repair failure, while other factors did not significantly influence the healing status.

CONCLUSIONS

The short-term follow-up results showed that arthroscopic repair of degenerative medial meniscal tears combined with fibrin clot implantation attained clinical healing in 18 of 24 knees (75%) of patients, while 6 of the 24 knees (25%) of patients experienced clinical failure. The presence of varus deformity negatively affects the healing rate. In well-aligned knees, degenerative medial meniscal tears are successfully treated by isolated repair with fibrin clot implantation.

LEVEL OF EVIDENCE

IV.

Patient Outcomes After Horizontal Cleavage Tear Repair: A Systematic Review

PURPOSE

To analyze the clinical outcomes and survivorship of meniscal horizontal cleavage tear (HCT) repairs with hopes of guiding future treatment decisions.

METHODS

Standard systematic review methodology was used. A comprehensive search of PubMed was conducted on June 1, 2019. The inclusion criteria were articles that were published in English, involved human subjects, and reported on at least 1 outcome after repair of HCTs. The exclusion criteria included technique guides and reviews, studies without full text available, and studies with HCT outcomes not separated from other repair groups. Effect heterogeneity was determined using the I² measure. Forest plots were created in addition to a random-effects model to show the results.

RESULTS

The systematic review yielded 19 studies evaluating 289 knees in a total of 273 patients. At most recent follow-up, there was a high probability of return to sport (93.1% [67 of 72]). Overall, 74% of patients (67 of 90) were symptom free at last follow-up, and 80% expressed satisfaction with their overall result (80 of 100). The most frequently reported subjective outcome was the Lysholm score, which improved from a preoperative study range of 48 to 79 (I² = 20.7%, P = .283) to a postoperative study range of 56 to 99 (I² = 49%, P = .081). The next most commonly reported was the International Knee Documentation Committee subjective score, which improved from a preoperative study range of 16 to 49 (I² = 47.7%, P = .125) to a postoperative study range of 72 to 95 (I² = 0%, P = .660). An overall 11.7% reported risk of reoperation was found, with most cases involving revision meniscectomy. Rates of complications beyond fixation failure were overall very low, with infrequent reports of septic arthritis and transitory dysesthesia.

CONCLUSIONS

The short- to intermediate-term results of repair of HCTs are comparable to prior studies. Survivorship is comparable to repairs of other types of meniscal tears with high rates of return to sport and low complication rates.

LEVEL OF EVIDENCE

Level IV, systematic review of Level I-IV studies.

Platelet-Rich Plasma Augmentation in Meniscal Repair Surgery: A Systematic Review of Comparative Studies

PURPOSE

To systematically review the literature on meniscal repair surgery and assess functional and radiographic outcomes of platelet-rich plasma (PRP)-augmented repair compared with standard repair techniques.

METHODS

A systematic review of the literature was completed according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines using the PubMed, MEDLINE, Embase, and Cochrane databases. The inclusion criteria included all human studies testing PRP augmentation of meniscal repair written in the English language. All cadaveric, animal, and basic science studies were excluded from review. The quality of the included publications was assessed prior to data extraction through the Jadad score. Risk of bias was further determined by Methodological Index for Non-randomized Studies (MINORS) and Cochrane risk-of-bias assessments. Heterogeneity in outcomes reported across studies was evaluated using I² statistic calculations.

RESULTS

A total of 5 studies (1 with Level I evidence; 1, Level II; and 3, Level III) met the inclusion criteria for this review, all comparing PRP augmentation of meniscal repair surgery versus meniscal repair with no augmentation. Overall quality and risk of bias in the included studies varied substantially (Jadad score, 1-5; Methodological Index for Non-randomized Studies score, 7-18). Three comparative studies found no significant difference in outcome or failure, whereas the other two showed a significant improvement in PRP-augmented repairs at final follow-up. Two studies assessed healing with postoperative magnetic resonance imaging or second-look arthroscopy, with both showing significantly improved outcomes in the PRP-treated groups (P < .01 and P = .048). PRP preparation techniques and composition differed among all studies and were inconsistently reported.

CONCLUSIONS

In early and limited investigations, there is insufficient evidence to support PRP augmentation of meniscal repair surgery improving functional and radiographic outcomes and resulting in lower failure rates compared with standard repair techniques. There is considerable heterogeneity in the reporting and preparation of PRP used for augmentation.

LEVEL OF EVIDENCE

Level III, systematic review of Level I to III studies.

The repair of horizontal cleavage tears yields higher complication rates compared to meniscectomy: a systematic review

PURPOSE

Horizontal cleavage tears of the meniscus (HCTs) are primarily degenerative in nature, and, however, can be the result of trauma. Such tears account for 12-35% of all tear patterns and can be treated by partial meniscectomy or arthroscopic repair. The purpose of this review was to systematically assess the outcomes and complications for patients undergoing the surgical treatment of HCTs.

METHODS

This review has been conducted according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-analyses. The electronic databases PubMed, MEDLINE, and EMBASE were searched from data inception to December 30, 2018 for articles addressing the surgical treatment of HCTs. The Methodological Index for Non-randomized Studies was used to assess study quality. Data are presented descriptively.

RESULTS

Overall, 23 studies were identified, comprising of 702 patients (708 knees) with a mean age of 36.6 ± 9.9 years and a mean follow-up of 33.6 ± 19.6 months. The majority of patients were treated with a partial meniscectomy (59.0%), followed by repair (32.8%) and total meniscectomy (8.2%). Both meniscectomy and repair patients had improvements which surpassed minimal clinically important differences with regard to clinical (e.g. pain, function, daily living) and radiographic outcomes. The overall complication rate was 5.1%, primarily involving patients undergoing meniscal repair (12.9% of all knees undergoing a repair).

CONCLUSION

Although meniscal repair theoretically may provide improvement in biomechanical loading, patients undergoing repair had higher complication rates than those undergoing partial meniscectomy. Clinicians should consider the available implants in determining which tear patterns to repair and future studies with long-term follow-up are needed to investigate complications (e.g. secondary meniscal procedures) as well as the potential for delay in the development of osteoarthritis.

LEVEL OF EVIDENCE

Level IV.

Fibrin Clots Maintain the Viability and Proliferative Capacity of Human Mesenchymal Stem Cells: An In Vitro Study

BACKGROUND

Augmentation of soft-tissue repairs with an autologous fibrin clot has been used clinically for nearly four decades; however, fibrin clots tend to produce an abundance of scar tissue, which is known to inhibit soft-tissue regeneration. Mesenchymal stem cells (MSCs) embedded in fibrin clots before repair could reduce scar tissue deposition and facilitate soft-tissue regeneration. To our knowledge, no published studies have directly evaluated the viability or bioactivity of MSCs in fresh human fibrin clots over time. The purpose of this study was to evaluate the viability and bioactivity of human MSCs inside human fibrin clots over time in nutritive and non-nutritive culture media.

QUESTIONS/PURPOSES

We hypothesized that human MSCs would (1) be captured inside fibrin clots and retain their proliferative capacity, (2) remain viable for at least 7 days in the fibrin clots, (3) maintain their proliferative capacity for at least 7 days in the fibrin clots without evidence of active apoptosis, and (4) display similar viability and proliferative capacity when cultured in a non-nutritive medium over the same time periods.

METHODS

Twelve patients (mean age 33.7 years; range 4-72 years) who underwent elective knee surgery were approached between February 2016 and October 2017; all patients agreed to participate and were enrolled. MSCs isolated from human skeletal muscle and banked after prior studies were used for this analysis. On the day of surgery and after expansion of the MSC population, 3-mL aliquots of phosphate-buffered saline containing approximately 600,000 labeled with anti-green fluorescent protein (GFP) antibodies were transported to the operating room, mixed in 30 mL of venous blood from each enrolled patient, and stirred at 95 rpm for 10 minutes to create MSC-embedded fibrin clots. The fibrin clots were transported to the laboratory with their residual blood for analysis. Eleven samples were analyzed after exclusion of one sample because of a processing error. MSC capture was qualitatively demonstrated by enzymatically digesting half of each clot specimen, thus releasing GFP-positive MSCs into culture. The released MSCs were allowed to culture for 7 days. Manual counting of GFP-positive MSCs was performed at 2, 3, 4, and 7 days using an inverted microscope at 100 x magnification to document the change in the number of GFP-positive MSCs over time. The intact remaining half of each clot specimen was immediately placed in proliferation media and allowed to culture for 7 days. On Days 1, 2, 3, 4, and 7, a small portion of the clot was excised, flash-frozen, cryosectioned (8-μm thickness), and immunostained with antibodies specific to GFP, Ki67 (indicative of active proliferation), and cleaved caspase-3 ([CC3]; indicative of active apoptosis). Using an inverted microscope, we obtained MSC cell counts manually at time zero and after 1, 2, 3, 4, and 7 days of culture. Intact fresh clot specimens were immediately divided in half; one half was placed in nutritive (proliferation media) and the other was placed in non-nutritive (saline) media for 1, 2, 3, 4, and 7 days. At each timepoint, specimens were processed in an identical manner as described above, and a portion of each clot specimen was excised, immediately flash-frozen with liquid nitrogen, cryosectioned (8-μm thickness), and visualized at 200 x using an inverted microscope. The numbers of stain-positive MSCs per field of view, per culture condition, per timepoint, and per antibody stain type were counted manually for a quantitative analysis. Raw data were statistically compared using t-tests, and time-based correlations were assessed using Pearson's correlation coefficients. Two-tailed p values of less than 0.05 (assuming unequal variance) were considered statistically significant.

RESULTS

Green fluorescence, indicative of viable GFP-positive MSCs, was absent in all residual blood samples after 48 hours of culturing; GFP-positive MSCs were visualized after enzymatic digestion of clot matrices. The number of GFP-positive MSCs per field of view increased between the 2-day and 7-day timepoints (mean 5.4 ± 1.5; 95% confidence interval, 4.7-6.1 versus mean 17.0 ± 13.6; 95% CI, 10.4-23.5, respectively; p = 0.029). Viable GFP-positive MSCs were present in each clot cryosection at each timepoint up to 7 days of culturing (mean 6.2 ± 4.3; 95% CI, 5.8-6.6). There were no differences in MSC counts between any of the timepoints. There was no visible evidence of GFP +/CC3 + double-positive MSCs. Combining all timepoints, there were 0.34 ± 0.70 (95% CI, 0.25-0.43) GFP+/Ki67+ double-positive MSCs per field of view. The mitotic indices at time zero and Day 7 were 7.5% ± 13.4% (95% CI, 3.0%-12.0%) and 7.2% ± 14.3% (95% CI, 3.3%-12,1%), respectively (p = 0.923). There was no visible evidence of GFP +/CC3 + double-positive MSCs (active apoptosis) at any timepoint. For active proliferation in saline-cultured fibrin clots, we found averages of 0.1 ± 0.3 (95% CI, 0.0-0.2) and 0.4 ± 0.9 (95% CI, 0.0-0.8) GFP/Ki67 double-positive MSCs at time zero and Day 7, respectively (p = 0.499). The mitotic indices in saline culture at time zero and Day 7 were 2.9% ± 8.4% (95% CI, 0.0%-5.8%) and 9.1% ± 20.7% (95% CI, 1.2%-17.0%; p = 0.144). There was no visible evidence of GFP +/CC3 + double-positive MSCs (active apoptosis) at any timepoint in either culturing condition.

CONCLUSION

These preliminary in vitro results show that human MSCs mixed in unclotted fresh human venous blood were nearly completely captured in fibrin clots and that seeded MSCs were capable of maintaining their viability, proliferation capacity, and osteogenic differentiation capacity in the fibrin clot for up to 7 days, independent of external sources of nutrition.

CLINICAL RELEVANCE

Fresh human fibrin clots have been used clinically for more than 30 years to improve soft-tissue healing, albeit with scar tissue. Our results demonstrate that allogenic human MSCs, which reduce soft-tissue scarring, can be captured and remain active inside human fibrin clots, even in the absence a nutritive culture medium.

Meniscal tear morphology independently affects pain relief following arthroscopic partial meniscectomy in middle-aged patients

PURPOSE

To analyze the influence of meniscal tear pattern on clinical outcomes following arthroscopic partial meniscectomy in middle-aged patients with medial meniscal tears.

METHODS

A total of 123 patients (130 knees) aged ≥ 50 years who underwent arthroscopic partial meniscectomy for medial meniscal tears were evaluated. Inclusion criteria were none to moderate medial knee osteoarthritis [Kellgren-Lawrence (KL) grade ≤ 3] and a minimum of 2-year follow-up (median 4.6 years; range 2.1-8.0 years). Meniscal tears observed during arthroscopic examination were classified into six types: radial tear of the middle segment, posterior root tear, horizontal tear of the posterior segment, flap tear, minor tear, and complex tear. Postoperative outcomes were classified into effective (group 1) and non-effective (group 2) according to the pain relief administered 1 month postoperatively and at the final follow-up. Demographic variables, KL grade, type of meniscal tear, and postoperative follow-up period were evaluated.

RESULTS

Forty knees (38%) were classified into group 1. Of the six types of tears, radial tear of the middle segment [odds ratio (OR) 4.1, 95% confidence interval (CI) 1.1-20.9] and flap tear (OR 12.9, 95% CI 1.8-140.7) were significant predictors of good outcome on multivariate logistic regression analysis.

CONCLUSIONS

In middle-aged patients with medial meniscal tears, radial tear of the middle segment was independently associated with less pain following arthroscopic meniscectomy. Arthroscopic partial meniscectomy may be indicated in patients with radial tear if conservative treatment fails.

LEVEL OF EVIDENCE

Case-control study, Level III.

One-Third of Meniscal Tears Are Repairable: An Epidemiological Study Evaluating Meniscal Tear Patterns in Stable and Unstable Knees

PURPOSE

To analyze, in a long series of patients with knee injuries, the meniscal tear patterns in both stable and unstable knees to ascertain the exact proportion of such injuries that could have been repaired.

METHODS

A descriptive cross-sectional study was undertaken by reviewing the clinical reports of arthroscopic knee operations carried out in 1 hospital. A total of 2,066 consecutive patients were included in the study. An analysis of clinical and anatomical data of knee lesions, including the shape of the meniscal tears and the surrounding injuries, was performed.

RESULTS

Out of all meniscal tears, 34.9% were found to be repairable, a figure that rose to 55.6% in those tears accompanied by anterior cruciate ligament injuries; 37% of meniscal tears in male patients were repairable, and 28% in their female counterparts; 38.2% of medial meniscal tears were repairable and 30.6% in their lateral counterparts. The most frequently encountered injury was the complex tear (46.9%).

CONCLUSIONS

Our study concludes that, according to current standard indications, 34.9% of all meniscal injuries offer the potential for repair. Where the injury is also accompanied by anterior cruciate ligament damage, the proportion of repairable tears rises to 55.6%. This information should increase the interest for meniscal preservation in the future.

LEVEL OF EVIDENCE

Level IV, case series.

Meniscal repair associated with a partial meniscectomy for treating complex horizontal cleavage tears in young patients may lead to excellent long-term outcomes

INTRODUCTION

While open repair of horizontal meniscal tears in young active patients has shown good results at mid- and long-term follow-up, complex horizontal tears (cleavage associated with meniscal flaps) are often treated by arthroscopic subtotal meniscectomy. The aim of this study was to evaluate long-term outcomes after arthroscopic removal of meniscal flaps associated with an open meniscal repair for treating complex lesions in young active patients. The hypothesis was that this salvage procedure would be efficient in such rare cases.

METHODS

Fourteen patients underwent an arthroscopic partial meniscectomy associated with an open meniscal repair to treat a painful complex horizontal meniscal cleavage between 2005 and 2010. There were two females and 12 males with a median age of 28.4 years (range 15-48 years). Patients were assessed by KOOS and IKDC scores, return to sport and the need for a secondary meniscectomy.

RESULTS

Thirty patients were evaluated at a median follow-up of 8.5 years (range 7-12 years). One patient required revision of a partial meniscectomy and one other a meniscal replacement (15% failure rate). All other patients showed improvement with regard to their symptoms and returned to sports, ten (91%) of them at the same level. The mean IKDC subjective score was 86.1 (± 10.9). The mean KOOS scores were: pain 91.4 (± 7.5), symptoms 91.4 (± 10.2), daily activity 97.1 (± 4), sports 84.4 (± 20.7) and quality of life 84 (± 14.2). For six patients, scores at median follow-up of 2.6 years were available and compared to newly obtained data. IKDC score at 8.6 years follow-up was not significantly different. KOOS scores for daily activity and sports were maintained.

CONCLUSIONS

Even in the presence of a complex lesion, horizontal cleavage can be repaired in young patients with good subjective and objective outcomes and a low rate of long-term failure as with other meniscal lesions in young active patients.

LEVEL OF EVIDENCE

IV.

Possible reparative effect of low-intensity pulsed ultrasound (LIPUS) on injured meniscus

Menisci are a pair of crescent-shaped fibrocartilages, particularly of which their inner region of meniscus is an avascular tissue. It has characteristics similar to those of articular cartilage, and hence is inferior in healing. We previously reported that low-intensity pulsed ultrasound (LIPUS) treatment stimulates the production of CCN2/CTGF, a protein involved in repairing articular cartilage, and the gene expression of major cartilage matrices such as type II collagen and aggrecan in cultured chondrocytes. Therefore, in this present study, we investigated whether LIPUS has also favorable effect on meniscus cells and tissues. LIPUS applied with a 60 mW/cm² intensity for 20 min stimulated the gene expression and protein production of CCN2 via ERK and p38 signaling pathways, as well as gene expression of SOX9, aggrecan, and collagen type II in human inner meniscus cells in culture, and slightly stimulated the gene expression of CCN2 and promoted the migration in human outer meniscus cells in culture. LIPUS also induced the expression of Ccn2, Sox9, Col2a1, and Vegf in rat intact meniscus. Furthermore, histological evaluations showed that LIPUS treatment for 1 to 4 weeks promoted healing of rat injured lateral meniscus, as evidenced by better and earlier angiogenesis and extracellular matrix synthesis. The data presented indicate that LIPUS treatment might prevent meniscus from degenerative change and exert a reparative effect on injured meniscus via up-regulation of repairing factors such as CCN2 and that it might thus be useful for treatment of an injured meniscus as a non-invasive therapy.

Modern treatment of meniscal tears

The complex ultrastructure of the meniscus determines its vital functions for the knee, the lower extremity, and the body.

The most recent concise, reliable, and valid classification system for meniscal tears is the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) Classification, which takes into account the subsequent parameters: tear depth, tear pattern, tear length, tear location/rim width, radial location, location according to the popliteal hiatus, and quality of the meniscal tissue.

It is the orthopaedic surgeon’s responsibility to combine clinical information, radiological images, and clinical experience in an effort to individualize management of meniscal tears, taking into account factors related to the patient and lesion.

Surgeons should strive not to operate in most cases, but to protect, repair or reconstruct, in order to prevent early development of osteoarthritis by restoring the native structure, function, and biomechanics of the meniscus.

Currently, there are three main methods of modern surgical management of meniscus tears: arthroscopic partial meniscectomy; meniscal repair with or without augmentation techniques; and meniscal reconstruction. Meniscus surgery has come a long way from the old slogan, “If it is torn, take it out!” to the currently accepted slogan, “Save the meniscus!” which has guided evolving modern treatment methods for meniscal tears. This last slogan will probably constitute the basis for newer alternative biological treatment methods in the future.

Cite this article: EFORT Open Rev 2018;3 DOI: 10.1302/2058-5241.3.170067.

The use of platelet-rich fibrin with platelet-rich plasma support meniscal repair surgery

Introduction

Platelet-rich fibrin (PRF) is the only autologous blood product that releases growth factors and has scaffolding properties. We hypothesized that the use of PRF and Platelet-rich plasma (PRP) would improve operative results, including the recovery of function and repaired meniscus.

Materials and Methods

Seventeen patients underwent arthroscopic meniscus repair with PRF and PRP (PRF group) using our novel device for the injection of the PRF into the joint. Another five patients as a control group underwent meniscal repair without PRF and PRP (non-PRF group). The groups were compared in terms of clinical results (Tegner Activity Level Scale, Lysholm Knee Scoring Scale, and International Knee Documentation Committee [IKDC] scores) and changes in magnetic resonance imaging (MRI) findings before surgery and 6 months after surgery.

Results

The Lysholm and IKDC scores improved in all patients postoperatively. However, there was no significant differencies in the postoperative score between the PRF group and the non-PRF group. Follow-up MRI findings did not clearly show improvements.

Conclusions

PRF and PRP are autologous, safe, and cost-effective sources of growth factors. Therefore, we propose a new application of PRF and PRP for autologous transplantation in meniscus repair surgery.

The role of meniscal repair for prevention of early onset of osteoarthritis

BACKGROUND

The meniscus plays an important role in the integrity of the knee joint. Therefore, meniscus tissue preserving techniques for the therapy of meniscus injuries seem to be reasonable. One of the important questions is whether meniscal repair can prevent the knee joint from early onset of osteoarthritis.

METHODS

According to the review of the current literature, the principles of a successful meniscal repair are explained and the functional outcome and its impact on the prevention of osteoarthritis are analyzed in this article.

RESULTS

Current data show a positive impact of a successful meniscus repair on the functional outcome in long-term. By this a protective effect on the development of osteoarthritis via the repair of meniscus lesions to restore the meniscus integrity can be confirmed. However, higher rates of re-operations in context to meniscus suturing have to be considered.

CONCLUSION

Due to the improved functional outcomes as well as preventive effect on the development of osteoarthritis within the knee joint in long-term, it is of importance to preserve as much meniscus tissue as possible in meniscus therapy. Patients previously have to be informed about the higher revision rate in context to meniscus suturing.

Repair of a Chronic Large Meniscal Defect With Implantation of Autogenous Meniscal Fragments Using a Tubular-Shaped Fibrin Clot

We present a technique to implant autogenous meniscal fragments using a fibrin clot to repair a large degenerative meniscal defect. A total of 25 mL of the patient's blood is agitated for 10 minutes using a stainless steel swizzle stick in a sterile glass syringe. The elastic fibrin clot subsequently adheres to the stick in a tubular manner. Using arthroscopic debridement, native meniscal tissue is resected. The meniscal fragments are packaged into the tubular-shaped fibrin clot, and the tube is tied at both ends using 4-0 absorbable sutures. A repair suture is prepared using the inside-out meniscal repair device and woven into the margins of the tubular-shaped fibrin clot. The packaged graft with the tubular-shaped fibrin clot is placed with a horizontal suture across both edges of the meniscal defect and secured with a supplemental vertical suture using an all-inside meniscal repair device. Follow-up arthroscopy performed 6 months postoperatively reveals regeneration of meniscus-like tissue. It is ideal to treat large degenerative defects with meniscal preservation, and the present procedure has the advantage of tissue regeneration with native meniscal tissue and growth factors obtained from the fibrin clot using a simple technique. This method could prove helpful in patients with degenerative meniscal defects.

Adipose Stem Cells Incorporated in Fibrin Clot Modulate Expression of Growth Factors

PURPOSE

To evaluate the platelet capture rate of whole blood fibrin clots and the expression, secretion, and retention of the growth factors vascular endothelial growth factor (VEGF), platelet-derived growth factor (PDGF), and basic fibroblast growth factor (bFGF) from fibrin clots and to determine how these levels may be modulated by allogeneic adipose-derived stem cells (ASCs).

METHODS

Whole blood from 10 human volunteers was transferred to a clotting device and the platelet capture rate determined. Two experimental conditions and 1 control were evaluated over 2 weeks in vitro. Clots made from human whole blood without ASCs, clot(-)ASC, were compared with clots with ASCs incorporated, clot(+)ASC, and a control group of synthetic polyethylene glycol gels with ASCs incorporated, control(+)ASCs. All conditions were examined for secretion and retention of VEGF, PDGF, and bFGF via enzyme-linked immunosorbent assay and immunohistochemistry. The analysis of platelet retention for clots made with this device was performed.

RESULTS

Enzyme-linked immunosorbent assay analysis showed significantly higher (P < .001) secretion of VEGF in clot(+)ASC compared with clot(-)ASC or control(+)ASC. In contrast, clot(-)ASC produced soluble PDGF, and the addition of ASCs results in decreased soluble PDGF with concomitant increases in PDGF immunoreactivity of ASCs. Soluble bFGF levels were low in clot(-)ASC, and were found to increase at early time points in clot(+)ASC. Furthermore, bFGF immunoreactivity could be detected in clot(+)ASC, whereas no bFGF immunoreactivity is present in clot(-)ASC or control(+)ASC. Control(+)ASC displayed a spike in bFGF secretion at day 0, which may be due to a stress response elicited by the encapsulation process. Approximately 98% of available platelets in whole blood were concentrated in the clot on formation.

CONCLUSIONS

Fibrin clots made by this method retain high concentrations of platelets, and when incorporated with ASCs show modulated secretion and immunoreactivity of VEGF, PDGF, and bFGF.

CLINICAL RELEVANCE

Whole blood fibrin clots capture platelets and release growth factors, and the addition of ASCs increases VEGF release for up to 2 weeks after clot formation. This suggests that whole blood fibrin clots may be a viable scaffold and delivery vehicle for future stem cell treatments.

Circumferential Suture Repair of Isolated Horizontal Meniscal Tears Augmented With Fibrin Clot

Traditionally, horizontal cleavage meniscus tears have been associated with osteoarthritis, indicative of the degenerative process. Recent treatment measures have focused on maintaining as much meniscal tissue as possible, despite the routine extension of these tears into the central white-white zones. In the absence of tunnel drilling for cruciate ligament reconstructions, the use of an exogenous fibrin clot is a useful adjunct to increase the local growth factors at the tear repair to aid in healing. This surgical technique is to describe the use of an all-arthroscopic tied circumferential suture repair of horizontal meniscal tears augmented with exogenous fibrin clot to treat all locations of horizontal meniscal tears.

Platelet-Rich Fibrin Facilitates Rabbit Meniscal Repair by Promoting Meniscocytes Proliferation, Migration, and Extracellular Matrix Synthesis

Although platelet-rich fibrin (PRF) has been used in clinical practice for some time, to date, few studies reveal its role as a bioactive scaffold in facilitating meniscal repair. Here, the positive anabolic effects of PRF on meniscocytes harvested from the primary culture of a rabbit meniscus were revealed. The rabbit meniscocytes were cultured with different concentrations of PRF-conditioned medium, and were evaluated for their ability to stimulate cell migration, proliferation, and extracellular matrix formation. In vivo, meniscal defects were created via an established rabbit animal model and were evaluated by a histology-based four-stage scoring system to validate the treatment outcome three months postoperatively. The in vitro results showed that PRF could induce cellular migration and promote proliferation and meniscocyte extracellular matrix (ECM) synthesis of cultured meniscocytes. In addition, PRF increased the formation and deposition of cartilaginous matrix produced by cultured meniscocytes. Morphological and histological evaluations demonstrated that PRF could facilitate rabbit meniscal repair. The data highlight the potential utility of using PRF in augmenting the healing of meniscal injuries. These advantages would benefit clinical translation, and are a potential new treatment strategy for meniscal repair.

Tibiofemoral Contact Mechanics with Horizontal Cleavage Tear and Resection of the Medial Meniscus in the Human Knee

BACKGROUND

The meniscus is known to increase the contact area and decrease contact pressure in the tibiofemoral compartments of the knee. Radial tears of the meniscal root attachment along with partial resections of the torn meniscal tissue decrease the contact area and increase pressure; however, there is a lack of information on the effects of a horizontal cleavage tear (HCT) and partial leaf meniscectomy of such tears on tibiofemoral contact pressure and contact area.

METHODS

Twelve fresh-frozen human cadaveric knees were tested under 10 conditions: 5 serial conditions of posterior medial meniscectomy (intact meniscus, HCT, repaired HCT, inferior leaf resection, and resection of both inferior and superior leaves), each at 2 knee flexion angles (0° and 60°) under an 800-N axial load. Tekscan sensors (model 4000) were used to measure the contact pressure and contact area.

RESULTS

HCT and HCT repair resulted in small changes in the contact area and an increase in contact pressure compared with the intact condition. Resection of the inferior leaf resulted in significantly decreased contact area (to a mean 82.3% of the intact condition at 0° of flexion and 81.8% at 60° of flexion; p < 0.05) and increased peak contact pressure (a mean 36.3% increase at 0° flexion and 43.2% increase at 60° flexion; p < 0.05) in the medial compartment. Further resection of the remaining superior leaf resulted in additional significant decreases in contact area (to a mean 60.1% of the intact condition at 0° of flexion and 49.7% at 60° of flexion; p < 0.05) and increases in peak contact pressure (a mean 79.2% increase at 0° of flexion and 74.9% increase at 60° of flexion; p < 0.05).

CONCLUSIONS

Resection of meniscal tissue forming the inferior leaf of an HCT resulted in substantially decreased contact area and increased contact pressure. Additional resection of the superior leaf resulted in a further significant decrease in contact area and increase in contact pressure in the medial compartment.

CLINICAL RELEVANCE

Repair or minimal resection of meniscal tissue of an HCT may be preferred to complete leaf resection to maintain knee tibiofemoral contact mechanics.

Tissue adhesives for meniscus tear repair: an overview of current advances and prospects for future clinical solutions

Menisci are crucial structures in the knee joint as they play important functions in load transfer, maintaining joint stability and in homeostasis of articular cartilage. Unfortunately, ones of the most frequently occurring knee injuries are meniscal tears. Particularly tears in the avascular zone of the meniscus usually do not heal spontaneously and lead to pain, swelling and locking of the knee joint. Eventually, after a (partial) meniscectomy, they will lead to osteoarthritis. Current treatment modalities to repair tears and by that restore the integrity of the native meniscus still carry their drawbacks and a new robust solution is desired. A strong tissue adhesive could provide such a solution and could potentially improve on sutures, which are the current gold standard. Moreover, a glue could serve as a carrier for biological compounds known to enhance tissue healing. Only few tissue adhesives, e.g., Dermabond(®) and fibrin glue, are already successfully used in clinical practice for other applications, but are not considered suitable for gluing meniscus tissue due to their sub-optimal mechanical properties or toxicity. There is a growing interest and research field focusing on the development of novel polymer-based tissue adhesives, but up to now, there is no material specially designed for the repair of meniscal tears. In this review, we discuss the current clinical gold standard treatment of meniscal tears and present an overview of new developments in this field. Moreover, we discuss the properties of different tissue adhesives for their potential use in meniscal tear repair. Finally, we formulate recommendations regarding the design criteria of material properties and adhesive strength for clinically applicable glues for meniscal tears.