Trephination of incomplete meniscal tears

Current Practices for Rehabilitation After Meniscus Repair: A Survey of Members of the American Orthopaedic Society for Sports Medicine

Background

There is no consensus among sports medicine surgeons in North America on postoperative rehabilitation strategy after meniscus repair. Various meniscal tear types may necessitate a unique range of motion (ROM) and weightbearing rehabilitation protocol.

Purpose

To assess the current landscape of how sports medicine practitioners in the American Orthopedic Society for Sports Medicine (AOSSM) rehabilitate patients after the repair of varying meniscal tears.

Study Design

Cross-sectional study.

Methods

A survey was distributed to 2973 AOSSM members by email. Participants reviewed arthroscopic images and brief patient history from 6 deidentified cases of meniscus repair-in cases 1 to 3, the tears retained hoop integrity (more stable repair), and in cases 4 to 6, the tear patterns represented a loss of hoop integrity. Cases were shuffled before the presentation. For each case, providers were asked at what postoperative time point they would permit (1) partial weightbearing (PWB), (2) full weightbearing (FWB), (3) full ROM, and (4) ROM allowed immediately after surgery.

Results

In total, 451 surveys were completed (15.2% response). The times to PWB and FWB in cases 1 to 3 (median, 0 and 4 weeks, respectively) were significantly lower than those in cases 4 to 6 (median, 4 and 6 weeks, respectively) (P < .001). In tears with retained hoop integrity, the median time to PWB was immediately after surgery, whereas in tears without hoop integrity, the median time to PWB was at 4 weeks postoperatively. Similarly, the median time to FWB in each tear with retained hoop integrity was 4 weeks after surgery, while it was 6 weeks in each tear without hoop integrity. However, regardless of tear type, most providers (67.1%) allowed 0° to 90° of ROM immediately after surgery and allowed full ROM at 6 weeks. Most providers (83.3%) braced the knee after repair regardless of hoop integrity and utilized synovial rasping/trephination with notch microfracture-a much lower proportion of providers utilized biologic augmentation (9%).

Conclusion

Sports medicine practitioners in the AOSSM rehabilitated meniscal tears differently based on hoop integrity, with loss of hoop stresses triggering a more conservative approach. A majority braced and utilized in situ adjuncts for biological healing, while a minority added extrinsic biologics.

Arthroscopic meniscus repair and augmentation with autologous fibrin clot in Indian population: A 2-year prospective study

INTRODUCTION

This study was proposed to evaluate the efficacy of fibrin clot augmentation in meniscal tear using inside-out meniscal repair.

METHODS

A total of 35 patients with meniscus tears were operated on with inside-out meniscus repair and fibrin clot augmentation. Patients were evaluated preoperatively and postoperatively with clinical criteria, Lysholm knee scoring system, and MRI.

RESULTS

Out of the total 35 cases, 5 cases were lost to follow-up. Clinical improvement was observed in 29 out of 30 patients (96.6%). The mean Lysholm score improved significantly from 67.63 ± 6.55 points preoperatively to 92.0 ± 2.9 points postoperatively (P < 0.05) in 3 years follow-up. Follow-up MRI in all patients revealed complete healing except in 1 case where the patient presented with recurrence of symptoms such as pain and locking which resolved with partial meniscectomy. Paraesthesia in the anterior part of the knee was observed in 2 cases. (6.6%).

CONCLUSION

We conclude that fibrin clot augmentation is a good cost-effective modality of treatment for repairable meniscus tears to preserve the meniscus and decrease the point contact pressure on the condyles which may prevent the early occurrence of osteoarthritis.

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.

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.

Mesenchymal stem cells for enhancing biological healing after meniscal injuries

The meniscus is a semilunar fibrocartilage structure that plays important roles in maintaining normal knee biomechanics and function. The roles of the meniscus, including load distribution, force transmission, shock absorption, joint stability, lubrication, and proprioception, have been well established. Injury to the meniscus can disrupt overall joint stability and cause various symptoms including pain, swelling, giving-way, and locking. Unless treated properly, it can lead to early degeneration of the knee joint. Because meniscal injuries remain a significant challenge due to its low intrinsic healing potential, most notably in avascular and aneural inner two-thirds of the area, more efficient repair methods are needed. Mesenchymal stem cells (MSCs) have been investigated for their therapeutic potential in vitro and in vivo. Thus far, the application of MSCs, including bone marrow-derived, synovium-derived, and adipose-derived MSCs, has shown promising results in preclinical studies in different animal models. These preclinical studies could be categorized into intra-articular injection and tissue-engineered construct application according to delivery method. Despite promising results in preclinical studies, there is still a lack of clinical evidence. This review describes the basic knowledge, current treatment, and recent studies regarding the application of MSCs in treating meniscal injuries. Future directions for MSC-based approaches to enhance meniscal healing are suggested.

Meniscus Repair Techniques

The menisci play a vital role in maintaining knee function and protecting the chondral surfaces. Acute and chronic tears are common injuries among both young athletes and older patients with early degenerative changes. The progression of physiological derangement and chondral injury after meniscus injury and meniscectomy have prompted interest in expanding meniscus repair techniques. Recent literature encourages an attempt at repair in tear patterns previously declared irreparable if the tissue quality allows. The orthopedic surgeon should understand the multitude of techniques available to them and be prepared to combine techniques to optimize the quality of their repair construct. While biological augmentation may show some promising early results, the quality of the current data precludes strong recommendations in their favor.

Influence of peracetic acid-ethanol sterilisation on the biomechanical properties of human meniscus transplants

Purpose

Meniscus allograft transplantation (MAT) is a possible treatment for patients suffering with pain after meniscectomy. Here, peracetic acid (PAA) sterilised meniscus transplants were investigated on whether they would provide an adequate alternative to fresh-frozen transplants in their viscoelastic and mechanical properties.

Methods

In this analysis, 31 menisci donors (26 male and 5 female) were included. The average donor age was 49.87 years, ranging from 32 to 65 years. Menisci of matched pairs of knees underwent chemical sterilisation while counterparts were left fresh-frozen. Stiffness and load to failure were determined via suture retention. Further menisci were analysed while attached to the tibial bone block using a novel test device to mimic physiological load distribution. Meniscus relaxation, stiffness and failure loads were determined. Histology and biphasic properties of the menisci were examined and results were analysed using paired t-tests.

Results

A novel custom built test device allowed the application of physiological loads for suture retention testing and revealed no significant differences between PAA sterilised (14.85 ± 4.46 N/mm, 50.49 ± 17.01 N) and fresh-frozen (18.26 ± 4.46 N/mm, 59.49 ± 21.07 N) regarding stiffness and failure load, respectively. Furthermore, initial 200 N loading showed significantly higher strain in sterilised menisci (18.87 ± 1.56) compared to fresh frozen (13.81 ± 1.04). Load relaxation experiments demonstrated significantly lower relaxation for sterilised menisci (77.71 ± 1.62) compared to fresh-frozen (89.11 ± 1.00, p-value < 0.0001).

Conclusion

Peracetic acid sterilised human menisci performed equally to fresh-frozen counterparts in a suture retention test and in physiological failure testing providing an adequate alternative. However, meniscus relaxation, biphasic properties and strain were shown to be significantly different between the groups. A common problem of MAT is graft extrusion or shrinkage, therefore the parameters measured here should be considered and may influence meniscus extrusion after transplantation.

Level of evidence

n/a (experimental study)

Meniscal Repair Techniques for Middle- and Posterior-Third Tears

Technical advancements in meniscal repairs have greatly contributed to the ability to repair a variety of meniscal tears that were once thought untreatable. The gold-standard treatment for arthroscopic meniscal body repair remains an inside-out technique. The advantages of this technique are innate to the low-profile nature of the suture-passing construct, which allows for perpendicular access to tears with the benefit of multiple fixation points, in contrast to often bulkier all-inside repair devices. This technique requires a posteromedial or posterolateral incision for safe suture passing and needle retrieval and necessitates a surgical team experienced in this method of repair. However, the newest generation of all-inside devices has allowed for more facile placement of a variety of suture types. The all-inside repair technique includes both capsular-based and meniscal-based fixation, is not limited by a need for additional experienced surgical personnel to pass and retrieve needles, and does not require additional incisions. Regardless of fixation type, meniscal repair has been shown to improve long-term functional scores when compared with meniscectomy. Additionally, biological adjuncts have been introduced into the repair algorithm to improve healing rates when performing isolated meniscal repairs. Preparing the healing site with abrasion or trephination creates vascular channels that can facilitate repair. Intercondylar-notch marrow venting attempts to replicate the environment created by anterior cruciate ligament drilling for which healing rates are notably higher than those with isolated meniscal repairs. The use of fibrin clots in inside-out meniscal repairs with suturing of the clot to the area of the tear has also shown promising early healing rates on both magnetic resonance imaging and second-look arthroscopy. Finally, biological adjuncts such as platelet-rich plasma and concentrated bone marrow aspirate have shown both early clinical and radiographic improvements in Level IV case series, but further research is needed to more definitively measure their utility in the setting of meniscal repair.

Changes in Matrix Components in the Developing Human Meniscus

BACKGROUND

Treatment of meniscal tears is necessary to maintain the long-term health of the knee joint. Morphological elements, particularly vascularity, that play an important role in meniscal healing are known to change during skeletal development.

PURPOSE

To quantitatively evaluate meniscal vascularity, cellularity, collagen, and proteoglycan content by age and location during skeletal development.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Medial and lateral menisci from 14 male and 7 female cadavers aged 1 month to 11 years were collected and evaluated. For each meniscus, histologic and immunohistologic techniques were used to establish the ratio of the area of proteoglycan (safranin O) positivity to the total area (proteoglycan ratio), collagen type I and type II immunostaining positivity, number of blood vessels, and cell density. These features were evaluated over the entire meniscus and also separately in 5 circumferential segments: anterior root, anterior horn, body, posterior horn, and posterior root. Additionally, cell density and number of blood vessels were examined in 3 radial regions: inner, middle, and periphery.

RESULTS

Age was associated with a decrease in meniscal vessel count and cell density, while the proteoglycan ratio increased with skeletal maturity. Differences in vessel counts, cellular density, and proteoglycan ratio in different anatomic segments as well as in the inner, middle, and peripheral regions of the developing menisci were also observed. Collagen immunostaining results were inconsistent and not analyzed.

CONCLUSION

The cellularity and vascularity of the developing meniscus decrease with age and the proteoglycan content increases with age. All of these parameters are influenced by location within the meniscus.

CLINICAL RELEVANCE

Age and location differences in meniscal morphology, particularly in the number of blood vessels, are expected to influence meniscal healing.

Updates and Advances in the Management of Lateral Meniscal Radial Tears: A Critical Analysis Review

Because of their increased mobility, lack of resistance to hoop stresses, and decreased blood supply, radial tears of the lateral meniscus are more troublesome to heal than vertical longitudinal tears. Given the success of meniscal root repairs, radial tears of the lateral meniscal body should be given strong consideration for repair because of a more reproducible ability to heal such lesions in young, active patients. Technique options that should be considered for the less common anterior radial tears of the lateral meniscus include outside-in repair, self-capturing suture-passing devices, and orthobiologic treatments to stimulate healing. Although a variety of suture techniques, including the double horizontal mattress and horizontal butterfly patterns, have demonstrated improvements in patient outcomes, evidence is still limited with regard to the ideal suture pattern for radial tears.

Editorial Commentary: Platelet-Rich Plasma and Knee Meniscal Repair-The Use of Biologics Has Not Progressed Substantially Since 1983

When it comes to meniscal repair, optimizing the local biological environment at the repair site by performing trephination to create bleeding from the extracapsular capillary network, by rasping to abrade the local synovial tissue, or by creating bleeding from the intercondylar notch is recommended. The addition of platelet-rich plasma probably also helps, especially absent the bleeding when meniscal repair is performed concomitantly with anterior cruciate ligament reconstruction. However, pending future research, there is not enough data to recommend platelet-rich plasma augmentation for meniscal repair in all cases.

Management of traumatic meniscus tears: the 2019 ESSKA meniscus consensus

PURPOSE

The importance of meniscus integrity in the prevention of early osteoarthritis is well known, and preservation is accepted as the primary goal. The purpose of the ESSKA (European Society for Sports Traumatology, Knee Surgery and Arthroscopy) European consensus on traumatic meniscus tears was to provide recommendations for the treatment of meniscus tears based on both scientific evidence and the clinical experience of knee experts.

METHODS

Three groups of surgeons and scientists elaborated and ratified the so-called formal consensus process to define the recommendations for the management of traumatic meniscus tears. A traumatic meniscus tear was defined as a tear with an acute onset of symptoms caused by a sufficient trauma. The expert groups included a steering group of eight European surgeons and scientists, a rating group of another nineteen European surgeons, and a peer review group. The steering group prepared twenty-seven question and answer sets based on the scientific literature. The quality of the answers received grades of A (a high level of scientific support), B (scientific presumption), C (a low level of scientific support) or D (expert opinion). These question and answer sets were then submitted to and evaluated by the rating group. All answers were scored from 1 (= totally inappropriate) to 9 (= totally appropriate) points. Thereafter, the comments of the members of the rating group were incorporated by the steering group and the consensus was submitted to the rating group a second time. Once a general consensus was reached between the steering and rating groups, the finalized question and answer sets were submitted for final review by the peer review group composed of representatives of the ESSKA-affiliated national societies. Eighteen representatives replied.

RESULTS

The review of the literature revealed a rather low scientific quality of studies examining the treatment of traumatic meniscus tears. Of the 27 questions, only one question received a grade of A (a high level of scientific support), and another received a grade of B (scientific presumption). The remaining questions received grades of C and D. The mean rating of all questions by the rating group was 8.2 (95% confidence interval 8.1-8.4). A general agreement that MRI should be performed on a systematic basis was not achieved. However, MRI was recommended when arthroscopy would be considered to identify concomitant pathologies. In this case, the indication for MRI should be determined by a musculoskeletal specialist. Based on our data, stable left in situ lateral meniscus tears appear to show a better prognosis than medial tears. When repair is required, surgery should be performed as early as possible. Evidence that biological enhancement such as needling or the application of platelet-rich plasma would improve healing was not identified. Preservation of the meniscus should be considered as the first line of treatment because of an inferior clinical and radiological long-term outcome after partial meniscectomy compared to meniscus repair.

DISCUSSION

The consensus was generated to present the best possible recommendations for the treatment of traumatic meniscus tears and provides some groundwork for a clinical decision-making process regarding the treatment of meniscus tears. Preservation of the meniscus should be the first line of treatment when possible, because the clinical and radiological long-term outcomes are worse after partial meniscectomy than after meniscus preservation. The consensus clearly states that numerous meniscus tears that were considered irreparable should be repaired, e.g., older tears, tears in obese patients, long tears, etc. LEVEL OF EVIDENCE: II.

Short-Term Outcomes of Percutaneous Trephination with a Platelet Rich Plasma Intrameniscal Injection for the Repair of Degenerative Meniscal Lesions. A Prospective, Randomized, Double-Blind, Parallel-Group, Placebo-Controlled Study

Meniscal tears are the most common orthopaedic injuries, with chronic lesions comprising up to 56% of cases. In these situations, no benefit with surgical treatment is observed. Thus, the purpose of this study was to investigate the effectiveness and safety of percutaneous intrameniscal platelet rich plasma (PRP) application to complement repair of a chronic meniscal lesion. This single centre, prospective, randomized, double-blind, placebo-controlled study included 72 patients. All subjects underwent meniscal trephination with or without concomitant PRP injection. Meniscal non-union observed in magnetic resonance arthrography or arthroscopy were considered as failures. Patient related outcome measures (PROMs) were assessed. The failure rate was significantly higher in the control group than in the PRP augmented group (70% vs. 48%, P = 0.04). Kaplan-Meyer analysis for arthroscopy-free survival showed significant reduction in the number of performed arthroscopies in the PRP augmented group. A notably higher percentage of patients treated with PRP achieved minimal clinically significant difference in visual analogue scale (VAS) and Knee injury and Osteoarthritis Outcome Score (KOOS) symptom scores. Our trial indicates that percutaneous meniscal trephination augmented with PRP results in a significant improvement in the rate of chronic meniscal tear healing and this procedure decreases the necessity for arthroscopy in the future (8% vs. 28%, P = 0.032).

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.

Magnetic Resonance Imaging and Functional Outcomes After a Polyurethane Meniscal Scaffold Implantation: Minimum 5-Year Follow-up

PURPOSE

To report the magnetic resonance imaging (MRI) and clinical outcomes at a minimum 5-year follow-up in a series of patients with postmeniscectomy syndrome and treated with a polyurethane scaffold.

METHODS

All consecutive patients operated on from September 2008 to February 2011 for either persistent medial or lateral joint line compartmental pain receiving a polyurethane scaffold due to a previous partial meniscus resection with a minimum 5-year follow-up were included. Functional scores (Knee Injury and Osteoarthritis Outcomes Score, International Knee Documentation Committee, Lysholm, and Tegner) were assessed preoperatively and at the last follow-up. The state of the scaffold as well as postoperative scaffold extrusion and the total remaining meniscal volume was also evaluated in MRI.

RESULTS

Thirty-two patients were included. The mean follow-up was 70.8 ± 7.5 months. The functionality of the knees improved in all the scores used (P < .001) except for the Tegner score that stayed steady. Most of meniscal implants showed extrusion of 2.4 mm (95% confidence interval [CI], 1.1-3.7) were smaller and a hyperintensity signal was seen in the MRI. Three scaffolds were resorbed at the last follow-up. The meniscal volume, determined by MRI, was 1.14 cm³ (95% CI, 0.96-1.31) preoperatively and 1.61 cm³ (95% CI, 1.43-1.7) at the last follow-up. No differences were presented.

CONCLUSIONS

The use of a polyurethane meniscal scaffold in patients with a symptomatic meniscus deficit had a good functional outcome at 5 years after surgery. However, the implanted scaffolds did not present normal meniscal tissue with MRI, and the implant volume was considerably less than expected. The fact that most of patients included received different concomitant procedures during scaffold implantation introduces a degree of performance bias into the results.

LEVEL OF EVIDENCE

Level IV, case series.

Angiogenic approaches to meniscal healing

Meniscal injuries commonly result in osteoarthritis causing long term morbidity, lifelong treatment, joint replacement and significant financial burden to the Canadian healthcare system. Injuries to the outer third of the meniscus often heal well due to adequate blood supply. Healing of injuries in the inner two thirds of the meniscus are often critically retarded due to a lack of blood flow necessitating partial meniscectomy in many instances. Localized angiogenesis in the inner meniscus has yet to be achieved despite a belief that vascularization of these lesions corresponds with meniscal healing. This review briefly summarizes the growth factors that have been assessed for a role in meniscal healing and points to a significant knowledge gap in our understanding of meniscal healing.

Development of a Micronized Meniscus Extracellular Matrix Scaffold for Potential Augmentation of Meniscal Repair and Regeneration

Decellularized scaffolds composed of extracellular matrix (ECM) hold promise for repair and regeneration of the meniscus, given the potential for ECM-based biomaterials to aid in stem cell recruitment, infiltration, and differentiation. The objectives of this study were to decellularize canine menisci to fabricate a micronized, ECM-derived scaffold and to determine the cytocompatibility and repair potential of the scaffold ex vivo. Menisci were decellularized with a combination of physical agitation and chemical treatments. For scaffold fabrication, decellularized menisci were cryoground into a powder and the size and morphology of the ECM particles were evaluated using scanning electron microscopy. Histologic and biochemical analyses of the scaffold confirmed effective decellularization with loss of proteoglycan from the tissue but no significant reduction in collagen content. When washed effectively, the decellularized scaffold was cytocompatible to meniscal fibrochondrocytes, synoviocytes, and whole meniscal tissue based on the resazurin reduction assay and histologic evaluation. In an ex vivo model for meniscal repair, radial tears were augmented with the scaffold delivered with platelet-rich plasma as a carrier, and compared to nonaugmented (standard-of-care) suture techniques. Histologically, there was no evidence of cellular migration or proliferation noted in any of the untreated or standard-of-care treatment groups after 40 days of culture. Conversely, cellular infiltration and proliferation were noted in scaffold-augmented repairs. These data suggest the potential for the scaffold to promote cellular survival, migration, and proliferation ex vivo. Further investigations are necessary to examine the potential for the scaffold to induce cellular differentiation and functional meniscal fibrochondrogenesis.

Meniscal Preservation is Important for the Knee Joint

Native joint preservation has gained importance in recent years. This is mostly to find solutions for limitations of arthroplasty. In the knee joint, the menisci perform critical functions, adding stability during range of motion and efficiently transferring load across the tibiofemoral articulation while protecting the cartilage. The menisci are the most common injury seen by orthopedicians, especially in the younger active patients. Advances in technology and our knowledge on functioning of the knee joint have made meniscus repair an important mode of treatment. This review summarizes the various techniques of meniscus tear repair and also describes biological enhancements of healing.

The effect of tissue surface modification with collagenase and addition of TGF-β3 on the healing potential of meniscal tears repaired with tissue glues in vitro

The aim of the current in vitro study was to investigate if tissue surface modification with collagenase and addition of the TGF-β3 can increase the number of cells present in meniscus tears repaired with the use of newly developed tissue adhesives based on isocyanate-terminated block copolymers. Cylindrical explants were harvested from the inner part of bovine menisci. To simulate a full-thickness tear, the central core of the explants was removed and glued back into the defect, with or without incubation in collagenase solution prior to gluing. The repair constructs were then cultured with or without addition of TGF-β3, and assessed for their histological appearance. The histological staining of the constructs confirmed that both developed adhesives were not cytotoxic. After 28 days, meniscus cells were present in direct contact with the glues. The addition of TGF-β3 to the culture medium resulted in the presence of cells that formed a sheath inside the simulated tear and in increased cell numbers at the edges of annulus of the explants. In the group in which the tissue was incubated in collagenase and cultured in medium containing TGF-β3, thicker layers of cells were observed. These results suggest that repairing the torn meniscus with tissue adhesives after pre-treatment of the tissue with collagenase and stimulation with TGF-β3 is a very promising treatment method, especially when treating the inner avascular part of the meniscus. Nevertheless, longer-term in vitro and in vivo studies are needed to confirm the beneficial effects of this combination therapy.

Effect of Microfracture on Meniscal Tear Healing in a Goat (Capra hircus) Model

Meniscal injuries are an extremely common cause of knee pain. Meniscal repairs performed with concomitant anterior cruciate ligament reconstruction appear to heal at a higher rate than meniscal repairs performed in isolation. This may be due in part to the release of marrow elements into the knee and the time of meniscal repair. In cases of isolated meniscal repair, some orthopedic surgeons use microfracture to release marrow elements into the joint as an adjunct to enhance meniscal healing. This study evaluated rates of meniscal tear healing with or without the performance of microfracture in a goat (Capra hircus) model. Forty castrated young adult male goats underwent either a horizontal or a longitudinal 1.0-cm meniscal tear with or without microfracture. All procedures were performed open, in a bloodless field. Meniscal tears were created in the peripheral half of the body of the medial meniscus. The goats were euthanized at 6 months, and meniscal tears were analyzed and classified as complete healing, partial healing, or no healing by direct visualization. A probe was used as an aid to evaluate and classify the meniscal tears. Twenty (87%) of 23 goat meniscal tears showed at least partial healing when performed with concomitant microfracture. Only 5 (29%) of 17 menisci showed any healing in goats that did not receive microfracture. This difference in healing rates was statistically significant (P<.001). Fifteen (65%) meniscal tears accomplished with microfracture were completely healed, whereas only 2 (12%) menisci showed complete healing without microfracture (P<.001). The results of this study suggest that the release of bone marrow elements into the knee by microfracture improves meniscal healing rates.

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.

Evaluation of Peripheral Vertical Nondegenerative Medial Meniscus Tears Treated With Trephination Alone at the Time of Anterior Cruciate Ligament Reconstruction

PURPOSE

To determine (1) subjective results and incidence of symptomatic medial meniscus tears (MMTs) in patients treated with trephination alone compared with a control group without meniscus tears and (2) if trephination treatment resulted in a higher incidence of knee arthritis compared with controls with intact menisci.

METHODS

Between 1997 and 2010, 419 patients met the inclusion criteria of having an isolated anterior cruciate ligament (ACL) tear, peripheral vertical nondegenerative MMT treated with trephination alone, no lateral meniscus tears, normal radiographs before surgery, and no bilateral knee involvement. A control group of 462 patients included patients who met the same criteria but without MMT. Objective data included International Knee Documentation Committee (IKDC) objective evaluation. Subjective data included IKDC and Cincinnati Knee Rating System (CKRS) scores.

RESULTS

Objective follow-up was obtained for 191 patients in the study group and 200 patients in the control group (mean, 5.6 and 5.9 years, respectively; range, 2 to 16 years). Subjective survey follow-up was obtained for 312 patients in the study group and 343 patients in the control group (mean, 7.0 and 7.1 years, respectively). The mean CKRS score was 91.8 ± 13.3 for the study group and 92.3 ± 10.9 for the control group (P = .27). The mean IKDC score was 86.5 ± 15.8 for the study group and 86.7 ± 16.3 for the control group (P = .81). Subsequent MMTs occurred in 51 patients (16.3%) in the study group and 20 patients (5.8%) in the control group (P < .0001). IKDC radiographic ratings were normal for 95% of the study group and 92% of the control group (P = .18).

CONCLUSIONS

Patients with peripheral nondegenerative MMTs treated with trephination alone had a 16.3% rate of subsequent symptomatic MMTs compared with 6% in patients with intact menisci. However, no statistically significant differences were found between groups for radiographic and subjective results.

LEVEL OF EVIDENCE

Level III, therapeutic case control study.

Current strategies in meniscal regeneration

The meniscus plays an important role in the biomechanics and tribology of the knee joint. Damage to or disease of the meniscus is now recognized to predispose to the development of osteoarthritis. Treatment of meniscal injury through arthroscopic surgery has become one of the most common orthopedic surgical procedures, and in the United States this can represent 10 to 20% of procedures related to the knee. The meniscus has a limited healing capacity constrained to the vascularized periphery and therefore, surgical repair of the avascular regions is not always feasible. Replacement and repair of the meniscus to treat injuries is being investigated using tissue engineering strategies. Promising as these approaches may be, there are, however, major barriers to overcome before translation to the clinic.

Augmentation techniques for isolated meniscal tears

Meniscal tears are relatively common injuries sustained by athletes and non-athletes alike and have far reaching functional and financial implications. Studies have clearly demonstrated the important biomechanical role played by the meniscus. Long-term follow-up studies of post-menisectomy patients show a predisposition toward the development of degenerative arthritic changes. As such, substantial efforts have been made by researchers and clinicians to understand the cellular and molecular basis of meniscal healing. Proinflammatory cytokines have been shown to have a catabolic effect on meniscal healing. In vitro and some limited in vivo studies have shown a proliferative and anabolic response to various growth factors. Surgical techniques that have been developed to stimulate a healing response include mechanical abrasion, fibrin clot application, growth factor application, and attempts at meniscal neovascularization. This article discusses various augmentation techniques for meniscal repair and reviews the current literature with regard to fibrin clot, platelet rich plasma, proinflammatory cytokines, and application of growth factors.

Meniscus tears that can be left in situ, with or without trephination or synovial abrasion to stimulate healing

To determine which meniscus tears to leave in situ, the clinician must know whether the meniscus tear is degenerative or nondegenerative, stable or unstable, in an anterior cruciate ligament (ACL)-stable or ACL-unstable knee, and whether it is in the medial or lateral compartment. Symptomatic medial meniscus tears in ACL-intact knees are almost always degenerative in nature and should be removed. Generally, the only type of medial meniscus that can be left in situ is a peripheral, vertical, nondegenerative tear, but these tears are not displaceable, are asymptomatic, and are usually seen in a patient with an ACL tear. In the lateral compartment, most tears can be left in situ and the only tears that need to be repaired are displaceable tears that extend anterior to the popliteus tendon. Although many meniscus repair techniques and fixation devices are available, all factors related to healing and stability should be considered to determine treatment.

Biological enhancement of meniscus repair and replacement

When a meniscus injury occurs, it is generally accepted that preserving the meniscus is important for life-long joint preservation. Traditional suture repair of the meniscus has good results; however, the healing potential of meniscus tissue remains as a biological challenge because it is not a completely vascularized structure. For this reason, investigators have continued to search for adjuncts to improve clinical results. Mechanical adjuncts, local factor enhancement, scaffolds, gene therapy, and cell therapy have all been examined as options for improvement of biology and structure. This study reviews the basic science and clinical application of these modalities and provides an assessment of techniques on the horizon.

Meniscal repair

The meniscus plays an important role in preventing osteoarthritis of the knee. Repair of a meniscal lesion should be strongly considered if the tear is peripheral and longitudinal, with concurrent anterior cruciate ligament reconstruction, and in younger patients. The probability of healing is decreased in complex or degenerative tears, central tears, and tears in unstable knees. Age or extension of the tear into the avascular area are not exclusion criteria. Numerous repair techniques are available, and suture repair seems to provide superior biomechanical stability. However, the clinical success rate does not correlate well with the mechanical strength of the repair technique. Biologic factors might be of greater importance to the success of meniscal repair than the surgical technique. Therefore, the decision on the most appropriate repair technique should not rely on biomechanical parameters alone. Contemporary all-inside repair systems have decreased the operating time and the level of surgical skill required. Despite the ease of use, there is a potential for complications because of the close proximity of vessels, nerves, and tendons, of which the surgeon should be aware. There is no clear consensus on postoperative rehabilitation. Weight bearing in extension would most likely not be crucial in typical longitudinal lesions. However, higher degrees of flexion, particularly with weight bearing, give rise to large excursions of the menisci and to shear motions, and should therefore be advised carefully. Long-term studies show a decline in success rates with time. Further studies are needed to clarify the factors relevant to the healing of the menisci. Tissue engineering techniques to enhance the healing in situ are promising but have not yet evolved to a practicable level.

All-inside meniscal repair

All-inside meniscal repair has gained widespread popularity over recent years. The devices and techniques have rapidly evolved, resulting in increased ease of use and reduced surgical times and risk to the neurovascular structures. Despite these advances, inside-out suture repairs remain the current gold standard, with proven long-term results. All-inside techniques must continue to be compared to inside-out meniscal repair.

Repeat revision of anterior cruciate ligament reconstruction: a retrospective review of management and outcome of 10 patients with an average 3-year follow-up

BACKGROUND

To the authors' knowledge, no previous published study has focused on management and outcome of repeat revision of anterior cruciate ligament reconstruction in terms of functional result and meniscus and articular cartilage status.

HYPOTHESIS

Repeat revision of anterior cruciate ligament reconstruction improves knee stability, but with inferior results for functional outcome compared with primary anterior cruciate ligament reconstruction. Meniscal tears and subsequent articular cartilage degeneration are more prevalent with successive revisions due to recurrent laxity.

STUDY DESIGN

Case series; Level of evidence, 4.

MATERIALS AND METHODS

Between February 2003 and November 2006, a consecutive series of 10 patients with an average age at 30 years (range, 17-48) were operated on for a repeat revision of anterior cruciate ligament reconstruction (2 revisions after a primary reconstruction) with arthroscopic procedures. A clinical and a radiographic evaluation were performed to assess anterior cruciate ligament reconstruction failures, outcome of revisions, and causes of failures. Meniscal tears and articular cartilage lesions were analyzed.

RESULTS

The average follow-up of the second revision was 38 months (range, 12-61). At latest follow-up, final International Knee Documentation Committee assessment was excellent or good in 7 cases. Postoperatively, only 2 patients recovered to the same sports activity level they had before their first anterior cruciate ligament reconstruction. Four had a lower level, and 4 discontinued sports activity. The postoperative average side-to-side KT-1000 arthrometer maximum manual difference was 1.3 +/- 1.9 mm. Nine patients had meniscal tears and 7 had articular cartilage lesions. Meniscal tears, meniscectomies, and articular cartilage degeneration increased after the second revision (P = .016, P = .0098, and P = .0197, respectively). Severe articular cartilage degeneration (International Cartilage Repair Society grade III and IV lesions) was found in patients with bad functional outcome (final International Knee Documentation Committee assessment C or D) (P = .0472). Incidence of articular cartilage degeneration was found to be more prevalent in cases of meniscal tears and partial meniscectomy at the same tibiofemoral compartment (P = .0157). Index anterior cruciate ligament reconstruction and first revision failures were caused by recurrent trauma (60% and 70%, respectively) or a surgical technical error with tunnel malpositioning (40% and 10%, respectively).

CONCLUSION

Outcome of repeat revision of anterior cruciate ligament reconstruction was excellent or good in 70% of the cases, although decreased after the second revision, in relation to the occurrence of meniscal tears and articular cartilage lesions. Meniscal and articular cartilage lesions were more frequent and more severe with recurrent laxity. The cause of failures was mainly recurrent trauma, followed by surgical technical errors.

Clinical significance of intrasubstance meniscal lesions on MRI

Grade 2 meniscal changes on MRI are linear signals confined within the meniscus thought to represent areas of meniscal degeneration or intrasubstance tears. It has been reported that in only 10% of cases is a meniscal tear detected during subsequent arthroscopy. Usually non-operative management is appropriate, but in some cases, grade 2 meniscal changes are seen on MRI in patients with a typical presentation of a meniscal tear. In this circumstance, an arthroscopic partial meniscectomy may be indicated and an MRI report, which describes the meniscus as being normal, may be confusing. A pilot study of 10 consecutive symptomatic patients (mean age 28.1 years) with a grade 2 meniscal signal on MRI was performed. At arthroscopy, with thorough examination of the meniscus using a probe, an intrasubstance tear was detected in all 10 patients. Partial meniscectomy was performed, with a mean follow-up of 6.7 months. All but one patient (due to other pathology) had marked improvement in pain and function. Thus, the authors believe that grade 2 signal changes should be reported in a manner that raises the possibility that they may cause symptoms and that the presence of any intrasubstance changes should be clearly conveyed in the report.

The extent of laceration of circumferential fibers with suture repair of the knee meniscus. Winner of the AGA DonJoy award 2006

INTRODUCTION

Cannulas used with suture based meniscal repair techniques can potentially injure the load transmitting fibers of the meniscus. The subject of this study was to quantify this effect in a porcine in vitro model.

MATERIALS AND METHODS

From fresh frozen medial porcine menisci tissue specimens were harvested following the course of the peripheral circumferential fibers bundles. In the first part of the study the tissue samples were perforated with the cannulas of either a Fast Fix or a Rapidloc device or with an 18-gauge needle. The specimens were then visually inspected for fiber damage using low power microscopy and the mean size of the laceration was measured. Finally, the extent of the tissue laceration was indirectly determined using non-contact strain measurements of the samples before and after puncture.

RESULTS

When advanced with the cutting edge perpendicular to the fibers, the cannulas consistently cut the fibers while those were rather separated with the opposite orientation. It could be shown that specimens with a mean width of 8.1 mm lost 25% of the load transmitting cross section when being perforated two times with a Fast Fix device (P < 0.001). This effect is negated when the cannula was oriented in line with the fibers.

CONCLUSIONS

Cannulas used for suture based meniscal repair can cause a substantial laceration of the meniscal tissue. The effect strongly depends on the orientation of the cutting edge of the cannula relative to the course of the fibers and can thus potentially be avoided by an appropriate handling and design.

Biomedical devices in meniscal repair

Preservation of the menisci is increasingly emphasized in orthopedic care of the knee. Techniques are rapidly emerging that allow easier accomplishment of this goal. In particular, the development of all-inside arthroscopic meniscal repair devices has facilitated more ready repair. A number of laboratory and clinical studies have examined these devices and comparisons with more traditional techniques have been made. Numerous reports of potential complications from these new technologies have also been described in the literature. This review covers the current options for treatment of meniscal repair, laboratory and clinical data, and also potential complications.

Nonoperative treatment of partial-thickness meniscal tears identified during anterior cruciate ligament reconstruction

The reported incidence and treatment of partial-thickness meniscal tears seen at anterior cruciate ligament (ACL) reconstruction varies widely. The success of nonoperative treatment of partial meniscal tears identified during ACL reconstruction at our institution was reviewed. All incomplete meniscal tears were treated with observation, all full-thickness tears were treated with repair or partial meniscectomy. Partial tears of the lateral meniscus were noted three times more commonly than in the medial meniscus and were seen more acutely after ACL injury than full-thickness tears. At 2-year follow-up, excellent knee function was noted when these tears were treated nonoperatively.

Comparison of partial meniscectomy versus meniscus repair for bucket-handle lateral meniscus tears in anterior cruciate ligament reconstructed knees

PURPOSE

For patients who underwent anterior cruciate ligament (ACL) reconstruction and had an unstable bucket-handle tear and no other meniscus lesions or articular damage, we sought to determine if repair of the lateral meniscus was superior to partial meniscectomy with regard to subjective and objective results.

TYPE OF STUDY

Retrospective cohort study.

METHODS

Between 1982 and 1995, 91 patients met the inclusion criteria of having an ACL tear and an isolated unstable, bucket-handle meniscus tear. Patients were excluded if they had medial meniscus tears or chondral lesions. All patients underwent ACL reconstruction using patellar tendon autografts. Sixty-seven lateral menisci underwent repair using an inside-outside technique, while 24 lateral menisci were partially excised. Subjective follow-up evaluation was obtained with a modified Noyes questionnaire. Patients were objectively evaluated according to International Knee Documentation Committee (IKDC) knee evaluation criteria.

RESULTS

The mean subjective total score for the repair group was 92.5 +/- 9.4 (mean time, 7.0 +/- 2.6 years postoperatively), and the mean score for the removal group was 88.7 +/- 13.2 (mean time 11.1 +/- 4.0 years; P =.2014). The mean pain scores were 16.8 +/- 3.1 points for the repair group and 14.0 +/- 4.0 for the partial excision group, which was statistically significant (P =.0478). The distribution of IKDC overall grades was not statistically significantly different between groups (P =.0947). Two of 67 meniscus repairs failed, requiring subsequent removal.

CONCLUSIONS

Results showed that patients in the partial meniscectomy group had more pain than in the repair group, but no statistically significant difference was found between groups for overall subjective score or IKDC grade. Further follow-up evaluation is needed before definitive treatment can be recommended.

LEVEL OF EVIDENCE

Level III.