Meniscal Healing Research Articles

Advances in the Mechanisms Affecting Meniscal Avascular Zone Repair and Therapies.

Injuries to menisci are the most common disease among knee joint-related morbidities and cover a widespread population ranging from children and the general population to the old and athletes. Repair of the injuries in the meniscal avascular zone remains a significant challenge due to the limited intrinsic healing capacity compared to the peripheral vascularized zone. The current surgical strategies for avascular zone injuries remain insufficient to prevent the development of cartilage degeneration and the ultimate emergence of osteoarthritis (OA). Due to the drawbacks of current surgical methods, the research interest has been transferred toward facilitating meniscal avascular zone repair, where it is expected to maintain meniscal tissue integrity, prevent secondary cartilage degeneration and improve knee joint function, which is consistent with the current prevailing management idea to maintain the integrity of meniscal tissue whenever possible. Biological augmentations have emerged as an alternative to current surgical methods for meniscal avascular zone repair. However, understanding the specific biological mechanisms that affect meniscal avascular zone repair is critical for the development of novel and comprehensive biological augmentations. For this reason, this review firstly summarized the current surgical techniques, including meniscectomies and meniscal substitution. We then discuss the state-of-the-art biological mechanisms, including vascularization, inflammation, extracellular matrix degradation and cellular component that were associated with meniscal avascular zone healing and the advances in therapeutic strategies. Finally, perspectives for the future biological augmentations for meniscal avascular zone injuries will be given.

Second-Look Arthroscopic Evaluation of Healing Rates After Arthroscopic Repair of Meniscal Tears: A Systematic Review and Meta-analysis.

Background:Evaluation of meniscal healing status after repair is important, as it allows the surgeon to inform patients whether they can increase their activities or return to sports.Purpose:To identify the healing rates after arthroscopic repair of meniscal tears via second-look arthroscopic evaluation.Study Design:Systematic review; Level of evidence, 4.Methods:Searches of PubMed, Embase, Scopus, and the Cochrane databases were conducted to identify relevant studies published before June 1, 2020. Studies were eligible for this meta-analysis if they provided data regarding healing status of the meniscus at second-look arthroscopy. Random-effects meta-analyses were generated to provide pooled meniscal healing estimates. We further performed subgroup analysis to investigate the healing rates of the meniscus under different situations.Results:A total of 41 studies with 1908 individuals were included in the study. The pooled analysis showed the complete healing rate was 74% (95% confidence interval [CI], 67%-80%), the partial healing rate was 10% (95% CI, 6%-16%), and the failure rate was 12% (95% CI, 10%-15%) for arthroscopic repair of meniscal tears via second-look arthroscopic evaluation. Sensitivity analysis demonstrated that no individual study affected the overall healing rate by >1%. Subgroup analysis found higher meniscal healing rates in patients with the following characteristics: age <40 years, male, body mass index <26, red-red tear location, tear in posterior horn, vertical tear, outside-in technique, repair concomitant with anterior cruciate ligament reconstruction, weight-restricted rehabilitation, and time interval from meniscal repair to second-look arthroscopy >12 months.Conclusion:In this systematic review, the complete healing rate was 74%, the partial healing rate was 10%, and the failure rate was 12% for arthroscopic repair of meniscal tears via second-look arthroscopic evaluation.

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.

Characterization of Macroporous Polycaprolactone/Silk Fibroin/Gelatin/Ascorbic Acid Composite Scaffolds and In Vivo Results in a Rabbit Model for Meniscus Cartilage Repair.

Meniscus injuries in the inner avascular zone have weak intrinsic self-healing capacity and often progress to osteoarthritis. This study focused on evaluating the effects of polycaprolactone/silk fibroin/gelatin/ascorbic acid (PCL/SF/Gel/AA) composite scaffolds seeded with adipose-derived mesenchymal stem cells (ASCs), in the meniscus repair. To this end, composite scaffolds were cross-linked using N-hydroxysuccinimide and 1-ethyl-3-(3-dimethyl-aminopropyl)-1-carbodiimide hydrochloride. Scaffolds were then characterized by scanning electron microscope, mechanical tests, total antioxidant capacity, swelling, and toxicity tests. The PCL/SF/Gel/AA scaffolds exhibited suitable mechanical properties. Furthermore, vitamin C rendered them the highest antioxidant capacity. The PCL/SF/Gel/AA scaffolds also showed good biocompatibility and proliferation for chondrocytes. Moreover, the PCL/SF/Gel/AA scaffold seeded with allogeneic ASCs was engrafted in New Zealand rabbits who underwent unilateral punch defect in the medial meniscus of the right knee. After 2 months postimplantation, macroscopic and histologic studies for new meniscus cartilage were performed. Our results indicated that the PCL/SF/Gel/AA composite scaffolds seeded with allogeneic ASCs could successfully improve meniscus healing in damaged rabbits.

Association Between Transtibial Meniscus Root Repair and Rate of Meniscal Healing and Extrusion on Postoperative Magnetic Resonance Imaging: A Prospective Multicenter Study.

Background:Prospective studies evaluating second-look imaging of meniscus root repair using a transtibial pull-out technique are limited; therefore, optimal surgical indications and the technique for meniscus root repair remain uncertain.Hypothesis:It was hypothesized that there would be a high rate of healing, improvement in meniscal extrusion, and prevention of articular cartilage degeneration and subchondral bone abnormalities after meniscus root repair.Study Design:Case series; Level of evidence, 4.Methods:Consecutive patients undergoing transtibial root repair were prospectively enrolled at 2 orthopaedic centers between March 2017 and January 2019. Pre- and postoperative magnetic resonance imaging (MRI) scans were reviewed by a musculoskeletal radiologist in a blinded fashion for meniscal healing, quantification of extrusion, articular cartilage grade, subchondral bone changes, and coronary/meniscotibial ligament abnormalities. Given persistent extrusion observed on postoperative MRI scans, an additional 10 patients gave consent and were enrolled for immediate (before weightbearing) postoperative MRI scans.Results:A total of 45 patients (16 male, 29 female; mean ± standard deviation age, 42.3 ± 12.9 years; body mass index, 31.6) were prospectively enrolled in the study; there were 47 meniscus root repairs: 29 medial and 18 lateral (2 with both). Postoperative MRI was obtained at an average of 6.3 months (range, 5.1-8 months); 98% of meniscal repairs had evidence of healing. Mean extrusion increased significantly, from 1.9 ± 1.5 mm preoperatively to 2.6 ± 1.4 mm postoperatively (P = .03). There was no significant progression of chondromalacia grade, subchondral edema, insufficiency fracture, subchondral cysts, or subchondral collapse. In the additional 10-patient cohort, the mean preoperative extrusion (1.6 ± 1.2 mm) was not significantly different from that immediately postoperatively (2.0 ± 1.0 mm; P = .23).Conclusion:Prospective MRI analysis of transtibial meniscus root repair confirmed a high rate of meniscal healing and no observable progression of cartilage degeneration or subchondral bone abnormalities at the short-term follow-up. However, meniscal extrusion worsened in the first 6 months after surgery.Registration:NCT03037242 (ClinicalTrials.gov identifier).

Peacock crown feather technique for oblique flap tear of the meniscus - Technical note

Options for meniscal repair are plenty, but optimal usage of these techniques is imperative to achieve meniscal healing and simultaneously minimize meniscal trauma. In this technical note, a particular suture configuration called the Peacock Crown feather stitch has been described especially for the oblique flap tears.

All-Inside Double-Sided Suture Repair for Longitudinal Meniscal Tears

The current consensus in the literature is that the meniscus must be saved. Even though inside-out sutures are still considered as the gold standard, the need to alternate between intra- and extra-articular structures for every stitch makes it laborious. New generations of all-inside systems are now routinely used in operating rooms and enable easier, quicker, and safer techniques. However traditional all-inside repair with limited upper fixation does not provide uniform compression from top to down, essential precondition for satisfactory meniscal healing. This Technical Note describes a simple and accessible alternative technique that provides stable fixation and overall compression of vertical meniscal tears from top to down with standard all-inside instrumentation.

Effect of concurrent repair of medial meniscal posterior root tears during high tibial osteotomy for medial osteoarthritis during short-term follow-up: a systematic review and meta-analysis

BackgroundMedial meniscal posterior root tears (MMPRTs) are frequently associated with medial compartment osteoarthritis, leading to loss of meniscal hoop tension. This study aimed to evaluate the efficacy of concurrent MMPRT repair during high tibial osteotomy (HTO) compared to HTO alone in patients with medial osteoarthritis and MMPRTs.MethodsThe MEDLINE/PubMed, EMBASE, and Cochrane Library databases were searched for studies reporting on concurrent MMPRT repair during HTO. Pre- and postoperative data were pooled to investigate the treatment effects of concurrent MMPRT repair during HTO, and compare postoperative clinical, radiological, and arthroscopic outcomes including cartilage status and healing event rates according to the arthroscopic classification of MMPRT healing (complete, partial [lax or scar tissue], or failed healing) between HTO patients with and without concurrent MMPRT repair. The random-effect model was used to pool the standardized mean differences, odds ratios (ORs), 95% confidence intervals (CIs), and event rates.ResultsSeven patient subgroups in six articles divided according to meniscal repair techniques were included in the final analysis. Concurrent MMPRT repair during HTO significantly improved the Lysholm score, while no intergroup differences were observed in the postoperative Lysholm and WOMAC scores, as well as radiological and arthroscopic outcomes. Those who underwent concurrent MMPRT repair showed a higher rate of complete meniscal healing (OR: 4.792, 95% CI, 1.95–11.79), with a pooled rate of complete meniscal healing of 0.327 (95% CI, 0.19–0.46).ConclusionConcurrent MMPRT repair during HTO for medial osteoarthritis with MMPRTs has little benefits on the clinical, radiological, and arthroscopic outcomes during short-term follow-up. Further accumulation of evidence is needed for long-term effects.

Postoperative external tibial rotation is correlated with inferior meniscal healing following pullout repair of a medial meniscus posterior root tear.

The purpose of this study was to evaluate the influence of tibial rotation on the postoperative healing status of the medial meniscus (MM) following pullout repair of the MM posterior root tear (MMPRT). Ninety-one patients (68 women and 23 men; mean age 63.3 ± 8.8years) who had undergone transtibial pullout repair of MMPRT were enrolled in the study. The tibial external rotation angle (ERA) in each patient was measured postoperatively using computed tomography in the extended knee position. The meniscal healing status following transtibial pullout repair was assessed by second-look arthroscopy (mean postoperative period 12months) using a previously published scoring system (range 0-10). The association between the ERA and the meniscal healing score was investigated using univariate linear regression models. The ERA cut-off for improved meniscal healing score (≥ 7) was determined using receiver-operating characteristic analysis. The ERA and the meniscal healing score were significantly associated, confirming that increased ERAs were correlated with worse meniscal healing status (R = - 0.28; P < 0.001). The optimum ERA cut-off value was 0.5°, with a sensitivity of 68% and a specificity of 63%. The mean meniscal healing scores were 7.3 and 6.2 among patients with ERAs < 0.5° and those with ERAs ≥ 0.5°, respectively (P < 0.001). This study demonstrated that the ERA was significantly correlated with the postoperative meniscal healing status. Postoperative tibial rotation could be one of the factors affecting postoperative outcomes of pullout repair of MMPRT. Controlling the tibial rotation may possibly improve meniscal healing. III.

Repair of a Complete Radial Tear of the Lateral Meniscus

Background: Recognizing and repairing a lateral meniscus complete radial tear is critical, as this tear pattern makes the meniscus nonfunctional for load sharing of axial forces, and the convex shape of the lateral tibial plateau increases contact pressure. Indications: The diagnosis of a lateral meniscus complete radial tear was supported by joint effusion, lateral joint line tenderness, positive McMurray test, and magnetic resonance imaging findings. Arthroscopy confirmed the complete radial tear. Technique Description: During the procedure, a self-capturing suture passer was used to pass a size 0 high-strength suture through the meniscus. To start the repair, the free ends of the suture were passed from top to bottom on both sides of the tear. These free ends were then crossed on the bottom of the meniscus to create an X configuration and passed from the bottom to top slightly further back from the first suture passes. A spinal needle and a chia were used from outside-in to create a side-to-side suture across the tear to reinforce the repair, and a knot was then tied on the outer capsule. The chia was used once again to shuttle the size 0 sutures to the exterior portion of the knee and the knots were tied on top of the capsule. Results: Postoperatively, patients are 25% weightbearing with a 0° to 90° range of motion restriction for 6 weeks, with no deep squatting for 3 months. With an isolated radial tear repair, the patient can expect to return to sport by 5 months. Radial tear repair outcomes demonstrate reduced lateral meniscus extrusion, complete meniscus healing in 86.4% of patients, and significantly improved International Knee Documentation Committee, Lysholm, and Tegner scores. Discussion/Conclusion: Repairing a complete radial tear of the lateral meniscus restores the function of the meniscus. This surgical technique provides a high rate of complete meniscus healing and excellent patient satisfaction.

Mid-term evaluation of clinical and functional outcomes after arthroscopic medial longitudinal and bucket-handle meniscus repair.

Objectives The aim of this study was to evaluate clinical and functional outcomes following the arthroscopic medial meniscal repair.Patients and methods A total of 50 patients (42 males, 8 females; mean age: 32.9±7.6 years; range, 17 to 48 years) who underwent arthroscopic repair for longitudinal and bucket-handle medial meniscal tears between March 2005 and October 2011 were retrospectively evaluated. The patients were divided into two groups as those having a longitudinal tear (patient group, n=31) and having a bucket-handle tear (control group, n=19). Preoperative and final follow-up functional outcomes were evaluated using the Lysholm Knee Score (LKS), International Knee Documentation Committee (IKDC) score, Tegner Activity Scale (TAS) score, and Knee Injury and Osteoarthritis Outcome Score (KOOS).Results The mean follow-up was 61.7±22.8 (range, 36 to 110) months. The mean preoperative LKS, IKDC score, TAS, and KOOS scores were significantly improved at the final postoperative follow-up (p<0.05). There was no significant difference in functional outcome scores between longitudinal and bucket-handle repairs (p>0.05), and isolated repairs and concomitant meniscal repair and anterior cruciate ligament reconstruction (p>0.05).Conclusion Arthroscopic meniscal repair provides similar mid-term functional and clinical outcomes for longitudinal and bucket-handle medial meniscal tears. Concomitant meniscal repair does not seem to affect meniscal healing.

Clinical Outcomes of Meniscus Repair with or without Multiple Intra-Articular Injections of Platelet Rich Plasma after Surgery.

Preservation of the meniscal volume is crucial in meniscus repair. The goal of this study was to evaluate the clinical outcome of repeated intra-articular platelet-rich plasma (PRP) injections after arthroscopic repair of a traumatic meniscal tear. We retrospectively reviewed 61 primary meniscal repairs in 61 patients (PRP group: 30; non-PRP: 31) from 2017 to 2018. Patients in the PRP group received repeated intra-articular PRP injections in week 2,4,6 after the primary meniscus repair. Subsequent meniscal repair treatment or meniscectomy, knee arthroplasty, and IKDC changes of less than 11.5 points were defined as healing failures. After following up for at least 24 months, the IKDC score was 75.1 ± 13.6, and the Lysholm score was 80.6 ± 14.9 in the PRP group and 72.6 ± 15.8 (IKDC) and 77.7 ± 17.2 (Lysholm) in the non-PRP group. Healing rates of the PRP and the non-PRP groups were 93.3% (Kaplan-Meier 91.6%) and 87.1% (Kaplan-Meier 84.7%), respectively (log rank test p = 0.874). Our study is the first to use multiple intra-articular PRP injections to facilitate meniscal healing after meniscal repair. Though selection bias may be present in this study, the PRP group had similar functional outcome and healing rate compared to non-PRP group.

Biomechanical study on different high-strength sutures and suture site for repairing posterior root tear of the medial meniscus

To compare biomechanical characteristic of different high-strength sutures and suture sites for repairing posterior root tear of the medial meniscus with modified Mason-Allen technique. Forty-eight specimen of medial meniscus of knee joint from fresh porcine (female, aged from 5 to 9 months with an average of 7 months) were chosen and established experimental model. The samples were divided into red zone fixation group and red-white zone fixation group according to suture sites, 24 in each group; and then were randomly divided into 3 subgroups which 8 in each group, and fixed with Ethibond suture, Ultrabraid suture and FiberWire suture, respectively. Biomechanical tests were performedon universal electromagnetic and mechanical testing machine. Each specimen was underwent 1 000 cyclic tests on the first time, then pull out test until failure. The maximum failure load, yield load, stiffness and displacement were analyzed. All specimen were successfully completed biomechanical tests. The failure mode of Ethibond group was caused by suture fracture; 6 cases of Ultrabraid suture group was caused by suture fracture which belong to red zone fixation group, 10 cases were caused by suture pull out, which 2 cases belong to red zone fixation group, 8 cases belong to red-white zone fixation group;8 cases of FiberWire group was caused by suture pull-out. Biomechanical test showed that:(1)In terms of suture strength, comparison of the maximum failure load, yield load and stiffness showed that Ethibond suture group <Ultrabraid suture group <FiberWire suture group, and had statistical differences among groups (P<0.05);comparison of cyclic displacement at 100, 500 and 1 000 cycles showed that Ethibond suturegroup>Ultrabraid suture group >FiberWire suture group, and had statistical differences among groups (P<0.05);the results showed the suture strength in Ethibond was the best, Ultrabraid suture took the second place, and FiberWire suture was the worst. (2)As for different suture sites, comparison of the maximum failure load, yield load and stiffness showed that red zone fixation group >red-white region fixation group, and had statistical difference between two groups(P< 0.05);comparison of cyclic displacement at 100, 500 and 1 000 cycles showed that red zone fixation group <red-white zone fixation group, and had statistical difference between two groups (P<0.05);the results showed that suture strength in red zone fixation group was better than that of red white zone fixation group. Mason-Allen suture could effectively fix posterior root tear of the medial meniscus and meet needs of early partial weight bearing after surgery. Suturing with Fiberwire in red zone is stronger and better for the meniscus healing and rehabilitation.

All-inside repair of bucket handle meniscus tears – Mid-term outcomes with postoperative magnetic resonance imaging

PurposeThe purpose of this study was to evaluate our results of bucket handle meniscus tear (BHMT) repairs with an all-inside repair technique using postoperative radiological imaging to evaluate meniscus reduction and healing and use them as criteria for evaluation of repair success. MethodsProspective recruitment of 20 patients with 21 BHMT repairs performed with an all-inside techniqueover a period from 2013 to 2015. All patients had an International Knee Documentation Committee (IKDC) Subjective Knee Form (SKF), Lysholm Score, Knee Injury and Osteoarthritis Outcome Score (KOOS) and Tegner Activity Level Scale obtained pre-operatively and at a minimum of 24 months after surgery. All patients had postoperative knee magnetic resonance imaging (MRI) performed between 18 and 24 months after surgery to assess the stability or failure of their repairs.At 5 years after surgery, the patients were assessed with regard to whether they had undergone repeat surgery or not. ResultsAt 2 years, the mean postoperative SKF, Lysholm and KOOS grand scores were 78.9, 88.5 and 86.8, respectively. The mean pre-injury Tegner Activity Scale was 7.6 and postoperatively it was 6.0. There was a significant difference in all pre- and postoperative outcome scores (P < 0.01).The postoperative MRIs showed that 19 of the 21 BHMT repairs had stable reduction of the tear fragment and two patients had displacement of the torn bucket handle fragment. At 5 years, one patient had undergone revision surgery. ConclusionBHMTs can be repaired with all-inside techniques with good results and successful outcomes.

Posterior knee arthroscopy facilitates the safe and effective all-inside repair of locked bucket-handle medial meniscal tear using a suture hook technique.

This study reported the outcomes of locked bucket-handle medial meniscal tear (BHMMT) repairs using an arthroscopic posterior approach during anterior cruciate ligament (ACL) reconstruction. Between 2011 and 2014, 48 patients with BHMMTs and ACL tears who met the eligibility criteria were enrolled in the present study. BHMMTs were assessed using a posterolateral transseptal portal and repaired using a posteromedial portal. Transportal ACL reconstruction was performed using hamstrings autograft. Patients were assessed based on their IKDC and Lysholm scores and Tegner activity level. Meniscal healing was clinically evaluated based on the absence of swelling, joint line tenderness, locking, and catching; McMurray test results; and the need for meniscectomy. According to follow-up assessments, the average IKDC and Lysholm scores improved significantly after 3-5years (P < 0.001) CONCLUSION: Excellent clinical outcomes were obtained when locked BHMMTs were repaired using an all-inside suture technique that employed posteromedial and posterolateral transseptal portals. IV.

Meniscal Salvage: Where We Are Today.

The menisci are fibrocartilaginous semilunar structures in the knee that provide load support. Injury to the meniscus alters its load sharing and biomechanical profile. Knee arthroscopy with meniscus débridement is the most common orthopaedic surgical procedure done in the United States. The current goals of meniscal surgery are to preserve native meniscal tissue and maintain structural integrity. Meniscal preservation is critical to maintain the normal mechanics and homeostasis of the knee; however, it is not always feasible because of the structure's poor blood supply and often requires removal of irreparable tissue with meniscectomy. Efforts have increasingly focused on the promotion of meniscal healing and the replacement of damaged menisci with allografts, scaffolds, meniscal implants, or substitutes. The purpose of this article was to review current and future meniscal salvage treatments such as meniscus transplant, synthetic arthroplasty, and possible bioprinted meniscus to allow patients to maintain quality of life, limit pain, and delay osteoarthritis.

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.

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.

Indirect Magnetic Resonance Arthrography May Help Avoid Second Look Arthroscopy for Assessment of Healing After Bucket Handle Medial Meniscus Repairs: A Prospective Clinico-Radiological Observational Study

The objectives were: (1) to analyze the MRI healing rates of bucket-handle meniscus repair; (2) to compare the accuracy of assessment ofmeniscus healing for conventional MRI and Indirect Magnetic Resonance Arthrography (IMRA); and (3) to identify patients who may requiresecond-look arthroscopy after meniscus repair. This is a prospective observational case series of thirty-seven patients with repaired bucket-handle medial meniscus tear with a minimum one year follow-up. Meniscus healing rates were assessed on direct MRI and IMRA using Henning's criteria. At the same time, patients' symptoms were evaluated according to Barrett's criteria and functional outcomes were recorded using International Knee Documentation Committee (IKDC) score, Knee Osteoarthritis and Outcomes Score (KOOS) and Tegner-Lysholm scores. A further clinical review was performed 18months after the imaging to assess the evolution of symptoms. At a mean of 22.3 ± 7.8months after the meniscus repair, 56.7% patients showed complete healing and 40.5% patients demonstrated incomplete repair healing on IMRA. 52% patients with complete healing and 40% patients with incomplete healing demonstrated meniscus symptoms. At the second clinical review, 19% patients with complete healing and 20% patients with incomplete healing had meniscus symptoms. There was no co-relation between symptoms, PROMs and healing on MRI. Indirect MR arthrography offers distinct advantages over direct MRIfor assessment of meniscus healing, especially in symptomatic patients. Patient-reported outcome measures and symptomatology are not co-related with the healing status of the meniscus and they resolve in the majority on longer follow-up. A more conservative approach guided by IMRA to assess meniscus healing will avoid early re-operations.

Development of a novel meniscal sheet scaffold and its effectiveness for meniscal regeneration in a rabbit defect model.

This study evaluated the biomechanical strength of a novel two-layer meniscal sheet scaffold (MSS) consisting of polyglycolic acid and poly-Llactic acid/caprolactone and investigated meniscal healing using wrapping treatment for meniscal defect model in a rabbit. The ultimate failure load of the MSS was determined using a tensile testing machine, in vitro. A 2-mm cylindrical defects were created at the medial meniscus of rabbit knees (n = 40). Each knee was assigned to one of two groups. The defect group was not treated and the MSS group underwent wrapping treatment with MSS. Menisci were harvested at 2, 4, 8, and 12 weeks post-implantation. The regenerated meniscus and defect size were evaluated using macrophotographs. Ishida scores for regenerated tissue were determined using Safranin-O/Fast Green staining. Immunohistochemical analysis of Ki-67 for cell proliferation, anti-type I and II collagen antibodies for structure of the regenerated tissue was elucidated. Medial femoral cartilage was stained with Safranin-O/Fast Green and evaluated with Osteoarthritis Research Society International (OARSI) scores. The strength of MSS was maintained over 90% from initial time point to 4 weeks after hydrolysis and over 60% of the strength remained at 8 weeks. The surface area of the meniscus was larger and the defect size smaller in the MSS group than in the defect group at 8 and 12 weeks. Ishida scores revealed that the MSS group improved significantly compared to that of the defect group at all postsurgery time points evaluated. Ki-67 positive cell ratio was significantly higher in the MSS group. OARSI score of the defect group was significantly higher and the defect group showed progressive degeneration in the articular cartilage from 8 to 12 weeks. Overall, wrapping meniscus defects with MSS was useful for accelerating meniscal healing from an early stage and beneficial for tissue regeneration and promoting extracellular matrix maturation.