Meniscal Healing Research Articles

Pulsed Electromagnetic Field Enhances Healing of a Meniscal Tear and Mitigates Posttraumatic Osteoarthritis in a Rat Model

Background: Meniscal tears in the avascular region are thought to rarely heal and are a considerable challenge to treat. Although the therapeutic effects of a pulsed electromagnetic field (PEMF) have been extensively studied in a variety of orthopaedic disorders, the effect of a PEMF on meniscal healing has not been reported. Hypothesis: PEMF treatment would promote meniscal healing and prevent osteoarthritis progression. Study Design: Controlled laboratory study. Methods: A total of 72 twelve-week-old male Sprague-Dawley rats with full-thickness longitudinal medial meniscal tears in the avascular region were divided into 3 groups: control (Gcon), treatment with a classic signal PEMF (Gclassic), and treatment with a high–slew rate signal PEMF (GHSR). Macroscopic observation and histological analysis of the meniscus and articular cartilage were performed to evaluate the meniscal healing and progression of osteoarthritis. The synovium was harvested for histological and immunofluorescent analysis to evaluate the intra-articular inflammation. Meniscal healing, articular cartilage degeneration, and synovitis were quantitatively evaluated according to their scoring systems. Results: Dramatic degenerative changes of the meniscus and articular cartilage were noticed during gross observation and histological evaluation in Gcon at 8 weeks. However, the menisci in the 2 treatment groups were restored to normal morphology, with a smooth surface and shiny white color. Particularly, the HSR signal remarkably enhanced the fibrochondrogenesis and accelerated the remodeling process of the regenerated tissue. The meniscal healing scores of the PEMF treatment groups were significantly higher than those in Gcon at 8 weeks. Specifically, the HSR signal showed a significantly higher meniscal repair score than did the classic signal at week 8 (P < .01). Additionally, the HSR signal significantly downregulated the secretion levels of interleukin 1 beta (IL-1β) and tumor necrosis factor alpha (TNF-α) in the meniscus and synovium as compared with the control group. When compared with the 2 treatment groups, Gcon had significantly higher degeneration scores (Gcon vs Gclassic, P < .0001; Gcon vs GHSR, P < .0001). The HSR signal also exhibited significantly lower synovitis scores compared with the other two groups (Gcon vs Gclassic, P < .0001; Gclassic vs GHSR, P = .0002). Conclusion: A PEMF promoted the healing of meniscal tears in the avascular region and restored the injured meniscus to its structural integrity in a rat model. As compared with the classic signal, the HSR signal showed increased capability to promote fibrocartilaginous tissue formation and modulate the inflammatory environment, therefore protecting the knee joint from posttraumatic osteoarthritis development. Clinical Relevance: Adjuvant PEMF therapy may offer a new approach for the treatment of meniscal tears attributed to the enhanced meniscal repair and ameliorated osteoarthritis progression.

Arthroscopic Meniscal Healing following Medial Meniscus Posterior Root Repair: A Comparison between Two Suture Materials.

Recently, transtibial pullout repair of the medial meniscus (MM) posterior root tear (PRT) has become widely accepted and provides satisfactory clinical outcomes. Widening after cyclic loading or ultimate failure load using different suture materials and configurations has been studied. However, no study has compared the clinical outcomes using different suture materials. This study aimed to evaluate the clinical outcomes after performing MMPRT pullout repair using different suture materials. We hypothesized that better clinical outcomes would be achieved using ultra-high molecular weight polyethylene (UHMWPE) tape compared with a normal polyester suture. Thirty-seven patients who underwent MM posterior root repair between November 2019 and May 2020 were retrospectively investigated. Pullout repair was performed using a hollow no. 0 polyester suture (n = 14) and UHMWPE tape (n = 23). Clinical outcomes were assessed preoperatively and at 1 year postoperatively, using the Lysholm knee score, Knee Injury and Osteoarthritis Outcome Score, and visual analogue scale (VAS) pain score. The meniscal healing status was assessed using an arthroscopic scoring system (range: 0-10). All clinical scores were improved significantly in both groups. However, significantly higher meniscal healing scores and decreased VAS pain scores were observed in the UHMWPE group (7.3 ± 0.9 and 7.7 ± 11.3, respectively) than in the polyester group (5.6 ± 2.1 and 18.4 ± 18.6, respectively; p < 0.01). Suture cut-out and loss of the root continuity were observed in some cases (three cases [21.4%] in the polyester suture group and one case [4.3%] in the UHMWPE tape group). Both suture materials led to satisfactory clinical outcomes at 1 year postoperatively, whereas the UHMWPE tape was useful for obtaining good meniscal healing and decreasing the VAS pain score.

Meniscus treatment: biological augmentation strategies: a narrative review.

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. 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. 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. 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.

Single-stage repair of displaced bucket-handle meniscal tears with anterior cruciate ligament reconstruction leads to good meniscal survivorship : a retrospective cohort study.

The best surgical strategy for the management of displaced bucket-handle (BH) meniscal tears in an anterior cruciate ligament (ACL)-deficient knee is unclear. Combining meniscal repair with ACL reconstruction (ACLR) is thought to improve meniscal healing rates; however, patients with displaced BH meniscal tears may lack extension. This leads some to advocate staged surgery to avoid postoperative stiffness and loss of range of motion (ROM) following ACLR. We reviewed the data for a consecutive series of 88 patients (mean age 27.1 years (15 to 49); 65 male (74%) and 23 female (26%)) who underwent single-stage repair of a displaced BH meniscal tear (67 medial (76%) and 21 lateral (24%)) with concomitant hamstring autograft ACLR. The patient-reported outcome measures (PROMs) EuroQol visual analogue scale (EQ-VAS), EuroQol five-dimension health questionnaire (EQ-5D), Knee injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee score (IKDC), and Tegner score were recorded at final follow-up. A Kaplan-Meier survival analysis was performed to estimate meniscal repair survivorship. Analyses were performed with different cut-offs for meniscal and ACL injury-to-surgery time (within three weeks, three to ten weeks, and more than ten weeks). Meniscal repair survivorship at a median final follow-up of 55 months (interquartile range (IQR) 24 to 91) was 82% (95% confidence interval 70 to 89). A total of 13 meniscus repairs failed (12 requiring meniscectomy and one requiring a further meniscal repair). At final follow-up, median PROMs were: EQ-VAS 85 (IQR 75 to 90), EQ-5D Index 0.84 (IQR 0.74 to 1.00), KOOS Pain 89 (IQR 80 to 94), KOOS Symptoms 82 (IQR 71 to 93), KOOS Activities of Daily Living 97 (IQR 91 to 100), KOOS Sport and Recreation 80 (IQR 65 to 90), KOOS Quality of Life 69 (IQR 53 to 86), IKDC 82.8 (IQR 67.8 to 90.8), and Tegner 6 (IQR 4 to 7). Two patients underwent revision ACLR following further injuries. One patient had an arthroscopic washout for infection at 11 days post-BH meniscal repair/ACLR. Four patients (4.5%) required a further procedure for stiffness, reduced ROM, and pain, and all were operated on within three weeks of meniscal injury. There was no difference in the interval between meniscal injury and surgery between repairs that failed and those that survived. These data suggest that concomitant ACLR with repair of displaced BH meniscal tears, even if they have been displaced for some time, appears to afford satisfactory PROMs and good survivorship. Repairs within three weeks of meniscal injury may be associated with higher rates of postoperative reintervention for stiffness. Cite this article: Bone Joint J2022;104-B(6):680-686.

Clinical outcomes, healing rate, and presence of peri-meniscal cysts after all-inside meniscal repair in combination with anterior cruciate ligament reconstruction: a prospective comparative study with magnetic resonance imaging assessment.

Meniscal repairs are the most common associated procedures during ACL reconstruction, but they present challenging indications and possible risks of complications or failures. The aim of the present study is to assess the clinical outcomes of all-inside meniscal repairs in the setting of ACL reconstruction. Twenty patients with ACL reconstruction and all-inside meniscal repair were compared to 20 patients with isolated ACL reconstruction. All patients were prospectively evaluated pre-operatively, at fourmonth, and 18-month follow-up with KT-1000, Kira accelerometer for pivot-shift, KOOS, Marx score, and SF-36. Meniscal healing and presence of peri-meniscal cysts were assessed on standardized 1.5-T MRIs performed at 18months. Twenty-one meniscal repairs were performed in 20 patients (81% medial, 19% lateral). At 18months, 48% had complete healing, 38% had incomplete healing, and 14% had no healing. Peri-meniscal cysts were present in 33% of cases. Worst pre-operative KOOS pain (p = 0.0435) and ADL (p = 0 .0201) were present in patients with meniscal lesion, while no differences were present at fourmonths and 18months between patients with or without meniscal repair (p > 0.05). No significant differences were noted stratifying patients according to meniscal healing or cyst presence, except of a lower Qol KOOS subscale in patients with peri-meniscal cysts (p = 0.0430). Meniscal repairs produced good short-term results when performed in combination to ACL reconstruction. Full or partial healing at MRI was present in 86% of cases. One patient out of three developed peri-meniscal cysts.

Meniscal Repair Outcomes at &gt;5 Years: A Systematic Review and Meta-Analysis

Introduction:Meniscal repair techniques (inside-out, all-inside, outside-in) continue to evolve. Assessment of meniscus repair outcomes at a minimum of 5 years postoperatively appears to best represent the true failure rates compared to 1 and 2-year timepoints. In the last decade, the literature on outcomes of meniscus repair has grown significantly.Purpose:To conduct a systematic review and meta-analysis to assess the rate of failure after meniscal repair at a minimum 5 years postoperatively.Methods:We performed a systematic review of studies reporting the outcomes of meniscal repair at a minimum of 5 years postoperatively. A standardized search strategy was utilized with the assistance of a medical librarian. s and full-text articles were reviewed by two reviewers to identify studies assessing the clinical outcome of meniscus repair, which was most uniformly assessed by reoperation. Outcomes were assessed (when reported) relative to anterior cruciate ligament (ACL) status, sex, age, and postoperative rehabilitation protocol. Pooling of data and meta-analysis with a random-effects model were performed.Results:A total of 28 studies of 1712 patients were included. In the last decade, 15 studies of 1168 patients have been reported, compared to 566 patients in 13 studies in the previous decade. The pooled failure rate of all devices was 22.2% (365/1712) and the failure rates of modern repairs was 17.5% (194/1128). Medial repairs were significantly more likely to fail compared to lateral repairs (26.4% [178/745] v. 13.0% [55/365], p=0.01). Failure rates varied from 16.9% for inside-out (78/501), 16.2% modern all-inside (66/396), 20.2% for outside-in (34/153), and 19.8% for open (22/109). First generation all-inside devices had a significantly higher failure rate (30.3%) compared to modern all-inside devices (16.2%) (p=0.01). There was no significant difference in failure rates between meniscal repair with concomitant ACL reconstruction (19.0%) and isolated meniscal repairs (19.6%, p=0.780). There was also no difference between post-operative rehabilitation protocols, sex, or age (all p>0.05).Conclusions:The outcomes of meniscal repair at a minimum 5 years postoperatively had an overall failure rate of 21.8%. Modern all-inside meniscus repair techniques appear to have improved the success rates compared to first-generation all-inside devices, and now appear similar to those of inside-out meniscus repair. Lateral repairs were significantly more likely to be successful compared to medial repairs. Finally, despite traditional teaching that ACL reconstruction improves rates of meniscus healing, across ˜700 patients, no difference in rates of healing were seen in ACL reconstruction compared to isolated meniscus repair.Figure 1.Scatter Plot of the failure rate reported by the study compared time of follow up completed. Each study is represented by a dot, the size of which represents the indivudual study’s sample size. A simple linear regression line of best fit is shown (R2=0.02).Figure 2.Forest plot demonstrating failure rates sorted by the technique of repair used. All inside divices were subdivided into first generation (meniscal arrows) and modern (defined as 2nd generation and newer). Other techniques include inside out, outside in, and open.Es=Estimated significance; 95% CI-95% Confidence interval.

Inside-Out Approach to Meniscus Repair: Still the Gold Standard?

The purpose of this review is to provide an up-to-date summary on the current literature and trends regarding use of the inside-out approach to meniscus repair. Additionally, the paper describes the authors preferred techniques for inside-out meniscus repair utilizing posteromedial and posterolateral exposures. There has been a substantial increase in recent publications regarding meniscus repair. However, comparisons regarding the optimal repair technique have not been conclusive. Despite the recent increase in use of all-inside devices, multiple investigations with short-to-mid-term follow-up have demonstrated similar rates of meniscus healing between inside-out and all-inside repair techniques. Similarly, current literature describes comparable failure rates of around 20%. There are variations in the profile of complications, with all-inside devices having more implant-related complications and inside-out techniques with higher neurovascular injuries. Inside-out meniscus repair is a versatile, cost-effective technique that remains the gold standard for management of most meniscus tear patterns. Through a thoughtful approach, efficient suture retrieval and repair can be performed while protecting critical neurovascular structures. All-inside meniscus repair devices have increased in popularity and surgeon access, but this technique is not without limitations and comparisons to inside-out meniscus repair demonstrates equivocal outcomes.

Large lateral tibial slope and lateral-to-medial slope difference are risk factors for poorer clinical outcomes after posterolateral meniscus root tear repair in anterior cruciate ligament reconstruction

BackgroundMeniscus root tear is an uncommon but detrimental injury of the knee. Hoop stress is lost during meniscus root tear, which can lead to excessive tibiofemoral contact pressure and early development of osteoarthritis. Posterolateral meniscus root tears (PLRT) are more commonly associated with anterior cruciate ligament (ACL) tears. As the lateral compartment is less congruent than the medial compartment, it is more susceptible to a shearing force, which is increased in the ACL-deficient knee. In accordance with the compressive axial load, the increase in the tibial slope would generate a greater shearing force. The additional lateral compartment mobility caused by ACL tear should be reduced after ACL reconstruction (ACLR). However, there is a lack of evidence to conclude that ACLR can sufficiently limit the effect of large tibial slope (LTS) on the healing after PLRT repair. This study aimed to evaluate whether a steep LTS would be a risk factor for poorer clinical outcomes after PLRT repair concomitant with ACLR.MethodsIn this retrospective study, a chart review was conducted to identify patients with concomitant unilateral primary ACLR and PLRT repair. Patients with a partial tear or healed tear were excluded. Postoperative MRI and clinical assessments were performed at a mean follow up of 35 months. MRI data was used to measure the LTS, medial tibial slope (MTS), coronal tibial slope (CTS), the lateral-to-medial slope difference (LTS-MTS) and meniscus healing and extrusion. Functional outcomes were evaluated by patient-reported outcomes (International Knee Documentation Committee [IKDC], Lysholm and Tegner scores) and KT-1000 arthrometer assessment. Interobserver reproducibility was assessed by two reviewers.ResultsTwenty-five patients were identified for the analysis. Patients with larger LTS and larger LTS-MTS differences were shown to be correlated with poorer IKDC scores after surgery (R = -0.472, p = 0.017 and R = -0.429, p = 0.032, respectively). Herein, patients with LTS ≥ 6° or LTS-MTS ≥ 3° demonstrated poorer IKDC scores.ConclusionA large LTS (≥ 6°) and a large difference of LTS-MTS (≥ 3°) were shown to be risk factors for poorer functional and radiological outcomes for PLRT repair in patients after ACLR. Clinically, closer monitoring and a more stringent rehabilitation plan for patients with LTS ≥ 6° or LTS-MTS ≥ 3° would be recommended.

The Prospect Science of Meniscus Preservation

The meniscus plays a role in stabilizing (secondary) knee joints by load transmission and reducing the contact stresses on knee joint cartilage. Meniscal tear more commonly involves the young patient and may be associated with ligament injuries. Meniscal injury also can be associated with some congenital anomaly. The meniscus injury treatment is challenging and most commonly treated with excision.Excision of the meniscus is associated with poor clinical outcomes, and high chance of early cartilage degeneration. Current meniscus repair techniques are still associated with common re-admission for surgery and poor clinical outcomes. To improve the patient- reported outcomes, the current basic research project should focus on enhancing meniscus healing and replacing meniscus tears.

Overview of posterior knee arthroscopy in the medial meniscal repair: Technical note

Preservation of the meniscus in bucket handle medial meniscal tears (BHMMTs) and posterior meniscocapsular (ramp) lesions is challenging. Current efforts are being made in the scientific community to (1) introduce new ways of gaining easier and better field of view over the repair site and (2) increase the chance of meniscal healing through effective augmentation procedures. The current note introduces a way to achieve good exposure of posterior knee compartments and proposes an augmentation technique that involves exposing the local non-articulating subchondral cancellous bone and making in situ clots.

The Functional Outcome of Simultaneous Anterior Cruciate Ligament Reconstruction with Meniscus Repair

Background: Meniscal repair is performed in an attempt to prevent post-traumatic arthritis resulting from meniscal dysfunction after meniscal tears. The socio-economic implications of premature arthritis are significant in the young patient population. Investigations and techniques focusing on meniscus preservation and healing are now at the forefront of orthopaedic sports medicine. Methods: All unilateral primary ACL reconstructions in a prospective cohort who had meniscal repair at the time of ACLR were evaluated. Validated patient oriented outcome instruments were completed preoperatively and then again at follow up. Results: 65 unilateral primary ACL reconstructions were performed concomitant meniscal repairs during the study period. Patient follow-up was obtained, allowing confirmation of meniscal repair success (defined as no repeat arthroscopic procedure) or failure. Conclusions: Meniscal repair is a successful procedure in conjunction with ACL reconstruction. When confronted with a “repairable” meniscal tear at the time of ACL reconstruction, orthopaedic surgeons can expect an estimated &gt;90% clinical success rate using a variety of methods as shown in our study.

Prospective Consecutive Clinical Outcomes After Transtibial Root Repair for Posterior Meniscal Root Tears: A Multicenter Study.

Background:Prospective evaluation of clinical outcomes after posterior meniscal root repair utilizing a transtibial pullout technique is limited, and factors that may contribute to outcomes are unclear.Hypothesis:It was hypothesized that there would be an overall significant improvement in outcomes after root repair and that differences in clinical outcomes would correlate with age, body mass index (BMI), sex, and meniscal extrusion.Study Design:Case-control study; Level of evidence, 3.Methods:Consecutive patients undergoing transtibial medial or lateral meniscal root repair were enrolled prospectively at 2 orthopaedic centers between March 2017 and January 2019. Pre- and postoperative magnetic resonance imaging (MRI) were obtained to assess for meniscal healing, quantification of extrusion, articular cartilage grade, and subchondral bone changes. Patient-reported outcomes including International Knee Documentation Committee (IKDC) scores, Tegner activity scale, and visual analog scale (VAS) for pain were collected preoperatively and 2 years postoperatively. Patients were then subdivided by clinical and demographic characteristics to determine factors associated with clinical outcomes.Results:Included were 45 patients (29 female, 16 male; mean age, 42.3 ± 12.9 years; mean BMI, 31.6 kg/m2) who underwent 47 meniscal root repairs (29 medial and 16 lateral; 2 had both). Significant improvements at 2-year follow-up were seen in IKDC score (41.1 vs 78.4; P < .001), Tegner activity level (3 vs 4; P < .001), and VAS pain (2.8 vs 0.7; P < .001). BMI, preoperative malalignment, cartilage status, and progressive meniscus extrusion (Δ = 0.7 mm) did not have a negative impact on IKDC and Tegner scores 2 years postoperatively. Age greater than or equal to 50 years and extrusion pre- and postoperatively were associated with decreased Tegner scores. Progressive meniscal extrusion was associated with a decreased overall improvement in Tegner scores.Conclusion:Transtibial root repair for medial and lateral posterior meniscal root tears demonstrated significantly improved clinical outcomes at 2 years postoperatively. Increased age, increased BMI, cartilage status, and meniscal extrusion did not have a negative impact on short-term functional outcomes (IKDC), but age greater than or equal to 50 years and extrusion negatively influenced patient activity level (Tegner).Registration:NCT03037242 (ClinicalTrials.gov identifier).

Histologically Confirmed Recellularization is a Key Factor that Affects Meniscal Healing in Immature and Mature Meniscal Tears.

Healing outcomes of meniscal repair are better in younger than in older. However, exact mechanisms underlying superior healing potential in younger remain unclear from a histological perspective. This study included 24 immature rabbits and 24 mature rabbits. Tears were created in the anterior horn of medial meniscus of right knee in each rabbit. Animals were sacrificed at 1, 3, 6, and 12 weeks postoperatively. We performed macroscopic and histological evaluations of post-meniscal repair specimens. Cells were counted within a region of interest to confirm cellularization at tear site in immature menisci. The width of cell death zone was measured to determine the region of cell death in mature menisci. Apoptosis was evaluated by TUNEL assay. Vascularization was assessed by CD31 immunofluorescence. The glycosaminoglycans and the types 1 and 2 collagen content was evaluated by calculating average optical density of corresponding histological specimens. Cartilage degeneration was also evaluated. Healing outcomes following untreated meniscal tears were superior in immature group. Recellularization with meniscus-like cell morphology was observed at tear edge in immature menisci. Superior recellularization was observed at meniscal sites close to joint capsule than at sites distant from the capsule. Recellularization did not occur at tear site in mature group; however, we observed gradual enlargement of cell death zone. Apoptosis was presented at 1, 3, 6, 12 weeks in immature and mature menisci after untreated meniscal tears. Vascularization was investigated along the tear edges in immature menisci. Glycosaminoglycans and type 2 collagen deposition were negatively affected in immature menisci. We observed glycosaminoglycan degradation in mature menisci and cartilage degeneration, specifically in immature cartilage of the femoral condyle. In conclusion, compared with mature rabbits, immature rabbits showed more robust healing response after untreated meniscal tears. Vascularization contributed to the recellularization after meniscal tears in immature menisci. Meniscal injury fundamentally alters extracellular matrix deposition.

Stem cells application in meniscal tears: a systematic review of pre-clinical and clinical evidence.

Conservative and surgical treatments for meniscal lesions are various and this field of orthopedic surgery is in continuous development. Stem cells represent one of the current options to stimulate meniscal healing. The present systematic review aimed at summarizing the state of art in the application of stem cells for the treatment of meniscal damage both at pre-clinical and clinical level. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were followed to perform this systematic review. A systematic search was performed using the PubMed (MEDLINE), EMBASE and Cochrane Library databases. All the studies dealing with the application of stem cells as a treatment for meniscal tears were pooled, data were extracted and analyzed. The studies were divided into two groups (pre-clinical and clinical), and then, discussed independently. A total of 18 studies were included. Thirteen were classified as "pre-clinical" and five as "clinical". The most commonly used cells were mesenchymal stem cells (MSC), derived from bone marrow (BMMSC), synovial tissue (SMSC), or adipose tissue (ADSC). Follow-ups ranged from 2 to 16 weeks for the pre-clinical studies and from 3 to 24 months for the clinical studies. All studies documented good results in terms of laboratory markers/scores, clinical and radiologic evaluation. Based on the currently available data, it is not possible to establish the best cell source or delivery method for the treatment of meniscal injuries. Bone Marrow derived stem cells delivered through injection represent the most studied approach, with the most promising results. However, the full impact of these therapies through their different sub-type of stem cells and implantation techniques still needs to be critically analyzed through larger randomized controlled trials with longer follow-up.

Repairing Complete Radial Tears of the Lateral Meniscus: Arthroscopic All-Inside Double Vertical Cross-Suture Technique Is Effective and Safe With 2-Year Minimum Follow-Up

To assess the failure rate and clinical outcomes of the all-inside, double-vertical, cross-suture technique in repairing complete radial tears of the lateral meniscus. We retrospectively reviewed records of patients with this injury on whom the present technique was employed at our institution between 2011 and 2018, with at least 24 months of follow-up. Six months postoperatively, the meniscus healing and extrusion status were evaluated through magnetic resonance imaging. Preoperative and postoperative knee function, measured through IKDC, Lysholm knee, and Tegner activity scale scores, were compared. In total, 27 patients underwent the procedure. The preoperative mean (standard deviation) IKDC score, Lysholm knee score, and Tegner activity scale scores were 53.4 ± 5.3, 63.2 ± 9.3, and 4± .7, respectively. At the last follow-up (≥24 months postoperatively), these scores increased to 92.1 ± 2.6, 90.8 ± 4.2, and 6.1 ± 1.3, respectively (all P < .05). Complete healing of the meniscus was observed in 23 patients, and 4 patients had meniscus retear or nonhealing. The overall retear or nonhealing rate was 14.8%. Healing rates between those with isolated radial tears (87.5%) and those with combined anterior cruciate ligament rupture (84.2%; P= .826) were comparable. No difference was observed in the progression of coronal and sagittal meniscus extrusion (P= .133 and .797, respectively). In patients with complete radial tears of the lateral meniscus, the arthroscopic all-inside double vertical cross-suture repair technique resulted in an 85.2% healing rate, improvements in functional outcomes and activity levels, and no identifiable progression of meniscus extrusion. The all-inside double vertical cross-suture technique is effective and safe for the repair of radial tears of the meniscus. Level IV, retrospective case series.

Good Clinical Success Rates Are Seen 5 Years After Meniscal Repair in Patients Regularly Undertaking Extreme Flexion

PurposeTo report the functional and radiologic outcomes of meniscal repair healing in a cohort of patients with a high demand for loaded extreme flexion angles after undergoing meniscal repair.MethodsWe performed a retrospective clinical and radiologic evaluation of patients who perform extreme knee flexion activities on a daily basis at a minimum follow-up of 2 years after meniscal repair. International Knee Documentation Committee, Lysholm, and Tegner scores were obtained, and clinical examinations and radiologic (magnetic resonance imaging and radiography) evaluations were performed.ResultsOf 47 eligible patients, 39 patients (40 knees) were available for review with an average follow-up time of 5 years (range, 2-9 years). The average age was 26.7 years (range, 19-39 years); 38 patients were men. The average time from injury to surgery was 20.9 months (range, 3 days to 120 months). Associated anterior cruciate ligament injury was present in 31 knees, but only 20 underwent simultaneous anterior cruciate ligament surgery. The mean International Knee Documentation Committee score was 88.9 (range, 53-99). The mean Lysholm score was 90.9 (range, 48-100). The mean Tegner activity level dropped from 6.18 before injury to 5.51 at the time of evaluation. According to the Barrett criteria for clinical outcomes, complete healing was observed in 29 of 40 knees (72.5%). There was a statistically significant correlation between the functional outcomes and the clinical outcomes (P = .008). On magnetic resonance imaging, 22 of 38 knees (57.9%) showed completely healed menisci.ConclusionsThe results of this study suggest that loaded deep knee flexion may be safe after a period of restricted rehabilitation, and clinical and radiologic tissue healing is independent of the overall functional outcome.Level of EvidenceLevel IV, case series with subgroup analysis.

Effects of Platelet-Rich Plasma and Bone Marrow Mesenchymal Stem Cells on Meniscal Repair in the White-White Zone of the Meniscus.

ObjectiveTo investigate the role of autologous platelet‐rich plasma (PRP) on the repair of meniscal white‐white zone injury through promoting the proliferation of canine bone marrow‐derived mesenchymal stem cells (BMSCs).MethodsA total of 24 beagle dogs were selected to construct meniscal white‐white zone injury models in both lateral knee joints. All subjects were divided into four groups: control, BMSCs, PRP, and PRP + BMSCs. Immunohistochemistry was applied in the expression detection of type I and type II collagens. HE staining and methylene blue staining were performed to observe the injury of cartilage of lateral femoral condyle in each group. ELISA was used to detect the osteopontin (OPN) content in cartilage of lateral femoral condyle. HE staining and magnetic resonance imaging (MRI) were used to observe the healing of meniscus in each group. Outcome measures include the expression of OPN in the synovial fluid of knee joint, the expression of type I collagen and type II collagen, the healing of meniscus injury, and the damage degree of lateral femoral condyle cartilage.ResultsCompared with the control group, the expressions of type I and type II collagens were enhanced in the PRP group and the PRP + BMSCs group. Compared with 1 week before modeling, the expression of OPN was elevated in the control group and the BMSCs group at 3 weeks after modeling. There were no significant differences in the above indicators between the PRP group and the PRP + BMSCs group. According to MRI and pathological section after HE staining, meniscal healing in the PRP group and the PRP + BMSCs group was significantly improved as compared to that of the control group and the BMSCs group (all P < 0.05), and there was no significant difference between the PRP group and the PRP + BMSCs group (P > 0.05). All subjects were divided into the non‐healing group and the healing group in accordance with the HE staining results in previous experiment. The injury of cartilage of lateral femoral condyle was significantly heavier in the non‐healing group than that in the healing group.ConclusionThe application of PRP alone or in combination with BMSCs could promote the clinical healing rate of meniscal white‐white zone injury.

Biomaterials and Meniscal Lesions: Current Concepts and Future Perspective.

Menisci are crucial structures for knee homeostasis. After a meniscal lesion, the golden rule, now, is to save as much meniscus as possible; only the meniscus tissue that is identified as unrepairable should be excised, and meniscal sutures find more and more indications. Several different methods have been proposed to improve meniscal healing. They include very basic techniques, such as needling, abrasion, trephination and gluing, or more complex methods, such as synovial flaps, meniscal wrapping or the application of fibrin clots. Basic research of meniscal substitutes has also become very active in the last decades. The aim of this literature review is to analyze possible therapeutic and surgical options that go beyond traditional meniscal surgery: from scaffolds, which are made of different kind of polymers, such as natural, synthetic or hydrogel components, to new technologies, such as 3-D printing construct or hybrid biomaterials made of scaffolds and specific cells. These recent advances show that there is great interest in the development of new materials for meniscal reconstruction and that, with the development of new biomaterials, there will be the possibility of better management of meniscal injuries

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.