The 6-m timed hop test is a prognostic factor for outcomes in patients with meniscal tears treated with exercise therapy or arthroscopic partial meniscectomy: a secondary, exploratory analysis of the Odense-Oslo meniscectomy versus exercise (OMEX) trial.

PURPOSE: To identify the prognostic factors for 2-year patient-reported outcomes in middle-aged patients with degenerative meniscal tears treated with exercise therapy (ET) or arthroscopic partial meniscectomy (APM). METHODS: One hundred and seven patients, with mean age 49.6 (SD 6.2) years and BMI 25.7 (SD 3.7), were included in this analysis of data from the OMEX trial ( http://www.clinicaltrials.gov NCT01002794). Linear and Poisson regression models were built to explore the associations between potential prognostic factors (patient characteristics, knee function-related and disease-related factors) and 2-year patient-reported outcomes: the Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales Pain, Symptoms, ADL, Sport/Rec, QoL and 5-point Global Rating of Change scales for knee pain (GRC Pain) and function (GRC Function). Analyses were performed for the whole cohort and for the two treatment groups (n = 55 and 52) with adjustments for age, sex, BMI and baseline KOOS. RESULTS: For the whole cohort, a 1-s better baseline 6-m timed hop test result was associated with 3.1-7.1 points better 2-year scores for all KOOS subscales (95% CIs 1.1-5.2 to 4.1-10.1 points). A 1.61-2.80 s better test was associated with scores equivalent to previously calculated clinical relevant differences for each KOOS subscale. For the groups of patients treated with ET and APM, respectively, 2.09-3.60 s and 0.63-1.99 s better tests were associated with clinical relevant differences. For the whole cohort, a 1-s better test was associated with 26% (95% CI 15-38%) and 22% (95% CI 11-34%) higher possibility for better or much better GRC Pain and Function scores. Patients treated with ET had 17% (95% CI 2-33%) increased possibility for better or much better GRC Pain score, and patients treated with APM had 65% (95% CI 32-108%) and 70% (95% CI 38-109%) increased possibility for better or much better GRC Pain and Function scores. CONCLUSIONS: The 6-m timed hop test result was a significant prognostic factor for 2-year patient-reported outcomes in middle-aged patients with degenerative meniscal tears, especially in those treated with APM. LEVEL OF EVIDENCE: II.

Hydrogels for precision meniscus tissue engineering: a comprehensive review.

The meniscus plays a pivotal role to preserve the knee joint homeostasis. Lesions to the meniscus are frequent, have a reduced ability to heal, and may induce tibiofemoral osteoarthritis. Current reconstructive therapeutic options mainly focus on the treatment of lesions in the peripheral vascularized region. In contrast, few approaches are capable of stimulating repair of damaged meniscal tissue in the central, avascular portion. Tissue engineering approaches are of high interest to repair or replace damaged meniscus tissue in this area. Hydrogel-based biomaterials are of special interest for meniscus repair as its inner part contains relatively high proportions of proteoglycans which are responsible for the viscoelastic compressive properties and hydration grade. Hydrogels exhibiting high water content and providing a specific three-dimensional (3D) microenvironment may be engineered to precisely resemble this topographical composition of the meniscal tissue. Different polymers of both natural and synthetic origins have been manipulated to produce hydrogels hosting relevant cell populations for meniscus regeneration and provide platforms for meniscus tissue replacement. So far, these compounds have been employed to design controlled delivery systems of bioactive molecules involved in meniscal reparative processes or to host genetically modified cells as a means to enhance meniscus repair. This review describes the most recent advances on the use of hydrogels as platforms for precision meniscus tissue engineering.

Incidence of and Risk Factors for Medial Meniscal Lesions at the Time of ACL Reconstruction: An Analysis of 4697 Knees From the SANTI Study Group Database.

BACKGROUND: Medial meniscal (MM) lesions (MMLs) are a common finding at the time of anterior cruciate ligament reconstruction (ACLR). It is recognized that evaluation of the posteromedial compartment reduces the rate of missed MML diagnoses. PURPOSE: To determine the incidence of MMLs in patients undergoing ACLR, when using a standardized arthroscopic approach that included posteromedial compartment evaluation, as well as to determine how the incidence of MMLs changed with increasing time intervals between injury and surgery, and to investigate what risk factors were associated with their presence. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A retrospective analysis of prospectively collected data was performed. All patients who underwent primary ACLR between January 2013 and March 2023 were considered for study eligibility. The epidemiology was defined by categorizing and reporting the incidence and categorizing the spectrum of MM tear types. Risk factors associated with MMLs were analyzed using a logistic regression model. RESULTS: MMLs were identified in 1851 (39.4%) of 4697 consecutive patients undergoing ACLR. The overall incidence of MMLs was 33.1% for the period of 0 to 3 months, 38.7% for the period of 3 to 12 months, and 59.6% for the period of >12 months. The overall incidence of MMLs increased with longer durations of time between injury and surgery, along with significant increases in complex, bucket-handle, ramp, and/or flap lesions. The largest increase in incidence of MMLs was observed for complex MM tear patterns. Risk factors associated with MMLs included time between injury and surgery >3 months (odds ratio [OR], 1.320; 95% CI, 1.155-1.509; P < .0001) and >12 months (OR, 3.052; 95% CI, 2.553-3.649; P < .0001), male sex (OR, 1.501; 95% CI, 1.304-1.729; P < .0001), body mass index (BMI) ≥25 (OR, 1.193; 95% CI, 1.046-1.362; P = .0088), and lateral meniscal lesion (OR, 1.737; 95% CI, 1.519-1.986; P < .0001). CONCLUSION: Overall, MMLs were identified in 39.4% of 4697 patients undergoing ACLR when posteromedial compartment evaluation was performed in addition to standard anterior viewing. The incidence of MMLs and the complexity of tear types increased significantly with increasing time intervals between the index injury and ACLR. Secondary risk factors associated with an increased incidence of medial meniscal tears include male sex, increased BMI, and lateral meniscal lesions.

Long-term Quality of Life in Patients After ACL Reconstruction With Concomitant Meniscal Injury Treatment: Patient-Reported Outcomes at Minimum 10-Year Follow-up.

Background: Long-term studies of patients after anterior cruciate ligament (ACL) reconstruction with or without concomitant meniscal tear treatment are limited. Purposes: To (1) report postoperative outcomes after anatomic ACL reconstruction with a hamstring autograft, (2) investigate how concomitant treatment of meniscal injury could affect these outcomes, and (3) evaluate the association between quality of life and activity levels at a minimum 10-year follow-up. Study Design: Cohort study; Level of evidence, 3. Methods: Patients treated with a unilateral, anatomic ACL reconstruction between 2005 and 2011 were investigated. The following patient-reported outcome measures (PROMs) were reported for the overall sample as well as a subsample of patients with meniscal injury: International Knee Documentation Committee Subjective Knee Form (IKDC-SKF), Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm knee score, Tegner activity scale, 5-level EQ-5D (EQ-5D-5L), and patient satisfaction. Sex, age, body mass index (BMI), and meniscal injury treatment (meniscectomy vs meniscal repair) were examined as patient-specific risk factors regarding long-term activity and quality of life. Results: Overall, 106 patients, 90 men (85%) and 16 women (15%), were enrolled in the study, with a mean follow-up of 13.2 years. The ACL retear rate was 2.8%. The mean scores were 80.6 ± 16.7 (IKDC-SKF), 87.4 ± 15.0 (KOOS), 90.5 ± 11.5 (Lysholm), 5.6 ± 1.9 (Tegner), and 91.8 ± 14.5 (EQ-5D-5L). The majority (90.6%) of patients considered their knee state satisfactory during follow-up. When compared with patients who underwent meniscal repair, patients who underwent meniscectomy had statistically significantly lower scores on all PROMs except for the Tegner and EQ-5D-5L (P < .05 for all). The mean difference between the 2 groups was ≥7 points on all PROM scores. Patient sex, age, and BMI did not affect PROM scores. There was a statistically significant, strong positive correlation between quality of life and activity. Conclusion: Patients had few or no symptoms and considered their knee state satisfactory 13.2 years after anatomic ACL reconstruction. Patients with concomitant meniscal tears having undergone meniscal repair had improved PROMs compared with those treated with meniscectomy. Finally, participation in activities of daily living and sports was interrelated with quality of life and was not affected by patient age, sex, or BMI.

A deep learning knowledge distillation framework using knee MRI and arthroscopy data for meniscus tear detection.

Purpose: To construct a deep learning knowledge distillation framework exploring the utilization of MRI alone or combing with distilled Arthroscopy information for meniscus tear detection. Methods: A database of 199 paired knee Arthroscopy-MRI exams was used to develop a multimodal teacher network and an MRI-based student network, which used residual neural networks architectures. A knowledge distillation framework comprising the multimodal teacher network T and the monomodal student network S was proposed. We optimized the loss functions of mean squared error (MSE) and cross-entropy (CE) to enable the student network S to learn arthroscopic information from the teacher network T through our deep learning knowledge distillation framework, ultimately resulting in a distilled student network S T. A coronal proton density (PD)-weighted fat-suppressed MRI sequence was used in this study. Fivefold cross-validation was employed, and the accuracy, sensitivity, specificity, F1-score, receiver operating characteristic (ROC) curves and area under the receiver operating characteristic curve (AUC) were used to evaluate the medial and lateral meniscal tears detection performance of the models, including the undistilled student model S, the distilled student model S T and the teacher model T. Results: The AUCs of the undistilled student model S, the distilled student model S T, the teacher model T for medial meniscus (MM) tear detection and lateral meniscus (LM) tear detection are 0.773/0.672, 0.792/0.751 and 0.834/0.746, respectively. The distilled student model S T had higher AUCs than the undistilled model S. After undergoing knowledge distillation processing, the distilled student model demonstrated promising results, with accuracy (0.764/0.734), sensitivity (0.838/0.661), and F1-score (0.680/0.754) for both medial and lateral tear detection better than the undistilled one with accuracy (0.734/0.648), sensitivity (0.733/0.607), and F1-score (0.620/0.673). Conclusion: Through the knowledge distillation framework, the student model S based on MRI benefited from the multimodal teacher model T and achieved an improved meniscus tear detection performance.

A Multi-Task Deep Learning Method for Detection of Meniscal Tears in MRI Data from the Osteoarthritis Initiative Database.

We present a novel and computationally efficient method for the detection of meniscal tears in Magnetic Resonance Imaging (MRI) data. Our method is based on a Convolutional Neural Network (CNN) that operates on complete 3D MRI scans. Our approach detects the presence of meniscal tears in three anatomical sub-regions (anterior horn, body, posterior horn) for both the Medial Meniscus (MM) and the Lateral Meniscus (LM) individually. For optimal performance of our method, we investigate how to preprocess the MRI data and how to train the CNN such that only relevant information within a Region of Interest (RoI) of the data volume is taken into account for meniscal tear detection. We propose meniscal tear detection combined with a bounding box regressor in a multi-task deep learning framework to let the CNN implicitly consider the corresponding RoIs of the menisci. We evaluate the accuracy of our CNN-based meniscal tear detection approach on 2,399 Double Echo Steady-State (DESS) MRI scans from the Osteoarthritis Initiative database. In addition, to show that our method is capable of generalizing to other MRI sequences, we also adapt our model to Intermediate-Weighted Turbo Spin-Echo (IW TSE) MRI scans. To judge the quality of our approaches, Receiver Operating Characteristic (ROC) curves and Area Under the Curve (AUC) values are evaluated for both MRI sequences. For the detection of tears in DESS MRI, our method reaches AUC values of 0.94, 0.93, 0.93 (anterior horn, body, posterior horn) in MM and 0.96, 0.94, 0.91 in LM. For the detection of tears in IW TSE MRI data, our method yields AUC values of 0.84, 0.88, 0.86 in MM and 0.95, 0.91, 0.90 in LM. In conclusion, the presented method achieves high accuracy for detecting meniscal tears in both DESS and IW TSE MRI data. Furthermore, our method can be easily trained and applied to other MRI sequences.

Intra-articular Platelet-Rich Plasma Injections for Treating Knee Pain Associated with Articular Cartilage and Degenerative Meniscal Lesions.

BACKGROUND: Platelet-rich plasma (PRP) is an autologous concentration of platelets that contain a large number of growth factors. These growth factors play a role in the regeneration, repair, and acceleration of the biochemical process, thereby reducing the pain associated with injuries of the articular cartilage and meniscus. AIM: The purpose of this study is to evaluate the effect of the PRP method in the treatment of knee joint cartilage injuries and degenerative meniscus lesions as well as pain relief. MATERIAL AND METHODS: The process of obtaining PRP begins by taking 15 ml of blood from the patient with a special system called Arthrex Double Syringe system. The test tube is centrifuged at 4000 rpm for 5 minutes. From the separated plasma, 5-6 ml PRP is taken and prepared for application. PRP is administered intra-articularly. RESULTS: At the Jan Mitrev Clinic in Skopje in 2018, PRP procedures were performed on 126 patients, 56 (44.4%) of whom were male, and 70 (55.6%) were female. The patients were evaluated by the Tegner Lysholm Knee Scoring Scale (TLKSS) before applying 3 doses of PRP for 7 days as well as 3 and 6 months after the application of PRP. The results showed considerable improvement 3 months after the PRP application, and 6 months after the application the results remained approximately identical. CONCLUSION: The application of PRP in the field of medicine is widely applied, and it will continue to be because the understanding of PRP therapy is increasingly refined. This therapy represents a potential and latest method in short-term pain reduction, but additional studies are needed to prove its long-term effectiveness.

Complex Tears, Extrusion, and Larger Excision Are Prognostic Factors for Worse Outcomes 1 and 2 Years After Arthroscopic Partial Meniscectomy for Degenerative Meniscal Tears: A Secondary Explorative Study of the Surgically Treated Group From the Odense-Oslo Meniscectomy Versus Exercise (OMEX) Trial.

BACKGROUND: Few studies have examined morphological findings from preoperative magnetic resonance imaging (MRI) and arthroscopic findings as prognostic factors for outcomes 1 and 2 years after arthroscopic partial meniscectomy (APM). PURPOSE/HYPOTHESIS: The purpose was to evaluate prognostic factors of preoperative findings from MRI and arthroscopic evaluation on lower extremity performance at 1 year and patient-reported outcomes at 1 to 2 years after APM. The hypothesis was that medial compartment abnormalities would be prognostic for 1- and 2-year functional outcomes. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: This secondary analysis from the OMEX (Odense-Oslo Meniscectomy Versus Exercise) trial included 40 patients treated surgically. Regression analyses with adjustments for age, sex, and body mass index explored associations between MRI findings (tear complexity and extrusion), arthroscopic findings (tear length, cartilage injury, and amount of excised meniscal tissue), and the following: lower extremity performance tests and thigh muscle strength at 1 year and the 5 Knee injury and Osteoarthritis Outcome Score (KOOS) subscales at 1 and 2 years. RESULTS: A complex meniscal tear was a significant and clinically relevant prognostic factor for worse KOOS Symptoms subscores at 2 years (mean, 14.1 points [95% CI, 6.1-22.2]). Meniscal extrusion of at least 11%, 25%, and 20% were significant and clinically relevant prognostic factors for worse KOOS Activities of Daily Living (ADL) subscores at 1 year and worse KOOS Sports and Recreation (Sports/Rec) subscores at 1 and 2 years, respectively. Tear lengths of at least 7.0 mm, 6.7 mm, and 6.5 mm were significant and clinically relevant prognostic factors for better KOOS Symptoms subscores at 1 year and better KOOS Sports/Rec subscores at 1 and 2 years, respectively. A cartilage injury in the medial compartment was a significant and clinically relevant prognostic factor for worse KOOS ADL and Quality of Life (QoL) subscores at 2 years (mean, 10.4 and 19.4 points, respectively [95% CI, 3.4-17.4 and 7.7-31.1, respectively]). More than 20% meniscal tissue excised was a significant and clinically relevant prognostic factor for worse KOOS Pain, Symptoms, ADL, and Sports/Rec subscores at 1 and 2 years (mean, 8.9-41.5 points [95% CI, 2.2-15.5 to 21.0-62.0]) and worse KOOS QoL subscores at 2 years (mean, 25.3 points [95% CI, 13.6-37.0]). CONCLUSION: Complex meniscal tears, larger extrusion, cartilage injuries, and larger meniscal excision were significant and clinically relevant prognostic factors for worse outcomes 1 and 2 years after APM. REGISTRATION: NCT01002794 (ClinicalTrials.gov identifier).

The knee meniscus: management of traumatic tears and degenerative lesions.

Meniscectomy is one of the most popular orthopaedic procedures, but long-term results are not entirely satisfactory and the concept of meniscal preservation has therefore progressed over the years. However, the meniscectomy rate remains too high even though robust scientific publications indicate the value of meniscal repair or non-removal in traumatic tears and non-operative treatment rather than meniscectomy in degenerative meniscal lesionsIn traumatic tears, the first-line choice is repair or non-removal. Longitudinal vertical tears are a proper indication for repair, especially in the red-white or red-red zones. Success rate is high and cartilage preservation has been proven. Non-removal can be discussed for stable asymptomatic lateral meniscal tears in conjunction with anterior cruciate ligament (ACL) reconstruction. Extended indications are now recommended for some specific conditions: horizontal cleavage tears in young athletes, hidden posterior capsulo-meniscal tears in ACL injuries, radial tears and root tears.Degenerative meniscal lesions are very common findings which can be considered as an early stage of osteoarthritis in middle-aged patients. Recent randomised studies found that arthroscopic partial meniscectomy (APM) has no superiority over non-operative treatment. Thus, non-operative treatment should be the first-line choice and APM should be considered in case of failure: three months has been accepted as a threshold in the ESSKA Meniscus Consensus Project presented in 2016. Earlier indications may be proposed in cases with considerable mechanical symptoms.The main message remains: save the meniscus! Cite this article: EFORT Open Rev 2017;2. DOI: 10.1302/2058-5241.2.160056. Originally published online at www.efortopenreviews.org.

Age Differences in the Prevalence of Isolated Medial and Lateral Meniscal Tears in Surgically Treated Patients.

PURPOSE: To compare the prevalence of isolated lateral and medial meniscal tears in different aged populations. METHODS: A five-year retrospective review for meniscal procedures performed on a total of 782 patients. Each chart was reviewed to document the prevalence of medial or lateral meniscal injuries. Inclusion criteria were patients found to have documented evidence of meniscal tear, either lateral or medial, without any concomitant injuries and/or any other procedures performed. Patients excluded from the study were those with concomitant pathologies, such as chondromalacia, malalignment or ligamentous injuries. Patients were classified by age into three groups: < 20 years, 20-30 years and > 30 years old. RESULTS: 68.7% of patients had medial meniscal tears, (average age 37.6 years), 17.1% of these were isolated medial meniscus injuries (average 31.9 years). 31.3% had lateral meniscal injuries (average 27.7 years). Of these, 18.8 % had isolated lateral meniscal injuries (average 22.8 years). All remaining patients had additional diagnoses/procedures. Isolated medial meniscal injuries were more common in older patients as 48 of the 92 isolated medial tears (52.2%) were found in patients > 30 years of age (p <0.001). Isolated lateral meniscal injuries, on the other hand, were more common in younger patients. 29 of the 46 isolated lateral tears (63%) occurred in patients under 20 years (p = 0.002). Only seven (15.2%) isolated lateral tears were shown in patients older than 30 years. CONCLUSION: Isolated lateral meniscal tears are more common in patients < 20 years, and decrease with age, while the prevalence of medial meniscal tears increase with age.

Overexpression of TGF-ß via rAAV-Mediated Gene Transfer Promotes the Healing of Human Meniscal Lesions Ex Vivo on Explanted Menisci.

BACKGROUND: Direct application of therapeutic gene vectors derived from the adeno-associated virus (AAV) might be beneficial to improve the healing of meniscal tears. PURPOSE: To test the ability of recombinant AAV (rAAV) to overexpress the potent transforming growth factor-ß (TGF-ß) in primary cultures of human meniscal fibrochondrocytes, in human meniscal explants, and in experimental human meniscal lesions as a new tool to enhance meniscal repair. STUDY DESIGN: Controlled laboratory study. METHODS: The effects of the candidate treatment on the proliferative and metabolic activities of meniscal cells were monitored in vitro for up to 21 days and in situ in intact and injured human menisci for up to 15 days using biochemical, immunohistochemical, histological, and histomorphometric analyses. RESULTS: Efficient production of TGF-ß via rAAV was achieved in vitro and in situ, both in the intact and injured meniscus. Application of the rAAV TGF-ß vector stimulated the levels of cell proliferation and matrix synthesis (type I collagen) compared with control gene transfer in all systems tested, especially in situ in regions of poor healing capacity and in sites of meniscal injury. No adverse effects of the candidate treatment were observed at the level of osseous differentiation, as tested by immunodetection of type X collagen. Most remarkably, a significant reduction of the amplitude of meniscal tears was noted after TGF-ß treatment, an effect that was associated with increased expression levels of the α-smooth muscle actin contractile marker. CONCLUSION: Overexpression of TGF-ß via rAAV gene transfer is capable of modulating the reparative activities of human meniscal cells, allowing for the healing of meniscal lesions by convenient injection in sites of injury. CLINICAL RELEVANCE: Direct gene-based approaches using rAAV have strong potential to develop new therapeutic options that aim at treating human meniscal defects.

Gene Therapy for Cartilage Repair.

The concept of using gene transfer strategies for cartilage repair originates from the idea of transferring genes encoding therapeutic factors into the repair tissue, resulting in a temporarily and spatially defined delivery of therapeutic molecules to sites of cartilage damage. This review focuses on the potential benefits of using gene therapy approaches for the repair of articular cartilage and meniscal fibrocartilage, including articular cartilage defects resulting from acute trauma, osteochondritis dissecans, osteonecrosis, and osteoarthritis. Possible applications for meniscal repair comprise meniscal lesions, meniscal sutures, and meniscal transplantation. Recent studies in both small and large animal models have demonstrated the applicability of gene-based approaches for cartilage repair. Chondrogenic pathways were stimulated in the repair tissue and in osteoarthritic cartilage using genes for polypeptide growth factors and transcription factors. Although encouraging data have been generated, a successful translation of gene therapy for cartilage repair will require an ongoing combined effort of orthopedic surgeons and of basic scientists.