Magnetic resonance imaging (MRI) of both knee joints showed an almost complete absence of the anterior and posterior horns of the medial meniscus, except for the peripheral portion, hypoplastic anterior horns and tears in the posterior horns of the lateral meniscus in both knees (Fig. An algorithm for computing tear meniscus profile meniscus are not uncommon; they include an anomalous insertion of the Am J Sports Med 2010; 38:15421548, LaPrade RF, Matheny LM, Moulton SG, James EW, Dean CS. menisci develop from this mesenchymal tissue in a site where this tissue In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). diagnostic dilemma, as the AIMM band will be seen to extend to the The anterior root of the lateral meniscus attaches to the tibia, just lateral to the midline and posterior to fibers of the anterior cruciate ligament (ACL). However, few studies have directly compared the medial and lateral root tears. Radial Tear of the Medial Meniscal Root: Reliability and Accuracy of MRI for Diagnosis. Disadvantages include increased cost, increased patient time, potential for adverse reactions to contrast agent compared to conventional MRI and lack of joint distention. MR arthrogram fat-suppressed sagittal T1-weighted image (11C) shows no gadolinium in the repair. The post arthrogram view (13B) reveals gadolinium within the repair site. 3. The lateral meniscus is more circular with a shorter radius, covering 70% of the articular surface with the anterior and posterior horns approximately the same size. varus deformity (Figure 3). to the base of the ACL or the intercondylar notch. However, this conjecture and others pre- highest.13,27,34,42 Tear locations, such as the posterior sented in literature are mostly speculative. Because most meniscal tears are not isolated to the red zone, it is understandable that most meniscal surgeries are partial meniscectomies which aim to restore meniscus stability while preserving as much native meniscal tissue as possible, to decrease the risk of osteoarthritis. Still, many clinicians choose to use conventional MRI for initial postoperative imaging which may show displaced meniscal fragments, new tears in different locations or internal derangement not involving the meniscus. 2008;191(1):81-5. 2a, 2b, 2c). normal knee. St. Louis County's newspaper of politics and culture A new longitudinal tear has occurred more centrally in the meniscus (arrowhead) with linear high signal extending to the tibial and femoral surfaces as well as fluid signal and gadolinium contrast in the defect. The meniscus is diffusely vascularized in early life but in adults, only 10-30% of the peripheral meniscus is vascularized, often referred to as the red zone. Meniscus tears, indicated by MRI, are classified in three grades. Discoid medial meniscus. Vertical flap (oblique, flap, parrots beak) tears are unstable tears and occur in younger patients. Diagnosis of meniscal tears on MRI improves when these guidelines are followed to optimize signal-to-noise ratio: high-field-strength magnets are preferable (1.5 T and stronger); a high-resolution surface coil should be used; the field of view should only encompass the necessary structures and routinely be 16 cm or less; image slices should not be too thick (34 mm); and the matrix size should be at least 256192 or higher [, A normal meniscus is low signal on all sequences. It has been calculated that the lateral meniscus absorbs about 70% of the forces across the lateral compartment of the knee. The meniscus root plays an essential role in maintaining the circumferential hoop tension and preventing meniscal displacement. pretzels dipped in sour cream. Magn Reson Imaging Clin N Am 2014;22(4): 517555, White LM, Schweitzer ME, Weishaupt D, Kramer J, Davis A, Marks PH. An abnormal shape may indicate a meniscal tear or a partial meniscectomy. MRI Knee - Sagittal PDFS - Displaced meniscus Part of a torn meniscus can be displaced into another part of the knee joint In this image the anterior part of the meniscus (the anterior horn) is correctly located The posterior horn is displaced such that it is located next to the anterior horn The correct position of the posterior horn is shown Resnick D, Goergen TG, Kaye JJ, et al. Magnetic resonance imaging (MRI), was performed in another facility and, showed normal medial and lateral menisci except for the absence of a medial posterior root insertion both on coronal and on sagittal images. Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. 3 is least common. They maintain a relatively constant distance from the periphery of the meniscus [. Again, this emphasizes the importance of accurate history, prior imaging and operative reports. If the tear does not show, it is considered a Grade 1 or 2 and is not as serious. Anomalous insertion of anterior and posterior horns of medial meniscus There is a medial and a lateral meniscus. Clark CR, Ogden JA. Of these 45 patients, there was an average of 3.74 additional pathological conditions noted on the MRI scan, mainly including degenerative arthrosis or patellar chondromalacia to explain the patients continued pain. (middle third), or Type 3 (superior third; intercondylar notch) (Figure Sagittal proton density-weighted (14A) and coronal T1-weighted (14B) images reveal a recurrent bucket-handle tear through the original repair site with typical findings of a displaced meniscal flap (arrow) into the intercondylar notch. Root tears are often large radial tears that extend through the entire AP width of the meniscus. The camera can visualize the meniscus and other structures within the knee. The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). attachment of the posterior horn is the Wrisberg meniscofemoral . Clin Orthop Relat Res 2012; 470: pp. FSE T2-weighted images, with a slab-like appearance on coronal images. In these cases, MR arthrography may provide additional diagnostic utility. meniscus is partial meniscal excision, leaving a 6- to 7-mm peripheral Meniscus repair is superior to partial meniscectomy in preventing osteoarthritis and facilitating return to athletic activity.11 However, the period of postoperative immobilization and activity restriction associated with meniscus repair is longer than that associated with partial meniscectomy and requires a compliant, motivated patient to be successful. Arthrofibrosis and synovitis are also relatively common. They often tend to be radial tears extending into the meniscal root. For root tears in general, sagittal imaging may demonstrate a meniscal ghost sign. The knee is a complex synovial joint that can be affected by a range of pathologies: ADVERTISEMENT: Supporters see fewer/no ads, Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. At the time the article was created Yuranga Weerakkody had no recorded disclosures. The ideal technique for imaging the postoperative meniscus is a matter of active controversy and depends on the operation performed, surgeon preference and clinical question (concern for recurrent meniscal tear versus articular cartilage). Lateral Meniscus - ProScan Education - MRI Online Become a Gold Supporter and see no third-party ads. Lateral Meniscus Root Tear and Meniscus Extrusion with Anterior In the above case there is no gross chondral defect although the articular cartilage is noticeably thinner compared to the baseline study despite the patients young age. The posterior root of the medial meniscus attaches to the tibia, just anterior and medial to the posterior cruciate ligament (PCL). in 19916. Monllau et al in 1998 proposed adding a fourth type, Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. menisci (Figure 8). Torn lateral meniscus with superomedial and posterior flipped anterior horn. Wrisberg variant, the morphology of the meniscus may be normal, but the Meniscal root tears are a form of radial tear that involves the central attachment of the meniscus (12a). small meniscus is also seen in the wrist joint. The incidence of lateral meniscus posterior root tears was approximately 4 times higher than of medial meniscus posterior root tears in both primary (12.2% vs 3.2%) and revision (20.5% vs 5.6%) ACLRs. Suprapatellar plica noticed, with no related cartilaginous erosions. Midterm results in active patients. Of the 54 participants, 5 had PHLM tears and 49 were normal. Type 2: An incomplete slab of meniscal tissue with 80% coverage of the lateral tibial plateau. Advantages include a less invasive method of introducing intraarticular contrast, the ability to identify areas of hyperemic synovitis or periarticular inflammation based on enhancement and administration can be performed by the technologist. The anterior root of the medial meniscus attaches to the anterior midline of the tibial plateau or sometimes the anterior surface of the tibia just below the plateau. The lateral meniscus is one of two fibrocartilaginous menisci of the knee. They may not even be apparent with an arthroscopic examination. Sagittal proton density-weighted image (5B) through the medial meniscus at age 17 reveals an incomplete tibial surface longitudinal tear (arrow) in a new location and orientation. Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window), Click to share on Google+ (Opens in new window), Posterior Instability and Labral Pathology, Imaging Evaluation of the Painful or Failed Shoulder Arthroplasty, Other Entities: PLRI, HO, Triceps, and Plica, MRI-Arthroscopy Correlations in the Overhead Athlete, Acetabular Fossa, Femoral Fovea, and the Ligamentum Teres. runs from the anterior horn of the medial meniscus to either the ACL or Sagittal T2-weighted (8B) and fat-suppressed coronal T2-weighted (8C) images reveal fluid signal (arrows) extending into the meniscal substance indicating a recurrent tear which was confirmed at second look arthroscopy. This emphasizes the importance of baseline MRI comparison for evaluation of the postoperative meniscus.3. Posterior meniscal root repairs: outcomes of an anatomic transtibial pull-out technique. According to these authors, increased signal to the surface on only one slice should be interpreted as a possible tear. Cases of only one abnormal slice correlated to tears at arthroscopy 55 % of the time for the medial meniscus and 30 % for the lateral [, Accuracy of diagnosing meniscus tear with these criteria has been good. ISAKOS: 2023 Congress in Boston, USA : Abstract Analysis of Risk Volunteerism and Sports Medicine: Where do We Stand? The meniscal repair is intact. Considered a feature of knee osteoarthritis. It can be divided into five segments: anterior horn, anterior, middle and posterior segments, and posterior horn. Objective Parameniscal cysts have a very high association with meniscal tears in all locations except the anterior horn lateral meniscus (AHLM).