This case is almost identical to the previous case with a different clinical history. For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. Radial Meniscal Tear: Pearls May be degenerative or traumatic, vertical, millimeters in size, on the inner edge of the lateral meniscus more commonly than the medial meniscus The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. For DSR inquiries or complaints, please reach out to Wes Vaux, Data Privacy Officer, The medial meniscus is more firmly attached to the tibia and capsule than the lateral meniscus, presumably leading to the increased incidence of tears of the medial meniscus [ 8, 11, 12 ]. Root tears are often large radial tears that extend through the entire AP width of the meniscus. bilaterally absent menisci reported by Tolo et al,3 the The intrameniscal ligament where it diverges from the back of the anterior horn of the lateral meniscus is also a common area misinterpreted as a tear. Direct MR arthrography requires intraarticular injection of 20-50 mL of dilute gadolinium contrast prior to imaging which distends the joint capsule and offers a high signal to noise ratio on T1-weighted images with contrast extension into the meniscal substance indicating a recurrent tear or an unhealed repair. Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. Materials and methods . Renew or update your current subscription to Applied Radiology. Exam showed a mild effusion and medial joint line tenderness. The meniscus can separate from the joint capsule or tear through the allograft. immediatly lateral to the anterior horn of lateral meniscus and posterior to the tubercle of anteriro horn of medial meniscus . In cases like this, MR arthrography is quite helpful. Longitudinal medial meniscus tear managed by repair (arrow). When bilateral, they are usually symmetric. On this page: Article: Epidemiology Pathology Radiographic features History and etymology It is important to know the age of the patient when interpreting the MRI. Magnetic resonance imaging (MRI) is the most accurate imaging technique in the diagnosis of meniscal lesions and represents a standard tool in knee evaluation. On the sagittal fat-suppressed T2-weighted image (7B), fluid extends into the tear. Close clinical correlation is advised before recommending surgery based on this finding alone. is much greater than in a discoid lateral meniscus, and the prevalence discoid meniscus, although discoid medial menisci can occur much less Additionally, the postoperative complication of new extensive synovitis is apparent on the axial view (18D). It has been calculated that the lateral meniscus absorbs about 70% of the forces across the lateral compartment of the knee. Indirect MR arthrography is less commonly used and relies on excretion of intravascular gadolinium into the joint through synovial cells after intravenous administration of gadolinium contrast 20-90 minutes prior to the MRI exam. Anterior horn of the lateral meniscus: another potential pitfall in MR imaging of the knee. Considered a feature of knee osteoarthritis. Because there is less pressure on the meniscus there, it is difficult to evaluate the anterior region of the meniscus. Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. Brody J, Lin H, Hulstyn M, Tung G. Lateral Meniscus Root Tear and Meniscus Extrusion with Anterior Cruciate Ligament Tear. Best assessed on T2 weighted sequences. Posterior root repair (Figure 16) is being performed with increasing frequency and has been shown to have better outcomes and decreased risk of osteoarthritis compared to posterior root tears treated non-operatively. Variations in meniscofemoral ligaments at anatomical study and MR imaging. In these cases, thin-section or well-placed axial images confirm that the tear is not a simple radial tear but rather a vertical flap tear (Fig. On the sagittal proton density-weighted image (11A), signal contacts the tibial surface. This injury is biomechanically comparable to a total meniscectomy, leading to compromised hoop stressesresulting in decreased tibiofemoral contact area and increased contact pressures in the involved compartment.These changes are detrimental to the articular cartilage and . The post arthrogram view (13B) reveals gadolinium within the repair site. Choi S, Bae S, Ji S, Chang M. The MRI Findings of Meniscal Root Tear of the Medial Meniscus: Emphasis on Coronal, Sagittal and Axial Images. The patient underwent a successful partial medial meniscectomy and was encouraged to seek low-impact exercise. Arthrofibrosis and synovitis are also relatively common. 3 is least common. meniscus is partial meniscal excision, leaving a 6- to 7-mm peripheral Of those 31 patients who underwent arthroscopic examination, there were only 8 true anterior horn tears (26% true positive rate) and 18 had normal or intact menisci in all zones. ; Lee, S.H. The reported prevalence is 0.06% to 0.3%.25 {"url":"/signup-modal-props.json?lang=us"}, Weerakkody Y, Baba Y, Knipe H, et al. The common insertion of the anterior cruciate ligament (ACL) and the AHLM root may provide a pathway for disease. 2019: Factors associated with bilateral discoid lateral meniscus tear in patients with symptomatic discoid lateral meniscus tear using MRi and X-ray Orthopaedics and Traumatology Surgery and Research: Otsr 105(7): 1389-1394 Become a Gold Supporter and see no third-party ads. Development of the menisci of the human knee If missing on MR images, a posterior root tear is present. Discoid lateral meniscus (DLM) is a common anatomic variant in the knee typically presented in young populations, with a greater incidence in the Asian population than in other populations. However, few studies have directly compared the medial and lateral root tears. Biologic augmentation with application of exogenous fibrin clot or growth factors may be combined with the repair to promote healing. Mucinous degeneration of meniscus can also produce abnormal signal within a meniscus which does not contact an articular surface and should not be mistaken for a tear. A classification system developed by the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine [, Longitudinal-vertical tear. Also, the inferior patella plica inserts on the 2020;49(1):42-49. The main functions attachment of the posterior horn is the Wrisberg meniscofemoral in this case were attributed to an anterior cruciate ligament tear No meniscal tear is seen, but the root attachment was also noted to be . Anterior lateral cysts extended . found that the absence of a line of increased signal through the meniscus extending to the articular surface on proton density and T2-weighted images was a reliable MRI finding for an untorn post-operative meniscus with 100% sensitivity. patella or Hoffas fat pad, and should be fairly easily differentiated Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. The example above demonstrates the importance of baseline MRI comparison when evaluating the postoperative meniscus. Anatomic variability and increased signal change in this area are commonly mistaken for tears. View Mostafa El-Feky's current disclosures, see full revision history and disclosures, Flipped meniscus - anterior horn lateral meniscus, Disproportionate posterior horn sign (meniscal tear). An abnormal shape may indicate a meniscal tear or a partial meniscectomy. Each meniscus attaches to the tibia bone in the back and front via the "meniscal roots." The primary role of the meniscus is to serve as a shock-absorber and protect the underlying articular cartilage and bone. Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. At second look arthroscopy, the posterior horn tear was healed and the anterior horn tear was found to be unstable and treated by partial meniscectomy. (PubMed: 17114506), BakerJC, FriedmanMV, RubinDA (2018) Imaging the postoperative knee meniscus: an evidence-based review. acromioclavicular, sternoclavicular, and temporomandibular joints. . Radiographic knee dimensions in discoid lateral meniscus: Comparison with normal control. Pain is typically medial and activity-related (e.g. Grade 3 is a true meniscus tear and an arthroscope is close to 100 percent accurate in diagnosing this tear. menisci occurs. Description. Magnetic resonance imaging (MRI) and computed tomography (CT) arthrography are both well suited for evaluation of these lesions though somewhat limited by cost and access for MRI and by invasiveness for CT arthrography . My own experience has been similar and I make it a policy not to recommend surgery based on this diagnosis alone without good clinical correlation. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. of the anterior horn of the medial meniscus, an inferior patella plica, Singh K, Helms CA, Jacobs MT, Higgins LD. of the distal femur and proximal tibia, and in the case report of The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). Irrespective of the repair approach or repair devices used, diagnostic criteria for a recurrent tear remains the same fluid signal or contrast extending into the meniscal substance. sagittal magnetic resonance (MR) images. Of the anterior horn tears read on MRI, 85% involved the lateral meniscus anterior horn and about one half were judged to extend into the middle or body of the same meniscus. This arises from the posterior horn of the lateral meniscus and attaches to the lateral aspect of the medial femoral condyle. Medial meniscus bucket handle tears can result in a double PCL sign. Stay up to date with the latest in Practical Medical Imaging and Management with Applied Radiology. morphology but lacks its posterior attachments; ie, the meniscotibial St. Louis County's newspaper of politics and culture This emphasizes the importance of baseline MRI comparison for evaluation of the postoperative meniscus.3. Lateral meniscus bucket handle tears can produce the double anterior horn sign or double ACL sign. 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. Note the symmetrical shape of the lateral meniscus (left) with similar size of the anterior and posterior horns. A meta-analysis of 44 trials. Meniscal root tears are defined as radial tears located within 1 cm from the meniscal attachment or a bony rootavulsion. Shepard and colleagues at UCLA specifically analyzed this by reviewing 947 consecutive MRIs. A 2003 systematic review of the literature, in which 29 publications met strict inclusion criteria, demonstrated pooled weighted sensitivity and specificity of 93.3 % and 88.4 % for the medial meniscus and 79.3 % and 95.7 % for the lateral meniscus, respectively [, Most meniscal tears are visible and best seen on sagittal images. Repair of posterior root tears are being performed with increased frequency over the past several years. posterior fascicles and meniscotibial ligament are absent and a high The location of meniscal tears or signal alterations (anterior/posterior horn or body of the medial/lateral meniscus) and the grade (normal/intra-substance signal abnormality = 0 and tear = 1) were determined on 2D . Anomalous . The meniscus is two crescent-shaped, thick pieces of cartilage that sit in the knee between the tibia and the femur. The patient underwent partial medial meniscectomy and ACL reconstruction. Discoid lateral meniscus and the frequency of meniscal tears. Direct and indirect MR arthrography have been shown to be superior to conventional MRI for detection of recurrent meniscal tears in greater than 25% partial meniscectomies and meniscal repairs; however, conventional MRI is commonly used for initial evaluation of the postoperative meniscus with MR arthrography reserved for equivocal cases. morphology. AJR Am J Roentgenol. Presentation - Middle-older aged individuals, non-traumatic, progressive onset of pain. tear. The posterior cruciate ligament is intact. FSE T2-weighted images, with a slab-like appearance on coronal images. Problems encountered in a discoid medial meniscus are the same as a show cupping of the medial tibial plateau, proximal medial tibial physis frequently. The posterior root of the medial meniscus attaches to the tibia, just anterior and medial to the posterior cruciate ligament (PCL). Unable to process the form. The patient subsequently underwent successful partial medial meniscectomy. Repair techniques include side-to-side repair, stabilization with suture anchors, and the transtibial pull-out technique (figure 4).12. Radiology. Intensity of signal contacting meniscal surface in recurrent tears on MR arthrography compared with that of contrast material. Am J Sports Med 2010; 38:15421548, LaPrade RF, Matheny LM, Moulton SG, James EW, Dean CS. typically into the anterior cruciate ligament. Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. may simulate a peripheral tear (Figure 6).23 The only structure on sagittal images on T1, proton density, and fat-saturated 1. Rao PS, Rao SK, Paul R. Clinical, radiologic, and arthroscopic assessment of discoid lateral meniscus. A meniscus is a crescent-shaped fibrocartilaginous structure that The MRI showed complete ACL tear with displaced bucket handle medial meniscus tear. variants of the meniscus are relatively uncommon and are frequently Am J Sports Med. Objectives: Low-field MRI at 0.55 Tesla (T) with deep learning image reconstruction has recently become commercially available. with mechanical features of clicking and locking. Direct intraarticular injection of 20-50 mL of dilute iodinated contrast is performed with rapid image acquisition using multidetector CT with high spatial resolution and multiplanar reformatted images. Symptomatic anomalous insertion of the medial meniscus. Both horns of the medial meniscus are triangular with sharp points. of the meniscus. This scan showed a radial MMT. No gadolinium extension into the meniscus on fat-suppressed sagittal T1-weighted (9B) post arthrogram view. When interpreting MR images of the knee, it is important to assess for any change from the expected shape of the menisci. 7 Therefore, it is important for the radiologist to be familiar with the appearance of a recurrent tear versus an untorn postoperative meniscus. ligaments and menisci causing severe knee dysplasia in TAR syndrome. The examiner can test the entire posterior horn up to the middle segment of the meniscus using the IR of the tibia followed by an extension. collapse and widening of the medial joint space (Figure 7). After failing conservative management with NSAIDs, PT, and activity modification, he underwent an MRI. medial meniscus, discoid lateral meniscus, including the Wrisberg Figure 7: Meniscofemoral ligament. congenital absence of the cruciate ligaments. If the tear does not show, it is considered a Grade 1 or 2 and is not as serious. 5 In the first instance, tears of the lateral aspect of the anterior horn of the medial meniscus are extremely uncommon and should not be a diagnostic 800-688-2421. It can be divided into five segments: anterior horn, anterior, middle and posterior segments, and posterior horn. Normal menisci. CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. Extension to the anterior cortex of . Note that signal does not contact articular surface, The most common criterion for diagnosing meniscus tear on MRI is an increased signal extending in a line or band to the articular surface. 2006;239(3):805-10. The sagittal proton density-weighted image (2A) demonstrates increased signal intensity at the periphery of the medial meniscus posterior horn (arrow) but no fluid signal on the sagittal T2-weighted image (2B) and no gadolinium extension into this area on the MR arthrogram sagittal fat-suppressed T1-weighted arthrographic image (2C) consistent with a healed repair. These tears are usually degenerative in nature and usually not associated with a discrete injury [. ligament, and the posterior horn may translate or rotate due to Controlling Blood Pressure During Pregnancy Could Lower Dementia Risk, Researchers Address HIV Treatment Gap Among Underserved Population, HHS Announces Reorganization of Office for Civil Rights, FDA Adopts Flu-Like Plan for an Annual COVID Vaccine. MR criteria for discoid lateral menisci are used for discoid medial Vertical flap (oblique, flap, parrots beak) tears are unstable tears and occur in younger patients. Wrisberg variant, the morphology of the meniscus may be normal, but the joint: Morphologic changes and their potential role in childhood Damaged meniscal tissue is removed with arthroscopic instruments including scissors, baskets and mechanical shavers until a solid tissue rim is reached with the meniscal remnant contoured, preserving of as much meniscal tissue as possible. MRI appearance of Wrisberg variant of discoid lateral meniscus. Meniscal surgery is common and requires accurate post-operative imaging interpretation to guide the treatment approach. diminutive (1 mm) with no increased signal to suggest root attachment A It splits into two bands at the PCL, named Humphry(anterior to the PCL) and Wrisberg (posterior to the PCL). The aim of this study was to evaluate diagnostic values involved in conventional magnetic resonance imaging (MRI) features of MM posterior root tears (MMPRTs) and find other MRI-based findings in patients with partial MMPRTs. Type 1 is most common, and type Meniscal tears are common and often associated with knee pain. and ACL tears can be mistaken for AIMM, but carefully tracing the Bilateral hypoplasia of the medial meniscus has also been Pullout fixation of posterior medial meniscus root tears: correlation between meniscus extrusion and midterm clinical results. meniscus are not uncommon; they include an anomalous insertion of the Magn Reson Imaging Clin N Am 2014;22(4): 517555, White LM, Schweitzer ME, Weishaupt D, Kramer J, Davis A, Marks PH. The medial meniscus covers 60% of the medial compartment. 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 High signal close to fluid intensity contacts the tibial surface on the sagittal T2-weighted image (11B) and is equivocal. There is a medial and a lateral meniscus. Medial meniscus posterior horn peripheral longitudinal tear (arrow) seen on the sagittal proton density-weighted image (15A) and managed by repair. Mild irregularities of the meniscal contour may be present, particularly in the first 6-9 months after surgery which tend to smooth out and remodel over time.15 For partial meniscectomies involving less than 25% of the meniscus, conventional MRI is used with the same imaging criteria for evaluating a tear as the native meniscus linear intrasubstance increased signal extending to the articular surface, visualized on 2 images, either consecutively in the same orientation or in the same region in 2 different planes or displaced meniscal fragment (based on the assumption that imaging is spaced at 3 mm intervals). A Study of Retrieved Allografts Used for ACL Surgery, Long-Term Results of Meniscus Allograft Transplantation with Concurrent ACL Reconstruction, Anterior Horn Meniscal Tears — Fact or Fiction, How Triathletes Can Use Cycling Cadence to Maximize Running Performance, Pharmacology Watch: HRT - Position Paper Places Benefits in Question, Clinical Briefs in Primary Care Supplement. Arthroscopy is considered gold standard in the diagnosis of knee ligament injuries, with diagnostic accuracy up to 94% [1], [2]; and can be used therapeutically as well. The MRI also demonstrated moderate degenerative spurring at the lateral joint compartment, a large knee joint effusion with . are reported cases of complete absence of the medial meniscus as The meniscus root plays an essential role in maintaining the circumferential hoop tension and preventing meniscal displacement. : Complications in brief: arthroscopic partial meniscectomy. hypermobility. {"url":"/signup-modal-props.json?lang=us"}, El-Feky M, Flipped meniscus - anterior horn lateral meniscus. Media community. horn of the lateral meniscus, and oblique tear orientation In the present study, the patients analyzed came from the have been the most difficult for imaging planes to visualize same geographical area . both enjoyable and insightful. 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. Conventional MRI is the least invasive modality for evaluation of a meniscal repair but has lower sensitivity, specificity and accuracy than direct or indirect arthrographic MRI. However, the use of MRI arthrography should be considered for post-operative menisci with equivocal findings on conventional MRI as the presence of high gadolinium-like signal within the meniscus would allow for a definitive diagnosis of re-tear. the posterior horn is usually much larger than the anterior horn (the Another finding is the abnormal size or shape of the meniscus, which would indicate damaged surfaces [, To provide a greater degree of accuracy, De Smet advocated the two-slice-touch rule. To call a definite tear, one should see increased signal contacting the articular surface of the menisci on at least two images (sagittal or coronal). 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. meniscal diameter. Sometimes T2 signal in a healed tear may look similar to fluid. This is because most tears occur in the posterior horns [, Whether a torn meniscus is reparable depends on the type or pattern of tear, its location, and the quality of the meniscal tissue. Kim EY, Choi SH, Ahn JH, Kwon JW. varus deformity (Figure 3). the intercondylar notch, most commonly to the mid ACL, and less commonly Concise, to-the-point text covers MRI for the entire musculoskeletal system, presented in a highly templated format. treatment for stable complete or incomplete types of discoid lateral Pinar H, Akseki D, Karaoglan O, et al. The lateral meniscus is one of two fibrocartilaginous menisci of the knee. Fellowship-trained musculoskeletal radiologists read 99% of the MRIs. 22 year-old male with a history of ACL and MCL reconstruction and medial meniscus posterior root repair. At 1 year, 5 of 6 were completely asymptomatic with the remaining patient minimally painful with no suggestion of meniscal symptoms. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. Generally, A displaced longitudinal tear is a "bucket handle" tear. 7.2 Medial and Lateral Menisci Medial meniscus is larger than the lateral meniscus and is more "open" (=less C-like) and less wide. Fat supressed coronal proton density-weighted (19C, D) and sagittal proton density-weighted (19E) images demonstrate postoperative changes from interval posterior horn partial meniscectomy with a thin rim of posterior horn remaining (arrow) and subchondral fractures in the medial femoral condyle and medial tibial plateau (arrowheads) with marked progression of full-thickness chondral loss in the medial compartment and extruded meniscal tissue. menisci develop from this mesenchymal tissue in a site where this tissue Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. Discoid lateral meniscus: Prevalence of peripheral rim instability. Repair techniques include inside-out, outside-in or all-inside approaches. the medial meniscus. Meniscal transplants can fail at the implantation site by avulsion, failure of bone plug incorporation or bone bridge fracture. When it involves the posterior root, medial root tears are easier to diagnose than lateral root tears. of these meniscal variants is the discoid lateral meniscus, and the In the U.S., intraarticular injection of gadolinium-based contrast is off label. Sagittal proton density-weighted image (8A) through the medial meniscus demonstrates signal extending to the tibial surface (arrow). was saddle shaped. Meniscal root tearsare a type of meniscal tearin the knee where the tear extends to either the anterior or posterior meniscal root attachment to the central tibial plateau.