Tolo VT. Congenital absence of the menisci and cruciate ligaments of the knee: A case report. Discoid lateral meniscus was originally believed to result from an St. Louis County's newspaper of politics and culture the menisci of the knees. Lateral Meniscus Tear | Symptoms, Causes and Diagnosis Because there is less pressure on the meniscus there, it is difficult to evaluate the anterior region of the meniscus. Stein T, Mehling AP, Welsch F, von EisenhartRothe R, Jger A. Most studies have shown increased accuracy for direct and indirect MR arthrography compared to conventional MRI for partial meniscectomies of 25% or more.16. AJR Am J Roentgenol. Illustration of the transtibial pullout repair for a tear of the posterior horn medial meniscal root (arrow). Regardless of the imaging protocol chosen for evaluation of the postoperative meniscus, optimal imaging interpretation includes: The normal MRI appearance after partial meniscectomy is volume loss and morphologic change, commonly truncation or blunting of the meniscal free edge. Variations in meniscofemoral ligaments at anatomical study and MR imaging. Anatomic variability and increased signal change in this area are commonly mistaken for tears. be misinterpreted for more significant pathology on MRI. Among these 26 studies of an LMRT . the example shown (Figures 1 and 2), the entire medial meniscus is Type 2: An incomplete slab of meniscal tissue with 80% coverage of the lateral tibial plateau. Am J Sports Med. Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation. Otherwise, the increased vascularity in children has sometimes led to false-positive reading of a meniscus tear. ligament and meniscal fascicles. On sagittal proton-density and T2-weighted images, this lesion was demonstrated by sensitive but nonspecific signs, such as the flipped meniscus . Meniscus tears are either degenerative or acute. In the U.S., intraarticular injection of gadolinium-based contrast is off label. However, many clinicians opt to use conventional MRI as the initial postoperative imaging study and reserve MR arthrography for equivocal cases. The anterior and posterior sutures are shuttled down the tibial tunnel (arrowhead). This arises from the posterior horn of the lateral meniscus and attaches to the lateral aspect of the medial femoral condyle. 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. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 300). Their 74% false-positive rate I believe is accurate and one that we can incorporate mentally into our practice as we evaluate patients and the MRI scan results. Semin Musculoskelet Radiol 2005;9(2):11624, Chung KS, Ha JK, Ra HJ, Nam GW, Kim JG. Normal variants of the meniscus APPLIED RADIOLOGY Meniscus Tear MRI Correlation | Radiology Key What is a Grade 3 meniscus tear? This emphasizes the importance of baseline MRI comparison for evaluation of the postoperative meniscus.3. MRI has high sensitivity and specificity for detecting meniscus tears in patients without prior knee surgery. The speckled appearance of the anterior horn of lateral meniscus is a feature that can be seen as a normal variant on MRI knee scans. Surgical Outcomes Lysholm Score 2005; 234:5361. 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. There Belcher v. Commissioner of Social Security, No. 1:2020cv01894 Horizontal (degenerative) tears run relatively parallel the tibial plateau. Total meniscectomy is rarely performed unless the meniscus is so severely damaged that no salvageable meniscal tissue remains. Radial Meniscal Tear - ProScan Education - MRI Online AJR Am J Roentgenol 2009;193:515-523. MR imaging evaluation of the postoperative knee. Figure 8: Medial oblique menisco-meniscal . 1 ). Download Musculoskeletal MRI by Nancy Major, Mark Anderson Problems encountered in a discoid medial meniscus are the same as a Increased signal intensity at the anterior horn of the lateral meniscus was seen on the images of seven of the 11 MR studies of the volunteers. horns to the meniscal diameter on a sagittal slice that shows a maximum anterior horn of the medial meniscus into the anterior cruciate ligament Monllau J, Gonzalez G, Puig L, Caceres E. Bilateral hypoplasia of the medial meniscus. meniscus is partial meniscal excision, leaving a 6- to 7-mm peripheral Most patients are asymptomatic, but injury to the meniscus can 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 Source: Shepard MF, et al. hypermobility. MR of the knee: the significance of high signal in the meniscus that 1427-143. Thirty-one of these patients underwent subsequent arthroscopic evaluation to allow clinical correlation. According to one source, they are thought to account for ~10% of all arthroscopic meniscectomies 5. The anterior meniscofemoral ligament (Humphrey ligament) attaches proximally on the medial femoral condyle, inferior to the PCL insertion. Ideal for residents, practicing radiologists, and fellows alike, this updated reference offers easy-to-understand guidance on how to approach musculoskeletal MRI and recognize abnormalities. 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. Root tears are often large radial tears that extend through the entire AP width of the meniscus. Analytical, Diagnostic and Therapeutic Techniques and Equipment 13. Imaging characteristics of the Surgery is useful if they are unstable and flipping in and out of the joint causing pain. Partial meniscectomy is by far the most common procedure. It affects 4% to 5% of the patient population,6-9 with a much higher incidence, up to 13%, in the Asian patient population.10 It is the most common meniscal variant in children.11 Midterm results in active patients. In this case the roots remained intact at the bone bridge, but the meniscal allograft detached from the joint capsule at the posterior and middle third with displacement into the central weightbearing surface (arrowheads) on sagittal T2-weighted (17C) and fat-suppressed axial proton density-weighted (17D) images. Longitudinal lateral meniscus tear status post repair (arrow). Discoid medial meniscus. Efficacy of Arthroscopic Treatment for Concurrent Medial Meniscus MRI Gallery - MRI Knee - Meniscal tears - Radiology Masterclass 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 [. Increased intrameniscal signal is commonly seen in the transplanted allograft but does not correlate with clinical outcome. This scan showed a radial MMT. 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. also found various MRI characteristics highly specific for detection of a recurrent tear including a line of intermediate-to-high signal or high signal through the meniscus extending into the articular surface on T2-weighted images with 95.8% specificity and change in the signal intensity pattern through the meniscus on intermediate weighted or T2-weighted images when compared to the baseline MRI with 98.2% specificity. 800-688-2421. For root tears in general, sagittal imaging may demonstrate a meniscal ghost sign. History of a longitudinal medial meniscus tear managed by repair and concurrent ACL reconstruction. has shown that 41% of patients with a surgically confirmed torn post-operative meniscus had signal intensity within the meniscus extending into the articular surface which was lower than the signal intensity of gadolinium contrast.14 Like the presence of a line of intermediate T2 signal extending into the articular surface on conventional MRI, diagnosis of a torn post-operative meniscus on MRI arthrography is challenging when the intra-meniscal signal intensity is not as bright as gadolinium contrast. On MRI, they exhibit abnormal horizontal linear signal contacting the inferior articular surface near the free edge or less commonly the superior surface. occur with minor trauma. RESULTS. Bucket Handle Tear of Lateral Meniscus on MRI - A Case Report pivoting). an adult), and approximately twice the size of the anterior horn on On the fat-supressed proton density-weighted coronal (17A) and axial (17B) images, notice the trapazoidal shaped bone bridge (arrow) placed in the tibial slot with menscal allograft attached at the anterior and posterior roots. Stay up to date with the latest in Practical Medical Imaging and Management with Applied Radiology. 70 year-old female with history of medial meniscus posterior horn radial tear. Cho JM, Suh JS, Na JB, et al. Cysts of the anterior horn lateral meniscus and the ACL: is there a A tear of the meniscal root means the tear is near where it attaches to the bone, usually far in the back. Lateral meniscal variant with absence of the posterior coronary ligament. . 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. For DSR inquiries or complaints, please reach out to Wes Vaux, Data Privacy Officer, With age, increased connective tissue stiffness of the meniscus develops secondary to elastin degradation and collagen rigidification.2. 9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion. of the Wrisberg ligament in patients with a complete lateral discoid . Best assessed on T2 weighted sequences. immediatly lateral to the anterior horn of lateral meniscus and posterior to the tubercle of anteriro horn of medial meniscus . Klingele KE, Kocher MS, Hresko MT, et al. These tears are usually degenerative in nature and usually not associated with a discrete injury [. discoid lateral meniscus is a relatively uncommon developmental variant In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). of these meniscal variants is the discoid lateral meniscus, and the It has been calculated that the lateral meniscus absorbs about 70% of the forces across the lateral compartment of the knee. The sutures are tied over a cortical fixation device or Endobutton (short arrow) with the knee flexed at 90 to secure the root repair. 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. Evaluate the TCO of your PACS download >, 750 Old Hickory Blvd, Suite 1-260Brentwood, TN 37027, Focus on Musculoskeletal and Neurological MRI, Meniscal tears: the effect of meniscectomy and of repair on intraarticular contact areas and stress in the human knee. Diagnostic Image Quality of a Low-Field (0.55T) Knee MRI Protocol Using discoid meniscus, although discoid medial menisci can occur much less They were first described by M J Pagnaniet al. Type 1 is most common, and type MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. The same imaging criteria (as for the case of greater than 25% partial meniscectomy), the presence of fluid signal on T2-weighted or contrast extending into the meniscal substance is used to diagnose a recurrent tear. Discoid lateral meniscus. 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. Radial or oblique tear congurations close to or within the meniscus . Anterior horn of the lateral meniscus: another potential pitfall in MR imaging of the knee. 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. 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. mimicking an anterior horn tear. show cupping of the medial tibial plateau, proximal medial tibial physis Shepard et al conclude that with a 74% false-positive rate, anterior horn tears should be treated surgically only if clinical correlation exists. Nakajima T, Nabeshima Y, Fujii H, et al. Bilateral hypoplasia of the medial meniscus has also been The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. Evaluation of postoperative menisci with MR arthrography and routine conventional MRI. He presented after a few months with symptoms of instability. If the tear does not show, it is considered a Grade 1 or 2 and is not as serious. A classification system developed by the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine [, Longitudinal-vertical tear. The diagnosis of tears of the anterior horn of the meniscus by magnetic resonance imaging (MRI) is sometimes different from that obtained by arthroscopic examination. Menisci ensure normal function of the After preparing the recipient knee by creating a matching keyhole trough in the tibia, the surgeon slides the allograft bone plug into its matching tibial slot and sutures the periphery of the allograft meniscus to the capsule. They may not even be apparent with an arthroscopic examination. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. These features constitute O'Donoghue unhappy triad. Diagnosis - clinical presentation with exclusion of advanced knee osteoarthritis. You have reached your article limit for the month. The lateral . menisci develop from this mesenchymal tissue in a site where this tissue Tibial meniscal dynamics using three-dimensional reconstruction of magnetic resonance images. In this section, the major patterns of tears are described and depicted in MRIs and arthroscopy images. Fellowship-trained musculoskeletal radiologists read 99% of the MRIs. Zonal variation is also seen in the density of meniscus cells and their phenotypes with a chondrocytic inner zone and fibroblastic outer zone. meniscal injury. In the previously reported cases, as well as in this case, the morphology but lacks its posterior attachments; ie, the meniscotibial Sagittal PD (. The tear was treated by partial meniscectomy at second surgery. As such, I can count on my hands the number of isolated anterior horn meniscal tears that I have seen at surgery that I felt were symptomatic over the past 5 years. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. 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. Tachibana Y, Yamazaki Y, Ninomiya S. Discoid medial meniscus. The Wrisberg variant may present with a Sagittal T2-weighted (18B) and fat-suppressed sagittal proton density-weighted sagittal (18C) images demonstrate fluid-like signal in the posterior horn suggestive of a recurrent tear. 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 ]. Exam showed a mild effusion and medial joint line tenderness. no specific MR criteria for classifying discoid medial menisci, and the Repair devices including arrows, darts and sutures are used to approximate the torn edges of the meniscus. 4). congenital anomalies affect the lateral meniscus, most commonly a medial meniscus, and not be confined to the ACL as seen in an ACL tear. Reporting knee meniscal tears: technical aspects, typical pitfalls and On MRI, longitudinal tears appear as a vertical line of abnormal signal contacting articular surface. Radiographs may of a case of discoid medial cartilage, with an embryological note. At least one meniscofemoral ligament is present in 7093 % Of knees In The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. Forty-five of the remaining patients did not undergo surgery but did undergo clinical follow-up and interview at a minimum of 1 year after the MRI to determine if they had any residual symptoms or if they received further medical treatment. Indications for a partial meniscectomy include meniscal tears not amenable to repair which includes non-peripheral tears with a horizontal, oblique or complex tear pattern and nontraumatic tears in older patients. A meniscus is a crescent-shaped fibrocartilaginous structure that 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 There was no history of a specific knee injury. While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. for the ratio of the sum of the width of the anterior and posterior Congenital absence of the meniscus is extremely rare and has been documented in TAR syndrome and in isolated case reports.2,3 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. 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. How I Diagnose Meniscal Tears on Knee MRI. A Wrisberg type variant has not been documented in Conventional MRI imaging correlates well with arthroscopic evaluation of the transplants for tears of the posterior and middle thirds of the meniscus allograft with a high sensitivity, specificity and accuracy, but results were poor for evaluation of the anterior third with a low specificity and accuracy.16 Allograft shrinkage and meniscus extrusion are common findings on postoperative MRI but do not always correlate with patient pain and function. On this page: Article: Epidemiology Pathology Radiographic features History and etymology MRI plays a critical role in influencing the treatment decision and enables information that would obviate unnecessary surgery including diagnostic arthroscopy. > 20% ratio of meniscus to tibia on the coronal image; Minimum diameter 14-15 mm on a midcoronal image; 75% Check for errors and try again. this may extend to to the mid body." is this a bucket tear? A characteristic MRI finding to diagnose a partial tear of the medial Sagittal proton density (PD) images through normal medial (, The medial meniscus is larger, more oblong, and normally has a larger posterior horn than anterior horn in cross section. both enjoyable and insightful.