800-688-2421. We use cookies to create a better experience. There is no telling how much this error rate will change for radiologists less experienced with MRI. In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). Rohren EM, Kosarek FJ, Helms CA. Ross JA,Tough ICK, English TA. While this test will show a tear up to 90% of the time, it does not always. rim circumferentially, anteriorly, and posteriorly,19 which Stay up to date with the latest in Practical Medical Imaging and Management with Applied Radiology. show cupping of the medial tibial plateau, proximal medial tibial physis 1 ). mesenchymal mass that differentiates into the tibia, femur, and This patient had relief after the initial repair surgery, then had a second injury with recurrent symptoms, which is why the surgeon felt this was a recurrent tear. Repair techniques include side-to-side repair, stabilization with suture anchors, and the transtibial pull-out technique (figure 4).12. 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. Radiographs are usually not diagnostic, but they may show a Anatomic variability and increased signal change in this area are commonly mistaken for tears. in 19916. The shape of the meniscus is formed at the eighth week of . The clinical significance of anterior horn meniscal tears diagnosed on magnetic resonance images. 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. Additionally, the postoperative complication of new extensive synovitis is apparent on the axial view (18D). Complete radial tears, root tears and large partial meniscectomies result in markedly increased contact forces at the articular surface; and in this case, full-thickness chondral loss and subchondral fractures on both sides of the joint. Radiographic knee dimensions in discoid lateral meniscus: Comparison with normal control. A Wrisberg type variant has not been documented in 7.2 Medial and Lateral Menisci Medial meniscus is larger than the lateral meniscus and is more "open" (=less C-like) and less wide. Following partial meniscectomy, the knee is at increased risk for osteoarthritis. mobility, and a giving-way sensation.11, 15, 16 A high percentage of cases present with an associated meniscal tear and peripheral rim instability.9,16,17 Although discoid lateral meniscus is commonly bilateral, symptoms tend to occur on one side.15 It is characterized by an excess of meniscal tissue with a slab-like configuration in the 2 most common forms (Figure 5). A tear of the meniscal root means the tear is near where it attaches to the bone, usually far in the back. 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. There is a medial and a lateral meniscus. When the cruciate Of the 14 athletes, 8 repairs were performed, 5 patients . The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. The lateral meniscus is produced by the varus tension and tibial IR. 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. It is often explained by fibers of the anterior cruciate ligament and the covering synovium . CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. Tears Dr. Diduch, Associate Professor, Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA, is Editor of Sports Medicine Reports. 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. Klingele KE, Kocher MS, Hresko MT, et al. The meniscal repair is intact. discoid meniscus, although discoid medial menisci can occur much less this may extend to to the mid body." is this a bucket tear? They often tend to be radial tears extending into the meniscal root. Methods Eighteen patients who had arthroscopically confirmed partial MMPRTs were included. 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. About KOL ; Learn more about our technology and how more and more universities, research organizations, and companies in all industries are using our data to lower their costs. Discoid lateral meniscus. medial meniscus, and not be confined to the ACL as seen in an ACL tear. 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. 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. The medial meniscus is more tightly anchored than the lateral meniscus, allowing for approximately 5mm of anterior-posterior translation. It is located in the lateral portion of the knee interior of the knee joint. congenital absence of the cruciate ligaments. They divide the meniscus into superior and inferior halves (Fig. posterior horn usually measures 12 mm to 16 mm in the sagittal plane in joint, and they also protect the hyaline cartilage. 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. What is a Lateral Meniscus Tear? Disadvantages include patient discomfort, increased cost, physician time needed for the procedure and radiation exposure during fluoroscopy. the medial meniscus. However, the tear changes plane of orientation over its course. during movement, and less commonly joint-line tenderness, reduced gestation, about the time when the knee joint is fully formed.1 Throughout fetal development, they found that the size of the lateral meniscus is highly variable, unlike the medial meniscus. be misinterpreted for more significant pathology on MRI. AJR American journal of roentgenology. Development of the menisci of the human knee 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 A previous study by De Smet et al. meniscal injury. A . The posterior cruciate ligament is intact. Sagittal proton density-weighted image (8A) through the medial meniscus demonstrates signal extending to the tibial surface (arrow). 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). CT arthrography is a recommended alternative for patients who are not MR eligible. Tolo VT. Congenital absence of the menisci and cruciate ligaments of the knee: A case report. 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). Sagittal proton density-weighted image (6A) through the medial meniscus following partial meniscectomy and debridement of the inferior articular surface shows increased PD signal contacting the inferior articular surface (arrow) but no T2 fluid signal at the surgical site (6B) and no gadolinium signal in the meniscus (6C). problem in practice. Magnetic Resonance Imaging Arthroscopy Orthodontic Extrusion Anterior Cruciate Ligament Reconstruction Arthroscopes Suture Anchors Tissue Culture Techniques Tissue Engineering Injections, Intra-Articular Range of Motion, Articular Arthrography Hardness Tests Orthopedic Procedures Partial meniscectomy is by far the most common procedure. from AIMM. 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. hypermobility. On MR arthrography, (12B), gadolinium extends through the repair site indicating a tear. This case is almost identical to the previous case with a different clinical history. The trusted source for healthcare information and CONTINUING EDUCATION. variants of the meniscus are relatively uncommon and are frequently Variations in meniscofemoral ligaments at anatomical study and MR imaging. Create a new print or digital subscription to Applied Radiology. One important reason for such discrepancies is a failure to understand the transverse geniculate ligament of the knee (TGL). 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. Most horizontal tears extend to the inferior articular surface. Br Med Bull. AJR Am J Roentgenol. During an arthroscopy, we have the choice of either repairing the meniscus tear or removing the torn piece. FSE T2-weighted images, with a slab-like appearance on coronal images. Posterior meniscal root repairs: outcomes of an anatomic transtibial pull-out technique. Following a meniscal repair procedure, the meniscus can be categorized as healed if there is no fluid signal in the repair, partially healed if fluid signal extends into less than 50% of the repair site, or not healed if fluid signal extends into greater than 50% of the repair site. Examination showed lateral joint line tenderness and a positive McMurray sign. acromioclavicular, sternoclavicular, and temporomandibular joints. MRI c spine / head jxn - they can have stenosis of foramen magnum . Conventional MRI is useful for evaluation of posterior root morphology at the tibial tunnel fixation site, meniscal extrusion and articular cartilage. The incidence was calculated based on arthroscopic findings, and the potential secondary signs of meniscal ramp tears were evaluated on MRI. The posterior root of the lateral meniscus (PRLM) attaches along the posterior aspect of the intercondylar eminence of the tibia (Fig. It is important to know the age of the patient when interpreting the MRI. Nakajima T, Nabeshima Y, Fujii H, et al. Figure 7: Meniscofemoral ligament. Pullout fixation of posterior medial meniscus root tears: correlation between meniscus extrusion and midterm clinical results. The medial compartment articular cartilage is preserved, and the meniscal body is not significantly extruded (16D). Fat suppressed sagittal T1-weighted MR arthrogram (5C) demonstrates gadolinium within the tear (arrow). Intensity of signal contacting meniscal surface in recurrent tears on MR arthrography compared with that of contrast material. Midterm results in active patients. MRI showed posterior horn of the medial meniscus (PHMM) horizontal tear with early degenerative changes. Anomalous posterior horn of the medial meniscus include a triangular hypointense The anterior and posterior meniscofemoral ligaments (Humphrey and Wrisberg respectively) are commonly present with one or both found in 93-100% of patients. Objectives: Low-field MRI at 0.55 Tesla (T) with deep learning image reconstruction has recently become commercially available. It has been calculated that the lateral meniscus absorbs about 70% of the forces across the lateral compartment of the knee. normal knee. Discoid lateral meniscus and the frequency of meniscal tears. Kim EY, Choi SH, Ahn JH, Kwon JW. On examination, the patient had medial joint line tenderness with positive McMurray test. Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. Lateral meniscus extrusion was present in six (23%) of 26 LMRTs and five (2.2%) of 231 patients with normal meniscus roots ( P < .001). When it involves the posterior root, medial root tears are easier to diagnose than lateral root tears. seen on standard 4- to 5-mm slices.21 The Wrisberg ligament may also be thick and high in patients with a complete discoid lateral meniscus.22 Other criteria used to diagnose lateral discoid meniscus include the following: In the collapse and widening of the medial joint space (Figure 7). There was no evidence of meniscal extrusion or a meniscal ghost sign (Fig. The patient underwent a successful partial medial meniscectomy and was encouraged to seek low-impact exercise. Meniscal surgery is common and requires accurate post-operative imaging interpretation to guide the treatment approach. Description. occur with minor trauma. posterior fascicles and meniscotibial ligament are absent and a high The post arthrogram view (13B) reveals gadolinium within the repair site. On imaging alone, the radiologist may not be able to distinguish a residual tear (failed repair) from a recurrent tear in the same location. The symptoms Skeletal radiology. According to one source, they are thought to account for ~10% of all arthroscopic meniscectomies 5. Symptomatic anomalous insertion of the medial meniscus. What causes abnormal mobility in the medial meniscus? signal fluid cleft interposed between the posterior horn and the capsule of the Wrisberg ligament in patients with a complete lateral discoid high fibula head and a widened lateral joint space.20 Several varus deformity (Figure 3). On MRI, they exhibit abnormal horizontal linear signal contacting the inferior articular surface near the free edge or less commonly the superior surface. Sagittal T2-weighted image (10B) reveals no fluid at the repair site. Cho JM, Suh JS, Na JB, et al. The main functions Shepard and colleagues at UCLA specifically analyzed this by reviewing 947 consecutive MRIs. 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. Healed peripheral medial meniscus posterior horn repair and new longitudinal tear in a different location. Magn Reson Imaging Clin N Am 2014;22(4): 517555, White LM, Schweitzer ME, Weishaupt D, Kramer J, Davis A, Marks PH. 2012;20(10):2098-103. This emphasizes the importance of baseline MRI comparison for evaluation of the postoperative meniscus.3. 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 ]. A Similarly, the postoperative meniscus is at increased risk for a recurrent tear either at the same or different location due redistribution of forces and increased stress on the articular surface. 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. for the ratio of the sum of the width of the anterior and posterior Torn lateral meniscus with superomedial and posterior flipped anterior horn. Tears of the anterior horn of the medial meniscus, an inferior patella plica, and ACL tears can be mistaken for AIMM, but carefully tracing the ligament will help to exclude these conditions. The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. The example above illustrates marked degenerative changes caused by loss of meniscal function. Grades 1 and 2 are not considered serious. On MRI, longitudinal tears appear as a vertical line of abnormal signal contacting articular surface. asymptomatic, although there is a greater propensity for discoid menisci The avulsed anterior horn of the lateral meniscus is flipped over and situated above the posterior horn. There Comparison of Postoperative Antibiotic Regimens for Complex Appendicitis: Is Two Days as Good as Five Days? Medial meniscus posterior horn peripheral longitudinal tear (arrow) seen on the sagittal proton density-weighted image (15A) and managed by repair. The menisci are C-shaped fibrocartilaginous structures composed of radial and circumferential collagen fibers that have several roles, including joint stabilization, load distribution, articular cartilage protection and joint lubrication. 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. trials, alternative billing arrangements or group and site discounts please call