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. . 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. 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. Kaplan EB. 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. 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 . 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 Knee Surg Sports Traumatol Arthrosc. 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 The sensitivity of mri in detecting meniscal tears is generally good, ranging from 70-98%, with specificity in the same range in many studies. 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. 2012;20(10):2098-103. Most horizontal tears extend to the inferior articular surface. 7 Therefore, it is important for the radiologist to be familiar with the appearance of a recurrent tear versus an untorn postoperative meniscus. AJR American journal of roentgenology. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. Anterior horn of the lateral meniscus: another potential pitfall in MR imaging of the knee. A meta-analysis of 44 trials. posterior horn of the medial meniscus include a triangular hypointense As a result, the accuracy rate of diagnosis by MRI is 83.3%. The patient had a recent new injury with increased pain. CT arthrography is a recommended alternative for patients who are not MR eligible. Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. At the time the article was last revised Yahya Baba had It is possible that there could have been some tears missed at arthroscopy that were on the undersurface of the anterior horn, an area which is extremely difficultif not impossibleto visualize. Imaging characteristics of the A previous study by De Smet et al. Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. Methods Eighteen patients who had arthroscopically confirmed partial MMPRTs were included. What causes abnormal mobility in the medial meniscus? Schwenke M, Singh M, Chow B Anterior Cruciate Ligament and Meniscal Tears: A Multi-modality Review. Studies on meniscus root tears have investigated the relationship of osteoarthritis and an anterior cruciate ligament tear. No gadolinium extension into the meniscus on fat-suppressed sagittal T1-weighted (9B) post arthrogram view. Objective Parameniscal cysts have a very high association with meniscal tears in all locations except the anterior horn lateral meniscus (AHLM). 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. Clinical History: An 18 year-old male with a history of a posterior horn medial meniscus peripheral longitudinal tear treated with meniscal repair at age 16 presents for MR imaging. 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 ]. In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). On imaging alone, the radiologist may not be able to distinguish a residual tear (failed repair) from a recurrent tear in the same location. 1). 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. medial meniscus, discoid lateral meniscus, including the Wrisberg Relevant clinical history, prior imaging and use of operative reports will significantly improve accuracy of post-operative interpretations. variant, and discoid medial meniscus. medial meniscus are extremely uncommon and should not be a diagnostic Ross JA,Tough ICK, English TA. Discoid lateral meniscus: Prevalence of peripheral rim instability. 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. While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. The sagittal proton density-weighted image (13A) demonstrates linear high signal extending to the femoral and tibial surfaces (arrow). Is sport activity possible after arthroscopic meniscal allograft transplantation? discoid lateral meniscus is a relatively uncommon developmental variant ligaments and menisci causing severe knee dysplasia in TAR syndrome. The ends of the anterior and posterior horns are firmly attached to the tibia at their roots. There is no telling how much this error rate will change for radiologists less experienced with MRI. 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. 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 ]. Tears in the red zone have the potential to heal and are more amenable to repair. Magnetic resonance imaging (MRI) is the most accurate imaging technique in the diagnosis of meniscal lesions and represents a standard tool in knee evaluation. Kim EY, Choi SH, Ahn JH, Kwon JW. AJR Am J Roentgenol. An abnormal shape may indicate a meniscal tear or a partial meniscectomy. Following meniscal allograft transplantation (Figure 17), complications occur in up to 21% of procedures, including allograft failure and progressive cartilage loss.19 Repeat operations occur in up to 35% of patients, 12% requiring conversion to total knee arthroplasty. The meniscus can separate from the joint capsule or tear through the allograft. 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. acromioclavicular, sternoclavicular, and temporomandibular joints. 2005; 234:5361. no specific MR criteria for classifying discoid medial menisci, and the Normal course and intensity of both cruciate ligaments. diminutive (1 mm) with no increased signal to suggest root attachment The most common Arthroscopy evaluation found a lateral meniscus peripheral (red-white zone) longitudinal tear. Dr. Diduch, Associate Professor, Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA, is Editor of Sports Medicine Reports. It is usually seen near the lateral meniscus central attachment site. Lee S, Jee W, Kim J. The discoid lateral-meniscus syndrome. A tear of the meniscal root means the tear is near where it attaches to the bone, usually far in the back. Monllau et al in 1998 proposed adding a fourth type, Anatomic variability and increased signal change in this area are commonly mistaken for tears. Anatomic variability and increased signal change in this area are commonly mistaken for tears. This has also been described as grade 2 signal [, Sagittal fat-suppressed T2 image of a 14-year-old patient showing a grade 2 signal in the posterior horn of the medial meniscus (PHMM). The posterior horn is always larger than the anterior horn. Suprapatellar plica noticed, with no related cartilaginous erosions. Sagittal T2-weighted image (10B) reveals no fluid at the repair site. least common is complete congenital absence of the menisci. The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. Sagittal proton density-weighted image (8A) through the medial meniscus demonstrates signal extending to the tibial surface (arrow). The most frequent symptom is pain that usually begins with a minor The medial meniscus is more tightly anchored than the lateral meniscus, allowing for approximately 5mm of anterior-posterior translation. The meniscus may also become hypertrophic. Radial tears comprise approximately 15 % of tears in some surgical series [. The MRI sign of a radial tear is a linear, vertical cleft of abnormal high signal at the free edge (Fig. 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. 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. 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. described in thrombocytopenia absent radius syndrome (TAR syndrome).2,3 Bilateral hypoplasia of the medial meniscus has also been reported.4. is affected. What is a Grade 3 meniscus tear? 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. The insertion site 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. Heron, D, Bonnard C, Moraine C,Toutain A. Agenesis of cruciate Youderian A, Chmell S, Stull MA. Posteroinferior displacement of the meniscal tissue (arrowheads) is also diagnostic of recurrent tear. Case 9: posterior root of medial meniscus, View Yuranga Weerakkody's current disclosures, see full revision history and disclosures, anterior cruciate ligament avulsion fracture, posterior cruciate ligament avulsion fracture, Ahlback classification system in assessing osteoarthritis of the knee joint, Kellgren and Lawrence system for classification of osteoarthritis, anterior cruciate ligament mucoid degeneration, MRI grading system for meniscal signal intensity, shortening or absence of the root on sagittal images, vertical fluid cleft on coronal fluid-sensitive (T2) images. Davidson D, Letts M, Glasgow R. Discoid meniscus in children: Treatment and outcome. The avulsed anterior horn of the lateral meniscus is flipped over and situated above the posterior horn. They found that 76 (8%) of these indicated a tear of the anterior horn of either the medial or lateral meniscus. AJR Am J Roentgenol. 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). Acute partial interstitial to near complete anterior cruciate ligament tear is noted at its posterior end with femoral deep lateral sulcus sign. the medial meniscus. Discoid lateral meniscus in children. Kijowski et al. Radiology. Pre-operative fat supressed coronal proton density-weighted image (19A) demonstates a posterior root radial tear (arrow). In this section, the major patterns of tears are described and depicted in MRIs and arthroscopy images. 36 year old male with history of meniscus surgery 7 years ago. Normal Because this is a relatively new procedure, few studies have been dedicated to MRI evaluation of postoperative root repair. 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. of these meniscal variants is the discoid lateral meniscus, and the problem in practice. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. Discoid medial menisci are much less common than discoid lateral menisci,24 and they may be bilateral. The congenitally absent meniscus appears to influence the development . On the sagittal fat-suppressed T2-weighted image (7B), fluid extends into the tear. the intercondylar notch, most commonly to the mid ACL, and less commonly 2006;239(3):805-10. Report Shepard and colleagues at UCLA specifically analyzed this by reviewing 947 consecutive MRIs. Root tears are often large radial tears that extend through the entire AP width of the meniscus. The ligament of Humphrey inserted on average 0.9 consecutive images lateral to the PCL without an PHLM tear and 4.7 with an PHLM tear; the ligament of Wrisberg inserted on average 3.0 consecutive images without an PHLM tear and 4.5 with an PHLM tear .