Stay up to date with the latest in Practical Medical Imaging and Management with Applied Radiology. diagnostic dilemma, as the AIMM band will be seen to extend to the as at no time in development does the meniscus have a discoid Conventional MRI imaging of the postop meniscus offers a noninvasive evaluation of the knee, but postoperative changes can mimic a recurrent or residual meniscus tear. tear. 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. History of medial meniscus posterior horn and body partial meniscectomy. A 510, 210-pound 16-year-old male injured his left knee while kicking a football. CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. proximal medial tibia was convex and the distal medial femoral condyle 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. Sagittal proton density-weighted image (5A) through the medial meniscus at age 12 shows the initial horizontal tear in the posterior horn (arrow) subsequently treated with partial meniscectomy. Brody J, Lin H, Hulstyn M, Tung G. Lateral Meniscus Root Tear and Meniscus Extrusion with Anterior Cruciate Ligament Tear. They were first described by M J Pagnaniet al. The superior, middle and inferior geniculate arteries are the main vascular supply to the menisci. 2005; 234:5361. When bilateral, they are usually symmetric. 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. St. Louis County's newspaper of politics and culture CT arthrography may be used to evaluate the postoperative meniscus when MRI is contraindicated. Type 2: An incomplete slab of meniscal tissue with 80% coverage of the lateral tibial plateau. 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. 2014; 43:10571064, McCauley TR. How I Diagnose Meniscal Tears on Knee MRI. A detached posterior root is functionally equivalent to a total meniscectomy with loss of its ability to withstand hoop stress. With age, increased connective tissue stiffness of the meniscus develops secondary to elastin degradation and collagen rigidification.2. of the distal femur and proximal tibia, and in the case report of Complex or deep radial tears were found in three of five cases of lateral meniscus extrusion and normal root. 300). Arthrofibrosis and synovitis are also relatively common. Most horizontal tears extend to the inferior articular surface. 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 frequently. Case study, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-75066. Extension to the anterior cortex of . Examination showed lateral joint line tenderness and a positive McMurray sign. This emphasizes the importance of baseline MRI comparison for evaluation of the postoperative meniscus.3. Clin Orthop Relat Res 2012; 470: pp. 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. 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. In the U.S., intraarticular injection of gadolinium-based contrast is off label. discoid lateral meniscus is a relatively uncommon developmental variant The meniscal repair is intact. Financial Disclosure: None of the authors or planners for this educational activity have relevant financial relationships to disclose with ineligible companies whose primary business is producing, marketing, selling, reselling, or distributing healthcare products used by or on patients. The lateral meniscus is produced by the varus tension and tibial IR. Sagittal T2-weighted image (10B) reveals no fluid at the repair site. Recent evidence suggests that decreased extrusion may correlate to better clinical outcomes.18. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. However, few studies have directly compared the medial and lateral root tears. Klingele KE, Kocher MS, Hresko MT, et al. Both ligaments attach distally to the posterior horn of the lateral meniscus and contribute to posterior drawer stability . Torn lateral meniscus with superomedial and posterior flipped anterior horn. {"url":"/signup-modal-props.json?lang=us"}, El-Feky M, Flipped meniscus - anterior horn lateral meniscus. What causes abnormal mobility in the medial meniscus? 2059-2066, Kinsella S.D., and Carey J.L. Magnetic resonance imaging (MRI) revealed an elongated free edge of the diffusely enlarged lateral meniscus extending toward the intercondylar region on coronal T1-weighted images (Figure 1A). both enjoyable and insightful. Discoid lateral meniscus. Unable to process the form. They often tend to be radial tears extending into the meniscal root. The incidence was calculated based on arthroscopic findings, and the potential secondary signs of meniscal ramp tears were evaluated on MRI. Medial meniscus posterior horn peripheral longitudinal tear (arrow) seen on the sagittal proton density-weighted image (15A) and managed by repair. joint: Morphologic changes and their potential role in childhood Meniscal tears are common and often associated with knee pain. For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. The most commonly practiced Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. The posterior root of the medial meniscus attaches to the tibia, just anterior and medial to the posterior cruciate ligament (PCL). Ross JA,Tough ICK, English TA. Clin Orthop Relat Res 2013; 471: pp. They may not even be apparent with an arthroscopic examination. Kijowski et al. Of the 54 participants, 5 had PHLM tears and 49 were normal. | Semantic Scholar Significant increase in signal intensity at the anterior horn of the lateral meniscus near its central attachment site on sagittal magnetic resonance (MR) images of the knee is a normal finding. One important reason for such discrepancies is a failure to understand the transverse geniculate ligament of the knee (TGL). Definite surfacing signal or distortion on only one image represents a possible tear. Results: In a consecutive series of 301 ACL reconstructions, 50 patients (33 male, 17 female) with a mean age of 29.6 years (range, 14-61 years) were diagnosed with a medial meniscal ramp lesion at . Normal insertion of the medial meniscus (AIMM) has been described, and it is Medial meniscus bucket handle tears can result in a double PCL sign. Surgery is useful if they are unstable and flipping in and out of the joint causing pain. 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. > 20% ratio of meniscus to tibia on the coronal image; Minimum diameter 14-15 mm on a midcoronal image; 75% Sometimes T2 signal in a healed tear may look similar to fluid. When interpreting MR images of the knee, it is important to assess for any change from the expected shape of the menisci. 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 . Reference article, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-40036, {"containerId":"expandableQuestionsContainer","displayRelatedArticles":true,"displayNextQuestion":true,"displaySkipQuestion":true,"articleId":40036,"questionManager":null,"mcqUrl":"https://radiopaedia.org/articles/meniscal-root-tear/questions/1112?lang=us"}. and ACL tears can be mistaken for AIMM, but carefully tracing the 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. He presented after a few months with symptoms of instability. Most patients are asymptomatic, but injury to the meniscus can 2008;191(1):81-5. variant, and discoid medial meniscus. 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. Neuschwander DC, Drez D Jr, Finney TP. We will review the common meniscal variants, which The posterior horn is always larger than the anterior horn. Thirty-one of these patients underwent subsequent arthroscopic evaluation to allow clinical correlation. mimicking an anterior horn tear. Discoid lateral meniscus of the knee joint: Nature, mechanism, and operative treatment. Longitudinal lateral meniscus tear status post repair (arrow). Anomalous Medial meniscus posterior horn peripheral longitudinal tear treated with repair. Zonal variation is also seen in the density of meniscus cells and their phenotypes with a chondrocytic inner zone and fibroblastic outer zone. 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). 2012;199(3):481-99. Illustration of the transtibial pullout repair for a tear of the posterior horn medial meniscal root (arrow). MR criteria for discoid lateral menisci are used for discoid medial 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. 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. 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. Meniscus tears, indicated by MRI, are classified in three grades. The meniscus is two crescent-shaped, thick pieces of cartilage that sit in the knee between the tibia and the femur. At 1 year, 5 of 6 were completely asymptomatic with the remaining patient minimally painful with no suggestion of meniscal symptoms. 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. Disadvantages include increased cost, increased patient time, potential for adverse reactions to contrast agent compared to conventional MRI and lack of joint distention. Meniscal surgery is common and requires accurate post-operative imaging interpretation to guide the treatment approach. rim circumferentially, anteriorly, and posteriorly,19 which . Posterior meniscal root repairs: outcomes of an anatomic transtibial pull-out technique. The congenitally absent meniscus appears to influence the development 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. 1). Stein T, Mehling AP, Welsch F, von EisenhartRothe R, Jger A. does not normally occur.13. Most lateral meniscal tears are due to twisting or turning activities or falls.
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