Discoid medial meniscus. They are most frequently seen at the posterior horn of the medial meniscus. In this case, having the prior MRI exam is useful for showing the location of the initial tear and the new tear in a different location. Nakajima T, Nabeshima Y, Fujii H, et al. 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. The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. 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. This case features the following signs of meniscal tear: absent bow tie appearance of the lateral meniscus ghost meniscus: empty location of the anterior horn of the lateral meniscus Findings indicate an intact meniscus following partial meniscectomy with normal intrameniscal signal. The common insertion of the anterior cruciate ligament (ACL) and the AHLM root may provide a pathway for disease. trials, alternative billing arrangements or group and site discounts please call 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. The most widely used diagnostic modalities to assess the ligament injuries are arthroscopy and Magnetic Resonance Imaging (MRI). diagnostic dilemma, as the AIMM band will be seen to extend to the This case features the following signs of meniscal tear: Case courtesy, Prof. Dr. Khaled Matrawy, Professor of radiology, Alexandria university, Egypt. This emphasizes the importance of baseline MRI comparison for evaluation of the postoperative meniscus.3. The patient had a recent new injury with increased pain. In this section, the major patterns of tears are described and depicted in MRIs and arthroscopy images. Knee Surg Sports Traumatol Arthrosc 2011; 19:147157, Gwathmey F.W., Golish S.R., Diduch D.R., et al: Complications in brief: meniscus repair. Pseudotear Sign of the Anterior Horn of the Meniscus 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. CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. of the AIMM into the ACL is classified as Type 1 (inferior third), Type 2 A characteristic MRI finding to diagnose a partial tear of the medial Stay up to date with the latest in Practical Medical Imaging and Management with Applied Radiology. Disadvantages include patient discomfort, increased cost, physician time needed for the procedure and radiation exposure during fluoroscopy. An intact meniscal repair was confirmed at second look arthroscopy. Am J Sports Med 2017; 45:884891, Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, et al. Special thanks to David Rubin, MD for providing several cases used in this web clinic. typically into the anterior cruciate ligament. 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. MRIs of BHT may have several characteristic appearances including (1) fragment in the notch sign; (2) double anterior horn sign, in which there is an additional meniscal fragment in the anterior joint on top of the native anterior horn; (3) the absent bow tie sign; (4) the double PCL sign, in which the centrally displaced fragment lies just anterior and parallel to the PCL giving the appearance of two PCLs; and (5) the coronal truncation sign, in which the free edge of the meniscal body appears clipped off on coronal images (Fig. an adult), and approximately twice the size of the anterior horn on sagittal magnetic resonance (MR) images. Tachibana Y, Yamazaki Y, Ninomiya S. Discoid medial meniscus. These findings are also frequently associated with genu 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. Sagittal PD (. for the ratio of the sum of the width of the anterior and posterior Diagnosis of recurrent meniscal tears: prospective evaluation of conventional MR imaging, indirect MR arthrography, and direct MR arthrography. Clinical imaging. An intact meniscal repair was confirmed at second look arthroscopy. Objective Parameniscal cysts have a very high association with meniscal tears in all locations except the anterior horn lateral meniscus (AHLM). Lateral Meniscus - ProScan Education - MRI Online Am J Sports Med 2017; 45:4249, ElAttar M, Dhollander A, Verdonk R, Almqvist KF, Verdonk P. Twenty six years of meniscal allograft transplantation: is it still experimental? MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. {"url":"/signup-modal-props.json?lang=us"}, Weerakkody Y, Baba Y, Knipe H, et al. CT arthrography is a recommended alternative for patients who are not MR eligible. Considered a feature of knee osteoarthritis. Close clinical correlation is advised before recommending surgery based on this finding alone. Normal menisci. Type 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 2059-2066, Kinsella S.D., and Carey J.L. The most important clinical concern at the time of MRI imaging is often high-grade articular cartilage loss. Arthroscopy: The Journal of Arthroscopic & Related Surgery. menisci (Figure 8). In these cases, MR arthrography may provide additional diagnostic utility. ligament and meniscal fascicles. occur with minor trauma. These are like large radial tears and can destabilize a large portion of the meniscus. It is located in the lateral portion of the knee interior of the knee joint. 2. Thirty-one of these patients underwent subsequent arthroscopic evaluation to allow clinical correlation. is much greater than in a discoid lateral meniscus, and the prevalence Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. Among these 26 studies of an LMRT . In this case, we can determine that there is a new tear in a different location. continued knee pain after meniscus surgery The ends of the anterior and posterior horns are firmly attached to the tibia at their roots. MR of the knee: the significance of high signal in the meniscus that Sagittal proton density-weighted image (8A) through the medial meniscus demonstrates signal extending to the tibial surface (arrow). Complex or deep radial tears were found in three of five cases of lateral meniscus extrusion and normal root. 7.2 Medial and Lateral Menisci Medial meniscus is larger than the lateral meniscus and is more "open" (=less C-like) and less wide. 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. Anterior horn of the lateral meniscus: another potential pitfall in MR imaging of the knee. Surgery Needed?? : r/MeniscusInjuries 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. This case is almost identical to the previous case with a different clinical history. Methods Eighteen patients who had arthroscopically confirmed partial MMPRTs were included. The trusted source for healthcare information and CONTINUING EDUCATION. Repair techniques include inside-out, outside-in or all-inside approaches. Tears in the red zone have the potential to heal and are more amenable to repair. 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. Variations in meniscofemoral ligaments at anatomical study and MR imaging. The example above illustrates marked degenerative changes caused by loss of meniscal function. Rohren EM, Kosarek FJ, Helms CA. Wrisberg variant, the morphology of the meniscus may be normal, but the signal fluid cleft interposed between the posterior horn and the capsule Knee Examination - Samarpan Physio 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. The most frequent symptom is pain that usually begins with a minor mesenchymal mass that differentiates into the tibia, femur, and Both the healed peripheral tear and the new central tear were proved at second look arthroscopy. Lateral Meniscus Root Tear and Meniscus Extrusion with Anterior (1A) Proton density-weighted, (1B) T2-weighted, and (1C) fat-suppressed T1-weighted MR arthrographic sagittal images are provided. problem in practice. Medial meniscus posterior horn peripheral longitudinal tear (arrow) seen on the sagittal proton density-weighted image (15A) and managed by repair. A meniscus is a crescent-shaped fibrocartilaginous structure that frequently. Radiology. pretzels dipped in sour cream. PDF The Menisci on MRI Pearls and Pitfalls or the Radiology Registrar Create a new print or digital subscription to Applied Radiology. to the base of the ACL or the intercondylar notch. does not normally occur.13. Shepard et al have done a nice job of telling us just how frequently this mistake can be made by fellowship trained musculoskeletal radiologists. PDF Coronal extrusion of the lateral meniscus does not increase after The Wrisberg variant may present with a A detached posterior root is functionally equivalent to a total meniscectomy with loss of its ability to withstand hoop stress. However, few studies have directly compared the medial and lateral root tears. structure on sagittal images on T1, proton density, and fat-saturated For root tears in general, sagittal imaging may demonstrate a meniscal ghost sign. Pre-operative fat supressed coronal proton density-weighted image (19A) demonstates a posterior root radial tear (arrow). Cho JM, Suh JS, Na JB, et al. Interested in Group Sales? 3: The Wrisberg variant, where the meniscus may have a normal Cysts of the anterior horn lateral meniscus and the ACL: is there a Bilateral discoid medial menisci: Case report. Flipped meniscus - anterior horn lateral meniscus | Radiology Case Connolly B, Babyn PS, Wright JG, Thorner PS. Learn more. Materials and methods . medial meniscus, and not be confined to the ACL as seen in an ACL tear. partly divides a joint cavity, unlike articular discs, which completely congenital anomalies affect the lateral meniscus, most commonly a medial meniscus, discoid lateral meniscus, including the Wrisberg A recurrent tear was proved at second look arthroscopy. It is important to know the age of the patient when interpreting the MRI. 2012;20(10):2098-103. RESULTS. The superior, middle and inferior geniculate arteries are the main vascular supply to the menisci. On imaging alone, the radiologist may not be able to distinguish a residual tear (failed repair) from a recurrent tear in the same location. How I Diagnose Meniscal Tears on Knee MRI. Check for errors and try again. Lee, J.W. A tear of the lateral meniscus can occur from a sudden injury, or from chronic wear and overload. In this case, the patient never obtained relief from the initial surgery, and the surgeon felt this was a residual tear (failed repair) rather than a recurrent tear. Root tears are often large radial tears that extend through the entire AP width of the meniscus. PRIME PubMed | Posterior horn lateral meniscal tears simulating (PDF) Sensitivity and Specificity of MRI in Diagnosing Concomitant CT arthrography may be used to evaluate the postoperative meniscus when MRI is contraindicated. incomplete breakdown of the central meniscus, but this is now disputed, The patient underwent an all-inside lateral meniscus repair. of the meniscus. With age, increased connective tissue stiffness of the meniscus develops secondary to elastin degradation and collagen rigidification.2. Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. They were first described by M J Pagnaniet al. Mechanical rasping or trephination of the torn meniscus ends and parameniscal synovium is used to promote bleeding and vascular healing. congenital absence of the cruciate ligaments. The anterior and posterior meniscofemoral ligaments (Humphrey and Wrisberg respectively) are commonly present with one or both found in 93-100% of patients.9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion.10. 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. 2006; 187:W565568. ligaments are absent, most commonly the anterior cruciate ligament (ACL) Anterior horn of the lateral meniscus: another potential - PubMed The discoid lateral-meniscus syndrome. Bucket Handle Tear of Lateral Meniscus on MRI - A Case Report MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. slab-like configuration on sagittal MR images, with > 3 bowties medial meniscus are extremely uncommon and should not be a diagnostic Laundre BJ, Collins MS, Bond JR, Dahm DL, Stuart MJ, Mandrekar JN: MRI accuracy for tears of the posterior horn of the lateral meniscus in patients with acute anterior cruciate ligament injury and the clinical relevance of missed tears. Generally, Suprapatellar plica noticed, with no related cartilaginous erosions. Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. Indications for meniscal repair typically include posttraumatic peripheral (red zone) longitudinal tears located near the joint capsule, ideally in younger patients (less than 40). 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 . Of the 54 participants, 5 had PHLM tears and 49 were normal. 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. 6. The anterior horn inserts on the tibia and continues laterally to the anterior horn of the lateral meniscus via the transverse intermeniscal ligament. When it involves the posterior root, medial root tears are easier to diagnose than lateral root tears. Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. Radial or oblique tear congurations close to or within the meniscus . At 1 year, 5 of 6 were completely asymptomatic with the remaining patient minimally painful with no suggestion of meniscal symptoms. 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). Clin Orthop Relat Res 2012; 470: pp. 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. Lateral meniscus extrusion was present in six (23%) of 26 LMRTs and five (2.2%) of 231 patients with normal meniscus roots ( P < .001). Of these patients treated nonoperatively, 6 had a diagnosis of an isolated anterior horn tear on MRI. noted to be diminutive, with the posterior horn measuring 7 mm to 8 mm. Note the symmetrical shape of the lateral meniscus (left) with similar size of the anterior and posterior horns. Description. The reported prevalence is 0.06% to 0.3%.25 The knee is a complex synovial joint that can be affected by a range of pathologies: ADVERTISEMENT: Supporters see fewer/no ads, Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. What is a Lateral Meniscus Tear? 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. Normal the rare ring-shaped meniscus, to the classification. Most lateral meniscal tears are due to twisting or turning activities or falls. 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). Unable to process the form. The avulsed anterior horn of the lateral meniscus is flipped over and situated above the posterior horn.

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