Diagnostic performance is decreased following partial meniscectomy since the standard criteria used to diagnose a meniscus tear cannot be applied to the post-operative meniscus.3,4,5,6 Partial meniscectomy may distort the normal morphology of the meniscus and increased meniscal signal intensity may extend to the articular surface when a portion of the meniscus has been resected, simulating a tear. They are most frequently seen at the posterior horn of the medial meniscus. Knee Surg Sports Traumatol Arthrosc 2011; 19:147157, Gwathmey F.W., Golish S.R., Diduch D.R., et al: Complications in brief: meniscus repair. (1A) Proton density-weighted, (1B) T2-weighted, and (1C) fat-suppressed T1-weighted MR arthrographic sagittal images are provided. 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. immediatly lateral to the anterior horn of lateral meniscus and posterior to the tubercle of anteriro horn of medial meniscus . Symptomatic anomalous insertion of the medial meniscus. Meniscal disorders: Normal, discoid, and cysts. Anterior horn lateral meniscus tear A female asked: Mri: "macerated anterior horn lateral meniscus with inferiorly surfacing tear. 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. The posterior root lies anterior to the posterior cruciate ligament. The avulsed anterior horn of the lateral meniscus is flipped over and situated above the posterior horn. medial meniscus, discoid lateral meniscus, including the Wrisberg The most common location is the anterior horn-body junction of the lateral meniscus and less commonly in the mid posterior horn or root of the medial meniscus. Kim SJ, Choi CH. 6. A tear of the meniscal root means the tear is near where it attaches to the bone, usually far in the back. ligament and meniscal fascicles. Grade II hyperintense horizontal signal of posterior horn of medial meniscus is noted. 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. At the time the article was last revised Yahya Baba had While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. They may not even be apparent with an arthroscopic examination. 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. Normal course and intensity of both cruciate ligaments. Another MRI was later performed due to worsening symptoms, and demonstrated a bucket-handle tear with complete anterior luxation of the posterior horn of the left lateral meniscus (Figs. We will review the common meniscal variants, which 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. An athletic 52-year-old male, who was an avid runner all his adult life, presented with medial pain and a popping sensation in knee. Radial Tear of the Medial Meniscal Root: Reliability and Accuracy of MRI for Diagnosis. Thirty-one of these patients underwent subsequent arthroscopic evaluation to allow clinical correlation. Meniscal root tear. When interpreting MR images of the knee, it is important to assess for any change from the expected shape of the menisci. Meniscal root tears are defined as radial tears located within 1 cm from the meniscal attachment or a bony rootavulsion. Bilateral discoid medial menisci: Case report. Connolly B, Babyn PS, Wright JG, Thorner PS. 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. > 20% ratio of meniscus to tibia on the coronal image; Minimum diameter 14-15 mm on a midcoronal image; 75% 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. Meniscus tears are either degenerative or acute. Source: Shepard MF, et al. of the distal femur and proximal tibia, and in the case report of 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. 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. separate the cavity. mesenchymal mass that differentiates into the tibia, femur, and They often tend to be radial tears extending into the meniscal root. Meniscal tears were found on MRI or arthroscopy in all 28 patients with a lateral cyst overlying the body or posterior horn of the lateral meniscus, whereas a tear was found on MRI or arthroscopy in only 14 (64%) of 22 patients with cysts adjacent to or extending to the lateral meniscus anterior horn (p = 0.006). Figure 8: Medial oblique menisco-meniscal . is much greater than in a discoid lateral meniscus, and the prevalence is in fact reducing the volume of the meniscus and restoring a normal 2006; 187:W565568. Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. 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). {"url":"/signup-modal-props.json?lang=us"}, Weerakkody Y, Baba Y, Knipe H, et al. A tear of the lateral meniscus can occur from a sudden injury, or from chronic wear and overload. 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. Singh K, Helms CA, Jacobs MT, Higgins LD. There was no history of a specific knee injury. 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 Dr. Diduch, Associate Professor, Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA, is Editor of Sports Medicine Reports. medial meniscus, and not be confined to the ACL as seen in an ACL tear. 2013;106(1):91-115. There is no universally accepted system for classifying meniscal tear patterns. Tachibana Y, Yamazaki Y, Ninomiya S. Discoid medial meniscus. Anomalous A tear of the ACL should also, in practice, not be a The camera can visualize the meniscus and other structures within the knee. The most common Magnetic resonance imaging (MRI) is the most accurate imaging technique in the diagnosis of meniscal lesions and represents a standard tool in knee evaluation. 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 Criteria for a recurrent tear after greater than 25% meniscectomy Definite surfacing T2 fluid signal (or high T1 signal isointense to intra-articular gadolinium on MR arthrography) on 2 or more images or displaced meniscal fragment.17 Definite surfacing fluid signal on only one image represents a possible tear. This is a critical differentiation because the latter represents meniscal tears that can be least common is complete congenital absence of the menisci. collapse and widening of the medial joint space (Figure 7). The lateral meniscus is one of two fibrocartilaginous menisci of the knee. Complex or deep radial tears were found in three of five cases of lateral meniscus extrusion and normal root. Discoid lateral meniscus was originally believed to result from an Atypically thick and high location Discoid lateral meniscus in children. Davidson D, Letts M, Glasgow R. Discoid meniscus in children: Treatment and outcome. Because there is less pressure on the meniscus there, it is difficult to evaluate the anterior region of the meniscus. . 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. 2059-2066, Kinsella S.D., and Carey J.L. Absence of the meniscus results in a 200 to 300% increase in contact stresses on the articular surfaces.8The meniscus has a heterogeneous cellular composition with regional and zonal variation, with high proteoglycan content at the thin free edge where compressive forces predominate and low proteoglycan content at the thicker peripheral region where circumferential tensile loads predominate. What causes abnormal mobility in the medial meniscus? The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. Sagittal proton density-weighted image (7A) through the medial meniscus demonstrates increased signal extending to the tibial surface (arrow). When the cruciate It splits into two bands at the PCL, named Humphry(anterior to the PCL) and Wrisberg (posterior to the PCL). Kijowski et al. 9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion. slab-like configuration on sagittal MR images, with > 3 bowties On medial posterior root tears there is often 2: On posterior root radial tears of the lateral meniscus, the appearance may be similar to radial tears in other locations. The MRI revealed a longitudinal tear in the posterior horn of the lateral meniscus. 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. the intercondylar notch, most commonly to the mid ACL, and less commonly tissue only persists at the edges, where differentiation into the 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 . signal fluid cleft interposed between the posterior horn and the capsule The example above demonstrates the importance of baseline MRI comparison when evaluating the postoperative meniscus. They found that 76 (8%) of these indicated a tear of the anterior horn of either the medial or lateral meniscus. However, many clinicians opt to use conventional MRI as the initial postoperative imaging study and reserve MR arthrography for equivocal cases. Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. Arthroscopy for Medial Meniscus Tears The decision to repair or remove the torn portion is made at the time of surgery. of the meniscus. The example above illustrates marked degenerative changes caused by loss of meniscal function. Am J Sports Med 2010; 38:15421548, LaPrade RF, Matheny LM, Moulton SG, James EW, Dean CS. Rohren EM, Kosarek FJ, Helms CA. A 22-years old male presented with injury to right knee in a road traffic accident MRI images shows double posterior horn of lateral meniscus and absent anterior horn in coronal (A: PD; B: STIR; C . 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. 300). A 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. 15 year old patient with prior extensive lateral partial meniscectomy was treated with lateral chondroplasty and lateral meniscal allograft transplant with continued pain and clicking 6 weeks post-operative. AJR Am J Roentgenol 2009;193:515-523. Discoid medial menisci are much less common than discoid lateral menisci,24 and they may be bilateral. 10 A 2003 systematic review of the literature, in which 29 publications met strict inclusion criteria, demonstrated pooled weighted sensitivity and specificity of 93.3 % and 88.4 % for the medial meniscus and 79.3 % and 95.7 % for the lateral meniscus, respectively [, Most meniscal tears are visible and best seen on sagittal images. This is a well-done study with clinical correlation and adequate follow-up. The location of meniscal tears or signal alterations (anterior/posterior horn or body of the medial/lateral meniscus) and the grade (normal/intra-substance signal abnormality = 0 and tear = 1) were determined on 2D . An intact meniscal repair was confirmed at second look arthroscopy. tear. Partial meniscectomy is by far the most common procedure. The patient failed conservative management of aspiration and cortisone injection. We look forward to having you as a long-term member of the Relias instance, tears of the lateral aspect of the anterior horn of the American Board of Orthopaedic Surgery Practice of the Orthopaedic Surgeon: Part-II, certification examination case mix. frequently. Illustration of the medial and lateral menisci. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. meniscus are not uncommon; they include an anomalous insertion of the 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. of the transverse ligament is comparable to the general population.5. They often tend to be radial tears extending into the meniscal root. Meniscal transplants can fail at the implantation site by avulsion, failure of bone plug incorporation or bone bridge fracture. Dickhaut SC, DeLee JC. (middle third), or Type 3 (superior third; intercondylar notch) (Figure ligament will help to exclude these conditions.5 In the first Most studies have shown increased accuracy for direct and indirect MR arthrography compared to conventional MRI for partial meniscectomies of 25% or more.16. The MRI revealed a vertical flap (oblique) tear of the medial meniscus. A meta-analysis of 44 trials. Renew or update your current subscription to Applied Radiology. 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. 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. If a meniscus tear shows up on a MRI, it is considered a Grade 3. Resnick D, Goergen TG, Kaye JJ, et al. What is your diagnosis? ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. 2014; 43:10571064, McCauley TR. It has been calculated that the lateral meniscus absorbs about 70% of the forces across the lateral compartment of the knee. CT arthrography is a recommended alternative for patients who are not MR eligible. Radial tears comprise approximately 15 % of tears in some surgical series [. Kaplan EB. To assess the prevalence of meniscal extrusion and its . joint: Morphologic changes and their potential role in childhood A 23-year-old female presented with a 2-month history of catching and pain in the knee when arising from a squatting position. Choi S, Bae S, Ji S, Chang M. The MRI Findings of Meniscal Root Tear of the Medial Meniscus: Emphasis on Coronal, Sagittal and Axial Images. Anatomic variability and increased signal change in this area are commonly mistaken for tears. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. The fat-suppressed sagittal T1-weighted post arthrogram view (7C) demonstrates gadolinium extending into the meniscal substance. menisci occurs. Am J Sports Med 2017; 45:884891, Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, et al. Anterior horn of the lateral meniscus: another potential pitfall in MR imaging of the knee. acromioclavicular, sternoclavicular, and temporomandibular joints. We hope you found our articles A displaced longitudinal tear is a "bucket handle" tear. Disadvantages include increased cost, increased patient time, potential for adverse reactions to contrast agent compared to conventional MRI and lack of joint distention. And, some tears do not fill with contrast during arthrography. The incidence was calculated based on arthroscopic findings, and the potential secondary signs of meniscal ramp tears were evaluated on MRI. meniscal injury. The common insertion of the anterior cruciate ligament (ACL) and the AHLM root may provide a pathway for disease. Of these 45 patients, there was an average of 3.74 additional pathological conditions noted on the MRI scan, mainly including degenerative arthrosis or patellar chondromalacia to explain the patients continued pain. The anterior root of the lateral meniscus attaches to the tibia, just lateral to the midline and posterior to fibers of the anterior cruciate ligament (ACL). variants of the meniscus are relatively uncommon and are frequently Kim EY, Choi SH, Ahn JH, Kwon JW. The posterior cruciate ligament is intact. It is usually seen near the lateral meniscus central attachment site. that this rare condition is also clinically asymptomatic. Evaluation of postoperative menisci with MR arthrography and routine conventional MRI. Sagittal T2-weighted image (10B) reveals no fluid at the repair site. 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). No gadolinium extension into the meniscus on fat-suppressed sagittal T1-weighted (9B) post arthrogram view. Anterior lateral cysts extended . The patient underwent partial medial meniscectomy and ACL reconstruction. structure on sagittal images on T1, proton density, and fat-saturated (as previously described), meniscal cyst,26 discoid lateral meniscus in the same knee (Figure 9),25 and pathologic medial patella plica.27. These findings are also frequently associated with genu 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. runs from the anterior horn of the medial meniscus to either the ACL or 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. If a horizontal tear involves a long segment of the meniscus, the central fragment may displace centrally from the peripheral portion of the meniscus [, Bucket handle tears (BHT) often cause pain and mechanical symptoms, such as locking, catching, and giving way [. Create a new print or digital subscription to Applied Radiology. meniscus. this may extend to to the mid body." is this a bucket tear? discoid lateral meniscus is a relatively uncommon developmental variant the example shown (Figures 1 and 2), the entire medial meniscus is 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. Lateral meniscus posterior horn peripheral longitudinal tear managed by repair. The trusted source for healthcare information and CONTINUING EDUCATION. Zonal variation is also seen in the density of meniscus cells and their phenotypes with a chondrocytic inner zone and fibroblastic outer zone. 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 posterior fascicles and meniscotibial ligament are absent and a high The meniscus may also become hypertrophic. Both ligaments attach distally to the posterior horn of the lateral meniscus and contribute to posterior drawer stability . be misinterpreted for more significant pathology on MRI. 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 menisci of the knees. trials, alternative billing arrangements or group and site discounts please call Root tears are often large radial tears that extend through the entire AP width of the meniscus. 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. Arthroscopy evaluation found a lateral meniscus peripheral (red-white zone) longitudinal tear. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. 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 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. Description. pivoting). as at no time in development does the meniscus have a discoid This high rate of success, however, may not apply to anterior horn tears, which occur much less commonly than posterior horn and meniscal body tears. 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. Clinical imaging.