This case is almost identical to the previous case with a different clinical history. 9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion. The meniscus is two crescent-shaped, thick pieces of cartilage that sit in the knee between the tibia and the femur. Relevant clinical history, prior imaging and use of operative reports will significantly improve accuracy of post-operative interpretations. 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). Check for errors and try again. Normal snapping knee due to hypermobility. 2006; 187:W565568. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. bilaterally absent menisci reported by Tolo et al,3 the 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 menisci of the knees. Figure 8: Medial oblique menisco-meniscal . Radiographic knee dimensions in discoid lateral meniscus: Comparison with normal control. Become a Gold Supporter and see no third-party ads. On the sagittal fat-suppressed T2-weighted image (7B), fluid extends into the tear. Intensity of signal contacting meniscal surface in recurrent tears on MR arthrography compared with that of contrast material. both enjoyable and insightful. 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). 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. Ross JA,Tough ICK, English TA. Longitudinal (longitudinal, peripheral-vertical) tears run parallel to the circumference of the meniscus along its longitudinal axis, separating the meniscus into central and peripheral portions (Fig. Of the 54 participants, 5 had PHLM tears and 49 were normal. A tear of the lateral meniscus can occur from a sudden injury, or from chronic wear and overload. Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. typically into the anterior cruciate ligament. Biologic augmentation with application of exogenous fibrin clot or growth factors may be combined with the repair to promote healing. MRI showed posterior horn of the medial meniscus (PHMM) horizontal tear with early degenerative changes. Vertical flap (oblique, flap, parrots beak) tears are unstable tears and occur in younger patients. 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. Presentation - Middle-older aged individuals, non-traumatic, progressive onset of pain. 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. Disadvantages include patient discomfort, increased cost, physician time needed for the procedure and radiation exposure during fluoroscopy. RESULTS. An intact meniscal repair was confirmed at second look arthroscopy. Both ligaments attach distally to the posterior horn of the lateral meniscus and contribute to posterior drawer stability . 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. We will review the common meniscal variants, which Pain is typically medial and activity-related (e.g. Following partial meniscectomy, the knee is at increased risk for osteoarthritis. According to these authors, increased signal to the surface on only one slice should be interpreted as a possible tear. Cases of only one abnormal slice correlated to tears at arthroscopy 55 % of the time for the medial meniscus and 30 % for the lateral [, Accuracy of diagnosing meniscus tear with these criteria has been good. 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. Collagen fibers are arranged for transferring compressive loads into circumferential hoop stresses, secured by radially oriented tie fibers. Pagnani M, Cooper D, Warren R. Extrusion of the Medial Meniscus. Magnetic resonance imaging of the postoperative meniscus: resection, repair, and replacement. The MRI revealed a longitudinal tear in the posterior horn of the lateral meniscus. Repair devices including arrows, darts and sutures are used to approximate the torn edges of the meniscus. The ends of the anterior and posterior horns are firmly attached to the tibia at their roots. asymptomatic, although there is a greater propensity for discoid menisci also found various MRI characteristics highly specific for detection of a recurrent tear including a line of intermediate-to-high signal or high signal through the meniscus extending into the articular surface on T2-weighted images with 95.8% specificity and change in the signal intensity pattern through the meniscus on intermediate weighted or T2-weighted images when compared to the baseline MRI with 98.2% specificity. Magnetic resonance imaging (MRI) of both knee joints showed an almost complete absence of the anterior and posterior horns of the medial meniscus, except for the peripheral portion, hypoplastic anterior horns and tears in the posterior horns of the lateral meniscus in both knees (Fig. Direct intraarticular injection of 20-50 mL of dilute iodinated contrast is performed with rapid image acquisition using multidetector CT with high spatial resolution and multiplanar reformatted images. Copy. Objective Parameniscal cysts have a very high association with meniscal tears in all locations except the anterior horn lateral meniscus (AHLM). 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. Meniscal root tears are a form of radial tear that involves the central attachment of the meniscus (12a). this may extend to to the mid body." is this a bucket tear? 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. The shape of the meniscus is formed at the eighth week of 800-688-2421. CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. Tachibana Y, Yamazaki Y, Ninomiya S. Discoid medial meniscus. The meniscal repair is intact. Diagnosis of recurrent meniscal tears: prospective evaluation of conventional MR imaging, indirect MR arthrography, and direct MR arthrography. Most horizontal tears extend to the inferior articular surface. Continuous meniscal tissue bridged the anterior and posterior horns of the lateral meniscus on 3 consecutive sagittal slices (Figure 1B). Figure 7: Meniscofemoral ligament. 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). On sagittal proton-density and T2-weighted images, this lesion was demonstrated by sensitive but nonspecific signs, such as the flipped meniscus . The medial meniscus is asymmetrical with a larger posterior horn. He presented after a few months with symptoms of instability. has shown that 41% of patients with a surgically confirmed torn post-operative meniscus had signal intensity within the meniscus extending into the articular surface which was lower than the signal intensity of gadolinium contrast.14 Like the presence of a line of intermediate T2 signal extending into the articular surface on conventional MRI, diagnosis of a torn post-operative meniscus on MRI arthrography is challenging when the intra-meniscal signal intensity is not as bright as gadolinium contrast. Zonal variation is also seen in the density of meniscus cells and their phenotypes with a chondrocytic inner zone and fibroblastic outer zone. Repair techniques include side-to-side repair, stabilization with suture anchors, and the transtibial pull-out technique (figure 4).12. structure on sagittal images on T1, proton density, and fat-saturated Atypically thick and high location It splits into two bands at the PCL, named Humphry(anterior to the PCL) and Wrisberg (posterior to the PCL). medial meniscus are extremely uncommon and should not be a diagnostic Comparison of Postoperative Antibiotic Regimens for Complex Appendicitis: Is Two Days as Good as Five Days? of the transverse ligament is comparable to the general population.5. 2005; 234:5361. MR criteria for discoid lateral menisci are used for discoid medial Thus, the loss of the lateral meniscus can often lead to rather rapid onset of osteoarthritis. 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. The symptoms This is a well-done study with clinical correlation and adequate follow-up. Objectives: Low-field MRI at 0.55 Tesla (T) with deep learning image reconstruction has recently become commercially available. The Wrisberg variant may present with a (PubMed: 17114506), BakerJC, FriedmanMV, RubinDA (2018) Imaging the postoperative knee meniscus: an evidence-based review. described in thrombocytopenia absent radius syndrome (TAR syndrome).2,3 Bilateral hypoplasia of the medial meniscus has also been reported.4. in 19916. Dr. Michael Gabor answered Diagnostic Radiology 35 years experience No,: It doesn't sound like a bucket handle tear Lee S, Jee W, Kim J. tissue only persists at the edges, where differentiation into the of these meniscal variants is the discoid lateral meniscus, and the On MRI, longitudinal tears appear as a vertical line of abnormal signal contacting articular surface. 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. In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). 300). proximal medial tibia was convex and the distal medial femoral condyle No gadolinium extension into the meniscus on fat-suppressed sagittal T1-weighted (9B) post arthrogram view. Kelly BT, Green DW. varus deformity (Figure 3). Meniscal disorders: Normal, discoid, and cysts. Sagittal PD (. incomplete breakdown of the central meniscus, but this is now disputed, Anatomic variability and increased signal change in this area are commonly mistaken for tears. What is a Lateral Meniscus Tear? MR imaging is useful for evaluation of many possible complications following meniscal surgery. 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. 2006; 88:660667, Boutin RD, Fritz RC, Marder RA. Illustration of the transtibial pullout repair for a tear of the posterior horn medial meniscal root (arrow). There is a medial and a lateral meniscus. instance, tears of the lateral aspect of the anterior horn of the At surgery, the torn part of the meniscus was in the intercondylar notch and chewed up and not amenable to repair. Discoid lateral meniscus in children. 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. A classification system developed by the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine [, Longitudinal-vertical tear. Repair of posterior root tears are being performed with increased frequency over the past several years. The example above demonstrates the importance of baseline MRI comparison when evaluating the postoperative meniscus. Media community. In this case the roots remained intact at the bone bridge, but the meniscal allograft detached from the joint capsule at the posterior and middle third with displacement into the central weightbearing surface (arrowheads) on sagittal T2-weighted (17C) and fat-suppressed axial proton density-weighted (17D) images. We use cookies to create a better experience. : Complications in brief: arthroscopic partial meniscectomy. congenital absence of the cruciate ligaments. 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. Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. [emailprotected]. Heron, D, Bonnard C, Moraine C,Toutain A. Agenesis of cruciate Surgery is useful if they are unstable and flipping in and out of the joint causing pain. ligaments and menisci causing severe knee dysplasia in TAR syndrome. . Damaged meniscal tissue is removed with arthroscopic instruments including scissors, baskets and mechanical shavers until a solid tissue rim is reached with the meniscal remnant contoured, preserving of as much meniscal tissue as possible. Kijowski et al. Interested in Group Sales? The main functions Complex or deep radial tears were found in three of five cases of lateral meniscus extrusion and normal root. Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. Results: Arthroscopic examination of the anterior horn of the lateral meniscus in all 22 patients was normal. Type 1: A complete slab of meniscal tissue with complete tibial coverage. Congenital discoid cartilage. 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). for the ratio of the sum of the width of the anterior and posterior What is a Grade 3 meniscus tear? Lateral meniscus posterior horn peripheral longitudinal tear managed by repair. The tear was treated by partial meniscectomy at second surgery. Materials and methods . They divide the meniscus into superior and inferior halves (Fig. Both the healed peripheral tear and the new central tear were proved at second look arthroscopy. FSE T2-weighted images, with a slab-like appearance on coronal images. The meniscus is diffusely vascularized in early life but in adults, only 10-30% of the peripheral meniscus is vascularized, often referred to as the red zone. 2008; 32:212219, Magee T. Accuracy of 3-Tesla MR and MR arthrography in diagnosis of meniscal retear in the post-operative knee. discoid meniscus, although discoid medial menisci can occur much less diminutive (1 mm) with no increased signal to suggest root attachment An intact meniscal repair was confirmed at second look arthroscopy. It is often explained by fibers of the anterior cruciate ligament and the covering synovium . Note the symmetrical shape of the lateral meniscus (left) with similar size of the anterior and posterior horns. 2020;49(1):42-49. There is no universally accepted system for classifying meniscal tear patterns. > 20% ratio of meniscus to tibia on the coronal image; Minimum diameter 14-15 mm on a midcoronal image; 75% The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. Semin Musculoskelet Radiol 2005;9(2):11624, Chung KS, Ha JK, Ra HJ, Nam GW, Kim JG. A 2008;191(1):81-5. Bilateral discoid medial menisci: Case report. The patient underwent meniscal repair but had recurrent pain prompting repeat MRI 8 months post-operative. Most lateral meniscal tears are due to twisting or turning activities or falls. CT arthrography is a recommended alternative for patients who are not MR eligible. Meniscal tears are common and often associated with knee pain. Radial tears comprise approximately 15 % of tears in some surgical series [. collapse and widening of the medial joint space (Figure 7). Most patients are asymptomatic, but injury to the meniscus can Clark CR, Ogden JA. ; Lee, S.H. Symptomatic anomalous insertion of the medial meniscus. As DLM is a congenital anomaly, the ultrastructural features and morphology differ from those of the normal meniscus, potentially leading to meniscal tears. They often tend to be radial tears extending into the meniscal root. Of these patients treated nonoperatively, 6 had a diagnosis of an isolated anterior horn tear on MRI. There are 3 main types, according to the Watanabe classification:18. Additionally, the postoperative complication of new extensive synovitis is apparent on the axial view (18D). Anatomic variability and increased signal change in this area are commonly mistaken for tears. of the anterior horn of the medial meniscus, an inferior patella plica, mesenchymal mass that differentiates into the tibia, femur, and What is your diagnosis? The purpose of our study was to determine if cysts of the ACL are the origin of cysts adjacent to the AHLM. joint, and they also protect the hyaline cartilage. 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. tear. The posterior root of the lateral meniscus (PRLM) attaches along the posterior aspect of the intercondylar eminence of the tibia (Fig. A tear of the ACL should also, in practice, not be a is in fact reducing the volume of the meniscus and restoring a normal problem in practice. It can be divided into five segments: anterior horn, anterior, middle and posterior segments, and posterior horn. variant, and discoid medial meniscus. They were first described by M J Pagnaniet al. While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. Kim SJ, Choi CH. 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. normal knee. This case features the following signs of meniscal tear: Case courtesy, Prof. Dr. Khaled Matrawy, Professor of radiology, Alexandria university, Egypt. an adult), and approximately twice the size of the anterior horn on Because this is a relatively new procedure, few studies have been dedicated to MRI evaluation of postoperative root repair. 2012;199(3):481-99. 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. Imaging characteristics of the 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).