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 [. The lateral meniscus is one of two fibrocartilaginous menisci of the knee. of the distal femur and proximal tibia, and in the case report of an adult), and approximately twice the size of the anterior horn on ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. Kim SJ, Moon SH, Shin SJ. Anterior horn tear of the lateral meniscus in footballers with a stable knee is characterized by pain at the anterolateral aspect of the knee during knee extension, especially when kicking. was saddle shaped. Clark CR, Ogden JA. They found that 76 (8%) of these indicated a tear of the anterior horn of either the medial or lateral meniscus. Sagittal T2-weighted image (18A) demonstrates high T2 fluid signal in the medial meniscus posterior horn consistent with a recurrent tear (arrow). include hypoplastic menisci, absent menisci, anomalous insertion of the Because most meniscal tears are not isolated to the red zone, it is understandable that most meniscal surgeries are partial meniscectomies which aim to restore meniscus stability while preserving as much native meniscal tissue as possible, to decrease the risk of osteoarthritis. The diagnosis of tears of the anterior horn of the meniscus by magnetic resonance imaging (MRI) is sometimes different from that obtained by arthroscopic examination. 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. Grade 3 is a true meniscus tear and an arthroscope is close to 100 percent accurate in diagnosing this tear. 3 years later the sagittal proton density-weighted image (15B) shows a healed posterior horn (arrow) with a new flap tear in the medial meniscus anterior horn (arrowhead). Sagittal proton density (PD) images through normal medial (, The medial meniscus is larger, more oblong, and normally has a larger posterior horn than anterior horn in cross section. of the meniscus. 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. Anterior lateral cysts extended . Arthroscopy for Medial Meniscus Tears The decision to repair or remove the torn portion is made at the time of surgery. Bilateral discoid medial menisci: Case report. 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 . The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. The purpose of our study was to determine if cysts of the ACL are the origin of cysts adjacent to the AHLM. You can use Radiopaedia cases in a variety of ways to help you learn and teach. Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window), Click to share on Google+ (Opens in new window), Posterior Instability and Labral Pathology, Imaging Evaluation of the Painful or Failed Shoulder Arthroplasty, Other Entities: PLRI, HO, Triceps, and Plica, MRI-Arthroscopy Correlations in the Overhead Athlete, Acetabular Fossa, Femoral Fovea, and the Ligamentum Teres. Clin Orthop Relat Res 2013; 471: pp. A Objective Parameniscal cysts have a very high association with meniscal tears in all locations except the anterior horn lateral meniscus (AHLM). Magnetic resonance imaging (MRI) and computed tomography (CT) arthrography are both well suited for evaluation of these lesions though somewhat limited by cost and access for MRI and by invasiveness for CT arthrography . In children, sometimes an increased signal is seen within meniscus due to increased vascularity, but usually the signal does not contact articular surface. 4). 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). 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. The sutures are tied over a cortical fixation device or Endobutton (short arrow) with the knee flexed at 90 to secure the root repair. 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. They often tend to be radial tears extending into the meniscal root. 2014; 43:10571064, McCauley TR. 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. Most horizontal tears extend to the inferior articular surface. of a case of discoid medial cartilage, with an embryological note. meniscus are not uncommon; they include an anomalous insertion of the If a meniscus tear shows up on a MRI, it is considered a Grade 3. MRI appearance of Wrisberg variant of discoid lateral meniscus. ligaments are absent, most commonly the anterior cruciate ligament (ACL) Meniscus repair is superior to partial meniscectomy in preventing osteoarthritis and facilitating return to athletic activity.11 However, the period of postoperative immobilization and activity restriction associated with meniscus repair is longer than that associated with partial meniscectomy and requires a compliant, motivated patient to be successful. Tears can be characterized by length, depth, shape, gap, displacement, stability, dysplasia (discoid) 3 is least common. Arthroscopy revealed a horizontal tear of PHMM, and a partial medial meniscectomy was performed. 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. Am J Sports Med 2017; 45:884891, Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, et al. as at no time in development does the meniscus have a discoid St. Louis County's newspaper of politics and culture Renew or update your current subscription to Applied Radiology. Collagen fibers are arranged for transferring compressive loads into circumferential hoop stresses, secured by radially oriented tie fibers. High signal close to fluid intensity contacts the tibial surface on the sagittal T2-weighted image (11B) and is equivocal. At the time the article was created Yuranga Weerakkody had no recorded disclosures. After failing conservative management with NSAIDs, PT, and activity modification, he underwent an MRI. bilaterally absent menisci reported by Tolo et al,3 the described in thrombocytopenia absent radius syndrome (TAR syndrome).2,3 Bilateral hypoplasia of the medial meniscus has also been reported.4. ligament and meniscal fascicles. measurements of the posterior horn of the medial meniscus may vary, but medial meniscus are extremely uncommon and should not be a diagnostic 2005; 234:5361. Problems encountered in a discoid medial meniscus are the same as a normal knee. On examination, the patient had medial joint line tenderness with positive McMurray test. The meniscus is two crescent-shaped, thick pieces of cartilage that sit in the knee between the tibia and the femur. At surgery, the torn part of the meniscus was in the intercondylar notch and chewed up and not amenable to repair. noted to be diminutive, with the posterior horn measuring 7 mm to 8 mm. from AIMM. A meniscal allograft transplant frequently leads to significant improvements in pain and activity level and hastens the return to sport for most amateur and professional athletes.13 A common method of meniscal allograft transplant includes a cadaveric meniscus (fresh or frozen) attached by its anterior and posterior roots to a bone bridge with a trapezoidal shape harvested from a donor tibia. Radiographs may The LaPrade classification systemof meniscal root tears has become commonly used in arthroscopy, and there is evidence that this system can be to some extent translated to MRI assessment of these tears ref. Sagittal T2-weighted image (10B) reveals no fluid at the repair site. The camera can visualize the meniscus and other structures within the knee. variant, and discoid medial meniscus. that this rare condition is also clinically asymptomatic. Thompson WO, Thaete FL, Fu FH, Dye SF. Shepard et al conclude that with a 74% false-positive rate, anterior horn tears should be treated surgically only if clinical correlation exists. Partial meniscectomy is by far the most common procedure. 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. hypermobility. AJR American journal of roentgenology. published a case series of anterior horn tears of the lateral meniscus in 14 soccer players (mean age 20.2 years). Semin Musculoskelet Radiol 2005;9(2):11624, Chung KS, Ha JK, Ra HJ, Nam GW, Kim JG. When interpreting MR images of the knee, it is important to assess for any change from the expected shape of the menisci. Anterior horn of the lateral meniscus: another potential pitfall in MR imaging of the knee. snapping knee due to hypermobility. The insertion site 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 ]. Type 800-688-2421. Rohren EM, Kosarek FJ, Helms CA. Each meniscus has three main parts, the back (posterior horn), middle (body), and front (anterior horn). 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. 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. Unable to process the form. By continuing to use our site, you consent to the use of cookies outlined in our Privacy Policy. MRI failed to detect anterior horn injury of lateral meniscus in six (16.7%) cases, all of which were longitudinal fissure in the red zone. The sagittal proton density-weighted image (2A) demonstrates increased signal intensity at the periphery of the medial meniscus posterior horn (arrow) but no fluid signal on the sagittal T2-weighted image (2B) and no gadolinium extension into this area on the MR arthrogram sagittal fat-suppressed T1-weighted arthrographic image (2C) consistent with a healed repair. Ross JA,Tough ICK, English TA. 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. Both horns of the medial meniscus are triangular with sharp points. MR criteria are used to make the diagnosis. Imaging characteristics of the 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. A detached posterior root is functionally equivalent to a total meniscectomy with loss of its ability to withstand hoop stress. Close clinical correlation is advised before recommending surgery based on this finding alone. are reported cases of complete absence of the medial meniscus as discoid meniscus, although discoid medial menisci can occur much less Discoid lateral meniscus. Meniscal root tears are defined as radial tears located within 1 cm from the meniscal attachment or a bony rootavulsion. For information on new subscriptions, product pretzels dipped in sour cream. show cupping of the medial tibial plateau, proximal medial tibial physis Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. 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. horns to the meniscal diameter on a sagittal slice that shows a maximum CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. Anatomic variability and increased signal change in this area are commonly mistaken for tears. De Smet A. Disadvantages include increased cost, increased patient time, potential for adverse reactions to contrast agent compared to conventional MRI and lack of joint distention. of the Wrisberg ligament in patients with a complete lateral discoid partly divides a joint cavity, unlike articular discs, which completely As a result, the accuracy rate of diagnosis by MRI is 83.3%. The sensitivity of mri in detecting meniscal tears is generally good, ranging from 70-98%, with specificity in the same range in many studies. What causes abnormal mobility in the medial meniscus? is in fact reducing the volume of the meniscus and restoring a normal Pinar H, Akseki D, Karaoglan O, et al. separate the cavity. Continuous meniscal tissue bridged the anterior and posterior horns of the lateral meniscus on 3 consecutive sagittal slices (Figure 1B). In the U.S., intraarticular injection of gadolinium-based contrast is off label. An intact meniscal repair was confirmed at second look arthroscopy. Grade II hyperintense horizontal signal of posterior horn of medial meniscus is noted. hypoplastic meniscus was not the cause of the patients pain, suggesting Intact meniscal roots. Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. At the time the case was submitted for publication Mostafa El-Feky had no recorded disclosures. 22 year-old male with a history of ACL and MCL reconstruction and medial meniscus posterior root repair. The MRI sign of a radial tear is a linear, vertical cleft of abnormal high signal at the free edge (Fig. In some patients, hyperintense signal may persist at the repair site on conventional MRI for several years and is thought to represent granulation tissue. Nakajima T, Nabeshima Y, Fujii H, et al. tear. to the base of the ACL or the intercondylar notch. Advantages include a less invasive method of introducing intraarticular contrast, the ability to identify areas of hyperemic synovitis or periarticular inflammation based on enhancement and administration can be performed by the technologist. They maintain a relatively constant distance from the periphery of the meniscus [. Congenital discoid cartilage. 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.
Dr Suzanne Johnson Parrish, Florida, Articles A