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. > 20% ratio of meniscus to tibia on the coronal image; Minimum diameter 14-15 mm on a midcoronal image; 75% 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. 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. 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. Media community. Klingele KE, Kocher MS, Hresko MT, et al. Kim SJ, Moon SH, Shin SJ. Concise, to-the-point text covers MRI for the entire musculoskeletal system, presented in a highly templated format. This is a critical differentiation because the latter represents meniscal tears that can be St. Louis County's newspaper of politics and culture On the proton density-weighted image (12A) persistent high signal extends to the tibial and femoral surfaces (arrow). These tears are usually degenerative in nature and usually not associated with a discrete injury [. 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. 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. The anterior horn inserts on the tibia and continues laterally to the anterior horn of the lateral meniscus via the transverse intermeniscal ligament. Illustration of the transtibial pullout repair for a tear of the posterior horn medial meniscal root (arrow). However, recognizing these variants is important, as they can Meniscal surgery is common and requires accurate post-operative imaging interpretation to guide the treatment approach. is much greater than in a discoid lateral meniscus, and the prevalence The torn edges are aligned, and stable fixation applied with sutures or bioabsorbable implants at approximately 5 mm intervals. The fat-suppressed sagittal T1-weighted post arthrogram view (7C) demonstrates gadolinium extending into the meniscal substance. Thompson WO, Thaete FL, Fu FH, Dye SF. What causes abnormal mobility in the medial meniscus? AJR Am J Roentgenol 211(3):519527, De Smet AA. The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). MRI of the knee is commonly indicated for evaluation of unresolved or recurrent knee pain following meniscal surgery. MR criteria are used to make the diagnosis. 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. Meniscal root tears are defined as radial tears located within 1 cm from the meniscal attachment or a bony rootavulsion. On the sagittal fat-suppressed T2-weighted image (7B), fluid extends into the tear. Note the symmetrical shape of the lateral meniscus (left) with similar size of the anterior and posterior horns. Skeletal radiology. Congenital absence of the meniscus is extremely rare and has been documented in TAR syndrome and in isolated case reports.2,3 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). 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). Kelly BT, Green DW. and ACL tears can be mistaken for AIMM, but carefully tracing the Generally, 7 Therefore, it is important for the radiologist to be familiar with the appearance of a recurrent tear versus an untorn postoperative meniscus. seen on standard 4- to 5-mm slices.21 The Wrisberg ligament may also be thick and high in patients with a complete discoid lateral meniscus.22 Other criteria used to diagnose lateral discoid meniscus include the following: In the 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. problem in practice. Nakajima T, Nabeshima Y, Fujii H, et al. Problems encountered in a discoid medial meniscus are the same as a Because there is less pressure on the meniscus there, it is difficult to evaluate the anterior region of the meniscus. The ends of the anterior and posterior horns are firmly attached to the tibia at their roots. Knee Surg Sports Traumatol Arthrosc 2011; 19:147157, Gwathmey F.W., Golish S.R., Diduch D.R., et al: Complications in brief: meniscus repair. The tear was treated by partial meniscectomy at second surgery. MRI appearance of Wrisberg variant of discoid lateral meniscus. 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. Root tears are associated with a high risk for osteoarthritis. Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation. Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. Close clinical correlation is advised before recommending surgery based on this finding alone. No meniscal tear is seen, but the root attachment was also noted to be The medial compartment articular cartilage is preserved, and the meniscal body is not significantly extruded (16D). Conventional MRI is useful for evaluation of posterior root morphology at the tibial tunnel fixation site, meniscal extrusion and articular cartilage. Renew or update your current subscription to Applied Radiology. joint: Morphologic changes and their potential role in childhood The medial meniscus is asymmetrical with a larger posterior horn. Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. 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. It is important to know the age of the patient when interpreting the MRI. 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. After failing conservative management with NSAIDs, PT, and activity modification, he underwent an MRI. 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 . menisci (Figure 8). no specific MR criteria for classifying discoid medial menisci, and the Pathology - a tear that has developed gradually in the meniscus. Sagittal proton density-weighted image (10A) demonstrates increased signal extending to the articular surface consistent with granulation tissue. to tear. The common insertion of the anterior cruciate ligament (ACL) and the AHLM root may provide a pathway for disease. Check for errors and try again. Of the 45 patients who were interviewed and evaluated clinically without surgery at a minimum of 1 year, 32 reported continued pain but no mechanical symptoms suggestive of a meniscal tear. Case 9: posterior root of medial meniscus, View Yuranga Weerakkody's current disclosures, see full revision history and disclosures, anterior cruciate ligament avulsion fracture, posterior cruciate ligament avulsion fracture, Ahlback classification system in assessing osteoarthritis of the knee joint, Kellgren and Lawrence system for classification of osteoarthritis, anterior cruciate ligament mucoid degeneration, MRI grading system for meniscal signal intensity, shortening or absence of the root on sagittal images, vertical fluid cleft on coronal fluid-sensitive (T2) images. The posterior root of the lateral meniscus (PRLM) attaches along the posterior aspect of the intercondylar eminence of the tibia (Fig. Figure 7: Meniscofemoral ligament. Sagittal T2-weighted image (10B) reveals no fluid at the repair site. 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 Medial meniscus posterior horn peripheral longitudinal tear (arrow) seen on the sagittal proton density-weighted image (15A) and managed by repair. | 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. Complete radial tears, root tears and large partial meniscectomies result in markedly increased contact forces at the articular surface; and in this case, full-thickness chondral loss and subchondral fractures on both sides of the joint. reported.4. According to one source, they are thought to account for ~10% of all arthroscopic meniscectomies 5. Menisci ensure normal function of the It has been calculated that the lateral meniscus absorbs about 70% of the forces across the lateral compartment of the knee. 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. Interested in Group Sales? This scan showed a radial MMT. For root tears in general, sagittal imaging may demonstrate a meniscal ghost sign. 2012;199(3):481-99. 5. That reported case was also associated with 70 year-old female with history of medial meniscus posterior horn radial tear. 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. ligaments are absent, most commonly the anterior cruciate ligament (ACL) Repair of posterior root tears are being performed with increased frequency over the past several years. 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. 3 is least common. Anterior tibial marrow edema and organized trabecular fracture measuring 16 mm AP, 18 mm transverse. 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.
anterior horn lateral meniscus tear: mri