Anatomic variability and increased signal change in this area are commonly mistaken for tears. discoid lateral meniscus, including a propensity for tears to occur and 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. The self-reported complication rate for partial meniscectomy is 2.8% and meniscus repair is 7.6%. Repair techniques include side-to-side repair, stabilization with suture anchors, and the transtibial pull-out technique (figure 4).12. Wrisberg variant, the morphology of the meniscus may be normal, but the Radial Meniscal Tear - ProScan Education - MRI Online 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 medial meniscus is asymmetrical with a larger posterior horn. Resnick D, Goergen TG, Kaye JJ, et al. 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. Anterior lateral cysts extended . Meniscal surgery is common and requires accurate post-operative imaging interpretation to guide the treatment approach. Brody J, Lin H, Hulstyn M, Tung G. Lateral Meniscus Root Tear and Meniscus Extrusion with Anterior Cruciate Ligament Tear. Illustration of the medial and lateral menisci. It is often explained by fibers of the anterior cruciate ligament and the covering synovium . While this test will show a tear up to 90% of the time, it does not always. horn of the lateral meniscus, and oblique tear orientation In the present study, the patients analyzed came from the have been the most difficult for imaging planes to visualize same geographical area . Singh K, Helms CA, Jacobs MT, Higgins LD. Of these patients treated nonoperatively, 6 had a diagnosis of an isolated anterior horn tear on MRI. History of a longitudinal medial meniscus tear managed by repair and concurrent ACL reconstruction. Which meniscus is more likely to tear? 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 MRI also demonstrated moderate degenerative spurring at the lateral joint compartment, a large knee joint effusion with . 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. Footballer's Lateral Meniscus: Anterior Horn Tears of the Lateral A tear of the ACL should also, in practice, not be a This emphasizes the importance of meniscal repair over meniscectomy when possible and the need for meniscal preservation when a partial meniscectomy is necessary. A 64-year-old female with no specific injury presented with knee pain, swelling, and locking that she first noticed after working out at the gym. The most common Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. 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. Posterior Horn Medial Meniscus Tears - Howard J. Luks, MD 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. Knee Surg Sports Traumatol Arthrosc. Sagittal proton density-weighted image (9A) demonstrates no high signal abnormality. Meniscus | Radiology Key For information on new subscriptions, product Check for errors and try again. The fat-suppressed sagittal T1-weighted post arthrogram view (7C) demonstrates gadolinium extending into the meniscal substance. attachment of the posterior horn is the Wrisberg meniscofemoral 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. 4. mesenchymal mass that differentiates into the tibia, femur, and Lateral Meniscus - ProScan Education - MRI Online Source: Shepard MF, et al. For root tears in general, sagittal imaging may demonstrate a meniscal ghost sign. Type 1: A complete slab of meniscal tissue with complete tibial coverage. However, many clinicians opt to use conventional MRI as the initial postoperative imaging study and reserve MR arthrography for equivocal cases. (as previously described), meniscal cyst,26 discoid lateral meniscus in the same knee (Figure 9),25 and pathologic medial patella plica.27. | 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. noted to be diminutive, with the posterior horn measuring 7 mm to 8 mm. We look forward to having you as a long-term member of the Relias be misinterpreted for more significant pathology on MRI. 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. posterior horn of the medial meniscus include a triangular hypointense Repair of posterior root tears are being performed with increased frequency over the past several years. It can be divided into five segments: anterior horn, anterior, middle and posterior segments, and posterior horn. 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. This arises from the posterior horn of the lateral meniscus and attaches to the lateral aspect of the medial femoral condyle. We will review the common meniscal variants, which 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. Kim SJ, Choi CH. American Board of Orthopaedic Surgery Practice of the Orthopaedic Surgeon: Part-II, certification examination case mix. Conventional MRI is useful for evaluation of posterior root morphology at the tibial tunnel fixation site, meniscal extrusion and articular cartilage. 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. is much greater than in a discoid lateral meniscus, and the prevalence What are the findings? AJR Am J Roentgenol 211(3):519527, De Smet AA. De Smet A. Sagittal proton density-weighted image (10A) demonstrates increased signal extending to the articular surface consistent with granulation tissue. The posterior horn is always larger than the anterior horn. Disadvantages include patient discomfort, increased cost, physician time needed for the procedure and radiation exposure during fluoroscopy. 5 In the first instance, tears of the lateral aspect of the anterior horn of the medial meniscus are extremely uncommon and should not be a diagnostic Is sport activity possible after arthroscopic meniscal allograft transplantation? 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. 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. Learn more. According to one source, they are thought to account for ~10% of all arthroscopic meniscectomies 5. The posterior root of the lateral meniscus (PRLM) attaches along the posterior aspect of the intercondylar eminence of the tibia (Fig. 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. Discoid lateral meniscus: Prevalence of peripheral rim instability. As visualized on sagittal MR images, the anterior horn of the medial meniscus is shorter than the posterior horn, whereas the anterior and posterior horns of the lateral meniscus are of equal length. The most widely used diagnostic modalities to assess the ligament injuries are arthroscopy and Magnetic Resonance Imaging (MRI). 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. MRI of the knee is commonly indicated for evaluation of unresolved or recurrent knee pain following meniscal surgery. show cupping of the medial tibial plateau, proximal medial tibial physis Otherwise, the increased vascularity in children has sometimes led to false-positive reading of a meniscus tear. Flipped meniscus - anterior horn lateral meniscus | Radiology Case In cases like this, MR arthrography is quite helpful. Bilateral Hypoplasia of the Medial and Lateral Menisci - PMC The lateral . meniscal injury. Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. They were first described by M J Pagnaniet al. 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. Discoid lateral meniscus in children. However, the tear changes plane of orientation over its course. Radial or oblique tear congurations close to or within the meniscus . On MRI, they exhibit abnormal horizontal linear signal contacting the inferior articular surface near the free edge or less commonly the superior surface. 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. 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. A tear of the meniscal root means the tear is near where it attaches to the bone, usually far in the back. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. are reported cases of complete absence of the medial meniscus as 5. These are like large radial tears and can destabilize a large portion of the meniscus. Posterior meniscal root repairs: outcomes of an anatomic transtibial pull-out technique. 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 . Most studies have shown increased accuracy for direct and indirect MR arthrography compared to conventional MRI for partial meniscectomies of 25% or more.16. These findings are also frequently associated with genu 1. Symptoms of anterior horn tears were very similar to those of meniscal tears of the midbody or posterior horn, including catching, pain with knee flexion, and swelling. of the menisci can be summarized as providing: Clark and Ogden studied the natural development of the menisci in the Extension to the anterior cortex of . The sensitivity of mri in detecting meniscal tears is generally good, ranging from 70-98%, with specificity in the same range in many studies. 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 . 300). Weight-bearing knee X-rays showed a 50 % narrowing in the medial compartment. Associated anomalies in a discoid medial Radial Tear of the Medial Meniscal Root: Reliability and Accuracy of MRI for Diagnosis. The congenitally absent meniscus appears to influence the development is in fact reducing the volume of the meniscus and restoring a normal View Mostafa El-Feky's current disclosures, see full revision history and disclosures, Flipped meniscus - anterior horn lateral meniscus, Disproportionate posterior horn sign (meniscal tear). The ends of the anterior and posterior horns are firmly attached to the tibia at their roots. At the time the article was created Yuranga Weerakkody had no recorded disclosures. Reference article, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-40036, {"containerId":"expandableQuestionsContainer","displayRelatedArticles":true,"displayNextQuestion":true,"displaySkipQuestion":true,"articleId":40036,"questionManager":null,"mcqUrl":"https://radiopaedia.org/articles/meniscal-root-tear/questions/1112?lang=us"}. 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. Longitudinal lateral meniscus tear status post repair (arrow). The main functions of the Wrisberg ligament in patients with a complete lateral discoid 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. Neuschwander DC, Drez D Jr, Finney TP. Arthroscopy: The Journal of Arthroscopic & Related Surgery. A tear of the lateral meniscus can occur from a sudden injury, or from chronic wear and overload. {"url":"/signup-modal-props.json?lang=us"}, El-Feky M, Flipped meniscus - anterior horn lateral meniscus. An algorithm for computing tear meniscus profile ligaments and menisci causing severe knee dysplasia in TAR syndrome. At the time the article was last revised Yahya Baba had A previous study by De Smet et al. variant, and discoid medial meniscus. this may extend to to the mid body." is this a bucket tear? Coronal extrusion of the lateral meniscus does not increase after On this page: Article: Epidemiology Pathology Radiographic features History and etymology Factors affecting meniscal extrusion: correlation with MRI, clinical Increased intrameniscal signal is commonly seen in the transplanted allograft but does not correlate with clinical outcome. 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. On the sagittal fat-suppressed T2-weighted image (7B), fluid extends into the tear. 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. the posterior horn is usually much larger than the anterior horn (the Most horizontal tears extend to the inferior articular surface. However, this conjecture and others pre- highest.13,27,34,42 Tear locations, such as the posterior sented in literature are mostly speculative. 2008;191(1):81-5. trials, alternative billing arrangements or group and site discounts please call Fellowship-trained musculoskeletal radiologists read 99% of the MRIs. discoid meniscus, although discoid medial menisci can occur much less What causes abnormal mobility in the medial meniscus? incomplete breakdown of the central meniscus, but this is now disputed, Meniscal transplants can fail at the implantation site by avulsion, failure of bone plug incorporation or bone bridge fracture. Of the 54 participants, 5 had PHLM tears and 49 were normal. A Wrisberg type variant has not been documented in Dr. Michael Gabor answered Diagnostic Radiology 35 years experience No,: It doesn't sound like a bucket handle tear Monllau J, Gonzalez G, Puig L, Caceres E. Bilateral hypoplasia of the medial meniscus. congenital absence of the cruciate ligaments. Best assessed on T2 weighted sequences. of the meniscus. the medial meniscus. The camera can visualize the meniscus and other structures within the knee. Both the healed peripheral tear and the new central tear were proved at second look arthroscopy. In these cases, surfacing meniscal signal on low TE series may represent recurrent tear, granulation tissue or residual grade 2 degenerative signal that contacts the meniscal surface after debridement. hypermobility. With age, increased connective tissue stiffness of the meniscus develops secondary to elastin degradation and collagen rigidification.2. {"url":"/signup-modal-props.json?lang=us"}, Weerakkody Y, Baba Y, Knipe H, et al. 3. Menisci are present in the knees and the 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. runs from the anterior horn of the medial meniscus to either the ACL or Efficacy of Arthroscopic Treatment for Concurrent Medial Meniscus You can use Radiopaedia cases in a variety of ways to help you learn and teach. 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. History of longitudinal medial meniscus tear managed by meniscal repair (arrows). Description. menisci occurs. 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. Discoid lateral meniscus and the frequency of meniscal tears. The anterior meniscofemoral ligament (Humphrey ligament) attaches proximally on the medial femoral condyle, inferior to the PCL insertion. Thompson WO, Thaete FL, Fu FH, Dye SF. MRI appearance of Wrisberg variant of discoid lateral meniscus. What is a Grade 3 meniscus tear? 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. 1991;7(3):297-300. 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). And, some tears do not fill with contrast during arthrography. The patient underwent meniscal repair but had recurrent pain prompting repeat MRI 8 months post-operative. 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. instance, tears of the lateral aspect of the anterior horn of the Discoid lateral meniscus of the knee joint: Nature, mechanism, and operative treatment. meniscus. 6 months post-operative she had increased pain prompting follow-up MRI. normal knee. There was no history of a specific knee injury. In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). separate the cavity. Lateral meniscus extrusion was present in six (23%) of 26 LMRTs and five (2.2%) of 231 patients with normal meniscus roots ( P < .001). 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 In this case, we can determine that there is a new tear in a different location. ligament will help to exclude these conditions.5 In the first Concise, to-the-point text covers MRI for the entire musculoskeletal system, presented in a highly templated format. Meniscal root tear. 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. Anomalous insertion of anterior and posterior horns of medial meniscus There are of the AIMM into the ACL is classified as Type 1 (inferior third), Type 2 Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. They often tend to be radial tears extending into the meniscal root. slab-like configuration on sagittal MR images, with > 3 bowties Congenital discoid cartilage. Case study, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-75066. does not normally occur.13. 2012;199(3):481-99. Generally, Am J Sports Med 2017; 45:884891, Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, et al. On sagittal proton-density and T2-weighted images, this lesion was demonstrated by sensitive but nonspecific signs, such as the flipped meniscus . frequently. Both horns of the medial meniscus are triangular with sharp points. Meniscal extrusion. Medical search. Web hypoplastic meniscus was not the cause of the patients pain, suggesting The anterior and posterior meniscofemoral ligaments (Humphrey and Wrisberg respectively) are commonly present with one or both found in 93-100% of patients. Knee Examination - Samarpan Physio Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. signal fluid cleft interposed between the posterior horn and the capsule 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. medial meniscus, discoid lateral meniscus, including the Wrisberg problem in practice. 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. 4). meniscus are not uncommon; they include an anomalous insertion of the The lateral meniscus attaches to the popliteus tendon and capsule via the popliteomeniscal fascicles at the posterior horn and to the medial femoral condyle by the meniscofemoral ligaments. 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. Conventional MRI is the least invasive modality for evaluation of a meniscal repair but has lower sensitivity, specificity and accuracy than direct or indirect arthrographic MRI. Incidence and Detection of Meniscal Ramp Lesions on Magnetic Resonance Medial meniscus posterior horn peripheral longitudinal tear treated with repair. 2. The patient failed conservative management of aspiration and cortisone injection. 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. On examination, the patient had medial joint line tenderness with positive McMurray test. They may not even be apparent with an arthroscopic examination. Lateral Meniscus: Anatomy The lateral meniscus is seen as a symmetric bow tie in the sagittal plane on at least one or two sections before it divides into two asymmetric triangles near the midline.
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