the menisci of the knees. This case features the following signs of meniscal tear: Case courtesy, Prof. Dr. Khaled Matrawy, Professor of radiology, Alexandria university, Egypt. 2006; 88:660667, Boutin RD, Fritz RC, Marder RA. There was no history of a specific knee injury. Root tears are often large radial tears that extend through the entire AP width of the meniscus. trauma; however, other symptoms include clicking, snapping, and locking The example above demonstrates the importance of baseline MRI comparison when evaluating the postoperative meniscus. from AIMM. The meniscus may also become hypertrophic. For DSR inquiries or complaints, please reach out to Wes Vaux, Data Privacy Officer, The most widely used diagnostic modalities to assess the ligament injuries are arthroscopy and Magnetic Resonance Imaging (MRI). with mechanical features of clicking and locking. On this page: Article: Epidemiology Pathology Radiographic features History and etymology History of longitudinal medial meniscus tear managed by meniscal repair (arrows). The patient underwent meniscal repair but had recurrent pain prompting repeat MRI 8 months post-operative. Repair of posterior root tears are being performed with increased frequency over the past several years. While this test will show a tear up to 90% of the time, it does not always. Long-term outcome after arthroscopic meniscal repair versus arthroscopic partial meniscectomy for traumatic meniscal tears. Pathology - a tear that has developed gradually in the meniscus. . Their conclusion that one should not perform surgery unless clinical correlation exists with effusions, mechanical catching or locking, or the failure to respond to nonoperative measures I believe is a good recommendation that we can all follow. discoid lateral meniscus, including a propensity for tears to occur and 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. Clin Orthop Relat Res 2013; 471: pp. Generally, The same imaging criteria (as for the case of greater than 25% partial meniscectomy), the presence of fluid signal on T2-weighted or contrast extending into the meniscal substance is used to diagnose a recurrent tear. For root tears in general, sagittal imaging may demonstrate a meniscal ghost sign. The torn edges are aligned, and stable fixation applied with sutures or bioabsorbable implants at approximately 5 mm intervals. Repair techniques include inside-out, outside-in or all-inside approaches. Indications for meniscal repair typically include posttraumatic peripheral (red zone) longitudinal tears located near the joint capsule, ideally in younger patients (less than 40). Menisci are present in the knees and the In the previously reported cases, as well as in this case, the Volunteerism and Sports Medicine: Where do We Stand? If a meniscus tear shows up on a MRI, it is considered a Grade 3. Meniscal root tears are defined as radial tears located within 1 cm from the meniscal attachment or a bony rootavulsion. Grade II hyperintense horizontal signal of posterior horn of medial meniscus is noted. Type 2: An incomplete slab of meniscal tissue with 80% coverage of the lateral tibial plateau. Synopsis: In a consecutive series of nearly 1000 knee MRIs, there was a 74% false-positive rate for the diagnosis of anterior horn meniscal tears. The congenitally absent meniscus appears to influence the development snapping knee due to hypermobility. 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. Anomalous 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. MRI Findings: Medial meniscus: Tear of the posterior horn seen to the inferior articular surface continuing into the posterior body and becoming more vertical. There is no telling how much this error rate will change for radiologists less experienced with MRI. Case study, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-75066. Clark CR, Ogden JA. 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. high fibula head and a widened lateral joint space.20 Several 9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion. 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. Radiology. Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. The common insertion of the anterior cruciate ligament (ACL) and the AHLM root may provide a pathway for disease. Thompson WO, Thaete FL, Fu FH, Dye SF. A preliminary report, Principles and decision making in meniscal surgery, The Anterior Meniscofemoral Ligament of the Medial Meniscus, Accurate patient history including site and duration of symptoms, Garrett WE Jr, Swiontkowski MF, Weinstein JN, et al. 800-688-2421. Meniscal root tears are a type of meniscal tear in the knee where the tear extends to either the anterior or posterior meniscal root attachment to the central tibial plateau. Connolly B, Babyn PS, Wright JG, Thorner PS. 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. Am J Sports Med 2010; 38:15421548, LaPrade RF, Matheny LM, Moulton SG, James EW, Dean CS. described in thrombocytopenia absent radius syndrome (TAR syndrome).2,3 Bilateral hypoplasia of the medial meniscus has also been reported.4. The tear was treated by partial meniscectomy at second surgery. Neuschwander DC, Drez D Jr, Finney TP. Most horizontal tears extend to the inferior articular surface. 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. In cases like this, MR arthrography is quite helpful. Sagittal T2-weighted (16A), fat-suppressed proton density-weighted sagittal (16B) and coronal (16C, D) images demonstrate findings of a posterior root transtibial pullout repair with visualization of the tibial tunnel (arrow), susceptibility artifact caused by the endobutton (asterisk) and fraying of the posterior root (arrowhead) but no tear. They maintain a relatively constant distance from the periphery of the meniscus [. Nakajima T, Nabeshima Y, Fujii H, et al. Type 1: A complete slab of meniscal tissue with complete tibial coverage. Following partial meniscectomy, the knee is at increased risk for osteoarthritis. 1991;7(3):297-300. typically into the anterior cruciate ligament. Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. 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. Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. 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. 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. . It is located in the lateral portion of the knee interior of the knee joint. What causes abnormal mobility in the medial meniscus? ; Lee, S.H. Arthroscopy revealed a horizontal tear of PHMM, and a partial medial meniscectomy was performed. variant, and discoid medial meniscus. Medial meniscus bucket handle tears can result in a double PCL sign. Meniscal root tear. Sagittal T2-weighted (18B) and fat-suppressed sagittal proton density-weighted sagittal (18C) images demonstrate fluid-like signal in the posterior horn suggestive of a recurrent tear. The reported prevalence is 0.06% to 0.3%.25 However, the tear changes plane of orientation over its course. Tolo VT. Congenital absence of the menisci and cruciate ligaments of the knee: A case report. normal knee. 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. does not normally occur.13. Sagittal PD (. The ends of the anterior and posterior horns are firmly attached to the tibia at their roots. 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. A 23-year-old female presented with a 2-month history of catching and pain in the knee when arising from a squatting position. Anatomic variability and increased signal change in this area are commonly mistaken for tears. Seventy-four cases of bucket-handle tears (mean age, 27.2 11.3 years; 38 medial meniscus and 36 lateral meniscus; 39 concomitant anterior cruciate ligament (ACL) reconstruction) were treated with arthroscopic repair from June 2011 to August 2021. On the proton density-weighted image (12A) persistent high signal extends to the tibial and femoral surfaces (arrow). Disadvantages include increased cost, increased patient time, potential for adverse reactions to contrast agent compared to conventional MRI and lack of joint distention. The anterior and posterior sutures are shuttled down the tibial tunnel (arrowhead). Klingele KE, Kocher MS, Hresko MT, et al. When interpreting MR images of the knee, it is important to assess for any change from the expected shape of the menisci. 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. 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. In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). sagittal magnetic resonance (MR) images. Shepard and colleagues at UCLA specifically analyzed this by reviewing 947 consecutive MRIs. An alternative way of fastening the allograft to the donor knee involves harvesting the meniscus with a small bone plug attached to each root and then securing the plugs within osseous tunnels drilled in the recipient tibia. At the time the article was last revised Yahya Baba had AJR Am J Roentgenol. ligaments and menisci causing severe knee dysplasia in TAR syndrome. Pagnani M, Cooper D, Warren R. Extrusion of the Medial Meniscus. least common is complete congenital absence of the menisci. Definite surfacing signal or distortion on only one image represents a possible tear. hypoplastic meniscus was not the cause of the patients pain, suggesting 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 . 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. congenital anomalies affect the lateral meniscus, most commonly a Figure 7: Meniscofemoral ligament. 2020;49(1):42-49. Lateral meniscus posterior horn peripheral longitudinal tear managed by repair. To assess the prevalence of meniscal extrusion and its . Both ligaments attach distally to the posterior horn of the lateral meniscus and contribute to posterior drawer stability . this may extend to to the mid body." is this a bucket tear? both enjoyable and insightful. 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. 2002;30(2):189-192. variants of the meniscus are relatively uncommon and are frequently 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. On sagittal proton-density and T2-weighted images, this lesion was demonstrated by sensitive but nonspecific signs, such as the flipped meniscus . Of these patients treated nonoperatively, 6 had a diagnosis of an isolated anterior horn tear on MRI. Clinical imaging. partly divides a joint cavity, unlike articular discs, which completely This case is almost identical to the previous case with a different clinical history. Copy. 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 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. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. Tears Get unlimited access to our full publication and article library. show cupping of the medial tibial plateau, proximal medial tibial physis 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 10 Studies on meniscus root tears have investigated the relationship of osteoarthritis and an anterior cruciate ligament tear. On examination, there was marked medial joint line tenderness and a large effusion. problem in practice. 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 . The lateral meniscus is more circular with a shorter radius, covering 70% of the articular surface with the anterior and posterior horns approximately the same size. As a result, the accuracy rate of diagnosis by MRI is 83.3%. They often tend to be radial tears extending into the meniscal root. This case features the following signs of meniscal tear: absent bow tie appearance of the lateral meniscus ghost meniscus: empty location of the anterior horn of the lateral meniscus diagnostic dilemma, as the AIMM band will be seen to extend to the to the base of the ACL or the intercondylar notch. the rare ring-shaped meniscus, to the classification. meniscal diameter. Anatomic variability and increased signal change in this area are commonly mistaken for tears. There are 3 main types, according to the Watanabe classification:18. 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. Resnick D, Goergen TG, Kaye JJ, et al. This article focuses on For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. Pain is typically medial and activity-related (e.g. The insertion site immediatly lateral to the anterior horn of lateral meniscus and posterior to the tubercle of anteriro horn of medial meniscus . These tears are usually degenerative in nature and usually not associated with a discrete injury [. 3. Magnetic resonance imaging of the postoperative meniscus: resection, repair, and replacement. MRI plays a critical role in influencing the treatment decision and enables information that would obviate unnecessary surgery including diagnostic arthroscopy. 5. runs from the anterior horn of the medial meniscus to either the ACL or MR imaging and MR arthrography for diagnosis of recurrent tears in the postoperative meniscus. of the meniscus. 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. Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. . On the fat-supressed proton density-weighted coronal (17A) and axial (17B) images, notice the trapazoidal shaped bone bridge (arrow) placed in the tibial slot with menscal allograft attached at the anterior and posterior roots. The meniscus root plays an essential role in maintaining the circumferential hoop tension and preventing meniscal displacement. The example above illustrates marked degenerative changes caused by loss of meniscal function. Controlling Blood Pressure During Pregnancy Could Lower Dementia Risk, Researchers Address HIV Treatment Gap Among Underserved Population, HHS Announces Reorganization of Office for Civil Rights, FDA Adopts Flu-Like Plan for an Annual COVID Vaccine. A displaced longitudinal tear is a "bucket handle" tear. 2. 17. The patient underwent partial medial meniscectomy and ACL reconstruction. collapse and widening of the medial joint space (Figure 7). The MRI revealed a longitudinal tear in the posterior horn of the lateral meniscus. Conventional MRI is useful for evaluation of posterior root morphology at the tibial tunnel fixation site, meniscal extrusion and articular cartilage. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 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 . of these meniscal variants is the discoid lateral meniscus, and the include hypoplastic menisci, absent menisci, anomalous insertion of the 70 year-old female with history of medial meniscus posterior horn radial tear. discoid lateral meniscus is a relatively uncommon developmental variant Skeletal radiology. When bilateral, they are usually symmetric. noted to be diminutive, with the posterior horn measuring 7 mm to 8 mm. In the above case there is no gross chondral defect although the articular cartilage is noticeably thinner compared to the baseline study despite the patients young age. The prevalence of a medial discoid meniscus in patients with AIMM 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. Intact meniscal roots. proximal medial tibia was convex and the distal medial femoral condyle They divide the meniscus into superior and inferior halves (Fig. no financial relationships to ineligible companies to disclose. Heron, D, Bonnard C, Moraine C,Toutain A. Agenesis of cruciate Disadvantages include patient discomfort, increased cost, physician time needed for the procedure and radiation exposure during fluoroscopy. pivoting). Discoid meniscus in children: Magnetic resonance imaging characteristics. 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. Sagittal proton density-weighted image (9A) demonstrates no high signal abnormality. ligament, and the posterior horn may translate or rotate due to A tear of the anterior horn of the lateral meniscus is damage to the front part of one of the two structures that act as shock absorbers between the thigh bone and the lower leg, explains The Steadman Clinic. Dr. Diduch, Associate Professor, Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA, is Editor of Sports Medicine Reports. The Wrisberg variant may present with a Tachibana Y, Yamazaki Y, Ninomiya S. Discoid medial meniscus. Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation. This injury is biomechanically comparable to a total meniscectomy, leading to compromised hoop stressesresulting in decreased tibiofemoral contact area and increased contact pressures in the involved compartment.These changes are detrimental to the articular cartilage and . A tear of the meniscal root means the tear is near where it attaches to the bone, usually far in the back. Meniscal root tears are a form of radial tear that involves the central attachment of the meniscus (12a). Posterior meniscal root repairs: outcomes of an anatomic transtibial pull-out technique. On MRI, they resemble radial tears, with a linear cleft of abnormal signal seen at the free edge. Partial meniscectomy is by far the most common procedure. While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. When evaluating a portion of the meniscus that is in a different location than the repair, criteria for evaluating a virgin meniscus may be used for that area. In these cases, MR arthrography may provide additional diagnostic utility. 4). 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 [. This arises from the posterior horn of the lateral meniscus and attaches to the lateral aspect of the medial femoral condyle. 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. Radial tears comprise approximately 15 % of tears in some surgical series [. Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. The superior, middle and inferior geniculate arteries are the main vascular supply to the menisci. This scan showed a radial MMT. Complex or deep radial tears were found in three of five cases of lateral meniscus extrusion and normal root. Br Med Bull. MRI c spine / head jxn - they can have stenosis of foramen magnum . 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). mesenchymal mass that differentiates into the tibia, femur, and 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"}. Normal course and intensity of both cruciate ligaments. The shape of the meniscus is formed at the eighth week of Again, this emphasizes the importance of accurate history, prior imaging and operative reports. varus deformity (Figure 3). One of the most frequent indications for arthroscopic knee surgery is a meniscal tear.1 It is estimated that 1 million meniscus surgeries are performed in the U.S. annually with 4 billion dollars in associated direct medical expenditures.2 Meniscal surgeries include partial meniscectomy, meniscal repair and meniscal replacement. Weight-bearing knee X-rays showed a 50 % narrowing in the medial compartment. 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. The posterior root lies anterior to the posterior cruciate ligament. meniscus are not uncommon; they include an anomalous insertion of the joint: Morphologic changes and their potential role in childhood Discoid lateral meniscus was originally believed to result from an 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. It is usually seen near the lateral meniscus central attachment site. Grade 3 is a true meniscus tear and an arthroscope is close to 100 percent accurate in diagnosing this tear. Considered a feature of knee osteoarthritis. 2012;20(10):2098-103. the example shown (Figures 1 and 2), the entire medial meniscus is Both horns of the medial meniscus are triangular with sharp points. It can be divided into five segments: anterior horn, anterior, middle and posterior segments, and posterior horn. The avulsed anterior horn of the lateral meniscus is flipped over and situated above the posterior horn. 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. The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. discoid meniscus, although discoid medial menisci can occur much less Dr. Michael Gabor answered Diagnostic Radiology 35 years experience No,: It doesn't sound like a bucket handle tear insertion of the medial meniscus (AIMM) has been described, and it is A 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. {"url":"/signup-modal-props.json?lang=us"}, El-Feky M, Flipped meniscus - anterior horn lateral meniscus. is affected. Kim SJ, Choi CH. signal fluid cleft interposed between the posterior horn and the capsule that this rare condition is also clinically asymptomatic. Otherwise, the increased vascularity in children has sometimes led to false-positive reading of a meniscus tear. (1A) Proton density-weighted, (1B) T2-weighted, and (1C) fat-suppressed T1-weighted MR arthrographic sagittal images are provided. A meniscus is a crescent-shaped fibrocartilaginous structure that You have reached your article limit for the month. On the sagittal proton density-weighted image (11A), signal contacts the tibial surface. This mesenchymal One important reason for such discrepancies is a failure to understand the transverse geniculate ligament of the knee (TGL). At the time the case was submitted for publication Mostafa El-Feky had no recorded disclosures.