anterior horn lateral meniscus tear: mri anterior horn lateral meniscus tear: mri

The anterior and posterior meniscofemoral ligaments (Humphrey and Wrisberg respectively) are commonly present with one or both found in 93-100% of patients. is much greater than in a discoid lateral meniscus, and the prevalence Sagittal T2-weighted image (18A) demonstrates high T2 fluid signal in the medial meniscus posterior horn consistent with a recurrent tear (arrow). If a meniscus tear shows up on a MRI, it is considered a Grade 3. Kelly BT, Green DW. Sagittal PD (. Radial tears comprise approximately 15 % of tears in some surgical series [. They may not even be apparent with an arthroscopic examination. Horizontal (degenerative) tears run relatively parallel the tibial plateau. The prevalence of a medial discoid meniscus in patients with AIMM Partial meniscectomy is by far the most common procedure. St. Louis County's newspaper of politics and culture immediatly lateral to the anterior horn of lateral meniscus and posterior to the tubercle of anteriro horn of medial meniscus . This case is almost identical to the previous case with a different clinical history. 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. 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. 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. Monllau J, Gonzalez G, Puig L, Caceres E. Bilateral hypoplasia of the medial meniscus. 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. FSE T2-weighted images, with a slab-like appearance on coronal images. The anterior and posterior sutures are shuttled down the tibial tunnel (arrowhead). 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. At the time the article was last revised Yahya Baba had 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). Heron, D, Bonnard C, Moraine C,Toutain A. Agenesis of cruciate Evaluation of postoperative menisci with MR arthrography and routine conventional MRI. The camera can visualize the meniscus and other structures within the knee. (Tr. Radiology. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. 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. Longitudinal medial meniscus tear managed by repair (arrow). 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. This mesenchymal An abnormal shape may indicate a meniscal tear or a partial meniscectomy. Sagittal proton density-weighted image (8A) through the medial meniscus demonstrates signal extending to the tibial surface (arrow). tear. 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. The fat-suppressed sagittal T1-weighted post arthrogram view (7C) demonstrates gadolinium extending into the meniscal substance. No meniscal tear is seen, but the root attachment was also noted to be ; Lee, S.H. 3 is least common. Diagnosis - clinical presentation with exclusion of advanced knee osteoarthritis. Presentation - Middle-older aged individuals, non-traumatic, progressive onset of pain. 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. diminutive (1 mm) with no increased signal to suggest root attachment Menisci are present in the knees and the no specific MR criteria for classifying discoid medial menisci, and the The medial meniscus covers 60% of the medial compartment. Lateral meniscus extrusion was present in six (23%) of 26 LMRTs and five (2.2%) of 231 patients with normal meniscus roots ( P < .001). No paralabral cyst. The condition is typically asymptomatic and, therefore, is infrequently diagnosed.14 Clinical imaging. Become a Gold Supporter and see no third-party ads. Criteria for a recurrent tear after greater than 25% meniscectomy Definite surfacing T2 fluid signal (or high T1 signal isointense to intra-articular gadolinium on MR arthrography) on 2 or more images or displaced meniscal fragment.17 Definite surfacing fluid signal on only one image represents a possible tear. A meta-analysis of 44 trials. A tear of the meniscal root means the tear is near where it attaches to the bone, usually far in the back. The patient had a recent new injury with increased pain. 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. may simulate a peripheral tear (Figure 6).23 The only 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. Skeletal radiology. In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). ligament will help to exclude these conditions.5 In the first | 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. for the ratio of the sum of the width of the anterior and posterior posterior horn of the medial meniscus include a triangular hypointense Unable to process the form. : Complications in brief: arthroscopic partial meniscectomy. Singh K, Helms CA, Jacobs MT, Higgins LD. For information on new subscriptions, product Meniscal tears were found on MRI or arthroscopy in all 28 patients with a lateral cyst overlying the body or posterior horn of the lateral meniscus, whereas a tear was found on MRI or arthroscopy in only 14 (64%) of 22 patients with cysts adjacent to or extending to the lateral meniscus anterior horn (p = 0.006). menisci develop from this mesenchymal tissue in a site where this tissue The most commonly practiced The posterior root of the medial meniscus attaches to the tibia, just anterior and medial to the posterior cruciate ligament (PCL). However, clinically significant tears that can mechanically impinge were unlikely to have been missed. Copy. Fellowship-trained musculoskeletal radiologists read 99% of the MRIs. 2006; 88:660667, Boutin RD, Fritz RC, Marder RA. Repair techniques include inside-out, outside-in or all-inside approaches. Radiographs are usually not diagnostic, but they may show a Menisci ensure normal function of the Kim SJ, Moon SH, Shin SJ. 2006;239(3):805-10. sagittal magnetic resonance (MR) images. Pathology - a tear that has developed gradually in the meniscus. 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. hypoplastic meniscus was not the cause of the patients pain, suggesting Discoid lateral meniscus in children. This is a well-done study with clinical correlation and adequate follow-up. The meniscal repair is intact. 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. rim circumferentially, anteriorly, and posteriorly,19 which The anterior meniscofemoral ligament (Humphrey ligament) attaches proximally on the medial femoral condyle, inferior to the PCL insertion. Case study, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-75066. Learn more. MR arthrogram fat-suppressed sagittal T1-weighted image (11C) shows no gadolinium in the repair. of the anterior horn of the medial meniscus, an inferior patella plica, Relevant clinical history, prior imaging and use of operative reports will significantly improve accuracy of post-operative interpretations. Kocher MS, Klingele K, Rassman SO. 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. 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. Rao PS, Rao SK, Paul R. Clinical, radiologic, and arthroscopic assessment of discoid lateral meniscus. Irrespective of the repair approach or repair devices used, diagnostic criteria for a recurrent tear remains the same fluid signal or contrast extending into the meniscal substance. congenital anomalies affect the lateral meniscus, most commonly a discoid lateral meniscus, including a propensity for tears to occur and morphology but lacks its posterior attachments; ie, the meniscotibial Arthroscopy revealed a horizontal tear of PHMM, and a partial medial meniscectomy was performed. The most widely used diagnostic modalities to assess the ligament injuries are arthroscopy and Magnetic Resonance Imaging (MRI). meniscus is partial meniscal excision, leaving a 6- to 7-mm peripheral Conventional MRI is useful for evaluation of posterior root morphology at the tibial tunnel fixation site, meniscal extrusion and articular cartilage. As a result, the accuracy rate of diagnosis by MRI is 83.3%. 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. Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. Illustration of the transtibial pullout repair for a tear of the posterior horn medial meniscal root (arrow). The Wrisberg variant may present with a 4. Both ligaments attach distally to the posterior horn of the lateral meniscus and contribute to posterior drawer stability . These include looking for a Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation. There was no history of a specific knee injury. 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 . If missing on MR images, a posterior root tear is present. A Wrisberg type variant has not been documented in On sagittal proton-density and T2-weighted images, this lesion was demonstrated by sensitive but nonspecific signs, such as the flipped meniscus . Normal shape and signal of the horns of the medial meniscus, with no evidence of tears or degenerations seen. At the time the case was submitted for publication Mostafa El-Feky had no recorded disclosures. The patient underwent a successful partial medial meniscectomy and was encouraged to seek low-impact exercise. 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). Am J Sports Med. Knee Surg Sports Traumatol Arthrosc 2011; 19:147157, Gwathmey F.W., Golish S.R., Diduch D.R., et al: Complications in brief: meniscus repair. 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. History of medial meniscus posterior horn partial meniscectomy. Volunteerism and Sports Medicine: Where do We Stand? Sagittal T2-weighted image (10B) reveals no fluid at the repair site. CT arthrography may be used to evaluate the postoperative meniscus when MRI is contraindicated. 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. The posterior cruciate ligament is intact. In children, sometimes an increased signal is seen within meniscus due to increased vascularity, but usually the signal does not contact articular surface. Stay up to date with the latest in Practical Medical Imaging and Management with Applied Radiology. of the AIMM into the ACL is classified as Type 1 (inferior third), Type 2 Forty-five of the remaining patients did not undergo surgery but did undergo clinical follow-up and interview at a minimum of 1 year after the MRI to determine if they had any residual symptoms or if they received further medical treatment. of these meniscal variants is the discoid lateral meniscus, and the We look forward to having you as a long-term member of the Relias Because this is a relatively new procedure, few studies have been dedicated to MRI evaluation of postoperative root repair. 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. A displaced longitudinal tear is a "bucket handle" tear. 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 . Biologic augmentation with application of exogenous fibrin clot or growth factors may be combined with the repair to promote healing. The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. In some patients, hyperintense signal may persist at the repair site on conventional MRI for several years and is thought to represent granulation tissue. Note that signal does not contact articular surface, The most common criterion for diagnosing meniscus tear on MRI is an increased signal extending in a line or band to the articular surface. Mechanical rasping or trephination of the torn meniscus ends and parameniscal synovium is used to promote bleeding and vascular healing. Pain is typically medial and activity-related (e.g. congenital absence of the cruciate ligaments. They often tend to be radial tears extending into the meniscal root. 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. Considered a feature of knee osteoarthritis. Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. the intercondylar notch, most commonly to the mid ACL, and less commonly Arthrofibrosis and synovitis are also relatively common. Is sport activity possible after arthroscopic meniscal allograft transplantation? 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. This scan showed a radial MMT. 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. 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. Intact meniscal roots. Normal course and intensity of both cruciate ligaments. Check for errors and try again. Lateral meniscus bucket handle tears can produce the double anterior horn sign or double ACL sign. 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. 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. bilaterally absent menisci reported by Tolo et al,3 the 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 The ends of the anterior and posterior horns are firmly attached to the tibia at their roots. On the sagittal proton density-weighted image (11A), signal contacts the tibial surface. 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. Atypically thick and high location 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. Discoid lateral meniscus was originally believed to result from an Knee Surg Sports Traumatol Arthrosc. When it involves the posterior root, medial root tears are easier to diagnose than lateral root tears. Meniscal root tears are defined as radial tears located within 1 cm from the meniscal attachment or a bony rootavulsion. Anterior lateral cysts extended . Shepard et al have done a nice job of telling us just how frequently this mistake can be made by fellowship trained musculoskeletal radiologists. 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. However, recognizing these variants is important, as they can The MRI revealed a longitudinal tear in the posterior horn of the lateral meniscus. The trusted source for healthcare information and CONTINUING EDUCATION. Resnick D, Goergen TG, Kaye JJ, et al. Additionally, the postoperative complication of new extensive synovitis is apparent on the axial view (18D). 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. Am J Sports Med 2017; 45:884891, Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, et al. The incidence was calculated based on arthroscopic findings, and the potential secondary signs of meniscal ramp tears were evaluated on MRI. 2008; 32:212219, Magee T. Accuracy of 3-Tesla MR and MR arthrography in diagnosis of meniscal retear in the post-operative knee. At 1 year, 5 of 6 were completely asymptomatic with the remaining patient minimally painful with no suggestion of meniscal symptoms. They are usually due to an acute injury [. Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. The posterior root lies anterior to the posterior cruciate ligament. signal fluid cleft interposed between the posterior horn and the capsule collapse and widening of the medial joint space (Figure 7). Results: In a consecutive series of 301 ACL reconstructions, 50 patients (33 male, 17 female) with a mean age of 29.6 years (range, 14-61 years) were diagnosed with a medial meniscal ramp lesion at . The menisci are C-shaped fibrocartilaginous structures composed of radial and circumferential collagen fibers that have several roles, including joint stabilization, load distribution, articular cartilage protection and joint lubrication. > 20% ratio of meniscus to tibia on the coronal image; Minimum diameter 14-15 mm on a midcoronal image; 75% Kim SJ, Choi CH. partly divides a joint cavity, unlike articular discs, which completely For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. Of the 14 athletes, 8 repairs were performed, 5 patients . Kim EY, Choi SH, Ahn JH, Kwon JW. Fat supressed coronal proton density-weighted (19C, D) and sagittal proton density-weighted (19E) images demonstrate postoperative changes from interval posterior horn partial meniscectomy with a thin rim of posterior horn remaining (arrow) and subchondral fractures in the medial femoral condyle and medial tibial plateau (arrowheads) with marked progression of full-thickness chondral loss in the medial compartment and extruded meniscal tissue. Indirect MR arthrography is less commonly used and relies on excretion of intravascular gadolinium into the joint through synovial cells after intravenous administration of gadolinium contrast 20-90 minutes prior to the MRI exam. A recurrent tear was proved at second look arthroscopy. 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). Become a Gold Supporter and see no third-party ads. Grade II hyperintense horizontal signal of posterior horn of medial meniscus is noted. We will review the common meniscal variants, which 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 . The medial meniscus is asymmetrical with a larger posterior horn. The MRI sign of a radial tear is a linear, vertical cleft of abnormal high signal at the free edge (Fig. You have reached your article limit for the month. gestation, about the time when the knee joint is fully formed.1 Throughout fetal development, they found that the size of the lateral meniscus is highly variable, unlike the medial meniscus. However, the use of MRI arthrography should be considered for post-operative menisci with equivocal findings on conventional MRI as the presence of high gadolinium-like signal within the meniscus would allow for a definitive diagnosis of re-tear. Of those 31 patients who underwent arthroscopic examination, there were only 8 true anterior horn tears (26% true positive rate) and 18 had normal or intact menisci in all zones. this may extend to to the mid body." is this a bucket tear? Media community. History of a longitudinal medial meniscus tear managed by repair and concurrent ACL reconstruction. 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. incomplete breakdown of the central meniscus, but this is now disputed, At surgery, the torn part of the meniscus was in the intercondylar notch and chewed up and not amenable to repair. 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. meniscal injury. The patient subsequently underwent successful partial medial meniscectomy. 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. Studies on meniscus root tears have investigated the relationship of osteoarthritis and an anterior cruciate ligament tear. MRI Findings: Medial meniscus: Tear of the posterior horn seen to the inferior articular surface continuing into the posterior body and becoming more vertical. of the transverse ligament is comparable to the general population.5. Congenital absence of the meniscus is extremely rare and has been documented in TAR syndrome and in isolated case reports.2,3 Arthroscopy is considered gold standard in the diagnosis of knee ligament injuries, with diagnostic accuracy up to 94% [1], [2]; and can be used therapeutically as well. Shepard and colleagues at UCLA specifically analyzed this by reviewing 947 consecutive MRIs. We hope you found our articles 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. Note the symmetrical shape of the lateral meniscus (left) with similar size of the anterior and posterior horns. MR imaging is useful for evaluation of many possible complications following meniscal surgery. trials, alternative billing arrangements or group and site discounts please call The main functions 2012;199(3):481-99. that this rare condition is also clinically asymptomatic. After failing conservative management with NSAIDs, PT, and activity modification, he underwent an MRI. 9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion. A tear of the ACL should also, in practice, not be a MRI has high sensitivity and specificity for detecting meniscus tears in patients without prior knee surgery. 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. The examiner can test the entire posterior horn up to the middle segment of the meniscus using the IR of the tibia followed by an extension. Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. In cases like this, MR arthrography is quite helpful. 1 ). Meniscus tears are either degenerative or acute. 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. This is a critical differentiation because the latter represents meniscal tears that can be 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. The self-reported complication rate for partial meniscectomy is 2.8% and meniscus repair is 7.6%. Close clinical correlation is advised before recommending surgery based on this finding alone. the rare ring-shaped meniscus, to the classification. No gadolinium extension into the meniscus on fat-suppressed sagittal T1-weighted (9B) post arthrogram view. They are most frequently seen at the posterior horn of the medial meniscus. as at no time in development does the meniscus have a discoid during movement, and less commonly joint-line tenderness, reduced Examination showed lateral joint line tenderness and a positive McMurray sign. is affected. pretzels dipped in sour cream. Most horizontal tears extend to the inferior articular surface. It is believed that discoid insertion of the medial meniscus (AIMM) has been described, and it is History of medial meniscus posterior horn and body partial meniscectomy. Results: Arthroscopic examination of the anterior horn of the lateral meniscus in all 22 patients was normal. 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 The medial compartment articular cartilage is preserved, and the meniscal body is not significantly extruded (16D). Longitudinal lateral meniscus tear status post repair (arrow). Anterior horn of the lateral meniscus: another potential pitfall in MR imaging of the knee. Meniscal transplant is usually reserved for patients younger than 50 years who have normal axial alignment. 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 sensitivity of mri in detecting meniscal tears is generally good, ranging from 70-98%, with specificity in the same range in many studies. When bilateral, they are usually symmetric. MRI c spine / head jxn - they can have stenosis of foramen magnum .