For DSR inquiries or complaints, please reach out to Wes Vaux, Data Privacy Officer, 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). Lateral meniscus extrusion was present in six (23%) of 26 LMRTs and five (2.2%) of 231 patients with normal meniscus roots ( P < .001). These include looking for a Generally, Type 1 is most common, and type They may not even be apparent with an arthroscopic examination. Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. A classification system developed by the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine [, Longitudinal-vertical tear. 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. incomplete breakdown of the central meniscus, but this is now disputed, Posteroinferior displacement of the meniscal tissue (arrowheads) is also diagnostic of recurrent tear. 2008;191(1):81-5. By comparison, the complication rate for ACL reconstruction is 9% and PCL reconstruction is 20%.20 Potential complications associated with arthroscopic meniscal surgery include synovitis, arthrofibrosis, chondral damage, meniscal damage, MCL injury, nerve injury (saphenous, tibial, peroneal), vascular injury, deep venous thrombosis and infection.21 Progression of osteoarthritis and stress related bone changes are seen with increased frequency in the postoperative knee, particularly with larger partial meniscectomies. Radial or oblique tear congurations close to or within the meniscus . 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. Cho JM, Suh JS, Na JB, et al. They were first described by M J Pagnaniet al. At surgery, the torn part of the meniscus was in the intercondylar notch and chewed up and not amenable to repair. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. Development of the menisci of the human knee 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. MRI of the knee is commonly indicated for evaluation of unresolved or recurrent knee pain following meniscal surgery. 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. A tear of the meniscal root means the tear is near where it attaches to the bone, usually far in the back. What is your diagnosis? 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 [. Discoid lateral meniscus in children. There was no evidence of meniscal extrusion or a meniscal ghost sign (Fig. Best assessed on T2 weighted sequences. 800-688-2421. Kijowski et al. diminutive (1 mm) with no increased signal to suggest root attachment Meniscal disorders: Normal, discoid, and cysts. Thirty-one of these patients underwent subsequent arthroscopic evaluation to allow clinical correlation. 2020;49(1):42-49. Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. 1. 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. History of medial meniscus posterior horn partial meniscectomy. 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 clinical significance of anterior horn meniscal tears diagnosed on magnetic resonance images. 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. Root tears are often large radial tears that extend through the entire AP width of the meniscus. The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. Medial meniscus bucket handle tears can result in a double PCL sign. Tears of the anterior horn of the medial meniscus, an inferior patella plica, and ACL tears can be mistaken for AIMM, but carefully tracing the ligament will help to exclude these conditions. Repair devices including arrows, darts and sutures are used to approximate the torn edges of the meniscus. Meniscal root tear. Normal Youderian A, Chmell S, Stull MA. Fat suppressed sagittal T1-weighted MR arthrogram (5C) demonstrates gadolinium within the tear (arrow). Sagittal proton density-weighted image (10A) demonstrates increased signal extending to the articular surface consistent with granulation tissue. Meniscal root tears are defined as radial tears located within 1 cm from the meniscal attachment or a bony rootavulsion. Magnetic Resonance Imaging Arthroscopy Orthodontic Extrusion Anterior Cruciate Ligament Reconstruction Arthroscopes Suture Anchors Tissue Culture Techniques Tissue Engineering Injections, Intra-Articular Range of Motion, Articular Arthrography Hardness Tests Orthopedic Procedures Check for errors and try again. Grade 3 is a true meniscus tear and an arthroscope is close to 100 percent accurate in diagnosing this tear. 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 Kocher MS, Klingele K, Rassman SO. Case study, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-75066. 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 example above demonstrates the importance of baseline MRI comparison when evaluating the postoperative meniscus. Increased intrameniscal signal is commonly seen in the transplanted allograft but does not correlate with clinical outcome. (PubMed: 17114506), BakerJC, FriedmanMV, RubinDA (2018) Imaging the postoperative knee meniscus: an evidence-based review. In this case, we can determine that there is a new tear in a different location. 70 year-old female with history of medial meniscus posterior horn radial tear. Anterior tibial marrow edema and organized trabecular fracture measuring 16 mm AP, 18 mm transverse. 5. Menisci ensure normal function of the The posterior cruciate ligament is intact. However, recognizing these variants is important, as they can instance, tears of the lateral aspect of the anterior horn of the Exam showed a mild effusion and medial joint line tenderness. 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 most frequent symptom is pain that usually begins with a minor of the distal femur and proximal tibia, and in the case report of An abnormal shape may indicate a meniscal tear or a partial meniscectomy. MRI appearance of Wrisberg variant of discoid lateral meniscus. 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. 2059-2066, Kinsella S.D., and Carey J.L. that this rare condition is also clinically asymptomatic. Monllau J, Gonzalez G, Puig L, Caceres E. Bilateral hypoplasia of the medial meniscus. noted to be diminutive, with the posterior horn measuring 7 mm to 8 mm. Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. There was no history of a specific knee injury. Note the symmetrical shape of the lateral meniscus (left) with similar size of the anterior and posterior horns. Kim SJ, Moon SH, Shin SJ. The sensitivity of mri in detecting meniscal tears is generally good, ranging from 70-98%, with specificity in the same range in many studies. an adult), and approximately twice the size of the anterior horn on Type MR arthrogram fat-suppressed sagittal T1-weighted image (11C) shows no gadolinium in the repair. Get unlimited access to our full publication and article library. 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. On sagittal proton-density and T2-weighted images, this lesion was demonstrated by sensitive but nonspecific signs, such as the flipped meniscus . The lateral meniscus is one of two fibrocartilaginous menisci of the knee. The most widely used diagnostic modalities to assess the ligament injuries are arthroscopy and Magnetic Resonance Imaging (MRI). menisci (Figure 8). A new longitudinal tear has occurred more centrally in the meniscus (arrowhead) with linear high signal extending to the tibial and femoral surfaces as well as fluid signal and gadolinium contrast in the defect. Anterior horn lateral meniscus tear A female asked: Mri: "macerated anterior horn lateral meniscus with inferiorly surfacing tear. posterior fascicles and meniscotibial ligament are absent and a high The posterior root of the medial meniscus attaches to the tibia, just anterior and medial to the posterior cruciate ligament (PCL). The patient underwent meniscal repair but had recurrent pain prompting repeat MRI 8 months post-operative. Normal course and intensity of both cruciate ligaments. Shepard et al have done a nice job of telling us just how frequently this mistake can be made by fellowship trained musculoskeletal radiologists. (Tr. The patient underwent an all-inside lateral meniscus repair. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. 2002; 222:421429, Ciliz D, Ciliz A, Elverici E, Sakman B, Yuksel E, Akbulut O. Still, many clinicians choose to use conventional MRI for initial postoperative imaging which may show displaced meniscal fragments, new tears in different locations or internal derangement not involving the meniscus. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. ADVERTISEMENT: Supporters see fewer/no ads. normal knee. The lateral . congenital anomalies affect the lateral meniscus, most commonly a On examination, there was marked medial joint line tenderness and a large effusion. The symptoms Methods Eighteen patients who had arthroscopically confirmed partial MMPRTs were included. 2013;106(1):91-115. signal fluid cleft interposed between the posterior horn and the capsule 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. Kelly BT, Green DW. Associated anomalies in a discoid medial According to one source, they are thought to account for ~10% of all arthroscopic meniscectomies 5. Diagnosis of recurrent meniscal tears: prospective evaluation of conventional MR imaging, indirect MR arthrography, and direct MR arthrography. 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. 2006; 187:W565568. 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. 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. Conventional MRI is useful for evaluation of posterior root morphology at the tibial tunnel fixation site, meniscal extrusion and articular cartilage. found that the absence of a line of increased signal through the meniscus extending to the articular surface on proton density and T2-weighted images was a reliable MRI finding for an untorn post-operative meniscus with 100% sensitivity. this may extend to to the mid body." is this a bucket tear? ligament will help to exclude these conditions.5 In the first 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. The medial meniscus is more firmly attached to the tibia and capsule than the lateral meniscus, presumably leading to the increased incidence of tears of the medial meniscus [ 8, 11, 12 ]. Unable to process the form. Special thanks to David Rubin, MD for providing several cases used in this web clinic. 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. If missing on MR images, a posterior root tear is present. horns to the meniscal diameter on a sagittal slice that shows a maximum also found various MRI characteristics highly specific for detection of a recurrent tear including a line of intermediate-to-high signal or high signal through the meniscus extending into the articular surface on T2-weighted images with 95.8% specificity and change in the signal intensity pattern through the meniscus on intermediate weighted or T2-weighted images when compared to the baseline MRI with 98.2% specificity. Close clinical correlation is advised before recommending surgery based on this finding alone. The medial meniscus covers 60% of the medial compartment. 6. Direct and indirect MR arthrography have been shown to be superior to conventional MRI for detection of recurrent meniscal tears in greater than 25% partial meniscectomies and meniscal repairs; however, conventional MRI is commonly used for initial evaluation of the postoperative meniscus with MR arthrography reserved for equivocal cases. By continuing to use our site, you consent to the use of cookies outlined in our Privacy Policy. The prevalence of a medial discoid meniscus in patients with AIMM Dickhaut SC, DeLee JC. AJR Am J Roentgenol. 2006; 88:660667, Boutin RD, Fritz RC, Marder RA. Tibial meniscal dynamics using three-dimensional reconstruction of magnetic resonance images. Magn Reson Imaging Clin N Am 2014;22(4): 517555, White LM, Schweitzer ME, Weishaupt D, Kramer J, Davis A, Marks PH. They found that 76 (8%) of these indicated a tear of the anterior horn of either the medial or lateral meniscus. Atypically thick and high location Stay up to date with the latest in Practical Medical Imaging and Management with Applied Radiology. An intact meniscal repair was confirmed at second look arthroscopy. Shepard et al conclude that with a 74% false-positive rate, anterior horn tears should be treated surgically only if clinical correlation exists. Pinar H, Akseki D, Karaoglan O, et al. Most horizontal tears extend to the inferior articular surface. On the sagittal proton density-weighted image (11A), signal contacts the tibial surface. Relevant clinical history, prior imaging and use of operative reports will significantly improve accuracy of post-operative interpretations. He presented after a few months with symptoms of instability. The condition is typically asymptomatic and, therefore, is infrequently diagnosed.14 Unable to process the form. 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. 2. What causes abnormal mobility in the medial meniscus? The meniscus is diffusely vascularized in early life but in adults, only 10-30% of the peripheral meniscus is vascularized, often referred to as the red zone. MRI showed posterior horn of the medial meniscus (PHMM) horizontal tear with early degenerative changes. the posterior horn is usually much larger than the anterior horn (the A Wrisberg type variant has not been documented in Surgical Outcomes Lysholm Score pivoting). 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. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. may simulate a peripheral tear (Figure 6).23 The only 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 Longitudinal medial meniscus tear managed by repair (arrow). 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. Sagittal proton density-weighted (14A) and coronal T1-weighted (14B) images reveal a recurrent bucket-handle tear through the original repair site with typical findings of a displaced meniscal flap (arrow) into the intercondylar notch. 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. 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. Vertical flap (oblique, flap, parrots beak) tears are unstable tears and occur in younger patients. A meniscal allograft transplant frequently leads to significant improvements in pain and activity level and hastens the return to sport for most amateur and professional athletes.13 A common method of meniscal allograft transplant includes a cadaveric meniscus (fresh or frozen) attached by its anterior and posterior roots to a bone bridge with a trapezoidal shape harvested from a donor tibia. 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. The shape of the meniscus is formed at the eighth week of {"url":"/signup-modal-props.json?lang=us"}, Weerakkody Y, Baba Y, Knipe H, et al. 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. They are usually due to an acute injury [. Tachibana Y, Yamazaki Y, Ninomiya S. Discoid medial meniscus. 2012;20(10):2098-103. Materials and methods . You can use Radiopaedia cases in a variety of ways to help you learn and teach. AJR Am J Roentgenol 2009;193:515-523. 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. Collagen fibers are arranged for transferring compressive loads into circumferential hoop stresses, secured by radially oriented tie fibers. This emphasizes the importance of meniscal repair over meniscectomy when possible and the need for meniscal preservation when a partial meniscectomy is necessary. (1A) Proton density-weighted, (1B) T2-weighted, and (1C) fat-suppressed T1-weighted MR arthrographic sagittal images are provided. They are most frequently seen at the posterior horn of the medial meniscus. Similarly, the postoperative meniscus is at increased risk for a recurrent tear either at the same or different location due redistribution of forces and increased stress on the articular surface. (middle third), or Type 3 (superior third; intercondylar notch) (Figure This scan showed a radial MMT. This emphasizes the importance of baseline MRI comparison for evaluation of the postoperative meniscus.3. 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. 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. The aim of this study was to evaluate diagnostic values involved in conventional magnetic resonance imaging (MRI) features of MM posterior root tears (MMPRTs) and find other MRI-based findings in patients with partial MMPRTs. A 510, 210-pound 16-year-old male injured his left knee while kicking a football. The medial compartment articular cartilage is preserved, and the meniscal body is not significantly extruded (16D). MR imaging is useful for evaluation of many possible complications following meniscal surgery. 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 . Considered a feature of knee osteoarthritis. Lee, J.W. There is a medial and a lateral meniscus. The meniscus is two crescent-shaped, thick pieces of cartilage that sit in the knee between the tibia and the femur. What is a Lateral Meniscus Tear? 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"}. Discoid lateral meniscus and the frequency of meniscal tears. It is usually seen near the lateral meniscus central attachment site. Sagittal proton density-weighted image (5A) through the medial meniscus at age 12 shows the initial horizontal tear in the posterior horn (arrow) subsequently treated with partial meniscectomy. Check for errors and try again. Skeletal radiology. . rim circumferentially, anteriorly, and posteriorly,19 which How I Diagnose Meniscal Tears on Knee MRI. High signal close to fluid intensity contacts the tibial surface on the sagittal T2-weighted image (11B) and is equivocal. CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. Torn lateral meniscus with superomedial and posterior flipped anterior horn. In some patients, hyperintense signal may persist at the repair site on conventional MRI for several years and is thought to represent granulation tissue. Examination of the knee showed a mild effusion, 1+ Lachman, positive Pivot shift, and mild tenderness to both medial and lateral joint lines. Objectives: Low-field MRI at 0.55 Tesla (T) with deep learning image reconstruction has recently become commercially available. Arthrofibrosis and synovitis are also relatively common. Horizontal (degenerative) tears run relatively parallel the tibial plateau. sagittal magnetic resonance (MR) images. The anomalous insertion This case is almost identical to the previous case with a different clinical history. 2a, 2b, 2c). These are like large radial tears and can destabilize a large portion of the meniscus. Interested in Group Sales? Comparison of Postoperative Antibiotic Regimens for Complex Appendicitis: Is Two Days as Good as Five Days? 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. Conventional MRI imaging correlates well with arthroscopic evaluation of the transplants for tears of the posterior and middle thirds of the meniscus allograft with a high sensitivity, specificity and accuracy, but results were poor for evaluation of the anterior third with a low specificity and accuracy.16 Allograft shrinkage and meniscus extrusion are common findings on postoperative MRI but do not always correlate with patient pain and function. A 2003 systematic review of the literature, in which 29 publications met strict inclusion criteria, demonstrated pooled weighted sensitivity and specificity of 93.3 % and 88.4 % for the medial meniscus and 79.3 % and 95.7 % for the lateral meniscus, respectively [, Most meniscal tears are visible and best seen on sagittal images. 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). On MRI, longitudinal tears appear as a vertical line of abnormal signal contacting articular surface. 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 Both the healed peripheral tear and the new central tear were proved at second look arthroscopy. Variations in meniscofemoral ligaments at anatomical study and MR imaging. The congenitally absent meniscus appears to influence the development It splits into two bands at the PCL, named Humphry(anterior to the PCL) and Wrisberg (posterior to the PCL). Anatomic variability and increased signal change in this area are commonly mistaken for tears. 3: The Wrisberg variant, where the meniscus may have a normal Dr. Michael Gabor answered Diagnostic Radiology 35 years experience No,: It doesn't sound like a bucket handle tear 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. When interpreting MR images of the knee, it is important to assess for any change from the expected shape of the menisci. Kim EY, Choi SH, Ahn JH, Kwon JW.
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