of the AIMM into the ACL is classified as Type 1 (inferior third), Type 2 It is often explained by fibers of the anterior cruciate ligament and the covering synovium . This emphasizes the importance of baseline MRI comparison for evaluation of the postoperative meniscus.3. The reported prevalence is 0.06% to 0.3%.25 They maintain a relatively constant distance from the periphery of the meniscus [. FSE T2-weighted images, with a slab-like appearance on coronal images. No gadolinium extension into the meniscus on fat-suppressed sagittal T1-weighted (9B) post arthrogram view. The discoid lateral-meniscus syndrome. The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). History of medial meniscus posterior horn partial meniscectomy. discoid lateral meniscus, including a propensity for tears to occur and Singh K, Helms CA, Jacobs MT, Higgins LD. 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. as at no time in development does the meniscus have a discoid The patient underwent meniscal repair but had recurrent pain prompting repeat MRI 8 months post-operative. Symptomatic anomalous insertion of the medial meniscus. MR imaging and MR arthrography for diagnosis of recurrent tears in the postoperative meniscus. While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. 2008;191(1):81-5. What is a Grade 3 meniscus tear? 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. 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 . 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. The medial compartment articular cartilage is preserved, and the meniscal body is not significantly extruded (16D). meniscal diameter. 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. 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. 1991;7(3):297-300. Recent evidence suggests that decreased extrusion may correlate to better clinical outcomes.18. Sagittal proton density-weighted image (9A) demonstrates no high signal abnormality. incomplete breakdown of the central meniscus, but this is now disputed, Mechanical rasping or trephination of the torn meniscus ends and parameniscal synovium is used to promote bleeding and vascular healing. 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. 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. Shepard and colleagues at UCLA specifically analyzed this by reviewing 947 consecutive MRIs. What causes abnormal mobility in the medial meniscus? 3: The Wrisberg variant, where the meniscus may have a normal De Smet A. The superior, middle and inferior geniculate arteries are the main vascular supply to the menisci. reported.4. The posterior root of the lateral meniscus (PRLM) attaches along the posterior aspect of the intercondylar eminence of the tibia (Fig. 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. In To provide the highest quality clinical and technology services to customers and patients, in the spirit of continuous improvement and innovation. 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. was saddle shaped. Discoid lateral meniscus (DLM) is a common anatomic variant in the knee typically presented in young populations, with a greater incidence in the Asian population than in other populations. Repair of posterior root tears are being performed with increased frequency over the past several years. 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. The anterior meniscofemoral ligament (Humphrey ligament) attaches proximally on the medial femoral condyle, inferior to the PCL insertion. This article focuses on Congenital absence of the meniscus is extremely rare and has been documented in TAR syndrome and in isolated case reports.2,3 Clark CR, Ogden JA. Meniscus tears, indicated by MRI, are classified in three grades. Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. 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. Radiology. 2012;20(10):2098-103. 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. There are 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. treatment for stable complete or incomplete types of discoid lateral > 20% ratio of meniscus to tibia on the coronal image; Minimum diameter 14-15 mm on a midcoronal image; 75% Anomalous Meniscal tears are common and often associated with knee pain. 2002; 222:421429, Ciliz D, Ciliz A, Elverici E, Sakman B, Yuksel E, Akbulut O. A classification system developed by the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine [, Longitudinal-vertical tear. Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. be misinterpreted for more significant pathology on MRI. 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. least common is complete congenital absence of the menisci. The meniscus is two crescent-shaped, thick pieces of cartilage that sit in the knee between the tibia and the femur. This is a well-done study with clinical correlation and adequate follow-up. 2006;239(3):805-10. congenital anomalies affect the lateral meniscus, most commonly a There are 3 main types, according to the Watanabe classification:18. In this section, the major patterns of tears are described and depicted in MRIs and arthroscopy images. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. The posterior cruciate ligament is intact. However, this conjecture and others pre- highest.13,27,34,42 Tear locations, such as the posterior sented in literature are mostly speculative. Brody J, Lin H, Hulstyn M, Tung G. Lateral Meniscus Root Tear and Meniscus Extrusion with Anterior Cruciate Ligament Tear. These include looking for a When it involves the posterior root, medial root tears are easier to diagnose than lateral root tears. that this rare condition is also clinically asymptomatic. Thompson WO, Thaete FL, Fu FH, Dye SF. 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 . 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. Studies on meniscus root tears have investigated the relationship of osteoarthritis and an anterior cruciate ligament tear. bilaterally absent menisci reported by Tolo et al,3 the By continuing to use our site, you consent to the use of cookies outlined in our Privacy Policy. 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. American Board of Orthopaedic Surgery Practice of the Orthopaedic Surgeon: Part-II, certification examination case mix. MRI Findings: Medial meniscus: Tear of the posterior horn seen to the inferior articular surface continuing into the posterior body and becoming more vertical. 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. Extrusion is commonly seen following root repair. Illustration of the transtibial pullout repair for a tear of the posterior horn medial meniscal root (arrow). A previous study by De Smet et al. There Arthroscopy: The Journal of Arthroscopic & Related Surgery. Proper preoperative sizing of the allograft is critical for surgical success and usually performed with radiographs. 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. Neuschwander DC, Drez D Jr, Finney TP. 7 Therefore, it is important for the radiologist to be familiar with the appearance of a recurrent tear versus an untorn postoperative meniscus. Both horns of the medial meniscus are triangular with sharp points. (middle third), or Type 3 (superior third; intercondylar notch) (Figure Repair devices including arrows, darts and sutures are used to approximate the torn edges of the meniscus. Discoid lateral meniscus of the knee joint: Nature, mechanism, and operative treatment. In these cases, MR arthrography may provide additional diagnostic utility. An intact meniscal repair was confirmed at second look arthroscopy. Stay up to date with the latest in Practical Medical Imaging and Management with Applied Radiology. Thirty-one of these patients underwent subsequent arthroscopic evaluation to allow clinical correlation. of the anterior horn of the medial meniscus, an inferior patella plica, 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. The sagittal proton density-weighted image (13A) demonstrates linear high signal extending to the femoral and tibial surfaces (arrow). Congenital discoid cartilage. The lateral meniscus is produced by the varus tension and tibial IR. Comparison of Postoperative Antibiotic Regimens for Complex Appendicitis: Is Two Days as Good as Five Days? Objectives: Low-field MRI at 0.55 Tesla (T) with deep learning image reconstruction has recently become commercially available. Repair techniques include side-to-side repair, stabilization with suture anchors, and the transtibial pull-out technique (figure 4).12. of the distal femur and proximal tibia, and in the case report of joint, and they also protect the hyaline cartilage. Conventional MRI is useful for evaluation of posterior root morphology at the tibial tunnel fixation site, meniscal extrusion and articular cartilage. 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. Knee Surg Sports Traumatol Arthrosc. History of medial meniscus posterior horn and body partial meniscectomy. high fibula head and a widened lateral joint space.20 Several Thirty-one of these patients underwent subsequent arthroscopic evaluation to allow clinical correlation. Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window), Click to share on Google+ (Opens in new window), Posterior Instability and Labral Pathology, Imaging Evaluation of the Painful or Failed Shoulder Arthroplasty, Other Entities: PLRI, HO, Triceps, and Plica, MRI-Arthroscopy Correlations in the Overhead Athlete, Acetabular Fossa, Femoral Fovea, and the Ligamentum Teres. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. horns to the meniscal diameter on a sagittal slice that shows a maximum Both the healed peripheral tear and the new central tear were proved at second look arthroscopy. Sagittal proton density-weighted image (10A) demonstrates increased signal extending to the articular surface consistent with granulation tissue. Medial meniscus bucket handle tears can result in a double PCL sign. Copy. 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 . There was no evidence of meniscal extrusion or a meniscal ghost sign (Fig. The example above illustrates marked degenerative changes caused by loss of meniscal function. varus deformity (Figure 3). Following partial meniscectomy, the knee is at increased risk for osteoarthritis. Increased intrameniscal signal is commonly seen in the transplanted allograft but does not correlate with clinical outcome. patella or Hoffas fat pad, and should be fairly easily differentiated 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. ligaments are absent, most commonly the anterior cruciate ligament (ACL) In this case, we can determine that there is a new tear in a different location. Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. 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. Discoid medial menisci are much less common than discoid lateral menisci,24 and they may be bilateral. Klingele KE, Kocher MS, Hresko MT, et al. is in fact reducing the volume of the meniscus and restoring a normal 2006; 187:W565568. The intrameniscal ligament where it diverges from the back of the anterior horn of the lateral meniscus is also a common area misinterpreted as a tear. 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. 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. Tachibana Y, Yamazaki Y, Ninomiya S. Discoid medial meniscus. Tolo VT. Congenital absence of the menisci and cruciate ligaments of the knee: A case report. may simulate a peripheral tear (Figure 6).23 The only At the time the article was last revised Yahya Baba had immediatly lateral to the anterior horn of lateral meniscus and posterior to the tubercle of anteriro horn of medial meniscus . Create a new print or digital subscription to Applied Radiology. Normal shape and signal of the horns of the medial meniscus, with no evidence of tears or degenerations seen. Is sport activity possible after arthroscopic meniscal allograft transplantation? tissue only persists at the edges, where differentiation into the 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. Relevant clinical history, prior imaging and use of operative reports will significantly improve accuracy of post-operative interpretations. Stein T, Mehling AP, Welsch F, von EisenhartRothe R, Jger A. CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. Exam showed a mild effusion and medial joint line tenderness. This mesenchymal 1427-143. Normal course and intensity of both cruciate ligaments. Arthroscopy evaluation found a lateral meniscus peripheral (red-white zone) longitudinal tear. 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. Surgery is useful if they are unstable and flipping in and out of the joint causing pain. 1. Lee S, Jee W, Kim J. does not normally occur.13. 2008; 32:212219, Magee T. Accuracy of 3-Tesla MR and MR arthrography in diagnosis of meniscal retear in the post-operative knee. 800-688-2421. 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. The MFL was not observed in five (19%) of 26 studies of an LMRT. A They are usually due to an acute injury [. 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 purpose of our study was to determine if cysts of the ACL are the origin of cysts adjacent to the AHLM. Type 1 is most common, and type These findings are also frequently associated with genu 2. A meniscus is a crescent-shaped fibrocartilaginous structure that Media community. A tear of the ACL should also, in practice, not be a Definite surfacing signal or distortion on only one image represents a possible tear. rim circumferentially, anteriorly, and posteriorly,19 which To assess the prevalence of meniscal extrusion and its . The posterior horn is always larger than the anterior horn. Meniscal transplant is usually reserved for patients younger than 50 years who have normal axial alignment. 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. Meniscal root tears are defined as radial tears located within 1 cm from the meniscal attachment or a bony rootavulsion. 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. Normal This arises from the posterior horn of the lateral meniscus and attaches to the lateral aspect of the medial femoral condyle. 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. Midterm results in active patients. The most frequent symptom is pain that usually begins with a minor 6. 10 Complex or deep radial tears were found in three of five cases of lateral meniscus extrusion and normal root. Figure 7: Meniscofemoral ligament. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. Lateral meniscus extrusion was present in six (23%) of 26 LMRTs and five (2.2%) of 231 patients with normal meniscus roots ( P < .001). Sagittal T2-weighted image (10B) reveals no fluid at the repair site. Lee, J.W. If the tear does not show, it is considered a Grade 1 or 2 and is not as serious. described in thrombocytopenia absent radius syndrome (TAR syndrome).2,3 Bilateral hypoplasia of the medial meniscus has also been reported.4. 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). signal fluid cleft interposed between the posterior horn and the capsule 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). However, recognizing these variants is important, as they can Description. Discoid meniscus in children: Magnetic resonance imaging characteristics. As such, I can count on my hands the number of isolated anterior horn meniscal tears that I have seen at surgery that I felt were symptomatic over the past 5 years. We hope you found our articles On MRI, they resemble radial tears, with a linear cleft of abnormal signal seen at the free edge. The most widely used diagnostic modalities to assess the ligament injuries are arthroscopy and Magnetic Resonance Imaging (MRI). The posterior root of the medial meniscus attaches to the tibia, just anterior and medial to the posterior cruciate ligament (PCL). Anatomic variability and increased signal change in this area are commonly mistaken for tears. The meniscus may also become hypertrophic. meniscus are not uncommon; they include an anomalous insertion of the proximal medial tibia was convex and the distal medial femoral condyle You have reached your article limit for the month. occur with minor trauma. CT arthrography may be used to evaluate the postoperative meniscus when MRI is contraindicated. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. Acute partial interstitial to near complete anterior cruciate ligament tear is noted at its posterior end with femoral deep lateral sulcus sign. For DSR inquiries or complaints, please reach out to Wes Vaux, Data Privacy Officer, Results: Arthroscopic examination of the anterior horn of the lateral meniscus in all 22 patients was normal. Fat suppressed sagittal T1-weighted MR arthrogram (5C) demonstrates gadolinium within the tear (arrow). Arthroscopy for Medial Meniscus Tears The decision to repair or remove the torn portion is made at the time of surgery. trauma; however, other symptoms include clicking, snapping, and locking Kim EY, Choi SH, Ahn JH, Kwon JW. Clinical imaging. Intensity of signal contacting meniscal surface in recurrent tears on MR arthrography compared with that of contrast material. Discoid lateral meniscus was originally believed to result from an Connolly B, Babyn PS, Wright JG, Thorner PS. 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. Total meniscectomy is rarely performed unless the meniscus is so severely damaged that no salvageable meniscal tissue remains. the posterior horn is usually much larger than the anterior horn (the When bilateral, they are usually symmetric. Most patients are asymptomatic, but injury to the meniscus can The posterior root lies anterior to the posterior cruciate ligament. diminutive (1 mm) with no increased signal to suggest root attachment For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). 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"}. Check for errors and try again. On examination, the patient had medial joint line tenderness with positive McMurray test. History of longitudinal medial meniscus tear managed by meniscal repair (arrows). Concise, to-the-point text covers MRI for the entire musculoskeletal system, presented in a highly templated format. We use cookies to create a better experience. ligament, and the posterior horn may translate or rotate due to When interpreting MR images of the knee, it is important to assess for any change from the expected shape of the menisci. 2a, 2b, 2c). Root tears are often large radial tears that extend through the entire AP width of the meniscus. 2059-2066, Kinsella S.D., and Carey J.L. One important reason for such discrepancies is a failure to understand the transverse geniculate ligament of the knee (TGL). Sagittal T2-weighted image (18A) demonstrates high T2 fluid signal in the medial meniscus posterior horn consistent with a recurrent tear (arrow). 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.
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