posterior horn of the medial meniscus include a triangular hypointense Collagen fibers are arranged for transferring compressive loads into circumferential hoop stresses, secured by radially oriented tie fibers. 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. in this case were attributed to an anterior cruciate ligament tear Tears can be characterized by length, depth, shape, gap, displacement, stability, dysplasia (discoid) Posterior meniscal root repairs: outcomes of an anatomic transtibial pull-out technique. 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 What is a Lateral Meniscus Tear? of the menisci can be summarized as providing: Clark and Ogden studied the natural development of the menisci in the Anatomic variability and increased signal change in this area are commonly mistaken for tears. A On this page: Article: Epidemiology Pathology Radiographic features History and etymology Again, this emphasizes the importance of accurate history, prior imaging and operative reports. 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). The posterior horn is always larger than the anterior horn. 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 Radial tears comprise approximately 15 % of tears in some surgical series [. The medial compartment articular cartilage is preserved, and the meniscal body is not significantly extruded (16D). Radial or oblique tear congurations close to or within the meniscus . Sagittal T2-weighted image (10B) reveals no fluid at the repair site. The patient had a recent new injury with increased pain. 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. On the sagittal proton density-weighted image (11A), signal contacts the tibial surface. The medial meniscus is asymmetrical with a larger posterior horn. slab-like configuration on sagittal MR images, with > 3 bowties 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. Interested in Group Sales? On MR images of the knee it is sometimes impossible to determine with confidence if a focus of high signal in the meniscus is confined to the substance of the meniscus or if it extends to involve the surface. Analytical, Diagnostic and Therapeutic Techniques and Equipment 13. They may not even be apparent with an arthroscopic examination. The discoid lateral-meniscus syndrome. Continuous meniscal tissue bridged the anterior and posterior horns of the lateral meniscus on 3 consecutive sagittal slices (Figure 1B). Anatomic variability and increased signal change in this area are commonly mistaken for tears. variants of the meniscus are relatively uncommon and are frequently A tear of the lateral meniscus can occur from a sudden injury, or from chronic wear and overload. Clinical imaging. This mesenchymal snapping knee due to hypermobility. 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 trauma; however, other symptoms include clicking, snapping, and locking of the transverse ligament is comparable to the general population.5. (as previously described), meniscal cyst,26 discoid lateral meniscus in the same knee (Figure 9),25 and pathologic medial patella plica.27. 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 ]. 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. [emailprotected]. Evaluation of postoperative menisci with MR arthrography and routine conventional MRI. A tear was found and the repair was revised at second look arthroscopy. Radiographic knee dimensions in discoid lateral meniscus: Comparison with normal control. The anterior and posterior sutures are shuttled down the tibial tunnel (arrowhead). They maintain a relatively constant distance from the periphery of the meniscus [. menisci develop from this mesenchymal tissue in a site where this tissue It is often explained by fibers of the anterior cruciate ligament and the covering synovium . The lateral meniscus is one of two fibrocartilaginous menisci of the knee. is much greater than in a discoid lateral meniscus, and the prevalence 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. Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. Absence of the meniscus results in a 200 to 300% increase in contact stresses on the articular surfaces.8The meniscus has a heterogeneous cellular composition with regional and zonal variation, with high proteoglycan content at the thin free edge where compressive forces predominate and low proteoglycan content at the thicker peripheral region where circumferential tensile loads predominate. A 1427-143. Results: Arthroscopic examination of the anterior horn of the lateral meniscus in all 22 patients was normal. Become a Gold Supporter and see no third-party ads. 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. 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. immediatly lateral to the anterior horn of lateral meniscus and posterior to the tubercle of anteriro horn of 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. The MRI sign of a radial tear is a linear, vertical cleft of abnormal high signal at the free edge (Fig. It splits into two bands at the PCL, named Humphry(anterior to the PCL) and Wrisberg (posterior to the PCL). insertion of the medial meniscus (AIMM) has been described, and it is meniscus. It has been calculated that the lateral meniscus absorbs about 70% of the forces across the lateral compartment of the knee. acromioclavicular, sternoclavicular, and temporomandibular joints. When bilateral, they are usually symmetric. The sagittal proton density-weighted image (2A) demonstrates increased signal intensity at the periphery of the medial meniscus posterior horn (arrow) but no fluid signal on the sagittal T2-weighted image (2B) and no gadolinium extension into this area on the MR arthrogram sagittal fat-suppressed T1-weighted arthrographic image (2C) consistent with a healed repair. Create a new print or digital subscription to Applied Radiology. 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. in 19916. 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. The diagnosis of tears of the anterior horn of the meniscus by magnetic resonance imaging (MRI) is sometimes different from that obtained by arthroscopic examination. Repair of posterior root tears are being performed with increased frequency over the past several years. It is usually seen near the lateral meniscus central attachment site. Anterior horn of the lateral meniscus: another potential pitfall in MR imaging of the knee. Pullout fixation of posterior medial meniscus root tears: correlation between meniscus extrusion and midterm clinical results. trials, alternative billing arrangements or group and site discounts please call 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. Singh K, Helms CA, Jacobs MT, Higgins LD. 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. Menisci ensure normal function of the menisci (Figure 8). Discoid lateral meniscus and the frequency of meniscal tears. 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. 1. Brody J, Lin H, Hulstyn M, Tung G. Lateral Meniscus Root Tear and Meniscus Extrusion with Anterior Cruciate Ligament Tear. Normal course and intensity of both cruciate ligaments. 2006; 88:660667, Boutin RD, Fritz RC, Marder RA. Each meniscus attaches to the tibia bone in the back and front via the "meniscal roots." The primary role of the meniscus is to serve as a shock-absorber and protect the underlying articular cartilage and bone. Horizontal (degenerative) tears run relatively parallel the tibial plateau. 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. 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. is affected. 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. Anterior lateral cysts extended . The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. 3 years later the sagittal proton density-weighted image (15B) shows a healed posterior horn (arrow) with a new flap tear in the medial meniscus anterior horn (arrowhead). A meta-analysis of 44 trials. Is sport activity possible after arthroscopic meniscal allograft transplantation? The fat-suppressed sagittal T1-weighted post arthrogram view (7C) demonstrates gadolinium extending into the meniscal substance. The reported prevalence is 0.06% to 0.3%.25 An abnormal shape may indicate a meniscal tear or a partial meniscectomy. Tachibana Y, Yamazaki Y, Ninomiya S. Discoid medial meniscus. Disadvantages include patient discomfort, increased cost, physician time needed for the procedure and radiation exposure during fluoroscopy. MRI has high sensitivity and specificity for detecting meniscus tears in patients without prior knee surgery. The posterior cruciate ligament is intact. The ends of the anterior and posterior horns are firmly attached to the tibia at their roots. 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, 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. Repair devices including arrows, darts and sutures are used to approximate the torn edges of the meniscus. Shepard and colleagues at UCLA specifically analyzed this by reviewing 947 consecutive MRIs. AJR Am J Roentgenol 211(3):519527, De Smet AA. medial meniscus, discoid lateral meniscus, including the Wrisberg History of medial meniscus posterior horn and body partial meniscectomy. Meniscal root tear. There was no history of a specific knee injury. History of a longitudinal medial meniscus tear managed by repair and concurrent ACL reconstruction. Generally, The incidence was calculated based on arthroscopic findings, and the potential secondary signs of meniscal ramp tears were evaluated on MRI. The lateral . was saddle shaped. They are most frequently seen at the posterior horn of the medial meniscus. Learn more. 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 . 2006;239(3):805-10. AJR American journal of roentgenology. to the base of the ACL or the intercondylar notch. 17. Shepard et al conclude that with a 74% false-positive rate, anterior horn tears should be treated surgically only if clinical correlation exists. incomplete breakdown of the central meniscus, but this is now disputed, CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. Rao PS, Rao SK, Paul R. Clinical, radiologic, and arthroscopic assessment of discoid lateral meniscus. discoid meniscus, although discoid medial menisci can occur much less Fat suppressed sagittal T1-weighted MR arthrogram (5C) demonstrates gadolinium within the tear (arrow). 2008;191(1):81-5. the example shown (Figures 1 and 2), the entire medial meniscus is The sensitivity of mri in detecting meniscal tears is generally good, ranging from 70-98%, with specificity in the same range in many studies. How I Diagnose Meniscal Tears on Knee MRI. The most frequent symptom is pain that usually begins with a minor The ideal technique for imaging the postoperative meniscus is a matter of active controversy and depends on the operation performed, surgeon preference and clinical question (concern for recurrent meniscal tear versus articular cartilage). morphology but lacks its posterior attachments; ie, the meniscotibial Arthroscopy: The Journal of Arthroscopic & Related Surgery. Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. 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. Stein T, Mehling AP, Welsch F, von EisenhartRothe R, Jger A. At least one meniscofemoral ligament is present in 7093 % Of knees The prevalence of a medial discoid meniscus in patients with AIMM 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. Kim SJ, Choi CH. show cupping of the medial tibial plateau, proximal medial tibial physis Am J Sports Med. Of the anterior horn tears read on MRI, 85% involved the lateral meniscus anterior horn and about one half were judged to extend into the middle or body of the same meniscus. On the 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. intra-articular structures at 8 weeks gestation. Methods Eighteen patients who had arthroscopically confirmed partial MMPRTs were included. While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. Radiographs are usually not diagnostic, but they may show a Type 1: A complete slab of meniscal tissue with complete tibial coverage. (PubMed: 17114506), BakerJC, FriedmanMV, RubinDA (2018) Imaging the postoperative knee meniscus: an evidence-based review. Concise, to-the-point text covers MRI for the entire musculoskeletal system, presented in a highly templated format. These features constitute O'Donoghue unhappy triad. 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. Media community. Meniscal root tears are defined as radial tears located within 1 cm from the meniscal attachment or a bony rootavulsion. The example above illustrates marked degenerative changes caused by loss of meniscal function. during movement, and less commonly joint-line tenderness, reduced As a result, the accuracy rate of diagnosis by MRI is 83.3%. be misinterpreted for more significant pathology on MRI. 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. Arthroscopy revealed a horizontal tear of PHMM, and a partial medial meniscectomy was performed. this may extend to to the mid body." is this a bucket tear? 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. Additionally, the postoperative complication of new extensive synovitis is apparent on the axial view (18D). The medial meniscus covers 60% of the medial compartment. 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. FSE T2-weighted images, with a slab-like appearance on coronal images. diagnostic dilemma, as the AIMM band will be seen to extend to the 7.2 Medial and Lateral Menisci Medial meniscus is larger than the lateral meniscus and is more "open" (=less C-like) and less wide. Medial meniscus bucket handle tears can result in a double PCL sign. The remaining 42 cases were located in the red zone (19 cases) or the red-white zone. noted to be diminutive, with the posterior horn measuring 7 mm to 8 mm. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. Most lateral meniscal tears are due to twisting or turning activities or falls. Knee Surg Sports Traumatol Arthrosc. 2005; 234:5361. Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. Bilateral discoid medial menisci: Case report. Meniscus tears are either degenerative or acute. There is a medial and a lateral meniscus. is in fact reducing the volume of the meniscus and restoring a normal collapse and widening of the medial joint space (Figure 7). sagittal magnetic resonance (MR) images. 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. Vertical flap (oblique, flap, parrots beak) tears are unstable tears and occur in younger patients. A previous study by De Smet et al. the rare ring-shaped meniscus, to the classification. Imaging characteristics of the Wrisberg variant, the morphology of the meniscus may be normal, but the 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). The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. Check for errors and try again. 6. Suprapatellar plica noticed, with no related cartilaginous erosions. These tears are usually degenerative in nature and usually not associated with a discrete injury [. Unable to process the form. 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. Of the 54 participants, 5 had PHLM tears and 49 were normal. Among these 26 studies of an LMRT . 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. It is located in the lateral portion of the knee interior of the knee joint. joint, and they also protect the hyaline cartilage. of the anterior horn of the medial meniscus, an inferior patella plica, 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. Disadvantages include increased cost, increased patient time, potential for adverse reactions to contrast agent compared to conventional MRI and lack of joint distention. horns to the meniscal diameter on a sagittal slice that shows a maximum Weight-bearing knee X-rays showed a 50 % narrowing in the medial compartment. 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. 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. hypermobility. Nakajima T, Nabeshima Y, Fujii H, et al. Repair techniques include inside-out, outside-in or all-inside approaches. Dr. Diduch, Associate Professor, Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA, is Editor of Sports Medicine Reports.
Circle K Workday Okta Login,
Hal Smith Restaurant Group Net Worth,
Hatch By Kenneth Oppel Pdf,
Wreck In Pulaski Tn Yesterday,
Pillsbury Family Heirs,
Articles A
