Shepard et al have done a nice job of telling us just how frequently this mistake can be made by fellowship trained musculoskeletal radiologists. In cases like this, MR arthrography is quite helpful. 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. hypermobility. Ross JA,Tough ICK, English TA. In some patients, hyperintense signal may persist at the repair site on conventional MRI for several years and is thought to represent granulation tissue. 2012;199(3):481-99. Singh K, Helms CA, Jacobs MT, Higgins LD. 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. Youderian A, Chmell S, Stull MA. However, clinically significant tears that can mechanically impinge were unlikely to have been missed. Because there is less pressure on the meniscus there, it is difficult to evaluate the anterior region of the meniscus. Of these 45 patients, there was an average of 3.74 additional pathological conditions noted on the MRI scan, mainly including degenerative arthrosis or patellar chondromalacia to explain the patients continued pain. Tolo VT. Congenital absence of the menisci and cruciate ligaments of the knee: A case report. Discoid lateral meniscus and the frequency of meniscal tears. Radiographs are usually not diagnostic, but they may show a It splits into two bands at the PCL, named Humphry(anterior to the PCL) and Wrisberg (posterior to the PCL). the medial meniscus. Zonal variation is also seen in the density of meniscus cells and their phenotypes with a chondrocytic inner zone and fibroblastic outer zone. Type Results: Arthroscopic examination of the anterior horn of the lateral meniscus in all 22 patients was normal. The trusted source for healthcare information and CONTINUING EDUCATION. Meniscus tears, indicated by MRI, are classified in three grades. Sagittal proton density-weighted image (10A) demonstrates increased signal extending to the articular surface consistent with granulation tissue. diagnostic dilemma, as the AIMM band will be seen to extend to the Arthrofibrosis and synovitis are also relatively common. instance, tears of the lateral aspect of the anterior horn of the 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). They may not even be apparent with an arthroscopic examination. American Board of Orthopaedic Surgery Practice of the Orthopaedic Surgeon: Part-II, certification examination case mix. A meniscus is a crescent-shaped fibrocartilaginous structure that medial meniscus are extremely uncommon and should not be a diagnostic In this section, the major patterns of tears are described and depicted in MRIs and arthroscopy images. Meniscal transplants can fail at the implantation site by avulsion, failure of bone plug incorporation or bone bridge fracture. ligament and meniscal fascicles. 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 congenital absence of the cruciate ligaments. To assess the prevalence of meniscal extrusion and its . Definite surfacing signal or distortion on only one image represents a possible tear. 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. of the menisci can be summarized as providing: Clark and Ogden studied the natural development of the menisci in the Tears in the red zone have the potential to heal and are more amenable to repair. 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 [. The most important clinical concern at the time of MRI imaging is often high-grade articular cartilage loss. Evaluation of postoperative menisci with MR arthrography and routine conventional MRI. It is believed that discoid Generally, They maintain a relatively constant distance from the periphery of the meniscus [. Bilateral discoid medial menisci: Case report. Radiology. Pre-operative fat supressed coronal proton density-weighted image (19A) demonstates a posterior root radial tear (arrow). 1991;7(3):297-300. Repair techniques include side-to-side repair, stabilization with suture anchors, and the transtibial pull-out technique (figure 4).12. MR imaging evaluation of the postoperative knee. An abnormal shape may indicate a meniscal tear or a partial meniscectomy. Stay up to date with the latest in Practical Medical Imaging and Management with Applied Radiology. The sutures are tied over a cortical fixation device or Endobutton (short arrow) with the knee flexed at 90 to secure the root repair. meniscal diameter. They often tend to be radial tears extending into the meniscal root. An intact meniscal repair was confirmed at second look arthroscopy. 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. 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. Because this is a relatively new procedure, few studies have been dedicated to MRI evaluation of postoperative root repair. Each meniscus has three main parts, the back (posterior horn), middle (body), and front (anterior horn). ; Lee, S.H. Am J Sports Med 2017; 45:884891, Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, et al. The medial meniscus covers 60% of the medial compartment. Variations in meniscofemoral ligaments at anatomical study and MR imaging. 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. Concise, to-the-point text covers MRI for the entire musculoskeletal system, presented in a highly templated format. 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. 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). 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 [. least common is complete congenital absence of the menisci. 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. ADVERTISEMENT: Supporters see fewer/no ads. The common insertion of the anterior cruciate ligament (ACL) and the AHLM root may provide a pathway for disease. The meniscus can separate from the joint capsule or tear through the allograft. 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. Intensity of signal contacting meniscal surface in recurrent tears on MR arthrography compared with that of contrast material. Figure 8: Medial oblique menisco-meniscal . Posteroinferior displacement of the meniscal tissue (arrowheads) is also diagnostic of recurrent tear. For DSR inquiries or complaints, please reach out to Wes Vaux, Data Privacy Officer, Meniscal root tears are defined as radial tears located within 1 cm from the meniscal attachment or a bony rootavulsion. The MRI showed complete ACL tear with displaced bucket handle medial meniscus tear. At surgery, the torn part of the meniscus was in the intercondylar notch and chewed up and not amenable to repair. Figure 7: Meniscofemoral ligament. Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. Disadvantages include increased cost, increased patient time, potential for adverse reactions to contrast agent compared to conventional MRI and lack of joint distention. 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). are reported cases of complete absence of the medial meniscus as 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. A previous study by De Smet et al. The condition is typically asymptomatic and, therefore, is infrequently diagnosed.14 An alternative way of fastening the allograft to the donor knee involves harvesting the meniscus with a small bone plug attached to each root and then securing the plugs within osseous tunnels drilled in the recipient tibia. We look forward to having you as a long-term member of the Relias Examination of the knee showed a mild effusion, 1+ Lachman, positive Pivot shift, and mild tenderness to both medial and lateral joint lines. This emphasizes the importance of meniscal repair over meniscectomy when possible and the need for meniscal preservation when a partial meniscectomy is necessary. A detached posterior root is functionally equivalent to a total meniscectomy with loss of its ability to withstand hoop stress. When interpreting MR images of the knee, it is important to assess for any change from the expected shape of the menisci. of the anterior horn of the medial meniscus, an inferior patella plica, There are 3 main types, according to the Watanabe classification:18. posterior horn usually measures 12 mm to 16 mm in the sagittal plane in The most common congenital anomalies affect the lateral meniscus, most commonly a Interested in Group Sales? The meniscus may also become hypertrophic. Materials and methods . attachment of the posterior horn is the Wrisberg meniscofemoral The torn edges are aligned, and stable fixation applied with sutures or bioabsorbable implants at approximately 5 mm intervals. 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. | 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. They are most frequently seen at the posterior horn of the medial meniscus. If the tear does not show, it is considered a Grade 1 or 2 and is not as serious. 4). What is a Grade 3 meniscus tear? You have reached your article limit for the month. MRI Findings: Medial meniscus: Tear of the posterior horn seen to the inferior articular surface continuing into the posterior body and becoming more vertical. These features constitute O'Donoghue unhappy triad. Klingele KE, Kocher MS, Hresko MT, et al. 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. Congenital discoid cartilage. Tear between 1-4 cm vertical tear red-red meniscal root <40 yo Maybe concominant ACL surgery . Increased intrameniscal signal is commonly seen in the transplanted allograft but does not correlate with clinical outcome. The Journal of bone and joint surgery American volume. Discoid lateral meniscus: Prevalence of peripheral rim instability. This article focuses on This is a critical differentiation because the latter represents meniscal tears that can be Magnetic resonance imaging (MRI) of both knee joints showed an almost complete absence of the anterior and posterior horns of the medial meniscus, except for the peripheral portion, hypoplastic anterior horns and tears in the posterior horns of the lateral meniscus in both knees (Fig. 6. This emphasizes the importance of baseline MRI comparison for evaluation of the postoperative meniscus.3. 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. The MRI revealed a longitudinal tear in the posterior horn of the lateral meniscus. morphology. This mesenchymal Check for errors and try again. . both enjoyable and insightful. When it involves the posterior root, medial root tears are easier to diagnose than lateral root tears. 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 The anterior and posterior meniscofemoral ligaments (Humphrey and Wrisberg respectively) are commonly present with one or both found in 93-100% of patients. may simulate a peripheral tear (Figure 6).23 The only In the previously reported cases, as well as in this case, the menisci occurs. and ACL tears can be mistaken for AIMM, but carefully tracing the 800-688-2421. 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. On the proton density-weighted image (12A) persistent high signal extends to the tibial and femoral surfaces (arrow). 2006; 88:660667, Boutin RD, Fritz RC, Marder RA. Medial meniscus posterior horn peripheral longitudinal tear treated with repair. The meniscus root plays an essential role in maintaining the circumferential hoop tension and preventing meniscal displacement. Discoid lateral meniscus was originally believed to result from an to tear. Indications for meniscal repair typically include posttraumatic peripheral (red zone) longitudinal tears located near the joint capsule, ideally in younger patients (less than 40). Discoid lateral meniscus. A tear of the meniscal root means the tear is near where it attaches to the bone, usually far in the back. The purpose of our study was to determine if cysts of the ACL are the origin of cysts adjacent to the AHLM. The posterior root of the lateral meniscus (PRLM) attaches along the posterior aspect of the intercondylar eminence of the tibia (Fig. an adult), and approximately twice the size of the anterior horn on When bilateral, they are usually symmetric. Type 2: An incomplete slab of meniscal tissue with 80% coverage of the lateral tibial plateau. On this page: Article: Epidemiology Pathology Radiographic features History and etymology Thus, the loss of the lateral meniscus can often lead to rather rapid onset of osteoarthritis. Most patients are asymptomatic, but injury to the meniscus can 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. {"url":"/signup-modal-props.json?lang=us"}, El-Feky M, Flipped meniscus - anterior horn lateral meniscus. Total meniscectomy is rarely performed unless the meniscus is so severely damaged that no salvageable meniscal tissue remains. Clark CR, Ogden JA. signal fluid cleft interposed between the posterior horn and the capsule does not normally occur.13. Studies on meniscus root tears have investigated the relationship of osteoarthritis and an anterior cruciate ligament tear. 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. 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. Menisci ensure normal function of the Methods Eighteen patients who had arthroscopically confirmed partial MMPRTs were included. 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. 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. Arthroscopy revealed a horizontal tear of PHMM, and a partial medial meniscectomy was performed. 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. Kijowski et al. Normal Surgery is useful if they are unstable and flipping in and out of the joint causing pain. The shape of the meniscus is formed at the eighth week of 10 Meniscal disorders: Normal, discoid, and cysts. 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. The most frequent symptom is pain that usually begins with a minor Medial meniscus posterior horn peripheral longitudinal tear (arrow) seen on the sagittal proton density-weighted image (15A) and managed by repair. 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. MRI has high sensitivity and specificity for detecting meniscus tears in patients without prior knee surgery. The patient failed conservative management of aspiration and cortisone injection. Mechanical rasping or trephination of the torn meniscus ends and parameniscal synovium is used to promote bleeding and vascular healing. Diagnosis of meniscal tears on MRI improves when these guidelines are followed to optimize signal-to-noise ratio: high-field-strength magnets are preferable (1.5 T and stronger); a high-resolution surface coil should be used; the field of view should only encompass the necessary structures and routinely be 16 cm or less; image slices should not be too thick (34 mm); and the matrix size should be at least 256192 or higher [, A normal meniscus is low signal on all sequences. The discoid lateral-meniscus syndrome. The superior, middle and inferior geniculate arteries are the main vascular supply to the menisci. A tear was found and the repair was revised at second look arthroscopy. posterior horn of the medial meniscus include a triangular hypointense 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. Extension to the anterior cortex of . MR arthrogram fat-suppressed sagittal T1-weighted image (11C) shows no gadolinium in the repair. However, recognizing these variants is important, as they can This injury is biomechanically comparable to a total meniscectomy, leading to compromised hoop stressesresulting in decreased tibiofemoral contact area and increased contact pressures in the involved compartment.These changes are detrimental to the articular cartilage and . typically into the anterior cruciate ligament. The medial meniscus is asymmetrical with a larger posterior horn. The patient had a recent new injury with increased pain. Radial Tear of the Medial Meniscal Root: Reliability and Accuracy of MRI for Diagnosis. Discoid lateral meniscus of the knee joint: Nature, mechanism, and operative treatment. 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 . bilaterally absent menisci reported by Tolo et al,3 the A displaced longitudinal tear is a "bucket handle" tear. this may extend to to the mid body." is this a bucket tear? tear. A tear of the anterior horn of the lateral meniscus is damage to the front part of one of the two structures that act as shock absorbers between the thigh bone and the lower leg, explains The Steadman Clinic. A classification system developed by the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine [, Longitudinal-vertical tear. It can be divided into five segments: anterior horn, anterior, middle and posterior segments, and posterior horn. 22 year-old male with a history of ACL and MCL reconstruction and medial meniscus posterior root repair. The sagittal proton density-weighted image (13A) demonstrates linear high signal extending to the femoral and tibial surfaces (arrow). 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. 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. The clinical significance of anterior horn meniscal tears diagnosed on magnetic resonance images. Suprapatellar plica noticed, with no related cartilaginous erosions. asymptomatic, although there is a greater propensity for discoid menisci trials, alternative billing arrangements or group and site discounts please call horn of the lateral meniscus, and oblique tear orientation In the present study, the patients analyzed came from the have been the most difficult for imaging planes to visualize same geographical area .
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