2002;30(2):189-192. 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. 4. Lateral meniscus posterior horn peripheral longitudinal tear managed by repair. Source: Shepard MF, et al. In the U.S., intraarticular injection of gadolinium-based contrast is off label. Tears high fibula head and a widened lateral joint space.20 Several Following meniscal allograft transplantation (Figure 17), complications occur in up to 21% of procedures, including allograft failure and progressive cartilage loss.19 Repeat operations occur in up to 35% of patients, 12% requiring conversion to total knee arthroplasty. Semin Musculoskelet Radiol 2005;9(2):11624, Chung KS, Ha JK, Ra HJ, Nam GW, Kim JG. (as previously described), meniscal cyst,26 discoid lateral meniscus in the same knee (Figure 9),25 and pathologic medial patella plica.27. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. AJR Am J Roentgenol. Kim EY, Choi SH, Ahn JH, Kwon JW. typically into the anterior cruciate ligament. The posterior cruciate ligament is intact. At 1 year, 5 of 6 were completely asymptomatic with the remaining patient minimally painful with no suggestion of meniscal symptoms. When bilateral, they are usually symmetric. The sutures are tied over a cortical fixation device or Endobutton (short arrow) with the knee flexed at 90 to secure the root repair. The camera can visualize the meniscus and other structures within the knee. 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. occur with minor trauma. Continuous meniscal tissue bridged the anterior and posterior horns of the lateral meniscus on 3 consecutive sagittal slices (Figure 1B). medial meniscus, and not be confined to the ACL as seen in an ACL tear. Because there is less pressure on the meniscus there, it is difficult to evaluate the anterior region of the meniscus. An abnormal shape may indicate a meniscal tear or a partial meniscectomy. 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. 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. Pathology - a tear that has developed gradually in the meniscus. Radiology. frequently. 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. 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. Anatomic variability and increased signal change in this area are commonly mistaken for tears. Radiographic knee dimensions in discoid lateral meniscus: Comparison with normal control. Wrisberg variant, the morphology of the meniscus may be normal, but the On the sagittal proton density-weighted image (11A), signal contacts the tibial surface. ligaments are absent, most commonly the anterior cruciate ligament (ACL) 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. A classification system developed by the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine [, Longitudinal-vertical tear. Sagittal T2-weighted image (18A) demonstrates high T2 fluid signal in the medial meniscus posterior horn consistent with a recurrent tear (arrow). 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. ; Lee, S.H. An intact meniscal repair was confirmed at second look arthroscopy. The medial meniscus is more tightly anchored than the lateral meniscus, allowing for approximately 5mm of anterior-posterior translation. hypermobility. At the time the case was submitted for publication Mostafa El-Feky had no recorded disclosures. {"url":"/signup-modal-props.json?lang=us"}, Weerakkody Y, Baba Y, Knipe H, et al. Clark CR, Ogden JA. Shepard et al have done a nice job of telling us just how frequently this mistake can be made by fellowship trained musculoskeletal radiologists. A tear of the lateral meniscus can occur from a sudden injury, or from chronic wear and overload. The anterior meniscofemoral ligament (Humphrey ligament) attaches proximally on the medial femoral condyle, inferior to the PCL insertion. At the time the article was last revised Yahya Baba had Meniscal disorders: Normal, discoid, and cysts. There 7.2 Medial and Lateral Menisci Medial meniscus is larger than the lateral meniscus and is more "open" (=less C-like) and less wide. Renew or update your current subscription to Applied Radiology. in this case were attributed to an anterior cruciate ligament tear 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). are reported cases of complete absence of the medial meniscus as horns to the meniscal diameter on a sagittal slice that shows a maximum MR imaging is useful for evaluation of many possible complications following meniscal surgery. 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. the example shown (Figures 1 and 2), the entire medial meniscus is 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. Following a meniscal repair procedure, the meniscus can be categorized as healed if there is no fluid signal in the repair, partially healed if fluid signal extends into less than 50% of the repair site, or not healed if fluid signal extends into greater than 50% of the repair site. Close clinical correlation is advised before recommending surgery based on this finding alone. Radial Tear of the Medial Meniscal Root: Reliability and Accuracy of MRI for Diagnosis. The discoid lateral-meniscus syndrome. Considered a feature of knee osteoarthritis. Kijowski et al. The reported prevalence is 0.06% to 0.3%.25 Bilateral hypoplasia of the medial meniscus has also been They may not even be apparent with an arthroscopic examination. menisci occurs. Variations in meniscofemoral ligaments at anatomical study and MR imaging. Longitudinal lateral meniscus tear status post repair (arrow). American Board of Orthopaedic Surgery Practice of the Orthopaedic Surgeon: Part-II, certification examination case mix. Extension to the anterior cortex of . 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 previous study by De Smet et al. sagittal magnetic resonance (MR) images. the rare ring-shaped meniscus, to the classification. congenital absence of the cruciate ligaments. Dickhaut SC, DeLee JC. For root tears in general, sagittal imaging may demonstrate a meniscal ghost sign. of the distal femur and proximal tibia, and in the case report of Resnick D, Goergen TG, Kaye JJ, et al. The example above demonstrates the importance of baseline MRI comparison when evaluating the postoperative meniscus. Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. ligaments and menisci causing severe knee dysplasia in TAR syndrome. meniscus is partial meniscal excision, leaving a 6- to 7-mm peripheral incomplete breakdown of the central meniscus, but this is now disputed, This is a well-done study with clinical correlation and adequate follow-up. 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 Anterior horn of the lateral meniscus: another potential pitfall in MR imaging of the knee. A slightly overweight 44-year-old male sought evaluation for medial knee pain that persisted for months after running on the beach. What causes abnormal mobility in the medial meniscus? Menisci are present in the knees and the What are the findings? of the AIMM into the ACL is classified as Type 1 (inferior third), Type 2 Increased signal intensity at the anterior horn of the lateral meniscus was seen on the images of seven of the 11 MR studies of the volunteers. This mesenchymal menisci (Figure 8). For information on new subscriptions, product Pinar H, Akseki D, Karaoglan O, et al. The lateral meniscus is produced by the varus tension and tibial IR. 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. Increased intrameniscal signal is commonly seen in the transplanted allograft but does not correlate with clinical outcome. . Arthrofibrosis and synovitis are also relatively common. Presentation - Middle-older aged individuals, non-traumatic, progressive onset of pain. The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). Radiographs may Comparison of Postoperative Antibiotic Regimens for Complex Appendicitis: Is Two Days as Good as Five Days? 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. Grade II hyperintense horizontal signal of posterior horn of medial meniscus is noted. AJR Am J Roentgenol 211(3):519527, De Smet AA. 22 year-old male with a history of ACL and MCL reconstruction and medial meniscus posterior root repair. pretzels dipped in sour cream. of the anterior horn of the medial meniscus, an inferior patella plica, Relevant clinical history, prior imaging and use of operative reports will significantly improve accuracy of post-operative interpretations. Medial meniscus posterior horn peripheral longitudinal tear (arrow) seen on the sagittal proton density-weighted image (15A) and managed by repair. Tears in the red zone have the potential to heal and are more amenable to repair. Description. Definite surfacing signal or distortion on only one image represents a possible tear. The MRI showed complete ACL tear with displaced bucket handle medial meniscus tear. It can be divided into five segments: anterior horn, anterior, middle and posterior segments, and posterior horn. 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). Neuschwander DC, Drez D Jr, Finney TP. Anterior tibial marrow edema and organized trabecular fracture measuring 16 mm AP, 18 mm transverse. 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 . Stein T, Mehling AP, Welsch F, von EisenhartRothe R, Jger A. According to one source, they are thought to account for ~10% of all arthroscopic meniscectomies 5. posterior horn usually measures 12 mm to 16 mm in the sagittal plane in treatment for stable complete or incomplete types of discoid lateral Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. Lee, J.W. rim circumferentially, anteriorly, and posteriorly,19 which This case features the following signs of meniscal tear: Case courtesy, Prof. Dr. Khaled Matrawy, Professor of radiology, Alexandria university, Egypt. On MRI, longitudinal tears appear as a vertical line of abnormal signal contacting articular surface. Discoid meniscus in children: Magnetic resonance imaging characteristics. Knee Surg Sports Traumatol Arthrosc 2011; 19:147157, Gwathmey F.W., Golish S.R., Diduch D.R., et al: Complications in brief: meniscus repair. This case is almost identical to the previous case with a different clinical history. to tear. 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 . 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. 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. On sagittal proton-density and T2-weighted images, this lesion was demonstrated by sensitive but nonspecific signs, such as the flipped meniscus . Otherwise, the increased vascularity in children has sometimes led to false-positive reading of a meniscus tear. Arthroscopy for Medial Meniscus Tears The decision to repair or remove the torn portion is made at the time of surgery. Objectives: Low-field MRI at 0.55 Tesla (T) with deep learning image reconstruction has recently become commercially available. We look forward to having you as a long-term member of the Relias 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. One of the most frequent indications for arthroscopic knee surgery is a meniscal tear.1 It is estimated that 1 million meniscus surgeries are performed in the U.S. annually with 4 billion dollars in associated direct medical expenditures.2 Meniscal surgeries include partial meniscectomy, meniscal repair and meniscal replacement. 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. However, clinically significant tears that can mechanically impinge were unlikely to have been missed. They maintain a relatively constant distance from the periphery of the meniscus [. 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. After failing conservative management with NSAIDs, PT, and activity modification, he underwent an MRI. MR imaging evaluation of the postoperative knee. Analytical, Diagnostic and Therapeutic Techniques and Equipment 13. diminutive (1 mm) with no increased signal to suggest root attachment 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. variant, and discoid medial meniscus. The lateral meniscus is one of two fibrocartilaginous menisci of the knee. 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. Generally, meniscal injury. CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. Disadvantages include increased cost, increased patient time, potential for adverse reactions to contrast agent compared to conventional MRI and lack of joint distention. When it involves the posterior root, medial root tears are easier to diagnose than lateral root tears. of a case of discoid medial cartilage, with an embryological note. Rohren EM, Kosarek FJ, Helms CA. The MRI sign of a radial tear is a linear, vertical cleft of abnormal high signal at the free edge (Fig. Magnetic resonance imaging (MRI) and computed tomography (CT) arthrography are both well suited for evaluation of these lesions though somewhat limited by cost and access for MRI and by invasiveness for CT arthrography . A meniscus is a crescent-shaped fibrocartilaginous structure that The MRI also demonstrated moderate degenerative spurring at the lateral joint compartment, a large knee joint effusion with . immediatly lateral to the anterior horn of lateral meniscus and posterior to the tubercle of anteriro horn of medial meniscus . 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. described in thrombocytopenia absent radius syndrome (TAR syndrome).2,3 Bilateral hypoplasia of the medial meniscus has also been reported.4. Brody J, Lin H, Hulstyn M, Tung G. Lateral Meniscus Root Tear and Meniscus Extrusion with Anterior Cruciate Ligament Tear. The anterior and posterior meniscofemoral ligaments (Humphrey and Wrisberg respectively) are commonly present with one or both found in 93-100% of patients. Their conclusion that one should not perform surgery unless clinical correlation exists with effusions, mechanical catching or locking, or the failure to respond to nonoperative measures I believe is a good recommendation that we can all follow. We hope you found our articles 2a, 2b, 2c). Thirty-one of these patients underwent subsequent arthroscopic evaluation to allow clinical correlation. Total meniscectomy is rarely performed unless the meniscus is so severely damaged that no salvageable meniscal tissue remains. Tolo VT. Congenital absence of the menisci and cruciate ligaments of the knee: A case report. Tibial meniscal dynamics using three-dimensional reconstruction of magnetic resonance images. St. Louis County's newspaper of politics and culture Klingele KE, Kocher MS, Hresko MT, et al. Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. It is located in the lateral portion of the knee interior of the knee joint. Magn Reson Imaging Clin N Am 2014;22(4): 517555, White LM, Schweitzer ME, Weishaupt D, Kramer J, Davis A, Marks PH. Meniscal transplant is usually reserved for patients younger than 50 years who have normal axial alignment. The sensitivity of mri in detecting meniscal tears is generally good, ranging from 70-98%, with specificity in the same range in many studies. Kijowski et al. 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. 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. acromioclavicular, sternoclavicular, and temporomandibular joints. The Journal of bone and joint surgery American volume. 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. of the Wrisberg ligament in patients with a complete lateral discoid Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. 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. 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. 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. Sometimes T2 signal in a healed tear may look similar to fluid. does not normally occur.13. Posterior root repair (Figure 16) is being performed with increasing frequency and has been shown to have better outcomes and decreased risk of osteoarthritis compared to posterior root tears treated non-operatively. anterior horn of the medial meniscus into the anterior cruciate ligament There are 3 main types, according to the Watanabe classification:18. Pain is typically medial and activity-related (e.g. On imaging alone, the radiologist may not be able to distinguish a residual tear (failed repair) from a recurrent tear in the same location. ligament will help to exclude these conditions.5 In the first The medial meniscus covers 60% of the medial compartment. diagnostic dilemma, as the AIMM band will be seen to extend to the medial meniscus are extremely uncommon and should not be a diagnostic Normal shape and signal of the horns of the medial meniscus, with no evidence of tears or degenerations seen. 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 [. History of medial meniscus posterior horn partial meniscectomy. CT arthrography is a recommended alternative for patients who are not MR eligible. Anterior horn lateral meniscus tear A female asked: Mri: "macerated anterior horn lateral meniscus with inferiorly surfacing tear. Discoid medial meniscus. Imaging characteristics of the Is sport activity possible after arthroscopic meniscal allograft transplantation? The anterior horn inserts on the tibia and continues laterally to the anterior horn of the lateral meniscus via the transverse intermeniscal ligament. reported.4. Again, this emphasizes the importance of accurate history, prior imaging and operative reports. Their 74% false-positive rate I believe is accurate and one that we can incorporate mentally into our practice as we evaluate patients and the MRI scan results. This emphasizes the importance of meniscal repair over meniscectomy when possible and the need for meniscal preservation when a partial meniscectomy is necessary. tissue only persists at the edges, where differentiation into the 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.
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