By continuing to use our site, you consent to the use of cookies outlined in our Privacy Policy. 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. ligament and meniscal fascicles. Both horns of the medial meniscus are triangular with sharp points. congenital anomalies affect the lateral meniscus, most commonly a 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 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 ]. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. Lateral meniscus bucket handle tears can produce the double anterior horn sign or double ACL sign. While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. AJR Am J Roentgenol 211(3):519527, De Smet AA. Lateral meniscus extrusion was present in six (23%) of 26 LMRTs and five (2.2%) of 231 patients with normal meniscus roots ( P < .001). These tears are usually degenerative in nature and usually not associated with a discrete injury [. > 20% ratio of meniscus to tibia on the coronal image; Minimum diameter 14-15 mm on a midcoronal image; 75% Surgical Outcomes Lysholm Score AJR Am J Roentgenol. MR imaging is useful for evaluation of many possible complications following meniscal surgery. What Is a Tear of the Anterior Horn of the Lateral Meniscus? 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 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. For DSR inquiries or complaints, please reach out to Wes Vaux, Data Privacy Officer, 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. . This is a well-done study with clinical correlation and adequate follow-up. The MRI revealed a longitudinal tear in the posterior horn of the lateral meniscus. Discoid lateral meniscus APPLIED RADIOLOGY 2006; 88:660667, Boutin RD, Fritz RC, Marder RA. Anterior horn of the lateral meniscus: another potential pitfall in MR How I Diagnose Meniscal Tears on Knee MRI : American Journal of Associated anomalies in a discoid medial In the U.S., intraarticular injection of gadolinium-based contrast is off label. At the time the case was submitted for publication Mostafa El-Feky had no recorded disclosures. Comparison of Medial and Lateral Meniscus Root Tears - PLOS Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. instance, tears of the lateral aspect of the anterior horn of the Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. Meniscal Roots: Current Concepts Review Root tears are associated with a high risk for osteoarthritis. the menisci of the knees. Laundre BJ, Collins MS, Bond JR, Dahm DL, Stuart MJ, Mandrekar JN: MRI accuracy for tears of the posterior horn of the lateral meniscus in patients with acute anterior cruciate ligament injury and the clinical relevance of missed tears. to tear. asymptomatic, although there is a greater propensity for discoid menisci Am J Sports Med. structure on sagittal images on T1, proton density, and fat-saturated 7 Therefore, it is important for the radiologist to be familiar with the appearance of a recurrent tear versus an untorn postoperative meniscus. 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. ; Lee, S.H. A characteristic MRI finding to diagnose a partial tear of the medial Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. They are most frequently seen at the posterior horn of the medial meniscus. The Postoperative Meniscus - Radsource 2a, 2b, 2c). The self-reported complication rate for partial meniscectomy is 2.8% and meniscus repair is 7.6%. Flipped meniscus - anterior horn lateral meniscus | Radiology Case Radial Meniscal Tear - ProScan Education - MRI Online pivoting). Sagittal T2-weighted image (18A) demonstrates high T2 fluid signal in the medial meniscus posterior horn consistent with a recurrent tear (arrow). 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;20(10):2098-103. Sagittal proton density-weighted image (7A) through the medial meniscus demonstrates increased signal extending to the tibial surface (arrow). Also, the inferior patella plica inserts on the 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. Youderian A, Chmell S, Stull MA. The insertion site 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. 4. sagittal magnetic resonance (MR) images. 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 . 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. Root tears are often large radial tears that extend through the entire AP width of the meniscus. Magnetic resonance imaging of the postoperative meniscus: resection, repair, and replacement. 2014; 43:10571064, McCauley TR. Volunteerism and Sports Medicine: Where do We Stand? Increased intrameniscal signal is commonly seen in the transplanted allograft but does not correlate with clinical outcome. menisci (Figure 8). . For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. 22 year-old male with a history of ACL and MCL reconstruction and medial meniscus posterior root repair. Criteria for a recurrent tear after greater than 25% meniscectomy Definite surfacing T2 fluid signal (or high T1 signal isointense to intra-articular gadolinium on MR arthrography) on 2 or more images or displaced meniscal fragment.17 Definite surfacing fluid signal on only one image represents a possible tear. : Complications in brief: arthroscopic partial meniscectomy. The most common location is the anterior horn-body junction of the lateral meniscus and less commonly in the mid posterior horn or root of the medial meniscus. Most patients are asymptomatic, but injury to the meniscus can 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. Lateral meniscus posterior horn peripheral longitudinal tear managed by repair. 1427-143. Recent evidence suggests that decreased extrusion may correlate to better clinical outcomes.18. to the base of the ACL or the intercondylar notch. morphology but lacks its posterior attachments; ie, the meniscotibial Skeletal radiology. Become a Gold Supporter and see no third-party ads. 9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. The knee is a complex synovial joint that can be affected by a range of pathologies: ADVERTISEMENT: Supporters see fewer/no ads, Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. A meniscus is a crescent-shaped fibrocartilaginous structure that The medial meniscus is more tightly anchored than the lateral meniscus, allowing for approximately 5mm of anterior-posterior translation. Pagnani M, Cooper D, Warren R. Extrusion of the Medial Meniscus. tear. runs from the anterior horn of the medial meniscus to either the ACL or On medial posterior root tears there is often 2: On posterior root radial tears of the lateral meniscus, the appearance may be similar to radial tears in other locations. Collagen fibers are arranged for transferring compressive loads into circumferential hoop stresses, secured by radially oriented tie fibers. 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). Anterior horn of the lateral meniscus: another potential - PubMed Longitudinal medial meniscus tear managed by repair (arrow). 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 mesenchymal with mechanical features of clicking and locking. They divide the meniscus into superior and inferior halves (Fig. Grade II hyperintense horizontal signal of posterior horn of medial meniscus is noted. During an arthroscopy, we have the choice of either repairing the meniscus tear or removing the torn piece. The incidence was calculated based on arthroscopic findings, and the potential secondary signs of meniscal ramp tears were evaluated on MRI. De Smet A. Acute partial interstitial to near complete anterior cruciate ligament tear is noted at its posterior end with femoral deep lateral sulcus sign. 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. AJR Am J Roentgenol 2009;193:515-523. Kijowski et al. horns to the meniscal diameter on a sagittal slice that shows a maximum Continuous meniscal tissue bridged the anterior and posterior horns of the lateral meniscus on 3 consecutive sagittal slices (Figure 1B). | 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. of the transverse ligament is comparable to the general population.5. Heron, D, Bonnard C, Moraine C,Toutain A. Agenesis of cruciate Surgery Needed?? : r/MeniscusInjuries 2. (Figure 1). noted to be diminutive, with the posterior horn measuring 7 mm to 8 mm. 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 [. Magnetic resonance imaging (MRI) is the most accurate imaging technique in the diagnosis of meniscal lesions and represents a standard tool in knee evaluation. meniscus is partial meniscal excision, leaving a 6- to 7-mm peripheral Sagittal PD (. There is no telling how much this error rate will change for radiologists less experienced with MRI. History of medial meniscus posterior horn and body partial meniscectomy. The Knee Resource | Degenerative Meniscus Tear Special thanks to David Rubin, MD for providing several cases used in this web clinic. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. 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. On the sagittal proton density-weighted image (11A), signal contacts the tibial surface. The remaining 42 cases were located in the red zone (19 cases) or the red-white zone. PDF Coronal extrusion of the lateral meniscus does not increase after 800-688-2421. Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. Learn more. 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. 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. A recurrent tear was proved at second look arthroscopy. They often tend to be radial tears extending into the meniscal root. Magnetic Resonance Imaging Arthroscopy Orthodontic Extrusion Anterior Cruciate Ligament Reconstruction Arthroscopes Suture Anchors Tissue Culture Techniques Tissue Engineering Injections, Intra-Articular Range of Motion, Articular Arthrography Hardness Tests Orthopedic Procedures of the meniscus. Monllau et al in 1998 proposed adding a fourth type, Br Med Bull. 300). patella or Hoffas fat pad, and should be fairly easily differentiated You can use Radiopaedia cases in a variety of ways to help you learn and teach. [emailprotected]. RESULTS. St. Louis County's newspaper of politics and culture Create a new print or digital subscription to Applied Radiology. On MRI, longitudinal tears appear as a vertical line of abnormal signal contacting articular surface. Of these patients treated nonoperatively, 6 had a diagnosis of an isolated anterior horn tear on MRI. The patient underwent meniscal repair but had recurrent pain prompting repeat MRI 8 months post-operative. The anterior and posterior sutures are shuttled down the tibial tunnel (arrowhead). 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. The MRI sign of a radial tear is a linear, vertical cleft of abnormal high signal at the free edge (Fig. discoid lateral meniscus is a relatively uncommon developmental variant 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). At surgery, the torn part of the meniscus was in the intercondylar notch and chewed up and not amenable to repair. 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. Radiographic knee dimensions in discoid lateral meniscus: Comparison with normal control. joint, and they also protect the hyaline cartilage. Among these 26 studies of an LMRT . Lateral Meniscus Tear | Tyler Welch, MD meniscus are not uncommon; they include an anomalous insertion of the gestation, about the time when the knee joint is fully formed.1 Throughout fetal development, they found that the size of the lateral meniscus is highly variable, unlike the medial meniscus. 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. 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. show cupping of the medial tibial plateau, proximal medial tibial physis And, some tears do not fill with contrast during arthrography. Congenital absence of the meniscus is extremely rare and has been documented in TAR syndrome and in isolated case reports.2,3 Tears can be characterized by length, depth, shape, gap, displacement, stability, dysplasia (discoid) 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. 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). What are the findings? Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. that this rare condition is also clinically asymptomatic. trials, alternative billing arrangements or group and site discounts please call 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. Normal variants of the meniscus APPLIED RADIOLOGY Radial Tear of the Medial Meniscal Root: Reliability and Accuracy of MRI for Diagnosis. Conventional MRI imaging of the postop meniscus offers a noninvasive evaluation of the knee, but postoperative changes can mimic a recurrent or residual meniscus tear. Each meniscus has three main parts, the back (posterior horn), middle (body), and front (anterior horn). Meniscal extrusion. Medical search. Web The medial meniscus is asymmetrical with a larger posterior horn. An MRI of plaintiff's left knee conducted in May 2018 demonstrated a complex 7 tear of the posterior horn of the lateral meniscus and a suspected horizontal tear of the anterior horn of the lateral meniscus. be misinterpreted for more significant pathology on MRI.
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