AJR Am J Roentgenol 2009;193:515-523. pivoting). MRI appearance of Wrisberg variant of discoid lateral meniscus. Longitudinal lateral meniscus tear status post repair (arrow). that this rare condition is also clinically asymptomatic. patella or Hoffas fat pad, and should be fairly easily differentiated 2002; 222:421429, Ciliz D, Ciliz A, Elverici E, Sakman B, Yuksel E, Akbulut O. this may extend to to the mid body." is this a bucket tear? Shepard et al have done a nice job of telling us just how frequently this mistake can be made by fellowship trained musculoskeletal radiologists. structure on sagittal images on T1, proton density, and fat-saturated 9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion. Extension to the anterior cortex of . Associated anomalies in a discoid medial On MRI, they resemble radial tears, with a linear cleft of abnormal signal seen at the free edge. The self-reported complication rate for partial meniscectomy is 2.8% and meniscus repair is 7.6%. noted to be diminutive, with the posterior horn measuring 7 mm to 8 mm. One important reason for such discrepancies is a failure to understand the transverse geniculate ligament of the knee (TGL). 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. Weight-bearing knee X-rays showed a 50 % narrowing in the medial compartment. An athletic 52-year-old male, who was an avid runner all his adult life, presented with medial pain and a popping sensation in knee. MRI of the knee is commonly indicated for evaluation of unresolved or recurrent knee pain following meniscal surgery. . Normal menisci. Both the healed peripheral tear and the new central tear were proved at second look arthroscopy. 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 . MR imaging and MR arthrography for diagnosis of recurrent tears in the postoperative meniscus. Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation. It is often explained by fibers of the anterior cruciate ligament and the covering synovium . 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. Magnetic resonance imaging of the postoperative meniscus: resection, repair, and replacement. Meniscal surgery is common and requires accurate post-operative imaging interpretation to guide the treatment approach. insertion of the medial meniscus (AIMM) has been described, and it is He presented after a few months with symptoms of instability. The lateral meniscus is produced by the varus tension and tibial IR. Discoid lateral meniscus and the frequency of meniscal tears. 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. Figure 8: Medial oblique menisco-meniscal . 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. As a result, the accuracy rate of diagnosis by MRI is 83.3%. 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. posterior horn of the medial meniscus include a triangular hypointense Dr. Michael Gabor answered Diagnostic Radiology 35 years experience No,: It doesn't sound like a bucket handle tear Extrusion is commonly seen following root repair. Because this is a relatively new procedure, few studies have been dedicated to MRI evaluation of postoperative root repair. Radiology. Sagittal proton density-weighted image (7A) through the medial meniscus demonstrates increased signal extending to the tibial surface (arrow). The example above demonstrates the importance of baseline MRI comparison when evaluating the postoperative meniscus. Sagittal proton density-weighted image (8A) through the medial meniscus demonstrates signal extending to the tibial surface (arrow). The reported prevalence is 0.06% to 0.3%.25 A previous study by De Smet et al. Long-term outcome after arthroscopic meniscal repair versus arthroscopic partial meniscectomy for traumatic meniscal tears. 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. 2. The insertion site Arthroscopy evaluation found a lateral meniscus peripheral (red-white zone) longitudinal tear. Kim EY, Choi SH, Ahn JH, Kwon JW. Tear between 1-4 cm vertical tear red-red meniscal root <40 yo Maybe concominant ACL surgery . 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. Collagen fibers are arranged for transferring compressive loads into circumferential hoop stresses, secured by radially oriented tie fibers. 17. The most widely used diagnostic modalities to assess the ligament injuries are arthroscopy and Magnetic Resonance Imaging (MRI). partly divides a joint cavity, unlike articular discs, which completely Stein T, Mehling AP, Welsch F, von EisenhartRothe R, Jger A. Also, the inferior patella plica inserts on the Dr. Diduch, Associate Professor, Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA, is Editor of Sports Medicine Reports. in this case were attributed to an anterior cruciate ligament tear Direct intraarticular injection of 20-50 mL of dilute iodinated contrast is performed with rapid image acquisition using multidetector CT with high spatial resolution and multiplanar reformatted images. 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 . 800-688-2421. 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. 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. of the menisci can be summarized as providing: Clark and Ogden studied the natural development of the menisci in the no specific MR criteria for classifying discoid medial menisci, and the Discoid lateral meniscus was originally believed to result from an They may not even be apparent with an arthroscopic examination. In this case, we can determine that there is a new tear in a different location. After failing conservative management with NSAIDs, PT, and activity modification, he underwent an MRI. 2012;20(10):2098-103. View Mostafa El-Feky's current disclosures, see full revision history and disclosures, Flipped meniscus - anterior horn lateral meniscus, Disproportionate posterior horn sign (meniscal tear). FSE T2-weighted images, with a slab-like appearance on coronal images. Thirty-one of these patients underwent subsequent arthroscopic evaluation to allow clinical correlation. of the AIMM into the ACL is classified as Type 1 (inferior third), Type 2 Pre-operative fat supressed coronal proton density-weighted image (19A) demonstates a posterior root radial tear (arrow). CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. Kijowski et al. Get unlimited access to our full publication and article library. These features constitute O'Donoghue unhappy triad. In the U.S., intraarticular injection of gadolinium-based contrast is off label. Continuous meniscal tissue bridged the anterior and posterior horns of the lateral meniscus on 3 consecutive sagittal slices (Figure 1B). 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. 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. 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. (Tr. What is your diagnosis? Arthroscopy revealed a horizontal tear of PHMM, and a partial medial meniscectomy was performed. The posterior root of the lateral meniscus (PRLM) attaches along the posterior aspect of the intercondylar eminence of the tibia (Fig. The MRI revealed a longitudinal tear in the posterior horn of the lateral meniscus. Financial Disclosure: None of the authors or planners for this educational activity have relevant financial relationships to disclose with ineligible companies whose primary business is producing, marketing, selling, reselling, or distributing healthcare products used by or on patients. Media community. variants of the meniscus are relatively uncommon and are frequently What is a Lateral Meniscus Tear? If a meniscus tear shows up on a MRI, it is considered a Grade 3. normal knee. The patient failed conservative management of aspiration and cortisone injection. On examination, there was marked medial joint line tenderness and a large effusion. Because there is less pressure on the meniscus there, it is difficult to evaluate the anterior region of the meniscus. The lateral meniscus is one of two fibrocartilaginous menisci of the knee. The symptoms 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. Diagnosis of recurrent meniscal tears: prospective evaluation of conventional MR imaging, indirect MR arthrography, and direct MR arthrography. The most commonly practiced Complex or deep radial tears were found in three of five cases of lateral meniscus extrusion and normal root. Lateral meniscus extrusion was present in six (23%) of 26 LMRTs and five (2.2%) of 231 patients with normal meniscus roots ( P < .001). They often tend to be radial tears extending into the meniscal root. The patient underwent a successful partial medial meniscectomy and was encouraged to seek low-impact exercise. 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. Source: Shepard MF, et al.