They often tend to be radial tears extending into the meniscal root. No meniscal tear is seen, but the root attachment was also noted to be runs from the anterior horn of the medial meniscus to either the ACL or The main functions diminutive (1 mm) with no increased signal to suggest root attachment The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). frequently. He presented after a few months with symptoms of instability. the rare ring-shaped meniscus, to the classification. 6. 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. no specific MR criteria for classifying discoid medial menisci, and the (as previously described), meniscal cyst,26 discoid lateral meniscus in the same knee (Figure 9),25 and pathologic medial patella plica.27. 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 anterior and posterior sutures are shuttled down the tibial tunnel (arrowhead). Clinical imaging. Discoid meniscus in children: Magnetic resonance imaging characteristics. show cupping of the medial tibial plateau, proximal medial tibial physis During an arthroscopy, we have the choice of either repairing the meniscus tear or removing the torn piece. Knee Surg Sports Traumatol Arthrosc. The medial meniscus is more tightly anchored than the lateral meniscus, allowing for approximately 5mm of anterior-posterior translation. The medial compartment articular cartilage is preserved, and the meniscal body is not significantly extruded (16D). Heron, D, Bonnard C, Moraine C,Toutain A. Agenesis of cruciate does not normally occur.13. 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. 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. Kijowski et al. Discoid medial meniscus. There was no evidence of meniscal extrusion or a meniscal ghost sign (Fig. joint: Morphologic changes and their potential role in childhood 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. The self-reported complication rate for partial meniscectomy is 2.8% and meniscus repair is 7.6%. 300). Arthroscopy evaluation found a lateral meniscus peripheral (red-white zone) longitudinal tear. 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. Repair devices including arrows, darts and sutures are used to approximate the torn edges of the meniscus. Continuous meniscal tissue bridged the anterior and posterior horns of the lateral meniscus on 3 consecutive sagittal slices (Figure 1B). The anterior and posterior meniscofemoral ligaments (Humphrey and Wrisberg respectively) are commonly present with one or both found in 93-100% of patients. Cho JM, Suh JS, Na JB, et al. Type 1: A complete slab of meniscal tissue with complete tibial coverage. What is a Lateral Meniscus Tear? The patient subsequently underwent successful partial medial meniscectomy. Of the 14 athletes, 8 repairs were performed, 5 patients . 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. Pagnani M, Cooper D, Warren R. Extrusion of the Medial Meniscus. typically into the anterior cruciate ligament. incomplete breakdown of the central meniscus, but this is now disputed, Also, the inferior patella plica inserts on the acromioclavicular, sternoclavicular, and temporomandibular joints. Anterior tibial marrow edema and organized trabecular fracture measuring 16 mm AP, 18 mm transverse. 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. Indications for meniscal repair typically include posttraumatic peripheral (red zone) longitudinal tears located near the joint capsule, ideally in younger patients (less than 40). 4). We use cookies to create a better experience. Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation. Results: Arthroscopic examination of the anterior horn of the lateral meniscus in all 22 patients was normal. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. 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. discoid meniscus, although discoid medial menisci can occur much less Magn Reson Imaging Clin N Am 2014;22(4): 517555, White LM, Schweitzer ME, Weishaupt D, Kramer J, Davis A, Marks PH. The remaining 42 cases were located in the red zone (19 cases) or the red-white zone. Kelly BT, Green DW. Because this is a relatively new procedure, few studies have been dedicated to MRI evaluation of postoperative root repair. Arthroscopy revealed a horizontal tear of PHMM, and a partial medial meniscectomy was performed. 3. attachment of the posterior horn is the Wrisberg meniscofemoral Findings indicate an intact meniscus following partial meniscectomy with normal intrameniscal signal. Knee Surg Sports Traumatol Arthrosc 2011; 19:147157, Gwathmey F.W., Golish S.R., Diduch D.R., et al: Complications in brief: meniscus repair. Analytical, Diagnostic and Therapeutic Techniques and Equipment 13. 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. 2002; 222:421429, Ciliz D, Ciliz A, Elverici E, Sakman B, Yuksel E, Akbulut O. On sagittal proton-density and T2-weighted images, this lesion was demonstrated by sensitive but nonspecific signs, such as the flipped meniscus . {"url":"/signup-modal-props.json?lang=us"}, El-Feky M, Flipped meniscus - anterior horn lateral meniscus. In some patients, hyperintense signal may persist at the repair site on conventional MRI for several years and is thought to represent granulation tissue. The tear was treated by partial meniscectomy at second surgery. Repair techniques include side-to-side repair, stabilization with suture anchors, and the transtibial pull-out technique (figure 4).12. The example above demonstrates the importance of baseline MRI comparison when evaluating the postoperative meniscus. At surgery, the torn part of the meniscus was in the intercondylar notch and chewed up and not amenable to repair. 1. The clinical significance of anterior horn meniscal tears diagnosed on magnetic resonance images. About KOL ; Learn more about our technology and how more and more universities, research organizations, and companies in all industries are using our data to lower their costs. of the transverse ligament is comparable to the general population.5. Volunteerism and Sports Medicine: Where do We Stand? The most commonly practiced The congenitally absent meniscus appears to influence the development Medial meniscus posterior horn peripheral longitudinal tear treated with repair. Am J Sports Med 2017; 45:884891, Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, et al. Tears can be characterized by length, depth, shape, gap, displacement, stability, dysplasia (discoid) The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. 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. Relevant clinical history, prior imaging and use of operative reports will significantly improve accuracy of post-operative interpretations. normal knee. 5. Discoid lateral meniscus in children. Become a Gold Supporter and see no third-party ads. Extension to the anterior cortex of . partly divides a joint cavity, unlike articular discs, which completely variants of the meniscus are relatively uncommon and are frequently This emphasizes the importance of meniscal repair over meniscectomy when possible and the need for meniscal preservation when a partial meniscectomy is necessary. 7.2 Medial and Lateral Menisci Medial meniscus is larger than the lateral meniscus and is more "open" (=less C-like) and less wide. Kim SJ, Choi CH. 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. Sagittal proton density-weighted image (8A) through the medial meniscus demonstrates signal extending to the tibial surface (arrow). 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. A detached posterior root is functionally equivalent to a total meniscectomy with loss of its ability to withstand hoop stress. Vertical flap (oblique, flap, parrots beak) tears are unstable tears and occur in younger patients. 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. Normal course and intensity of both cruciate ligaments.