This emphasizes the importance of meniscal repair over meniscectomy when possible and the need for meniscal preservation when a partial meniscectomy is necessary. Most lateral meniscal tears are due to twisting or turning activities or falls. Type 1 is most common, and type Skeletal radiology. the menisci of the knees. For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. appearance.12 It is now believed that the knee develops from a The posterior root lies anterior to the posterior cruciate ligament. the posterior horn is usually much larger than the anterior horn (the There is a medial and a lateral meniscus. 800-688-2421. At second look arthroscopy, the posterior horn tear was healed and the anterior horn tear was found to be unstable and treated by partial meniscectomy. A meniscal allograft transplant frequently leads to significant improvements in pain and activity level and hastens the return to sport for most amateur and professional athletes.13 A common method of meniscal allograft transplant includes a cadaveric meniscus (fresh or frozen) attached by its anterior and posterior roots to a bone bridge with a trapezoidal shape harvested from a donor tibia. Following partial meniscectomy, the knee is at increased risk for osteoarthritis. The MRI sign of a radial tear is a linear, vertical cleft of abnormal high signal at the free edge (Fig. The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). 2019: Factors associated with bilateral discoid lateral meniscus tear in patients with symptomatic discoid lateral meniscus tear using MRi and X-ray Orthopaedics and Traumatology Surgery and Research: Otsr 105(7): 1389-1394 Another MRI was later performed due to worsening symptoms, and demonstrated a bucket-handle tear with complete anterior luxation of the posterior horn of the left lateral meniscus (Figs. Otherwise, the increased vascularity in children has sometimes led to false-positive reading of a meniscus tear. 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. What are the findings? Lateral meniscus bucket handle tears can produce the double anterior horn sign or double ACL sign. Interested in Group Sales? Radiographic knee dimensions in discoid lateral meniscus: Comparison with normal control. are reported cases of complete absence of the medial meniscus as Relevant clinical history, prior imaging and use of operative reports will significantly improve accuracy of post-operative interpretations. Discoid lateral meniscus. Vertical flap (oblique, flap, parrots beak) tears are unstable tears and occur in younger patients. normal knee. The superior, middle and inferior geniculate arteries are the main vascular supply to the menisci. to the base of the ACL or the intercondylar notch. During an arthroscopy, we have the choice of either repairing the meniscus tear or removing the torn piece. MRI of the knee is commonly indicated for evaluation of unresolved or recurrent knee pain following meniscal surgery. The example above illustrates marked degenerative changes caused by loss of meniscal function. Proper preoperative sizing of the allograft is critical for surgical success and usually performed with radiographs. Long-term outcome after arthroscopic meniscal repair versus arthroscopic partial meniscectomy for traumatic meniscal tears. At least one meniscofemoral ligament is present in 7093 % Of knees 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. immediatly lateral to the anterior horn of lateral meniscus and posterior to the tubercle of anteriro horn of medial meniscus . Thompson WO, Thaete FL, Fu FH, Dye SF. Sagittal T2-weighted image (18A) demonstrates high T2 fluid signal in the medial meniscus posterior horn consistent with a recurrent tear (arrow). 9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion. seen on standard 4- to 5-mm slices.21 The Wrisberg ligament may also be thick and high in patients with a complete discoid lateral meniscus.22 Other criteria used to diagnose lateral discoid meniscus include the following: In the discoid lateral meniscus, including a propensity for tears to occur and Radial or oblique tear congurations close to or within the meniscus . 2012;199(3):481-99. 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. MRIs of BHT may have several characteristic appearances including (1) fragment in the notch sign; (2) double anterior horn sign, in which there is an additional meniscal fragment in the anterior joint on top of the native anterior horn; (3) the absent bow tie sign; (4) the double PCL sign, in which the centrally displaced fragment lies just anterior and parallel to the PCL giving the appearance of two PCLs; and (5) the coronal truncation sign, in which the free edge of the meniscal body appears clipped off on coronal images (Fig. Medial meniscus posterior horn peripheral longitudinal tear treated with repair. sagittal magnetic resonance (MR) images. Sagittal proton density-weighted image (7A) through the medial meniscus demonstrates increased signal extending to the tibial surface (arrow). Anterior lateral cysts extended . Meniscal root tears are a form of radial tear that involves the central attachment of the meniscus (12a). Medial meniscus posterior horn peripheral longitudinal tear (arrow) seen on the sagittal proton density-weighted image (15A) and managed by repair. Learn more. {"url":"/signup-modal-props.json?lang=us"}, Weerakkody Y, Baba Y, Knipe H, et al. For DSR inquiries or complaints, please reach out to Wes Vaux, Data Privacy Officer, Shepard et al conclude that with a 74% false-positive rate, anterior horn tears should be treated surgically only if clinical correlation exists. We hope you found our articles For root tears in general, sagittal imaging may demonstrate a meniscal ghost sign. 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). On MR arthrography, (12B), gadolinium extends through the repair site indicating a tear. Lee, J.W. Posteroinferior displacement of the meniscal tissue (arrowheads) is also diagnostic of recurrent tear. How I Diagnose Meniscal Tears on Knee MRI. On imaging alone, the radiologist may not be able to distinguish a residual tear (failed repair) from a recurrent tear in the same location. They were first described by M J Pagnaniet al. 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. Both the healed peripheral tear and the new central tear were proved at second look arthroscopy. Pathology - a tear that has developed gradually in the meniscus. Definite surfacing signal or distortion on only one image represents a possible tear. 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. These findings are also frequently associated with genu It can be divided into five segments: anterior horn, anterior, middle and posterior segments, and posterior horn. (1A) Proton density-weighted, (1B) T2-weighted, and (1C) fat-suppressed T1-weighted MR arthrographic sagittal images are provided. 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. However, the use of MRI arthrography should be considered for post-operative menisci with equivocal findings on conventional MRI as the presence of high gadolinium-like signal within the meniscus would allow for a definitive diagnosis of re-tear. Partial meniscectomy is by far the most common procedure. runs from the anterior horn of the medial meniscus to either the ACL or There are 3 main types, according to the Watanabe classification:18. Extension to the anterior cortex of . In children, sometimes an increased signal is seen within meniscus due to increased vascularity, but usually the signal does not contact articular surface. On MRI, they resemble radial tears, with a linear cleft of abnormal signal seen at the free edge. Conventional MRI imaging correlates well with arthroscopic evaluation of the transplants for tears of the posterior and middle thirds of the meniscus allograft with a high sensitivity, specificity and accuracy, but results were poor for evaluation of the anterior third with a low specificity and accuracy.16 Allograft shrinkage and meniscus extrusion are common findings on postoperative MRI but do not always correlate with patient pain and function. MR criteria for discoid lateral menisci are used for discoid medial 2059-2066, Kinsella S.D., and Carey J.L. An intact meniscal repair was confirmed at second look arthroscopy. When evaluating a portion of the meniscus that is in a different location than the repair, criteria for evaluating a virgin meniscus may be used for that area. 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. meniscus is partial meniscal excision, leaving a 6- to 7-mm peripheral RESULTS. morphology. Sometimes T2 signal in a healed tear may look similar to fluid. 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). Get unlimited access to our full publication and article library. Methods Eighteen patients who had arthroscopically confirmed partial MMPRTs were included. This case features the following signs of meniscal tear: absent bow tie appearance of the lateral meniscus ghost meniscus: empty location of the anterior horn of the lateral meniscus Bilateral discoid medial menisci: Case report. 1427-143. Biologic augmentation with application of exogenous fibrin clot or growth factors may be combined with the repair to promote healing. in this case were attributed to an anterior cruciate ligament tear MRI Knee - Sagittal PDFS - Displaced meniscus Part of a torn meniscus can be displaced into another part of the knee joint In this image the anterior part of the meniscus (the anterior horn) is correctly located The posterior horn is displaced such that it is located next to the anterior horn The correct position of the posterior horn is shown These include looking for a Sagittal PD (. Nakajima T, Nabeshima Y, Fujii H, et al. Objective Parameniscal cysts have a very high association with meniscal tears in all locations except the anterior horn lateral meniscus (AHLM). CT arthrography may be used to evaluate the postoperative meniscus when MRI is contraindicated. There A tear of the lateral meniscus can occur from a sudden injury, or from chronic wear and overload. Lateral meniscus posterior horn peripheral longitudinal tear managed by repair. It is believed that discoid meniscal injury. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. Type High signal close to fluid intensity contacts the tibial surface on the sagittal T2-weighted image (11B) and is equivocal. On MRI, they exhibit abnormal horizontal linear signal contacting the inferior articular surface near the free edge or less commonly the superior surface. AJR American journal of roentgenology. 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. Sagittal T2-weighted image (10B) reveals no fluid at the repair site. Irrespective of the repair approach or repair devices used, diagnostic criteria for a recurrent tear remains the same fluid signal or contrast extending into the meniscal substance. Symptomatic anomalous insertion of the medial meniscus. small meniscus is also seen in the wrist joint. Also, the inferior patella plica inserts on the At 1 year, 5 of 6 were completely asymptomatic with the remaining patient minimally painful with no suggestion of meniscal symptoms. Normal Grade 3 is a true meniscus tear and an arthroscope is close to 100 percent accurate in diagnosing this tear.