MRI showed posterior horn of the medial meniscus (PHMM) horizontal tear with early degenerative changes. 2012;20(10):2098-103. ligaments are absent, most commonly the anterior cruciate ligament (ACL) Meniscal disorders: Normal, discoid, and cysts. 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. Kocher MS, Klingele K, Rassman SO. An abnormal shape may indicate a meniscal tear or a partial meniscectomy. 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. Most lateral meniscal tears are due to twisting or turning activities or falls. The meniscal body is firmly attached to the deep portion of the medial collateral ligament complex via the meniscotibial ligament. Imaging characteristics of the A 64-year-old female with no specific injury presented with knee pain, swelling, and locking that she first noticed after working out at the gym. Lateral meniscal variant with absence of the posterior coronary ligament. The MRI revealed a longitudinal tear in the posterior horn of the lateral meniscus. ligaments and menisci causing severe knee dysplasia in TAR syndrome. Renew or update your current subscription to Applied Radiology. Conventional MRI is useful for evaluation of posterior root morphology at the tibial tunnel fixation site, meniscal extrusion and articular cartilage. morphology but lacks its posterior attachments; ie, the meniscotibial There [emailprotected]. Am J Sports Med 2017; 45:4249, ElAttar M, Dhollander A, Verdonk R, Almqvist KF, Verdonk P. Twenty six years of meniscal allograft transplantation: is it still experimental? reported.4. 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 ]. The posterior root of the lateral meniscus (PRLM) attaches along the posterior aspect of the intercondylar eminence of the tibia (Fig. varus deformity (Figure 3). 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 [. 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 . Meniscal root tear. The condition is typically asymptomatic and, therefore, is infrequently diagnosed.14 Tears . At the time the case was submitted for publication Mostafa El-Feky had no recorded disclosures. Both the healed peripheral tear and the new central tear were proved at second look arthroscopy. Sagittal proton density-weighted image (6A) through the medial meniscus following partial meniscectomy and debridement of the inferior articular surface shows increased PD signal contacting the inferior articular surface (arrow) but no T2 fluid signal at the surgical site (6B) and no gadolinium signal in the meniscus (6C). 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. menisci occurs. Horizontal (degenerative) tears run relatively parallel the tibial plateau. 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. 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. 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. A displaced longitudinal tear is a "bucket handle" tear. small meniscus is also seen in the wrist joint. hypoplastic meniscus was not the cause of the patients pain, suggesting However, the tear changes plane of orientation over its course. The torn edges are aligned, and stable fixation applied with sutures or bioabsorbable implants at approximately 5 mm intervals. MR imaging evaluation of the postoperative knee. Tears in the red zone have the potential to heal and are more amenable to repair. 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 ]. 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. Arthroscopy evaluation found a lateral meniscus peripheral (red-white zone) longitudinal tear. Meniscal root tears are a form of radial tear that involves the central attachment of the meniscus (12a). the intercondylar notch, most commonly to the mid ACL, and less commonly The patient subsequently underwent successful partial medial meniscectomy. Of these patients treated nonoperatively, 6 had a diagnosis of an isolated anterior horn tear on MRI. CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. Kijowski et al. Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. Anomalous RESULTS. Rohren EM, Kosarek FJ, Helms CA. FSE T2-weighted images, with a slab-like appearance on coronal images. Mechanical rasping or trephination of the torn meniscus ends and parameniscal synovium is used to promote bleeding and vascular healing. This injury is biomechanically comparable to a total meniscectomy, leading to compromised hoop stressesresulting in decreased tibiofemoral contact area and increased contact pressures in the involved compartment.These changes are detrimental to the articular cartilage and . Magnetic resonance imaging (MRI) revealed an elongated free edge of the diffusely enlarged lateral meniscus extending toward the intercondylar region on coronal T1-weighted images (Figure 1A). 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). 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. Pathology - a tear that has developed gradually in the meniscus. Intensity of signal contacting meniscal surface in recurrent tears on MR arthrography compared with that of contrast material. Biologic augmentation with application of exogenous fibrin clot or growth factors may be combined with the repair to promote healing. This scan showed a radial MMT. Lee, J.W. Collagen fibers are arranged for transferring compressive loads into circumferential hoop stresses, secured by radially oriented tie fibers. 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 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 Normal course and intensity of both cruciate ligaments. tissue only persists at the edges, where differentiation into the meniscus are not uncommon; they include an anomalous insertion of the Most horizontal tears extend to the inferior articular surface. 2005; 234:5361. This is a critical differentiation because the latter represents meniscal tears that can be The superior, middle and inferior geniculate arteries are the main vascular supply to the menisci. There is no universally accepted system for classifying meniscal tear patterns. medial meniscus, discoid lateral meniscus, including the Wrisberg They are usually due to an acute injury [. To provide the highest quality clinical and technology services to customers and patients, in the spirit of continuous improvement and innovation. The patient failed conservative management of aspiration and cortisone injection. The self-reported complication rate for partial meniscectomy is 2.8% and meniscus repair is 7.6%. They may not even be apparent with an arthroscopic examination. In this case the roots remained intact at the bone bridge, but the meniscal allograft detached from the joint capsule at the posterior and middle third with displacement into the central weightbearing surface (arrowheads) on sagittal T2-weighted (17C) and fat-suppressed axial proton density-weighted (17D) images. Discoid medial menisci are much less common than discoid lateral menisci,24 and they may be bilateral. MRI has high sensitivity and specificity for detecting meniscus tears in patients without prior knee surgery. Radial or oblique tear congurations close to or within the meniscus . Sagittal proton density-weighted image (9A) demonstrates no high signal abnormality. The meniscus root plays an essential role in maintaining the circumferential hoop tension and preventing meniscal displacement. trials, alternative billing arrangements or group and site discounts please call The posterior root of the medial meniscus attaches to the tibia, just anterior and medial to the posterior cruciate ligament (PCL). MRI c spine / head jxn - they can have stenosis of foramen magnum . 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. Meniscus tears, indicated by MRI, are classified in three grades. 7.2 Medial and Lateral Menisci Medial meniscus is larger than the lateral meniscus and is more "open" (=less C-like) and less wide. 17. of the anterior horn of the medial meniscus, an inferior patella plica, pretzels dipped in sour cream. You can use Radiopaedia cases in a variety of ways to help you learn and teach. Normal the posterior horn is usually much larger than the anterior horn (the 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 A previous study by De Smet et al. They often tend to be radial tears extending into the meniscal root. The anterior root of the lateral meniscus attaches to the tibia, just lateral to the midline and posterior to fibers of the anterior cruciate ligament (ACL). congenital anomalies affect the lateral meniscus, most commonly a problem in practice. Also, the inferior patella plica inserts on the menisci develop from this mesenchymal tissue in a site where this tissue measurements of the posterior horn of the medial meniscus may vary, but as at no time in development does the meniscus have a discoid As a result, the accuracy rate of diagnosis by MRI is 83.3%. The meniscal repair is intact. 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 MR arthrography, (12B), gadolinium extends through the repair site indicating a tear. Pagnani M, Cooper D, Warren R. Extrusion of the Medial Meniscus. 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. Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. Arthroscopy for Medial Meniscus Tears The decision to repair or remove the torn portion is made at the time of surgery. However, many clinicians opt to use conventional MRI as the initial postoperative imaging study and reserve MR arthrography for equivocal cases. What are the findings? 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. Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation. Check for errors and try again. Type Examination of the knee showed a mild effusion, 1+ Lachman, positive Pivot shift, and mild tenderness to both medial and lateral joint lines. 2014; 43:10571064, McCauley TR. 36 year old male with history of meniscus surgery 7 years ago. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. Shepard and colleagues at UCLA specifically analyzed this by reviewing 947 consecutive MRIs. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. Kim EY, Choi SH, Ahn JH, Kwon JW. In cases like this, MR arthrography is quite helpful. The meniscus can separate from the joint capsule or tear through the allograft. Tears can be characterized by length, depth, shape, gap, displacement, stability, dysplasia (discoid) Sagittal proton density-weighted image (10A) demonstrates increased signal extending to the articular surface consistent with granulation tissue. The most common Repair techniques include inside-out, outside-in or all-inside approaches. If missing on MR images, a posterior root tear is present. On examination, the patient had medial joint line tenderness with positive McMurray test. Report The MRI showed complete ACL tear with displaced bucket handle medial meniscus tear. This case is almost identical to the previous case with a different clinical history. 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. 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. proximal medial tibia was convex and the distal medial femoral condyle 5 In the first instance, tears of the lateral aspect of the anterior horn of the medial meniscus are extremely uncommon and should not be a diagnostic In children, sometimes an increased signal is seen within meniscus due to increased vascularity, but usually the signal does not contact articular surface. Create a new print or digital subscription to Applied Radiology. 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. The medial meniscus covers 60% of the medial compartment. Pinar H, Akseki D, Karaoglan O, et al. Root tears are associated with a high risk for osteoarthritis. The LaPrade classification systemof meniscal root tears has become commonly used in arthroscopy, and there is evidence that this system can be to some extent translated to MRI assessment of these tears ref. Nakajima T, Nabeshima Y, Fujii H, et al. A Type 1 is most common, and type Brody J, Lin H, Hulstyn M, Tung G. Lateral Meniscus Root Tear and Meniscus Extrusion with Anterior Cruciate Ligament Tear. 300). Symptoms of anterior horn tears were very similar to those of meniscal tears of the midbody or posterior horn, including catching, pain with knee flexion, and swelling. Repair techniques include side-to-side repair, stabilization with suture anchors, and the transtibial pull-out technique (figure 4).12. 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. Volunteerism and Sports Medicine: Where do We Stand? 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. pivoting). 2008;191(1):81-5. Analytical, Diagnostic and Therapeutic Techniques and Equipment 13. At the time the article was last revised Yahya Baba had It is located in the lateral portion of the knee interior of the knee joint. The posterior root lies anterior to the posterior cruciate ligament. There are 3 main types, according to the Watanabe classification:18. 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. 2006;239(3):805-10. Problems encountered in a discoid medial meniscus are the same as a This is a well-done study with clinical correlation and adequate follow-up. to tear. Menisci are present in the knees and the On MRI, they exhibit abnormal horizontal linear signal contacting the inferior articular surface near the free edge or less commonly the superior surface. If the tear does not show, it is considered a Grade 1 or 2 and is not as serious. Indications for meniscal repair typically include posttraumatic peripheral (red zone) longitudinal tears located near the joint capsule, ideally in younger patients (less than 40). 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 . 2012;199(3):481-99. horn of the lateral meniscus, and oblique tear orientation In the present study, the patients analyzed came from the have been the most difficult for imaging planes to visualize same geographical area . Menisci ensure normal function of the Monllau et al in 1998 proposed adding a fourth type, It is believed that discoid Discoid lateral meniscus of the knee joint: Nature, mechanism, and operative treatment. Neuschwander DC, Drez D Jr, Finney TP. Is sport activity possible after arthroscopic meniscal allograft transplantation? (Figure 1). Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window), Click to share on Google+ (Opens in new window), Posterior Instability and Labral Pathology, Imaging Evaluation of the Painful or Failed Shoulder Arthroplasty, Other Entities: PLRI, HO, Triceps, and Plica, MRI-Arthroscopy Correlations in the Overhead Athlete, Acetabular Fossa, Femoral Fovea, and the Ligamentum Teres. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. Semin Musculoskelet Radiol 2005;9(2):11624, Chung KS, Ha JK, Ra HJ, Nam GW, Kim JG. 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 2008; 32:212219, Magee T. Accuracy of 3-Tesla MR and MR arthrography in diagnosis of meniscal retear in the post-operative knee. asymptomatic, although there is a greater propensity for discoid menisci 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. Increased intrameniscal signal is commonly seen in the transplanted allograft but does not correlate with clinical outcome. Klingele KE, Kocher MS, Hresko MT, et al. Become a Gold Supporter and see no third-party ads. Skeletal radiology. Clin Orthop Relat Res 2013; 471: pp. A recurrent tear was proved at second look arthroscopy. It splits into two bands at the PCL, named Humphry(anterior to the PCL) and Wrisberg (posterior to the PCL). Grade 3 is a true meniscus tear and an arthroscope is close to 100 percent accurate in diagnosing this tear. A tear of the meniscal root means the tear is near where it attaches to the bone, usually far in the back. Surgical Outcomes Lysholm Score 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. of the AIMM into the ACL is classified as Type 1 (inferior third), Type 2 Most studies have shown increased accuracy for direct and indirect MR arthrography compared to conventional MRI for partial meniscectomies of 25% or more.16. The ideal technique for imaging the postoperative meniscus is a matter of active controversy and depends on the operation performed, surgeon preference and clinical question (concern for recurrent meniscal tear versus articular cartilage). 1). 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. 2020;49(1):42-49. Meniscal root tears are defined as radial tears located within 1 cm from the meniscal attachment or a bony rootavulsion. Anterior lateral cysts extended . History of a longitudinal medial meniscus tear managed by repair and concurrent ACL reconstruction. There is no telling how much this error rate will change for radiologists less experienced with MRI. Objective Parameniscal cysts have a very high association with meniscal tears in all locations except the anterior horn lateral meniscus (AHLM). MR imaging is useful for evaluation of many possible complications following meniscal surgery. The anomalous insertion Intact meniscal roots. The speckled appearance of the anterior horn of lateral meniscus is a feature that can be seen as a normal variant on MRI knee scans. Discoid lateral meniscus was originally believed to result from an They were first described by M J Pagnaniet al. Acute partial interstitial to near complete anterior cruciate ligament tear is noted at its posterior end with femoral deep lateral sulcus sign. least common is complete congenital absence of the menisci. Meniscal tears were found on MRI or arthroscopy in all 28 patients with a lateral cyst overlying the body or posterior horn of the lateral meniscus, whereas a tear was found on MRI or arthroscopy in only 14 (64%) of 22 patients with cysts adjacent to or extending to the lateral meniscus anterior horn (p = 0.006). According to one source, they are thought to account for ~10% of all arthroscopic meniscectomies 5. | 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. The intrameniscal ligament where it diverges from the back of the anterior horn of the lateral meniscus is also a common area misinterpreted as a tear. Anterior tibial marrow edema and organized trabecular fracture measuring 16 mm AP, 18 mm transverse. meniscal diameter. However, few studies have directly compared the medial and lateral root tears. Discoid lateral meniscus. History of longitudinal medial meniscus tear managed by meniscal repair (arrows). bilaterally absent menisci reported by Tolo et al,3 the We will review the common meniscal variants, which 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. trauma; however, other symptoms include clicking, snapping, and locking The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). Pre-operative fat supressed coronal proton density-weighted image (19A) demonstates a posterior root radial tear (arrow). 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. High signal close to fluid intensity contacts the tibial surface on the sagittal T2-weighted image (11B) and is equivocal. The camera can visualize the meniscus and other structures within the knee. Source: Shepard MF, et al. 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. American Board of Orthopaedic Surgery Practice of the Orthopaedic Surgeon: Part-II, certification examination case mix. (as previously described), meniscal cyst,26 discoid lateral meniscus in the same knee (Figure 9),25 and pathologic medial patella plica.27. MR criteria are used to make the diagnosis. On this page: Article: Epidemiology Pathology Radiographic features History and etymology The examiner can test the entire posterior horn up to the middle segment of the meniscus using the IR of the tibia followed by an extension. Ideal for residents, practicing radiologists, and fellows alike, this updated reference offers easy-to-understand guidance on how to approach musculoskeletal MRI and recognize abnormalities. 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. It is important to know the age of the patient when interpreting the MRI. Arthroscopy revealed a horizontal tear of PHMM, and a partial medial meniscectomy was performed. Normal The same imaging criteria (as for the case of greater than 25% partial meniscectomy), the presence of fluid signal on T2-weighted or contrast extending into the meniscal substance is used to diagnose a recurrent tear. Magnetic resonance imaging (MRI), was performed in another facility and, showed normal medial and lateral menisci except for the absence of a medial posterior root insertion both on coronal and on sagittal images. A meniscus is a crescent-shaped fibrocartilaginous structure that 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. ligament will help to exclude these conditions.5 In the first 2a, 2b, 2c). 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.