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). 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). discoid meniscus, although discoid medial menisci can occur much less On sagittal proton-density and T2-weighted images, this lesion was demonstrated by sensitive but nonspecific signs, such as the flipped meniscus . Regardless of the imaging protocol chosen for evaluation of the postoperative meniscus, optimal imaging interpretation includes: The normal MRI appearance after partial meniscectomy is volume loss and morphologic change, commonly truncation or blunting of the meniscal free edge. Become a Gold Supporter and see no third-party ads. . On MR images of the knee it is sometimes impossible to determine with confidence if a focus of high signal in the meniscus is confined to the substance of the meniscus or if it extends to involve the surface. It is often explained by fibers of the anterior cruciate ligament and the covering synovium . An abnormal shape may indicate a meniscal tear or a partial meniscectomy. Discoid lateral meniscus and the frequency of meniscal tears. You have reached your article limit for the month. 2008;191(1):81-5. When bilateral, they are usually symmetric. > 20% ratio of meniscus to tibia on the coronal image; Minimum diameter 14-15 mm on a midcoronal image; 75% Recent evidence suggests that decreased extrusion may correlate to better clinical outcomes.18. [emailprotected]. 2020;49(1):42-49. 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. 1. For information on new subscriptions, product 2006; 187:W565568. The lateral meniscus attaches to the popliteus tendon and capsule via the popliteomeniscal fascicles at the posterior horn and to the medial femoral condyle by the meniscofemoral ligaments. Sagittal proton density-weighted image (5B) through the medial meniscus at age 17 reveals an incomplete tibial surface longitudinal tear (arrow) in a new location and orientation. does not normally occur.13. slab-like configuration on sagittal MR images, with > 3 bowties {"url":"/signup-modal-props.json?lang=us"}, El-Feky M, Flipped meniscus - anterior horn lateral meniscus. 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. Kim SJ, Choi CH. Reporting knee meniscal tears: technical aspects, typical pitfalls and continued knee pain after meniscus surgery tissue only persists at the edges, where differentiation into the Brody J, Lin H, Hulstyn M, Tung G. Lateral Meniscus Root Tear and Meniscus Extrusion with Anterior Cruciate Ligament Tear. Atypically thick and high location 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. appearance.12 It is now believed that the knee develops from a ligaments and menisci causing severe knee dysplasia in TAR syndrome. However, this conjecture and others pre- highest.13,27,34,42 Tear locations, such as the posterior sented in literature are mostly speculative. bilaterally absent menisci reported by Tolo et al,3 the 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. Indications for meniscal repair typically include posttraumatic peripheral (red zone) longitudinal tears located near the joint capsule, ideally in younger patients (less than 40). Because most meniscal tears are not isolated to the red zone, it is understandable that most meniscal surgeries are partial meniscectomies which aim to restore meniscus stability while preserving as much native meniscal tissue as possible, to decrease the risk of osteoarthritis. We hope you found our articles The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. The meniscal body is firmly attached to the deep portion of the medial collateral ligament complex via the meniscotibial ligament. Reference article, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-40036, {"containerId":"expandableQuestionsContainer","displayRelatedArticles":true,"displayNextQuestion":true,"displaySkipQuestion":true,"articleId":40036,"questionManager":null,"mcqUrl":"https://radiopaedia.org/articles/meniscal-root-tear/questions/1112?lang=us"}. Stein T, Mehling AP, Welsch F, von EisenhartRothe R, Jger A. Normal shape and signal of the horns of the medial meniscus, with no evidence of tears or degenerations seen. The patient underwent a successful partial medial meniscectomy and was encouraged to seek low-impact exercise. 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 . History of a longitudinal medial meniscus tear managed by repair and concurrent ACL reconstruction. Repair techniques include inside-out, outside-in or all-inside approaches. Clinical Examination in the Diagnosis of Anterior Cruciate : JAAOS Lateral Meniscus Tear | New Health Advisor 17. 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. Radiographic knee dimensions in discoid lateral meniscus: Comparison with normal control. Kim EY, Choi SH, Ahn JH, Kwon JW. Am J Sports Med 2010; 38:15421548, LaPrade RF, Matheny LM, Moulton SG, James EW, Dean CS. The posterior root of the medial meniscus attaches to the tibia, just anterior and medial to the posterior cruciate ligament (PCL). They often tend to be radial tears extending into the meniscal root. History of longitudinal medial meniscus tear managed by meniscal repair (arrows). Arthroscopy revealed a horizontal tear of PHMM, and a partial medial meniscectomy was performed. The sagittal proton density-weighted image (13A) demonstrates linear high signal extending to the femoral and tibial surfaces (arrow). Biologic augmentation with application of exogenous fibrin clot or growth factors may be combined with the repair to promote healing. They were first described by M J Pagnaniet al. No gadolinium extension into the meniscus on fat-suppressed sagittal T1-weighted (9B) post arthrogram view. Lateral meniscus extrusion was present in six (23%) of 26 LMRTs and five (2.2%) of 231 patients with normal meniscus roots ( P < .001). . Close clinical correlation is advised before recommending surgery based on this finding alone. congenital absence of the cruciate ligaments. 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. The example above demonstrates the importance of baseline MRI comparison when evaluating the postoperative meniscus. separate the cavity. Imaging characteristics of the 70 year-old female with history of medial meniscus posterior horn radial tear. Footballer's Lateral Meniscus: Anterior Horn Tears of the Lateral Examination of the knee showed a mild effusion, 1+ Lachman, positive Pivot shift, and mild tenderness to both medial and lateral joint lines. 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. In morphology but lacks its posterior attachments; ie, the meniscotibial tear. Radiology. Connolly B, Babyn PS, Wright JG, Thorner PS. Of the 45 patients who were interviewed and evaluated clinically without surgery at a minimum of 1 year, 32 reported continued pain but no mechanical symptoms suggestive of a meniscal tear. Radial Meniscal Tear: Pearls May be degenerative or traumatic, vertical, millimeters in size, on the inner edge of the lateral meniscus more commonly than the medial meniscus acromioclavicular, sternoclavicular, and temporomandibular joints. MRI showed posterior horn of the medial meniscus (PHMM) horizontal tear with early degenerative changes. Pain is typically medial and activity-related (e.g. Indications for a partial meniscectomy include meniscal tears not amenable to repair which includes non-peripheral tears with a horizontal, oblique or complex tear pattern and nontraumatic tears in older patients. occur with minor trauma. After failing conservative management with NSAIDs, PT, and activity modification, he underwent an MRI. 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 ]. Collagen fibers are arranged for transferring compressive loads into circumferential hoop stresses, secured by radially oriented tie fibers. FSE T2-weighted images, with a slab-like appearance on coronal images. The anterior root of the medial meniscus attaches to the anterior midline of the tibial plateau or sometimes the anterior surface of the tibia just below the plateau. was saddle shaped. diminutive (1 mm) with no increased signal to suggest root attachment 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. 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. 2a, 2b, 2c). In the U.S., intraarticular injection of gadolinium-based contrast is off label. These findings are also frequently associated with genu O'Donoghue unhappy triad | Radiology Case | Radiopaedia.org Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. 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. Pseudotear Sign of the Anterior Horn of the Meniscus Radiology. Fat supressed coronal proton density-weighted (19C, D) and sagittal proton density-weighted (19E) images demonstrate postoperative changes from interval posterior horn partial meniscectomy with a thin rim of posterior horn remaining (arrow) and subchondral fractures in the medial femoral condyle and medial tibial plateau (arrowheads) with marked progression of full-thickness chondral loss in the medial compartment and extruded meniscal tissue. However, the tear changes plane of orientation over its course. A slightly overweight 44-year-old male sought evaluation for medial knee pain that persisted for months after running on the beach. The most commonly practiced Definite surfacing signal or distortion on only one image represents a possible tear. (1A) Proton density-weighted, (1B) T2-weighted, and (1C) fat-suppressed T1-weighted MR arthrographic sagittal images are provided. When interpreting MR images of the knee, it is important to assess for any change from the expected shape of the menisci. 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. Problems encountered in a discoid medial meniscus are the same as a In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). Diagnostic Image Quality of a Low-Field (0.55T) Knee MRI Protocol Using How I Diagnose Meniscal Tears on Knee MRI : American Journal of (PubMed: 17114506), BakerJC, FriedmanMV, RubinDA (2018) Imaging the postoperative knee meniscus: an evidence-based review. 7.2 Medial and Lateral Menisci Medial meniscus is larger than the lateral meniscus and is more "open" (=less C-like) and less wide. Become a Gold Supporter and see no third-party ads. Of the 54 participants, 5 had PHLM tears and 49 were normal. Anterior Horn Meniscal Tears — Fact or Fiction - Relias Media The most frequent symptom is pain that usually begins with a minor 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. typically into the anterior cruciate ligament. We use cookies to create a better experience. Kaplan EB. And, some tears do not fill with contrast during arthrography. The anterior meniscofemoral ligament (Humphrey ligament) attaches proximally on the medial femoral condyle, inferior to the PCL insertion. noted to be diminutive, with the posterior horn measuring 7 mm to 8 mm. hypoplastic meniscus was not the cause of the patients pain, suggesting At 1 year, 5 of 6 were completely asymptomatic with the remaining patient minimally painful with no suggestion of meniscal symptoms. 1427-143. MR imaging is useful for evaluation of many possible complications following meniscal surgery. Renew or update your current subscription to Applied Radiology. Considered a feature of knee osteoarthritis. Check for errors and try again. Lateral Meniscus Tear | Tyler Welch, MD be misinterpreted for more significant pathology on MRI. 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. 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. 2008; 32:212219, Magee T. Accuracy of 3-Tesla MR and MR arthrography in diagnosis of meniscal retear in the post-operative knee. structure on sagittal images on T1, proton density, and fat-saturated Sagittal T2-weighted (8B) and fat-suppressed coronal T2-weighted (8C) images reveal fluid signal (arrows) extending into the meniscal substance indicating a recurrent tear which was confirmed at second look arthroscopy. Grade 3 is a true meniscus tear and an arthroscope is close to 100 percent accurate in diagnosing this tear. 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. The Wrisberg variant may present with a Kelly BT, Green DW. published a case series of anterior horn tears of the lateral meniscus in 14 soccer players (mean age 20.2 years). meniscus is partial meniscal excision, leaving a 6- to 7-mm peripheral Illustration of the transtibial pullout repair for a tear of the posterior horn medial meniscal root (arrow). Sometimes T2 signal in a healed tear may look similar to fluid. immediatly lateral to the anterior horn of lateral meniscus and posterior to the tubercle of anteriro horn of medial meniscus . Unable to process the form. No paralabral cyst. The condition is typically asymptomatic and, therefore, is infrequently diagnosed.14 small meniscus is also seen in the wrist joint. The torn edges are aligned, and stable fixation applied with sutures or bioabsorbable implants at approximately 5 mm intervals. described in thrombocytopenia absent radius syndrome (TAR syndrome).2,3 Bilateral hypoplasia of the medial meniscus has also been reported.4. The meniscus root plays an essential role in maintaining the circumferential hoop tension and preventing meniscal displacement. The anterior and posterior sutures are shuttled down the tibial tunnel (arrowhead). Conventional MRI is useful for evaluation of posterior root morphology at the tibial tunnel fixation site, meniscal extrusion and articular cartilage. 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. 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). 2012;199(3):481-99. Diagnosis of recurrent meniscal tears: prospective evaluation of conventional MR imaging, indirect MR arthrography, and direct MR arthrography. This is a critical differentiation because the latter represents meniscal tears that can be Radial or oblique tear congurations close to or within the 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. Br Med Bull. Tears The MRI revealed a longitudinal tear in the posterior horn of the lateral meniscus. Mechanical rasping or trephination of the torn meniscus ends and parameniscal synovium is used to promote bleeding and vascular healing. Presentation - Middle-older aged individuals, non-traumatic, progressive onset of pain. this may extend to to the mid body." is this a bucket tear? Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. When it involves the posterior root, medial root tears are easier to diagnose than lateral root tears. 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. 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. To assess the prevalence of meniscal extrusion and its . Diagnostic performance is decreased following partial meniscectomy since the standard criteria used to diagnose a meniscus tear cannot be applied to the post-operative meniscus.3,4,5,6 Partial meniscectomy may distort the normal morphology of the meniscus and increased meniscal signal intensity may extend to the articular surface when a portion of the meniscus has been resected, simulating a tear. menisci develop from this mesenchymal tissue in a site where this tissue MR imaging and MR arthrography for diagnosis of recurrent tears in the postoperative meniscus. is in fact reducing the volume of the meniscus and restoring a normal A 2003 systematic review of the literature, in which 29 publications met strict inclusion criteria, demonstrated pooled weighted sensitivity and specificity of 93.3 % and 88.4 % for the medial meniscus and 79.3 % and 95.7 % for the lateral meniscus, respectively [, Most meniscal tears are visible and best seen on sagittal images. Meniscal extrusion. Medical search. Web Sagittal proton density-weighted image (8A) through the medial meniscus demonstrates signal extending to the tibial surface (arrow). That reported case was also associated with This has also been described as grade 2 signal [, Sagittal fat-suppressed T2 image of a 14-year-old patient showing a grade 2 signal in the posterior horn of the medial meniscus (PHMM). On this page: Article: Epidemiology Pathology Radiographic features History and etymology 36 year old male with history of meniscus surgery 7 years ago. 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. (Tr. A tear of the lateral meniscus can occur from a sudden injury, or from chronic wear and overload. Advantages include a less invasive method of introducing intraarticular contrast, the ability to identify areas of hyperemic synovitis or periarticular inflammation based on enhancement and administration can be performed by the technologist. The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). A tear was found and the repair was revised at second look arthroscopy. ligament and meniscal fascicles. diagnostic dilemma, as the AIMM band will be seen to extend to the On imaging alone, the radiologist may not be able to distinguish a residual tear (failed repair) from a recurrent tear in the same location. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. MRI of the knee is commonly indicated for evaluation of unresolved or recurrent knee pain following meniscal surgery. (as previously described), meniscal cyst,26 discoid lateral meniscus in the same knee (Figure 9),25 and pathologic medial patella plica.27. the example shown (Figures 1 and 2), the entire medial meniscus is ligament will help to exclude these conditions.5 In the first of the AIMM into the ACL is classified as Type 1 (inferior third), Type 2 Wrisberg variant, the morphology of the meniscus may be normal, but the Because this is a relatively new procedure, few studies have been dedicated to MRI evaluation of postoperative root repair. meniscus are not uncommon; they include an anomalous insertion of the MRI: When you tear your meniscus, a magnetic resonance imaging (MRI) scan will show the injury as white lines on black. A recurrent tear was proved at second look arthroscopy. The patient underwent an all-inside lateral meniscus repair. Of these patients treated nonoperatively, 6 had a diagnosis of an isolated anterior horn tear on MRI. of the menisci can be summarized as providing: Clark and Ogden studied the natural development of the menisci in the 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). Clin Orthop Relat Res 2013; 471: pp. These include looking for a 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. Objectives: Low-field MRI at 0.55 Tesla (T) with deep learning image reconstruction has recently become commercially available. measurements of the posterior horn of the medial meniscus may vary, but Continuous meniscal tissue bridged the anterior and posterior horns of the lateral meniscus on 3 consecutive sagittal slices (Figure 1B). 2. 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. The fat-suppressed sagittal T1-weighted post arthrogram view (7C) demonstrates gadolinium extending into the meniscal substance. Root tears are often large radial tears that extend through the entire AP width of the meniscus. However, few studies have directly compared the medial and lateral root tears. and ACL tears can be mistaken for AIMM, but carefully tracing the AJR Am J Roentgenol 2009;193:515-523. We will review the common meniscal variants, which Anterior lateral cysts extended . 1 ). Arthrofibrosis and synovitis are also relatively common. This scan showed a radial MMT. the medial meniscus. no specific MR criteria for classifying discoid medial menisci, and the There Horizontal (degenerative) tears run relatively parallel the tibial plateau. 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? The meniscus may also become hypertrophic. 2002;30(2):189-192. Objective Parameniscal cysts have a very high association with meniscal tears in all locations except the anterior horn lateral meniscus (AHLM). At the time the article was last revised Yahya Baba had How I Diagnose Meniscal Tears on Knee MRI. of the meniscus. A Study of Retrieved Allografts Used for ACL Surgery, Long-Term Results of Meniscus Allograft Transplantation with Concurrent ACL Reconstruction, Anterior Horn Meniscal Tears — Fact or Fiction, How Triathletes Can Use Cycling Cadence to Maximize Running Performance, Pharmacology Watch: HRT - Position Paper Places Benefits in Question, Clinical Briefs in Primary Care Supplement. Schwenke M, Singh M, Chow B Anterior Cruciate Ligament and Meniscal Tears: A Multi-modality Review. The post arthrogram view (13B) reveals gadolinium within the repair site. The self-reported complication rate for partial meniscectomy is 2.8% and meniscus repair is 7.6%. An intact meniscal repair was confirmed at second look arthroscopy. CT arthrography is a recommended alternative for patients who are not MR eligible. What Is a Tear of the Anterior Horn of the Lateral Meniscus? For DSR inquiries or complaints, please reach out to Wes Vaux, Data Privacy Officer, Learn more. meniscal injury. Tears of the anterior horn of the medial meniscus, an inferior patella plica, and ACL tears can be mistaken for AIMM, but carefully tracing the ligament will help to exclude these conditions. 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. Figure 7: Meniscofemoral ligament. Magnetic resonance imaging (MRI) is the most accurate imaging technique in the diagnosis of meniscal lesions and represents a standard tool in knee evaluation.