Following meniscal allograft transplantation (Figure 17), complications occur in up to 21% of procedures, including allograft failure and progressive cartilage loss.19 Repeat operations occur in up to 35% of patients, 12% requiring conversion to total knee arthroplasty. When bilateral, they are usually symmetric. Kijowski et al. If missing on MR images, a posterior root tear is present. Atypically thick and high location Sagittal proton density-weighted image (7A) through the medial meniscus demonstrates increased signal extending to the tibial surface (arrow). This is a critical differentiation because the latter represents meniscal tears that can be It is believed that discoid Each meniscus attaches to the tibia bone in the back and front via the "meniscal roots." The primary role of the meniscus is to serve as a shock-absorber and protect the underlying articular cartilage and bone. Meniscus repair is superior to partial meniscectomy in preventing osteoarthritis and facilitating return to athletic activity.11 However, the period of postoperative immobilization and activity restriction associated with meniscus repair is longer than that associated with partial meniscectomy and requires a compliant, motivated patient to be successful. This case is almost identical to the previous case with a different clinical history. 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. 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. [emailprotected]. Complete radial tears, root tears and large partial meniscectomies result in markedly increased contact forces at the articular surface; and in this case, full-thickness chondral loss and subchondral fractures on both sides of the joint. 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. MRI has high sensitivity and specificity for detecting meniscus tears in patients without prior knee surgery. Pagnani M, Cooper D, Warren R. Extrusion of the Medial Meniscus. joint: Morphologic changes and their potential role in childhood Schwenke M, Singh M, Chow B Anterior Cruciate Ligament and Meniscal Tears: A Multi-modality Review. Check for errors and try again. MRI appearance of Wrisberg variant of discoid lateral meniscus. Am J Sports Med 2010; 38:15421548, LaPrade RF, Matheny LM, Moulton SG, James EW, Dean CS. This is because most tears occur in the posterior horns [, Whether a torn meniscus is reparable depends on the type or pattern of tear, its location, and the quality of the meniscal tissue. morphology. ligaments are absent, most commonly the anterior cruciate ligament (ACL) The sensitivity of mri in detecting meniscal tears is generally good, ranging from 70-98%, with specificity in the same range in many studies. of the Wrisberg ligament in patients with a complete lateral discoid Variations in meniscofemoral ligaments at anatomical study and MR imaging. On examination, there was marked medial joint line tenderness and a large effusion. Grade 3 is a true meniscus tear and an arthroscope is close to 100 percent accurate in diagnosing this tear. Additionally, the postoperative complication of new extensive synovitis is apparent on the axial view (18D). The trusted source for healthcare information and CONTINUING EDUCATION. The sagittal proton density-weighted image (13A) demonstrates linear high signal extending to the femoral and tibial surfaces (arrow). Radiology. 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. 10 Discoid lateral meniscus. the medial meniscus. For information on new subscriptions, product diminutive (1 mm) with no increased signal to suggest root attachment 6. Normal Indications for meniscal repair typically include posttraumatic peripheral (red zone) longitudinal tears located near the joint capsule, ideally in younger patients (less than 40). 300). Arthroscopy revealed a horizontal tear of PHMM, and a partial medial meniscectomy was performed. Bilateral discoid medial menisci: Case report. Is sport activity possible after arthroscopic meniscal allograft transplantation? These features constitute O'Donoghue unhappy triad. Radial or oblique tear congurations close to or within the meniscus . Discoid lateral meniscus was originally believed to result from an 2008; 32:212219, Magee T. Accuracy of 3-Tesla MR and MR arthrography in diagnosis of meniscal retear in the post-operative knee. Sagittal proton density-weighted image (8A) through the medial meniscus demonstrates signal extending to the tibial surface (arrow). Volunteerism and Sports Medicine: Where do We Stand? small meniscus is also seen in the wrist joint. ligaments and menisci causing severe knee dysplasia in TAR syndrome. 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 The patient underwent an all-inside lateral meniscus repair. 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. Repair techniques include side-to-side repair, stabilization with suture anchors, and the transtibial pull-out technique (figure 4).12. History of medial meniscus posterior horn partial meniscectomy. Lateral meniscus extrusion was present in six (23%) of 26 LMRTs and five (2.2%) of 231 patients with normal meniscus roots ( P < .001). CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. occur with minor trauma. The anterior horn inserts on the tibia and continues laterally to the anterior horn of the lateral meniscus via the transverse intermeniscal ligament. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. On the sagittal fat-suppressed T2-weighted image (7B), fluid extends into the tear. ligament will help to exclude these conditions.5 In the first 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? Shepard et al conclude that with a 74% false-positive rate, anterior horn tears should be treated surgically only if clinical correlation exists. mesenchymal mass that differentiates into the tibia, femur, and It can be divided into five segments: anterior horn, anterior, middle and posterior segments, and posterior horn. diagnostic dilemma, as the AIMM band will be seen to extend to the 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. horns to the meniscal diameter on a sagittal slice that shows a maximum Anterior horn of the lateral meniscus: another potential pitfall in MR imaging of the knee. rim circumferentially, anteriorly, and posteriorly,19 which At the time the case was submitted for publication Mostafa El-Feky had no recorded disclosures. Repair of posterior root tears are being performed with increased frequency over the past several years. There is a medial and a lateral meniscus. On MRI, they resemble radial tears, with a linear cleft of abnormal signal seen at the free edge. 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. Materials and methods . acromioclavicular, sternoclavicular, and temporomandibular joints. 7.2 Medial and Lateral Menisci Medial meniscus is larger than the lateral meniscus and is more "open" (=less C-like) and less wide. Shepard and colleagues at UCLA specifically analyzed this by reviewing 947 consecutive MRIs. In this case, having the prior MRI exam is useful for showing the location of the initial tear and the new tear in a different location. discoid meniscus, although discoid medial menisci can occur much less Kocher MS, Klingele K, Rassman SO. On MRI, longitudinal tears appear as a vertical line of abnormal signal contacting articular surface. with mechanical features of clicking and locking. 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 . Total meniscectomy is rarely performed unless the meniscus is so severely damaged that no salvageable meniscal tissue remains. 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. The meniscus can separate from the joint capsule or tear through the allograft. The ends of the anterior and posterior horns are firmly attached to the tibia at their roots. (Tr. Radiographs may Tachibana Y, Yamazaki Y, Ninomiya S. Discoid medial meniscus. The congenitally absent meniscus appears to influence the development By continuing to use our site, you consent to the use of cookies outlined in our Privacy Policy. the rare ring-shaped meniscus, to the classification. 6 months post-operative she had increased pain prompting follow-up MRI. Most lateral meniscal tears are due to twisting or turning activities or falls. Magnetic resonance imaging of the postoperative meniscus: resection, repair, and replacement. trials, alternative billing arrangements or group and site discounts please call Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. On MR arthrography, (12B), gadolinium extends through the repair site indicating a tear. Normal 22 year-old male with a history of ACL and MCL reconstruction and medial meniscus posterior root repair. AJR Am J Roentgenol. MR criteria for discoid lateral menisci are used for discoid medial ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. no specific MR criteria for classifying discoid medial menisci, and the high fibula head and a widened lateral joint space.20 Several According to one source, they are thought to account for ~10% of all arthroscopic meniscectomies 5. The purpose of our study was to determine if cysts of the ACL are the origin of cysts adjacent to the AHLM. A previous study by De Smet et al. 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). Exam showed a mild effusion and medial joint line tenderness. A preliminary report, Principles and decision making in meniscal surgery, The Anterior Meniscofemoral Ligament of the Medial Meniscus, Accurate patient history including site and duration of symptoms, Garrett WE Jr, Swiontkowski MF, Weinstein JN, et al. They may not even be apparent with an arthroscopic examination. an adult), and approximately twice the size of the anterior horn on 2a, 2b, 2c). 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. 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. as at no time in development does the meniscus have a discoid trauma; however, other symptoms include clicking, snapping, and locking 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. The torn edges are aligned, and stable fixation applied with sutures or bioabsorbable implants at approximately 5 mm intervals. The patient failed conservative management of aspiration and cortisone injection. No meniscal tear is seen, but the root attachment was also noted to be Generally, 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 Renew or update your current subscription to Applied Radiology. 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. The aim of this study was to evaluate diagnostic values involved in conventional magnetic resonance imaging (MRI) features of MM posterior root tears (MMPRTs) and find other MRI-based findings in patients with partial MMPRTs. of the distal femur and proximal tibia, and in the case report of instance, tears of the lateral aspect of the anterior horn of the The remaining 42 cases were located in the red zone (19 cases) or the red-white zone. meniscus is partial meniscal excision, leaving a 6- to 7-mm peripheral The patient underwent a successful partial medial meniscectomy and was encouraged to seek low-impact exercise. Sagittal proton density-weighted image (10A) demonstrates increased signal extending to the articular surface consistent with granulation tissue. Root tears are often large radial tears that extend through the entire AP width of the meniscus. 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. What causes abnormal mobility in the medial meniscus? 2005; 234:5361. 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. Type 2: An incomplete slab of meniscal tissue with 80% coverage of the lateral tibial plateau. to the base of the ACL or the intercondylar notch. Note the symmetrical shape of the lateral meniscus (left) with similar size of the anterior and posterior horns. hypermobility. Tolo VT. Congenital absence of the menisci and cruciate ligaments of the knee: A case report. Repair devices including arrows, darts and sutures are used to approximate the torn edges of the meniscus. A detached posterior root is functionally equivalent to a total meniscectomy with loss of its ability to withstand hoop stress. and ACL tears can be mistaken for AIMM, but carefully tracing the Diagnosis of meniscal tears on MRI improves when these guidelines are followed to optimize signal-to-noise ratio: high-field-strength magnets are preferable (1.5 T and stronger); a high-resolution surface coil should be used; the field of view should only encompass the necessary structures and routinely be 16 cm or less; image slices should not be too thick (34 mm); and the matrix size should be at least 256192 or higher [, A normal meniscus is low signal on all sequences. They are most frequently seen at the posterior horn of the medial meniscus. While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation. hypoplastic meniscus was not the cause of the patients pain, suggesting Forty-five of the remaining patients did not undergo surgery but did undergo clinical follow-up and interview at a minimum of 1 year after the MRI to determine if they had any residual symptoms or if they received further medical treatment. during movement, and less commonly joint-line tenderness, reduced 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. In some patients, hyperintense signal may persist at the repair site on conventional MRI for several years and is thought to represent granulation tissue. On the sagittal proton density-weighted image (11A), signal contacts the tibial surface. 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. Figure 7: Meniscofemoral ligament. Unable to process the form. De Smet A. Discoid lateral meniscus of the knee joint: Nature, mechanism, and operative treatment. Type 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. For DSR inquiries or complaints, please reach out to Wes Vaux, Data Privacy Officer, Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. We use cookies to create a better experience. 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. 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. Case study, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-75066. During an arthroscopy, we have the choice of either repairing the meniscus tear or removing the torn piece. Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. Root tears are associated with a high risk for osteoarthritis. of these meniscal variants is the discoid lateral meniscus, and the meniscus are not uncommon; they include an anomalous insertion of the of the meniscus. He presented after a few months with symptoms of instability. of the anterior horn of the medial meniscus, an inferior patella plica, Interested in Group Sales? Normal shape and signal of the horns of the medial meniscus, with no evidence of tears or degenerations seen. Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. Kim EY, Choi SH, Ahn JH, Kwon JW. typically into the anterior cruciate ligament. pretzels dipped in sour cream. Tears RESULTS. Discoid lateral meniscus (DLM) is a common anatomic variant in the knee typically presented in young populations, with a greater incidence in the Asian population than in other populations. ligament, and the posterior horn may translate or rotate due to Among these 26 studies of an LMRT . They often tend to be radial tears extending into the meniscal root. Magn Reson Imaging Clin N Am 2014;22(4): 517555, White LM, Schweitzer ME, Weishaupt D, Kramer J, Davis A, Marks PH. Collagen fibers are arranged for transferring compressive loads into circumferential hoop stresses, secured by radially oriented tie fibers. Kim SJ, Choi CH. In the U.S., intraarticular injection of gadolinium-based contrast is off label. MR imaging evaluation of the postoperative knee. Arthroscopy evaluation found a lateral meniscus peripheral (red-white zone) longitudinal tear. Anterior lateral cysts extended . A 22-years old male presented with injury to right knee in a road traffic accident MRI images shows double posterior horn of lateral meniscus and absent anterior horn in coronal (A: PD; B: STIR; C . At least one meniscofemoral ligament is present in 7093 % Of knees An MRI of plaintiff's left knee conducted in May 2018 demonstrated a complex 7 tear of the posterior horn of the lateral meniscus and a suspected horizontal tear of the anterior horn of the lateral meniscus. 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. ; Lee, S.H. meniscal injury. Indirect MR arthrography is less commonly used and relies on excretion of intravascular gadolinium into the joint through synovial cells after intravenous administration of gadolinium contrast 20-90 minutes prior to the MRI exam. If a meniscus tear shows up on a MRI, it is considered a Grade 3. Ross JA,Tough ICK, English TA. congenital anomalies affect the lateral meniscus, most commonly a Discoid lateral meniscus: Prevalence of peripheral rim instability. Of the 54 participants, 5 had PHLM tears and 49 were normal. Both the healed peripheral tear and the new central tear were proved at second look arthroscopy. A tear of the ACL should also, in practice, not be a Close clinical correlation is advised before recommending surgery based on this finding alone.
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