variant, and discoid medial meniscus. Results: Arthroscopic examination of the anterior horn of the lateral meniscus in all 22 patients was normal. 2. MRI appearance of Wrisberg variant of discoid lateral meniscus. posterior horn of the medial meniscus include a triangular hypointense The shape of the meniscus is formed at the eighth week of 2014; 43:10571064, McCauley TR. The sagittal proton density-weighted image (2A) demonstrates increased signal intensity at the periphery of the medial meniscus posterior horn (arrow) but no fluid signal on the sagittal T2-weighted image (2B) and no gadolinium extension into this area on the MR arthrogram sagittal fat-suppressed T1-weighted arthrographic image (2C) consistent with a healed repair. (PubMed: 17114506), BakerJC, FriedmanMV, RubinDA (2018) Imaging the postoperative knee meniscus: an evidence-based review. Shepard et al conclude that with a 74% false-positive rate, anterior horn tears should be treated surgically only if clinical correlation exists. By continuing to use our site, you consent to the use of cookies outlined in our Privacy Policy. A 510, 210-pound 16-year-old male injured his left knee while kicking a football. partly divides a joint cavity, unlike articular discs, which completely acromioclavicular, sternoclavicular, and temporomandibular joints. 2002;30(2):189-192. Radiology. Acute partial interstitial to near complete anterior cruciate ligament tear is noted at its posterior end with femoral deep lateral sulcus sign. Direct MR arthrography requires intraarticular injection of 20-50 mL of dilute gadolinium contrast prior to imaging which distends the joint capsule and offers a high signal to noise ratio on T1-weighted images with contrast extension into the meniscal substance indicating a recurrent tear or an unhealed repair. 9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion. published a case series of anterior horn tears of the lateral meniscus in 14 soccer players (mean age 20.2 years). Presentation - Middle-older aged individuals, non-traumatic, progressive onset of pain. Congenital discoid cartilage. Sagittal proton density-weighted image (9A) demonstrates no high signal abnormality. Source: Shepard MF, et al. 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. menisci (Figure 8). of the Wrisberg ligament in patients with a complete lateral discoid That reported case was also associated with The patient underwent a successful partial medial meniscectomy and was encouraged to seek low-impact exercise. There are Direct and indirect MR arthrography have been shown to be superior to conventional MRI for detection of recurrent meniscal tears in greater than 25% partial meniscectomies and meniscal repairs; however, conventional MRI is commonly used for initial evaluation of the postoperative meniscus with MR arthrography reserved for equivocal cases. History of medial meniscus posterior horn and body partial meniscectomy. On examination, the patient had medial joint line tenderness with positive McMurray test. The medial meniscus is asymmetrical with a larger posterior horn. pretzels dipped in sour cream. 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. 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). The posterior root of the lateral meniscus (PRLM) attaches along the posterior aspect of the intercondylar eminence of the tibia (Fig. 1. 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. 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. 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. Wrisberg variant, the morphology of the meniscus may be normal, but the Am J Sports Med 2010; 38:15421548, LaPrade RF, Matheny LM, Moulton SG, James EW, Dean CS. Disadvantages include patient discomfort, increased cost, physician time needed for the procedure and radiation exposure during fluoroscopy. Concise, to-the-point text covers MRI for the entire musculoskeletal system, presented in a highly templated format. MRI Findings: Medial meniscus: Tear of the posterior horn seen to the inferior articular surface continuing into the posterior body and becoming more vertical. Exam showed a mild effusion and medial joint line tenderness. joint: Morphologic changes and their potential role in childhood De Smet A. It is usually seen near the lateral meniscus central attachment site. When bilateral, they are usually symmetric. Sometimes T2 signal in a healed tear may look similar to fluid. Arthroscopy: The Journal of Arthroscopic & Related Surgery. The main functions during movement, and less commonly joint-line tenderness, reduced 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. Grade II hyperintense horizontal signal of posterior horn of medial meniscus is noted. discoid lateral meniscus, including a propensity for tears to occur and 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 Become a Gold Supporter and see no third-party ads. A meniscus is a crescent-shaped fibrocartilaginous structure that No paralabral cyst. Longitudinal medial meniscus tear managed by repair (arrow). Clinical Examination in the Diagnosis of Anterior Cruciate : JAAOS Kaplan EB. 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. The example above illustrates marked degenerative changes caused by loss of meniscal function. They found that 76 (8%) of these indicated a tear of the anterior horn of either the medial or lateral meniscus. Meniscal extrusion. Medical search. Web Factors affecting meniscal extrusion: correlation with MRI, clinical Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. Anterior horn of the lateral meniscus: another potential pitfall in MR 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. Cho JM, Suh JS, Na JB, et al. that this rare condition is also clinically asymptomatic. While this test will show a tear up to 90% of the time, it does not always. no financial relationships to ineligible companies to disclose. 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. Proper preoperative sizing of the allograft is critical for surgical success and usually performed with radiographs. Symptomatic anomalous insertion of the medial meniscus. Bilateral discoid medial menisci: Case report. Which meniscus is more likely to tear? They divide the meniscus into superior and inferior halves (Fig. Magn Reson Imaging Clin N Am 2014;22(4): 517555, White LM, Schweitzer ME, Weishaupt D, Kramer J, Davis A, Marks PH. The MRI revealed a vertical flap (oblique) tear of the medial meniscus. CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. Meniscal tears are common and often associated with knee pain. Sagittal proton density-weighted image (7A) through the medial meniscus demonstrates increased signal extending to the tibial surface (arrow). Surgical Outcomes Lysholm Score Lateral meniscus posterior horn peripheral longitudinal tear managed by repair. is much greater than in a discoid lateral meniscus, and the prevalence of the transverse ligament is comparable to the general population.5. 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. 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. MR imaging is useful for evaluation of many possible complications following meniscal surgery. 3 is least common. asymptomatic, although there is a greater propensity for discoid menisci Bucket Handle Tear of Lateral Meniscus on MRI - A Case Report Discoid lateral meniscus of the knee joint: Nature, mechanism, and operative treatment. What is a Grade 3 meniscus tear? An algorithm for computing tear meniscus profile Lee, J.W. If a meniscus tear shows up on a MRI, it is considered a Grade 3. Most lateral meniscal tears are due to twisting or turning activities or falls. Pinar H, Akseki D, Karaoglan O, et al. Following partial meniscectomy, the knee is at increased risk for osteoarthritis. At 1 year, 5 of 6 were completely asymptomatic with the remaining patient minimally painful with no suggestion of meniscal symptoms. 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. The most widely used diagnostic modalities to assess the ligament injuries are arthroscopy and Magnetic Resonance Imaging (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 ]. What is a Lateral Meniscus Tear? Most patients are asymptomatic, but injury to the meniscus can The MRI showed complete ACL tear with displaced bucket handle medial meniscus tear. 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. meniscus. Posteroinferior displacement of the meniscal tissue (arrowheads) is also diagnostic of recurrent tear. OITE 7 Flashcards | Chegg.com The self-reported complication rate for partial meniscectomy is 2.8% and meniscus repair is 7.6%. 2a, 2b, 2c). The meniscus can separate from the joint capsule or tear through the allograft. However, recognizing these variants is important, as they can History of a longitudinal medial meniscus tear managed by repair and concurrent ACL reconstruction. Discoid lateral meniscus. Thompson WO, Thaete FL, Fu FH, Dye SF. It affects 4% to 5% of the patient population,6-9 with a much higher incidence, up to 13%, in the Asian patient population.10 It is the most common meniscal variant in children.11 slab-like configuration on sagittal MR images, with > 3 bowties In children, sometimes an increased signal is seen within meniscus due to increased vascularity, but usually the signal does not contact articular surface. 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). Meniscal Roots: Current Concepts Review As such, I can count on my hands the number of isolated anterior horn meniscal tears that I have seen at surgery that I felt were symptomatic over the past 5 years. Meniscal root tearsare a type of meniscal tearin the knee where the tear extends to either the anterior or posterior meniscal root attachment to the central tibial plateau. Pagnani M, Cooper D, Warren R. Extrusion of the Medial Meniscus. pivoting). Is sport activity possible after arthroscopic meniscal allograft transplantation? 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. Most horizontal tears extend to the inferior articular surface. 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. On the proton density-weighted image (12A) persistent high signal extends to the tibial and femoral surfaces (arrow). normal knee. Relevant clinical history, prior imaging and use of operative reports will significantly improve accuracy of post-operative interpretations. We use cookies to create a better experience. from AIMM. Kim SJ, Choi CH. 2006; 88:660667, Boutin RD, Fritz RC, Marder RA. Anatomic variability and increased signal change in this area are commonly mistaken for tears. You can use Radiopaedia cases in a variety of ways to help you learn and teach. An alternative way of fastening the allograft to the donor knee involves harvesting the meniscus with a small bone plug attached to each root and then securing the plugs within osseous tunnels drilled in the recipient tibia. Renew or update your current subscription to Applied Radiology. Fellowship-trained musculoskeletal radiologists read 99% of the MRIs. The MFL was not observed in five (19%) of 26 studies of an LMRT. The lateral . Lee S, Jee W, Kim J. Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. This arises from the posterior horn of the lateral meniscus and attaches to the lateral aspect of the medial femoral condyle. Kijowski et al. 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. Clark CR, Ogden JA. treatment for stable complete or incomplete types of discoid lateral 15 year old patient with prior extensive lateral partial meniscectomy was treated with lateral chondroplasty and lateral meniscal allograft transplant with continued pain and clicking 6 weeks post-operative. The congenitally absent meniscus appears to influence the development Anterior horn of the lateral meniscus: another potential - PubMed 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 Associated anomalies in a discoid medial The prevalence of a medial discoid meniscus in patients with AIMM There are 3 main types, according to the Watanabe classification:18. 2008;191(1):81-5. The insertion site The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). 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. [emailprotected]. 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. My own experience has been similar and I make it a policy not to recommend surgery based on this diagnosis alone without good clinical correlation. They are usually due to an acute injury [. tissue only persists at the edges, where differentiation into the They are most frequently seen at the posterior horn of the medial meniscus. to tear. The common insertion of the anterior cruciate ligament (ACL) and the AHLM root may provide a pathway for disease. During an arthroscopy, we have the choice of either repairing the meniscus tear or removing the torn piece. 1427-143. Skeletal radiology. Tears can be characterized by length, depth, shape, gap, displacement, stability, dysplasia (discoid) Illustration of the transtibial pullout repair for a tear of the posterior horn medial meniscal root (arrow). PDF The Menisci on MRI Pearls and Pitfalls or the Radiology Registrar Anterior horn lateral meniscus tear A female asked: Mri: "macerated anterior horn lateral meniscus with inferiorly surfacing tear. When the cruciate These features constitute O'Donoghue unhappy triad. Thirty-one of these patients underwent subsequent arthroscopic evaluation to allow clinical correlation. Am J Sports Med. 1 ). Among these 26 studies of an LMRT . Choi S, Bae S, Ji S, Chang M. The MRI Findings of Meniscal Root Tear of the Medial Meniscus: Emphasis on Coronal, Sagittal and Axial Images. In the U.S., intraarticular injection of gadolinium-based contrast is off label. 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. small meniscus is also seen in the wrist joint. 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. Anterior lateral cysts extended . Discoid medial meniscus. Development of the menisci of the human knee Connolly B, Babyn PS, Wright JG, Thorner PS. Pain is typically medial and activity-related (e.g. Long-term outcome after arthroscopic meniscal repair versus arthroscopic partial meniscectomy for traumatic meniscal tears. Congenital absence of the meniscus is extremely rare and has been documented in TAR syndrome and in isolated case reports.2,3 This patient had relief after the initial repair surgery, then had a second injury with recurrent symptoms, which is why the surgeon felt this was a recurrent tear. Repair techniques include inside-out, outside-in or all-inside approaches. 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. 22 year-old male with a history of ACL and MCL reconstruction and medial meniscus posterior root repair. Learn more. For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. 300). In this case, we can determine that there is a new tear in a different location. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. congenital anomalies affect the lateral meniscus, most commonly a Menisci are present in the knees and the 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 . AJR Am J Roentgenol 2009;193:515-523. 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 . Each meniscus has three main parts, the back (posterior horn), middle (body), and front (anterior horn). Total meniscectomy is rarely performed unless the meniscus is so severely damaged that no salvageable meniscal tissue remains.