Magnetic resonance imaging of the postoperative meniscus: resection, repair, and replacement. At least one meniscofemoral ligament is present in 7093 % Of knees this may extend to to the mid body." is this a bucket tear? The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). Medial meniscus posterior horn peripheral longitudinal tear (arrow) seen on the sagittal proton density-weighted image (15A) and managed by repair. Discoid lateral meniscus of the knee joint: Nature, mechanism, and operative treatment. 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. The lateral meniscus is one of two fibrocartilaginous menisci of the knee. Kocher MS, Klingele K, Rassman SO. Most horizontal tears extend to the inferior articular surface. The camera can visualize the meniscus and other structures within the knee. There is no telling how much this error rate will change for radiologists less experienced with MRI. asymptomatic, although there is a greater propensity for discoid menisci At the time the article was created Yuranga Weerakkody had no recorded disclosures. As a result, the accuracy rate of diagnosis by MRI is 83.3%. varus deformity (Figure 3). Monllau J, Gonzalez G, Puig L, Caceres E. Bilateral hypoplasia of the medial meniscus. This scan showed a radial MMT. Magnetic resonance imaging (MRI) and computed tomography (CT) arthrography are both well suited for evaluation of these lesions though somewhat limited by cost and access for MRI and by invasiveness for CT arthrography . 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. (as previously described), meniscal cyst,26 discoid lateral meniscus in the same knee (Figure 9),25 and pathologic medial patella plica.27. 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 . 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. 4. 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. The superior, middle and inferior geniculate arteries are the main vascular supply to the menisci. Sagittal PD (. 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. 1427-143. 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. Rao PS, Rao SK, Paul R. Clinical, radiologic, and arthroscopic assessment of discoid lateral meniscus. They were first described by M J Pagnaniet al. Both horns of the medial meniscus are triangular with sharp points. 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. proximal medial tibia was convex and the distal medial femoral condyle ligaments are absent, most commonly the anterior cruciate ligament (ACL) There are 3 main types, according to the Watanabe classification:18. Lateral meniscal variant with absence of the posterior coronary ligament. small meniscus is also seen in the wrist joint. You have reached your article limit for the month. AJR American journal of roentgenology. posterior horn of the medial meniscus include a triangular hypointense 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 800-688-2421. Lateral meniscus posterior horn peripheral longitudinal tear managed by repair. MRI plays a critical role in influencing the treatment decision and enables information that would obviate unnecessary surgery including diagnostic arthroscopy. 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. MRI showed posterior horn of the medial meniscus (PHMM) horizontal tear with early degenerative changes. 5. 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. Magn Reson Imaging Clin N Am 2014;22(4): 517555, White LM, Schweitzer ME, Weishaupt D, Kramer J, Davis A, Marks PH. 7 Therefore, it is important for the radiologist to be familiar with the appearance of a recurrent tear versus an untorn postoperative meniscus. separate the cavity. Clinical History: An 18 year-old male with a history of a posterior horn medial meniscus peripheral longitudinal tear treated with meniscal repair at age 16 presents for MR imaging. the menisci of the knees. Discoid lateral meniscus: Prevalence of peripheral rim instability. treatment for stable complete or incomplete types of discoid lateral Vertical flap (oblique, flap, parrots beak) tears are unstable tears and occur in younger patients. They are most frequently seen at the posterior horn of the medial meniscus. meniscal injury. 2. Tibial meniscal dynamics using three-dimensional reconstruction of magnetic resonance images. 2002;30(2):189-192. A meta-analysis of 44 trials. Radiographs are usually not diagnostic, but they may show a The most widely used diagnostic modalities to assess the ligament injuries are arthroscopy and Magnetic Resonance Imaging (MRI). MRI c spine / head jxn - they can have stenosis of foramen magnum . Copy. Tears in the red zone have the potential to heal and are more amenable to repair. 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 medial meniscus, discoid lateral meniscus, including the Wrisberg 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 ]. high fibula head and a widened lateral joint space.20 Several meniscal diameter. tissue only persists at the edges, where differentiation into the 6. 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). Problems encountered in a discoid medial meniscus are the same as a of these meniscal variants is the discoid lateral meniscus, and the The patient failed conservative management of aspiration and cortisone injection. Another finding is the abnormal size or shape of the meniscus, which would indicate damaged surfaces [, To provide a greater degree of accuracy, De Smet advocated the two-slice-touch rule. To call a definite tear, one should see increased signal contacting the articular surface of the menisci on at least two images (sagittal or coronal). 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. Kim SJ, Choi CH. The anterior and posterior meniscofemoral ligaments (Humphrey and Wrisberg respectively) are commonly present with one or both found in 93-100% of patients. A 23-year-old female presented with a 2-month history of catching and pain in the knee when arising from a squatting position. (Figure 1). Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. In the previously reported cases, as well as in this case, the Congenital discoid cartilage. The lateral meniscus is more circular with a shorter radius, covering 70% of the articular surface with the anterior and posterior horns approximately the same size. Interested in Group Sales? Radiology. In cases like this, MR arthrography is quite helpful. Am J Sports Med 2017; 45:884891, Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, et al. Comparison of Postoperative Antibiotic Regimens for Complex Appendicitis: Is Two Days as Good as Five Days? insertion of the medial meniscus (AIMM) has been described, and it is congenital anomalies affect the lateral meniscus, most commonly a On examination, there was marked medial joint line tenderness and a large effusion. Close clinical correlation is advised before recommending surgery based on this finding alone. mobility, and a giving-way sensation.11, 15, 16 A high percentage of cases present with an associated meniscal tear and peripheral rim instability.9,16,17 Although discoid lateral meniscus is commonly bilateral, symptoms tend to occur on one side.15 It is characterized by an excess of meniscal tissue with a slab-like configuration in the 2 most common forms (Figure 5). Grade 3 is a true meniscus tear and an arthroscope is close to 100 percent accurate in diagnosing this tear. The example above illustrates marked degenerative changes caused by loss of meniscal function. 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. The patient had a recent new injury with increased pain. The Wrisberg variant may present with a MR imaging evaluation of the postoperative knee. 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 sagittal proton density-weighted image (13A) demonstrates linear high signal extending to the femoral and tibial surfaces (arrow). 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. Media community. appearance.12 It is now believed that the knee develops from a 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. MRI Findings: Medial meniscus: Tear of the posterior horn seen to the inferior articular surface continuing into the posterior body and becoming more vertical. MR imaging is useful for evaluation of many possible complications following meniscal surgery. On the sagittal fat-suppressed T2-weighted image (7B), fluid extends into the tear. Indications for meniscal repair typically include posttraumatic peripheral (red zone) longitudinal tears located near the joint capsule, ideally in younger patients (less than 40). Damaged meniscal tissue is removed with arthroscopic instruments including scissors, baskets and mechanical shavers until a solid tissue rim is reached with the meniscal remnant contoured, preserving of as much meniscal tissue as possible. There was no evidence of meniscal extrusion or a meniscal ghost sign (Fig. Become a Gold Supporter and see no third-party ads. MRI appearance of Wrisberg variant of discoid lateral meniscus. AJR Am J Roentgenol 2009;193:515-523. MRI: When you tear your meniscus, a magnetic resonance imaging (MRI) scan will show the injury as white lines on black. 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. Similarly, the postoperative meniscus is at increased risk for a recurrent tear either at the same or different location due redistribution of forces and increased stress on the articular surface. Medial meniscus bucket handle tears can result in a double PCL sign. What is a Grade 3 meniscus tear? Meniscal root tears are a form of radial tear that involves the central attachment of the meniscus (12a). What is your diagnosis? A classification system developed by the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine [, Longitudinal-vertical tear. frequently. 3: The Wrisberg variant, where the meniscus may have a normal Because there is less pressure on the meniscus there, it is difficult to evaluate the anterior region of the meniscus. Grade II hyperintense horizontal signal of posterior horn of medial meniscus is noted. History of a longitudinal medial meniscus tear managed by repair and concurrent ACL reconstruction. 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. 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. Root tears are often large radial tears that extend through the entire AP width of the meniscus. rim circumferentially, anteriorly, and posteriorly,19 which History of medial meniscus posterior horn and body partial meniscectomy. Development of the menisci of the human knee Studies on meniscus root tears have investigated the relationship of osteoarthritis and an anterior cruciate ligament tear. High signal close to fluid intensity contacts the tibial surface on the sagittal T2-weighted image (11B) and is equivocal. the example shown (Figures 1 and 2), the entire medial meniscus is of the meniscus. Objective Parameniscal cysts have a very high association with meniscal tears in all locations except the anterior horn lateral meniscus (AHLM). Anterior lateral cysts extended . 36 year old male with history of meniscus surgery 7 years ago. 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. 2002; 222:421429, Ciliz D, Ciliz A, Elverici E, Sakman B, Yuksel E, Akbulut O. History of longitudinal medial meniscus tear managed by meniscal repair (arrows). 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. 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. The meniscus may also become hypertrophic. Lateral meniscus extrusion was present in six (23%) of 26 LMRTs and five (2.2%) of 231 patients with normal meniscus roots ( P < .001). Unable to process the form. 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. Skeletal radiology. The medial meniscus is more tightly anchored than the lateral meniscus, allowing for approximately 5mm of anterior-posterior translation. In this section, the major patterns of tears are described and depicted in MRIs and arthroscopy images. Anomalous Proper preoperative sizing of the allograft is critical for surgical success and usually performed with radiographs. was saddle shaped. Recent evidence suggests that decreased extrusion may correlate to better clinical outcomes.18. According to one source, they are thought to account for ~10% of all arthroscopic meniscectomies 5. They often tend to be radial tears extending into the meniscal root. A tear of the meniscal root means the tear is near where it attaches to the bone, usually far in the back. Total meniscectomy is rarely performed unless the meniscus is so severely damaged that no salvageable meniscal tissue remains. The MRI sign of a radial tear is a linear, vertical cleft of abnormal high signal at the free edge (Fig. RESULTS. 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. A slightly overweight 44-year-old male sought evaluation for medial knee pain that persisted for months after running on the beach. The meniscal body is firmly attached to the deep portion of the medial collateral ligament complex via the meniscotibial ligament. 2a, 2b, 2c). How I Diagnose Meniscal Tears on Knee MRI. Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. You can use Radiopaedia cases in a variety of ways to help you learn and teach. 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. 2008; 32:212219, Magee T. Accuracy of 3-Tesla MR and MR arthrography in diagnosis of meniscal retear in the post-operative knee. Sometimes T2 signal in a healed tear may look similar to fluid. menisci develop from this mesenchymal tissue in a site where this tissue 10 The example above demonstrates the importance of baseline MRI comparison when evaluating the postoperative meniscus. Is sport activity possible after arthroscopic meniscal allograft transplantation? Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation. 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). Thus, the loss of the lateral meniscus can often lead to rather rapid onset of osteoarthritis. (Tr. Thompson WO, Thaete FL, Fu FH, Dye SF. Sagittal proton density-weighted image (9A) demonstrates no high signal abnormality. 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. 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. The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. 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. To assess the prevalence of meniscal extrusion and its . Symptomatic anomalous insertion of the medial meniscus. Meniscal transplant is usually reserved for patients younger than 50 years who have normal axial alignment. Knee Surg Sports Traumatol Arthrosc 2011; 19:147157, Gwathmey F.W., Golish S.R., Diduch D.R., et al: Complications in brief: meniscus repair. These features constitute O'Donoghue unhappy triad. Root tears are associated with a high risk for osteoarthritis. 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 This is a well-done study with clinical correlation and adequate follow-up. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. may simulate a peripheral tear (Figure 6).23 The only Anatomic variability and increased signal change in this area are commonly mistaken for tears. They may not even be apparent with an arthroscopic examination. The shape of the meniscus is formed at the eighth week of Radiology. MR imaging and MR arthrography for diagnosis of recurrent tears in the postoperative meniscus. 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. 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). Longitudinal lateral meniscus tear status post repair (arrow). incomplete breakdown of the central meniscus, but this is now disputed, Shepard et al have done a nice job of telling us just how frequently this mistake can be made by fellowship trained musculoskeletal radiologists. The most common location is the anterior horn-body junction of the lateral meniscus and less commonly in the mid posterior horn or root of the medial meniscus. 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. On MRI, they exhibit abnormal horizontal linear signal contacting the inferior articular surface near the free edge or less commonly the superior surface. for the ratio of the sum of the width of the anterior and posterior 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. > 20% ratio of meniscus to tibia on the coronal image; Minimum diameter 14-15 mm on a midcoronal image; 75% Magnetic resonance imaging (MRI) of both knee joints showed an almost complete absence of the anterior and posterior horns of the medial meniscus, except for the peripheral portion, hypoplastic anterior horns and tears in the posterior horns of the lateral meniscus in both knees (Fig.