MRI appearance of Wrisberg variant of discoid lateral meniscus. congenital anomalies affect the lateral meniscus, most commonly a Resnick D, Goergen TG, Kaye JJ, et al. Discoid lateral meniscus of the knee joint: Nature, mechanism, and operative treatment. Meniscus tears are either degenerative or acute. Illustration of the transtibial pullout repair for a tear of the posterior horn medial meniscal root (arrow). Complex or deep radial tears were found in three of five cases of lateral meniscus extrusion and normal root. Most patients are asymptomatic, but injury to the meniscus can Meniscal transplant is usually reserved for patients younger than 50 years who have normal axial alignment. morphology but lacks its posterior attachments; ie, the meniscotibial Sagittal T2-weighted image (10B) reveals no fluid at the repair site. Connolly B, Babyn PS, Wright JG, Thorner PS. 2a, 2b, 2c). MRI c spine / head jxn - they can have stenosis of foramen magnum . Disadvantages include increased cost, increased patient time, potential for adverse reactions to contrast agent compared to conventional MRI and lack of joint distention. Pain is typically medial and activity-related (e.g. 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. ligament will help to exclude these conditions.5 In the first At surgery, the torn part of the meniscus was in the intercondylar notch and chewed up and not amenable to repair. 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. 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. It splits into two bands at the PCL, named Humphry(anterior to the PCL) and Wrisberg (posterior to the PCL). The discoid lateral-meniscus syndrome. With age, increased connective tissue stiffness of the meniscus develops secondary to elastin degradation and collagen rigidification.2. Posteroinferior displacement of the meniscal tissue (arrowheads) is also diagnostic of recurrent tear. Associated anomalies in a discoid medial AJR Am J Roentgenol. Type 1: A complete slab of meniscal tissue with complete tibial coverage. 2006; 187:W565568. collapse and widening of the medial joint space (Figure 7). According to one source, they are thought to account for ~10% of all arthroscopic meniscectomies 5. 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. Recent evidence suggests that decreased extrusion may correlate to better clinical outcomes.18. Arthroscopy: The Journal of Arthroscopic & Related Surgery. Discoid lateral meniscus in children. of the meniscus. 36 year old male with history of meniscus surgery 7 years ago. AJR Am J Roentgenol 2009;193:515-523. Kaplan EB. In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). Disadvantages include patient discomfort, increased cost, physician time needed for the procedure and radiation exposure during fluoroscopy. The anomalous insertion the intercondylar notch, most commonly to the mid ACL, and less commonly {"url":"/signup-modal-props.json?lang=us"}, Weerakkody Y, Baba Y, Knipe H, et al. The patient subsequently underwent successful partial medial meniscectomy. 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. typically into the anterior cruciate ligament. 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. A Wrisberg type variant has not been documented in 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. Repair devices including arrows, darts and sutures are used to approximate the torn edges of the meniscus. Considered a feature of knee osteoarthritis. Note the symmetrical shape of the lateral meniscus (left) with similar size of the anterior and posterior horns. On imaging alone, the radiologist may not be able to distinguish a residual tear (failed repair) from a recurrent tear in the same location. The patient had a recent new injury with increased pain. the menisci of the knees. Anterior lateral cysts extended . Definite surfacing signal or distortion on only one image represents a possible tear. In cases like this, MR arthrography is quite helpful. They often tend to be radial tears extending into the meniscal root. They are most frequently seen at the posterior horn of the medial meniscus. Pre-operative fat supressed coronal proton density-weighted image (19A) demonstates a posterior root radial tear (arrow). gestation, about the time when the knee joint is fully formed.1 Throughout fetal development, they found that the size of the lateral meniscus is highly variable, unlike the medial meniscus. Still, many clinicians choose to use conventional MRI for initial postoperative imaging which may show displaced meniscal fragments, new tears in different locations or internal derangement not involving the meniscus. 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. 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 Learn more. After preparing the recipient knee by creating a matching keyhole trough in the tibia, the surgeon slides the allograft bone plug into its matching tibial slot and sutures the periphery of the allograft meniscus to the capsule. Surgical Outcomes Lysholm Score As DLM is a congenital anomaly, the ultrastructural features and morphology differ from those of the normal meniscus, potentially leading to meniscal tears. The meniscal repair is intact. 1427-143. It is often explained by fibers of the anterior cruciate ligament and the covering synovium . Magnetic resonance imaging (MRI) is the most accurate imaging technique in the diagnosis of meniscal lesions and represents a standard tool in knee evaluation. MR criteria are used to make the diagnosis. Radial or oblique tear congurations close to or within the meniscus . 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. Best assessed on T2 weighted sequences. Following partial meniscectomy, the knee is at increased risk for osteoarthritis. Examination showed lateral joint line tenderness and a positive McMurray sign. The ends of the anterior and posterior horns are firmly attached to the tibia at their roots. The fat-suppressed sagittal T1-weighted post arthrogram view (7C) demonstrates gadolinium extending into the meniscal substance. 9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion. . These findings are also frequently associated with genu ligament, and the posterior horn may translate or rotate due to Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. Each meniscus has three main parts, the back (posterior horn), middle (body), and front (anterior horn). Acute partial interstitial to near complete anterior cruciate ligament tear is noted at its posterior end with femoral deep lateral sulcus sign. 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. discoid lateral meniscus is a relatively uncommon developmental variant Knee Surg Sports Traumatol Arthrosc. MR imaging is useful for evaluation of many possible complications following meniscal surgery. 800-688-2421. No meniscal tear is seen, but the root attachment was also noted to be On the fat-supressed proton density-weighted coronal (17A) and axial (17B) images, notice the trapazoidal shaped bone bridge (arrow) placed in the tibial slot with menscal allograft attached at the anterior and posterior roots. St. Louis County's newspaper of politics and culture Comparison of Postoperative Antibiotic Regimens for Complex Appendicitis: Is Two Days as Good as Five Days? In the U.S., intraarticular injection of gadolinium-based contrast is off label. In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). (as previously described), meniscal cyst,26 discoid lateral meniscus in the same knee (Figure 9),25 and pathologic medial patella plica.27. In this section, the major patterns of tears are described and depicted in MRIs and arthroscopy images. Development of the menisci of the human knee Lateral Meniscus: Anatomy The lateral meniscus is seen as a symmetric bow tie in the sagittal plane on at least one or two sections before it divides into two asymmetric triangles near the midline. mimicking an anterior horn tear. 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 He presented after a few months with symptoms of instability. Objectives: Low-field MRI at 0.55 Tesla (T) with deep learning image reconstruction has recently become commercially available. Anterior horn lateral meniscus tear A female asked: Mri: "macerated anterior horn lateral meniscus with inferiorly surfacing tear. meniscus are not uncommon; they include an anomalous insertion of the One important reason for such discrepancies is a failure to understand the transverse geniculate ligament of the knee (TGL). An abnormal shape may indicate a meniscal tear or a partial meniscectomy. Because there is less pressure on the meniscus there, it is difficult to evaluate the anterior region of the meniscus. 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. 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. Total meniscectomy is rarely performed unless the meniscus is so severely damaged that no salvageable meniscal tissue remains. Renew or update your current subscription to Applied Radiology. Sagittal proton density-weighted image (7A) through the medial meniscus demonstrates increased signal extending to the tibial surface (arrow). These features constitute O'Donoghue unhappy triad. 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 MRI revealed a longitudinal tear in the posterior horn of the lateral meniscus. frequently. Radiology. The purpose of our study was to determine if cysts of the ACL are the origin of cysts adjacent to the AHLM. the example shown (Figures 1 and 2), the entire medial meniscus is 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 . The trusted source for healthcare information and CONTINUING EDUCATION. The posterior horn is always larger than the anterior horn. published a case series of anterior horn tears of the lateral meniscus in 14 soccer players (mean age 20.2 years). In this case, we can determine that there is a new tear in a different location. There is no universally accepted system for classifying meniscal tear patterns. Discoid lateral meniscus. 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. There was no history of a specific knee injury. CT arthrography is a recommended alternative for patients who are not MR eligible. The meniscal body is firmly attached to the deep portion of the medial collateral ligament complex via the meniscotibial ligament. The Journal of bone and joint surgery American volume. How I Diagnose Meniscal Tears on Knee MRI. as at no time in development does the meniscus have a discoid Type 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 symptoms proximal medial tibia was convex and the distal medial femoral condyle 4). Kim SJ, Moon SH, Shin SJ. Radiographs may Radial Tear of the Medial Meniscal Root: Reliability and Accuracy of MRI for Diagnosis. Zonal variation is also seen in the density of meniscus cells and their phenotypes with a chondrocytic inner zone and fibroblastic outer zone. The lateral meniscus is produced by the varus tension and tibial IR. 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. A previous study by De Smet et al. 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 Controlling Blood Pressure During Pregnancy Could Lower Dementia Risk, Researchers Address HIV Treatment Gap Among Underserved Population, HHS Announces Reorganization of Office for Civil Rights, FDA Adopts Flu-Like Plan for an Annual COVID Vaccine. Tibial meniscal dynamics using three-dimensional reconstruction of magnetic resonance images. The remaining 42 cases were located in the red zone (19 cases) or the red-white zone. (Tr. The most common Congenital discoid cartilage. Anterior horn tear of the lateral meniscus in footballers with a stable knee is characterized by pain at the anterolateral aspect of the knee during knee extension, especially when kicking. 3 is least common. A detached posterior root is functionally equivalent to a total meniscectomy with loss of its ability to withstand hoop stress. The diagnosis of tears of the anterior horn of the meniscus by magnetic resonance imaging (MRI) is sometimes different from that obtained by arthroscopic examination. horns to the meniscal diameter on a sagittal slice that shows a maximum 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. For information on new subscriptions, product 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. Root tears are associated with a high risk for osteoarthritis. Increased signal intensity at the anterior horn of the lateral meniscus was seen on the images of seven of the 11 MR studies of the volunteers. On MRI, longitudinal tears appear as a vertical line of abnormal signal contacting articular surface. 2002;30(2):189-192. We use cookies to create a better experience. In the previously reported cases, as well as in this case, the posterior fascicles and meniscotibial ligament are absent and a high They often tend to be radial tears extending into the meniscal root. 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 . An intact meniscal repair was confirmed at second look arthroscopy. The congenitally absent meniscus appears to influence the development In children, sometimes an increased signal is seen within meniscus due to increased vascularity, but usually the signal does not contact articular surface. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. Thompson WO, Thaete FL, Fu FH, Dye SF. 2020;49(1):42-49. congenital absence of the cruciate ligaments. Fellowship-trained musculoskeletal radiologists read 99% of the MRIs. Results: In a consecutive series of 301 ACL reconstructions, 50 patients (33 male, 17 female) with a mean age of 29.6 years (range, 14-61 years) were diagnosed with a medial meniscal ramp lesion at . acromioclavicular, sternoclavicular, and temporomandibular joints. 2006; 88:660667, Boutin RD, Fritz RC, Marder RA. Medial meniscus posterior horn peripheral longitudinal tear treated with repair. Schwenke M, Singh M, Chow B Anterior Cruciate Ligament and Meniscal Tears: A Multi-modality Review. Longitudinal (longitudinal, peripheral-vertical) tears run parallel to the circumference of the meniscus along its longitudinal axis, separating the meniscus into central and peripheral portions (Fig. and ACL tears can be mistaken for AIMM, but carefully tracing the A 510, 210-pound 16-year-old male injured his left knee while kicking a football. A slightly overweight 44-year-old male sought evaluation for medial knee pain that persisted for months after running on the beach. ligaments are absent, most commonly the anterior cruciate ligament (ACL) That reported case was also associated with For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. MR imaging evaluation of the postoperative knee. These are like large radial tears and can destabilize a large portion of the meniscus. 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 ]. On examination, the patient had medial joint line tenderness with positive McMurray test. In this case the roots remained intact at the bone bridge, but the meniscal allograft detached from the joint capsule at the posterior and middle third with displacement into the central weightbearing surface (arrowheads) on sagittal T2-weighted (17C) and fat-suppressed axial proton density-weighted (17D) images. It is important to know the age of the patient when interpreting the MRI. Media community. The MRI also demonstrated moderate degenerative spurring at the lateral joint compartment, a large knee joint effusion with . (PubMed: 17114506), BakerJC, FriedmanMV, RubinDA (2018) Imaging the postoperative knee meniscus: an evidence-based review. high fibula head and a widened lateral joint space.20 Several AJR Am J Roentgenol. posterior horn usually measures 12 mm to 16 mm in the sagittal plane in Close clinical correlation is advised before recommending surgery based on this finding alone. In these cases, MR arthrography may provide additional diagnostic utility. On MRI, they exhibit abnormal horizontal linear signal contacting the inferior articular surface near the free edge or less commonly the superior surface. 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. Magn Reson Imaging Clin N Am 2014;22(4): 517555, White LM, Schweitzer ME, Weishaupt D, Kramer J, Davis A, Marks PH. Sagittal PD (. AJR Am J Roentgenol 211(3):519527, De Smet AA. Sagittal proton density (PD) images through normal medial (, The medial meniscus is larger, more oblong, and normally has a larger posterior horn than anterior horn in cross section. Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. 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. 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. Is sport activity possible after arthroscopic meniscal allograft transplantation? History of longitudinal medial meniscus tear managed by meniscal repair (arrows). 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. 2006;239(3):805-10. There is a medial and a lateral meniscus. Root tears are often large radial tears that extend through the entire AP width of the meniscus. 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. (1A) Proton density-weighted, (1B) T2-weighted, and (1C) fat-suppressed T1-weighted MR arthrographic sagittal images are provided. 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. Symptomatic anomalous insertion of the medial meniscus. Stein T, Mehling AP, Welsch F, von EisenhartRothe R, Jger A. While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. Grade 3 is a true meniscus tear and an arthroscope is close to 100 percent accurate in diagnosing this tear. the posterior horn is usually much larger than the anterior horn (the The shape of the meniscus is formed at the eighth week of 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. ; Lee, S.H. 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. 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. The patient failed conservative management of aspiration and cortisone injection. However, the tear changes plane of orientation over its course. If a meniscus tear shows up on a MRI, it is considered a Grade 3. Stay up to date with the latest in Practical Medical Imaging and Management with Applied Radiology. To assess the prevalence of meniscal extrusion and its . The medial meniscus covers 60% of the medial compartment. However, clinically significant tears that can mechanically impinge were unlikely to have been missed. However, recognizing these variants is important, as they can 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. of the menisci can be summarized as providing: Clark and Ogden studied the natural development of the menisci in the Also, the inferior patella plica inserts on the Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. 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 . The anterior meniscofemoral ligament (Humphrey ligament) attaches proximally on the medial femoral condyle, inferior to the PCL insertion.