The insertion site meniscal diameter. Lateral meniscus posterior horn peripheral longitudinal tear managed by repair. the posterior horn is usually much larger than the anterior horn (the The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). An intact meniscal repair was confirmed at second look arthroscopy. With age, increased connective tissue stiffness of the meniscus develops secondary to elastin degradation and collagen rigidification.2. History of medial meniscus posterior horn and body partial meniscectomy. Radiology. Complex or deep radial tears were found in three of five cases of lateral meniscus extrusion and normal root. medial meniscus, discoid lateral meniscus, including the Wrisberg Ross JA,Tough ICK, English TA. 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. 1). 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 evaluation of the postoperative knee. However, clinically significant tears that can mechanically impinge were unlikely to have been missed. 5. What causes abnormal mobility in the medial meniscus? However, many clinicians opt to use conventional MRI as the initial postoperative imaging study and reserve MR arthrography for equivocal cases. Atypically thick and high location Meniscal tears are common and often associated with knee pain. Magnetic resonance imaging (MRI) revealed an elongated free edge of the diffusely enlarged lateral meniscus extending toward the intercondylar region on coronal T1-weighted images (Figure 1A). Become a Gold Supporter and see no third-party ads. The posterior root of the medial meniscus attaches to the tibia, just anterior and medial to the posterior cruciate ligament (PCL). 3. Tibial meniscal dynamics using three-dimensional reconstruction of magnetic resonance images. This arises from the posterior horn of the lateral meniscus and attaches to the lateral aspect of the medial femoral condyle. The remaining 42 cases were located in the red zone (19 cases) or the red-white zone. The MRI also demonstrated moderate degenerative spurring at the lateral joint compartment, a large knee joint effusion with . In this section, the major patterns of tears are described and depicted in MRIs and arthroscopy images. For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. 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. 1 ). Close clinical correlation is advised before recommending surgery based on this finding alone. History of medial meniscus posterior horn partial meniscectomy. sagittal magnetic resonance (MR) images. medial meniscus are extremely uncommon and should not be a diagnostic . Pinar H, Akseki D, Karaoglan O, et al. Development of the menisci of the human knee The self-reported complication rate for partial meniscectomy is 2.8% and meniscus repair is 7.6%. On MR arthrography, (12B), gadolinium extends through the repair site indicating a tear. 3 is least common. No paralabral cyst. A recurrent tear was proved at second look arthroscopy. The medial meniscus is more tightly anchored than the lateral meniscus, allowing for approximately 5mm of anterior-posterior translation. The most common Of the 14 athletes, 8 repairs were performed, 5 patients . 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. 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. Learn more. Additionally, the postoperative complication of new extensive synovitis is apparent on the axial view (18D). no financial relationships to ineligible companies to disclose. The sutures are tied over a cortical fixation device or Endobutton (short arrow) with the knee flexed at 90 to secure the root repair. This case features the following signs of meniscal tear: Case courtesy, Prof. Dr. Khaled Matrawy, Professor of radiology, Alexandria university, Egypt. The avulsed anterior horn of the lateral meniscus is flipped over and situated above the posterior horn. 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. Congenital absence of the meniscus is extremely rare and has been documented in TAR syndrome and in isolated case reports.2,3 On imaging alone, the radiologist may not be able to distinguish a residual tear (failed repair) from a recurrent tear in the same location. He presented after a few months with symptoms of instability. MR criteria for discoid lateral menisci are used for discoid medial The ideal technique for imaging the postoperative meniscus is a matter of active controversy and depends on the operation performed, surgeon preference and clinical question (concern for recurrent meniscal tear versus articular cartilage). The symptoms Associated anomalies in a discoid medial Type Arthroscopy: The Journal of Arthroscopic & Related Surgery. medial meniscus, and not be confined to the ACL as seen in an ACL tear. discoid lateral meniscus is a relatively uncommon developmental variant Clinical imaging. Increased intrameniscal signal is commonly seen in the transplanted allograft but does not correlate with clinical outcome. asymptomatic, although there is a greater propensity for discoid menisci MRI: When you tear your meniscus, a magnetic resonance imaging (MRI) scan will show the injury as white lines on black. According to one source, they are thought to account for ~10% of all arthroscopic meniscectomies 5. 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. ligament and meniscal fascicles. MR imaging is useful for evaluation of many possible complications following meniscal surgery. 9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion. Br Med Bull. This high rate of success, however, may not apply to anterior horn tears, which occur much less commonly than posterior horn and meniscal body tears. On sagittal proton-density and T2-weighted images, this lesion was demonstrated by sensitive but nonspecific signs, such as the flipped meniscus . They are most frequently seen at the posterior horn of the medial meniscus. (middle third), or Type 3 (superior third; intercondylar notch) (Figure 10 Lee, J.W. The most commonly practiced 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 . pivoting). MRI has high sensitivity and specificity for detecting meniscus tears in patients without prior knee surgery. Advantages include a less invasive method of introducing intraarticular contrast, the ability to identify areas of hyperemic synovitis or periarticular inflammation based on enhancement and administration can be performed by the technologist. MRI showed posterior horn of the medial meniscus (PHMM) horizontal tear with early degenerative changes. On the sagittal fat-suppressed T2-weighted image (7B), fluid extends into the tear. mesenchymal mass that differentiates into the tibia, femur, and 2020;49(1):42-49. 36 year old male with history of meniscus surgery 7 years ago. The clinical significance of anterior horn meniscal tears diagnosed on magnetic resonance images. You can use Radiopaedia cases in a variety of ways to help you learn and teach. When interpreting MR images of the knee, it is important to assess for any change from the expected shape of the menisci. The MRI sign of a radial tear is a linear, vertical cleft of abnormal high signal at the free edge (Fig. Kijowski et al. There is no telling how much this error rate will change for radiologists less experienced with MRI. Best assessed on T2 weighted sequences. Sagittal proton density-weighted image (8A) through the medial meniscus demonstrates signal extending to the tibial surface (arrow). Nakajima T, Nabeshima Y, Fujii H, et al. 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. The anterior horn of the menisci, especially the lateral meniscus, is an area commonly confused on MRI. It can be divided into five segments: anterior horn, anterior, middle and posterior segments, and posterior horn. Total meniscectomy is rarely performed unless the meniscus is so severely damaged that no salvageable meniscal tissue remains. 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. Discoid lateral meniscus and the frequency of meniscal tears. Discoid lateral meniscus. 300). The Journal of bone and joint surgery American volume. of the meniscus. The lateral . the intercondylar notch, most commonly to the mid ACL, and less commonly For information on new subscriptions, product However, recognizing these variants is important, as they can Description. Among these 26 studies of an LMRT . Magnetic resonance imaging (MRI) is the most accurate imaging technique in the diagnosis of meniscal lesions and represents a standard tool in knee evaluation. The meniscal body is firmly attached to the deep portion of the medial collateral ligament complex via the meniscotibial ligament. anterior horn of the medial meniscus into the anterior cruciate ligament 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. CT arthrography is a recommended alternative for patients who are not MR eligible. 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. 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. is in fact reducing the volume of the meniscus and restoring a normal Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. Longitudinal lateral meniscus tear status post repair (arrow). may simulate a peripheral tear (Figure 6).23 The only 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. Surgical Outcomes Lysholm Score Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. menisci (Figure 8). was saddle shaped. The patient had a recent new injury with increased pain. Shepard and colleagues at UCLA specifically analyzed this by reviewing 947 consecutive MRIs. 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 has also been described as grade 2 signal [, Sagittal fat-suppressed T2 image of a 14-year-old patient showing a grade 2 signal in the posterior horn of the medial meniscus (PHMM). AJR Am J Roentgenol 2009;193:515-523. FSE T2-weighted images, with a slab-like appearance on coronal images. posterior horn of the medial meniscus include a triangular hypointense Discoid lateral meniscus in children. Type 1 is most common, and type 2006;239(3):805-10. The most important clinical concern at the time of MRI imaging is often high-grade articular cartilage loss. meniscus are not uncommon; they include an anomalous insertion of the 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. Generally, An abnormal shape may indicate a meniscal tear or a partial meniscectomy. The prevalence of a medial discoid meniscus in patients with AIMM Following partial meniscectomy, the knee is at increased risk for osteoarthritis. Midterm results in active patients. Sagittal proton density-weighted image (9A) demonstrates no high signal abnormality. . 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 ]. frequently. The anomalous insertion 1991;7(3):297-300. Radiology. Skeletal radiology. Sagittal proton density-weighted image (6A) through the medial meniscus following partial meniscectomy and debridement of the inferior articular surface shows increased PD signal contacting the inferior articular surface (arrow) but no T2 fluid signal at the surgical site (6B) and no gadolinium signal in the meniscus (6C). Acute partial interstitial to near complete anterior cruciate ligament tear is noted at its posterior end with femoral deep lateral sulcus sign. Pain is typically medial and activity-related (e.g. It is important to know the age of the patient when interpreting the MRI. does not normally occur.13. The most widely used diagnostic modalities to assess the ligament injuries are arthroscopy and Magnetic Resonance Imaging (MRI). As DLM is a congenital anomaly, the ultrastructural features and morphology differ from those of the normal meniscus, potentially leading to meniscal tears. Again, this emphasizes the importance of accurate history, prior imaging and operative reports. A classification system developed by the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine [, Longitudinal-vertical tear. Meniscal disorders: Normal, discoid, and cysts. 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. These findings are also frequently associated with genu The posterior cruciate ligament is intact. We hope you found our articles The patient underwent partial medial meniscectomy and ACL reconstruction. CT arthrography is recommended for patients with MRI contraindications or when extensive susceptibility artifact from hardware obscures the meniscus. 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 of a case of discoid medial cartilage, with an embryological note. At the time the case was submitted for publication Mostafa El-Feky had no recorded disclosures. The Wrisberg variant may present with a during movement, and less commonly joint-line tenderness, reduced Semin Musculoskelet Radiol 2005;9(2):11624, Chung KS, Ha JK, Ra HJ, Nam GW, Kim JG. Meniscal root tear. Heron, D, Bonnard C, Moraine C,Toutain A. Agenesis of cruciate found that the absence of a line of increased signal through the meniscus extending to the articular surface on proton density and T2-weighted images was a reliable MRI finding for an untorn post-operative meniscus with 100% sensitivity. Clark CR, Ogden JA. include hypoplastic menisci, absent menisci, anomalous insertion of the Monllau J, Gonzalez G, Puig L, Caceres E. Bilateral hypoplasia of the medial meniscus. pretzels dipped in sour cream. of the distal femur and proximal tibia, and in the case report of Illustration of the transtibial pullout repair for a tear of the posterior horn medial meniscal root (arrow). By continuing to use our site, you consent to the use of cookies outlined in our Privacy Policy. The post arthrogram view (13B) reveals gadolinium within the repair site. 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. Objectives: Low-field MRI at 0.55 Tesla (T) with deep learning image reconstruction has recently become commercially available. from AIMM. Collagen fibers are arranged for transferring compressive loads into circumferential hoop stresses, secured by radially oriented tie fibers. Diagnosis - clinical presentation with exclusion of advanced knee osteoarthritis. Monllau et al in 1998 proposed adding a fourth type, Davidson D, Letts M, Glasgow R. Discoid meniscus in children: Treatment and outcome. Meniscal root tears are a type of meniscal tear in the knee where the tear extends to either the anterior or posterior meniscal root attachment to the central tibial plateau. Sagittal T2-weighted (8B) and fat-suppressed coronal T2-weighted (8C) images reveal fluid signal (arrows) extending into the meniscal substance indicating a recurrent tear which was confirmed at second look arthroscopy. Anatomic variability and increased signal change in this area are commonly mistaken for tears. Concise, to-the-point text covers MRI for the entire musculoskeletal system, presented in a highly templated format. Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. The anterior and posterior meniscofemoral ligaments (Humphrey and Wrisberg respectively) are commonly present with one or both found in 93-100% of patients.9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion.10. 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. published a case series of anterior horn tears of the lateral meniscus in 14 soccer players (mean age 20.2 years). Kaplan EB. Of the 54 participants, 5 had PHLM tears and 49 were normal. Youderian A, Chmell S, Stull MA. The reported prevalence is 0.06% to 0.3%.25 Proper preoperative sizing of the allograft is critical for surgical success and usually performed with radiographs. MRI of the knee is commonly indicated for evaluation of unresolved or recurrent knee pain following meniscal surgery. both enjoyable and insightful. 1. Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. MRI failed to detect anterior horn injury of lateral meniscus in six (16.7%) cases, all of which were longitudinal fissure in the red zone. Lateral meniscus bucket handle tears can produce the double anterior horn sign or double ACL sign. Stein T, Mehling AP, Welsch F, von EisenhartRothe R, Jger A. The sagittal proton density-weighted image (13A) demonstrates linear high signal extending to the femoral and tibial surfaces (arrow). View Mostafa El-Feky's current disclosures, see full revision history and disclosures, Flipped meniscus - anterior horn lateral meniscus, Disproportionate posterior horn sign (meniscal tear). . The shape of the meniscus is formed at the eighth week of 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. Cho JM, Suh JS, Na JB, et al. It is believed that discoid 2012;20(10):2098-103. Meniscal surgery is common and requires accurate post-operative imaging interpretation to guide the treatment approach. Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation. 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 . They are usually due to an acute injury [. 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. Seventy-four cases of bucket-handle tears (mean age, 27.2 11.3 years; 38 medial meniscus and 36 lateral meniscus; 39 concomitant anterior cruciate ligament (ACL) reconstruction) were treated with arthroscopic repair from June 2011 to August 2021. Medial meniscus posterior horn peripheral longitudinal tear (arrow) seen on the sagittal proton density-weighted image (15A) and managed by repair. Torn lateral meniscus with superomedial and posterior flipped anterior horn. The torn edges are aligned, and stable fixation applied with sutures or bioabsorbable implants at approximately 5 mm intervals. treatment for stable complete or incomplete types of discoid lateral Tolo VT. Congenital absence of the menisci and cruciate ligaments of the knee: A case report. However, the tear changes plane of orientation over its course. 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 medial meniscus. intra-articular structures at 8 weeks gestation. The patient subsequently underwent successful partial medial meniscectomy. tissue only persists at the edges, where differentiation into the immediatly lateral to the anterior horn of lateral meniscus and posterior to the tubercle of anteriro horn of medial meniscus . Unable to process the form. Zonal variation is also seen in the density of meniscus cells and their phenotypes with a chondrocytic inner zone and fibroblastic outer zone.