the medial meniscus. Partial meniscectomy is by far the most common procedure. A classification system developed by the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine [, Longitudinal-vertical tear. Discoid lateral meniscus and the frequency of meniscal tears. Vertical flap (oblique, flap, parrots beak) tears are unstable tears and occur in younger patients. Interested in Group Sales? Kim SJ, Moon SH, Shin SJ. intra-articular structures at 8 weeks gestation. Analytical, Diagnostic and Therapeutic Techniques and Equipment 13. Sagittal proton density-weighted image (10A) demonstrates increased signal extending to the articular surface consistent with granulation tissue. Disadvantages include patient discomfort, increased cost, physician time needed for the procedure and radiation exposure during fluoroscopy. 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 . 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. 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 ]. noted to be diminutive, with the posterior horn measuring 7 mm to 8 mm. The anterior horn inserts on the tibia and continues laterally to the anterior horn of the lateral meniscus via the transverse intermeniscal ligament. Examination of the knee showed a mild effusion, 1+ Lachman, positive Pivot shift, and mild tenderness to both medial and lateral joint lines. The most important clinical concern at the time of MRI imaging is often high-grade articular cartilage loss. meniscal injury. The anterior and posterior meniscofemoral ligaments (Humphrey and Wrisberg respectively) are commonly present with one or both found in 93-100% of patients. meniscus are not uncommon; they include an anomalous insertion of the Healed peripheral medial meniscus posterior horn repair and new longitudinal tear in a different location. The Wrisberg variant may present with a Complex or deep radial tears were found in three of five cases of lateral meniscus extrusion and normal root. 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. Thirty-one of these patients underwent subsequent arthroscopic evaluation to allow clinical correlation. 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). 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. high fibula head and a widened lateral joint space.20 Several A meta-analysis of 44 trials. signal fluid cleft interposed between the posterior horn and the capsule As DLM is a congenital anomaly, the ultrastructural features and morphology differ from those of the normal meniscus, potentially leading to meniscal tears. American Board of Orthopaedic Surgery Practice of the Orthopaedic Surgeon: Part-II, certification examination case mix. On imaging alone, the radiologist may not be able to distinguish a residual tear (failed repair) from a recurrent tear in the same location. slab-like configuration on sagittal MR images, with > 3 bowties 17. The posterior cruciate ligament is intact. Concise, to-the-point text covers MRI for the entire musculoskeletal system, presented in a highly templated format. . Discoid lateral meniscus in children. When evaluating a portion of the meniscus that is in a different location than the repair, criteria for evaluating a virgin meniscus may be used for that area. Complete radial tears, root tears and large partial meniscectomies result in markedly increased contact forces at the articular surface; and in this case, full-thickness chondral loss and subchondral fractures on both sides of the joint. 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. The posterior horn is always larger than the anterior horn. hypermobility. Results: Arthroscopic examination of the anterior horn of the lateral meniscus in all 22 patients was normal. 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. A displaced longitudinal tear is a "bucket handle" tear. When interpreting MR images of the knee, it is important to assess for any change from the expected shape of the menisci. Shepard et al have done a nice job of telling us just how frequently this mistake can be made by fellowship trained musculoskeletal radiologists. variant, and discoid medial meniscus. Sagittal T2-weighted image (10B) reveals no fluid at the repair site. 5. 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. 2020;49(1):42-49. hypoplastic meniscus was not the cause of the patients pain, suggesting 22 year-old male with a history of ACL and MCL reconstruction and medial meniscus posterior root repair. 7.2 Medial and Lateral Menisci Medial meniscus is larger than the lateral meniscus and is more "open" (=less C-like) and less wide. 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. Schwenke M, Singh M, Chow B Anterior Cruciate Ligament and Meniscal Tears: A Multi-modality Review. 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 800-688-2421. 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 [. You can use Radiopaedia cases in a variety of ways to help you learn and teach. A slightly overweight 44-year-old male sought evaluation for medial knee pain that persisted for months after running on the beach. A tear of the meniscal root means the tear is near where it attaches to the bone, usually far in the back. Clark CR, Ogden JA. 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. Connolly B, Babyn PS, Wright JG, Thorner PS. The anterior root of the medial meniscus attaches to the anterior midline of the tibial plateau or sometimes the anterior surface of the tibia just below the plateau. Conventional MRI is useful for evaluation of posterior root morphology at the tibial tunnel fixation site, meniscal extrusion and articular cartilage. Klingele KE, Kocher MS, Hresko MT, et al. Financial Disclosure: None of the authors or planners for this educational activity have relevant financial relationships to disclose with ineligible companies whose primary business is producing, marketing, selling, reselling, or distributing healthcare products used by or on patients. Regardless of the imaging protocol chosen for evaluation of the postoperative meniscus, optimal imaging interpretation includes: The normal MRI appearance after partial meniscectomy is volume loss and morphologic change, commonly truncation or blunting of the meniscal free edge. Menisci ensure normal function of the posterior fascicles and meniscotibial ligament are absent and a high Magnetic resonance imaging of the postoperative meniscus: resection, repair, and replacement. The reported prevalence is 0.06% to 0.3%.25 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. Monllau J, Gonzalez G, Puig L, Caceres E. Bilateral hypoplasia of the medial meniscus. of the transverse ligament is comparable to the general population.5. 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 this page: Article: Epidemiology Pathology Radiographic features History and etymology Synopsis: In a consecutive series of nearly 1000 knee MRIs, there was a 74% false-positive rate for the diagnosis of anterior horn meniscal tears. Stein T, Mehling AP, Welsch F, von EisenhartRothe R, Jger A. problem in practice. The meniscus root plays an essential role in maintaining the circumferential hoop tension and preventing meniscal displacement. 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. Arthroscopy is considered gold standard in the diagnosis of knee ligament injuries, with diagnostic accuracy up to 94% [1], [2]; and can be used therapeutically as well. Resnick D, Goergen TG, Kaye JJ, et al. The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). Arthroscopy evaluation found a lateral meniscus peripheral (red-white zone) longitudinal tear. Findings indicate an intact meniscus following partial meniscectomy with normal intrameniscal signal. High signal close to fluid intensity contacts the tibial surface on the sagittal T2-weighted image (11B) and is equivocal. For DSR inquiries or complaints, please reach out to Wes Vaux, Data Privacy Officer, Discoid lateral meniscus was originally believed to result from an Knee Surg Sports Traumatol Arthrosc. MRI Findings: Medial meniscus: Tear of the posterior horn seen to the inferior articular surface continuing into the posterior body and becoming more vertical. 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. When bilateral, they are usually symmetric. In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). meniscus is partial meniscal excision, leaving a 6- to 7-mm peripheral Dr. Diduch, Associate Professor, Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA, is Editor of Sports Medicine Reports. Root tears are associated with a high risk for osteoarthritis. We will review the common meniscal variants, which 6. 1 ). Bilateral hypoplasia of the medial meniscus has also been Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. Lee S, Jee W, Kim J. Best assessed on T2 weighted sequences. A 64-year-old female with no specific injury presented with knee pain, swelling, and locking that she first noticed after working out at the gym. Monllau et al in 1998 proposed adding a fourth type, Surgery is useful if they are unstable and flipping in and out of the joint causing pain. When the cruciate Comparison of Postoperative Antibiotic Regimens for Complex Appendicitis: Is Two Days as Good as Five Days? Kaplan EB. Suprapatellar plica noticed, with no related cartilaginous erosions. 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. (Tr. posterior horn usually measures 12 mm to 16 mm in the sagittal plane in 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 . ADVERTISEMENT: Supporters see fewer/no ads. Considered a feature of knee osteoarthritis. Clinical imaging. 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. Note the symmetrical shape of the lateral meniscus (left) with similar size of the anterior and posterior horns. Posteroinferior displacement of the meniscal tissue (arrowheads) is also diagnostic of recurrent tear. At 1 year, 5 of 6 were completely asymptomatic with the remaining patient minimally painful with no suggestion of meniscal symptoms. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. posterior horn of the medial meniscus include a triangular hypointense Of these patients treated nonoperatively, 6 had a diagnosis of an isolated anterior horn tear on MRI. 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. 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. Shepard et al conclude that with a 74% false-positive rate, anterior horn tears should be treated surgically only if clinical correlation exists. 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. Kelly BT, Green DW. A variants of the meniscus are relatively uncommon and are frequently The condition is typically asymptomatic and, therefore, is infrequently diagnosed.14 the intercondylar notch, most commonly to the mid ACL, and less commonly ligament, and the posterior horn may translate or rotate due to The shape of the meniscus is formed at the eighth week of Type 2: An incomplete slab of meniscal tissue with 80% coverage of the lateral tibial plateau. Meniscal root tear. 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. 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). Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation. Normal menisci. 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 Sagittal T2-weighted (18B) and fat-suppressed sagittal proton density-weighted sagittal (18C) images demonstrate fluid-like signal in the posterior horn suggestive of a recurrent tear. Heron, D, Bonnard C, Moraine C,Toutain A. Agenesis of cruciate Otherwise, the increased vascularity in children has sometimes led to false-positive reading of a meniscus tear. Cho JM, Suh JS, Na JB, et al. during movement, and less commonly joint-line tenderness, reduced MRI plays a critical role in influencing the treatment decision and enables information that would obviate unnecessary surgery including diagnostic arthroscopy. The camera can visualize the meniscus and other structures within the knee. The self-reported complication rate for partial meniscectomy is 2.8% and meniscus repair is 7.6%. 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. What is your diagnosis? occur with minor trauma. Kocher MS, Klingele K, Rassman SO. Ross JA,Tough ICK, English TA. The tear was treated by partial meniscectomy at second surgery. 2014; 43:10571064, McCauley TR. The main functions Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. The symptoms Midterm results in active patients. Of the 14 athletes, 8 repairs were performed, 5 patients . Tibial meniscal dynamics using three-dimensional reconstruction of magnetic resonance images. As a result, the accuracy rate of diagnosis by MRI is 83.3%. acromioclavicular, sternoclavicular, and temporomandibular joints.