anterior horn lateral meniscus tear: mri

2020;49(1):42-49. 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 ]. reported.4. On imaging alone, the radiologist may not be able to distinguish a residual tear (failed repair) from a recurrent tear in the same location. 2006; 187:W565568. The main functions Am J Sports Med. (PubMed: 17114506), BakerJC, FriedmanMV, RubinDA (2018) Imaging the postoperative knee meniscus: an evidence-based review. in 19916. Kijowski et al. for the ratio of the sum of the width of the anterior and posterior of the Wrisberg ligament in patients with a complete lateral discoid This emphasizes the importance of meniscal repair over meniscectomy when possible and the need for meniscal preservation when a partial meniscectomy is necessary. Check for errors and try again. With age, increased connective tissue stiffness of the meniscus develops secondary to elastin degradation and collagen rigidification.2. Bilateral complete discoid medial menisci combined with anomalous insertion and cyst formation. In these cases, MR arthrography may provide additional diagnostic utility. 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. Longitudinal lateral meniscus tear status post repair (arrow). Am J Sports Med 2010; 38:15421548, LaPrade RF, Matheny LM, Moulton SG, James EW, Dean CS. Close clinical correlation is advised before recommending surgery based on this finding alone. Discoid lateral meniscus of the knee joint: Nature, mechanism, and operative treatment. We will review the common meniscal variants, which Thirty-one of these patients underwent subsequent arthroscopic evaluation to allow clinical correlation. 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. 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. congenital absence of the cruciate ligaments. Thus, the loss of the lateral meniscus can often lead to rather rapid onset of osteoarthritis. Knee Surg Sports Traumatol Arthrosc. 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. 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 . A classification system developed by the International Society of Arthroscopy, Knee Surgery, and Orthopedic Sports Medicine [, Longitudinal-vertical tear. Associated anomalies in a discoid medial These are like large radial tears and can destabilize a large portion of the meniscus. 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. On the sagittal proton density-weighted image (11A), signal contacts the tibial surface. The camera can visualize the meniscus and other structures within the knee. 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. Papalia R, Vasta S, Franceschi F, D'Adamio S, Maffulli N, Denaro V. Meniscal Root Tears: From Basic Science to Ultimate Surgery. Description. The anterior root of the lateral meniscus attaches to the tibia, just lateral to the midline and posterior to fibers of the anterior cruciate ligament (ACL). Become a Gold Supporter and see no third-party ads. Monllau J, Gonzalez G, Puig L, Caceres E. Bilateral hypoplasia of the medial meniscus. Copy. 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 They found that 76 (8%) of these indicated a tear of the anterior horn of either the medial or lateral meniscus. Midterm results in active patients. 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 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. occur with minor trauma. A 510, 210-pound 16-year-old male injured his left knee while kicking a football. High signal close to fluid intensity contacts the tibial surface on the sagittal T2-weighted image (11B) and is equivocal. Examination of the knee showed a mild effusion, 1+ Lachman, positive Pivot shift, and mild tenderness to both medial and lateral joint lines. rim circumferentially, anteriorly, and posteriorly,19 which posterior horn usually measures 12 mm to 16 mm in the sagittal plane in 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. 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. Development of the menisci of the human knee {"url":"/signup-modal-props.json?lang=us"}, El-Feky M, Flipped meniscus - anterior horn lateral meniscus. an adult), and approximately twice the size of the anterior horn on Rao PS, Rao SK, Paul R. Clinical, radiologic, and arthroscopic assessment of discoid lateral meniscus. The patient had a recent new injury with increased pain. Pre-operative fat supressed coronal proton density-weighted image (19A) demonstates a posterior root radial tear (arrow). Type MRI has high sensitivity and specificity for detecting meniscus tears in patients without prior knee surgery. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. Anterior horn of the lateral meniscus: another potential pitfall in MR imaging of the knee. A displaced longitudinal tear is a "bucket handle" tear. Case 9: posterior root of medial meniscus, View Yuranga Weerakkody's current disclosures, see full revision history and disclosures, anterior cruciate ligament avulsion fracture, posterior cruciate ligament avulsion fracture, Ahlback classification system in assessing osteoarthritis of the knee joint, Kellgren and Lawrence system for classification of osteoarthritis, anterior cruciate ligament mucoid degeneration, MRI grading system for meniscal signal intensity, shortening or absence of the root on sagittal images, vertical fluid cleft on coronal fluid-sensitive (T2) images. Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. 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. 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. The reported prevalence is 0.06% to 0.3%.25 Weight-bearing knee X-rays showed a 50 % narrowing in the medial compartment. Br Med Bull. The most frequent symptom is pain that usually begins with a minor They were first described by M J Pagnaniet al. slab-like configuration on sagittal MR images, with > 3 bowties Radiology. intra-articular structures at 8 weeks gestation. Knee Surg Sports Traumatol Arthrosc 2011; 19:147157, Gwathmey F.W., Golish S.R., Diduch D.R., et al: Complications in brief: meniscus repair. mesenchymal mass that differentiates into the tibia, femur, and However, the use of MRI arthrography should be considered for post-operative menisci with equivocal findings on conventional MRI as the presence of high gadolinium-like signal within the meniscus would allow for a definitive diagnosis of re-tear. trials, alternative billing arrangements or group and site discounts please call While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. hypermobility. the posterior horn is usually much larger than the anterior horn (the Note that signal does not contact articular surface, The most common criterion for diagnosing meniscus tear on MRI is an increased signal extending in a line or band to the articular surface. Healed peripheral medial meniscus posterior horn repair and new longitudinal tear in a different location. 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. . the medial meniscus. Tears On examination, there was marked medial joint line tenderness and a large effusion. The posterior cruciate ligament is intact. Following partial meniscectomy, the knee is at increased risk for osteoarthritis. This is a critical differentiation because the latter represents meniscal tears that can be MRI: When you tear your meniscus, a magnetic resonance imaging (MRI) scan will show the injury as white lines on black. Repair of posterior root tears are being performed with increased frequency over the past several years. 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. Schwenke M, Singh M, Chow B Anterior Cruciate Ligament and Meniscal Tears: A Multi-modality Review. Sagittal proton density-weighted (14A) and coronal T1-weighted (14B) images reveal a recurrent bucket-handle tear through the original repair site with typical findings of a displaced meniscal flap (arrow) into the intercondylar notch. 300). The meniscus can separate from the joint capsule or tear through the allograft. There is a medial and a lateral meniscus. A recurrent tear was proved at second look arthroscopy. Meniscal transplant is usually reserved for patients younger than 50 years who have normal axial alignment. no specific MR criteria for classifying discoid medial menisci, and the 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. You have reached your article limit for the month. 2005; 234:5361. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. to tear. insertion of the medial meniscus (AIMM) has been described, and it is The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. Volunteerism and Sports Medicine: Where do We Stand? Type 2: An incomplete slab of meniscal tissue with 80% coverage of the lateral tibial plateau. ligament will help to exclude these conditions.5 In the first They may not even be apparent with an arthroscopic examination. 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. A 23-year-old female presented with a 2-month history of catching and pain in the knee when arising from a squatting position. Each meniscus has three main parts, the back (posterior horn), middle (body), and front (anterior horn). Conventional MRI imaging of the postop meniscus offers a noninvasive evaluation of the knee, but postoperative changes can mimic a recurrent or residual meniscus tear. menisci occurs. On MR arthrography, (12B), gadolinium extends through the repair site indicating a tear. The incidence was calculated based on arthroscopic findings, and the potential secondary signs of meniscal ramp tears were evaluated on MRI. It is important to know the age of the patient when interpreting the MRI. In children, sometimes an increased signal is seen within meniscus due to increased vascularity, but usually the signal does not contact articular surface. 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. 36 year old male with history of meniscus surgery 7 years ago. attachment of the posterior horn is the Wrisberg meniscofemoral What is your diagnosis? Collagen fibers are arranged for transferring compressive loads into circumferential hoop stresses, secured by radially oriented tie fibers. CT arthrography may be used to evaluate the postoperative meniscus when MRI is contraindicated. Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. The medial meniscus is more tightly anchored than the lateral meniscus, allowing for approximately 5mm of anterior-posterior translation. 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). Results: Arthroscopic examination of the anterior horn of the lateral meniscus in all 22 patients was normal. Special thanks to David Rubin, MD for providing several cases used in this web clinic. Case study, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-75066. An intact meniscal repair was confirmed at second look arthroscopy. A meta-analysis of 44 trials. At 1 year, 5 of 6 were completely asymptomatic with the remaining patient minimally painful with no suggestion of meniscal symptoms. For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. menisci develop from this mesenchymal tissue in a site where this tissue 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. Resnick D, Goergen TG, Kaye JJ, et al. Continuous meniscal tissue bridged the anterior and posterior horns of the lateral meniscus on 3 consecutive sagittal slices (Figure 1B). CT arthrography is a recommended alternative for patients who are not MR eligible. posterior fascicles and meniscotibial ligament are absent and a high Conventional MRI imaging correlates well with arthroscopic evaluation of the transplants for tears of the posterior and middle thirds of the meniscus allograft with a high sensitivity, specificity and accuracy, but results were poor for evaluation of the anterior third with a low specificity and accuracy.16 Allograft shrinkage and meniscus extrusion are common findings on postoperative MRI but do not always correlate with patient pain and function. As DLM is a congenital anomaly, the ultrastructural features and morphology differ from those of the normal meniscus, potentially leading to meniscal tears. The superior, middle and inferior geniculate arteries are the main vascular supply to the menisci. of the meniscus. Following meniscal allograft transplantation (Figure 17), complications occur in up to 21% of procedures, including allograft failure and progressive cartilage loss.19 Repeat operations occur in up to 35% of patients, 12% requiring conversion to total knee arthroplasty. MR imaging evaluation of the postoperative knee. Lateral meniscus bucket handle tears can produce the double anterior horn sign or double ACL sign. You can use Radiopaedia cases in a variety of ways to help you learn and teach. Illustration of the medial and lateral menisci. 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 ]. the rare ring-shaped meniscus, to the classification. The articular cartilage is well seen on the pre-operative sagittal proton density-weighted image (19B). 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. 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 . 2012;199(3):481-99. Grades 1 and 2 are not considered serious. 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. The purpose of our study was to determine if cysts of the ACL are the origin of cysts adjacent to the AHLM. Because this is a relatively new procedure, few studies have been dedicated to MRI evaluation of postoperative root repair. Variations in meniscofemoral ligaments at anatomical study and MR imaging. AJR Am J Roentgenol 211(3):519527, De Smet AA. Bilateral discoid medial menisci: Case report. Pain is typically medial and activity-related (e.g. Lateral meniscus tears of the posterior root are a common concomitant injury to anterior cruciate ligament (ACL) tears [6, 16, 20]. 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 [. Disadvantages include increased cost, increased patient time, potential for adverse reactions to contrast agent compared to conventional MRI and lack of joint distention. The MFL was not observed in five (19%) of 26 studies of an LMRT. bilaterally absent menisci reported by Tolo et al,3 the Meniscal disorders: Normal, discoid, and cysts. are reported cases of complete absence of the medial meniscus as 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. 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. They often tend to be radial tears extending into the meniscal root. collapse and widening of the medial joint space (Figure 7). Arthroscopy for Medial Meniscus Tears The decision to repair or remove the torn portion is made at the time of surgery. In the previously reported cases, as well as in this case, the If a meniscus tear shows up on a MRI, it is considered a Grade 3. They maintain a relatively constant distance from the periphery of the meniscus [. 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. 2006; 88:660667, Boutin RD, Fritz RC, Marder RA. 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). A Wrisberg type variant has not been documented in Nakajima T, Nabeshima Y, Fujii H, et al. Sagittal proton density-weighted image (7A) through the medial meniscus demonstrates increased signal extending to the tibial surface (arrow). 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. proximal medial tibia was convex and the distal medial femoral condyle 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. What are the findings? noted to be diminutive, with the posterior horn measuring 7 mm to 8 mm. And, some tears do not fill with contrast during arthrography. Because there is less pressure on the meniscus there, it is difficult to evaluate the anterior region of the meniscus. 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). is much greater than in a discoid lateral meniscus, and the prevalence Magnetic resonance imaging (MRI) is the most accurate imaging technique in the diagnosis of meniscal lesions and represents a standard tool in knee evaluation. during movement, and less commonly joint-line tenderness, reduced Root tears are associated with a high risk for osteoarthritis. It is possible that there could have been some tears missed at arthroscopy that were on the undersurface of the anterior horn, an area which is extremely difficultif not impossibleto visualize. When bilateral, they are usually symmetric. Zonal variation is also seen in the density of meniscus cells and their phenotypes with a chondrocytic inner zone and fibroblastic outer zone. Exam showed a mild effusion and medial joint line tenderness. There 2002; 222:421429, Ciliz D, Ciliz A, Elverici E, Sakman B, Yuksel E, Akbulut O. least common is complete congenital absence of the menisci. De Smet A. There is no universally accepted system for classifying meniscal tear patterns. This article focuses on When it involves the posterior root, medial root tears are easier to diagnose than lateral root tears. 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. Type 1: A complete slab of meniscal tissue with complete tibial coverage. Of these 45 patients, there was an average of 3.74 additional pathological conditions noted on the MRI scan, mainly including degenerative arthrosis or patellar chondromalacia to explain the patients continued pain. Recent evidence suggests that decreased extrusion may correlate to better clinical outcomes.18. 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.

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