The torn edges are aligned, and stable fixation applied with sutures or bioabsorbable implants at approximately 5 mm intervals. Kaplan EB. AJR Am J Roentgenol 2009;193:515-523. Case study, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-75066. MR arthrogram fat-suppressed sagittal T1-weighted image (11C) shows no gadolinium in the repair. MRI appearance of Wrisberg variant of discoid lateral meniscus. The sutures are tied over a cortical fixation device or Endobutton (short arrow) with the knee flexed at 90 to secure the root repair. Shepard and colleagues at UCLA specifically analyzed this by reviewing 947 consecutive MRIs. Each meniscus has three main parts, the back (posterior horn), middle (body), and front (anterior horn). 7 Therefore, it is important for the radiologist to be familiar with the appearance of a recurrent tear versus an untorn postoperative meniscus. Sagittal proton density-weighted image (7A) through the medial meniscus demonstrates increased signal extending to the tibial surface (arrow). Normal 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. Meniscal root tears are defined as radial tears located within 1 cm from the meniscal attachment or a bony rootavulsion. Klingele KE, Kocher MS, Hresko MT, et al. Close clinical correlation is advised before recommending surgery based on this finding alone. to tear. Also, the inferior patella plica inserts on the By continuing to use our site, you consent to the use of cookies outlined in our Privacy Policy. Anomalous 300). 6. Objective Parameniscal cysts have a very high association with meniscal tears in all locations except the anterior horn lateral meniscus (AHLM). 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). bilaterally absent menisci reported by Tolo et al,3 the Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. 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. If a horizontal tear involves a long segment of the meniscus, the central fragment may displace centrally from the peripheral portion of the meniscus [, Bucket handle tears (BHT) often cause pain and mechanical symptoms, such as locking, catching, and giving way [. Lee S, Jee W, Kim J. 6 months post-operative she had increased pain prompting follow-up MRI. Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. Pre-operative fat supressed coronal proton density-weighted image (19A) demonstates a posterior root radial tear (arrow). menisci occurs. Discoid lateral meniscus: Prevalence of peripheral rim instability. Stay up to date with the latest in Practical Medical Imaging and Management with Applied Radiology. Of the 54 participants, 5 had PHLM tears and 49 were normal. 2002; 222:421429, Ciliz D, Ciliz A, Elverici E, Sakman B, Yuksel E, Akbulut O. 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 ]. Of the 14 athletes, 8 repairs were performed, 5 patients . CT arthrography may be used to evaluate the postoperative meniscus when MRI is contraindicated. The patient underwent meniscal repair but had recurrent pain prompting repeat MRI 8 months post-operative. Presentation - Middle-older aged individuals, non-traumatic, progressive onset of pain. On the sagittal proton density-weighted image (11A), signal contacts the tibial surface. The Wrisberg variant may present with a that this rare condition is also clinically asymptomatic. There was no evidence of meniscal extrusion or a meniscal ghost sign (Fig. 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 Disadvantages include risks associated with joint injection, radiation exposure and lower contrast resolution compared to MRI, particularly in the extraarticular soft tissues. Additionally, the postoperative complication of new extensive synovitis is apparent on the axial view (18D). On the proton density-weighted image (12A) persistent high signal extends to the tibial and femoral surfaces (arrow). 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. variant, and discoid medial meniscus. 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. Radial tears comprise approximately 15 % of tears in some surgical series [. Methods Eighteen patients who had arthroscopically confirmed partial MMPRTs were included. 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 lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. The medial meniscus is asymmetrical with a larger posterior horn. Fat suppressed sagittal T1-weighted MR arthrogram (5C) demonstrates gadolinium within the tear (arrow). Radiology. 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 . Kim SJ, Moon SH, Shin SJ. Kocher MS, Klingele K, Rassman SO. Am J Sports Med 2010; 38:15421548, LaPrade RF, Matheny LM, Moulton SG, James EW, Dean CS. If the tear does not show, it is considered a Grade 1 or 2 and is not as serious. Analytical, Diagnostic and Therapeutic Techniques and Equipment 13. 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 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 [. 70 year-old female with history of medial meniscus posterior horn radial tear. The MFL was not observed in five (19%) of 26 studies of an LMRT. . It is located in the lateral portion of the knee interior of the knee joint. Davidson D, Letts M, Glasgow R. Discoid meniscus in children: Treatment and outcome. A meniscus is a crescent-shaped fibrocartilaginous structure that The symptoms In these cases, MR arthrography may provide additional diagnostic utility. If missing on MR images, a posterior root tear is present. A tear of the anterior horn of the lateral meniscus is damage to the front part of one of the two structures that act as shock absorbers between the thigh bone and the lower leg, explains The Steadman Clinic. A meta-analysis of 44 trials. Clin Orthop Relat Res 2012; 470: pp. partly divides a joint cavity, unlike articular discs, which completely 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. meniscal injury. To provide the highest quality clinical and technology services to customers and patients, in the spirit of continuous improvement and innovation. . Connolly B, Babyn PS, Wright JG, Thorner PS. 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 . This is a well-done study with clinical correlation and adequate follow-up. typically into the anterior cruciate ligament. attachment of the posterior horn is the Wrisberg meniscofemoral 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. (Tr. 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 . 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. 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. 2. High signal close to fluid intensity contacts the tibial surface on the sagittal T2-weighted image (11B) and is equivocal. Normal Root tears are often large radial tears that extend through the entire AP width of the meniscus. When it involves the posterior root, medial root tears are easier to diagnose than lateral root tears. In children, sometimes an increased signal is seen within meniscus due to increased vascularity, but usually the signal does not contact articular surface. [emailprotected]. The example above demonstrates the importance of baseline MRI comparison when evaluating the postoperative meniscus. pretzels dipped in sour cream. Continuous meniscal tissue bridged the anterior and posterior horns of the lateral meniscus on 3 consecutive sagittal slices (Figure 1B). Schwenke M, Singh M, Chow B Anterior Cruciate Ligament and Meniscal Tears: A Multi-modality Review. At second look arthroscopy, the posterior horn tear was healed and the anterior horn tear was found to be unstable and treated by partial meniscectomy. MRI plays a critical role in influencing the treatment decision and enables information that would obviate unnecessary surgery including diagnostic arthroscopy. Zonal variation is also seen in the density of meniscus cells and their phenotypes with a chondrocytic inner zone and fibroblastic outer zone. Anatomic variability and increased signal change in this area are commonly mistaken for tears. reported.4. 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). The medial meniscus is more tightly anchored than the lateral meniscus, allowing for approximately 5mm of anterior-posterior translation. While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. Radial Tear of the Medial Meniscal Root: Reliability and Accuracy of MRI for Diagnosis. In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). 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. Repair of posterior root tears are being performed with increased frequency over the past several years. Intensity of signal contacting meniscal surface in recurrent tears on MR arthrography compared with that of contrast material. The condition is typically asymptomatic and, therefore, is infrequently diagnosed.14 Lateral meniscal variant with absence of the posterior coronary ligament. ligament, and the posterior horn may translate or rotate due to 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. Both horns of the medial meniscus are triangular with sharp points. Become a Gold Supporter and see no third-party ads. MR imaging is useful for evaluation of many possible complications following meniscal surgery. 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. 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. ligaments and menisci causing severe knee dysplasia in TAR syndrome. The purpose of our study was to determine if cysts of the ACL are the origin of cysts adjacent to the AHLM. 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. 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. The location of meniscal tears or signal alterations (anterior/posterior horn or body of the medial/lateral meniscus) and the grade (normal/intra-substance signal abnormality = 0 and tear = 1) were determined on 2D . Suprapatellar plica noticed, with no related cartilaginous erosions. On medial posterior root tears there is often 2: On posterior root radial tears of the lateral meniscus, the appearance may be similar to radial tears in other locations. 2006;239(3):805-10. A tear of the lateral meniscus can occur from a sudden injury, or from chronic wear and overload. 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. Repair devices including arrows, darts and sutures are used to approximate the torn edges of the meniscus. problem in practice. Results: Arthroscopic examination of the anterior horn of the lateral meniscus in all 22 patients was normal. The anterior and posterior meniscofemoral ligaments (Humphrey and Wrisberg respectively) are commonly present with one or both found in 93-100% of patients. Biologic augmentation with application of exogenous fibrin clot or growth factors may be combined with the repair to promote healing. 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 ]. MRI Findings: Medial meniscus: Tear of the posterior horn seen to the inferior articular surface continuing into the posterior body and becoming more vertical. 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. The sagittal proton density-weighted image (13A) demonstrates linear high signal extending to the femoral and tibial surfaces (arrow). A recurrent tear was proved at second look arthroscopy. Best assessed on T2 weighted sequences. In the previously reported cases, as well as in this case, the At the time the article was last revised Yahya Baba had Lateral meniscus bucket handle tears can produce the double anterior horn sign or double ACL sign. intra-articular structures at 8 weeks gestation. Meniscal tears are common and often associated with knee pain. After failing conservative management with NSAIDs, PT, and activity modification, he underwent an MRI. Type 1: A complete slab of meniscal tissue with complete tibial coverage. Atypically thick and high location A displaced longitudinal tear is a "bucket handle" tear. MRI features are consistent with torn lateral meniscus with flipped anterior horn superomedial and posterior, resting superior to the posterior horn. the rare ring-shaped meniscus, to the classification. meniscus are not uncommon; they include an anomalous insertion of the How I Diagnose Meniscal Tears on Knee MRI. Monllau et al in 1998 proposed adding a fourth type, A detached posterior root is functionally equivalent to a total meniscectomy with loss of its ability to withstand hoop stress. 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. discoid meniscus, although discoid medial menisci can occur much less 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. in 19916. 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. The patient underwent partial medial meniscectomy and ACL reconstruction. anterior horn of the medial meniscus into the anterior cruciate ligament 2a, 2b, 2c). Sagittal T2-weighted image (10B) reveals no fluid at the repair site. joint: Morphologic changes and their potential role in childhood Diagnostic performance is decreased following partial meniscectomy since the standard criteria used to diagnose a meniscus tear cannot be applied to the post-operative meniscus.3,4,5,6 Partial meniscectomy may distort the normal morphology of the meniscus and increased meniscal signal intensity may extend to the articular surface when a portion of the meniscus has been resected, simulating a tear. discoid lateral meniscus, including a propensity for tears to occur and Following partial meniscectomy, the knee is at increased risk for osteoarthritis. Figure 7: Meniscofemoral ligament. What is a Lateral Meniscus Tear? The meniscus is two crescent-shaped, thick pieces of cartilage that sit in the knee between the tibia and the femur. AJR Am J Roentgenol. collapse and widening of the medial joint space (Figure 7). an adult), and approximately twice the size of the anterior horn on 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. include hypoplastic menisci, absent menisci, anomalous insertion of the In this section, the major patterns of tears are described and depicted in MRIs and arthroscopy images. 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. An intact meniscal repair was confirmed at second look arthroscopy. Recent evidence suggests that decreased extrusion may correlate to better clinical outcomes.18. signal fluid cleft interposed between the posterior horn and the capsule 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. The posterior root lies anterior to the posterior cruciate ligament. Studies on meniscus root tears have investigated the relationship of osteoarthritis and an anterior cruciate ligament tear. Sagittal proton density-weighted image (9A) demonstrates no high signal abnormality. snapping knee due to hypermobility. Collagen fibers are arranged for transferring compressive loads into circumferential hoop stresses, secured by radially oriented tie fibers. Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. Dr. Diduch, Associate Professor, Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA, is Editor of Sports Medicine Reports. The lateral meniscus is one of two fibrocartilaginous menisci of the knee. The example above illustrates marked degenerative changes caused by loss of meniscal function. structure on sagittal images on T1, proton density, and fat-saturated The knee is a complex synovial joint that can be affected by a range of pathologies: ADVERTISEMENT: Supporters see fewer/no ads, Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. Grade II hyperintense horizontal signal of posterior horn of medial meniscus is noted. (as previously described), meniscal cyst,26 discoid lateral meniscus in the same knee (Figure 9),25 and pathologic medial patella plica.27. both enjoyable and insightful. The menisci are C-shaped fibrocartilaginous structures composed of radial and circumferential collagen fibers that have several roles, including joint stabilization, load distribution, articular cartilage protection and joint lubrication. Skeletal radiology. Discoid medial meniscus. : Complications in brief: arthroscopic partial meniscectomy. Surgery is useful if they are unstable and flipping in and out of the joint causing pain. When the cruciate small meniscus is also seen in the wrist joint. 2014; 43:10571064, McCauley TR. The patient underwent an all-inside lateral meniscus repair. 1 ). is affected. 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. The MRI also demonstrated moderate degenerative spurring at the lateral joint compartment, a large knee joint effusion with . Media community. For partial meniscectomies involving 25% or more, conventional MRI has lower accuracy. Anterior tibial marrow edema and organized trabecular fracture measuring 16 mm AP, 18 mm transverse. 800-688-2421. However, many clinicians opt to use conventional MRI as the initial postoperative imaging study and reserve MR arthrography for equivocal cases. Definite surfacing signal or distortion on only one image represents a possible tear. Exam showed a mild effusion and medial joint line tenderness. Magnetic resonance imaging of the postoperative meniscus: resection, repair, and replacement. We will review the common meniscal variants, which 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. Type 2: An incomplete slab of meniscal tissue with 80% coverage of the lateral tibial plateau. congenital absence of the cruciate ligaments. An athletic 52-year-old male, who was an avid runner all his adult life, presented with medial pain and a popping sensation in knee. The medial compartment articular cartilage is preserved, and the meniscal body is not significantly extruded (16D). Complex or deep radial tears were found in three of five cases of lateral meniscus extrusion and normal root. Problems encountered in a discoid medial meniscus are the same as a 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). noted to be diminutive, with the posterior horn measuring 7 mm to 8 mm. Arthroscopy revealed a horizontal tear of PHMM, and a partial medial meniscectomy was performed. measurements of the posterior horn of the medial meniscus may vary, but The camera can visualize the meniscus and other structures within the knee. 2005; 234:5361. ligament and meniscal fascicles. medial meniscus, and not be confined to the ACL as seen in an ACL tear. Radiographs may Knee Surg Sports Traumatol Arthrosc 2011; 19:147157, Gwathmey F.W., Golish S.R., Diduch D.R., et al: Complications in brief: meniscus repair. Generally, 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). Indications for meniscal repair typically include posttraumatic peripheral (red zone) longitudinal tears located near the joint capsule, ideally in younger patients (less than 40). Brody J, Lin H, Hulstyn M, Tung G. Lateral Meniscus Root Tear and Meniscus Extrusion with Anterior Cruciate Ligament Tear. Is sport activity possible after arthroscopic meniscal allograft transplantation? No meniscal tear is seen, but the root attachment was also noted to be On examination, the patient had medial joint line tenderness with positive McMurray test. On MR arthrography, (12B), gadolinium extends through the repair site indicating a tear. On MRI, longitudinal tears appear as a vertical line of abnormal signal contacting articular surface. posterior fascicles and meniscotibial ligament are absent and a high A ; Lee, S.H. of the menisci can be summarized as providing: Clark and Ogden studied the natural development of the menisci in the mimicking an anterior horn tear. 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 posterior cruciate ligament is intact. Longitudinal medial meniscus tear managed by repair (arrow). Tears There is no telling how much this error rate will change for radiologists less experienced with MRI. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. 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. pivoting). Healed peripheral medial meniscus posterior horn repair and new longitudinal tear in a different location. Findings indicate an intact meniscus following partial meniscectomy with normal intrameniscal signal. 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.