The meniscal repair is intact. the menisci of the knees. 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. 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. 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. We hope you found our articles This emphasizes the importance of baseline MRI comparison for evaluation of the postoperative meniscus.3. 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. Associated anomalies in a discoid medial There is no telling how much this error rate will change for radiologists less experienced with MRI. The lateral meniscus is produced by the varus tension and tibial IR. Stay up to date with the latest in Practical Medical Imaging and Management with Applied Radiology. 2008;191(1):81-5. Discoid lateral meniscus. Methods Eighteen patients who had arthroscopically confirmed partial MMPRTs were included. Youderian A, Chmell S, Stull MA. Shepard et al have done a nice job of telling us just how frequently this mistake can be made by fellowship trained musculoskeletal radiologists. However, clinically significant tears that can mechanically impinge were unlikely to have been missed. ligaments and menisci causing severe knee dysplasia in TAR syndrome. tissue only persists at the edges, where differentiation into the asymptomatic, although there is a greater propensity for discoid menisci 70 year-old female with history of medial meniscus posterior horn radial tear. The lateral meniscus is more circular, and its anterior and posterior horns are nearly equivalent in size in cross section. 36 year old male with history of meniscus surgery 7 years ago. This is because most tears occur in the posterior horns [, Whether a torn meniscus is reparable depends on the type or pattern of tear, its location, and the quality of the meniscal tissue. 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 horn is always larger than the anterior horn. 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. discoid meniscus, although discoid medial menisci can occur much less Most studies have shown increased accuracy for direct and indirect MR arthrography compared to conventional MRI for partial meniscectomies of 25% or more.16. Midterm results in active patients. Of the 54 participants, 5 had PHLM tears and 49 were normal. 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). This is a well-done study with clinical correlation and adequate follow-up. are reported cases of complete absence of the medial meniscus as The posterior root of the lateral meniscus (PRLM) attaches along the posterior aspect of the intercondylar eminence of the tibia (Fig. may simulate a peripheral tear (Figure 6).23 The only Connolly B, Babyn PS, Wright JG, Thorner PS. A recurrent tear was proved at second look arthroscopy. When the cruciate of the menisci can be summarized as providing: Clark and Ogden studied the natural development of the menisci in the Examination of the knee showed a mild effusion, 1+ Lachman, positive Pivot shift, and mild tenderness to both medial and lateral joint lines. 7.2 Medial and Lateral Menisci Medial meniscus is larger than the lateral meniscus and is more "open" (=less C-like) and less wide. A meniscal allograft transplant frequently leads to significant improvements in pain and activity level and hastens the return to sport for most amateur and professional athletes.13 A common method of meniscal allograft transplant includes a cadaveric meniscus (fresh or frozen) attached by its anterior and posterior roots to a bone bridge with a trapezoidal shape harvested from a donor tibia. They may not even be apparent with an arthroscopic examination. Skeletal radiology. meniscus are not uncommon; they include an anomalous insertion of the Increased intrameniscal signal is commonly seen in the transplanted allograft but does not correlate with clinical outcome. Diagnosis - clinical presentation with exclusion of advanced knee osteoarthritis. Shepard and colleagues at UCLA specifically analyzed this by reviewing 947 consecutive MRIs. Normal course and intensity of both cruciate ligaments. For DSR inquiries or complaints, please reach out to Wes Vaux, Data Privacy Officer, Description. intra-articular structures at 8 weeks gestation. Repair devices including arrows, darts and sutures are used to approximate the torn edges of the meniscus. No paralabral cyst. The meniscus is two crescent-shaped, thick pieces of cartilage that sit in the knee between the tibia and the femur. Clark CR, Ogden JA. collapse and widening of the medial joint space (Figure 7). If a meniscus tear shows up on a MRI, it is considered a Grade 3. Type ligaments are absent, most commonly the anterior cruciate ligament (ACL) In contrast to the medial meniscus, the posterior horn of the lateral meniscus is additionally secured by the meniscofemoral ligaments (MFL). When bilateral, they are usually symmetric. On examination, there was marked medial joint line tenderness and a large effusion. Direct intraarticular injection of 20-50 mL of dilute iodinated contrast is performed with rapid image acquisition using multidetector CT with high spatial resolution and multiplanar reformatted images. this may extend to to the mid body." is this a bucket tear? Development of the menisci of the human knee Longitudinal lateral meniscus tear status post repair (arrow). 2006;239(3):805-10. 2005; 234:5361. Report On MRI, they resemble radial tears, with a linear cleft of abnormal signal seen at the free edge. 10 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. The meniscus may also become hypertrophic. Pagnani M, Cooper D, Warren R. Extrusion of the Medial Meniscus. After failing conservative management with NSAIDs, PT, and activity modification, he underwent an MRI. They divide the meniscus into superior and inferior halves (Fig. meniscal injury. The Wrisberg variant may present with a While they can arise from a number of mechanisms, root tears are generally thought to be chronic 5. Discoid medial menisci are much less common than discoid lateral menisci,24 and they may be bilateral. This case features the following signs of meniscal tear: Case courtesy, Prof. Dr. Khaled Matrawy, Professor of radiology, Alexandria university, Egypt. Am J Sports Med 2010; 38:15421548, LaPrade RF, Matheny LM, Moulton SG, James EW, Dean CS. 1). meniscus. Meniscal surgery is common and requires accurate post-operative imaging interpretation to guide the treatment approach. 3. The self-reported complication rate for partial meniscectomy is 2.8% and meniscus repair is 7.6%. However, this conjecture and others pre- highest.13,27,34,42 Tear locations, such as the posterior sented in literature are mostly speculative. Fat supressed coronal proton density-weighted (19C, D) and sagittal proton density-weighted (19E) images demonstrate postoperative changes from interval posterior horn partial meniscectomy with a thin rim of posterior horn remaining (arrow) and subchondral fractures in the medial femoral condyle and medial tibial plateau (arrowheads) with marked progression of full-thickness chondral loss in the medial compartment and extruded meniscal tissue. 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. To provide the highest quality clinical and technology services to customers and patients, in the spirit of continuous improvement and innovation. 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 ]. medial meniscus, discoid lateral meniscus, including the Wrisberg The tear was treated by partial meniscectomy at second surgery. While this test will show a tear up to 90% of the time, it does not always. 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. 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. Type 1: A complete slab of meniscal tissue with complete tibial coverage. Healed peripheral medial meniscus posterior horn repair and new longitudinal tear in a different location. rim circumferentially, anteriorly, and posteriorly,19 which Case study, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-75066. Extrusion is commonly seen following root repair. Concise, to-the-point text covers MRI for the entire musculoskeletal system, presented in a highly templated format. The common insertion of the anterior cruciate ligament (ACL) and the AHLM root may provide a pathway for disease. ; Lee, S.H. The posterior root lies anterior to the posterior cruciate ligament. They found that 76 (8%) of these indicated a tear of the anterior horn of either the medial or lateral meniscus. Clinical History: An 18 year-old male with a history of a posterior horn medial meniscus peripheral longitudinal tear treated with meniscal repair at age 16 presents for MR imaging. Irrespective of the repair approach or repair devices used, diagnostic criteria for a recurrent tear remains the same fluid signal or contrast extending into the meniscal substance. Lee S, Jee W, Kim J. MRI: When you tear your meniscus, a magnetic resonance imaging (MRI) scan will show the injury as white lines on black. Another MRI was later performed due to worsening symptoms, and demonstrated a bucket-handle tear with complete anterior luxation of the posterior horn of the left lateral meniscus (Figs. was saddle shaped. Most patients are asymptomatic, but injury to the meniscus can On the sagittal fat-suppressed T2-weighted image (7B), fluid extends into the tear. Tolo VT. Congenital absence of the menisci and cruciate ligaments of the knee: A case report. Lateral Meniscus: Anatomy The lateral meniscus is seen as a symmetric bow tie in the sagittal plane on at least one or two sections before it divides into two asymmetric triangles near the midline. medial meniscus, and not be confined to the ACL as seen in an ACL tear. Disadvantages include patient discomfort, increased cost, physician time needed for the procedure and radiation exposure during fluoroscopy. posterior horn usually measures 12 mm to 16 mm in the sagittal plane in Repair of posterior root tears are being performed with increased frequency over the past several years. 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. 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). Twenty-one had ACL tears; all those with an PHLM tear had an ACL tear. It can be divided into five segments: anterior horn, anterior, middle and posterior segments, and posterior horn. On MR arthrography, (12B), gadolinium extends through the repair site indicating a tear. 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. Additionally, the postoperative complication of new extensive synovitis is apparent on the axial view (18D). One important reason for such discrepancies is a failure to understand the transverse geniculate ligament of the knee (TGL). 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. However, recognizing these variants is important, as they can They are most frequently seen at the posterior horn of the medial meniscus. 3: The Wrisberg variant, where the meniscus may have a normal You have reached your article limit for the month. The most common location is the anterior horn-body junction of the lateral meniscus and less commonly in the mid posterior horn or root of the medial meniscus. Medial meniscus bucket handle tears can result in a double PCL sign. Extension to the anterior cortex of . (1A) Proton density-weighted, (1B) T2-weighted, and (1C) fat-suppressed T1-weighted MR arthrographic sagittal images are provided. The example above demonstrates the importance of baseline MRI comparison when evaluating the postoperative meniscus. 9 The lateral meniscus is more loosely attached than the medial and can translate approximately 11mm with normal knee motion. Vertical flap (oblique, flap, parrots beak) tears are unstable tears and occur in younger patients. . Ross JA,Tough ICK, English TA. Fukuta S, Masaki K, Korai F. Prevalence of abnormal findings in magnetic resonance images of asymptomatic knees. posterior fascicles and meniscotibial ligament are absent and a high 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 . AJR Am J Roentgenol 211(3):519527, De Smet AA. in 19916. Knee Surg Sports Traumatol Arthrosc 2011; 19:147157, Gwathmey F.W., Golish S.R., Diduch D.R., et al: Complications in brief: meniscus repair. Shepard et al conclude that with a 74% false-positive rate, anterior horn tears should be treated surgically only if clinical correlation exists. 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. On the proton density-weighted image (12A) persistent high signal extends to the tibial and femoral surfaces (arrow). pretzels dipped in sour cream. When interpreting MR images of the knee, it is important to assess for any change from the expected shape of the menisci. . mesenchymal mass that differentiates into the tibia, femur, and There was no evidence of meniscal extrusion or a meniscal ghost sign (Fig. 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. An intact meniscal repair was confirmed at second look arthroscopy. On examination, the patient had medial joint line tenderness with positive McMurray test. Examination showed lateral joint line tenderness and a positive McMurray sign. Kocher MS, Klingele K, Rassman SO. Samoto N, Kozuma M, Tokuhisa T, Kobayashi K. Diagnosis of discoid lateral meniscus of the knee on MR imaging. to the base of the ACL or the intercondylar notch. Both the healed peripheral tear and the new central tear were proved at second look arthroscopy. Radiology. Both ligaments attach distally to the posterior horn of the lateral meniscus and contribute to posterior drawer stability . 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. occur with minor trauma. Variations in meniscofemoral ligaments at anatomical study and MR imaging. The anterior and posterior sutures are shuttled down the tibial tunnel (arrowhead). Discoid lateral meniscus: Prevalence of peripheral rim instability. Dickhaut SC, DeLee JC. 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. ligament, and the posterior horn may translate or rotate due to The insertion site Analytical, Diagnostic and Therapeutic Techniques and Equipment 13. 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). is affected. Posterior root repair (Figure 16) is being performed with increasing frequency and has been shown to have better outcomes and decreased risk of osteoarthritis compared to posterior root tears treated non-operatively. The meniscus can separate from the joint capsule or tear through the allograft. The example above illustrates marked degenerative changes caused by loss of meniscal function. Root tears are associated with a high risk for osteoarthritis. The patient underwent partial medial meniscectomy and ACL reconstruction. Monllau et al in 1998 proposed adding a fourth type, (PubMed: 17114506), BakerJC, FriedmanMV, RubinDA (2018) Imaging the postoperative knee meniscus: an evidence-based review. 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. 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. 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 MRI revealed a vertical flap (oblique) tear of the medial meniscus. Kaplan EB. AJR American journal of roentgenology. Recent evidence suggests that decreased extrusion may correlate to better clinical outcomes.18. described in thrombocytopenia absent radius syndrome (TAR syndrome).2,3 Bilateral hypoplasia of the medial meniscus has also been reported.4. Of the 14 athletes, 8 repairs were performed, 5 patients . 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. The posterior root of the medial meniscus attaches to the tibia, just anterior and medial to the posterior cruciate ligament (PCL). The anterior horn inserts on the tibia and continues laterally to the anterior horn of the lateral meniscus via the transverse intermeniscal ligament. As visualized on sagittal MR images, the anterior horn of the medial meniscus is shorter than the posterior horn, whereas the anterior and posterior horns of the lateral meniscus are of equal length. 300). The most important clinical concern at the time of MRI imaging is often high-grade articular cartilage loss. MR imaging evaluation of the postoperative knee. Type 2: An incomplete slab of meniscal tissue with 80% coverage of the lateral tibial plateau. Evaluation of postoperative menisci with MR arthrography and routine conventional MRI. For root tears in general, sagittal imaging may demonstrate a meniscal ghost sign. 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. On the sagittal proton density-weighted image (11A), signal contacts the tibial surface. treatment for stable complete or incomplete types of discoid lateral 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 . Indications for meniscal repair typically include posttraumatic peripheral (red zone) longitudinal tears located near the joint capsule, ideally in younger patients (less than 40). On this page: Article: Epidemiology Pathology Radiographic features History and etymology anterior horn of the medial meniscus into the anterior cruciate ligament as at no time in development does the meniscus have a discoid Kelly BT, Green DW. The purpose of our study was to determine if cysts of the ACL are the origin of cysts adjacent to the AHLM. The fat-suppressed sagittal T1-weighted post arthrogram view (7C) demonstrates gadolinium extending into the meniscal substance. Sagittal T2-weighted image (10B) reveals no fluid at the repair site. Tears can be characterized by length, depth, shape, gap, displacement, stability, dysplasia (discoid) At the time the case was submitted for publication Mostafa El-Feky had no recorded disclosures. 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. Following partial meniscectomy, the knee is at increased risk for osteoarthritis. According to these authors, increased signal to the surface on only one slice should be interpreted as a possible tear. Cases of only one abnormal slice correlated to tears at arthroscopy 55 % of the time for the medial meniscus and 30 % for the lateral [, Accuracy of diagnosing meniscus tear with these criteria has been good. Normal shape and signal of the horns of the medial meniscus, with no evidence of tears or degenerations seen. Total meniscectomy is rarely performed unless the meniscus is so severely damaged that no salvageable meniscal tissue remains.

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