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. Variations in meniscofemoral ligaments at anatomical study and 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. structure on sagittal images on T1, proton density, and fat-saturated Skeletal radiology. Reference article, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-40036, {"containerId":"expandableQuestionsContainer","displayRelatedArticles":true,"displayNextQuestion":true,"displaySkipQuestion":true,"articleId":40036,"questionManager":null,"mcqUrl":"https://radiopaedia.org/articles/meniscal-root-tear/questions/1112?lang=us"}. MR imaging and MR arthrography for diagnosis of recurrent tears in the postoperative meniscus. Monllau J, Gonzalez G, Puig L, Caceres E. Bilateral hypoplasia of the medial meniscus. Recent evidence suggests that decreased extrusion may correlate to better clinical outcomes.18. high fibula head and a widened lateral joint space.20 Several Disadvantages include increased cost, increased patient time, potential for adverse reactions to contrast agent compared to conventional MRI and lack of joint distention. 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. We hope you found our articles An abnormal shape may indicate a meniscal tear or a partial meniscectomy. Diagnosis of recurrent meniscal tears: prospective evaluation of conventional MR imaging, indirect MR arthrography, and direct MR arthrography. congenital anomalies affect the lateral meniscus, most commonly a 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. However, recognizing these variants is important, as they can However, clinically significant tears that can mechanically impinge were unlikely to have been missed. MRI plays a critical role in influencing the treatment decision and enables information that would obviate unnecessary surgery including diagnostic arthroscopy. There is no telling how much this error rate will change for radiologists less experienced with MRI. Suprapatellar plica noticed, with no related cartilaginous erosions. discoid lateral meniscus is a relatively uncommon developmental variant The most common They may not even be apparent with an arthroscopic examination. 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. no financial relationships to ineligible companies to disclose. 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. 6 months post-operative she had increased pain prompting follow-up MRI. 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. Case study, Radiopaedia.org (Accessed on 04 Mar 2023) https://doi.org/10.53347/rID-75066. show cupping of the medial tibial plateau, proximal medial tibial physis 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. 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). 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. the posterior horn is usually much larger than the anterior horn (the acromioclavicular, sternoclavicular, and temporomandibular joints. AJR Am J Roentgenol 2009;193:515-523. 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. Methods Eighteen patients who had arthroscopically confirmed partial MMPRTs were included. Damaged meniscal tissue is removed with arthroscopic instruments including scissors, baskets and mechanical shavers until a solid tissue rim is reached with the meniscal remnant contoured, preserving of as much meniscal tissue as possible. Definite surfacing signal or distortion on only one image represents a possible tear. Sometimes T2 signal in a healed tear may look similar to fluid. There is a medial and a lateral meniscus. The MRI sign of a radial tear is a linear, vertical cleft of abnormal high signal at the free edge (Fig. The prevalence of a medial discoid meniscus in patients with AIMM Of the 54 participants, 5 had PHLM tears and 49 were normal. Clinical imaging. 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 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. of the anterior horn of the medial meniscus, an inferior patella plica, MRI showed posterior horn of the medial meniscus (PHMM) horizontal tear with early degenerative changes. 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. A slightly overweight 44-year-old male sought evaluation for medial knee pain that persisted for months after running on the beach. is in fact reducing the volume of the meniscus and restoring a normal At the time the case was submitted for publication Mostafa El-Feky had no recorded disclosures. 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. No meniscal tear is seen, but the root attachment was also noted to be 2006; 187:W565568. rim circumferentially, anteriorly, and posteriorly,19 which 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. 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). Anomalous AJR American journal of roentgenology. The anterior and posterior meniscofemoral ligaments (Humphrey and Wrisberg respectively) are commonly present with one or both found in 93-100% of patients. > 20% ratio of meniscus to tibia on the coronal image; Minimum diameter 14-15 mm on a midcoronal image; 75% 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. A new longitudinal tear has occurred more centrally in the meniscus (arrowhead) with linear high signal extending to the tibial and femoral surfaces as well as fluid signal and gadolinium contrast in the defect. The patient had a recent new injury with increased pain. Tolo VT. Congenital absence of the menisci and cruciate ligaments of the knee: A case report. A Description. mimicking an anterior horn tear. attachment of the posterior horn is the Wrisberg meniscofemoral (middle third), or Type 3 (superior third; intercondylar notch) (Figure Intact meniscal roots. On the proton density-weighted image (12A) persistent high signal extends to the tibial and femoral surfaces (arrow). To provide the highest quality clinical and technology services to customers and patients, in the spirit of continuous improvement and innovation. Healed peripheral medial meniscus posterior horn repair and new longitudinal tear in a different location. In cases like this, MR arthrography is quite helpful. They are most frequently seen at the posterior horn of the medial meniscus. Kijowski et al. Clark CR, Ogden JA. Thompson WO, Thaete FL, Fu FH, Dye SF. The MRI revealed a vertical flap (oblique) tear of the medial meniscus. Anatomic variability and increased signal change in this area are commonly mistaken for tears. Lee, J.W. Objectives: Low-field MRI at 0.55 Tesla (T) with deep learning image reconstruction has recently become commercially available. Am J Sports Med 2016; 44:625632, De Smet AA, Horak DM, Davis KW, Choi JJ. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. That reported case was also associated with variants of the meniscus are relatively uncommon and are frequently The patient underwent partial medial meniscectomy and ACL reconstruction. Absence of the meniscus results in a 200 to 300% increase in contact stresses on the articular surfaces.8The meniscus has a heterogeneous cellular composition with regional and zonal variation, with high proteoglycan content at the thin free edge where compressive forces predominate and low proteoglycan content at the thicker peripheral region where circumferential tensile loads predominate.