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Local-area cartilage segmentation (LACS) software was developed to segment medial femur (MF) cartilage on magnetic resonance imaging (MRI). Our objectives were 1) to extend LACS to the lateral femur (LF), medial tibia (MT), and lateral tibia (LT), 2) to compare LACS to an established manual segmentation method, and 3) to visualize cartilage responsiveness over each cartilage plate.Osteoarthritis Initiative participants with symptomatic knee osteoarthritis (OA) were selected, including knees selected at random (n = 40) and knees identified with loss of cartilage based on manual segmentation (Chondrometrics GmbH), an enriched sample of 126 knees. LACS was used to segment cartilage in the MF, LF, MT, and LT on sagittal 3D double-echo steady-state MRI scans at baseline and at 2-year follow-up. We compared LACS and Chondrometrics average thickness measures by estimating the correlation in each cartilage plate and estimating the standardized response mean (SRM) for 2-year cartilage change. We illustrated cartilage loss topographically with SRM heatmaps.The estimated correlation between LACS and Chondrometrics measures was r = 0.91 (95% confidence interval [95% CI] 0.86, 0.94) for LF, r = 0.93 (95% CI 0.89, 0.95) for MF, r = 0.97 (95% CI 0.96, 0.98) for LT, and r = 0.87 (95% CI 0.81, 0.91) for MT. Estimated SRMs for LACS and Chondrometrics measures were similar in the random sample, and SRM heatmaps identified subregions of LACS-measured cartilage loss.LACS cartilage thickness measurement in the MF and LF and tibia correlated well with established manual segmentation-based measurement, with similar responsiveness to change, among knees with symptomatic knee OA. LACS measurement of cartilage plate topography enables spatiotemporal analysis of cartilage loss in future knee OA studies.

Purpose Trochlear dysplasia (TD) is a developmental condition and classified in to four types by Dejour. Patients with TD are more likely to have anterior cruciate ligament (ACL) injury. Increased ACL loading caused by TD may result in ACL-mucoid degeneration (MD). The purpose of this study was to evaluate the presence of ACL-MD in patients with TD and investigate whether there was a correlation between ACL-MD and TD grade and tibial tuberosity-trochlear groove (TT-TG) distance. Materials and Methods Knee MR examinations of one hundred five patients with TD were included in this study. TD was graded according to Dejour (type A, B, C, and D), and Lippacher classification (low and high grade). TT-TG distance was also measured (15 mm considered as normal). Then ACL was assessed on MRI sequences for MD. Criteria for ACL-MD were thickened ACL with increased signal intensity on all MR sequences. Results Among 105 patients with TD, 35 patients (33,3%) had ACL-MD. One-half of the ACL-MD was noted in knees with type A TD (50,0%). According to Lippacher classification, one half of the patients with low-grade dyspslasia had ACL-MD (50,0%). There was also a positive correlation between ACL-MD and TT-TG distance. Conclusion TD and patellar instability are significant risk factors for ACL-MD. Due to the high prevelance of ACL-MD with TD we advised the preoperative evaluation of ACL with knee MRI.

Early investigations into the magnetic resonance imaging (MRI) appearance of articular cartilage imaging relied on assessment of the morphology, with subsequent investigators reporting identifying increased T2 signal intensity, bright signal, in degenerated cartilage. The cartilage “black line sign” is a finding that has recently been described in the radiology literature to characterize cartilage pathology. This sign refers to a focal linear hypointense signal within articular cartilage that is oriented perpendicular to the subchondral bone on T2-weighted MRI. The diagnostic significance and clinical relevance of this sign is debated. Since its first description, several papers have further delineated the etiology, prevalence, and clinical relevance of these and other dark cartilage abnormalities. The intent of this article is to summarize these findings, with hopes of bringing to light the importance of dark cartilage lesions and their clinical implication in the world of knee surgery. We will briefly discuss the most probable etiologies of dark cartilage abnormalities and the major factors determining the unique signal intensity. The described anatomical patterns of this finding, the clinical importance, potential mimics, and current treatment recommendations will be reviewed.

Introduction: The integrity of articular cartilage determines the functional state of the joint. In recent years, the development of MRI sequences of various articular cartilage has become the focus of many research topics. Objective: The accuracy of diagnosis of knee cartilage injury caused by motion injury was studied retrospectively by meta-three-dimensional software. Methods: Forty-six knee joints of 45 patients with sports injuries, multi-sequence MRI was performed before surgery, including conventional knee MRI (SET1WI, FSEPD/T2WI), 3D SPGR, and 3D FIESTA sequences. Results: According to the operation results, the sensitivity, specificity, positive predictive value, and negative predictive value of 3D SPGR combined with conventional MRI sequence evaluation of cartilage damage are the highest, 73%, 98%, 95%, and 90%. Conclusions: 3D SPGR combined with conventional MRI sequences can improve accurate evaluation and diagnosis of cartilage disease over a reasonable scan time. Level of evidence II; Therapeutic studies - investigation of treatment results. RESUMO Introdução: A integridade da cartilagem articular determina o estado funcional da articulação. Nos últimos anos, o desenvolvimento de sequências de ressonância magnética de várias cartilagens articulares se tornou o foco de muitos tópicos de pesquisa. Objetivo: A precisão do diagnóstico de lesão da cartilagem do joelho causada por lesão de movimento foi estudada retrospectivamente por software meta-tridimensional. Métodos: Quarenta e seis articulações de joelho de 45 pacientes com lesões esportivas, várias sequências de ressonância magnética foram realizadas antes da cirurgia, incluindo ressonância magnética de joelho convencional (SET1WI, FSEPD / T2WI), 3D SPGR e sequências 3D FIESTA. Resultados: De acordo com os resultados da operação, a sensibilidade, especificidade, valor preditivo positivo e valor preditivo negativo de 3D SPGR combinado com avaliação de sequência de ressonância magnética convencional de danos na cartilagem são os mais altos, 73%, 98%, 95% e 90%. Conclusões: 3D SPGR combinado com sequências convencionais de ressonância magnética pode melhorar a avaliação precisa e diagnóstico de doença da cartilagem em um tempo de varredura razoável. Nível de evidência II; Estudos terapêuticos- investigação dos resultados do tratamento. RESUMEN Introducción: La integridad del cartílago articular determina el estado funcional de la articulación. En los últimos años, el desarrollo de secuencias de resonancia magnética de varios cartílagos articulares se ha convertido en el foco de muchos temas de investigación. Objetivo: La precisión del diagnóstico de la lesión del cartílago de la rodilla causada por una lesión por movimiento se estudió retrospectivamente mediante un software meta-tridimensional. Métodos: Cuarenta y seis articulaciones de rodilla de 45 pacientes con lesiones deportivas, se realizó una resonancia magnética de secuencia múltiple antes de la cirugía, incluida la resonancia magnética de rodilla convencional (SET1WI, FSEPD/T2WI), secuencias 3D SPGR y 3D FIESTA. Resultados: De acuerdo con los resultados de la operación, la sensibilidad, la especificidad, el valor predictivo positivo y el valor predictivo negativo de 3D SPGR combinados con la evaluación de la secuencia de resonancia magnética convencional del daño del cartílago son los más altos, 73%, 98%, 95% y 90%. Conclusiones: 3D SPGR combinado con secuencias de resonancia magnética convencionales puede mejorar la evaluación y el diagnóstico precisos de la enfermedad del cartílago en un tiempo de exploración razonable. Nivel de evidencia II; Estudios terapéuticos- investigación de los resultados del tratamiento.

PURPOSE: To determine the relationship between femoral–tibial morphometries and anterior cruciate ligament (ACL) pathologies using magnetic resonance imaging (MRI). METHODS: We retrospectively evaluated 455 patients (211 females and 244 males) who underwent knee MRI with suspected ACL pathology. Imaging findings were classified as normal ACL (n = 119), degeneration of the ACL (n = 116), partial ACL tear (n = 103), and complete ACL tear (n = 117). In all groups, the femoral intercondylar notch width (INW), intercondylar distance (CD), notch width index (NWI), and intercondylar notch angle (INA), the angles between the tibial plateau and tibial spines (MPA and LPA), intercondylar eminence peak angle (IEA), and tibial slope angles (MSA and LSA) were measured. RESULTS: Femoral INW and NWI were significantly lower in patients with ACL pathology (p

Objective: While articular cartilage defects are common incidental findings among adult athletes, the effect of running on the cartilage of adolescent athletes have rarely been assessed. This study aims to assess the variations in the articular cartilage of the knees in healthy adolescent basketball players using quantitative T2 MRI (magnetic resonance imaging). Design: Fifteen adolescent basketball players were recruited (13.8 ± 0.5 years old). Girls were excluded to avoid potential gender-related confounding effects. Players underwent a pre-run MRI scan of both knees. All participants performed a 30-minute run on a treadmill. Within 15 minutes after completion of their run, players underwent a second, post-run MRI scan. Quantitative T2 maps were generated using the echo modulation curve (EMC) algorithm. Pre-run scans and post-run scans were compared using paired t test. Results: Participants finished their 30-minute run with a mean running distance of 5.77 ± 0.42 km. Pre-run scans analysis found statistically significant ( P < 0.05) changes in 3 regions of the knee lateral compartment representing the cartilaginous tissue. No differences were found in the knee medial compartment. Post-run analysis showed lower T2 values in the medial compartment compared to the pre-run scans in several weight-bearing regions: femoral condyle central (pre/post mean values of 33.9/32.2 ms, P = 0.020); femoral condyle posterior (38.1/36.8 ms, P = 0.038); and tibial plateau posterior (34.1/31.0 ms, P < 0.001). The lateral regions did not show any significant changes. Conclusions: Running leads to microstructural changes in the articular cartilage in several weight-bearing areas of the medial compartment, both in the femoral and the tibial cartilage.

This study aimed to investigate the morphological variations in the cross-sectional anatomy of the meniscus between similar-sized matched menisci. Knee MRI of 329 patients with intact menisci were retrospectively reviewed, and the meniscal length (ML), meniscal width (MW), and cross-sectional dimensions (meniscal height and width) of the anterior, posterior horns, and the corpus were measured. Patients with similar-sized menisci who had less than 1 mm difference in ML and MW were matched. 330 male-to-male medial menisci (MM), 623 male-to-male lateral menisci (LM), 82 female-to-female MM, 233 female-to-female LM, 176 cross-gender MM, and 265 cross-gender LM unique combination of ideally matched pairs (total: 1709) were generated. The disparity in the cross-sectional dimensions, absolute difference, and the paired percent differences was statistically analyzed. The ML and MW in all groups were statistically similar, with a predefined absolute difference of 1 mm both for ML and MW (paired percent difference

Place: France; International audience; PURPOSE: The purpose of this study was to assess and compare the prevalence of meniscal, ligament and cartilage lesions on knee MRI in a series of age- and sex-matched patients with and without medial meniscal ossicle.MATERIALS AND METHODS: Forty-two knee MRI examinations obtained in 42 patients (36 men, 6 women; mean age, 42.5±22.2 [SD] years; range: 19-65years) on which a medial meniscal ossicle was present were compared to 42 knee MRI examinations obtained in 42 age- and sex-matched patients (36 men, 6 women; mean age, 41.8±20.6 [SD] years; range: 19-65years) on which no medial meniscal ossicles were present. Two radiologists (R1, R2) blinded to the presence of meniscal ossicle by reading only the fat-saturated intermediate-weighted MR images separately assessed the presence of meniscal, ligament and cartilage lesions on these 84 knee MRI examinations. Prevalence of meniscal and ligament lesions and degree of cartilage degradation at MRI were compared between knees with and those without medial meniscal ossicle.RESULTS: In knees with medial meniscal ossicle, R1 and R2 detected 33 (79%) and 38 (90%) medial meniscal lesions, respectively that involved the posterior root (n=25/32 for R1/R2), the posterior horn (n=19/14 for R1/R2) or the body (n=8/10 for R1/R2). The prevalence of posterior root tear (60% [25/42]/76% [32/42] for R1/R2) and that of anterior cruciate ligament (ACL) lesions (48% [20/42]/57% [24/42] for R1/R2) as well as the medial cartilage degradation score (3.35±0.87 [SD] for R1 and 3.92±0.78 [SD] for R2) were significantly greater in knees with than in knees without medial meniscal ossicle (root lesions: P\textless0.01 for both readers; ACL lesions and medial cartilage score: P\textless0.01 for both readers).CONCLUSION: On MRI examination, knees with a medial meniscal ossicle demonstrate a greater frequency of medial posterior root tear and of ACL lesions and a greater degree of medial femoro-tibial cartilage degradation by comparison with knees without medial ossicle.

Background Bone-cartilage mismatch is a variation in which the surface curvature of the articular cartilage is incongruent with the curvature of the underlying subchondral bone. The purpose of this study is to investigate the prevalence of this variant in the medial tibial plateau (MTP) and examine potential association with clinical findings and intra-articular derangements using MRI. Methods A quantitative and qualitative retrospective analysis of 98 knee MRI studies was performed. Bone and cartilage depths of the MTP were measured to assess bone-cartilage morphology and classified into congruent (concave bone-concave cartilage) and incongruent (concave bone-convex cartilage) patterns. Associations between bone-cartilage mismatch and clinical findings and other MRI changes were assessed using Fisher’s exact test. Results By quantitative assessment, four individuals (4%) had MTP incongruent morphology (bone-cartilage mismatch). The mean bone depth ± standard deviation (SD) was 2.3 ± 0.6 mm concave in the congruent group, and 1.4 ± 0.6 mm concave in the incongruent group. The mean cartilage depth ± SD was 0.7 ± 0.7 mm concave in the congruent group, and 0.9 ± 0.5 mm convex in the incongruent group. By qualitative assessment, three individuals (3%) had incongruent morphology. Although not statistically significant, a higher proportion of individuals (3 of 4; 75%) with incongruent cartilage demonstrated chondromalacia patellae compared to those with congruent cartilage (38 of 94; 40%). Conclusion Bone-cartilage mismatch was present in 3–4% of the knees. Individuals with incongruent cartilage demonstrated a trend of a higher proportion of chondromalacia patellae. Larger studies are needed to evaluate this further.

Age estimation is a crucial element of forensic medicine to assess the chronological age of living individuals without or lacking valid legal documentation. Methods used in practice are labor-intensive, subjective, and frequently comprise radiation exposure. Recently, also non-invasive methods using magnetic resonance imaging (MRI) have evaluated and confirmed a correlation between growth plate ossification in long bones and the chronological age of young subjects. However, automated and user-independent approaches are required to perform reliable assessments on large datasets. The aim of this study was to develop a fully automated and computer-based method for age estimation based on 3D knee MRIs using machine learning. The proposed solution is based on three parts: image-preprocessing, bone segmentation, and age estimation. A total of 185 coronal and 404 sagittal MR volumes from Caucasian male subjects in the age range of 13 and 21 years were available. The best result of the fivefold cross-validation was a mean absolute error of 0.67 ± 0.49 years in age regression and an accuracy of 90.9%, a sensitivity of 88.6%, and a specificity of 94.2% in classification (18-year age limit) using a combination of convolutional neural networks and tree-based machine learning algorithms. The potential of deep learning for age estimation is reflected in the results and can be further improved if it is trained on even larger and more diverse datasets.

OBJECTIVE. Cartilage loss on preoperative knee MRI is a predictor of poor outcomes after arthroscopic partial meniscectomy. The purpose of this study was to compare the ability to predict outcomes after arthroscopic partial meniscectomy with a clinically used modified Outerbridge system versus a semiquantitative MRI Osteoarthritis Knee Score system for grading cartilage loss. MATERIALS AND METHODS. Patients who underwent preoperative knee MRI within 6 months of arthroscopic partial meniscectomy and who had outcomes available from the time of surgery and 1 year later were eligible for inclusion. Cases were evaluated by two radiologists and one radiology fellow with the use of both grading systems. The accuracy of each system in discriminating between surgical success and failure was estimated using the ROC curve (AUC) with 95% CIs. A Wald test was used to assess noninferiority of the clinical grading system. Interreader agreement regarding the accuracy of the grading systems in predicting outcomes was also compared. RESULTS. A total of 78 patients (38 women and 40 men; mean age, 56.6 years) were included in the study. A prediction model using clinical grading (AUC = 0.695; 95% CI, 0.566-0.824) was noninferior (p = 0.047) to a model using MRI Osteoarthritis Knee Score grading (AUC = 0.683; 95% CI, 0.539-0.827). Both MRI prediction models performed better than a model using demographic characteristics only (AUC = 0.667; 95% CI, 0.522-0.812). Inter-reader agreement with clinical grading (80.8%) was higher than that with MRI Osteoarthritis Knee Score grading (65.0%; p = 0.012). CONCLUSION. A clinically used system to grade cartilage loss on MRI is as effective as a semiquantitative system for predicting outcomes after arthroscopic partial meniscectomy, while also offering improved interreader agreement.

The aim of this study was to propose and validate a new six-item topographical classification of knee bone marrow lesions in coronal MRI images, to provide an easy-to-use aid to describe their location in a more reproducible and accurate way. This study was conducted in four phases. The first was to do a literature search for methods of describing bone marrow lesions in MRI of the knee. The second was creation of a six-area topographic classification of bone marrow lesions in coronal MRI of the knee. The third phase was selection of cases with bone marrow lesions on knee MRI performed in a single hospital between January of 2017 and December of 2018. The fourth phase was categorization of the bone marrow lesions’ location according to the new proposed classification by three independent examiners, two orthopedic surgeons and one radiologist. Patient’s demographic data and associated lesions were collected. The inter-observer and intra-observer reliability of the proposed classification was then calculated. MRI examination of 4000 patients were studied and in 520 patients a total of 666 bone marrow lesions were identified and their location classified using the new system. The inter-observer and intra-observer reliability analysis found a Fleiss’ Kappa value of 0.96 (0.95–0.97) and 0.97 (0.96–0.97), respectively, confirming the high reproducibility of the proposed classification. The proposed six-location classification of bone marrow lesions is highly reproducible and can help researchers develop studies and share information in a more accurate and reliable way. The correct classification of bone marrow lesions can lead to a more accurate description of this pathology and help clinicians to propose appropriate therapies for this group of patients. V.

Amaç: Patella tiplerindeki farklılıkların, menisküs üzerindeki yükü değiştirerek ve yürüme mekaniğinde değişikliğe neden olarak menisküs rüptürünün etiyolojisinde rol oynayabileceğini düşünüyoruz. Bu çalışmada patella tiplerinin dağılımı ve menisküs rüptürü ile ilişkisi araştırıldı.Materyal ve Metod: Bu çalışmada, Ocak 2017- Temmuz 2018 tarihleri arasında Fizik Tedavi ve Rehabilitasyon polikliniğine başvuran 510 hastanın diz manyetik rezonans (MR) incelemeleri patella tiplerinin ayırımı ve menisküs rüptürünün dağılımı açısından PACS sisteminde retrospektif olarak tekrar değerlendirildi. Hastaların klinik öyküleri, muayene bulguları, yaşları ve cinsiyetleri hastanenin kayıt sisteminden alındı. On sekiz yaş altındaki hastalar, majör travma öyküsü olan ve ameliyat edilen hastalar çalışma dışı bırakıldı. Diz MR incelemesi 3-Tesla magnet gücüne sahip MR cihazı (MagnetomSkyra, Siemens Healthcare, Erlangen, Almanya) ile standart diz koili kullanılarak gerçekleştirildi. Patella tipi sınıflamasında aksiyel PD görüntüleri kullanılarak, Baumgartl ve arkadaşlarının yaptıkları sınıflama esas alındı. Buna göre; Tip I: İçbükey ve eşit uzunluktaki medial ve lateral fasetler. Tip II: Medial faset düz veya içbükeydir, lateral faset medial fasetten daha belirgindir. Tip III: Daha küçük medial faset mevcut ve dışbükeydir. Tip IV: Medial faset veya merkez kenarı yoktur, jokey şapkası olarak adlandırılır. Elde edilen sayısal veriler, yaş, cinsiyet patella tipi ve menisküs yırtılması açısından SPSS 20.0 (SPSSInc., Chicago IL, USA) versiyonu istatistik paket programı kullanılarak işlendi. Bulgular: Çalışmaya alınan 238 (%46,7) kadın, 272 (%53,3) erkek toplam 510 hasta, patella tipi ve menisküs rüptürü açısından değerlendirildi. Hastaların ortalama yaşları 38.83 ± 0.5 idi (en az 18, en çok 76). Tüm hastalarda Tip I patella 132 (%25,9) Tip II 354 (%69,4) Tip III 24 (%4,7) olarak bulundu. 376 hastada, %73,7 oranında menisküs yırtılması tespit edilmedi ve 134 (%26,3) hastada menisküs yırtılması vardı. Menisküs yırtığı olan hastaların 68'i (%50,7) kadın, 66'sı (%49,3) erkekti. Sonuç: Farklı patella tiplerinde simetrik ve simetrik olmayan yükleme sonucu menisküs üzerindeki orantısız veya simetrik olmayan basınç sonucu menisküs rüptürü eğiliminin artacağını düşündük. Ancak çalışmamızda meniskal rüptür ile patella tipleri arasında istatistiksel olarak anlamlı bir ilişki bulamadık.

This article highlights five knee injuries that, in the author's experience, are commonly overlooked by readers inexperienced in knee MRI: ramp lesions, meniscocapsular tears, meniscal root ligament tears, posterior capsular ligament tears, and partial anterior cruciate ligament tears. Although these injuries are readily apparent when the images are assessed for the given abnormality, the author believes they may be overlooked because either the injury is not considered or the affected area is not closely inspected. These injuries may not alter immediate clinical management or require surgical intervention; nevertheless, they may result in patient symptoms and may potentially increase the risk of further knee injury. Moreover, these injuries are difficult to recognize clinically and arthroscopically. This review presents these five injuries, emphasizing relevant anatomy, normal MRI appearances, common injury patterns, and tips to avoid overlooking them. Routine review of these areas when interpreting knee MRI, with additional imaging as necessary, will allow these injuries to be recognized more regularly.

Purpose: This study was conducted in order to evaluate the clinical utility of MRI in detecting cartilage lesions and its dependence on anatomical location and lesion grade. Methods: A retrospective analysis of MRI reports and arthroscopic findings was performed on 190 consecutive patients treated in one orthopaedic department. MRI protocols were prepared by 18 radiologists from 10 different MRI centers with the use of 1.5 T magnets. The image protocols were selected by reading radiologists. Four hundred and fifty-three chondral lesions in five anatomic locations were identified during this study and graded according to the ICRS classification. Sensitivity, specificity, receiver operating characteristic (ROC), and Bangdiwala’s observer agreement charts were utilized to evaluate the diagnostic performance. Results: Only approximately 30% of MRI showed an adequate cartilage status in all anatomical locations. The sensitivity ranged from 92% in healthy cartilage to 5% in grade I lesions. The specificity differed also grossly depending on the lesion grade, reaching 96.5% in grade four lesions and 38% in healthy cartilage. The medial compartment Bangdiwala’s observer agreement charts show a gross underestimation of cartilage lesions, and the area under the curve (AUC) of ROC surpasses 0.7 only in the medial femoral condyle and patella-femoral joint. Overall, the medial compartment accuracy was significantly higher than the lateral compartment. The MRI showed correspondence of its diagnostic performance with cartilage lesion severity. Conclusion: MRI underestimates the extent of cartilage injury and evaluation of cartilage defects based on MRI should be taken with caution by orthopaedic surgeons in planning surgery. Surgical planning on MRI should take cartilage lesions under consideration, even if no cartilage lesions are reported on the MRI.

Background Osteoarthritis (OA) of the knee joint is a common cause of chronic disability in older adults. During the past 10 years, the infrapatellar fat pad (IPFP) has emerged as a new player in the pathogenesis of knee OA. Its exact role in the pathogenesis of knee OA remains uncertain. While many studies focused on the detrimental effect of the chemical mediators released by IPFP and their role in the accentuation of the development of OA, only few studies elucidated the beneficial effect of IPFP maximal area as a local shock absorber protecting the adjacent articular structures from progressive damage. The aim of this study was to evaluate the relation between the IPFP maximal area and the prevalence of OA manifestations. We also studied the relation between the subcutaneous (SC) fat thicknesses on the medial aspect of the knee as a surrogate marker of body obesity and the IPFP area. Results A total of 216 knee scans for 188 adult patients (64 males and 124 females) who met the inclusion criteria were examined. They were between 45 and 66 years (mean 52.5 years). The mean IPFP area for all patients was 6.9 cm2 (± 1.6 SD) (ranged from 4.5 to 11 cm2). After adjustment for potential confounders, there was a significant negative association between IPFP area and radiographic manifestations of OA (osteophites, joint space narrowing, and grade of OA) (P value P value Conclusion In our study, we found supportive evidence that IPFP maximal area is associated with fewer osteoarthritic knee changes and less cartilage damage, suggesting that it plays a protective role against the development and progression of OA. Further large-scale clinical studies are awaited to confirm the obtained results. Based on our findings, it would be recommended to avoid IPFP resection during surgery in order to maintain its protective effect.

Radiologists tend to possess human error during pathologies scans for any abnormalities; thus, the introduction of automation shall has a great impact on accurately detecting injuries and more musculoskeletal examinations. Magnetic Resonance Imaging (MRI) scans are an effective method to detect injured sections but the process tends to be time-consuming and prone to human error. Therefore, our paper highlights the automation impact on knee MRI for abnormal, anterior cruciate ligament (ACL), meniscal damages using deep learning. Deep learning model such as Convolutional Neural Network (CNN) can infer the representation of images due to its properties: local connection and shared weights. We have explored two deep CNN models (VGG16 and VGG19) with transfer learning approach to predict knee injury on MRNet dataset collected by Stanford University. The classification accuracy obtained for abnormal, ACL tear, and meniscal tear are 83.19%, 84.96%, and 70.80%, respectively, using VGG16, whereas 84.07%, 84.96%, and 74.34%, respectively, using VGG19 model.

Background This work was conducted to assess the diagnostic efficiency of isotropic three-dimensional VISTA-fast spin echo versus standard two-dimensional fast spin echo at 1.5 T MRI, in the assessment of internal knee derangement in symptomatic patients, aiming to obtain similar diagnostic accuracy in a shorter time span, with reduction of partial volume artifacts by thin continuous sections. Results This was a non-randomized control study including 39 patients (32 male and 7 females, mean age 37 years old). A correlative study was done utilizing MRI standard 2D FSE (protocol A) versus 3D-VISTA-FSE (protocol B) for medial meniscus (MM) and lateral meniscus (LM), as well as anterior cruciate ligament ACL lesions, comparing the MRI results with the findings of arthroscopy as the gold standard. Both protocols depicted medial meniscus lesions with accuracy, specificity, and sensitivity (97.44%, 96.30%, and 100% respectively), lateral meniscus lesions with accuracy, specificity, and sensitivity (97.44%, 100%, and 50% respectively), and ACL lesions with accuracy, specificity, and sensitivity (100%, 100%, and 100% respectively), while there were no PCL lesions depicted through the study population. Comparing the time factor between both protocols revealed protocol A to consume 13.7 min, while protocol B consumed 6.6 min. Conclusion Three-dimensional isotropic VISTA-FSE sequence, although having similar accuracy in diagnosing cruciate and meniscal lesions as the standard sequences, facilitates thin-section data acquisition and multi-planar image reformation in standard and non-standard planes, without intersection gaps that are crucial for the detection and dissection of compound structures; also, it allows a shorter time span, which is more advantageous for patients, particularly the traumatized and emergency patients.

Background Simultaneous injury of two or more knee ligaments with concurrent tears involving the anterior cruciate and medial collateral ligaments is considered to be associated with femorotibial knee dislocations (KD). The purpose of this study is to characterize multiligamentous knee injury patterns associated with dislocations on MRI and to describe the incidence of their sequelae such as tibial plateau fractures, peroneal nerve injuries, and posterolateral corner (PLC) injuries. Participants and methods After obtaining institutional ethical committee approval, we retrospectively identified 108 multiligamentous knee injuries in 100 patients who met with trauma and were treated at our tertiary care center between April 2014 and December 2018. Descriptive statistics were reported using numbers and percentages for categorical variables in cases of multiligamentous injuries, ipsilateral tibial plateau fractures, ipsilateral femoral fractures, peroneal nerve injury, arterial injury, compartment syndrome, and PLC injuries. Results The most common (39.8%) injury pattern was a combined disruption of the anterior cruciate ligament, posterior cruciate ligament, and PLC. Schenck KD III-M was the most common injury type in KD, constituting 16.7%. Medial-sided injuries were the most common injury patterns seen with KD. There was a significant risk of peroneal nerve injury with lateral-sided injuries. Conclusion KD, though rare, may have devastating clinical sequelae such as compartment syndrome if not recognized and treated. Therefore, it is necessary to recognize imaging findings of femorotibial joint dislocations and associated injuries to the adjacent neurovascular bundles.

Pigmented villonodular synovitis (PVNS) is caused by a proliferation of the synovial membrane and can be a rare cause of pain and locking of the knee. In its localized form, it can be removed arthroscopically. We describe in detail a step-by-step arthroscopic technique applied to treat a 27-year-old patient who had been suffering from pain and episodes of locking for a year and whose left knee MRI revealed an intra-articular mass. The formation was completely enucleated arthroscopically and histological analyses confirmed the diagnosis of localized PVNS. There were no complications, and the patient was symptom-free at the six-month follow-up with no clinical or radiological evidence of recurrence.

The objective of our study was to evaluate the association between anterior tibial translation and injuries on the posterior horn medial meniscus (PHMM) and the integrity of the brake stop mechanism of the PHMM in the anterior cruciate ligament (ACL)-deficient knee.This retrospective study included 85 consecutive patients with an arthroscopically confirmed complete ACL tear. Anterior tibial translation was quantitatively measured using sagittal MRI at the midpoint of the lateral femoral condyle. The "uncovered medial meniscus" sign was considered positive if a vertical line tangent to the posteriormost margin of the medial tibial plateau intersected the PHMM at the midpoint of the medial femoral condyle on sagittal MRI. Concomitant injuries on the structures of the posteromedial and posterolateral corners of the knee, including PHMM tear and meniscal ramp lesion, were recorded. Stratified subgroup analysis and multivariable regression analysis were performed to identify factors associated with anterior tibial translation.The uncovered medial meniscus sign was positive in 21.2% (18/85) of patients and was significantly associated with anterior tibial translation. In the stratified subgroup analysis and multivariable regression analysis, positive uncovered medial meniscus sign consistently showed a significant association with anterior tibial translation and generated an additional 2.8 mm of anterior tibial translation. Other injuries, including PHMM tear and meniscal ramp lesion, were not associated with anterior tibial translation.The uncovered medial meniscus sign showed a statistically significant correlation with anterior tibial translation and could be a useful marker for the lost brake stop mechanism of PHMM in the ACL-deficient knee.

The studies of the relationship between anterior cruciate ligament (ACL) injury and notch size were in 2-D parameters in Han Chinese, the largest nation in the world, while few studies referred to the 3-D notch volume. The purpose of this study was to determine the differences in notch volume between individuals with and without ACL injuries and the optimal criterion value for abnormal notch volume and its sensitivity in predicting the risk of ACL injuries. Two hundred eighty individuals were included in this study, including 140 patients with non-contact sports ACL injuries only and 140 age- and gender-matched individuals without ACL injuries. Both groups underwent pre-operative knee MRI examinations and femoral notches were traced manually on 2-D MRI images, then 3-D notch volume was calculated. The notch volume was extremely smaller in the ACL-injured group than that in the control group (5.94 ± 1.35 versus 6.86 ± 1.61 cm3, P

To compare diagnostic performance of a 5-min knee MRI protocol to that of a standard knee MRI. One hundred 3 T (100 patients, mean 38.8 years) and 50 1.5 T (46 patients, mean 46.4 years) MRIs, consisting of 5 fast, 2D multi-planar fast-spin-echo (FSE) sequences and five standard multiplanar FSE sequences, from two academic centers (1/2015–1/2016), were retrospectively reviewed by four musculoskeletal radiologists. Agreement between fast and standard (interprotocol agreement) and between standard (intraprotocol agreement) readings for meniscal, ligamentous, chondral, and bone pathology was compared for interchangeability. Frequency of major findings, sensitivity, and specificity was also tested for each protocol. Interprotocol agreement using fast MRI was similar to intraprotocol agreement with standard MRI (83.0–99.5%), with no excess disagreement (≤ 1.2; 95% CI, −4.2 to 3.8%), across all structures. Frequency of major findings (1.1–22.4% across structures) on fast and standard MRI was not significantly different (p ≥ 0.215), except more ACL tears on fast MRI (p = 0.021) and more cartilage defects on standard MRI (p

The purpose of this study is to retrospectively investigate the frequency of a focal defect at the lateral patellar retinaculum on knee MRI and to determine the variables that are significantly associated with the defect.Two radiologists independently reviewed 99 knee MR images for the presence of a focal defect at the lateral patellar retinaculum and categorized patients with concordant results into two groups: a group with the defect (≥ 3 mm; group 1) and a group without the defect (3 mm; group 2). Clinical and radiologic variables, including the Kellgren-Lawrence radiographic grade, subcutaneous fat thickness, infrapatellar fat pad area, and the amount of joint effusion, were evaluated. The size and location of the defect were measured in group 1. To correlate MRI and histologic findings, MRI was performed for 11 cadavers, and three histologic specimens were obtained.Of the 99 knee MR images, concordant results between two reviewers were obtained for a total of 96 knees (97%): 25 knees (26%) in group 1 and 71 knees (74%) in group 2. A statistically significant difference between groups (p = 0.033) was noted for the infrapatellar fat pad area only. In all three cadaveric specimens, the lateral patellar retinaculum was more loose and sparse than the medial patellar retinaculum, and this site corresponded to the location of the defect on MRI.A focal defect of the lateral patellar retinaculum was not found to be a rare finding on knee MRI (frequency, 26%), and it may be a normal variant rather than a pathologic change. In addition, we suspect that a focal defect can be a route of infrapatellar fat herniation and a route of superficial extension of the infrapatellar fat pad lesion without a lateral patellar retinaculum tear or invasion.

The purpose of this study was to reveal the influence of the variance in width between the tibial spine and the femoral intercondylar notch on the occurrence of ACL injury. Thirty-nine subjects undergoing anatomical ACL reconstruction (30 female, 9 male; average age 29 ± 15.2) and 37 subjects with intact ACL (21 female, 16 male; average age 29 ± 12.5) were included in this study. In the anterior–posterior knee radiograph, tibial spine height, and the length between the top of the medial and lateral tibial spine (tibial spine width) were measured. In axial knee MRI exhibiting the longest femoral epicondylar length, intercondylar notch outlet length was measured and notch width index was calculated. Tibial spine width/notch outlet length, and tibial spine width/notch width index were compared between the ACL tear and intact groups. Tibial spine width/notch outlet length of the ACL tear and intact groups was 0.6 ± 0.1 and 0.7 ± 0.1, respectively. Tibial spine width/notch width index of the ACL tear and intact groups was 0.4 ± 0.1, and 0.6 ± 0.1, respectively. Both parameters were significantly larger in the ACL intact group. Both tibial spine width/notch outlet length and tibial spine width/notch width index were significantly smaller in the ACL tear group when compared with the ACL intact group. The occurrence of ACL injury influenced by the variance in width between the tibial spine and the femoral intercondylar notch. III.

Objective: Radiologists encounter bone marrow reconversion (BMR) frequently when evaluating knee magnetic resonance imaging (MRI). It is clinically important to know what these changes may be related to. The aim of this study to investigate the relationships between BMR at MRI with age, gender, body mass index (BMI), smoking and hemoglobin (hgb) levels in healthy adults. Methods: In this prospective study, 107 healthy adults aged 26-62 years (55 women, 52 men ) were evaluated with knee MRI. The participants were divided according to the smoking histories as two groups: nonsmokers and heavy smokers. Red bone marrow changes examined by a radiologist in coronal T1-weighted sequences and classified into four groups according to their sizes. The levels of blood hgb of all patients were acquired and BMIs’ were calculated. Statistical analyzes were performed with the SPSS 17.0 program. Results: 24 (54.55%) of 44 patients with BMR were nonsmokers and 20 (45.45%) were heavy smokers. No statistically relation was found between marrow BMR and smoking history (p>0,05). BMR was found to be more prevalent in obese female patients and over 41 years old patients (p0,05). Rekonversiyon, obez kadınlarda ve 41 yaş üzeri hastalarda istatiksel anlamlı olarak daha çok saptandı (p

Despite being one of the most common indications for surgery, data on the types of meniscus tear that should be treated surgically are limited. Improving patient selection requires agreement on meniscus tear description. This study evaluates a simple MRI tear classification system for inter-observer agreement. Knee MRI examinations from 57 subjects from the Osteoarthritis Initiative cohort were reviewed by two sub-specialty trained, musculoskeletal radiologists. Based on two pulse sequences, each meniscus was classified by: tear or no tear; location of tear in anterior, middle or posterior third or multiple thirds; and displaced or non-displaced radial, horizontal, longitudinal or complex tear pattern. A tear was defined as signal abnormality extending to the surface on at least two images and displacement as more than 2 mm of extrusion or separation measured orthogonal to the tear plane. Kappa, weighted Kappa and percentage agreement were calculated. For the medial meniscus, Kappa and percentage agreement estimates were, respectively: the presence of tear, 0.79 and 89.5%; tear with displacement, 0.70 (weighted Kappa) and 66.0%; tear description, 0.47 and 61.4%; tear location, 0.64 and 79.0%. For the lateral meniscus, estimates were: the presence of tear, 0.75 and 89.5%; tear with displacement, 0.81 (weighted Kappa) and 86.0%; tear description, 0.56 and 78.9%; tear location, 0.74 and 87.7%. The strength of agreement between readers was moderate to substantial underscoring the challenge of meniscus tear classification.

Purpose Quadriceps fat pad is located posterior to the quadriceps tendon. Increased signal intensity of this fat pad is seen on routine knee magnetic resonance imaging (MRI) examinations, but the exact mechanism and related pathologies are not clear. In this study we aimed to evaluate the relationship between MRI signal intensity and morphological features of quadriceps fat pad, as well as various pathologies of the patellofemoral joint. Material and methods Sixty-one knees with quadriceps fat pad oedema out of 457 knee MRI examinations were included. Quadriceps fat pad signal intensity, dimensions, posterior indentation, and various parameters related to patellofemoral joint such as trochlear facet asymmetry, trochlear depth and sulcus angle, and the Insall-Salvati ratio were evaluated. Results There was no statistically significant correlation between quadriceps fat pad oedema intensity and its dimensions, but it was significant when compared to posterior indentation. There was no correlation between fat pad oedema and each of the pathologies. However, there was a significant correlation between the presence of fat pad oedema and the presence of at least one of the pathologies related to patellofemoral joint. Conclusions Quadriceps fat pad oedema detected in MRI examinations should warn the radiologist against the presence of various pathologies related to the patellofemoral joint.

To describe the aspect of the anteromedial meniscofemoral ligament on MRI and to assess its prevalence.One thousand five hundred sixty knee MRI studies were retrospectively evaluated for the presence of an anteromedial meniscofemoral ligament. In addition to these studies, nine full MRI studies from our department's image archive were also analysed. The anteromedial meniscofemoral ligament length, thickness, and angle with respect to the tibial plateau were evaluated independently by two radiologists. For comparison purposes, the anterior cruciate ligament was assessed in the same manner.There was a 0.77% prevalence of the anteromedial meniscofemoral ligament in the study population. Compared to the anterior cruciate ligament, the anteromedial meniscofemoral ligament was 80.6%-83.8% thinner according to both observers (P = 0.0002), with a mean thickness of 1.53 ± 0.47 mm and 1.80 ± 0.66 mm determined by observers 1 and 2, respectively. The anteromedial meniscofemoral ligament angles were 15%-17.7% lower than the anterior cruciate ligament angles (P 0.003). Interobserver reproducibility was considered excellent for the length and angle measurements (ICCs varying from 0.85-0.97) and good for the thickness measurements (ICCs 0.66-0.77).The anteromedial meniscofemoral ligament is a rare structure that can be differentiated from the anterior cruciate ligament based on morphologic criteria.

Introduction MRI is the modality of choice for cartilage imaging, however, its diagnostic performance is variable. Objectives We aimed to evaluate whether deep learning can be utilized to accurately identify cartilage defects when applied to the interpretation of knee MRI images and compare deep learning's performance to that of an orthopaedic trainee and an orthopaedic surgeon. Methods We analyzed data from patients who underwent knee MRI evaluation and subsequent arthroscopic knee surgery (207 with-, 90 without cartilage defect). Patients' arthroscopic findings were compared to preoperative MRI images to verify the presence or absence of isolated tibiofemoral cartilage defects. For each patient, the most representative MRI image slice of the patient's condition was selected (defect or no-defect) from a coronal- and sagittal view. We developed three convolutional neural networks (CNNs) to analyze the images: CNN-1 trained on the images of the sagittal and coronal views; CNN-2 trained on the images of the sagittal view; CNN-3 trained on the images of the coronal view. We implemented image-specific saliency maps to visualize the CNNs decision-making process. The same test dataset images were then provided to an experienced orthopaedic surgeon and an orthopaedic trainee. Results Saliency maps demonstrated that the CNNs learned to focus on the clinically relevant areas of the MRI. The CNN-1 achieved higher performance (sensitivity-86.96, specificity-100%, positive predictive value [PPV]-100%, negative predictive value [NPV]-66.67%) than the orthopaedic surgeon (sensitivity-82.61%, specificity-83.33%, PPV- 95%, NPV-55.56%), Conclusions CNN can be used to enhance the diagnostic performance of MRI in identifying isolated tibiofemoral cartilage defects.

Background: There are clinical situations that radiology physicians need to assess Anterior Cruciate Ligament (ACL) and Posterior Cruciate Ligament (PCL) clearly with the two typical sequences (T2WI FSE sequence and Proton Density Fat Saturation) . However, a slight difference in using the applied sequences will result different levels of image quality information. The aim of this study is to compare clinical manifest in anatomical information on the resulted images between T2WI FSE sequence and Proton Density Fat Saturation and to define the best sequence that fit to reveal ACL and PCL of the knee joint.. Methods: The research was an experimental quasy. 20 sagital slices of the knee joint MRI were acquired from 10 volunteers who underwent MRI examinations with the two methods (T2WI FSE and Proton Density Fat Saturation). 3 experienced radiology physicians blended in the image scoring when review ACL and PCL appearances on knee MRI images. Inter-observer suitability was checked with Kappa test. A non-parametric Wilcoxon analyses was the statistical tool to test the null hypothesis. Results: The result showed a significant difference in anatomical information of ACL and PCL when T2WI FSE and Proton Density Fat Saturation sequences applied on the MRI of the knee joint sagital slices (p-value < 0,05). The mean rank of T2WI FSE was better than Proton Density Fat Saturation which contributed to the value at 4,50. There was an increase in signals that lead to ACL and PCL appear to be more hyper-intens compared to sorrounding organs in general, except the border line of PCL. By this means, it was useful for evaluating the patient whose particularly with ACL post-grafting. Conclusion: There was the difference in anatomical information between T2WI FSE sequence and Proton Density Fat Saturation on MRI knee joint with sagital slices for ACL and PCL studies. T2WI FSE sequence was the best method for showing anatomical information of ACL and PCL, although a relative low signal still occured from border line of PCL.

Trochlear dysplasia is a major risk factor for patellar instability. It has been sparsely reported that the trochlea can remodel when patellar stabilization is performed in skeletally immature patients before the age of 10 years. It is not known whether trochlea can remodel significantly after the age of 10 years. The purpose of the study was to evaluate trochlear remodeling in skeletally immature patients after patellar stabilization surgery, with a focus on children older than 10 years of age. In a retrospective study, knee MRI of 21 patients who had undergone patellar stabilization surgery, were evaluated. Twenty of these 21 patients were older than 10 years of age at time of surgery. The measurements of cartilaginous and bony sulcus angles, trochlear depth, and cartilaginous trochlear bump were compared between preoperative and postoperative MRI, using paired t-tests. In 20 patients older than 10 years of age, the mean cartilaginous sulcus angle change between preoperative and postoperative axial MRI was not significant (2.2°±7.9°, P=0.6). The mean change in the bony sulcus angle value was not significant (3.6°±6.8°, P=0.07). Similarly, there was no significant change in trochlear depth (P=0.8), or size of the trochlear bump (P=0.1). For one patient under 10 years of age at the time of surgery, there was a 21° and a 15° improvement in cartilaginous and bony sulcus angle, respectively. There were no significant changes in the trochlear parameters and trochlear remodeling in patients older than 10 years of age. Patellar stabilization at a younger age (

Background: The aim of this study was to deliver standardised terminology for the identification and stratification of patients with meniscal lesions of the knee. Methods: A national group of expert surgeons was convened by the British Association for Surgery of the Knee (BASK) and a formal consensus process was undertaken following a validated methodology. A combination of nominal group techniques and an iterative Delphi process was used to develop and refine relevant definitions. Where appropriate, definitions were placed into categories to facilitate use in clinical practice and guideline development. Results: A degenerative meniscus develops progressively with degradation of meniscal tissue and this may be revealed by intra-meniscal high signal on magnetic resonance imaging (MRI). A meniscal tear was defined as a defect or split in the meniscocapsular complex, which can occur in a degenerative or non-degenerative meniscus. Degenerative meniscal lesions (high signal or tear) are frequent in the general population and are often incidental findings on knee MRI. Symptoms were defined and classified into three groups: (1) strongly suggestive of a treatable meniscal lesion, (2) potentially suggestive of a treatable meniscal lesion, (3) osteoarthritic. A strategy for radiological imaging (radiograph ± MRI) was agreed for the investigation of the patients with a possible meniscal tear. Meniscal lesions and tear patterns on MRI imaging were defined and classified with reference to potential treatability: (1) target, (2) possible target, (3) no target. Conclusions: The agreed terminology will enable patients with meniscal lesions to be identified and stratified consistently in clinical practice, research and guideline development.

Background Timing of acquisition of post-contrast MR images for the assessment of the synovial membrane is important: delayed acquisition can result in contrast washout into synovial fluid.1 Several authors demonstrated the importance of this timing using qualitative data (membrane appearance on MRI).1–4 Nonetheless, there is no international consensus on timing of post-contrast images in arthritis, leading to acquisitions at 1 to 10 min after contrast injection.1 5 This could result in incorrect measurement of synovial thickness and thus imprecise assessment of disease activity and over or under treatment of patients. Objectives To quantitatively measure and compare thickness of the synovial membrane on early and late post-contrast knee MRI in patients with juvenile idiopathic arthritis (JIA). Methods Prospectively collected dynamic contrast-enhanced T1 MRIs of children with JIA were used to measure synovial thickness at time point 1 (TP1), 1 min and TP2, 5 min after contrast administration. Written and verbal informed consent for participation in our IRB-approved study was obtained. Two experienced readers, who were blinded for the time point, independently measured synovial thickness on a predefined, marked location in the patellofemoral compartment on randomised images. The Wilcoxon test was used to compare the mean synovial thickness measurements from TP1 and TP2. Moreover, we studied the number of patients judged to have active synovial inflammation (synovium >2 mm) on both time points. Results Measured synovial thickness in 53 patients with JIA (median age 13.5 years, 58.6% female) increased with prolonged time-after-contrast (TP1 1.4 mm and TP2 1.5 mm, p 2 mm) when comparing the measurements at TP2 versus TP1. Conclusions Our study is the first to add quantitative data to the literature showing that synovial thickness as measured on post-contrast MRI increases with a prolonged interval between contrast administration and acquisition of the post-contrast images. Our data, together with previous studies1 3 4 indicate that it is questionable whether one can reliably measure synovial thickness without standardisation of the interval between contrast administration and acquisition of post-contrast sequences. This could not only influence clinical interpretation and quantitative scoring in JIA, but possibly also impacts other rheumatologic diseases in which synovial thickness is quantified in scoring systems, such as rheumatoid arthritis and osteoarthritis.6 7 References [1] Ostergaard, et al. ARD2001;60:1050–1054. [2] Kursunoglu, et al. Radiology1990;176(3):831–835. [3] Yamato, et al. J CAT1993;17(5):781–785. [4] Rieter, et al. Pediatr Radiol2016;46(11):1562–1567. [5] Johnson, et al. Clin Radiol2002;57(6):466–471. [6] Ostergaard, et al. J Rheumatol2003;30:1385–1386.1. [7] Guermazi, et al. Ann Rheum Dis2011;70(5):805–811. Disclosure of Interest None declared

Segmentation of cartilage in knee MRI is an important process for various clinical tasks in diagnosis and treatment planning of osteoarthritis. Recently, the deep segmentation networks (DSNs) have been applied to the cartilage segmentation and have shown promising results. However, the DSNs have limitations for cartilage segmentation in that the networks tend to ignore smaller objects like the cartilage during learning the multi-class segmentation. In this paper, we propose a novel method for DSN-based cartilage segmentation using bone-cartilage-complex (BCC) modeling and bone-BCC-difference (BCD) extraction. To overcome the small cartilage ignorance of DSNs, we propose to construct the BCC which combines bone and cartilage in a single mask. Then we convert the problem of segmenting cartilages into the problem of segmenting the BCCs and bones, and extracting the cartilages by subtracting the bones from the BCCs. In addition, we apply 2.5D segmentation to further improve the segmentation accuracy by averaging the multiple segmentation masks on different planes with majority voting. In experiments, our BCD-Net achieved the average DSCs of 98.1% and 83.8% for femoral and tibial cartilages, respectively, and showed state-of-the-art-level performances in SKI10 public challenge validation dataset.

To evaluate the prevalence, clinical relevance, and magnetic resonance imaging (MRI) features of extra-capsular ganglia at the gastrocnemius origin and to assess their association with internal derangement and osteoarthritis of the knee.One hundred consecutive knee MRI examinations, obtained within a 6-month period from patients with no history of recent knee trauma, recent injections, inflammatory arthritis, infection, or tumours, were evaluated retrospectively for the presence of ganglia at the gastrocnemius origin. The lesions were divided into two groups: an intra-capsular and an extra-capsular group. Cyst morphology (size, shape, and internal septa), internal derangement of the knee (cartilage lesion, cruciate ligament injury, meniscal tear, and corner injury on MRI, and osteoarthritis of the knee on radiographs) were evaluated. The chi-square, Fisher's exact, and t-tests were used to compare the two groups, in addition to multivariate stepwise logistic regression analysis.Thirty-nine ganglia with an extra-capsular location were identified on 100 knee MRI (39 %). Rounded shape and internal septa were more common in the extra-capsular than in the intra-capsular group (p0.001). Frequencies of high-grade cartilage, meniscal tear, and high-grade osteoarthritis significantly differed between the groups (p≤0.038). In multivariate analysis, the only significant association was between high-grade osteoarthritis and the extra-capsular group.Extra-capsular ganglia at the gastrocnemius origin were not uncommon on knee MRI and had features typical of ganglia found at other sites. High-grade osteoarthritis was significantly associated with extra-capsular ganglia.

A ressonância magnética (RM), através de sua capacidade de caracterizar partes moles de forma não invasiva, tornou-se excelente método na avaliação da cartilagem. O desenvolvimento de novos e mais rápidos métodos possibilitaram aumento da resolução e do contraste na avaliação da estrutura condral, com maior precisão diagnóstica. Além disso, foram desenvolvidas técnicas fisiológicas de avaliação da cartilagem, capazes de detectar alterações precoces, antes do aparecimento das fissuras e erosões. Neste artigo de atualização serão discutidas e demonstradas as diversas técnicas de avaliação condral pela RM no joelho. Magnetic resonance imaging (MRI), through its ability to characterize soft tissue noninvasively, has become an excellent method in the evaluation of cartilage. The development of new and faster methods allowed increased resolution and contrast in the evaluation of chondral structure, with greater diagnostic accuracy. In addition, techniques were developed physiological assessment of cartilage which can detect early changes before the appearance of cracks and erosions. In this updated article will be discussed and demonstrated various techniques for assessing chondral knee by MRI.

Segmentation of the anterior cruciate ligament (ACL) in knee MRI remains a challenging task due to its inhomogeneous signal intensity and low contrast with surrounding soft tissues. In this paper, we propose a multi-atlas-based segmentation of the ACL in knee MRI with locally-aligned probabilistic atlas (PA) in an iterative graph cuts framework. First, a novel PA generation method is proposed with global and local multi-atlas alignment by means of rigid registration. Second, with the generated PA, segmentation of the ACL is performed by maximum-aposteriori (MAP) estimation and then by graph cuts. Third, refinement of ACL segmentation is performed by improving shape prior through mask-based PA generation and iterative graph cuts. Experiments were performed with a Dice similarity coefficients of 75.0%, an average surface distance of 1.7 pixels, and a root mean squared distance of 2.7 pixels, which increased accuracy by 12.8%, 22.7%, and 22.9%, respectively, from the graph cuts with patient-specific shape constraints.

Medial patellofemoral ligament (MPFL) reconstruction is a relatively new surgical technique for the treatment of recurrent patellar instability and dislocation. Radiologic findings following MPFL reconstruction are not well described in the existing literature. Here, we review the anatomy and biomechanics of the MPFL, review imaging findings following double-bundle MPFL reconstruction, and show examples of complications arising from reconstruction.

To compare magnetic resonance imaging (MRI) characteristics of torn and untorn post-operative menisci. The study group consisted of 140 patients with 148 partially resected menisci who were evaluated with a repeat knee MRI examination and subsequent repeat arthroscopic knee surgery. Two musculoskeletal radiologists retrospectively assessed the following MRI characteristics of the post-operative meniscus: contour (smooth or irregular), T2 line through the meniscus (no line, intermediate signal line, intermediate-to-high signal line, and high fluid-like signal line), displaced meniscus fragment, and change in signal pattern through the meniscus compared with baseline MRI. Positive predictive values (PPV) and negative predictive values (NPV) were calculated using arthroscopy as the reference standard. All 36 post-operative menisci with no T2 line were untorn at surgery (100% NPV), whereas 46 of the 79 post-operative menisci with intermediate T2 line, 16 of the 18 post-operative menisci with intermediate-to-high T2 line, and 14 of the 15 post-operative menisci with high T2 line were torn at surgery (58.2%, 88.9%, and 93.3% PPV respectively). Additional MRI characteristics associated with torn post-operative meniscus at surgery were irregular meniscus contour (PPV 85.7%), displaced meniscus fragment (PPV 100%), and change in signal pattern through the meniscus (PPV 99.4%). Post-operative menisci with no T2 signal line were untorn at surgery. The most useful MRI characteristics for predicting torn post-operative menisci at surgery were change in signal pattern through the meniscus compared with baseline MRI, and displaced meniscus fragment followed by high T2 line through the meniscus, intermediate-to-high T2 line through the meniscus, and irregular meniscus contour.

To compare multi-point Dixon magnetic resonance imaging (MRI) and fast spin-echo (FSE) T2-weighted imaging (WI) with regard to the size of metallic artefacts when imaging the knee joint.A total of 42 patients who underwent anterior cruciate ligament (ACL) reconstruction and follow-up imaging with 3 T MRI using the multi-point Dixon technique was included in this retrospective study. The maximal distance of the image distortion area around the metallic artefact was measured (interference screw of femoral tunnel area) on sagittal images of both FSE T2WI (T2WI and fat-suppressed [FS] T2WI) and multi-point Dixon (water only image and in-phase image) sequences. The maximal distance of the image distortion were compared using paired t-tests across the image sequences (multi-point Dixon water only image versus FS T2WI and multi-point Dixon in-phase image versus T2WI).The mean distance of the image distortion from metallic artefacts regardless of the image sequence ranged from 16.6 mm to 24.5 mm (Table 2). The mean distances measured by two readers on multi-point Dixon (water only image) sequences were significantly shorter than those in FS T2WI sequences (p0.001). In contrast, the mean distances measured by two readers on multi-point Dixon (in-phase image) sequences did not differ from those of T2WI (p0.05) sequences.The water-only image of multi-point Dixon technique reduces the amount of metallic artefacts compared to that in FS FSE T2WI sequences; however, the metallic artefacts were not significantly different between in-phase images of multi-point Dixon and FSE T2WI.

The use of Cartesian and Blade techniques also affects image quality. The Cartesian technique is more commonly used in Knee MRI examinations. Cartesian technique is vulnerable to movement, giving rise to motion artifacts. This motion artifact is often caused by too long scanning time, so ETL settings are important. An alternative to reducing this risk is to use the Blade technique and by setting the appropriate ETL. The research objective was to determine the differences image quality and anatomical information and to determine the technique that produced quality images and MRI anatomical information on the sagittal knee section between the Cartesian ETL and Blade T2 Weighted TSE combination. This is experiment research. Samples of 10 volunteers, carried out scanning with Cartesian and Blade techniques with variations ETL 14, 16, 18. Focus of assessment on ACL, PCL, meniscus, fluid, and fat. Image quality includes SNR and CNR. The assessment of the anatomical information by a radiologist. Data analyzed with Anova, Friedman, and Wilcoxon test. The results study showed that overall, there are significant differences in image quality between Cartesian and Blade techniques with p-value 0.005. There are differences in anatomical information with p-value

Purpose To investigate the accuracy of MRI in assessment of sports related knee injuries. Materials and methods From August 2012 to March 2013 thirty patients referred for sports related knee pain have been included in this study. Patients were subjected to a dedicated MR knee study and correlated knee arthroscopy and surgery. Results The study included thirty patients complaining of sports related knee pain, only 5 patients (16.6%) were with normal MRI findings and 25 patients (83.4%) were with abnormal MRI findings. Among the 25 patients who had injuries of their knees, 15 patients (60%) had ACL injuries, 2 patients (8%) had PCL injuries, 10 patients (40%) had meniscal injuries, 8 patients (32%) had collateral ligament injuries, 5 patients (20%) had bone injuries and 2 patients (8%) had muscular injuries. Only 7 patients (28%) were represented with isolated injury and 18 patients (72%) were represented with combined injuries. In correlation with arthroscopies and surgeries, morphological analysis was true-positive in 23 (92%) patients of the 25 injured patients, and true-negative in 3 (60%) patients of the 5 normal patients. Morphological analysis revealed overall 92% sensitivity and 60% specificity. Regarding the 15 patients who had ACL injuries, 13 patients (86.6%) were true-positive and 8 patients (80%) of the 10 patients who had meniscal injuries were true-positive. Conclusion MRI represents the optimal imaging tool in the evaluation of the sports related knee injuries, which has been shown to be an accurate and non invasive method of diagnosing ligament, meniscal, cartilage and muscular knee injuries.

The purpose of this study was to characterize meniscal ossicles and their association with meniscal root tears.A two-center retrospective assessment of 65 knee MRI studies with meniscal ossicles was performed. The relationship of the ossicle to the meniscal root and horn was assessed along with other findings of internal derangement of the knee.Meniscal ossicles were identified in patients ranging from 23 to 80 years old. The ossicles were located within the posterior horn and root of the medial meniscus in 57 of 65 (88%) examinations. Associated meniscal tears were seen at the site or adjacent to the ossicle in all but one examination (98%). Meniscal extrusion was present in 52% (34/65) of examinations. Associated findings included articular cartilage loss, which was severe in 51% (33/65) of examinations. Anterior cruciate ligament injury or prior anterior cruciate ligament reconstruction surgery was also identified in 58% (38/65) of examinations.Our findings show that the vast majority of meniscal ossicles are associated with posterior horn or meniscal root tears and a high incidence of focal articular cartilage loss as well as anterior cruciate ligament tears.

Objectives: Bone Marrow Lesions (BML) are a common finding on knee MRI. In the knee, BML have a strong correlation to patient-reported pain, function, joint deterioration and rapid progression to TKR. Histologic analyses of BML have demonstrated findings consistent with fracture and bony remodeling of the trabeculae. The Subchondroplasty (SCP®) Procedure aims to treat the bone defects present in the BML by percutaneously filling them with a bone substitute material, designed to flow through intact bone, harden at body temperature and then heal through natural bone turnover. Previous retrospective, single-center case series have demonstrated improvements in patient-reported outcomes. The purpose of this prospective, multi-center study is to evaluate the 2-year clinical and radiographic outcomes of patients with BML of the knee treated with the Subchondroplasty Procedure. Methods: Seventy patients were treated between 2012 and 2017 for BML of the tibial plateau and/or femoral condyle. Self-drilling cannulas were inserted into the BML using arthroscopic and fluoroscopic guidance, then injected with AccuFill® Bone Substitute Material. All patients also underwent arthroscopy to aid in targeting the underlying bony lesion and address intra-articular pathology. MRIs and radiographs were obtained pre-operatively, at 6, 12 and 24 months, with additional radiographs collected at 6 weeks and 3 months. Patient-reported outcomes, including VAS pain, IKDC and KOOS were collected pre-operatively, 2 and 6 weeks, and 3, 6, 12 and 24 months post-operatively. Results: Seventy patients (36 males and 34 females), average age 57 were consented and enrolled in the study. Preoperative K-L grade included 1.4% Grade 0, 2.9% Grade 1, 27.1% Grade 2, 55.7% Grade 3 and 7.1% Grade 4. Fifty eight tibial plateaus and 41 femoral condyles were treated (29 bipolar lesions treated). VAS Pain scores improved from a mean of 6.2/10 pre-op to 2.9/10 at 1 year. IKDC scores improved from mean 33.9 pre-op to 61.3 at 1 year. KOOS scores improved from baseline to 1 year (Fig. 1) with mean KOOS Pain from 45.8 to 73.9, ADL 52.9 to 79.2, Symptoms 49.7 to 71.9, Sports 21.2 to 49.9 and Quality of Life 18.1 to 52.3. All patient-reported outcomes showed statistically significant improvement at one year. Two year outcomes collected to date appear to follow the same trend. The last study subject is due to return in January 2019 at which point the final 2 year analysis will be completed. Six patients (8.6%) converted to arthroplasty (1 UKA and 5 TKA) at one year. To date, the 24 month conversion rate is 16.1% out of 62 subjects. The final conversion rate for 24 months will be calculated after the final subject returns. Radiographs and MRIs demonstrated good incorporation of the AccuFill material through 12 months with evidence of early remodeling and a lack of OA progression in the majority of subjects. Twenty-four month MRIs demonstrate continued remodeling of the AccuFill material. Conclusion: This study presents statistically and clinically-meaningful evidence of improvements in clinical outcomes following Subchondroplasty procedure for BML of the knee. The low conversion rate suggests this less-invasive procedure may delay the need for knee arthroplasty. MR imaging demonstrates good incorporation of the BSM and evidence of remodeling and reduction in material volume over time. [Figure: see text][Table: see text]

This study investigates whether measures of knee cartilage thickness can predict future loss of knee cartilage. A slow and a rapid progressor group was determined using longitudinal data, and anatomically aligned cartilage thickness maps were extracted from MRI at baseline. A novel machine learning framework was then trained using these maps. Compared to measures of mean cartilage plate thickness, group separation was increased by focusing on local cartilage differences. This result is central for clinical trials where inclusion of rapid progressors may help reduce the period needed to study effects of new disease-modifying drugs for osteoarthritis.

Background. Complete rupture of the anterior cruciate ligament (ACL) does not represent a diagnostic problem for the standard magnetic resonance (MR) protocol of the knee. Lower accuracy of the standard MR protocol for partial rupture of the ACL can be improved by using additional, dedicated MR techniques. The study goal was to draw a comparison between sagittal-oblique MR technique of ACL imaging versus flexion MR technique of ACL imaging and, versus ACL imaging obtained with standard MR protocol of the knee. Patients and methods. In this prospective study we included 149 patients who were referred to magnetic resonance imaging (MRI) examination due to knee soft tissues trauma during 12 months period. MRI signs of ACL trauma, especially detection of partial tears, number of slices per technique showing the whole ACL, duration of applied additional protocols, and reproducibility of examination were analysed. Results. Accuracy of standard MRI protocol of the knee comparing to both additional techniques is identical in detection of a complete ACL rupture. Presentations of the partial ruptures of ACL using flexion technique and sagittaloblique technique were more sensitive (p 0.65). Sagittal-oblique technique provides a higher number of MRI slices showing the whole course of the ACL and requires a shorter scan time compared to flexion technique (p Conclusions. Both additional techniques (flexion and sagittal-oblique) are just as precise as the standard MR protocol for the evaluation of a complete rupture of the ACL, so they should be used in cases of suspicion of partial rupture of the ACL. Our study showed sagittal-oblique technique was superior, because it did not depend on patient’s ability to exactly repeat the same external rotation if standard MR protocol was used or to repeat exactly the same flexion in flexion MR technique in further MR examinations. Sagittal-oblique technique does not require the patient’s knee to be repositioned, which makes this technique faster. We propose this technique in addition to the standard MR protocol for detection of partial ACL tears.

Background: Various studies have investigated structural knee changes after running, with conflicting results. Purpose: To perform a systematic review of acute changes in knee structures as detected by magnetic resonance imaging (MRI) after running and assess the reversibility of these changes. Study Design: Systematic review. Methods: A systematic literature search in Medline, Cochrane, Embase, and Scopus was performed. Articles that fulfilled predefined inclusion criteria were included and systematically reviewed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. Results: A total of 19 studies were included in this review. All studies performed standard knee MRI; 6 studies additionally performed T1ρ and T2 mapping. Sixteen studies assessed cartilage or meniscal morphological changes. Ten found no significant morphological changes after running. Six studies showed significant changes at the first follow-up. Six performed a second follow-up. Five showed no change compared with baseline and the first follow-up, and 1 showed a significant recovery compared with the first follow-up and no significant difference compared with baseline. Five of the 6 studies performing T1ρ and T2 mapping found significant changes in T2 and T1ρ values at the first follow-up. Three performed a second follow-up. Two found a significant recovery of T2 but no recovery of T1ρ. One study did not find a significant change compared with baseline. Ten studies assessed the patellar tendon, ligaments, synovial fluid, or subchondral bone. Changes at the first follow-up were not significant. A second follow-up was performed in 5 studies. All studies discovered recovery from the first follow-up. Conclusion: These data suggest that healthy athletes who have no risk factors for degenerative joint disease may present fleeting quantitative alterations after running. No irreversible, qualitative harmful effects seemed to occur, with the exception of persistent T1ρ elevation representing a proteoglycan depletion. Whether T1ρ changes need more than 3 months to recover or represent permanent structural damage remains to be investigated.