Central hole tear of the discoid meniscus of the knee in magnetic resonance imaging: mimicking the bucket-handle tear

Fusion of CNN1 and CNN2-based magnetic resonance image diagnosis of knee meniscus injury and a comparative analysis with computed tomography

PURPOSE

We used convolutional neural network (CNN) technology to improve the accuracy of diagnosis of knee meniscus injury and shorten the diagnosis time.

METHOD

We propose a meniscus detection method based on Fusion of CNN1 and CNN2 (CNNf), which uses Magnetic Resonance Imaging (MRI) and Computer tomography (CT) to compare the diagnosis results, verifies the proposed method through 2460 images collected from 205 patients in the hospital. We used accuracy, sensitivity, specificity, receiver operating characteristics (ROC), and damage total rate to evaluate performance.

RESULTS

The accuracy of our model was 93.86%, the sensitivity was 91.35%, the specificity was 94.65%, and the area under the receiver operating characteristic curve was 96.78%. The total damage rate of MRI is 91.57%, which is far greater than the total damage rate of CT diagnosis of 80.13%.

CONCLUSION

CNNf-based MRI technology of knee meniscus injury has high practical value in clinical practice. It can effectively improve the accuracy of diagnosis and reduce the rate of misdiagnosis.

Demographics and Epidemiology of Discoid Menisci of the Knee: Analysis of a Large Regional Insurance Database

Background:

A discoid meniscus is a morphological variant of normal knee joint meniscus shape and ultrastructure that can lead to traumatic tearing of this tissue and early joint osteoarthritis.

Purpose/Hypothesis:

The purpose of this study was to determine the prevalence of discoid menisci in a large, ethnically diverse regional cohort and to evaluate possible risk factors. The hypothesis was that there would be no difference in the epidemiological distribution of discoid menisci based on ethnicity or sex.

Study Design:

Descriptive epidemiology study.

Methods:

The study population was from a regional, integrated health care system cohort from Kaiser Permanente of Southern California that, as of 2016, included more than 4.5 million patients. Patient demographics included age, sex, and ethnicity within this cohort. Potential risk factors analyzed included age, sex, ethnicity, and body mass index (BMI). Unique characteristics of a discoid meniscus were analyzed, including a symptomatic versus asymptomatic meniscus, location of meniscal tear and type of meniscus, and frequency of meniscal surgical treatment.

Results:

A total of 223 patients with a confirmed discoid meniscus were identified, yielding an overall prevalence rate of 4.88 per 100,000 patients. Those identifying as Black had the lowest prevalence (2.68/100,000), while Hispanic ethnicity had the highest (6.01/100,000). However, there was no significant difference with regard to ethnicity (P = .283), nor any significant difference between sexes. BMI did not significantly influence the rate of discoid menisci (P = .504). A majority (77.5%) of patients were symptomatic, while 22.5% of patients with discoid menisci were asymptomatic and discovered incidentally. Symptomatic discoid menisci were more likely to be operated on compared with asymptomatic discoid menisci (71% vs 14%, respectively; P = .001; odds ratio, 14.8 [95% CI, 5.8-37.2]). Horizontal and bucket-handle tears were the more common tear types. Of the discoid menisci in this cohort, 55.6% underwent surgery, with 95.2% undergoing reported saucerization.

Conclusion:

In this very diverse population-based cohort of patients, there did not seem to be a significant predilection of discoid menisci with regard to ethnicity. Neither sex nor BMI significantly influenced the rate of discoid menisci. More than three-quarters of those with a diagnosed discoid meniscus were symptomatic. Of the tears that occurred with discoid menisci, horizontal and bucket-handle tears made up the largest proportion.

Anteromedial Meniscofemoral Ligament of the Anterior Horn of the Medial Meniscus: Clinical, Magnetic Resonance Imaging, and Arthroscopic Features

PURPOSE

To describe the clinical, arthroscopic, and magnetic resonance imaging (MRI) findings of knees with anomalous insertion of the anterior horn of the medial meniscus (AHMM) into the intercondylar notch via an anteromedial meniscofemoral ligament (AMMFL).

METHODS

A total of 2,503 arthroscopic knee surgeries performed from July 2003 to October 2016 were reviewed retrospectively to identify knees with an AMMFL. Medical records, arthroscopic photographs, and MRI of identified cases were analyzed. Meniscus width and extrusion were measured on MRI. Fifty patients with a normal meniscus were selected as a control group.

RESULTS

A total of 13 (0.52%) patients had an AMMFL with insertion at the intercondylar notch. All cases were diagnosed incidentally during arthroscopy. The characteristics of knee pain were related to surgical pathology. Arthroscopic examination revealed the AMMFL as a band-like structure covering the anterior cruciate ligament. In all cases, the AHMM had no bony attachment to the tibia, and increased mobility was observed on probing of the AHMM. The medial meniscus (MM) was significantly larger than the general size in 8 cases (61.5%). Twelve knees (92.3%) had meniscus tears. On MRI, the AMMFL appeared as a low-signal linear structure arising at the AHMM and coursing superiorly along the anterior cruciate ligament. The mean MM width was greater than that in the control group at the mid-body (P = .030), anterior horn (P = .002), and posterior horn (P = .001).

CONCLUSIONS

All cases of AMMFL were found incidentally during arthroscopic surgery, and the AMMFL was a silent lesion. There was no significant meniscal extrusion, although the AHMM had no bony attachment. This is because the AMMFL may act as an anchor for the AHMM. Therefore, the AMMFL should not always be removed. The MM with an AMMFL tended to be larger than the typical MM and may be related to some degree of hypermobility, which raises the risk of meniscal tears.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

The clothes maketh the sign

Abstract

Pattern recognition is a key tool that enables radiologists to evoke certain diagnoses based on a radiologic appearance. In Shakespeare’s Hamlet, Polonius tells his son Laertes to dress well because “apparel oft proclaims the man”; this phrase is now expressed in modern parlance as “the clothes maketh the man”. Similarly in radiology, appearances are everything, and in the case of radiologic signs, occasionally “the clothes maketh the sign”. The radiologic signs described in this pictorial review resemble items of clothing, fabric types, headwear, or accessories and are found in the musculoskeletal, pulmonary, gastrointestinal, and genitourinary systems. These “clothing signs” serve as a useful visual trigger to help radiologists to identify particular disease entities.

Teaching Points

• Pattern recognition enables radiologists to evoke a diagnosis based on radiologic appearance.

• The radiologic signs described in this review resemble clothing, fabric, or accessories.

• These “clothing signs” serve as visual triggers that evoke particular disease entities.

An atypical symptomatic discoid lateral meniscus in a toddler

Meniscal tears and meniscal instability are rare complications of a discoid lateral meniscus in a very young child. We report a case of a 32-month-old male who presented with a limp and limited extension of his right knee. Magnetic resonance and sonographic images demonstrated a discoid meniscus with a posterior horn tear and unstable anterior horn, confirmed by arthroscopy. The patient was treated with saucerization of the lateral discoid meniscus, debridement of the posterior horn tear, and repair of the unstable anterior horn. This case shows a rare complication of variant anatomy that is not well documented in the pediatric radiologic literature, but nonetheless should be considered in the pediatric population.

Systematic review of the concurrent and predictive validity of MRI biomarkers in OA

OBJECTIVE

To summarize literature on the concurrent and predictive validity of MRI-based measures of osteoarthritis (OA) structural change.

METHODS

An online literature search was conducted of the OVID, EMBASE, CINAHL, PsychInfo and Cochrane databases of articles published up to the time of the search, April 2009. 1338 abstracts obtained with this search were preliminarily screened for relevance by two reviewers. Of these, 243 were selected for data extraction for this analysis on validity as well as separate reviews on discriminate validity and diagnostic performance. Of these 142 manuscripts included data pertinent to concurrent validity and 61 manuscripts for the predictive validity review. For this analysis we extracted data on criterion (concurrent and predictive) validity from both longitudinal and cross-sectional studies for all synovial joint tissues as it relates to MRI measurement in OA.

RESULTS

Concurrent validity of MRI in OA has been examined compared to symptoms, radiography, histology/pathology, arthroscopy, CT, and alignment. The relation of bone marrow lesions, synovitis and effusion to pain was moderate to strong. There was a weak or no relation of cartilage morphology or meniscal tears to pain. The relation of cartilage morphology to radiographic OA and radiographic joint space was inconsistent. There was a higher frequency of meniscal tears, synovitis and other features in persons with radiographic OA. The relation of cartilage to other constructs including histology and arthroscopy was stronger. Predictive validity of MRI in OA has been examined for ability to predict total knee replacement (TKR), change in symptoms, radiographic progression as well as MRI progression. Quantitative cartilage volume change and presence of cartilage defects or bone marrow lesions are potential predictors of TKR.

CONCLUSION

MRI has inherent strengths and unique advantages in its ability to visualize multiple individual tissue pathologies relating to pain and also predict clinical outcome. The complex disease of OA which involves an array of tissue abnormalities is best imaged using this imaging tool.

Ressonância magnética na avaliação das variações anatômicas meniscais e da anatomia ligamentar perimeniscal: potenciais causas de erro de interpretação

O conhecimento adequado das variações anatômicas meniscais e das estruturas perimeniscais é essencial para uma avaliação adequada dos exames de ressonância magnética do joelho, tanto no diagnóstico das lesões meniscais quanto para se evitar uma série de possíveis erros diagnósticos. Este artigo revê variações anatômicas que alteram o tamanho, a forma e a estabilidade meniscais e que incluem os vários tipos de menisco discoide, outras variações morfológicas meniscais menos frequentes e o ossículo meniscal. Também é revisada a anatomia de estruturas perimeniscais, principalmente ligamentares, que incluem os ligamentos meniscocapsulares, intermeniscais, meniscofemorais e extensões meniscoligamentares.

The anatomical basis for a novel classification of osteoarthritis and allied disorders

Osteoarthritis (OA) has historically been classified as 'primary' where no discernible cause was evident and 'secondary' where a triggering factor was apparent. Irrespective of the triggering events, late-stage OA is usually characterized by articular cartilage attrition and consequently the anatomical basis for disease has been viewed in terms of cartilage. However, the widespread application of magnetic resonance imaging in early OA has confirmed several different anatomical abnormalities within diseased joints. A key observation has been that several types of primary or idiopathic OA show ligament-related pathology at the time of clinical presentation, so these categories of disease are no longer idiopathic - at least from the anatomical perspective. There is also ample evidence for OA initiation in other structures including menisci and bones in addition to articular cartilage. Therefore, a new classification for OA is proposed, which is based on the anatomical sites of earliest discernible joint structural involvement. The major proposed subgroups within this classification are ligament-, cartilage-, bone-, meniscal- and synovial-related, in addition to disease that is mixed pattern or multifocal in origin. We show how such a structural classification for OA provides a useful reference framework for staging the magnitude of disease. For late-stage or end-stage/whole organ disease, the final common pathway of these different scenarios, joint replacement strategies are likely to remain the only viable option. However, for younger subjects in particular, near the time of clinical disease onset, this scheme has implications for therapy targeted to specific anatomical locations. Thus, in the same way that tumours can be classified and staged according to their tissue of origin and extent of involvement, OA can likewise be anatomically classified and staged. This has implications for therapeutic strategies including regenerative medicine therapy development.