MR imaging-based diagnosis and classification of meniscal tears

Reduced physiological extrusion of the medial meniscus in axial load-bearing condition in anterior cruciate ligament deficiency

PURPOSE

In this study, ultrasonography was used to measure medial meniscus (MM) extrusion under weight-bearing and nonweight-bearing conditions in both anterior cruciate ligament (ACL)-deficient and ACL-intact knee groups. This study aimed to determine the possible differences between these groups with an eventual impact on meniscal tears in ACL-deficient knees.

METHODS

A total of 107 patients who underwent ACL reconstructive surgery between June 2022 and April 2023 were enroled. After applying exclusion criteria, 37 patients met the conditions for inclusion in the study and formed the ACL deficiency group (Group D). Of the 141 patients presenting to an outpatient clinic who agreed to have ultrasonography conducted on their nondiscomforting contralateral knee, 37 patients matched for age, sex, hip-knee-ankle angle and body mass index with Group D patients were selected for the ACL intact group (Group I). Ultrasonography was used to measure MM extrusion in weight-bearing and nonweight-bearing conditions for all participants.

RESULTS

Seventy-four patients were included in the study (n = 37 per group). The supine position showed an MM extrusion of 1.2 ± 0.7 mm in Group I and 1.2 ± 0.7 mm in Group D (not significant). In the standing position, MM extrusion measured 2.0 ± 0.6 mm in Group I and 1.3 ± 0.8 mm in Group D. The difference in extrusion (Δextrusion) between the two positions was 0.8 ± 0.6 in Group I and 0.1 ± 0.2 in Group D, with statistical significance (p < 0.01). A consistent reduction in MM extrusion during weight-bearing was observed in patients with ACL deficiency, irrespective of the duration of ACL deficiency, age, sex and BMI.

CONCLUSION

ACL deficiency did not significantly impact MM extrusion during nonweight-bearing conditions; however, less MM extrusion was observed in response to axial loading conditions. These findings indicate altered MM biomechanics due to increased anterior-posterior meniscal motion and rotational instability after ACL injury.

LEVEL OF EVIDENCE

Level III.

Malignant Dendritic Cell Sarcomas in the Skin: 2 Cases of Rare Sarcoma Subtypes With Literature Review

ABSTRACT

Interdigitating dendritic cell sarcoma is a rare, aggressive hematological malignancy primarily originating in lymph nodes, with only 10 reported cases presenting in the skin (primary cutaneous interdigitating dendritic cell sarcoma). Past presentations showed erythematous nodules on the proximal extremities, back, or face. Morphologically, these neoplasms are similar to melanomas and other dendritic cell (DC) tumors, making their diagnosis difficult. Here, we present 1 case of primary cutaneous interdigitating dendritic cell sarcomas and another 1 of malignant indeterminate dendritic cell tumor (indeterminate DC sarcoma). The first case is an 83-year-old man who presented with recent ulceration and bleeding of an asymptomatic, slow growing lesion on his right thigh with biopsy revealing a large, well-circumscribed polypoid spindle cell tumor in the dermis with atypical cells with vesicular nuclei in a lymphoplasmacytic background and immunohistochemistry positivity for CD45, CD68, S100, and Cyclin D1. The second case is a 74-year-old man who presented with a progressively darkening and enlarging abdominal skin lesion with biopsy revealing a diffuse infiltrate of atypical poorly differentiated pleomorphic nuclear cells and immunohistochemistry positivity for S100, CD1a, CD56, CD43, cyclin D1, CD31, CD4, and BRAF V600E. Our findings contribute to expand the reported literature on primary cutaneous DC sarcomas.

Factors associated with medial meniscal extrusion in non-osteoarthritic knees with medial meniscus tears: A cross-sectional study

BACKGROUND

Medial meniscal extrusion (MME) plays an important role in the progression of knee osteoarthritis. Exploring the factors associated with MME in non-osteoarthritic knees may assist in the prevention of osteoarthritis.

OBJECTIVE

To identify the factors associated with pathologic MME in non-osteoarthritic knees with medial meniscus tears (MMTs).

DESIGN

A cross-sectional study.

PARTICIPANTS

One hundred fifty patients with non-osteoarthritic knees who underwent arthroscopic surgery for MMT. Patients were divided into a pathologic MME group (n = 54) and a control group (n = 96) based on whether a pathologic MME was present on magnetic resonance (MR) images.

SETTING

Tertiary medical institution.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The MME distance was measured on a coronal MR image obtained at the midpoint of the medial femoral condyle. An MME distance ≥3 mm was considered to indicate pathologic MME. Demographic and clinical data were collected as variables. Multivariable logistic regression analysis was performed to identify factors associated with pathologic MME.

RESULTS

After multivariable adjustment, body mass index (BMI) and the type of MMT were associated significantly with pathologic MME in the multivariable logistic regression model. Each unit higher in BMI was associated with a 13% higher risk of pathologic MME (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.01-1.28, p = .04). The odds of pathologic MME were approximately four times and three times higher for radial tears (OR 4.34, 95% CI 1.25-15.03, p = .02) and complex tears (OR 3.07, 95% CI 1.17-8.05, p = .02) than for horizontal and longitudinal tears.

CONCLUSIONS

BMI and the type of MMT were independent factors associated with pathologic MME in non-osteoarthritic knees with MMT. A higher BMI, radial tears, and complex tears were predisposed to pathologic MME.

Prevalence of Articular Surface Injuries in Patients Undergoing Meniscal Surgery: A Retrospective Analysis of 758 Cases

Background and aim Meniscal tears are often associated with articular surface damage, which could be an important factor in the clinical outcome. However, these concomitant lesions are usually reported as binary variables. Reports of the severity/extent of the concomitant lesions and stratification by meniscal tear are scarce in the literature; in addition, sample sizes of previous reports are limited. This study aimed to characterize meniscal lesions, determine the prevalence of articular surface lesions and their severity, and correlate these lesions with meniscal injury characteristics. Methods A cross-sectional study of patients undergoing meniscal surgery between 2017 and 2023 was conducted. Patient characteristics and arthroscopic findings on the location and type of meniscal injury as well as the degree of chondral lesion (sICRS score) were recorded by the surgeon. Statistical analysis included frequency reporting for patient characteristics and study variables, including the median and interquartile range of the sICRS classification of articular surface lesions. Meniscal tear types were categorized as degenerative or non-degenerative to explore associations with chondral injury. Chi-square test and univariate and multivariate logistic regression models were employed to analyze relationships between variables. Results A total of 758 surgeries were analyzed, with a mean age of 39.56 years (SD: 12.71) and 67.90% male participants. Medial meniscus injuries accounted for 57.52%, lateral meniscus 36.02%, and both menisci 6.64%. Significant differences were found in vascular area, topography, and lesion type between isolated medial and lateral meniscus lesions (p<0.01). Chondral lesions were present in 35.22% of cases, with significant differences among meniscal injury types (p<0.01). Degenerative tears showed higher rates of chondral damage compared to non-degenerative tears, particularly in lateral meniscus injuries (p<0.01). Regression analysis identified age, gender, meniscal injury characteristics, and meniscectomy percentage as risk factors for articular surface injuries. Conclusion Articular surface injuries frequently accompany meniscal lesions, with associations between affected menisci and articular damage extent. Femoral condyles show greater involvement corresponding to compartment-specific meniscal lesions, unlike tibial plateaus. Meniscal degeneration is present in about half of articular cartilage injury cases. Some meniscal tear types may relate to more severe articular lesions, but larger studies are needed to confirm these findings and explore other tear patterns.

Imaging of the Pediatric Knee

During normal development, imaging findings in the immature knee joint may mimic pathology or indicate transient sites of weakness, prone to injury. This article reviews the development of the knee joint, age- and maturation-dependent imaging considerations, and various developmental variants that can be encountered, subdivided into those that involve the tibiofemoral and patellofemoral compartments, soft tissues, and osseous components. The tibiofemoral compartment section reviews the focal periphyseal edema zone (FOPE), ossification variants of the femoral condyles, distal femoral metaphyseal cortical irregularity from periosteal traction, and the metaphyseal subperiosteal stripe, which should be distinguished from pathologic mimickers such as endochondral ossification dysfunction, osteochondritis dissecans (OCD), fibroosseous lesion, periosteal and subcortical pathologies. The patellofemoral compartment section includes a review of partite patella, dorsolateral defect, variant trochlear morphology, and maturation-dependent sites of transient weakness that are prone to injury from repetitive overuse (Sinding-Larsen-Johansson syndrome and Osgood-Schlatter disease) and avulsion fractures (patellar sleeve and tibial tubercle avulsions). Finally, soft tissue (discoid lateral meniscus, meniscal flounce, anterior cruciate ligament variants) and osseous components (meniscal ossicle, fabella, and cyamella) are reviewed.

Faster acquisition of magnetic resonance imaging sequences of the knee via deep learning reconstruction: a volunteer study

AIM

To evaluate whether deep learning reconstruction (DLR) can accelerate the acquisition of magnetic resonance imaging (MRI) sequences of the knee for clinical use.

MATERIALS AND METHODS

Using a 1.5-T MRI scanner, sagittal fat-suppressed T2-weighted imaging (fs-T2WI), coronal proton density-weighted imaging (PDWI), and coronal T1-weighted imaging (T1WI) were performed. DLR was applied to images with a number of signal averages (NSA) of 1 to obtain 1DLR images. Then 1NSA, 1DLR, and 4NSA images were compared subjectively, and by noise (standard deviation of intra-articular water or medial meniscus) and contrast-to-noise ratio between two anatomical structures or between an anatomical structure and intra-articular water.

RESULTS

Twenty-seven healthy volunteers (age: 40.6 ± 11.9 years) were enrolled. Three 1DLR image sequences were obtained within 200 s (approximately 12 minutes for 4NSA image). According to objective evaluations, PDWI 1DLR images showed the smallest noise and significantly higher contrast than 1NSA and 4NSA images. For fs-T2WI, smaller noise and higher contrast were observed in the order of 4NSA, 1DLR, and 1NSA images. According to the subjective analysis, structure visibility, image noise, and overall image quality were significantly better for PDWI 1DLR than 1NSA images; moreover, the visibility of the meniscus and bone, image noise, and overall image quality were significantly better for 1DLR than 4NSA images. Fs-T2WI and T1WI 1DLR images showed no difference between 1DLR and 4NSA images.

CONCLUSION

Compared to PDWI 4NSA images, PDWI 1DLR images were of higher quality, while the quality of fs-T2WI and T1WI 1DLR images was similar to that of 4NSA images.

Usefulness of platelet-rich fibrin as a scaffold for meniscal repair: A non-randomized controlled cohort/follow-up study

Background

Although regenerative medicine treatment is still in its infancy in Japan, legislation within the past decade has provided opportunities to explore new treatment methods using regenerative medicine. We conducted a 2-year prospective follow-up study to statistically analyze treatment outcomes using platelet-rich plasma (PRP) and platelet-rich fibrin (PRF) as effective scaffolds in meniscal repair.Questions/Purposes.1. Does the use of PRF and PRP for meniscal repair surgery regenerate the meniscus?2. Does augmentation of meniscal repair with PRF effectively improve knee function outcomes?

Methods

Thirty-five patients underwent arthroscopic meniscal repair with PRP and PRF using new devices with all-inside techniques. Among these, 31 patients were evaluated for clinical outcomes postoperatively, and magnetic resonance imaging (MRI) findings were evaluated. The variables were coded appropriately by creating a new column based on the Kellgren-Lawrence classification over time. Log transformation of different time points (pre, post 6, 12, or 24 months) in relation to Lysholm, International Knee Documentation Committee (IKDC), Japanese Orthopedic Association (JOA), and Tegner scores were performed. Follow-up arthroscopy using a needle scope was performed in some cases 2 years later. The PRP and PRF used were characterized using the Minimum Information for Studies Evaluating Biologics in Orthopaedics classification.

Results

Overall, 31 patients were evaluated (mean age = 39.1 ± 15.7 years; preoperative rehabilitation period = 9.5 ± 7.7 weeks). The PRP had mean platelet and white blood cell concentrations of approximately 5.5- and 3.6-fold, respectively. A significant association existed between sex and deformity deterioration but not in age between the two groups classified by deformity deterioration. Surgical intervention significantly and positively impacted knee function, although no significant changes were found in the activity of the participants over time. MRI findings showed no regeneration of the repaired meniscus; nevertheless, none of them worsened. Furthermore, a case where the traumatic cartilage defect was covered with fibrocartilage-like tissue as a secondary finding was observed.

Conclusions

Meniscal repair surgery using PRP/PRF is an effective treatment option for improving knee function in patients with knee deformity.

Level of evidence

Level III, Non-randomized controlled cohort/follow-up study.

Horizontal Cleavage Meniscus Tear: "The Quad Tendon Augmentation Technique"

The management of medial meniscus horizontal cleavage tears can be challenging. Currently, several treatment options, including nonoperative and surgical options, have been proposed in the literature. Different repair techniques aiming to promote the healing process have been reported and have shown good outcomes. However, recurrent parameniscal cysts and decreased meniscal volume have also been reported. In this Technical Note, a novel surgical technique to repair a horizontal cleavage tear of the posterior horn of the medial meniscus is reported in young patients. The technique uses a strip of autologous quadriceps tendon to fill the void between the upper and lower meniscal leaflets followed by an all-inside compression suture. Both of these technical features aim to overcome the limitations of current repair techniques.

Meniscal extrusion consensus statement: A collaborative survey within the Meniscus International Network (MenIN) Study Group

PURPOSE

The purpose of the present study was to perform a survey administered to members of the Meniscus International Network (MenIN) Study Group, seeking to delineate the most contentious aspects of meniscal extrusion classification and provide a foundation for new, more comprehensive definitions and treatments for these pathologies.

METHODS

MenIN Study Group is a group of international experts treating and performing research on meniscus pathology and treatment. All MenIN Study Group members were asked to complete a survey aimed at establishing criteria for the optimal classification system for meniscal extrusion. Data obtained from the completed questionnaires were transferred into a spreadsheet and then analysed. All responses are presented as counts, percentages or means.

RESULTS

Forty-seven (85.5%) MenIN Study Group members completed the survey and were included in this analysis. Key aspects recommended for inclusion in a comprehensive classification system for meniscal extrusion included laterality (93.6%), anatomical location (76.6%), patient age (76.6%), body mass index (BMI) (68.1%) and aetiology (68.1%). For classifying meniscal extrusion, 53.2% considered the distance in millimetres from the tibial plateau's outer margin as the most reliable measurement technique on imaging. Preferences for imaging modalities varied, with 44.7% favouring weight-bearing magnetic resonance imaging (MRI) and 36.2% opting for weight-bearing ultrasound due to its greater availability. Respondents advocated for a classification system addressing stability or progression of meniscal extrusion (66%), reducibility (53.2%), potential progression of knee osteoarthritis (OA) (83%), influencing treatment approaches (83%), a gradation system (83%), consideration of dynamic factors (66%), association with clinical outcomes and prognosis (76.6%) and investigation around centralization procedures (57.4%).

CONCLUSIONS

In conclusion, the findings of this survey shed light on the global perspectives regarding meniscal extrusion classification. It was generally felt that a new classification of extrusion measured on MRI scans at the mid-tibial plateau should be developed, which considers factors such as laterality, anatomical location, age, BMI and aetiology. Additionally, the results support the integration of dynamic factors and clinical outcomes in MRI-based classifications to inform treatment approaches.

LEVEL OF EVIDENCE

Level IV.

Three Morphological Risk Factors for Predicting Isolated Meniscal Bucket-handle Tear

Purpose

The study aimed to investigate whether morphometric variables of the knee can predict isolated meniscal bucket-handle tears and identify the risk factors.

Methods

The study included 146 participants with a mean age of 36.547 ± 12.279 years. They included two groups of 73 patients each: one group with isolated meniscal bucket-handle tears and another with no knee injury (control group). Magnetic resonance imaging findings of the participants were retrospectively assessed. A few morphometric variables associated with distal femur, proximal tibia, and cruciate ligaments were measured.

Results

Cruciate ligament tensity (CLT), medial femoral condylar height (MFCH), and lateral meniscal bone angle (LMBA) were found to be 12.7 ± 0.3, 30.1 ± 2.5 mm, and 21.2° ± 3.4°, respectively, in patients with meniscal bucket-handle tear, compared with 11.9 ± 0.2, 28.3 ± 2.7 mm, and 26.5° ± 3.7° in the control group, respectively. Based on multivariate Firth's logistic regression analysis, CLT (Odds ratio [OR]: 456.533; 95% confidence interval [CI]: 27.582 to > 999.999), MFCH (OR: 1.603; 95% CI: 1.023-2.513), and LMBA (OR: 0.780; 95% CI: 0.624-0.975) could distinguish between meniscal bucket-handle tears and knees without meniscus tears (p < 0.05). Based on the multicategorical multinominal regression model, CLT (OR: > 999.999; 95% CI: 49.937 to > 999.999) and MFCH (OR: 1.903; 95% CI: 1.005-3.606) were the determinant variables in differentiating medial meniscal bucket-handle tears from knees without meniscus tears (p < 0.05).

Conclusion

Large CLT, high medial condyle, and small LMBA were revealed as the morphometric risk factors for meniscal bucket-handle tear.

"Ring-shaped" meniscus and accompanying intermeniscal bridge meniscus: a rare combined variant resembling a bucket-handle tear

Many anatomical variations have been described in the menisci, especially in the lateral meniscus. Among these, discoid meniscus is the most common variation. Others are described in the literature as double-layered meniscus, accessory meniscus, ring-shaped meniscus, and hypoplastic meniscus. Also, combined variations associated with ring-shaped meniscus have been described, and they can be confused with fragmented complex tears and cause unnecessary surgery. Increasing awareness of the imaging features of these accompanying combined variations may aid in the recognition and differentiation of this entity from meniscus tears. We report the case of a ring-shaped meniscus and accompanying intermeniscal bridge meniscus, which has not been described before in the literature, highlighting the MRI and arthroscopic imaging findings of it.

Maturation-dependent patterns of knee injuries among symptomatic pediatric soccer players on MRI

OBJECTIVE

To systematically investigate the prevalence of knee MRI findings among symptomatic pediatric soccer players with respect to skeletal maturity and to identify predictors of surgery.

METHODS

This IRB-approved, HIPAA-compliant retrospective study included soccer players (< 18 years of age) who underwent MRI examinations in the past 5 years (2018-2023). Two radiologists retrospectively and independently reviewed all examinations to categorize skeletal maturity and to identify osseous and soft tissue findings. Findings were compared between maturation groups, and logistic regression models were used to identify predictors of surgery.

RESULTS

Ninety-seven players (45 boys, 52 girls) included 39 skeletally immature, 21 maturing, and 37 mature knees. Kappa coefficient for interobserver reliability ranged between 0.65 and 1.00. Osgood-Schlatter disease (OSD) was more common among immature than maturing and mature knees (25% vs 14% and 5%, p = 0.04); anterior cruciate ligament (ACL) injury was more common among maturing and mature than immature knees (59% and 48%, vs 15%, p < 0.01); and meniscal tears were more common among mature than immature and maturing knees (medial, 41% vs 18% and 14%, p = 0.03; lateral, 43% vs 21% and 19%, p = 0.04). Players in the mature group were more likely to undergo surgery (p = 0.01). The presence of an effusion (OR = 19.5, 95% CI 2.8-240.9, p = 0.01), ACL injury (OR = 170.0, 95% CI 1.3-6996.9, p < 0.01), and lateral meniscal tears (OR = 10.8, 95% CI 1.8-106.1, p = 0.02) were independent predictors of surgery.

CONCLUSION

Differential patterns of injury were found among symptomatic pediatric soccer players; the presence of an effusion, ACL injury, and lateral meniscal tears were independent predictors of surgery, likely contributing to the higher rates of surgery among skeletally mature players.

Parameniscal Cyst Arthroscopic Excision by the Modified Fat Pad Approach Can Shorten Recovery Time-A New Surgical Method with Retrospective Study

OBJECTIVES

Parameniscal cysts can be removed without meniscectomy, but for large or multiloculated meniscal cysts, traditional arthroscopic excision may leave the meniscus unstable. This study aimed to describe a modified fat pad approach for parameniscal cyst arthroscopic excision that retains a stable structure of the synovial margin of the meniscus and to compare the clinical outcomes between the traditional cyst excision and modified excision techniques.

METHODS

Fifty-six patients with parameniscal cysts between 2014 and 2018 were retrospectively included in this study with 28 patients in each group. All patients underwent arthroscopic parameniscal cyst excisions with traditional and modified excision techniques respectively in each group. The International Knee Documentation Committee subjective (IKDC) score, Lysholm score, visual analogue scale (VAS) score, Tegner score, active range of motion (ROM) and time to recover full ROM were used to evaluate the clinical outcomes by using the t-test.

RESULTS

The patient population included 21 males and 35 females, with a mean follow-up of 29 months. Of these, 28 patients underwent traditional arthroscopic cyst excisions and meniscal sutures, and 28 patients underwent arthroscopic excisions by the modified fat pad approach. There were no significant differences in the IKDC score, Lysholm score, Tegner score or VAS score between the traditional and modified excision groups at the final follow-up time point. However, the postoperative time to recover full ROM in the modified excision group was significantly lower than those in the traditional excision group (p < 0.05).

CONCLUSION

Arthroscopic excision with the modified fat pad approach yielded a shorter pain phase and less time to recover full ROM during recovery compared with the traditional arthroscopic excision. The new method seemed to be effective, as evidenced by the positive clinical outcomes of patients.

Meniscectomy is associated with a higher rate of osteoarthritis compared to meniscal repair following acute tears: a meta-analysis

PURPOSE

Meniscal tears are common and may impair knee function and biomechanics. This meta-analysis compared meniscal repair versus resection in patients with symptomatic meniscal tears in terms of patient-reported outcomes measures (PROMs), joint width, surgical failure, and rate of progression to osteoarthritis (OA) at conventional radiography.

METHODS

This study was conducted according to the 2020 PRISMA statement. In August 2023, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. Two reviewers independently performed the analysis and a methodological quality assessment of the included studies. All the clinical investigations which compared repair versus resection of meniscal tears were accessed.

RESULTS

Data from 20 studies (31,783 patients) were collected. The mean BMI was 28.28 ± 3.2 kg/m2, and the mean age was 37.6 ± 14.0 years. The mean time elapsed from injury to surgery was 12.1 ± 10.2 months and the mean medial joint width was 4.9 ± 0.8 mm. Between studies comparability at baseline was found in age, women, BMI, time from injury to surgery and length of the follow-up, PROMs, medial joint width, and stage of OA. The resection group demonstrated a greater Lysholm score (P = 0.02). No difference was found in the International Knee Documentation Committee (P = 0.2). Nine studies reported data on the rate of failures at a mean of 63.00 ± 24.7 months. No difference was found between the two groups in terms of persistent meniscal symptoms (P = 0.8). Six studies reported data on the rate of progression to total knee arthroplasty at a mean of 48.0 ± 14.7 months follow-up. The repair group evidenced a lower rate of progression to knee arthroplasty (P = 0.0001). Six studies reported data on the rate of advanced knee OA at a mean of 48.0 ± 14.7 months of follow-up. The repair group evidenced a lower rate of advanced knee OA (P = 0.0001). No difference was found in the mean joint space width (P = 0.09).

CONCLUSION

Meniscal repair is associated with a lower progression to knee osteoarthritis at approximately six years of follow-up compared to partial meniscectomy. No difference in PROMs, medial joint width, and failures were evidenced.

LEVEL OF EVIDENCE

Level III, meta-analysis.

Morphological assessment of cartilage and osteoarthritis in clinical practice and research: Intermediate-weighted fat-suppressed sequences and beyond

Magnetic resonance imaging (MRI) is widely regarded as the primary modality for the morphological assessment of cartilage and all other joint tissues involved in osteoarthritis. 2D fast spin echo fat-suppressed intermediate-weighted (FSE FS IW) sequences with a TE between 30 and 40ms have stood the test of time and are considered the cornerstone of MRI protocols for clinical practice and trials. These sequences offer a good balance between sensitivity and specificity and provide appropriate contrast and signal within the cartilage as well as between cartilage, articular fluid, and subchondral bone. Additionally, FS IW sequences enable the evaluation of menisci, ligaments, synovitis/effusion, and bone marrow edema-like signal changes. This review article provides a rationale for the use of FSE FS IW sequences in the morphological assessment of cartilage and osteoarthritis, along with a brief overview of other clinically available sequences for this indication. Additionally, the article highlights ongoing research efforts aimed at improving FSE FS IW sequences through 3D acquisitions with enhanced resolution, shortened examination times, and exploring the potential benefits of different magnetic field strengths. While most of the literature on cartilage imaging focuses on the knee, the concepts presented here are applicable to all joints. KEY POINTS: 1. MRI is currently considered the modality of reference for a "whole-joint" morphological assessment of osteoarthritis. 2. Fat-suppressed intermediate-weighted sequences remain the keystone of MRI protocols for the assessment of cartilage morphology, as well as other structures involved in osteoarthritis. 3. Trends for further development in the field of cartilage and joint imaging include 3D FSE imaging, faster acquisition including AI-based acceleration, and synthetic imaging providing multi-contrast sequences.

Medial meniscal posterior horn tears and ramp lesions in pediatric patients: lessons learned

Meniscal injuries are increasingly reported in pediatric patients due to early sports participation and are commonly encountered during anterior cruciate ligament reconstruction. Preoperative identification of meniscal tears is crucial, particularly when involving the posteromedial meniscocapsular junction (ramp lesion). MRI plays an important role in detecting this particular type of meniscal injury. Consequently, pediatric radiologists should be aware of particular MRI findings related to ramp lesions including the presence of a medial meniscal tear, peripheral meniscal irregularity, meniscocapsular junctional fluid-like signal intensity, and capsular ligament tears. Thus, we illustrate the lessons we have learned from our institutional multidisciplinary arthroscopic-MR correlation conference for retrospectively identified posterior horn medial meniscal tears and ramp lesions.

Risk stratification by nomogram of deep learning radiomics based on multiparametric magnetic resonance imaging in knee meniscus injury

PURPOSE

To construct and validate a nomogram model that integrated deep learning radiomic features based on multiparametric MRI and clinical features for risk stratification of meniscus injury.

METHODS

A total of 167 knee MR images were collected from two institutions. All patients were classified into two groups based on the MR diagnostic criteria proposed by Stoller et al. The automatic meniscus segmentation model was constructed through V-net. LASSO regression was performed to extract the optimal features correlated to risk stratification. A nomogram model was constructed by combining the Radscore and clinical features. The performance of the models was evaluated by ROC analysis and calibration curve. Subsequently, the model was simulated by junior doctors in order to test its practical application effect.

RESULTS

The Dice similarity coefficients of automatic meniscus segmentation models were all over 0.8. Eight optimal features, identified by LASSO regression, were employed to calculate the Radscore. The combined model showed a better performance in both the training cohort (AUC = 0.90, 95%CI: 0.84-0.95) and the validation cohort (AUC = 0.84, 95%CI: 0.72-0.93). The calibration curve indicated a better accuracy of the combined model than either the Radscore or clinical model alone. The simulation results showed that the diagnostic accuracy of junior doctors increased from 74.9 to 86.2% after using the model.

CONCLUSION

Deep learning V-net demonstrated great performance in automatic meniscus segmentation of the knee joint. It was reliable for stratifying the risk of meniscus injury of the knee by nomogram which integrated the Radscores and clinical features.

High survival rate after the combination of intrameniscal and intraarticular infiltrations of platelet-rich plasma as conservative treatment for meniscal lesions

PURPOSE

To evaluate the efficacy of applying a combination of intrameniscal and intraarticular infiltrations of Platelet-Rich Plasma (PRP) in patients with meniscal tears, analyzing its failure rate and clinical evolution, as well as factors that may influence the positive response to this treatment.

METHODS

Three hundred and ninety-two cases out of 696 met the inclusion criteria and were included in this work. Survival and patient-reported outcome measure (PROM) were collected and analyzed. Survival rate was defined as the percentage of patients who did not undergo meniscus surgery during their follow-up time. Patients were asked to complete the Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline, 6 months and 18 months. Other patient- and pathology-related variables were collected. Blood and PRP samples were randomly tested as a quality control measure. Survival and comparative statistical tests, and multivariate regression were performed for the analysis of the variables.

RESULTS

The PRP applied had a platelet concentration factor of 1.9X in respect to blood levels, with no leukocytes or erythrocytes. Thirty-eight patients required surgical intervention after treatment reaching a survival rate of 90.3% with an estimated mean survival time of 54.4 months. The type of injury (P = 0.002) and the presence of chondropathy were risk factors for surgical intervention after PRP treatment (P = 0.043). All KOOS scores showed a significant statistical increase from baseline to 6 months (N = 93) and 18 months (N = 66) (P < 0.0001). The number of cases with minimal clinically important improvement (MCII) at 6 months and 18 months post-treatment was 65 (69.9%) and 43 (65.2%), respectively.

CONCLUSION

The combination of intrameniscal and intraarticular PRP infiltrations is a valid conservative treatment for meniscal injuries avoiding the need for surgical intervention. Its efficacy is higher in horizontal tears and decreases when joint degeneration is present.

LEVEL OF EVIDENCE

Level IV.

Imaging-detected sports injuries and imaging-guided interventions in athletes during the 2022 FIFA football (soccer) World Cup

OBJECTIVE

To describe imaging-detected musculoskeletal injuries and image-guided interventional procedures during the 2022 FIFA football (soccer) World Cup.

MATERIALS AND METHODS

Retrospective analysis of all radiologic examinations performed in a central medical facility for athletes was performed by two board certified musculoskeletal radiologists. Data on muscle, tendon, ligament, cartilage, and bone injuries were collected according to imaging modality and body part.

RESULTS

A total of 143 radiology examinations in 94 athletes were evaluated at the central medical facility. Magnetic resonance imaging (MRI) was the most utilized modality (67%), followed by radiography (12%), ultrasonography (9%), and computed tomography (4%). Image-guided interventions corresponded to 8% of all radiological examinations. There were 112 injuries described, affecting muscles and tendons (42%), ligaments (25%), cartilage (21%), and bone (12%). Most injured body parts were thigh (27%), foot and ankle (23%), knee (23%), and hip/groin (8%). Most injured players were within the age range of 24-35 years old (71%).

CONCLUSION

Imaging was utilized in 11% of players who participated in the 2022 FIFA World Cup in Qatar. MRI was the most utilized modality, and acute muscle tears were the most diagnosed type of injury. Diagnostic imaging played an important role in diagnosing sports-related injuries during the 2022 FIFA World Cup.

Ring-Shaped Meniscus, MRI Features, and Diagnosis: A Report of 2 Cases

CASE

A ring-shaped meniscus (RSM) is a rare malformation of debatable origin usually occurring on the lateral meniscus. Here, we present 2 cases of RSM with differing etiologies and discuss the current literature on the topic. These reports may help with the identification of RSMs in the future and assist in understanding the true etiopathogenesis of individual cases.

CONCLUSION

These 2 cases exemplify the variation in presentations of ring-shaped menisci and their radiological features on both x-ray and magnetic resonance imaging. This reinforces the idea that there may be both a congenital and an iatrogenic etiology to this rare condition.

Automatic Detection of Meniscus Tears Using Backbone Convolutional Neural Networks on Knee MRI

BACKGROUND

Timely diagnosis of meniscus injuries is key for preventing knee joint dysfunction and improving patient outcomes because it decreases morbidity and facilitates treatment planning.

PURPOSE

To train and evaluate a deep learning model for automated detection of meniscus tears on knee magnetic resonance imaging (MRI).

STUDY TYPE

Bicentric retrospective study.

SUBJECTS

In total, 584 knee MRI studies, divided among training (n = 234), testing (n = 200), and external validation (n = 150) data sets, were used in this study. The public data set MRNet was used as a second external validation data set to evaluate the performance of the model.

SEQUENCE

A 3 T, coronal, and sagittal images from T1-weighted proton density (PD) fast spin-echo (FSE) with fat saturation and T2-weighted FSE with fat saturation sequences.

ASSESSMENT

The detection system for meniscus tear was based on the improved YOLOv4 model with Darknet-53 as the backbone. The performance of the model was also compared with that of three radiologists of varying levels of experience. The determination of the presence of a meniscus tear from surgery reports was used as the ground truth for the images.

STATISTICAL TESTS

Sensitivity, specificity, prevalence, positive predictive value, negative predictive value, accuracy, and receiver operating characteristic curve were used to evaluate the performance of the detection model. Two-way analysis of variance, Wilcoxon signed-rank test, and Tukey's multiple tests were used to evaluate differences in performance between the model and radiologists.

RESULTS

The overall accuracies for detecting meniscus tears using our model on the internal testing, internal validation, and external validation data sets were 95.4%, 95.8%, and 78.8%, respectively. One radiologist had significantly lower performance than our model in detecting meniscal tears (accuracy: 0.9025 ± 0.093 vs. 0.9580 ± 0.025).

DATA CONCLUSION

The proposed model had high sensitivity, specificity, and accuracy for detecting meniscus tears on knee MRIs.

EVIDENCE LEVEL

3 TECHNICAL EFFICACY: Stage 2.

Short-Term Outcomes after High Tibial Osteotomy Aimed at Neutral Alignment Combined with Arthroscopic Centralization of Medial Meniscus in Osteoarthritis Patients

The study aimed to improve the long-term outcomes of open-wedge high tibial osteotomy (OWHTO); procedures combining OWHTO aimed at neutral alignment and arthroscopic centralization for meniscal extrusion have been introduced. The present study evaluated short-term patient-reported outcome measures; namely, the patient subjective satisfaction scores and Numeric Rating Scale (NRS) for walking pain after OWHTO aimed at neutral alignment with and without arthroscopic centralization for an extruded medial meniscus. A retrospective review of 50 primary OWHTO patients was conducted. Thirty-nine patients were included in the analysis after applying the exclusion criteria. The centralization group included 21 patients with knee osteoarthritis patients who underwent the OWHTO with arthroscopic meniscal centralization, while the control group included 18 patients who underwent OWHTO alone. The patient subjective satisfaction scores and NRS for walking pain were recorded at outpatient visits from before surgery to 3 years after surgery. In terms of the Lysholm knee scale, International Knee Documentation Committee subjective score, and Knee Osteoarthritis Outcome Score, the latest data (at least 2 years after surgery) were reviewed. Radiographic changes in joint space width and joint line congruence angle were measured 2 years postoperatively. Patient demographic data were also reviewed. One patient in the centralization group experienced a superficial surgical site infection. The patient subjective satisfaction and NRS scores for walking pain gradually improved by 1 year after surgery and were sustained until 3 years after surgery in both groups, with no significant difference between the groups. The course of patient-reported outcome measures from before surgery to 3 years after surgery for solely OWHTO aimed at neutral alignment and OWHTO aimed at neutral alignment with arthroscopic centralization showed the similar trends.

Clinical considerations of anatomy and magnetic resonance imaging in pediatric meniscus tear, with imaging-based treatment options

Background

The incidence of meniscal tears in children has been increasing. Early sport specialization, more intense training activity, and increasing participation in competitive sports may have affected to that increasing trend. Diagnosing acute menisci tear in children is based on suggestive clinical and magnetic resonance imaging findings. There are special particulars in immature menisci, due to relatively good vascular supply. Furthermore, growing skeleton makes differences in injury pattern, and a clinician needs to recognize not only meniscus but also potential injuries in growth plates and ligaments, which are usual in connection with pediatric meniscus leasion. Clinical and imaging investigation prior to treatment is crucial, because non-operative care is considerable, to achieve spontaneous healing, especially in peripherial tears of younger children. Second, repair is preferred always as possible, in spite of resection due to high rate of long-term sequelae after partial meniscectomy. High standard preoperative imaging aid in preparing to the meniscus sparing arthroscopic intervention.

Methods

In this current concept article, the clinical considerations of imaging the injured pediatric knee with a suspected meniscus tear and the treatment options by the imaging findings are reviewed.

Level of evidence

level III.

Magnetic Resonance Imaging for Acute Musculoskeletal Injuries of the Knee Joint in Coal Miners: A Retrospective Study

Aim

Coal miners are more prone to musculoskeletal injuries to their knees due to specific repetitive movements while working in the seams. We aimed to identify the kinds of and quantify traumatic musculoskeletal injuries to the knee in the coal miners.

Methods

A retrospective observational analysis of all consecutive emergency admissions of the coal miners with occupational knee injuries between January 2018 and December 2020 was performed. A total of 94 knee trauma events in 79 knees of 76 patients were analyzed in the study. Musculoskeletal injuries of the meniscal and ligamentous/tendinous structures were identified using magnetic resonance imaging of the affected knees.

Results

The medial meniscal and the anterior cruciate ligament injuries were detected in 72.3% and 51.1% of the events, respectively. Grade 2 and 3 medial meniscal injuries were the most common grades (39.7% and 41.2%, respectively). For the anterior cruciate ligament injuries, grade 2 was the most common (56.3%). In 48.9% of the cases, we detected bony bruise/edema in the tibial plateau (52.2%), and the condyles of the femur (45.7%) were almost equally affected. Intraarticular effusions appeared in 59.6% of the cases.

Conclusions

Our findings provide detailed identification of the injuries seen in the coal miners. The medial meniscus and the anterior cruciate ligament are the most frequently injured structures.

Deep convolutional feature details for better knee disorder diagnoses in magnetic resonance images

Convolutional neural networks (CNNs) applied to magnetic resonance imaging (MRI) have demonstrated their ability in the automatic diagnosis of knee injuries. Despite the promising results, the currently available solutions do not take into account the particular anatomy of knee disorders. Existing works have shown that injuries are localized in small-sized knee regions near the center of MRI scans. Based on such insights, we propose MRPyrNet, a CNN architecture capable of extracting more relevant features from these regions. Our solution is composed of a Feature Pyramid Network with Pyramidal Detail Pooling, and can be plugged into any existing CNN-based diagnostic pipeline. The first module aims to enhance the CNN intermediate features to better detect the small-sized appearance of disorders, while the second one captures such kind of evidence by maintaining its detailed information. An extensive evaluation campaign is conducted to understand in-depth the potential of the proposed solution. The experimental results achieved demonstrate that the application of MRPyrNet to baseline methodologies improves their diagnostic capability, especially in the case of anterior cruciate ligament tear and meniscal tear because of MRPyrNet's ability in exploiting the relevant appearance features of such disorders. Code is available at https://github.com/matteo-dunnhofer/MRPyrNet.

Selective Unique Signs of Meniscus Tears as Visualized by Magnetic Resonance Imaging

The meniscus is an organized collection of fibrocartilaginous tissue that is located between the femoral condyles and the tibial plateau of the knee which primarily assists with load transmission. The complex composition of articulating soft-tissue structures in the knee causes the menisci to become a common source of injury, especially in the realm of athletic trauma. Magnetic resonance imaging (MRI) has become the imaging modality of choice for evaluating patients with suspected meniscal pathology because of its numerous advantages over plain radiographs. Most forms of meniscal tears have classic MRI findings and are used in correlation with physical examination findings to confirm or rule out a diagnosis. These imaging findings are referred to as signs and have been well studied, and the associated eponyms for each sign are well published throughout the literature. This article will review and describe a unique selection of meniscal pathology as visualized by MRI that is more commonly published in musculoskeletal radiology literature when compared with orthopedics and sports medicine literature.

Anatomic Factors Associated With the Development of an Anterior Cruciate Ligament Rerupture in Men: A Case-Control Study

BACKGROUND

Although several factors are associated with anterior cruciate ligament (ACL) rerupture, the effect of anatomic factors associated with ACL rupture on ACL rerupture development has not been evaluated.

PURPOSE

To determine individual anatomic parameters independently associated with ACL rerupture and the diagnostic values of these parameters.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A total of 91 male patients with ACL rerupture and 182 age-, sex-, body mass index-, and side dominance-matched patients without rerupture who underwent ACL reconstruction with a 5-year follow-up were included. In all, 35 parameters that were previously defined as risk factors for primary ACL rupture were compared between the 2 groups. Uni- and multivariate logistic regression models were created to evaluate independently associated factors. Receiver operating characteristic curve analysis was performed for independently associated parameters to predict sensitivity, specificity, and cutoff values.

RESULTS

The mean ± standard deviation age of patients at the time of index surgery was 26.5 ± 6.7 years. Notch shape index (P = .014), tibial proximal anteroposterior (AP) distance (TPAPD) (P < .001), lateral femoral condylar AP distance (LCAPD)/TPAPD ratio (P < .001), medial meniscal cartilage bone height (P < .001), and lateral meniscal bone angle (P = .004) were found to be significantly different between the 2 groups. Only the LCAPD/TPAPD ratio (odds ratio, 2.713; 95% CI, 1.998-5.480; P < .001) was found to be independently associated with ACL rerupture development. The LCAPD/TPAPD ratio revealed 78.9% sensitivity and 75.5% specificity (area under the curve, 0.815; 95% CI, 0.760-0.870) for values above 1.52.

CONCLUSION

The LCAPD/TPAPD ratio can be used to distinguish patients who are at risk of developing ACL rerupture from patients who are not. In the clinical practice, findings of this study may help to develop surgical and nonsurgical preventive strategies in ACL rerupture development.

Discoid medial meniscus of both knees: A case report

BACKGROUND

Discoid meniscus is a congenital anomaly that typically affects the lateral meniscus. The appearance of the discoid medial meniscus in both knees is extremely rare, with an incidence of only 0.012%.

CASE SUMMARY

Our patient was a 30-year-old female. Under no obvious predisposing causes, she began to experience pain in both knees, which worsened while walking and squatting. The pain was aggravated after exercise, and joint flexion and extension activities were accompanied by knee snapping. Apley’s test was positive on physical examination, and there was a pressing pain in the medial articular space. Plain radiographs of both knees revealed no obvious abnormalities in the bilateral knee joint space. Partial meniscectomy as well as menisci reformation were performed on both knees under arthroscopy. Under the guidance of rehabilitation, the patient’s range of motion in both knees returned to normal without pain and knee snapping.

CONCLUSION

This study showed that the clinical manifestations of the discoid medial meniscus injury are identical to those of the conventional medial meniscus injury, and arthroscopic surgery is effective.

Return to sports after bucket handle medial meniscus tear repair using inside out technique in recreational sports players

The main purpose of our study is to determine the outcomes of bucket handle medial meniscus tears repaired with the inside out technique in recreational sports players, and the return of these to pre-injury sports levels. 41 athletes with medial meniscus bucket handle tear were included in the study. 28 cases were associated with ACL tear while rest were isolated tears. Medial meniscus repair was done exclusively with arthroscopy assisted inside out technique. Lysholm score, IKDC score and Tegner staging were used to evaluate functional status of patients with minimum 1-year follow-up. Data was analyzed using Wilcoxon Matched pairs test, and Friedman test. All patients were examined clinically at regular intervals. Lysholm score and IKDC score showed significant increase in their values. Tegner staging showed no significant change compared to their preinjury game level. On VAS pain scale, there was significant decrease in their pain at regular follow up intervals. 2 patients had re-tears of the repaired medial meniscus. Repairing bucket handle tears of the medial meniscus in recreational sports players with the inside out technique yields good results in terms of clinical and functional outcomes. It successfully allows them to return to sports at 1 year.

The Effects of Korean Medicine Treatment for Meniscus Tears: A Retrospective Chart Review

Changes in symptoms and dysfunction related to meniscus tears following the use of Korean medicine for ≥ 4 days were studied. The medical charts of 53 cases of diagnosed meniscus tears (magnetic resonance imaging) with an admission Numeric Rating Scale (NRS) score ≥ 4, between 2017 and 2022 were retrospectively reviewed. Treatments included acupuncture, pharmacopuncture, herbal treatment, Chuna therapy, and physiotherapy. The NRS, Western Ontario and McMaster Universities Osteoarthritis Index, and European Quality of Life 5 Dimensions were performed at admission and discharge. There were 42 females and 11 males in this study. Patients were more likely to be in their 60s (38.18%), have an unknown etiology (81.13%), and have complex tears (50.94%). After receiving a combination of alternative Korean medicine during hospitalization, the mean NRS score improved from 6.82 ± 1.19 to 3.66 ± 1.83 (p < 0.001), the Western Ontario and McMaster Universities Osteoarthritis Index score improved from 46.47 ± 20.99 to 37.98 ± 19.23 (p < 0.001), and the mean European Quality of Life Five Dimensions score improved from 0.61 ± 0.18 to 0.68 ± 0.14 (p < 0.001) after treatment. These results suggest that Korean medicine treatment of meniscus tears alleviated pain and improved physical function.

Inferring pediatric knee skeletal maturity from MRI using deep learning

PURPOSE

Many children who undergo MR of the knee to evaluate traumatic injury may not undergo a separate dedicated evaluation of their skeletal maturity, and we wished to investigate how accurately skeletal maturity could be automatically inferred from knee MRI using deep learning to offer this additional information to clinicians.

MATERIALS AND METHODS

Retrospective data from 894 studies from 783 patients were obtained (mean age 13.1 years, 47% female). Coronal and sagittal sequences that were T1/PD-weighted were included and resized to 224 × 224 pixels. Data were divided into train (n = 673), tune (n = 48), and test (n = 173) sets, and children were separated across sets. The chronologic age was predicted using deep learning approaches based on a long short-term memory (LSTM) model, which took as input DenseNet-121-extracted features from all T1/PD coronal and sagittal slices. Each test case was manually assigned a bone age by two radiology residents using a reference atlas provided by Pennock and Bomar. The patient's age served as ground truth.

RESULTS

The error of the model's predictions for chronological age was not significantly different from that of radiology residents (model M.S.E. 1.30 vs. resident 0.99, paired t-test = 1.47, p = 0.14). Pearson correlation between model and resident prediction of chronologic age was 0.96 (p < 0.001).

CONCLUSION

A deep learning-based approach demonstrated ability to infer skeletal maturity from knee MR sequences that was not significantly different from resident performance and did so in less than 2% of the time required by a human expert. This may offer a method for automatically evaluating lower extremity skeletal maturity automatically as part of every MR examination.

Several Techniques Exist With Favorable Biomechanical Outcomes in Radial Meniscus Tear Repair-A Systematic Review

PURPOSE

To compare biomechanical properties of various radial tear repair techniques in the medial and lateral menisci.

METHODS

A search was performed for key words regarding mechanical properties of repair of radial meniscal tears in PubMed, Embase, CINAHL, Scopus, and Cochrane databases, yielding 1791 articles. Articles were screened using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines against inclusion criteria and underwent Methodological Index for Non-Randomized Studies (MINORS) methodologic quality assessment. Repair constructs evaluated were classified based on repair technique, use of a transtibial augmentation, and the number, orientation, and pattern of stitches. Results published across different studies were compared but not subjected to meta-analysis due to variability in testing procedures and heterogeneity of repair methods.

RESULTS

We identified 20 studies that performed mechanical testing on 21 different radial meniscal tear repair techniques. The greatest reported mean load-to-failure (LtF) were the transtibial 2-tunnel + 4 horizontal inside-out sutures (191.2 N ± 17.3, cadaver) and all-inside double vertical repair (146.3 N ± 36.2, porcine). The transtibial technique improved LtF and displacement of an inside-out (IO) horizontal repair. All-inside vertical repairs demonstrated greater LtF, stiffness, and displacement compared with IO horizontal repairs in 2 studies. Compared with IO double horizontal repairs, all-inside double vertical or IO double horizontal repairs with reinforcing stitches parallel to the tear exhibited greater LtF in 3 studies and stiffness in 2 studies. Two studies reported that parallel reinforcing stitches significantly reduced suture tear-through compared with similar, nonreinforced repairs. Mean MINORS score for all studies analyzed was 19.88 ± 1.47 points.

CONCLUSIONS

A systematic review demonstrated that there may be alternatives to traditional IO horizontal repairs for radial meniscus tears. Less-invasive all-inside vertical techniques reinforced with suture parallel to the tear instead of standard IO horizontal sutures may improve strength of repair. In addition, transtibial 2-tunnel augmentation may also increase strength of radial meniscus tear repairs.

CLINICAL RELEVANCE

There may be alternatives to IO horizontal repairs for radial meniscus tears.

Meniscal Root Tears: An Update Focused on Preoperative and Postoperative MRI Findings

Meniscal root tears represent radial tears or avulsions of the meniscal cartilage at the tibial attachment site that profoundly affect meniscal biomechanics and kinematics. Meniscal root tears have the functional effect of a total meniscectomy and can lead to rapid degenerative change with development of early knee osteoarthritis (OA). A growing range of arthroscopic surgical techniques have been developed to repair meniscal root tears with the aim of restoring joint kinematics and contact pressures and delaying the development of OA. With increased understanding of the anatomy and biomechanics of the meniscal root, meniscal root injury repair has become the treatment of choice in knees with nonadvanced OA. This article reviews the anatomy and biomechanics of the meniscal roots, clinical and imaging diagnostic criteria of meniscal root tears, correlation between arthroscopy and MRI in the diagnosis and classification of meniscal root tears, and expected and abnormal MRI findings after meniscal root repair. Familiarity with MRI signs and classifications of meniscal root tears, as well as with root repair surgical techniques, can aid radiologists in correctly reporting preoperative and postoperative MRI findings.

MRI evaluation of meniscal anatomy: which parameters reach the best inter-observer concordance?

Purpose

The aim of the study is to evaluate which MRI parameters achieve the best degree of inter-individual concordance in the description of meniscal fibrocartilage, regarding its morphology, signal and position.

Materials and methods

Eighty-nine knee MRIs were included in the study, retrospectively re-evaluated by three radiologists who completed a binary report (normal/abnormal) describing the meniscus signal, position relative to the tibial plateau margin and morphology. The inter-individual concordance value was calculated using Cohen's test.

Results

We obtained different inter-individual concordance values according to the parameters considered. The concordance was poor in the description of the meniscal position relative to the tibial plateau margin (average k = 0.6); the result was comparable in the description of the meniscal morphology (average k = 0.56). The best results were obtained with the meniscal signal analysis (average k = 0.8).

Conclusion

To the best of our knowledge, there are no studies in the literature assessing the concordance between multiple readers in the description of the parameters we studied. The results we obtained suggest that the most reliable parameter for describing meniscal fibrocartilage is its signal intensity, whereas morphology and position may lead to different interpretations that are not always unequivocal.

Diagnostic advantage of thin slice 2D MRI and multiplanar reconstruction of the knee joint using deep learning based denoising approach

The purpose of this study is to evaluate whether thin-slice high-resolution 2D fat-suppressed proton density-weighted image of the knee joint using denoising approach with deep learning-based reconstruction (dDLR) with MPR is more useful than 3D FS-PD multi planar voxel image. Twelve patients who underwent MRI of the knee at 3T and 13 knees were enrolled. Denoising effect was quantitatively evaluated by comparing the coefficient of variation (CV) before and after dDLR. For the qualitative assessment, two radiologists evaluated image quality, artifacts, anatomical structures, and abnormal findings using a 5-point Likert scale between 2D and 3D. All of them were statistically analyzed. Gwet's agreement coefficients were also calculated. For the scores of abnormal findings, we calculated the percentages of the cases with agreement with high confidence. The CV after dDLR was significantly lower than the one before dDLR (p < 0.05). As for image quality, artifacts and anatomical structure, no significant differences were found except for flow artifact (p < 0.05). The agreement was significantly higher in 2D than in 3D in abnormal findings (p < 0.05). In abnormal findings, the percentage with high confidence was higher in 2D than in 3D (p < 0.05). By applying dDLR to 2D, almost equivalent image quality to 3D could be obtained. Furthermore, abnormal findings could be depicted with greater confidence and consistency, indicating that 2D with dDLR can be a promising imaging method for the knee joint disease evaluation.

Medial meniscus extrusion and stage are related to the size of spontaneous osteonecrosis of the knee in patients who underwent high tibial osteotomy

PURPOSE

Spontaneous osteonecrosis of the knee (SONK) causes acute atraumatic knee pain, and meniscus tears may be associated with the pathogenesis of SONK. The purpose of this study was to investigate the relationship of the type of meniscus tear and medial meniscus extrusion with SONK on the medial femoral condyle in patients who underwent surgical treatment with high tibial osteotomy due to severe knee pain.

METHODS

We enrolled 98 patients with 102 knees who underwent medial opening wedge high tibial osteotomy (OWHTO) under the diagnosis of medial femoral condyle osteonecrosis at our hospital from December 2003 to January 2020. Based on the Koshino classification, cases of SONK were classified as stage 1-4. The relationships of demographic data, X-rays and MRI images, including femorotibial angle (FTA), meniscus tear type, and medial meniscus extrusion (MME), with the stage and volume of SONK were investigated.

RESULTS

Ninety-eight patients (29 males and 69 females), with an average age at surgery of 69.2 ± 9.6 years and Body mass index(BMI) of 61.0 ± 17.6 kg/m². In 102 cases of SONK, 11 knees, 18 knees, 46 knees, and 27 knees were classified as stage 1-4, respectively. The mean SONK volume was 2161.61 µm (range 95.67-7484.68 µm) on preoperative MRI. The preoperative FTA (mean 180.86°, range 172-187°) was not associated with the stage or volume of SONK. Meniscus tears were found in all cases of SONK and consisted of 2 degenerations, 2 horizontal tears, 0 vertical tears, 40 radial tears, 4 complex tears, and 54 medial meniscus posterior root tears (MMPRTs). In addition, 99% (101/102) of knees showed more than 3 mm of meniscus extrusion. Although the meniscus tear type was not associated with SONK stage, there was a high rate of tears that caused disruption of the hoop strain, such as MMPRTs (52.9%) or radial tears (39.2%). MME was significantly related to SONK volume (r = 0.387, p < 0.001).

CONCLUSION

All patients with SONK had coexisting meniscus tears, most menisci had medial extrusion, and a positive correlation was observed between MME and SONK volume.

Repairing Complete Radial Tears of the Lateral Meniscus: Arthroscopic All-Inside Double Vertical Cross-Suture Technique Is Effective and Safe With 2-Year Minimum Follow-Up

PURPOSE

To assess the failure rate and clinical outcomes of the all-inside, double-vertical, cross-suture technique in repairing complete radial tears of the lateral meniscus.

METHOD

We retrospectively reviewed records of patients with this injury on whom the present technique was employed at our institution between 2011 and 2018, with at least 24 months of follow-up. Six months postoperatively, the meniscus healing and extrusion status were evaluated through magnetic resonance imaging. Preoperative and postoperative knee function, measured through IKDC, Lysholm knee, and Tegner activity scale scores, were compared.

RESULTS

In total, 27 patients underwent the procedure. The preoperative mean (standard deviation) IKDC score, Lysholm knee score, and Tegner activity scale scores were 53.4 ± 5.3, 63.2 ± 9.3, and 4 ± .7, respectively. At the last follow-up (≥24 months postoperatively), these scores increased to 92.1 ± 2.6, 90.8 ± 4.2, and 6.1 ± 1.3, respectively (all P < .05). Complete healing of the meniscus was observed in 23 patients, and 4 patients had meniscus retear or nonhealing. The overall retear or nonhealing rate was 14.8%. Healing rates between those with isolated radial tears (87.5%) and those with combined anterior cruciate ligament rupture (84.2%; P = .826) were comparable. No difference was observed in the progression of coronal and sagittal meniscus extrusion (P = .133 and .797, respectively).

CONCLUSION

In patients with complete radial tears of the lateral meniscus, the arthroscopic all-inside double vertical cross-suture repair technique resulted in an 85.2% healing rate, improvements in functional outcomes and activity levels, and no identifiable progression of meniscus extrusion. The all-inside double vertical cross-suture technique is effective and safe for the repair of radial tears of the meniscus.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

The meniscal ossicle associated with medial meniscus posterior root tear

Ossicle of the meniscus is an uncommon discovery often misdiagnosed as a loose body, which may lead to intermittent knee discomfort. We present a rare case of meniscal ossicle accompanied by the medial meniscus posterior root tear. A 46-year-old female experienced intermittent left knee pain and after coming to the hospital was diagnosed with a meniscal ossicle. The patient underwent arthroscopic ossicle resection followed by meniscal root repair. The patient had not experienced any complications post-operatively and remains asymptomatic 8 months after the surgery. The purpose of this article is to expand the knowledge of meniscal ossicle and provide a broaden review of its diagnosis and repair.

Update on imaging of the discoid meniscus

Discoid menisci represent a range of morphological meniscal variants, most commonly involving the lateral meniscus. Clinical presentation ranges from an asymptomatic incidental finding to snapping, pain, swelling and reduced range of knee movement. Symptomatic presentation of discoid menisci is usually due to meniscal tears and instability resulting from abnormal meniscal morphology and ultrastructure, with absent peri-meniscal ligamentous and meniscocapsular attachments characteristic of the Wrisberg sub-type. This article reviews the current classification systems of discoid menisci, gross morphological characteristics of each sub-type and ultrastructure. Clinical presentation, arthroscopic findings and indirect radiological diagnostic criteria are described, as are the MRI findings of normal and pathological discoid menisci. Current concepts of surgical management and outcomes of the discoid meniscus are also briefly discussed.

Radial tears in the anterior third of the lateral meniscus are frequently combined with horizontal tears

INTRODUCTION

Radial tears of the lateral meniscus are often located in the junction of the middle and posterior third or posterior tibial attachment. However, we observed that a few cases of radial tears occurred in the anterior third of the lateral meniscus, and in many cases, they were accompanied by horizontal tears.

HYPOTHESIS

Radial tears are more frequently accompanied by horizontal tears in the anterior third of the lateral meniscus than in other regions.

MATERIAL AND METHODS

From July 2006 to May 2019, patients who underwent arthroscopic surgery for radial tears of the lateral meniscus were included. Patients with radial tears in the anterior third of the lateral meniscus were classified into the anterior group and those with radial tears in the middle and posterior third were classified into the comparison group. Magnetic resonance imaging and arthroscopic findings were reviewed to evaluate whether radial tears were accompanied by other types of tears, especially horizontal tears. The incidence of complex tears between the two groups was compared.

RESULTS

Eighty knees in 79 patients were included. The mean age at the time of surgery was 44.1±16.9 years. The anterior group included 30 knees, and 19 (63.3%) of those also had horizontal tears. In the anterior group, all complex tears were accompanied by horizontal tears, and no other types of accompanying tears were observed. The comparison group included 50 knees, and 16 (32%) of those also had other types of tears. Of the 16 complex tears, 14 had horizontal tears and 2 had longitudinal tears. The incidence of complex tear was significantly higher in the anterior group than in the comparison group (p<.001).

CONCLUSION

Radial tears occurring at the anterior third of the lateral meniscus are frequently accompanied by a horizontal tear. It is important to be aware and predict the occurrence of such characteristic tears and to do proper surgical procedures.

LEVEL OF PROOF

IV; Cross-sectional study.

Current concepts on meniscal repairs

The specific meniscus injury pattern were divided into many patterns. Nowadays, the meniscus root injury, radial tear meniscus, bucket handle tear meniscus and Ramp lesion were particularly focused on many way to manage and still controversial a lot of issues. Meniscus root tears (MRTs) and Ramp lesion are the most ignored, or misdiagnosed causes of chronic knee pain. Most patients delayed seeking treatment, consequently resulting in cartilage loss, and leading to the condition progressing to osteoarthritis knee. This has resulted in the rate of MR and Ramp repair increase significantly. The bucket handle meniscus tear trend to strong saving the anatomical meniscus and avoid to menisectomy. This article, on the other hand, will reveal you how to save and secure a nearly native meniscus fixation. In case of the radial meniscus, the partial meniscectomy is still used to treat this type of injury today, but it does not prevent degenerative changes from occurring, which can lead to unfavorable outcomes. Meniscal repair is a popular procedure for treating radial tears as an alternative to surgery. However, this pattern of meniscus tear can be difficult to repair and has a high failure rate, the arthroscopic meniscus repair techniques are published.

Accelerating Knee MRI: 3D Modulated Flip-Angle Technique in Refocused Imaging with an Extended Echo Train and Compressed Sensing

Purpose

The three-dimensional (3D) sequence of magnetic resonance imaging (MRI) plays a critical role in the imaging of musculoskeletal joints; however, its long acquisition time limits its clinical application. In such conditions, compressed sensing (CS) is introduced to accelerate MRI in clinical practice. We aimed to investigate the feasibility of an isotropic 3D variable-flip-angle fast spin echo (FSE) sequence with CS technique (CS-MATRIX) compared to conventional 2D sequences in knee imaging.

Methods

Images from different sequences of both the accelerated CS-MATRIX and the corresponding conventional acquisitions were prospectively analyzed and compared. The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) of the structures within the knees were measured for quantitative analysis. The subjective image quality and diagnostic agreement were compared between CS-MATRIX and conventional 2D sequences. Quantitative and subjective image quality scores were statistically analyzed with the paired t-test and Wilcoxon signed-rank test, respectively. Diagnostic agreements of knee substructure were assessed using Cohen’s weighted kappa statistic.

Results

For quantitative analysis, images from the CS-MATRIX sequence showed a significantly higher SNR than T2-fs 2D sequences for visualizing cartilage, menisci, and ligaments, as well as a higher SNR than proton density (pd) 2D sequences for visualizing menisci and ligaments. There was no significant difference between CS-MATRIX and 2D T2-fs sequences in subjective image quality assessment. The diagnostic agreement was rated as moderate to very good between CS-MATRIX and 2D sequences.

Conclusion

This study demonstrates the feasibility and clinical potential of the CS-MATRIX sequence technique for detecting knee lesions The CS-MATRIX sequence allows for faster knee imaging than conventional 2D sequences, yielding similar image quality to 2D sequences.