A Current Review of the Meniscus Imaging: Proposition of a Useful Tool for Its Radiologic Analysis

2023 EULAR recommendations on imaging in diagnosis and management of crystal-induced arthropathies in clinical practice

OBJECTIVE

To formulate evidence-based recommendations and overarching principles on the use of imaging in the clinical management of crystal-induced arthropathies (CiAs).

METHODS

An international task force of 25 rheumatologists, radiologists, methodologists, healthcare professionals and patient research partners from 11 countries was formed according to the EULAR standard operating procedures. Fourteen key questions on the role of imaging in the most common forms of CiA were generated. The CiA assessed included gout, calcium pyrophosphate deposition disease and basic calcium phosphate deposition disease. Imaging modalities included conventional radiography, ultrasound, CT and MRI. Experts applied research evidence obtained from four systematic literature reviews using MEDLINE, EMBASE and CENTRAL. Task force members provided level of agreement (LoA) anonymously by using a Numerical Rating Scale from 0 to 10.

RESULTS

Five overarching principles and 10 recommendations were developed encompassing the role of imaging in various aspects of patient management: making a diagnosis of CiA, monitoring inflammation and damage, predicting outcome, response to treatment, guided interventions and patient education. Overall, the LoA for the recommendations was high (8.46-9.92).

CONCLUSIONS

These are the first recommendations that encompass the major forms of CiA and guide the use of common imaging modalities in this disease group in clinical practice.

High angular resolution diffusion imaging (HARDI) of porcine menisci: a comparison of diffusion tensor imaging and generalized q-sampling imaging

Background

Diffusion magnetic resonance imaging (MRI) allows for the quantification of water diffusion properties in soft tissues. The goal of this study was to characterize the 3D collagen fiber network in the porcine meniscus using high angular resolution diffusion imaging (HARDI) acquisition with both diffusion tensor imaging (DTI) and generalized q-sampling imaging (GQI).

Methods

Porcine menisci (n=7) were scanned ex vivo using a three-dimensional (3D) HARDI spin-echo pulse sequence with an isotropic resolution of 500 µm at 7.0 Tesla. Both DTI and GQI reconstruction techniques were used to quantify the collagen fiber alignment and visualize the complex collagen network of the meniscus. The MRI findings were validated with conventional histology.

Results

DTI and GQI exhibited distinct fiber orientation maps in the meniscus using the same HARDI acquisition. We found that crossing fibers were only resolved with GQI, demonstrating the advantage of GQI over DTI to visualize the complex collagen fiber orientation in the meniscus. Furthermore, the MRI findings were consistent with conventional histology.

Conclusions

HARDI acquisition with GQI reconstruction more accurately resolves the complex 3D collagen architecture of the meniscus compared to DTI reconstruction. In the future, these technologies have the potential to nondestructively assess both normal and abnormal meniscal structure.

Do MRI Results Represent Functional Outcomes Following Arthroscopic Repair of an Isolated Meniscus Tear in Young Patients?-A Prospective Comparative Cohort Study

BACKGROUND

The use of postoperative MRI to assess the healing status of repaired menisci is a long-standing issue. This study evaluates and compares functional and MRI outcomes following an arthroscopic meniscus repair procedure with the aim of postoperative MRI diagnostic accuracy clarification in young patients.

METHODS

A total of 35 patients under 18 years old who underwent isolated meniscus repair were included. The Pedi-IKDC score, Lysholm score, and Tegner activity index (TAS) were compared between the groups formed according to the Stroller and Crues three-grade classification of postoperative MRI-based evaluations. Grade 3 MRI views were classified as unhealed, grade 2 as partially healed, and grade 1 as fully healed within the repaired meniscus, whereas grade 3 cases were considered unsuccessful due to MRI evaluation.

RESULTS

MRI assessment revealed 4 cases of grade 1 (11.4%), 14 cases of grade 2 (40.8%), and 17 cases of grade 3 (48.0%) lesions. Pedi-IKDC and TAS scores were significantly higher among MRI grade 2 patients than among MRI grade 3 patients (p < 0.05). Weak negative correlations between MRI grades and all functional scales were found (p < 0.05). ROC analysis showed that Pedi-IKDC and TAS scores could correctly classify 77% and 71% of MRI grade 3 patients, respectively. The optimal cut-off values to detect grade 3 patients were 88.74 for the Pedi-IKDC score and 4.5 for the TAS score.

CONCLUSIONS

To conclude, established functional score cut-off values may help identify unhealed meniscus repair patients.

Evaluation of meniscal elasticity using shear wave elastography in obese children and adolescents: a preliminary cross-sectional study

BACKGROUND

Musculoskeletal problems such as pain, joint pathology, increased risk of fracture, and the development of structural deformities are common in childhood obesity. Increased mechanical stress on the knee joint leads to degenerative changes in the cartilage and meniscus. Meniscal elasticity values increase in meniscal degeneration. Shear wave elastography (SWE) is an ultrasound-based imaging technique based on the principle of measuring tissue elasticity.

OBJECTIVE

We aimed to investigate the changes in meniscal stiffness and thickness that can be caused by obesity in children and adolescents using SWE.

MATERIALS AND METHODS

In this prospective cross-sectional study, the menisci of obese (n=44) and age- and sex-matched healthy weight (n=44) children and adolescents were assessed by SWE. Meniscal elasticity was measured in kPa on the coronal plane. Independent samples t-test was used to compare meniscal elasticity values between groups. Additionally, Pearson's correlation test was used to examine the relationships between elasticity values and age, height, weight, and body mass index (BMI).

RESULTS

Meniscal elasticity values were significantly higher in the obese group than in the control group (P<0.001). In both groups, there was no significant difference in meniscal stiffness between the boys and girls or between the right and left sides. In the obese group, there were weak and moderate positive correlations between meniscal elasticity values and age, weight, and BMI (P<0.05). There was no significant difference in meniscal thickness between the obese and control groups.

CONCLUSION

Meniscal stiffness is increased in obese children and adolescents.

Commercially Available Deep-learning-reconstruction of MR Imaging of the Knee at 1.5T Has Higher Image Quality Than Conventionally-reconstructed Imaging at 3T: A Normal Volunteer Study

PURPOSE

This study aimed to evaluate whether the image quality of 1.5T magnetic resonance imaging (MRI) of the knee is equal to or higher than that of 3T MRI by applying deep learning reconstruction (DLR).

METHODS

Proton density-weighted images of the right knee of 27 healthy volunteers were obtained by 3T and 1.5T MRI scanners using similar imaging parameters (21 for high resolution image and 6 for normal resolution image). Commercially available DLR was applied to the 1.5T images to obtain 1.5T/DLR images. The 3T and 1.5T/DLR images were compared subjectively for visibility of structures, image noise, artifacts, and overall diagnostic acceptability and objectively. One-way ANOVA and Friedman tests were used for the statistical analyses.

RESULTS

For the high resolution images, all of the anatomical structures, except for bone, were depicted significantly better on the 1.5T/DLR compared with 3T images. Image noise scored statistically lower and overall diagnostic acceptability scored higher on the 1.5T/DLR images. The contrast between lateral meniscus and articular cartilage of the 1.5T/DLR images was significantly higher (5.89 ± 1.30 vs. 4.34 ± 0.87, P < 0.001), and also the contrast between medial meniscus and articular cartilage of the 1.5T/DLR images was significantly higher (5.12 ± 0.93 vs. 3.87 ± 0.56, P < 0.001). Similar image quality improvement by DLR was observed for the normal resolution images.

CONCLUSION

The 1.5T/DLR images can achieve less noise, more precise visualization of the meniscus and ligaments, and higher overall image quality compared with the 3T images acquired using a similar protocol.

AMR Sign - An Arthroscopic S-shaped Fold Signifying Adequate Medial Meniscus Repair

Introduction

The preferred management of medial meniscus tears has notably moved from meniscectomies towards repair. With a higher volume of meniscal repairs being done all across the world with every passing day, the lack of an objective and definitive sign suggesting the adequacy of its repair is daunting. The purpose of our study was to introduce a unique and novel arthroscopic sign formed after adequate repair of the medial meniscus, the AMR (Adequacy of Medial meniscus Repair) sign. We hypothesised that it is not only the objective end point for repair, but can also form the indicator for excellent clinical, functional, and radiological outcome even in the long term.

Materials and methods

This was a multicentric, prospective study initiated by the corresponding author, and the findings validated subsequently by the other authors. Overall, it included 804 patients of isolated medial meniscus tear operated with arthroscopic all-inside technique between January 2014 and December 2017. Patients were segregated into three groups based on whether an S-shaped curve in the free, inner edge of the medial meniscus sign was formed post-repair, lost after further tightening, or not formed upon subjective completion of repair. All the patients were followed-up and evaluated based of medial joint line tenderness, McMurray's test for medial meniscus, IKDC score, WOMET score, and radiologically using an MRI at the terminal follow-up.

Results

The mean terminal follow-up was 42.34±4.54 months. There was significant (p<0.01) improvement in all patients at the terminal follow-up post-surgery, irrespective of the group. The group in which AMR sign was formed and maintained showed a significantly better functional outcome on terminal follow-up as well as lower failure rates compared to the other two groups.

Conclusion

AMR sign is an S-shaped fold at the inner, free edge of medial meniscus, formed after an adequate repair of isolated medial meniscus tear, as viewed on arthroscopy. It is an objective sign denoting regained integrity of the collagen architecture of the medial meniscus following repair. It is also a reliable indicator of excellent long term functional, clinical, and radiological outcome and also lower failure rates in patients after arthroscopic medial meniscus repair.

Meniscal extrusion: risk factors and diagnostic tools to predict early osteoarthritis

Meniscal extrusion (ME) is strongly correlated with cartilage wear and osteoarthritis (OA), be-cause of the altered kinematic and the decreased contact area between the tibia and femur. The aim of this narrative review is to analyze the process of ME, focusing on the possible causes, and to evaluate the correlation between ME and knee OA, in order to provide early diagnosis and treatments. Studies written in English that analyzed the causes of ME, provided indications re-garding diagnosis and treatment, and evaluated the relation between ME and early OA were in-cluded. Injuries, degeneration of the meniscal substance and meniscus root tears are associated with significantly increased ME. An extruded meniscus could be a manifestation of other pa-thologies such as disruption of coronary ligaments, cartilage loss, knee malalignment, ligament injuries, or OA. ME is strongly associated with osteoarthritis features, particularly with bone marrow lesion and cartilage damage. Magnetic resonance imaging represents the gold standard for the detection of ME. The severity of the medial meniscus extrusion may also affect healing af-ter repair, and meniscus extrusion is not completely reduced by meniscus posterior root tear re-pair. In this study, we proved that ME represents an important risk factor for early knee OA. We provided alternative theories of ME, such as meniscal fibers injury first and "dynamic extrusion of the menisci". The phenomenon of aging has been described as a new concept in the etiology of ME. Finally, we stated all the main techniques and characteristics of the diagnostic process, as well as the current knowledge in the therapeutic field.

Development of convolutional neural network model for diagnosing meniscus tear using magnetic resonance image

Background

Deep learning (DL) is an advanced machine learning approach used in diverse areas, such as image analysis, bioinformatics, and natural language processing. A convolutional neural network (CNN) is a representative DL model that is advantageous for image recognition and classification. In this study, we aimed to develop a CNN to detect meniscal tears and classify tear types using coronal and sagittal magnetic resonance (MR) images of each patient.

Methods

We retrospectively collected 599 cases (medial meniscus tear = 384, lateral meniscus tear = 167, and medial and lateral meniscus tear = 48) of knee MR images from patients with meniscal tears and 449 cases of knee MR images from patients without meniscal tears. To develop the DL model for evaluating the presence of meniscal tears, all the collected knee MR images of 1048 cases were used. To develop the DL model for evaluating the type of meniscal tear, 538 cases with meniscal tears (horizontal tear = 268, complex tear = 147, radial tear = 48, and longitudinal tear = 75) and 449 cases without meniscal tears were used. Additionally, a CNN algorithm was used. To measure the model’s performance, 70% of the included data were randomly assigned to the training set, and the remaining 30% were assigned to the test set.

Results

The area under the curves (AUCs) of our model were 0.889, 0.817, and 0.924 for medial meniscal tears, lateral meniscal tears, and medial and lateral meniscal tears, respectively. The AUCs of the horizontal, complex, radial, and longitudinal tears were 0.761, 0.850, 0.601, and 0.858, respectively.

Conclusion

Our study showed that the CNN model has the potential to be used in diagnosing the presence of meniscal tears and differentiating the types of meniscal tears.

Knee meniscal retears after repair: A systematic review comparing diagnostic imaging modalities

The meniscus is a relatively avascular fibrocartilaginous structure that provides a key role in shock absorption and load transmission. However, accurate diagnosis of meniscal retear can present a clinical challenge. The purpose of this study was to conduct a systematic review on the available literature, which compare the sensitivities, specificities, and accuracies of different diagnostic modalities of diagnosing knee meniscal retears in patients who have undergone surgical meniscal repair, such as Magnetic Resonance Imaging (MRI), Magnetic Resonance Arthrography with intraarticular contrast (direct MRA), and a combination of MRI and direct MRA. Two authors independently searched two databases (PubMed and Scopus) for literature related to knee meniscus retear according to the PRISMA guidelines. Four studies were found, which resulted in 291 patients with 293 menisci. All studies were published in 2008 and 2014. In our analysis, we calculated sensitivity to be 78.79% (95% CI, 64.07–93.51), specificity to be 56.58% (95% CI, 20.21–92.94), and overall accuracy to be 66.25% (95% CI, 54.29–78.22) for MRI and sensitivity to be 87.84% (95% CI, 83.93–91.74), specificity to be 88.68% (95% CI, 81.93–95.43), and overall accuracy to be 87.22% (95% CI, 82.22–91.62) for direct MRA. We recommend the use of direct MRA for the diagnosis of meniscal retears due to its higher sensitivity, specificity, and accuracy as compared to MRI and its reduced cost and invasive nature as compared to second-look arthroscopy. However, our review is limited by the number of studies available on this topic. More studies using study designs such as randomized controlled trials, involving MRI, direct MRA, and combinations of such techniques, should be performed to accurately assess the different techniques and aid in designing guidelines to guide the diagnosis of meniscal retears following meniscal repair.

Automated segmentation of knee menisci from magnetic resonance images by using ATTU-Net: a pilot study on small datasets

We proposed a neural network model trained with a small amount of meniscus data (only 144 MR images) to improve the segmentation performance of CNNs, such as U-Net, by overcoming the challenges caused by surrounding tissues. We trained and tested the proposed model on 204 T2-weighted MR images of the knee from 181 patients. The trained model provided excellent segmentation performance for lateral menisci with a mean Dice similarity coefficient of 0.864 (range, 0.743-0.990; SD, ±0.077). The results were superior to those of contemporarily published meniscus segmentation methods based on CNNs.

Sonographic evaluation of the degree of medial meniscal extrusion during Thessaly test in healthy knees

OBJECTIVE

The Thessaly test is a commonly used orthopedic test for meniscus tear evaluation. The study's objective is to evaluate the degree of medial meniscal extrusion during different loading phases of the Thessaly test.

METHODS

A convenience sample of 60 healthy knees (35 participants) was examined and the data sets were collected from October 8, 2018 through February 8, 2019. Sonographic measurement of the degree of physiologic extrusion of the medial meniscus deep to the medial collateral ligament was taken by two examiners at six different loading phases: supine, standing, 5° knee-flexion with internal (IR)/external (ER) rotation and 20° knee-flexion with IR/ER. The difference in meniscal extrusion by knee position was compared with ANOVA. Interexaminer reproducibility assessment was analyzed using limits of agreement.

RESULTS

The mean meniscal extrusion for each position was-supine: 2.3 ± 0.5 mm, standing: 2.8 ± 0.8 mm, 5° IR: 2.3 ± 0.9 mm, 5° ER: 2.4 ± 0.7 mm, 20° IR: 1.9 ± 0.8 mm, and 20° ER: 2.3 ± 0.7 mm. Significant increase in extrusion was observed from supine to standing (p < 0.05) and from 20° IR to 20° ER (p = 0.015). Significant decreased measurement was observed from standing to 5° IR (p < 0.05), 5° ER (p < 0.05), 20° IR (p < 0.05) and 20° ER (p < 0.05). There is no significant change between 5° IR and 5° ER (p = 1.0). Agreement parameters revealed that the differences between examiner measurements were minimal; 75% of both examiners' meniscal extrusion measurements were within 1.0 mm with 97% of measurements falling within 2.0 mm.

CONCLUSION

Our study's novel findings showed various degrees of physiological extrusion of the medial meniscus in asymptomatic knees during the loading phases involved in the Thessaly test. Physiological MME does exist and should not be defaulted to pathologic meniscus as previously described. Agreement parameters suggest that measurement of meniscal extrusion during the Thessaly test is reproducible between different examiners.

Clinical Outcomes of Meniscus Repair with or without Multiple Intra-Articular Injections of Platelet Rich Plasma after Surgery

Preservation of the meniscal volume is crucial in meniscus repair. The goal of this study was to evaluate the clinical outcome of repeated intra-articular platelet-rich plasma (PRP) injections after arthroscopic repair of a traumatic meniscal tear. We retrospectively reviewed 61 primary meniscal repairs in 61 patients (PRP group: 30; non-PRP: 31) from 2017 to 2018. Patients in the PRP group received repeated intra-articular PRP injections in week 2,4,6 after the primary meniscus repair. Subsequent meniscal repair treatment or meniscectomy, knee arthroplasty, and IKDC changes of less than 11.5 points were defined as healing failures. After following up for at least 24 months, the IKDC score was 75.1 ± 13.6, and the Lysholm score was 80.6 ± 14.9 in the PRP group and 72.6 ± 15.8 (IKDC) and 77.7 ± 17.2 (Lysholm) in the non-PRP group. Healing rates of the PRP and the non-PRP groups were 93.3% (Kaplan-Meier 91.6%) and 87.1% (Kaplan-Meier 84.7%), respectively (log rank test p = 0.874). Our study is the first to use multiple intra-articular PRP injections to facilitate meniscal healing after meniscal repair. Though selection bias may be present in this study, the PRP group had similar functional outcome and healing rate compared to non-PRP group.

MRI-Detected Knee Ligament Sprains and Associated Internal Derangement in Athletes Competing at the Rio de Janeiro 2016 Summer Olympics

Purpose

Describe the frequency and severity of knee ligament sprains diagnosed by MRI in athletes participating at the 2016 Summer Olympic Games, their association with certain sports and assess correlations with additional knee structural injury.

Patients and Methods

All knee MRIs performed in the Olympic Village and polyclinics during the 2016 Olympics were retrospectively, blindly reviewed for ligament sprains and associated knee injuries. In addition to the absence or presence of these abnormalities, athletes were stratified by age, gender and sport.

Results

11,274 athletes participated in the 2016 Olympic Games: 113 athletes received at least one knee MRI with some having bilateral or repeat MRI on the same knee. Anterior cruciate and medial collateral ligament (ACL/MCL) sprains were most common, accounting for 32 of the 43 sprains (74.4%). Wrestling (10), hockey (7), athletics (7), and judo (5) accounted for over half of ligament sprains. ACL sprains showed a significant positive correlation with medial, lateral meniscal tears and bone contusions. The positive correlation between posterior cruciate ligament (PCL) sprains with MCL/lateral collateral ligament sprain, and popliteus tendon tear was statistically significant with 50% of total PCL sprains occurring in hockey. When athletes were stratified by gender, ligament sprains had a similar occurrence and distribution between men and women.

Conclusion

Knee ligament sprains, at the Rio 2016 Games, were most common in wrestling, hockey, athletics and judo with ACL and MCL sprains most frequent. Meniscal tears and bone contusions occurred often with ACL sprains. PCL sprains tended to be multi-ligamentous injuries. Sustained ligament sprains had similar occurrence between genders, while men had a peak incidence of sprains at a younger age and women at an older age.

The "sleeper's sign" is valid and suggestive of a medial sub-meniscal flap tear

PURPOSE

To describe, evaluate and validate the diagnostic performance of a new clinical sign, the sleeper's sign, for the diagnosis of a medial submeniscal flap tear (MSMFT).

METHODS

This retrospective single-center series included patients aged 18-55 years old who underwent arthroscopic treatment in 2013-2015 for a medial meniscal tear. This study was performed according to STARD (standards for reporting of diagnostic accuracy) guidelines, and the reference test was a peroperative diagnosis of a MSMFT. The preoperative consultation reports were all analyzed to search for the sleeper's sign, defined as night time medial tibiofemoral pain when the patient is in the fetal position with both knees in contact and no pain during daytime activities.

RESULTS

Three-hundred and ten patients responded to the study criteria, mean age 41.7 ± 9.7 years old. The sleeper's sign was identified in 39 (12.6%) patients and a MSMFT was confirmed during arthroscopy in 47 (15.2%) cases, with significant agreement between this sign, arthroscopy (kappa = 0.78, p = 10^-4) and MR-imaging (kappa = 0.72, p < 0.0001). The performance parameters of the sleeper's sign were: sensitivity 74.5 ± 12.5%, specificity 98.5 ± 1.6%, Youden index 0.73 and accuracy 96.9%. MR imaging was found to be more sensitive (91.5 ± 8%). Multivariate analysis identified the sleeper's sign as a risk factor of MSMFT during arthroscopy: OR 131.9 CI 95% [26.9-646.2], p < 0.0001 and a bone edema next to the flap tear on MR-imaging: OR 13, CI 95% [1.9-7.1], p = 0.008.

CONCLUSION

The "sleeper's sign" is a new, valid, highly specific clinical sign for the diagnosis of a medial submeniscal flap tear. MRI was found to be more sensitive than the sleeper's sign.

LEVEL OF EVIDENCE

II.

Knee cartilage damage and concomitant internal derangement on MRI in athletes competing at the Rio de Janeiro 2016 Summer Olympics

•

Cartilage damage is frequently observed on MRI in Olympic Athletes.

•

Patellofemoral cartilage damage is most common and associated with certain sports including volleyball and weightlifting.

•

Meniscal tears are associated with localized cartilage damage.

•

Trend for prevalence of cartilage damage to increase with increasing age of the athlete.

Purpose

To report the MRI patterns of knee cartilage damage and concomitant internal derangement in athletes participating at the Rio de Janeiro 2016 Olympic Games.

Methods

Knee MRIs obtained at the core imaging facility of the International Olympic Committee were blindly, retrospectively reviewed by a board-certified musculoskeletal radiologist for meniscal, ligamentous, and tendon abnormalities. Cartilage assessment was based on the modified Outerbridge criteria.

Results

Of 122 athletes who received a knee MRI, 64 (52.4 %) had cartilage damage. Cartilage damage was more prevalent in the patellofemoral compartment (52 athletes, 42.6 %), followed by lateral (23 athletes, 18.9 %) and medial tibiofemoral compartments (12 athletes, 9.8 %). Patellofemoral cartilage damage was most prevalent in beach-volleyball (100 %), followed by volleyball (8 athletes, 66.7 %) and weightlifting (7 athletes, 70 %). Patellofemoral cartilage damage was most prevalent with quadriceps (8 athletes, 72.7 %) and patellar tendinosis (11 athletes, 61.1 %). Medial and lateral tibiofemoral cartilage damage was significantly associated with medial (8 athletes, 29.6 %) and lateral meniscal tears (16 athletes, 55.2 %), respectively. There was a trend for the percentage of athletes with cartilage damage to increase with age.

Conclusion

The majority of athletes at the 2016 Rio Summer Olympics who had a knee MRI showed cartilage damage. Patellofemoral compartment cartilage damage was most common and frequently observed in certain sports including volleyball, beach volleyball, and weightlifting. Overuse in these sports can contribute to patellofemoral cartilage damage and subsequent development of anterior knee pain. Cartilage damage was also observed with concomitant meniscal tears and older age.

Computational technology for nasal cartilage-related clinical research and application

Surgeons need to understand the effects of the nasal cartilage on facial morphology, the function of both soft tissues and hard tissues and nasal function when performing nasal surgery. In nasal cartilage-related surgery, the main goals for clinical research should include clarification of surgical goals, rationalization of surgical methods, precision and personalization of surgical design and preparation and improved convenience of doctor-patient communication. Computational technology has become an effective way to achieve these goals. Advances in three-dimensional (3D) imaging technology will promote nasal cartilage-related applications, including research on computational modelling technology, computational simulation technology, virtual surgery planning and 3D printing technology. These technologies are destined to revolutionize nasal surgery further. In this review, we summarize the advantages, latest findings and application progress of various computational technologies used in clinical nasal cartilage-related work and research. The application prospects of each technique are also discussed.

Quantitative Evaluation of Meniscal Healing Process of Degenerative Meniscus Lesions Treated with Hyaluronic Acid: A Clinical and MRI Study

Purpose: We aimed to evaluate clinical efficacy and healing effects of conservative management of degenerative meniscus lesions (DMLs) with a hyaluronic acid (HA) hydrogel. Methods: Patients were subjected to two HA injections two weeks apart. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Patient’s Global Assessment (PtGA) and Clinical Observer Global Assessment (CoGA) of the disease were assessed at baseline, 30, and 60 days after treatment. Short Form (36) Health Survey (SF-36) was assessed at baseline and 60 days after treatment. One year after treatment, patients were called to know whether any of them had undergone arthroscopic partial meniscectomy (APM). All patients underwent magnetic resonance imaging using a 1.5-T Magnetic Resonance Imaging (MRI) scanner (Siemens Aera), which included a T2 mapping pulse sequence with multiple echoes at baseline and 60 days after treatment. Results: 40 patients were enrolled. WOMAC score, physical function subscale, PtGA and CoGA, and SF-36 showed a statistically significant difference between baseline and follow-up. One year after treatment, only one patient had undergone APM. A decrease in the T2 measurement was detected in the posterior horn medial meniscus in 39% of cases in both the red and red–white zone, and in 60% of cases in the white zone; in the posterior horn lateral meniscus in 55% of cases in both the red and white zones, and in 65% of cases in the red–white zone. Only for the latter, there was a statistically significant difference between baseline and posttreatment T2 measurements. Conclusion: This study supports the use of HA in the conservative management of DML as it is clinically effective and enhances meniscus healing as demonstrated by T2 measurements. Moreover, it reduces the need for APM at 1-year follow-up.

Huge intrameniscal cyst successfully treated by open debridement and combined arthroscopic and open repair: a case report

BACKGROUND

Meniscal cysts are not uncommon in clinical practice, with reported incidence rates varying from 1 to 22%. Most meniscal cysts are parameniscal cysts, which are created by extravasation of synovial fluid through the meniscal tear into the adjacent soft tissue. In contrast, intrameniscal cysts in which the fluid collects in the meniscus are very rare. We encountered a teenager with a huge intrameniscal cyst accompanied by a small vertical meniscal tear in the red-white zone of the upper surface of the medial meniscus. A literature search revealed no information regarding the appropriate treatment methods and results for this type of lesion.

CASE PRESENTATION

A 14-year-old boy presented to our outpatient clinic because of right knee pain that had been present for the previous 2 months. The patient participated in Hapkido, but had no specific trauma history. Magnetic resonance imaging revealed a huge intrameniscal cyst located in the central parenchyma of the posteromedial corner of the medial meniscus. In addition, one sagittal slice on MRI revealed a vertical tear in the red-white zone of the upper surface of the medial meniscus. The presence of such a tear accompanied by a huge intrameniscal cyst is very unusual. The patient was treated via arthroscopic inside-out meniscal suture repair and open cystic debridement with additional meniscocapsular suturing. During 4 years of magnetic resonance imaging follow-up, the lesion has completely disappeared and the meniscus has successfully recovered its normal form.

CONCLUSIONS

Our treatment method may be considered as the first choice for young patients who require surgical treatment for large intrameniscal cysts with accompanying small vertical meniscal tears.

Comparison of Micro-Computed Tomography and Clinical Computed Tomography Protocols for Visualization of Nasal Cartilage Before Surgical Planning for Rhinoplasty

Importance

There is no imaging standard to model nasal cartilage for the planning of rhinoplasty procedures. Preoperative visualization of cartilage may improve objective evaluation of nasal deformities, surgical planning, and surgical reconstruction.

Objectives

To evaluate the feasibility of visualizing nasal cartilage using high resolution micro-computed tomography (CT) compared with the criterion standard of pathologic findings in a cadaveric specimen and to evaluate its accuracy compared with various clinical CT protocols.

Design, Setting, and Participants

Anatomic study at the University of Washington using single human cadaveric nasal specimens performed from July 10, 2017, to March 30, 2018.

Interventions

A micro-CT acquisition with 60-micron resolution was obtained of a nasal specimen. The specimen was then scanned with 5 different clinical CT protocols to span both clinical care and machine limits. The specimen was then sectioned in 5-mm axial slices for pathologic analysis.

Main Outcomes and Measures

Micro-CT images were registered to pathologic specimen cross-sections using a graphite fiducial system. Cartilage substructures were manually segmented and analyzed. A library of matched images across the micro-CT and various clinical CT protocols was then developed. Region of interest analysis was performed for each of the cartilage structures and their boundaries on clinical CT protocols and micro-CT, with the outcome of mean (SD) density using Hounsfield units.

Results

A single human cadaveric nasal specimen was used to obtain the following results. Lower lateral cartilage, upper lateral cartilage, and septal cartilage were accurately delineated on the micro-CT images compared with pathologic findings. The mean absolute deviation from pathologic findings was 0.30 mm for septal cartilage thickness, 0.98 mm for maximal upper lateral cartilage length, and 1.40 mm for maximal lower lateral cartilage length. On clinical CT protocols, only septal cartilage was well discriminated from boundary. Higher radiation dose resulted in more accurate density measurements of cartilage, but it did not ultimately improve ability to discriminate cartilage.

Conclusions and Relevance

The results of this anatomic study may represent a notable step toward advancing knowledge of the capabilities and pitfalls of nasal cartilage visualization on CT. Nasal cartilage visualization was feasible on the micro-CT compared with pathologic findings. Future research may further examine the barriers to accurately visualizing upper lateral cartilage and lower lateral cartilage, a prerequisite for clinical application.

Level of Evidence

NA.

No dynamic extrusion of the medial meniscus in ultrasound examination in patients with confirmed root tear lesion

PURPOSE

Extrusion of the medial meniscus evaluated on magnetic resonance imaging (MRI) has been described as indirect radiological sign for meniscus root tears. However, ultrasound detectable dynamic extrusion is observed in normal physiological settings. The aim of the present study was to analyze the dynamic meniscal extrusion using ultrasound (US) examination in patients with MRI-confirmed meniscal root tears. The hypothesis was that dynamic meniscus extrusion is reduced in patients with medial root tear but not in the healthy meniscus.

METHODS

Twenty-five patients with a medial root lesion of the meniscus (group I) and 25 healthy controls (group II) were enrolled in this study. The medial meniscus extrusion (MME) of the index knee was determined using ultrasound (US) in supine position and under full weight bearing. Standard knee MRI was used for determining whether the patients were eligible for this study according to the inclusion and exclusion criteria, respectively.

RESULTS

In group I, the mean MME was 3.6 mm (± 1.0 mm) in supine position and 3.7 mm (± 0.9 mm) under full weight bearing according to US measurements. The mean Δ-extrusion was 0.1 mm (± 0.2 mm) and the ratio was 1.0 (± 0.1). Mean medial meniscus extrusion on MRI was 3.9 mm (± 0.9 mm). In group II, mean MME was 1.3 mm (± 0.3 mm) in supine position (US) and 2.3 mm (± 0.4 mm) under full weight bearing (US). The mean Δ-extrusion was 1.0 mm (± 0.4 mm) and the extrusion ratio was 1.8 (± 0.4). In this group, mean extrusion in MRI was 1.4 mm (± 0.7 mm). The difference in mean ultrasound Δ-extrusion, ratio, and MRI extrusion between both groups was statistically significant (p < 0.001).

CONCLUSIONS

Based on the results of dynamic ultrasound examination of the medial meniscus, medial root tear leads to significantly decreased dynamic medial displacement of the meniscus compared to healthy meniscus status. The absence of dynamic meniscus extrusion may be an indicator for medial meniscus root injury and could be detected using ultrasound ("dead meniscus sign").

LEVEL OF EVIDENCE

III.

Mountain ultramarathon results in temporary meniscus extrusion in healthy athletes

PURPOSE

In recent literature medial meniscus extrusion (MME) was demonstrated as an age, BMI and load dependent physiological phenomenon in healthy knees. The aim of the present study was to evaluate the influence of mountain ultramarathon running on the medial meniscus extrusion (MME) in healthy athletes.

METHODS

Healthy athletes of the 2017 Gore-Tex® Transalpine run (seven stages with in total 270.5 km and 16453 m altitude) with asymptomatic knee, and no history of knee injuries or surgeries were included. All athletes underwent standard knee examination, MRI to exclude further knee pathologies and ultrasound imaging (USI) for measurement of MME before the competition. Extrusion in USI was determined in supine position (unloaded) and in standing position with full weight bearing and 20° of flexion (loaded). After the 1st, 3rd, and 7th stage ultrasound measurements were repeated directly after the competition. For evaluation of recovery, ultrasound measurement of MME was repeated 2 weeks after the race. Difference between ultrasound measurements of MME was assessed by unpaired t-test with significance set at p < 0.05.

RESULTS

Eighteen athletes (mean age 37.4 ± 8.3 years, 5 females, 13 males) were included in the study. The mean USI MME before the race was 1.9 mm ± 0.3 mm in supine position and 2.4 mm ± 0.4 mm under full weight bearing. During the race the mean MME increased significantly compared to baseline measurements. After 7th stage the mean MME in supine position was 2.7 mm ± 0.7 mm and 3.1 mm ± 0.6 mm under full weight bearing. After 2 weeks of recovery medial meniscus demonstrated a complete reversibility of the extrusion to normal (N.S).

CONCLUSION

Medial meniscus extrusion observed under extreme loads generated by a mountain ultramarathon is a temporary and reversible phenomenon in healthy athletes. This suggests, that the meniscus has viscoelastic capacities showing short-term adaptions to high loads, which are completely reversible over time. For clinical practice assessment of the MME by ultrasound might be favorable compared to MRI due to the ability of dynamic evaluation and the easy access. Furthermore, load should be taken in account when assessing the MME and the current cut-off value of 3 mm for meniscus pathologies should be reconsidered.

LEVEL OF EVIDENCE

IV.

Using only MRI is moderately reliable in the prediction of meniscal tear reparability

PURPOSE

The purpose of this study was to evaluate the role of surgeons' experience with meniscal repairs and meniscectomy decisions, and to determine the factors affecting the disagreement between meniscal repairs and meniscectomy decisions.

METHODS

In total, 223 patients with meniscal tears, 106 meniscal repairs, and 117 meniscectomies were included. Six orthopedic surgeons (3: > 5 years; 3: < 5 years' arthroscopy experience) were blinded, and they independently reviewed all preoperative MR images for over a month. Their reviews were compared with arthroscopic interventions performed by a surgeon with > 10 years' arthroscopy experience. Reparability-associated factors were also evaluated using multivariate logistic regression.

RESULTS

The first and second evaluation results did not differ significantly between groups (n.s.). There was good agreement between MRI predictions and arthroscopic interventions for both groups (< 5 years' experience: k = 0.248, agreement 62.3%; > 5 years' experience: k = 0.351, agreement 67.3%). Sex, side, and distance of tear from the meniscocapsular junction were not significantly different between agreements and disagreements. Disagreement regarding meniscectomy was significantly higher than those regarding meniscus repair (p = 0.002). Concomitant anterior cruciate ligament (ACL) injury, osteochondral lesions, and medial meniscal tear increased the likelihood of meniscal repair (p = 0.0063, p = 0.0010, and p = 0.0369, respectively). An increased risk of disagreement between MRI and surgical procedure was found in the presence of bucket-handle, horizontal or complex tear, chronic tear, high sports activity and expectation level.

CONCLUSION

Surgeon's experience level may influence the prediction of meniscus reparability. Concomitant ACL injury, osteochondral lesions, and presence of medial meniscal tear increase the likelihood of meniscal repair. Tear type, tear chronicity, patient's activity and expectation level may influence the surgeon's operative decision in addition to MRI.

LEVEL OF EVIDENCE

III.

Evaluation of Chondrocalcinosis and Associated Knee Joint Degeneration Using MR Imaging: Data from the Osteoarthritis Initiative

OBJECTIVES

To evaluate the ability of different MRI sequences to detect chondrocalcinosis within knee cartilage and menisci, and to analyze the association with joint degeneration.

METHODS

Subjects with radiographic knee chondrocalcinosis (n = 90, age 67.7 ± 7.3 years, 50 women) were selected from the Osteoarthritis Initiative and matched to controls without radiographic chondrocalcinosis (n = 90). Visualization of calcium-containing crystals (CaC) was compared between 3D T1-weighted gradient-echo (T1GE), 3D dual echo steady-state (DESS), 2D intermediate-weighted (IW), and proton density (PD)-weighted fast spin-echo (FSE) sequences obtained with 3T MRI and correlated with a semiquantitative CaC score obtained from radiographs. Structural abnormalities were assessed using Whole-Organ MRI Score (WORMS) and logistic regression models were used to compare cartilage compartments with and without CaC.

RESULTS

Correlations between CaC counts of MRI sequences and degree of radiographic calcifications were highest for GE (r_T1GE = 0.73, P < 0.001; r_DESS = 0.68, P < 0.001) compared to other sequences (P > 0.05). Meniscus WORMS was significantly higher in subjects with chondrocalcinosis compared to controls (P = 0.005). Cartilage defects were significantly more frequent in compartments with CaC than without (patella: P = 0.006; lateral tibia: P < 0.001; lateral femur condyle: P = 0.017).

CONCLUSIONS

Gradient-echo sequences were most useful for the detection of chondrocalcinosis and presence of CaC was associated with higher prevalence of cartilage and meniscal damage.

KEY POINTS

• Magnetic resonance imaging is useful for assessing burden of calcium-containing crystals (CaC). • Gradient-echo sequences are superior to fast spin echo sequences for CaC imaging. • Presence of CaC is associated with meniscus and cartilage degradation.