Mean Cartilage Thickness Research Articles

High-resolution magnetic resonance imaging can predict osteoarthritic progression after medial meniscus posterior root injury: randomized in vivo experimental study in a rabbit model

ImportanceThe field of meniscal root preservation has undergone significant advancement over the past decades; however, the challenge remains to fully understand whether meniscal root repair can ultimately arrest or delay osteoarthritic changes. ObjectiveTo assess longitudinal changes in articular cartilage, subchondral bone, and progression to meniscal extrusion (ME) using high-resolution magnetic resonance imaging (MRI). MethodsMedial meniscus posterior root tear was surgically induced in 39 New Zealand white rabbits. Animals were randomly assigned into three experimental groups: partial meniscectomy after root tear (PM, n ​= ​13); root tear left in situ (CT, n ​= ​13); and transtibial root repair (RR, n ​= ​13). Contralateral limbs were used as healthy controls. High resolution 4.7 Tesla MRI of the knee joint was performed at baseline, after 2-, and 4-months of post-surgery. Cartilage thickness was calculated in medial and lateral compartments. In addition, the evaluation of ME, subchondral bone edema and healing potential after root repair were assessed too. ResultsProgressive cartilage thinning, ME, and subchondral bone edema were evident in all 3 study groups after 4-months of follow-up. The mean cartilage thickness in the PM group was 0.53 ​mm (±0.050), 0.57 ​mm (±0.05) in the CT group, and 0.60 ​mm (±0.08) in the RR group. The PM group exhibited significantly higher cartilage loss when compared to the CT and RR groups (p ​< ​0.001). Moreover, progressive ME and subchondral bone edema were associated with a more severe cartilage loss at the final follow-up. ConclusionMeniscal root repair did not halt but rather reduced the progression of osteoarthritis (OA). Degenerative changes worsened at a rapid rate in the PM group compared to the RR and CT groups. Early cartilage swelling, persistent subchondral edema, and progressive ME predicted a more severe progression to knee OA in the CT and RR groups. Level of evidenceII.

Three-Dimensional Quantitative Magnetic Resonance Imaging Cartilage Evaluation of the Hand Joints of Systemic Sclerosis Patients: A Novel Insight on Hand Osteoarthritis Pathogenesis—Preliminary Report

Background. Osteoarthritis of the hand joints in systemic sclerosis (SSc) patients might be an independent manifestation leading to limitation of upper extremity function. There is no publication quantitatively assessing the thickness of articular cartilage within the hand joints of SSc patients by MRI. The purpose of our study was to quantify the condition and thickness of hand joints cartilage with three-dimensional quantitative MRI (3D q-MRI). Methods. The study was conducted in twenty people: ten patients with SSc and ten healthy individuals. All participants were examined with the 3D q-MRI with 3T scanner. The cartilage thickness of proximal (PIP) and distal interphalangeal (DIP) joints as well as metacarpophalangeal joints was measured. Results. There was no significant difference in cartilage thickness between both groups. However, the joint cartilage was thinner in fingers with acro-osteolysis. In PIP joint of the fingers with acro-osteolysis, the mean cartilage thickness was 0.5 mm (p = 0.0043) and 0.4 mm (p = 0.0034) in DIP joints. Conclusions. Quantitative MRI analysis of the joints of the hands of SSc patients does not indicate changes in thickness of the articular cartilage. A significant reduction in the articular cartilage thickness of the fingers with acro-osteolysis indicates the potential of an ischemic basis of articular cartilage destruction in SSc patients.

Quantification of cartilage and subchondral bone cysts on knee specimens based on a spectral photon-counting computed tomography

Spectral photon-counting computed tomography (SPCCT) is a new technique with the capability to provide mono-energetic (monoE) images with high signal to noise ratio. We demonstrate the feasibility of SPCCT to characterize at the same time cartilage and subchondral bone cysts (SBCs) without contrast agent in osteoarthritis (OA). To achieve this goal, 10 human knee specimens (6 normal and 4 with OA) were imaged with a clinical prototype SPCCT. The monoE images at 60 keV with isotropic voxels of 250 × 250 × 250 µm3 were compared with monoE synchrotron radiation CT (SR micro-CT) images at 55 keV with isotropic voxels of 45 × 45 × 45 µm3 used as benchmark for cartilage segmentation. In the two OA knees with SBCs, the volume and density of SBCs were evaluated in SPCCT images. In 25 compartments (lateral tibial (LT), medial tibial, (MT), lateral femoral (LF), medial femoral and patella), the mean bias between SPCCT and SR micro-CT analyses were 101 ± 272 mm3 for cartilage volume and 0.33 mm ± 0.18 for mean cartilage thickness. Between normal and OA knees, mean cartilage thicknesses were found statistically different (0.005 < p < 0.04) for LT, MT and LF compartments. The 2 OA knees displayed different SBCs profiles in terms of volume, density, and distribution according to size and location. SPCCT with fast acquisitions is able to characterize cartilage morphology and SBCs. SPCCT can be used potentially as a new tool in clinical studies in OA.

Getting Cartilage Thickness Measurements Right: A Systematic Inter-Method Comparison Using MRI Data from the Osteoarthritis Initiative.

Magnetic resonance imaging is the standard imaging modality to assess articular cartilage. As the imaging surrogate of degenerative joint disease, cartilage thickness is commonly quantified after tissue segmentation. In lack of a standard method, this study systematically compared five methods for automatic cartilage thickness measurements across the knee joint and as a function of region and sub-region: 3D mesh normals (3D-MN), 3D nearest neighbors (3D-NN), 3D ray tracing (3D-RT), 2D centerline normals (2D-CN), and 2D surface normals (2D-SN). Based on the manually segmented femoral and tibial cartilage of 507 human knee joints, mean cartilage thickness was computed for the entire femorotibial joint, 4 joint regions, and 20 subregions using these methods. Inter-method comparisons of mean cartilage thickness and computation times were performed by one-way analysis of variance (ANOVA), Bland-Altman analyses and Lin's concordance correlation coefficient (CCC). Mean inter-method differences in cartilage thickness were significant in nearly all subregions (P < 0.001). By trend, mean differences were smallest between 3D-MN and 2D-SN in most (sub)regions, which is also reflected by highest quantitative inter-method agreement and CCCs. 3D-RT was prone to severe overestimation of up to 2.5 mm. 3D-MN, 3D-NN, and 2D-SN required mean processing times of ≤5.3 s per joint and were thus similarly efficient, whereas the time demand of 2D-CN and 3D-RT was much larger at 133 ± 29 and 351 ± 10 s per joint (P < 0.001). In automatic cartilage thickness determination, quantification accuracy and computational burden are largely affected by the underlying method. Mesh and surface normals or nearest neighbor searches should be used because they accurately capture variable geometries while being time-efficient.

CARTILAGE THICKNESS, SUBCHONDRAL BONE MINERAL DENSITY, AND AMBULATORY LOADING ARE CORRELATED IN NON-OSTEOARTHRITIC FEMORAL CONDYLES

A few studies have reported correlations between structural and functional parameters in healthy knees, and sometimes alterations of these correlations with OA. These observations suggested a new concept where knee OA could be related to a maladaptation between joint features. However, studies analyzing multiple features from different domains simultaneously are missing, which makes it difficult to fully understand the importance of relationships in maintaining joint homeostasis and their role in the development of OA. To assess the correlations among cartilage thickness (CTh), subchondral bone mineral density (sBMD), and ambulatory loading in non-OA femoral condyles. As commonly done, ambulatory loading was quantified using the peak knee adduction moment during walking (pKAM), which is a proxy for the distribution of load between medial and lateral compartments. To analyze comparable data, CTh and sBMD were expressed as medial-to-lateral (M/L) ratios. Therefore, this study tested the hypothesis that CTh M/L ratios, sBMD M/L ratios, and pKAM are positively correlated in non-OA femoral condyles. This study analyzed a subgroup of 48 young (25.7 ± 4.8 years; 22 males) asymptomatic volunteers with healthy knees enrolled in the HIPPA-compliant IRB-approved Lausanne Knee Study. This study aims at characterizing the structure and function of the knee, with a particular emphasis on the relationships among knee features The study protocol included clinical evaluation, radiographic imaging (weight-bearing Schuss and lateral radiographs of both knees), CT imaging (calibrated by a solid calcium hydroxyapatite-based bone mineral reference phantom) and 3T MRI of one randomly selected knee. 3D gait recordings were performed using a 16-camera motion capture system and force plates. CTh was obtained by manually segmenting the cartilage and bone on the DESS images, building 3D mesh models of bone and cartilage, and calculating the distance between the models. sBMD was obtained by registering the bone models from the DESS segmentation to the CT images and calculating the average CT intensity in the 3 mm of bone adjacent to cartilage. Mean CTh and sBMD were then calculated for six common regions of interest (ROIs) in the medial and lateral condyles and expressed as M/L ratios. pKAM was obtained following a standard inverse dynamics procedure applied to the marker-based motion capture and force plate recordings. Data processing was done using in-house software and algorithms previously validated. The relationship among CTh M/L ratios, sBMD M/L ratios and pKAM were assessed using Pearson correlation, with an α-level set a priori at 5%. All statistically significant correlations were positive, indicating larger CTh M/L ratios in knees with larger sBMD M/L ratios and larger pKAM, and vice versa. Specifically, CTh and sBMD M/L ratios were correlated in 5 of the 6 ROIs (0.31 ≤ r ≤ 0.53; 0.001 ≤ p ≤ 0.035), CTh M/L ratios in 4 ROIs were correlated with pKAM (0.29 ≤ r ≤ 0.33; 0.021 ≤ p ≤ 0.047), and sBMD M/L ratio in one ROI was correlated with pKAM (r = 0.31; p = 0.032). The hypothesis was supported, confirming the idea that structural and mechanical features of the knee are positively correlated, or adapted, in non-OA knees. This first study to show correlations among bone, cartilage, and mechanical loading provided insight into the functioning of the joint and underlined the potential of evaluating knee health based on relationships among features rather than on individual features in isolation. The analyses in this study will be extended to OA knees in future studies in order to determine the alterations of the relationships between knee features with OA.

Effects of Intra-articular Platelet Rich Plasma on Cartilage Thickness, Clinical and Functional Outcomes in Knee Osteoarthritis.

Osteoarthritis of the kneeis one of the most common degenerative diseases and the fourth leading cause of years lived with disability at the global level. This study assessed the efficacy of platelet-rich plasma (PRP) in osteoarthritis of knees as to changes in cartilage thickness and clinical and functional outcomes. Thirty participants with Kellgren-Lawrence grade two and grade three osteoarthritis knee who satisfied the inclusion and exclusion criteria were enrolled in this prospective interventional study after taking written informed consent. Each participant received three doses of two ml intraarticular platelet-rich plasma at an interval of seven days. Clinical assessment was determined using the Visual Analogue Scale (VAS) and Knee Osteoarthritis Outcome Score (KOOS) on Day 0, Day 90, and Day 180. Cartilage thickness (femoral and trochlear cartilage) was measured pre (Day 0) and post-PRP (Day 180) under ultrasound guidance. The mean VAS score for pain was 7.4 before treatment which changed to 5.3 (p= <0.0001) on Day 90 and 3.37 (p= <0.0001) on Day 180 post-PRP. The mean total KOOS was 19.16 ± 10.73 before treatment which improved to 37.42 ± 9.88 (p= <0.0001) and 49.98 ± 8.82 (p= <0.0001) at 90 days, and 180 days post-injection, respectively. The mean cartilage thickness (femoral and trochlear cartilage) improved from baseline (day 0) to final follow-up on day 180, which was statistically significant and implied cartilage repair following PRP administration. This study supports the efficacy of PRP in the management of osteoarthritis knee by improvement in pain, joint stiffness, and activities of daily living, as well as aids in the repair and regeneration of articular cartilage.

Test–retest precision and longitudinal cartilage thickness loss in the IMI-APPROACH cohort

To investigate the test-retest precision and to report the longitudinal change in cartilage thickness, the percentage of knees with progression and the predictive value of the machine-learning-estimated structural progression score (s-score) for cartilage thickness loss in the IMI-APPROACH cohort - an exploratory, 5-center, 2-year prospective follow-up cohort. Quantitative cartilage morphology at baseline and at least one follow-up visit was available for 270 of the 297 IMI-APPROACH participants (78% females, age: 66.4±7.1 years, body mass index (BMI): 28.1±5.3kg/m2, 55% with radiographic knee osteoarthritis (OA)) from 1.5T or 3T MRI. Test-retest precision (root mean square coefficient of variation) was assessed from 34 participants. To define progressor knees, smallest detectable change (SDC) thresholds were computed from 11 participants with longitudinal test-retest scans. Binary logistic regression was used to evaluate the odds of progression in femorotibial cartilage thickness (threshold:-211μm) for the quartile with the highest vs the quartile with the lowest s-scores. The test-retest precision was 69μm for the entire femorotibial joint. Over 24 months, mean cartilage thickness loss in the entire femorotibial joint reached-174μm (95% CI: [-207,-141]μm, 32.7% with progression). The s-score was not associated with 24-month progression rates by MRI (OR: 1.30, 95% CI: [0.52, 3.28]). IMI-APPROACH successfully enrolled participants with substantial cartilage thickness loss, although the machine-learning-estimated s-score was not observed to be predictive of cartilage thickness loss. IMI-APPROACH data will be used in subsequent analyses to evaluate the impact of clinical, imaging, biomechanical and biochemical biomarkers on cartilage thickness loss and to refine the machine-learning-based s-score. NCT03883568.

Hyaluronic Acid Dermal Filler Promotes Cartilage Reshaping in Rabbit Ears.

Neonatal ear is more malleable and soft, allowing the correction of deformities by using external molding. This is mainly attributed to high concentration of the proteoglycan aggregate and hyaluronic acid. In this study, HA dermal filler was injected in rabbit ear as a long acting HA source to investigate the biological impact of HA in reshaping the ear cartilage. Ears of twelve rabbits were divided into 4 groups. Control group was the left ears of 6 animals which were left intact. Group 2 was the right ears of the same animals, which received saline solution injection. Group 3 was the left ears of the other 6 animals, which were given 1 mL of HA. Group 4 was the right ears of them, which were given 2 mL of HA in both sites of the ear. All ears were folded and splinted for 4 weeks. Then, the angle of each ear was calculated. Following an additional 4 weeks, a cartilage biopsy was taken for histological examination. The ear angles did not show any statistical difference at week 4. There was a significant difference among the groups at the 8th week. In the 3rd and 4th groups, mean angles were higher than the group 1 and group 2. Thickening in the cartilage and ectopic cartilage formation was observed in the contact areas to hyaluronic acid. Significant difference was also found between the peak and mean cartilage thicknesses. HA dermal filler can stimulate cartilage regeneration by increasing the synthesis of extracellular matrix and chondrogenesis especially where it is in direct contact with the ear cartilage. This journal requires that authors assign a level of evidence to each submission to which Evidence-Based Medicine rankings are applicable. This excludes Review Articles, Book Reviews, and manuscripts that concern Basic Science, Animal Studies, Cadaver Studies, and Experimental Studies. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Accessibility and Thickness of Medial and Lateral Talar Body Cartilage for Treatment of Ankle and Foot Osteochondral Lesions.

The purposes of this study were to determine (1) if cartilage thicknesses on the talar dome and medial/lateral surfaces of the talus were similar, (2) whether there was sufficient donor cartilage surface area on the medial and lateral talar surfaces to repair talar dome cartilage injuries of the talus, and (3) whether the cartilage surface could be increased following anterior talofibular ligament (ATFL) and sectioning of the tibionavicular and tibiospring portion of the anterior deltoid. Medial and lateral approaches were utilized in 8 cadaveric ankles to identify the accessible medial, lateral, and talar dome cartilage surfaces in 3 conditions: (1) intact, (2) ATFL release, and (3) superficial anterior deltoid ligament release. The talus was explanted, and the cartilage areas were digitized with a coordinate measuring machine. Cartilage thickness was quantified using a laser scanner. The mean cartilage thickness was 1.0 ± 0.1 mm in all areas tested. In intact ankles, the medial side of the talus showed a larger total area of available cartilage than the lateral side (152 mm2 vs 133 mm2). ATFL release increased the available cartilage area on the medial and lateral sides to 167 mm2 and 194 mm2, respectively. However, only the lateral talar surface had sufficient circular graft donor cartilage available for autologous osteochondral transplantation (AOT) procedures of the talus. After ATFL and deltoid sectioning, there was an increase in available graft donor cartilage available for AOT procedures. The thickness of the medial and lateral talar cartilage surfaces is very similar to that of the talar dome cartilage surface, which provides evidence that the medial and lateral surfaces may serve as acceptable AOT donor cartilage. The surface area available for AOT donor site grafting was sufficient in the intact state; however, sectioning the ATFL and superficial anterior deltoid ligament increased the overall lateral talar surface area available for circular grafting for an AOT procedure that requires a larger graft. These results support the idea that lateral surfaces of the talus may be used as donor cartilage for an AOT procedure since donor and recipient sites are similar in cartilage thickness, and there is sufficient cartilage surface area available for common lesion sizes in the foot and ankle. This anatomical study investigates the feasibility of talar osteochondral autografts from the medial or lateral talar surfaces exposed with standard approaches. It confirms the similar cartilage thickness of the talar dome and the ability to access up to an 8- to 10-mm donor graft from the lateral side of the talus after ligament release. This knowledge may allow better operative planning for use of these surfaces for osteochondral lesions within the foot and ankle, particularly in certain circumstances of a revision microfracture.

3D contour registration reveals that location-independent cartilage thickness scores and regional patterns differ between early and late follow-up periods after anterior cruciate ligament (ACL) rupture

Purpose: Anterior cruciate ligament (ACL) rupture is associated with acute joint trauma, chronically altered joint mechanics; and subsequently with an increased risk of incident knee osteoarthritis (OA). It has been reported that the mean femorotibial cartilage thickness increases in young adults after ACL rupture, with the annual rate during the first 2 years (BL→Y2) being similar to that during the subsequent 3 years (Y2→Y5). Previous work has shown that this mean cartilage thickness change does not reflect simultaneous thinning and thickening that occurred in different subregions of the joint, and that simultaneous thinning and thickening actually differed in magnitude between the first and later observation period, independent of treatment.

Patterns of Articular Cartilage Thickness in Pediatric and Adolescent Knees: A Magnetic Resonance Imaging–Based Study

PurposeTo establish normative values for articular cartilage thickness in pediatric and adolescent knees using magnetic resonance imaging (MRI) and investigate for any associations with age and skeletal maturity.MethodsMRI scans were analyzed in patients 7 to 18 years old without osteochondral lesions, chondral wear/pathology, intra-articular fractures, or history of knee surgery. Measurements of articular cartilage thickness at the patella (medial facet, lateral facet, median ridge), femur (medial condyle, lateral condyle, lateral trochlea), and tibia (medial plateau, lateral plateau) were made on axial, coronal, and sagittal MRI. Descriptive statistics were used to calculate mean cartilage thickness by age and sex. Analysis of variance with repeated measures, analysis of covariance, independent samples t test, and linear regression were performed to determine differences in mean cartilage thickness by anatomic location, sex, physeal status, and age, respectively.ResultsA total of 240 knee MRI scans were included. Articular cartilage was thickest at the patella and did not vary with age or skeletal maturity. On the femur, articular cartilage was thickest at the lateral trochlea with mean cartilage thickness of 4.4 ± 1.4 mm in male patients and 3.6 ± 1.3 mm in female patients (P < .001). Patients with open distal femoral physes had significantly thicker cartilage at the medial femoral condyle, lateral femoral condyle, and lateral trochlea compared to patients with closing/closed physes (P < .001). Linear regression analysis revealed a significant inverse association between cartilage thickness at the femur and age.ConclusionsIn pediatric and adolescent knees, articular cartilage is thickest at the patella, where it does not strongly correlate with age. In contrast, there is a strong inverse association between increasing age and articular cartilage thickness of the distal femoral condyles.Clinical RelevanceThe longitudinal reference data presented in this study can aid in pre-operative interpretation of knee cartilage under pathologic conditions in pediatric and adolescent patients.

Comparison between 2D radiographic weight-bearing joint space width and 3D MRI non-weight-bearing cartilage thickness measures in the knee using non-weight-bearing 2D and 3D CT as an intermediary.

Background:In knee osteoarthritis, radiographic joint space width (JSW) is frequently used as a surrogate marker for cartilage thickness; however, longitudinal changes in radiographic JSW have shown poor correlations with those of magnetic resonance imaging (MRI) cartilage thickness. There are fundamental differences between the techniques: radiographic JSW represents two-dimensional (2D), weight-bearing, bone-to-bone distance, while on MRI three-dimensional (3D) non-weight-bearing cartilage thickness is measured. In this exploratory study, computed tomography (CT) was included as a third technique, as it can measure bone-to-bone under non-weight-bearing conditions. The objective was to use CT to compare the impact of weight-bearing versus non-weight-bearing, as well as bone-to-bone JSW versus actual cartilage thickness, in the knee.Methods:Osteoarthritis patients (n = 20) who were treated with knee joint distraction were included. Weight-bearing radiographs, non-weight-bearing MRIs and CTs were acquired before and 2 years after treatment. The mean radiographic JSW and cartilage thickness of the most affected compartment were measured. From CT, the 3D median JSW was calculated and a 2D projectional image was rendered, positioned similarly and measured identically to the radiograph. Pearson correlations between the techniques were derived, both cross-sectionally and longitudinally.Results:Fourteen patients could be analyzed. Cross-sectionally, all comparisons showed moderate to strong significant correlations (R = 0.43–0.81; all p < 0.05). Longitudinal changes over time were small; only the correlations between 2D CT and 3D CT (R = 0.65; p = 0.01) and 3D CT and MRI (R = 0.62; p = 0.02) were statistically significant.Conclusion:The poor correlation between changes in radiographic JSW and MRI cartilage thickness appears primarily to result from the difference in weight-bearing, and less so from measuring bone-to-bone distance versus cartilage thickness.

Potential influence from lower limb preference and 1-RM on cartilage thickness

PurposeThe aims of this study were to assess the potential retrospective relationship between limb preference and cartilage thickness, and to determine the association between measures of strength using 1-RM tests and cartilage thickness.MethodsCross-sectional retrospective design was employed. Limb preference and injury history were collected using the Waterloo Inventory followed by femoral cartilage imaging using ultrasound. 15 apparently healthy participants (11 males and four females) without musculoskeletal or neurological diseases volunteered for the study. After collection of anthropometric measures, warm-up and familiarization, participants performed 1-RM for back half-squat on a Smith machine. Ultrasound images were digitized to determine bilateral differences and femoral cartilage thickness.ResultsSignificant moderate association between the existence of a prior injury and bilateral differences in cartilage thickness (&lt;i&gt;r&lt;/i&gt; = -0.63, &lt;i&gt;p&lt;/i&gt; &lt; 0.01), in favor of the preferred limb was observed. Significant moderate association between the 1-RM, as percentage of body mass, and the mean cartilage thickness between limb (&lt;i&gt;r&lt;/i&gt; = 0.58, &lt;i&gt;p&lt;/i&gt; = 0.049).ConclusionsBilateral differences in cartilage thickness are not associated with limb preference but depend on the history of lower limb injuries. The relative load lifted during a 1-RM half-squat is associated with thicker femoral cartilages, which suggests that relative strength is an important measure of cartilage health.

FRI0417 IDENTIFICATION OF THE MOST IMPORTANT FEATURES OF KNEE OSTEOARTHRITIS PROGRESSORS USING MACHINE LEARNING METHODS

Background:Knee osteoarthritis (OA), a leading cause of disability worldwide, can be difficult to define as its development is often insidious and involves different subgroups. We still lack robust prediction models that are able to guide clinical decisions and stratify OA patients according to risk of disease progression.Objectives:This study aimed at identifying the most important features of knee OA progressors. To this end, we used machine learning (ML) algorithms on a large set of subjects and features to develop advanced prediction models that provide high classification and prediction performance.Methods:Participants, features and outcomes were from the Osteoarthritis Initiative. Features were from baseline (1107), including articular knee tissues (135) assessed by quantitative MRI. OA progressors were ascertained by four outcomes: cartilage volume loss in medial plateau at 48 and 96 months (Prop_CV_48M, 96M); Kellgren-Lawrence (KL) grade ≥2; and medial joint space narrowing (JSN) ≥1 at 48 months. Subjects’ numbers were as follows: 1598 for the outcome Prop_CV_96M, 1044 for the Prop_CV_48M, and 1468 for each KL grade ≥2 at 48 months and JSN ≥1 at 48 months. Six feature selection models were used to identify the common features in each outcome. Six classification methods were applied to measure the accuracy of the selected features in classifying the subjects into progressors and non-progressors. Classification of the best features was done using auto-ML interface and the area under the curve (AUC). To prioritize the top features, Sparse Partial Least Square (sPLS) method was used.Results:For the classification of the best common features in each outcome, Multi-Layer Perceptron (MLP) achieved the highest AUC in Prop_CV_96M, KL, and JSN (0.80, 0.88, 0.95), and Gradient Boosting Machine (GBM) for Prop_CV_48M (0.70). sPLS revealed that the baseline top five features to predict knee OA progressors are the joint space width (JSW), mean cartilage thickness of peripheral, medial, and central tibial plateau, and JSN.Conclusion:This is the first time that such a comprehensive study was performed for identifying the best features and classification methods for knee OA progressors. Data revealed that early prediction of knee OA progression can be done with high accuracy and based on only a few features. This study identifies the baseline X-ray and MRI-based features as the most important for predicting knee OA progressors. These results could be used for the development of a tool enabling prediction of knee OA progressors.Acknowledgments:This work was supported in part by the Osteoarthritis Research Unit of the University of Montreal Hospital Research Centre; the Chair in Osteoarthritis, University of Montreal, (both from Montreal, Quebec, Canada); and the Computational Biology Laboratory, Laval University Hospital Research Center, (Québec, Quebec, Canada). A Jamshidi received a bursary from the Canada First Research Excellence Fund through TransMedTech Institute, (Montreal, Quebec, Canada).Disclosure of Interests:Afshin Jamshidi: None declared, Mickaël Leclercq: None declared, Aurelie Labbe: None declared, Jean-Pierre Pelletier Shareholder of: ArthroLab Inc., Grant/research support from: TRB Chemedica, Speakers bureau: TRB Chemedica and Mylan, François Abram Employee of: ArthroLab Inc., Arnaud Droit: None declared, Johanne Martel-Pelletier Shareholder of: ArthroLab Inc., Grant/research support from: TRB Chemedica

Measuring of knee cartilage thickness: A comparison between ultrasound and magnetic resonance imaging methods

Cartilage diameter evaluation is critical for cartilage assessment. Magnetic resonance imaging (MRI) is the gold standard toolin cartilage evaluation. This observational and analytical study was designed to answer the question of whether there is arelationship between MRI and ultrasound in measuring cartilage thickness in the medial femoral condyle. The current study wasconducted at the Radiology Department of Rasole-Akram Hospital, Tehran, Iran, between March and May 2020. The samplesize was 18 people. The mean cartilage thickness of the left medial femoral cartilage was measured by T1 weighted MRI andultrasound from transverse, anterior, middle, and posterior medial femoral regions in nine healthy females with a mean ± stddeviation as indicated below: thickness = 1.6 ± 0.04 m, weight = 55.3 ± 4.3 kg, age = 21.7 ± 0.8 years.Additionally, nine healthy males with thickness = 1.80 ± 0.02 m, weight = 78.6 ± 11.1 kg, age = 22.4 ± 0.7 years were alsoincluded. Pearson and Bland–Altman plots were used for correlations and agreements. Anterior longitudinal ultrasoundthickness measures were significantly positively correlated with MRI anterior (r = 0.93, p = 0.00001), transverse ultrasoundwith MRI anterior (r = 0.87 p = 0.0369), middle longitudinal ultrasound with MRI anterior (r = 0.87 p = 0.00002), and transverseultrasound and MRI middle (r = 0.87 p = 0.00001).Agreement in all aspects was good except between the anterior longitudinal ultrasound and MRI posterior. There was a goodabsolute agreement between corresponding measurements done by ultrasound and MRI. The results suggest that ultrasound maybe a good clinical tool for assessing relative cartilage thickness in medial femoral regions.

Accessory anterolateral talar facet: analysis of the morphologic features on MRI.

To analyze the morphologic features of accessory anterolateral talar facet (AALTF) on MRI that can assist in detecting this entity, identify any associated structural changes and also define its MRI prevalence. Two radiologists retrospectively evaluated 140 ankle MRI scans for the presence of AALTF, complimentary anterior calcaneal extension facet and angle of Gissane measurement. One observer evaluated the scans for other structural details including AALTF length, cartilage thickness, bone marrow edema, hind foot coalition and talar beaking. There was a good inter-observer agreement for the detection of AALTF on MRI (Kappa = 0.64). AALTF was present in 33 out of 140 (23.6%) scans. There was no significant difference in the prevalence of AALTF between male and female subjects (P = 0.71). No significant difference in age between those with and those without AALTF (P = 0.96). Angle of Gissane was significantly smaller in ankles with AALTF (P = 0.0367, observer 1 and 0.0003, observer 2). AALTF had a mean length of 7mm and was covered with cartilage in 25/33 (75.8%) with mean cartilage thickness of 1.4mm. Complimentary cartilage covered anterior calcaneal facet was demonstrated in 10/33 (30.3%) and had a mean cartilage thickness of 2.5mm. Talar beaking was more prevalent in ankles with AALTF showing an anterior calcaneal extension facet than those without the latter feature (P = 0.02). AALTF is a frequently observed feature on ankle MRI, with good inter-observer reliability for its detection. When present, it is often opposed by a cartilage covered anterior calcaneal extension facet, which can be associated with talar beaking.

The effect of recurrent malaria infections on bone and cartilage at the distal femoral epiphysis of rats: A histological study

Objective: The aim of this study was to investigate the normal changes that occur at the distal femoral epiphysis of rats and determine whether recurrent bouts of malaria altered them in anyway. Materials and Methods: The 1st phase of the study made use of 30 Sprague-Dawley rats aged 4 weeks. Two rats were culled each week for 15 weeks, the femoral bones of the rats were then harvested. Histological sections of the distal femora were prepared and studied. The 2nd phase involved 32 animals that were randomly assigned to four groups of 8 animals each. (Group A to D) Group A was given oral antimalarial drugs only, Group B was inoculated with Plasmodium berghei (NK65) only, Group C was inoculated with P. berghei (NK65) and treated with oral antimalarial drug, and Group D animals were neither inoculated nor given antimalarial drugs. At the end of the experiment histological sections of the femoral epiphysis of the rats were prepared and studied. Results: The microscopic architecture of the epiphyseal cartilage changed significantly as the animals aged. Significant differences were observed in mean bone thickness of the various experimental groups. There was however no significant difference in the mean cartilage thickness when comparison was made within the various groups. Conclusion: Although recurrent bouts of malaria infection appear not to alter the normal histological changes that occur in epiphyseal bone and cartilage layers, it most likely has an adverse effect on the rate of bone tissue deposition.

Identification of the most important features of knee osteoarthritis structural progressors using machine learning methods.

Objectives:The aim was to identify the most important features of structural knee osteoarthritis (OA) progressors and classification using machine learning methods.Methods:Participants, features and outcomes were from the Osteoarthritis Initiative. Features were from baseline (1107), including articular knee tissues (135) assessed by quantitative magnetic resonance imaging (MRI). OA progressors were ascertained by four outcomes: cartilage volume loss in medial plateau at 48 and 96 months (Prop_CV_48M, 96M), Kellgren–Lawrence (KL) grade ⩾ 2 and medial joint space narrowing (JSN) ⩾ 1 at 48 months. Six feature selection models were used to identify the common features in each outcome. Six classification methods were applied to measure the accuracy of the selected features in classifying the subjects into progressors and non-progressors. Classification of the best features was done using an automatic machine learning interface and the area under the curve (AUC). To prioritize the top five features, sparse partial least square (sPLS) method was used.Results:For the classification of the best common features in each outcome, Multi-Layer Perceptron (MLP) achieved the highest AUC in Prop_CV_96M, KL and JSN (0.80, 0.88, 0.95), and Gradient Boosting Machine for Prop_CV_48M (0.70). sPLS showed the baseline top five features to predict knee OA progressors are the joint space width, mean cartilage thickness of the medial tibial plateau and sub-regions and JSN.Conclusion:In this comprehensive study using a large number of features (n = 1107) and MRI outcomes in addition to radiological outcomes, we identified the best features and classification methods for knee OA structural progressors. Data revealed baseline X-ray and MRI-based features could predict early OA knee progressors and that MLP is the best classification method.

Histologic Analysis of 2 Alternative Donor Sites of the Ipsilateral Elbow in the Treatment of Capitellar Osteochondritis Dissecans

To compare the histologic features of the cartilage from the capitellum with 2 proposed alternative donor sites from the ipsilateral elbow in the treatment of capitellar osteochondritis dissecans (OCD): the nonarticulating part of the radial head and the nonarticulating lateral side of the olecranon tip. Ten human cadaveric elbow specimens with macroscopically normal articular surfaces were used to obtain 5-mm osteochondral grafts: 10 from the capitellum (60° anteriorly relative to the humeral shaft), 10 from the radial head (nonarticulating part at 80°), and 4 from the olecranon (lateral side of the olecranon tip). Grafts were fixated in formalin (4% formaldehyde), decalcified, and processed into standard 8-μm-thick hematoxylin and eosin-and Toluidine Blue-stained sections. These were assessed for cartilage thickness, shape of articular surface, and 13 histologic parameters of the International Cartilage Repair Society II. Olecranon scores were excluded from statistical analysis. Mean cartilage thickness was 1.5 ± 0.22mm at the capitellum; 1.3 ± 0.34mm at the radial head; and 1.9 ± 1.0mm at the olecranon. There was no difference in cartilage thickness between the capitellum and radial head (P= .062). All grafts demonstrated a convex articular surface. International Cartilage Repair Society II scores ranged from 82 to 100 for the capitellum, from 81 to 100 for the radial head, and from 67 to 87 for the olecranon tip. There was less chondrocyte clustering at the capitellum (84 ± 14) than in the radial head (94 ± 3.2; P= .019). Mid/deep zone assessment of the capitellum scored higher (97 ± 6.7) than the radial head (91 ± 4.6; P= .038). This study demonstrates appropriate histologic similarities between the cartilage from the capitellum and 2 alternative donor sites of the ipsilateral elbow in the treatment of capitellar OCD: the nonarticulating part of the radial head and the nonarticulating lateral side of the olecranon tip. From an histologic point of view, there seem to be no obstacles to use grafts from these alternative donor sites for reconstruction of the capitellum when performing osteochondral autologous transplantation.

Ultrasound detected changes in joint cartilage thickness in juvenile idiopathic arthritis.

The purpose of this study was to investigate the changes in joint cartilage thickness in different subtypes of juvenile idiopathic arthritis (JIA) using ultrasound, comparing them with healthy children and to evaluate the relationship with disease duration and inflammatory markers. We conducted a cross-sectional study comprising of 27 cases of JIA and 54 age- and sex-matched healthy children. Bilateral wrist, knee and ankle joint cartilage thicknesses were measured by ultrasound as per European League Against Rheumatism standard guidelines and compared them between JIA subtypes as well as between cases and control. Descriptive analysis of the whole cohort revealed the mean age of the study population was 8.3±3.2years with mean cartilage thicknesses at the wrist, knee and ankle being 1.40±0.89mm, 1.57±0.78mm and 1.41±0.85mm, respectively. The median cartilage thicknesses of wrist, knee and ankle joints of JIA cases (n=27) and healthy controls (n=54) were 1.01, 1.35, 1.05 and 1.95, 2.00, 1.95, respectively. The joint cartilage thickness was significantly reduced in JIA in comparison to the healthy cohort (P<0.01). Diseased boys suffered greater cartilage damage in knee joints compared to girls; the polyarticular variety of cases had thinner knee cartilage in comparison to the oligoarticular subtype. Further, it was found that joint cartilage destruction is independent of inflammatory markers and disease duration. Significant cartilage thinningin addition was found in JIA children, particularly in the polyarticular subtype, and morein boys than girls, which is independent of disease duration and inflammatory markers, using ultrasound as a primary investigative tool.