Cartilage Thickness Measurements Research Articles

The Correlation between Ultrasonographic Measurements of Femoral Cartilage Thickness and Physical Function in patients with primary knee osteoarthritis

The Correlation between Ultrasonographic Measurements of Femoral Cartilage Thickness and Physical Function in patients with primary knee osteoarthritis

Variations in knee cartilage thickness: Fully automatic three-dimensional analysis of MRIs from five manufacturers

BackgroundMeasurements of knee cartilage thickness derived from MR images are attractive biomarkers for osteoarthritis research. Although some cross-sectional multivendor studies exist, none have employed fully automatic three-dimensional MRI analysis. Our objective was to evaluate the variations in knee cartilage thickness measurements obtained using automated methods and MRI instruments from five different vendors. MethodsThe subjects were 10 healthy volunteers aged 22–60 years. MRI models with 3 Tesla strength from five different companies were used. Cartilage thickness was quantified fully automatically for seven regions. We hypothesized that “the MRI model influences cartilage thickness measurements.” Inter-measurement error, defined as the absolute difference between the targeted and median thicknesses determined by the five MRI models, was analyzed using histograms. The factors generating the largest inter-measurement error were also examined. ResultsNo exceptional trends attributable to a specific instrument model were observed, and the p-value from the Kruskal–Wallis test exceeded 0.05 in all seven regions. Therefore, the study hypothesis was rejected. Of the 350 measurements, the inter-measurement error was ≤0.05 mm in 53 %, ≤0.10 mm in 75 %, and ≤0.20 mm in 95 %. Analysis of the medial tibial cartilage, which had the largest inter-measurement error, revealed mis-extraction of synovial fluid as cartilage. ConclusionsThe choice of MRI model did not influence cartilage thickness measurements. Overall, 95 % of the inter-measurement errors were within 0.20 mm. The greatest error resulted from mis-extracting synovial fluid as cartilage.

Automated measurement and grading of knee cartilage thickness: a deep learning-based approach.

Knee cartilage is the most crucial structure in the knee, and the reduction of cartilage thickness is a significant factor in the occurrence and development of osteoarthritis. Measuring cartilage thickness allows for a more accurate assessment of cartilage wear, but this process is relatively time-consuming. Our objectives encompass using various DL methods to segment knee cartilage from MRIs taken with different equipment and parameters, building a DL-based model for measuring and grading knee cartilage, and establishing a standardized database of knee cartilage thickness. In this retrospective study, we selected a mixed knee MRI dataset consisting of 700 cases from four datasets with varying cartilage thickness. We employed four convolutional neural networks-UNet, UNet++, ResUNet, and TransUNet-to train and segment the mixed dataset, leveraging an extensive array of labeled data for effective supervised learning. Subsequently, we measured and graded the thickness of knee cartilage in 12 regions. Finally, a standard knee cartilage thickness dataset was established using 291 cases with ages ranging from 20 to 45 years and a Kellgren-Lawrence grading of 0. The validation results of network segmentation showed that TransUNet performed the best in the mixed dataset, with an overall dice similarity coefficient of 0.813 and an Intersection over Union of 0.692. The model's mean absolute percentage error for automatic measurement and grading after segmentation was 0.831. The experiment also yielded standard knee cartilage thickness, with an average thickness of 1.98 mm for the femoral cartilage and 2.14 mm for the tibial cartilage. By selecting the best knee cartilage segmentation network, we built a model with a stronger generalization ability to automatically segment, measure, and grade cartilage thickness. This model can assist surgeons in more accurately and efficiently diagnosing changes in patients' cartilage thickness.

Ultrasound Measurement of Femoral Articular Cartilage Thickness Before and After Marathon Running.

The purpose of this study was to use ultrasonography to measure femoral articular cartilage thickness changes during marathon running, which could support MRI studies showing that deformation of knee cartilage during long-distance running is no greater than that for other weight-bearing activities. Participants included 38 marathon runners with no knee pain or history of knee injury, aged 18-39. Ultrasound images of the femoral articular cartilage were taken two hours before and immediately after the race. Femoral articular cartilage thickness was measured at both the medial and lateral femoral condyles. The maximum change in femoral articular cartilage thickness, measured at the left outer lateral femoral condyle, was 6.94% (P=.006). All other femoral articular cartilage thickness changes were not significant. A change in femoral articular cartilage thickness of 6.94% supports our hypothesis that long-distance running does not induce deformational changes greater than that of regular daily activities. This study using ultrasonography supports MRI evidence that knee cartilage tolerates marathon running well.

MRI T2 mapping and quantitative ultrasound shear wave elastography in cartilage integrity assessment for juvenile idiopathic arthritis patients

BackgroundJuvenile idiopathic arthritis (JIA) is the most common chronic rheumatic disease in childhood that can lead to irreversible cartilage damage, with associated disability and decreased life quality. Shear wave elastography and quantitative MRI mapping can be used to identify early cartilage affection. PurposeTo evaluate diagnostic utility of distal femoral cartilage shear wave elastography and MRI T2 mapping in patients with symptomatic knee and investigate their potential clinical significance.Material and methodsTwenty patients with knee affection (study group) and 20 volunteers with the same demographic characteristics but without symptomatic knee pain (control group) were included in the study. A total of 80 knee joints of 40 individuals were evaluated. At the medial, intercondylar, and lateral condylar levels, distal femoral cartilage thickness was measured by B-mode ultrasonography and MRI, stiffness was assessed by shear wave elastography, and T2 relaxation time was measured by MRI.ResultsThe medial, intercondylar, and lateral cartilage thickness measurements were similar between the two groups and no statistically significant difference was observed while measured by US (P value 0.653,0.702,0.607) and MRI (P value 0.414, 0.4187, 0.3903). The shear wave velocity values in the study group were significantly higher than in the control group (P value 0.0202). There was a statistically significant difference between the average T2 relaxation time values for the distal femoral cartilage in the study and the control groups (P value 0.0027). SWE results were statistically significant in moderate and high disease activity while T2* revealed statistically significant p values in low as well as moderate and high disease activity; we found the best cutoff values for detection of cases using shear wave elastography velocity ratio (m/sec) about 4.445 with significant p value = 0.02, sensitivity 59.3% and specificity = 70.45%.ConclusionShear wave elastography and MRI T2 mapping are reliable, non-invasive, and acceptable methods for the assessment of pathologic cartilage. Better diagnostic information of hyaline cartilage can be obtained by adding up an extra sequence called T2 mapping to the routine MRI protocol of knee.

Quantitative study of 3.0T MRI on the thickness of knee joint cartilage in healthy young people

To explore 3.0T MRI accurate measurement of knee cartilage thickness in healthy youth provides reliable anatomical parameters for quantitative diagnosis of osteoarthritis and accurate osteotomy of joint replacement. From January 2013 to December 2013, 30 healthy young volunteers including 14 males and 16 females with an average age of (25.8±2.4) years old ranging from 22 to 33 years were recruited in Changchun, Jilin Province, and a 3.0T MRI scan was performed on the bilateral knee joints of each volunteer. The cartilage thickness was measured on the lateral femoral condyle (LFC), medial femoral condyle (MFC), lateral tibial plateau (LTP) and medial tibial plateau (MTP). In four regions of the knee joint:LFC, MFC, LTP and MTP, whether young men or women, there was no significant difference in cartilage thickness between the left and right knee joints (P>0.05). There were significant differences in knee cartilage thickness between healthy young men and women (P<0.05). In the same sex group, LFC cartilage thickness was thinner in the middle, thicker in front and rear;MFC cartilage thickness was the thinnest in front and gradually thickening from the front to the rear; LTP cartilage thickness was thickest in the middle, second in the rear and thinnest in the front;MTP cartilage thickness was the thinnest in the front, was relatively uniform in the middle and rear and thicker than that in the front. In Northeast China, among healthy adults aged 22 to 33, gender difference may be an important factor in the difference of cartilage thickness in various regions of the knee joint. Regardless of whether male or female healthy young people, the cartilage thickness of the entire knee joint is unevenly distributed, but there is no significant difference in cartilage thickness in the same area between the left and right knee joints.

Ankylosing spondylitis impact on knee cartilage thickness: correlation with demographic data and clinical characteristics

BackgroundAnkylosing spondylitis (AS) is a progressive inflammatory disease involving cartilaginous structures in the spine and peripheral joints. However, the number of the studies assessing knee cartilage thickness in AS and its correlations with parameters of disease activity/severity is even less. We aimed to assess the impact of AS on knee cartilage thickness using musculoskeletal ultrasound (MSUS) and magnetic resonance imaging (MRI).MethodsTwenty-five AS patients and 25 healthy individuals (15 served for MSUS assessment, and 10 served for MRI assessment) were included. By employing MRI “using a 1.5-T machine” and MSUS “with a 10–18-MHz linear probe,” respectively, the thickness of the femorotibial cartilage and femoral cartilage was assessed.ResultsCompared to healthy controls, AS patients showed statistically significantly thinner cartilage thickness (P < 0.05) at all femorotibial cartilage subdivisions and the medial femoral condyle and intercondylar area on both sides. Femoral cartilage thickness measurements either assessed by MSUS or MRI were negatively correlated with age, measures of disease activity, and Bath Ankylosing Spondylitis Radiology Index for the spine (BASRI-s) (P < 0.05). However, MRI tibial cartilage thickness was negatively correlated with disease duration and measures of spinal mobility, functional limitation, and BASRI-s (P < 0.05). MRI total cartilage thickness measurements at the femoral condyle were negatively correlated with Bath Ankylosing Spondylitis Functional Index (BASFI) and Ankylosing Spondylitis Disease Activity Score-erythrocyte sedimentation rate (ASDAS ESR) (P = 0.04 and P = 0.03, respectively). A positive correlation was found between MSUS and MRI total femoral cartilage thickness (P = 0.02).ConclusionsThe knee cartilage thickness of AS patients was thinner than that of healthy controls. The correlations between cartilage thickness and patient variables demonstrate MSUS and MRI's utility in identifying knee cartilage loss areas in AS patients.

The Influence of Knee Position on Ultrasound Imaging of Femoral Cartilage in Individuals with Anterior Cruciate Ligament Reconstruction.

Articular cartilage is important for knee function and can be imaged using ultrasound. The purpose was to compare femoral cartilage thickness and echo intensity (EI) measured at 90° and 140° of knee flexion and between limbs in a cohort with unilateral anterior cruciate ligament reconstruction (ACLR). We also examined associations between gait biomechanics and cartilage outcomes. Twenty-seven individuals with primary unilateral ACLR participated (12 men, 15 women; age = 22.3 ± 3.8 years; time since ACLR = 71.2 ± 47.2 months). Ultrasound was used to obtain femoral cartilage measurements. Gait outcomes included peak KFA (knee flexion angle) and peak external knee flexion moment (KFM). Cartilage outcomes were compared using a 2 (position) × 2 (limb) repeated measures ANOVA (analysis of variance). Gait and cartilage associations were assessed using linear regression. There were no position × limb interactions for any cartilage outcome (all P > 0.05). Medial (P = 0.038) and central cartilage (P < 0.001) were thicker, whereas central (P = 0.029) and lateral cartilage EI (P = 0.003) were lower when measured at 90° than those at 140° of knee flexion. Medial cartilage was thicker in the ACLR than that in the contralateral limb (P = 0.016). A larger KFM was associated with thicker medial cartilage (ΔR2 = 0.146, P = 0.021) and central cartilage (ΔR2 = 0.159, P = 0.039) measured at 140° of knee flexion in the ACLR limb but not at 90°. Findings suggest that imaging position influences cartilage thickness and EI measurements in individuals with ACLR and should be considered in study designs and clinical evaluation. A greater KFM was associated with thicker cartilage within specific portions of the distal femur.

Usefulness of T2-Weighted Images with Deep-Learning-Based Reconstruction in Nasal Cartilage.

This study aims to evaluate the feasibility of visualizing nasal cartilage using deep-learning-based reconstruction (DLR) fast spin-echo (FSE) imaging in comparison to three-dimensional fast spoiled gradient-echo (3D FSPGR) images. This retrospective study included 190 set images of 38 participants, including axial T1- and T2-weighted FSE images using DLR (T1WIDL and T2WIDL, belong to FSEDL) and without using DLR (T1WIO and T2WIO, belong to FSEO) and 3D FSPGR images. Subjective evaluation (overall image quality, noise, contrast, artifacts, and identification of anatomical structures) was independently conducted by two radiologists. Objective evaluation including signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) was conducted using manual region-of-interest (ROI)-based analysis. Coefficient of variation (CV) and Bland-Altman plots were used to demonstrate the intra-rater repeatability of measurements for cartilage thickness on five different images. Both qualitative and quantitative results confirmed superior FSEDL to 3D FSPGR images (both p < 0.05), improving the diagnosis confidence of the observers. Lower lateral cartilage (LLC), upper lateral cartilage (ULC), and septal cartilage (SP) were relatively well delineated on the T2WIDL, while 3D FSPGR showed poorly on the septal cartilage. For the repeatability of cartilage thickness measurements, T2WIDL showed the highest intra-observer (%CV = 8.7% for SP, 9.5% for ULC, and 9.7% for LLC) agreements. In addition, the acquisition time for T1WIDL and T2WIDL was respectively reduced by 14.2% to 29% compared to 3D FSPGR (both p < 0.05). Two-dimensional equivalent-thin-slice T1- and T2-weighted images using DLR showed better image quality and shorter scan time than 3D FSPGR and conventional construction images in nasal cartilages. The anatomical details were preserved without losing clinical performance on diagnosis and prognosis, especially for pre-rhinoplasty planning.

Evaluation of the effect of high-intensity laser therapy (HILT) on function, muscle strength, range of motion, pain level, and femoral cartilage thickness in knee osteoarthritis: randomized controlled study.

This study was designed as a double-blind randomized placebo-controlled study. The aim of this study was to evaluate the effects of high-intensity laser therapy (HILT) on pain, range of motion, function, muscle strength, and femoral cartilage thickness in patients with knee osteoarthritis. Sixty patients who were admitted between November 2021 and April 2022 and diagnosed with knee osteoarthritis based on anamnesis, physical examination, and imaging methods were included in the study. The patients observed during the research were randomly divided into two groups with 30 patients in each group. Hotpack, transcutaneous electrical nerve stimulation (TENS), exercise (5days a week for a total of 15 sessions), and HILT (analgesic mode with a power of 10.0 w, energy density of 12 j/cm2, and 2min for every 25 cm2, biostimulant mode with a power of 5.0 W, energy density of 120 j/cm2, and 10min for each 25 cm2; total 9 sessions 3days a week) were applied for 3weeks for the first group, and hot pack, TENS, exercise (5days a week for a total of 15 sessions), and sham laser treatment (0 W total 9 sessions 3days a week) was applied for 3weeks for the second group. The patients were evaluated with the determined scales before the treatment, at the end of the treatment, and at the third month. A goniometer was used to measure joint range of motion measurement, a visual analog scale (VAS) for pain, WOMAC Osteoarthritis Index to assess pain and function, Biodex System 3 isokinetic device for knee flexion-extension muscle strength measurement, and ultrasonography to measure femoral cartilage thickness. There was no statistically significant difference in VAS, range of motion, WOMAC, muscle strength, and femoral cartilage thickness measurement between the groups, whether before treatment, after treatment or at the third-month follow-up (p > 0.05). There was a statistically significant decrease in pain intensity, an increase in flexion range of motion, WOMAC, and femoral cartilage thickness in both groups (p < 0.005). A statistically significant increase was found in the average peak torque flexion muscle strength measurements at isokinetic 60°/s angular velocities in the post-treatment and third-month checkup compared to the pre-treatment analysis in both groups (p < 0.05). In conclusion, there was no statistically significant difference between HILT + exercise and placebo laser + exercise observed. However, the exercise program performed under the supervision of a physiotherapist has been shown to be effective in improving all parameters.

Decreased Elastic Modulus of Knee Articular Cartilage Based on New Macroscopic Methods Accurately Represents Early Histological Findings of Degeneration.

Ex vivo nanoindentation measurement has reported that elastic modulus decreases as cartilage degenerates, but no method has been established to macroscopically evaluate mechanical properties in vivo. The objective of this study was to evaluate the elastic modulus of knee joint cartilage based on macroscopic methods and to compare it with gross and histological findings of degeneration. Osteochondral sections were taken from 50 knees with osteoarthritis (average age, 75 years) undergoing total knee arthroplasty. The elastic modulus of the cartilage was measured with a specialized elasticity tester. Gross findings were recorded as International Cartilage Repair Society (ICRS) grade. Histological findings were graded as Mankin score and microscopic cartilage thickness measurement. In ICRS grades 0 to 2 knees with normal to moderate cartilage abnormalities, the elastic modulus of cartilage decreased significantly as cartilage degeneration progressed. The elastic modulus of cartilage was 12.2 ± 3.8 N/mm for ICRS grade 0, 6.3 ± 2.6 N/mm for ICRS grade 1, and 3.8 ± 2.4 N/mm for ICRS grade 2. Similarly, elastic modulus was correlated with Mankin score (r = -0.51, P < 0.001). Multiple regression analyses showed that increased Mankin score is the most relevant factor associated with decreased elastic modulus of the cartilage (t-value, -4.53; P < 0.001), followed by increased histological thickness of the cartilage (t-value, -3.15; P = 0.002). Mechanical properties of damaged knee cartilage assessed with new macroscopic methods are strongly correlated with histological findings. The method has potential to become a nondestructive diagnostic modality for early cartilage damage in the clinical setting.

Investigation of the effect of plasma jet on regeneration of rabbit knee cartilage

Articular cartilage is a connective tissue biomechanically, so the absence of blood vessels, nerves, lymph flow and low metabolism causes its slow and delayed regeneration. Therefore, it is very important to use the correct treatment methods for cartilage healing. Рurpose of study: Investigating the effect of plasma jet on rabbit knee cartilage regeneration. The present research was conducted on 12 New Zealand white adult male rabbits weighing approximately 2.0-2.5 kg. In order to prepare the knee cartilage, its debridement was sanitized by chondrectomy with scraping method in all three treatment groups. After three weeks of treatment, the rabbits were euthanized and the amount of cartilage regeneration was recorded macroscopically and by recording images, and samples were fixed in 10% formalin for histopathology test. The commonly used in pathology laboratories staining method was chosen. Observation and measurement of articular cartilage thickness was done with eye graticule. And at the end, the obtained data were analyzed statistically. The results obtained in the present study indicated that the use of plasma jet method improves the cartilage tissue in such a way that by examining the histopathological sections, it was found that the articular cartilage in the plasma jet group caused the formation of fibrocartilage tissue in the place of injury. Plasma jet has a positive effect on rabbit cartilage regeneration.

Application of diffuse optical back reflection spectroscopy for determining articular cartilage thickness in a clinical setting.

Develop a spectroscopic method to assess cartilage thickness during the arthroscopic examination. Currently, arthroscopy assesses cartilage damage visually; outcomes are based on the surgeon's subjective experience. Light reflection spectroscopy is a promising method for measuring cartilage thickness based on the absorption of light by the subchondral bone. In the presented study, in vivo diffuse optical back reflection spectroscopic measurements were acquired by gently placing an optical fibre probe on different locations of the articular cartilage of 50 patients during complete knee replacement surgery. The optical fibre probe consists of two optical fibers with a diameter of 1mm to deliver the light and detect back-reflected light from the cartilage. Centre to centre distance between the source and the detectorfibers was 2.4mm. Actual thicknesses of the articular cartilage samples were measured under microscopy using histopathological staining. Using half of the samples in the patient data, a linear regression model was formed to estimate cartilage thicknesses from the spectroscopic measurements. The regression model was then used to predict the cartilage thickness in the second half of the data. The cartilage thickness was predicted with a mean error of 8.7% if the actual thickness was less than 2.5mm (R2 = 0.97). The outer diameter of the optical fibre probe was 3mm, which can fit into the arthroscopy channel and can be used to measure the cartilage thickness in real-time during the arthroscopic examination of the articular cartilage.

Imaging evaluation of physical activity effect on knee articular cartilage

IntroductionHyaline cartilage is a complex tissue with great load absorbing-function. Studies showed that moderate exercise can have a positive effect on chondral matrix composition but excessive can be harmful to cartilage. ObjectivesEvaluate knee cartilage thickness before and after physical activity (running) in healthy young individuals. MethodsTen healthy young adult male volunteers aged between 18 and 21 years old were selected to undergo magnetic resonance imaging examination of the right knee to measure the cartilage thickness of the anterior, medial, and lateral compartments before and after 1 hour of continuous running. Cartilage thickness measurements were performed by a radiologist who did not know the identity of the volunteers or the moment of the evaluation (before or after the exercise). ResultsThe subjects' mean age, height, and weight were 19.5 years, 1.80 m, and 75.2 kg, respectively, with a mean body mass index of 23.14. There was a decrease in chondral thickness after running on all surfaces evaluated. The changes that were relevant (P < .05) were all the medial femoral condyle, the anterior portion of the lateral femoral condyle, the anterior portion of the lateral plateau, the entire surface of the patella and trochlea. The greatest difference in thickness between before and after exercise was observed in the lateral facet of the patella (−0.224 mm) followed by the anterior surface of the medial femoral condyle (−0.186 mm). In proportional values, the highest decrease occurred in the anterior portion of the medial femoral condyle (−11.42%). ConclusionThere was a decrease in knee chondral thickness after 60 minutes of running, being statistically significant in the medial femoral condyle, anterior surface of the lateral femoral condyle, and lateral plateau and patellofemoral joint (patella and trochlea). Level of evidenceIV (Case Series).

Selection of Knees With Subsequent Cartilage Thickness Loss Based on Magnetic Resonance Imaging Semiquantitative Grading: Data From the Osteoarthritis Initiative Foundation for the National Institutes of Health Biomarker Cohort.

To investigate which magnetic resonance imaging (MRI)-based articular pathologies are predictive of subsequent medial femorotibial compartment quantitative cartilage thickness loss and therefore suitable for enrichment of clinical trials with participants showing a high likelihood for structural progression. Semiquantitative MRI Osteoarthritis Knee Score (MOAKS) assessments at baseline and quantitative cartilage thickness measurements at baseline and year-2 follow-up were performed in 599 participants (age 62 years; body mass index 31 kg/m2 ; 59% female) from the Osteoarthritis Initiative-based Foundation for the National Institutes of Health Osteoarthritis Biomarkers Consortium. Knees were classified as medial femorotibial compartment (MFTC) progressors or nonprogressors based on MFTC cartilage thickness change (smallest detectable change threshold -111 μm). Logistic regression was used to investigate the association between baseline presence and severity of MFTC MOAKS pathologies with subsequent MFTC progression. The standardized response mean (SRM) was computed to estimate the sensitivity to change that can be achieved when selecting knees based on MOAKS pathologies. Presence of MFTC MOAKS cartilage damage (odds ratio [OR] 2.77 [95% confidence interval (95% CI) 1.76, 4.36]), MFTC bone marrow lesions (OR 2.69 [95% CI 1.89, 3.83]), medial meniscus extrusion or damage (OR 2.21 [95% CI 1.37, 3.55]), as well as MOAKS severity subscales for cartilage and meniscus damage were associated with subsequent progression. The SRM was greater in knees with than in knees without the presence of these pathologies and was associated with the severity of those pathologies. MRI-based grading of articular pathologies makes it possible to specifically select progressor knees suitable for inclusion in clinical trials but also to identify knees in which treatment is not indicated (e.g., knees without cartilage damage despite presence of radiographic osteoarthritis).

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.

Worsening of Articular Tissue Damage as Defined by Semi-Quantitative MRI Is Associated With Concurrent Quantitative Cartilage Loss Over 24 Months.

To assess the association of worsening of magnetic resonance imaging (MRI) semi-quantitative (SQ) tissue features with concurrent change in quantitative (Q) cartilage thickness measurements over 24 months within the Foundation for the National Institutes of Health (FNIH) Biomarker Consortium study. In all, 599 participants were included. SQ assessment included cartilage damage, meniscal extrusion and damage, osteophytes, bone marrow lesions (BMLs), and effusion- and Hoffa-synovitis. Change in medial compartment Q cartilage thickness was stratified by concurrent ipsicompartmental SQ changes. Between-group comparisons were performed using analysis of covariance (ANCOVA) with adjustment for age, sex, and body mass index (BMI). Results were presented as adjusted mean difference. Knees with any increase in SQ cartilage scores in the medial compartment (n = 268) showed more Q cartilage loss compared to knees that remained stable (mean adjusted difference [MAD] = -0.16 mm, 95% confidence interval [CI]: [-0.19, -0.13] mm). Knees with any increase in meniscal extrusion in the medial compartment (n = 98) showed more Q cartilage loss than knees without (MAD = -0.18 mm, 95% CI: [-0.22, -0.14] mm. Comparable findings were seen for meniscal damage worsening. Regarding BMLs, an increase by one subregion resulted in a MAD of Q cartilage loss of -0.10 mm, 95% CI: [-0.14, -0.06] mm, while this effect almost tripled for change in two or more subregions. Increase in either effusion- and/or Hoffa-synovitis by one grade resulted in a MAD of -0.07 mm, 95% CI: [-0.10, -0.03] mm. Worsening of SQ cartilage damage, meniscal extrusion and damage, number of subregions affected by BML, maximum size of BMLs and worsening of effusion- and/or Hoffa synovitis is associated with increased Q cartilage loss.

IMAGING-BASED CHARACTERIZATION OF 3 DIFFERENT OA ENDOTYPES DERIVED FROM BIOCHEMICAL MARKERS - DATA FROM TWO OBSERVATIONAL COHORTS

A recent machine-learning study identified 3 different endotype clusters, based on serum and urine biomarker concentration patterns that were consistent between both the APPROACH and the OAI-based FNIH cohort. The clusters were characterized as systemic inflammation (SI), low tissue turnover (LTT), and structural damage of bone and articular cartilage (DAM, Fig. 1). To evaluate whether the prevalence of joint tissue pathologies (MRI Osteoarthritis Knee Scores (MOAKS)) and femorotibial joint (FTJ) cartilage thickness differ between these clusters, and whether 2-year changes in MOAKS scores and FTJ cartilage thickness differ between these 3 clusters. APPROACH enrolled 297 participants (age: 66.5±7.1y, BMI: 28.1±5.3 kg/m², 77.5% women, 55% KLG 2-4) and FNIH 600 OA patients (age: 61.5±8.8y, BMI: 30.7±4.8 kg/m², 58.8% women, 87.5% KLG 2-4). Of 295 APPROACH / 600 FNIH participants with biochemical marker levels available, 93/178 were assigned to the LTT cluster, 92/241 to the SI cluster, and 110/181 to the DAM cluster, respectively. Semi-quantitative MOAKS scores were assessed at months 0 and 24 by an experienced radiologist. FTJ cartilage thickness was measured at months 0 and 24 by manual, quality-controlled segmentations. Frequencies were compared using X² tests between the clusters, and cartilage thickness measures using t-tests. In APPROACH, baseline cartilage damage, osteophytes, effusion- and Hoffa-synovitis did not differ between the 3 clusters, while bone marrow lesions (BML) were more severe in the DAM cluster (Fig. 2). Medial meniscus damage was more severe in the LTT than the SI cluster (Fig. 2). In the FNIH cohort, baseline cartilage damage and BMLs were more severe in the DAM and SI clusters than in the LTT cluster (Fig. 2). Moreover, Hoffa-synovitis was more severe in the DAM than in the LTT cluster; no differences were observed for osteophytes or meniscus MOAKS scores (Fig. 2). In APPROACH, FTJ cartilage thickness was lower in the DAM than in the other clusters, while in FNIH, FTJ cartilage thickness was lower in both the DAM and SI than in the LTT cluster (data not shown). In APPROACH, the DAM cluster showed more 2-year worsening of full thickness cartilage damage, osteophytes, and medial meniscus extrusion than the LTT cluster and more worsening of osteophytes than the SI cluster (data not shown). In FNIH, the DAM cluster displayed more 2-year worsening of cartilage damage extent, lateral meniscus extrusion, and Hoffa-synovitis than the LTT cluster (data not shown). The LTT cluster showed more worsening in BMLs than the DAM cluster, and more worsening in osteophytes than the SI cluster. In both cohorts, change in FTJ cartilage thickness did not differ between clusters (data not shown). Differences in the severity of MR imaging features were more pronounced between clusters in the FNIH than in the APPROACH cohort, potentially because of the greater percentage of knees with radiographic knee OA (KLG2-4). Still, imaging features did not appear to be highly specific for the clusters derived from baseline biochemical markers, most likely because systemic biochemical markers are not only influenced by the selected target knee but also by other joints and tissue changes.

High spatial resolution analysis using automated indentation mapping differentiates biomechanical properties of normal vs. degenerated articular cartilage in mice.

Characterizing the biomechanical properties of articular cartilage is crucial to understanding processes of tissue homeostasis vs. degeneration. In mouse models, however, limitations are imposed by their small joint size and thin cartilage surfaces. Here we present a three-dimensional (3D) automated surface mapping system and methodology that allows for mechanical characterization of mouse cartilage with high spatial resolution. We performed repeated indentation mappings, followed by cartilage thickness measurement via needle probing, at 31 predefined positions distributed over the medial and lateral femoral condyles of healthy mice. High-resolution 3D x-ray microscopy (XRM) imaging was used to validate tissue thickness measurements. The automated indentation mapping was reproducible, and needle probing yielded cartilage thicknesses comparable to XRM imaging. When comparing healthy vs. degenerated cartilage, topographical variations in biomechanics were identified, with altered thickness and stiffness (instantaneous modulus) across condyles and within anteroposterior sub-regions. This quantitative technique comprehensively characterized cartilage function in mice femoral condyle cartilage. Hence, it has the potential to improve our understanding of tissue structure-function interplay in mouse models of repair and disease.

Preliminary outcomes of kinematically aligned robot-assisted total knee arthroplasty with patient-specific cartilage thickness measurement.

This study aimed to assess the preliminary outcomes of kinematically aligned robot-assisted total knee arthroplasty (TKA) with patient-specific cartilage thickness measurement. Patients who underwent kinematically aligned robot-assisted TKA were included in this study. Robot-assisted total knee arthroplasties were performed by NAVIO Surgical System (Smith & Nephew, Memphis, USA), an image-free handheld robotic system. The kinematic alignment technique was performed according to our intraoperative cartilage thickness measurement technique. Hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), joint-line orientation angle (JLOA), and joint-line convergence angle (JLCA) were measured through standing full-length anteroposterior radiographs. Knee Injury and Osteoarthritis Outcome Score, Oxford score, VAS pain and satisfaction score, and Forgotten Joint Score were used to assess clinical outcomes. A total of 142 knees of 109 patients (92 females and 17 males) were evaluated in this study. There was a significant correction in HKA, JLCA, and mMPTA postoperatively (p ≤0.001, < 0.001, and 0.029, respectively). We observed no significant change in mLDFA and JLOA measurements. All clinical scores significantly increased at the latest follow-up. Our results demonstrated that kinematically aligned robot-assisted TKA with patient-specific cartilage thickness measurement demonstrated no significant change in mLDFA and JLOA, as expected; however, significantly corrected the deformity in HKA, mMPTA, and JLCA measurements.