Cartilage Volume Measurements Research Articles

CNN‐based fully automatic wrist cartilage volume quantification in MR images: A comparative analysis between different CNN architectures

Automatic measurement of wrist cartilage volume in MR images. We assessed the performance of four manually optimized variants of the U-Net architecture, nnU-Net and Mask R-CNN frameworks for the segmentation of wrist cartilage. The results were compared to those from a patch-based convolutional neural network (CNN) we previously designed. The segmentation quality was assessed on the basis of a comparative analysis with manual segmentation. The best networks were compared using a cross-validation approach on a dataset of 33 3D VIBE images of mostly healthy volunteers. Influence of some image parameters on the segmentation reproducibility was assessed. The U-Net-based networks outperformed the patch-based CNN in terms of segmentation homogeneity and quality, while Mask R-CNN did not show an acceptable performance. The median 3D DSC value computed with the U-Net_AL (0.817) was significantly larger than DSC values computed with the other networks. In addition, the U-Net_AL provided the lowest mean volume error (17%) and the highest Pearson correlation coefficient (0.765) with respect to the ground truth values. Of interest, the reproducibility computed using U-Net_AL was larger than the reproducibility of the manual segmentation. Moreover, the results indicate that the MRI-based wrist cartilage volume is strongly affected by the image resolution. U-Net CNN with attention layers provided the best wrist cartilage segmentation performance. In order to be used in clinical conditions, the trained network can be fine-tuned on a dataset representing a group of specific patients. The error of cartilage volume measurement should be assessed independently using a non-MRI method.

POS0277 ANABOLIC EFFECT OF LNA043, A NOVEL DISEASE-MODIFYING OSTEOARTHRITIS DRUG CANDIDATE: RESULTS FROM AN IMAGING-BASED PROOF-OF-CONCEPT TRIAL IN PATIENTS WITH FOCAL ARTICULAR CARTILAGE LESIONS

Background:LNA043 is a modified, recombinant version of the human angiopoietin-like 3 (ANGPTL3) protein acting directly on cartilage-resident cells to transmit its cartilage anabolic effect. A first-in-human study previously demonstrated the favourable safety profile and the modulation of several pathways involved in cartilage homeostasis and osteoarthritis (OA)1. A previous proof-of-mechanism imaging study used high field (7 Tesla) magnetic resonance imaging (MRI) to show formation of hyaline-like tissue after a single injection of 20 mg LNA043 (unpublished data).Objectives:To evaluate non-invasively the chondro-regenerative capacity of multiple intra-articular (i.a.) injections of LNA043 in patients with articular cartilage lesions in the knee (NCT03275064).Methods:This was a randomised, double-blind, placebo (PBO)-controlled, proof-of-concept study in patients with a partial thickness cartilage lesion. In total, 58 patients (43 [20 mg LNA043]; 15 [PBO]), stratified by lesion type (condylar or patellar) were treated with 4 weekly i.a. injections. The primary endpoint was T2 relaxation time measurement as a marker of collagen fiber network, and cartilage lesion-volume was a secondary endpoint, both using 3-Tesla MRI. Assessments were performed at baseline, weeks (wks) 8, 16, 28 and 52 (the latter in 23/58 patients). While lesion-volume for the secondary endpoint was determined from manually segmented images, the cartilage volume of 21 sub-regions spanning the entire knee was also measured from 3D isotropic MR images employing an automated segmentation prototype software (MR Chondral Health 2.1 [MRCH], Siemens Healthcare)2. An exploratory analysis evaluated the treatment effect for the additive volume of the 3 subregions in the weight-bearing area of the medial femur.Results:No change in T2 relaxation time was detected between treatment and PBO groups. Manual segmentation showed continuous filling of the cartilage lesions up to wk 28 in LNA043-treated patients with femoral lesions (p=0.08, vs PBO) while no effect was detected for patients with patellar lesions. Given the limitations of measuring small, irregularly shaped lesions with manual image-analysis, the MRCH approach was used (Figure 1). In the medial femoral weight-bearing region, refilling was detected over time (Δ=123 mm3 at wk 28, N= 37, p= 0.05). No overgrowth was detected in the lateral femoral condyles without cartilage damage. The overall safety profile was favourable; only mild/moderate local reactions were reported, including a higher incidence of joint swelling (9.3% vs 0%) and arthralgia (11.6% vs 6.7%) for LNA043 vs PBO resolving spontaneously or with paracetamol/NSAIDs. No anti-drug antibodies were detected.Conclusion:Treatment with 4 weekly i.a. injections of 20 mg LNA043 resulted in regeneration of damaged cartilage in patients with femoral articular cartilage lesions. Automated measurement of cartilage volume in the femoral index region was able to detect a relevant treatment effect and was found to be more sensitive than the manual segmentation method. No sign of cartilage overgrowth was observed in healthy femoral regions. A Phase 2b study in patients with mild to moderate knee OA is in preparation.

Serum vitamin D and knee osteoarthritis: is its role over-emphasized?

Purpose: Vitamin D deficiency (VDD) is a global health problem that impacts the musculoskeletal health. Approximately 70-90% of apparently healthy population is vitamin D deficient in India. Similarly, VDD has been reported to be prevalent globally. It is widespread irrespective of age, sex, profession, rural/urban settings or regional distribution. Low levels of serum 25(OH)D has been reported to be associated with many diseases including knee Osteoarthritis (KOA). Recently we have reported that vitamin D supplementation in KOA with hypovitaminosis D improves clinico-radiological severity; however we did not study the comparison of clinico- radiological severity in KOA cases of vitamin D sufficient (VDS) levels and vitamin D deficient (VDD) levels. This cross-sectional case control study was conducted to correlate the serum vitamin D levels with clinical scores (VAS and WOMAC) and radiological severity (KL grade and articular cartilage volume) in KOA subjects with VDD (<30 ng/ml) as cases and with VDS levels as controls. Methods: The present study was conducted in the Dept of Orthopaedic Surgery, King George’s Medical University, Lucknow. 180 subjects of either gender with primary KOA were recruited using American College of Rheumatology criteria for diagnosis. Biochemical assessment of subjects was done for serum 25(OH) D. Subjects were divided into two groups: Group 1 with sufficient serum vitamin D level (VDS) and Group 2 with hypovitaminosis D or VDD. Clinical severity was assessed by self- reported Western Ontario Mac Master University Index Scores for knee pain, stiffness, physical function and total scores of the subjects. Visual Analogue Scale Score was also used for knee pain on 0-10 point scale. Serum 25(OH) D level was correlated with all the clinical parameters. Radiological severity on X-ray was assessed by using Kellgren and Lawrence (KL) grading system in all the subjects. Articular cartilage volume (ACV) measurement was done using MRI in 100 subjects (50 in each group). The study was approved by Institutional Ethics Committee, KGMU. Informed consent was obtained from all the participants. Data was analyzed using statistical software SPSS 16.0. Student t test was used to analyze continuous data. Pearson Correlation Coefficient and one way ANOVA were used to correlate continuous and categorical variables respectively. Results: Mean serum vitamin D levels in Group 1 and Group 2 were 34.96±4.2 and 16.03±7.01 ng/ml respectively and the difference was significant (p<0.0001). Continuous variables viz; clinical parameters and ACV were compared between both the groups and a statistically significant difference was observed (WOAMC pain: p=0.012, stiffness: p=0.022, physical function: p=0.043, total WOMAC: p=0.016, VAS: p= 0.034 and ACV: p=0.037). Group 1: Mean scores for WOMAC pain, stiffness, physical function, total WOMAC and VAS in Group 1 were 9.83±2.16, 2.18±0.24, 21.47±6.26, 33.85±8.71 and 5.98±1.01 respectively. An insignificant negative correlation of serum 25(OH) D was observed with all the clinical variables (WOAMC pain: p=0.218, stiffness: p=0.094, physical function: p=0.139, total WOMAC: p=0.073 and VAS: p=0.104). Mean serum vitamin D levels in KL grades 2, 3 and 4 were 36.14±5.26, 34.19±4.69 and 33.28±4.02 ng/ml respectively. An insignificant association was observed between serum vitamin D and KL grade (p=0.381). Mean ACV in KOA subjects was 4.927±0.86cm3. An insignificant association was observed between serum 25(OH) D and ACV (p=0.422). Group 2: Mean scores for WOMAC pain, stiffness, physical function, total WOMAC and VAS in Group 2 were 10.94±3.63, 2.52±1.38, 23.41±6.51, 37.06±9.06 and 6.27±0.8 respectively. A significant negative correlation of serum 25(OH)D was observed with all the clinical variables (WOAMC pain: p<0.001, stiffness: p=0.047, physical function: p<0.001, total WOMAC: p<0.001 and VAS: p= 0.041). Mean serum vitamin D levels in KL grades 2, 3 and 4 were 18.07±7.95, 16.95±7.56 and 15.03±8.35 ng/ml respectively. A statistically insignificant association was observed between serum vitamin D and KL grade (p=0.478). Mean ACV in KOA subjects was 4.415±1.49cm3. An insignificant association was observed between serum 25(OH) D and ACV (p=0.759). Conclusions: This study found that in KOA subjects having VDD levels, significant association existed with all the clinical features studied and insignificant association with those having VDS levels. This validates the contention that VDD plays a significant role in pain and other symptoms experienced by KOA subjects. Contrary to this were our findings with radiology. In both the groups of KOA with VDD and VDS levels, insignificant association/ correlation was found with the radiological features studied viz. KL grades and ACV. Whereas the clinical features are more subjective, radiological features are not only objective, they also closely reflect the morphological changes undergone in any given disease. The lack of association between the levels of vitamin D and the radiological features in KOA subjects needs to be examined before the hype of vitamin D in controlling KOA, as they are truer representation of the disease process and the severity.

Quantitative measurement of cartilage volume is possible using two-dimensional magnetic resonance imaging data sets

3D Magnetic resonance imaging (MRI) scans are generally used for quantitative cartilage measurements in knee osteoarthritis. However, a great deal of MRI data is from 2D scans, often thought to be unsuitable for quantitative cartilage assessment. The goal of our study was to demonstrate that mLACS, a modified version of the Local Area Cartilage Segmentation (LACS) method, could be used to measure cartilage volume on 2D MRI images. We studied 301 randomly selected subjects from the OA Biomarkers Consortium FNIH Study, a nested case-control study within the Osteoarthritis Initiative (OAI). The study comprised four subgroups based on radiographic and pain progression. We compared mLACS applied to 2D TSE scans to LACS on 3D DESS data. The Pearson's correlation coefficient was used to establish agreement between LACS and mLACS, standardized response means (SRMs) for responsiveness, and intra-class correlation coefficients (ICCs) to measure reader precision. Logistic regression in a case/control analysis was used to compare the clinical validity between the two methods. We found R2=0.76 for the correlation between LACS and mLACs. For LACS, the responsiveness was SRM=0.49 compared to 0.39 for mLACS. The odds ratios (OR) for the primary case/control analyses were 1.62 for LACS and 1.78 for mLACS. The intra and inter reader reproducibility values for mLACS were ICC=0.90 and 0.86, respectively. This study has demonstrated that a reproducible, responsive, and clinically valid quantitative measurement of cartilage volume can be made using 2D TSE scans with a modest loss of responsiveness compared to 3D scans.

Murine articular cartilage morphology and compositional quantification with high resolution cationic contrast-enhanced μCT.

Articular cartilage lines the load-bearing surfaces of long bones and undergoes compositional and structural degeneration during osteoarthritis progression. Contrast enhanced microcomputed tomography (μCT) is being applied to a variety of preclinical models, including the mouse, to map structural and compositional properties in 3-D. The thinness (∼30-50 μm) and high cellularity of mouse articular cartilage presents a significant imaging challenge. Our group previously showed that mouse articular cartilage and proteoglycan (PG) content can be assessed by μCT with the ioxagalate-based contrast agent Hexabrix, but the voxel size used (6 μm) was deemed to be barely adequate. The objective of the present study is to assess the utility of a novel contrast agent, CA4+, to quantify mouse articular cartilage morphology and composition with high resolution μCT imaging (3 μm voxels) and to compare the sensitivity of CA4+ and Hexabrix to detect between-group differences. While both contrast agents are iodine-based, Hexabrix is anionic and CA4+ is cationic so they interact differently with negatively charged PGs. With CA4+, a strong correlation was found between non-calcified articular cartilage thickness measurements made with histology and μCT (R2 = 0.72, p < 0.001). Cartilage degeneration-as assessed by loss in volume, thickness, and PG content-was observed in 34-week-old mice when compared to both 7- and 12-week-old mice. High measurement precision was observed with CA4+, with the coefficient of variation after repositioning and re-imaging samples equaling 2.8%, 4.5%, 7.4% and 5.9% for attenuation, thickness, volume, and PG content, respectively. Use of CA4+ allowed increased sensitivity for assessing PG content compared to Hexabrix, but had no advantage for measurement of cartilage thickness or volume. This improvement in imaging should prove useful in preclinical studies of cartilage degeneration and regeneration. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:2740-2748, 2017.

Quantitative Measurement of Cartilage Volume is Possible Using Two-Dimensional Magnetic Resonance Imaging Data Sets

Quantitative Measurement of Cartilage Volume is Possible Using Two-Dimensional Magnetic Resonance Imaging Data Sets

Associations between endogenous sex hormones and MRI structural changes in patients with symptomatic knee osteoarthritis.

To investigate the longitudinal association between endogenous sex hormones and knee osteoarthritis (OA) structures and pain. We examined 200 participants (mean age 63.0±7.3 years) from a clinical trial of vitamin D supplement for symptomatic knee OA. Serum levels of estradiol, progesterone, testosterone and sex hormone binding globulin (SHBG) were analyzed at baseline and 24 months later. Magnetic resonance imaging (MRI) scans of selected knee were obtained at both baseline and follow-up for the measurement of cartilage volume, cartilage defects, bone marrow lesions (BMLs) and effusion-synovitis volume. Knee pain was assessed using a 100mm visual analogue scale (VAS). Longitudinal data were analyzed using linear mixed-effects model. One hundred and seven males and 93 females were included in this study. For females, after adjustment for age, body mass index (BMI), and vitamin D level, progesterone was positively associated with cartilage volume (β=0.12mm3 per quartile, P<0.01). Estradiol levels were associated with lower grades of BMLs (β=-0.46 per quartile, P=0.03), while estradiol (β=-1.28 per quartile, P=0.04), progesterone (β=-1.56 per quartile, P<0.01) and testosterone (β=-1.51 per quartile, P=0.01) were inversely associated with effusion-synovitis volume. Testosterone was inversely associated with knee pain. No consistent associations were observed for males. In women but not men, low serum levels of endogenous estradiol, progesterone and testosterone are associated with increased knee effusion-synovitis and possibly other OA-related structural changes. This may contribute to observed sex differences in knee OA.

Tibial cartilage volume measurement in knee osteoarthritis using magnetic resonance imaging

Abstract Background Cartilage degeneration is considered as the initial defect in osteoarthritis. Measurement of cartilage volume is important to monitor disease progression and therapeutic response. Objectives To measure tibial cartilage volume using magnetic resonance imaging (MRI), and to evaluate the accuracy and interobserver reliability of tibial cartilage volume measurement using MRI. Methods The outline boundaries of the medial and lateral tibial cartilage were drawn manually on 1 mm slices using a track-ball to calculate the volume of each slice. Total calculated MRI-derived tibial cartilage volume was determined by summation of the slice volumes. The calculated tibial cartilage volume was compared to the actual tibial cartilage volume. Results There was a strong correlation between the calculated and actual tibial cartilage volumes determined by a radiologist and a researcher (98% and 89% agreement in medial tibial cartilage, 99% and 97% agreement in lateral tibial cartilage, respectively). High observer reliability was identified (92% agreement in medial tibial cartilage and 97% agreement in lateral tibial cartilage). Conclusion Tibial cartilage volume measurement using MRI can be easily performed by well-trained personnel such as radiologists or residents, and can be used to estimate tibial cartilage volume preoperatively in total knee arthroplasty, and to monitor disease progression and response to therapy.

Prediction of medial tibiofemoral compartment joint space loss progression using volumetric cartilage measurements: Data from the FNIH OA biomarkers consortium.

Investigating the association between baseline cartilage volume measurements (and initial 24th month volume loss) with medial compartment Joint-Space-Loss (JSL) progression (>0.7mm) during 24-48th months of study. Case and control cohorts (Biomarkers Consortium subset from the Osteoarthritis Initiative (OAI)) were defined as participants with (n=297) and without (n=303) medial JSL progression (during 24-48th months). Cartilage volume measurements (baseline and 24th month loss) were obtained at five knee plates (medial-tibial, lateral-tibial, medial-femoral, lateral-femoral and patellar), and standardized values were analysed. Multivariate logistic regression was used with adjustment for known confounders. Artificial-Neural-Network analysis was conducted by Multi-Layer-Perceptrons (MLPs) including baseline determinants, and baseline (1) and interval changes (2) in cartilage volumes. Larger baseline lateral-femoral cartilage volume was predictive of medial JSL (OR: 1.29 (1.01-1.64)). Greater initial 24th month lateral-femoral cartilage volume-loss (OR: 0.48 (0.27-0.84)) had protective effect on medial JSL during 24-48th months of study. Baseline and interval changes in lateral-femoral cartilage volume, were the most important estimators for medial JSL progression (importance values: 0.191(0.177-0.204), 0.218(0.207-0.228)) in the ANN analyses. Cartilage volumes (both at baseline and their change during the initial 24months) in the lateral femoral plate were predictive of medial JSL progression. • Baseline lateral femoral cartilage volume is directly associated with medial JSL progression. • 24-month lateral femoral cartilage loss is inversely associated with medial JSL progression. • Lateral femoral cartilage volume is most important in association with medial JSL progression.

Using quantitative measurement of knee cartilage volume by 3.0T magnetic resonance imaging in diagnosing osteoarthritis

Using quantitative measurement of knee cartilage volume by 3.0T magnetic resonance imaging in diagnosing osteoarthritis

Automated cartilage visualization and volume measurement using 3D U-shape and gaussian filter

Automated cartilage visualization and volume measurement using 3D U-shape and gaussian filter

Bone marrow lesions detected by specific combination of MRI sequences are associated with severity of osteochondral degeneration.

BackgroundBone marrow lesions (BMLs) are useful diagnostic and prognostic markers in knee osteoarthritis (OA), but what they represent at the tissue level remains unclear. The aim of this study was to provide comprehensive tissue characterization of BMLs detected using two specific MRI sequences.MethodsTibial plateaus were obtained from 60 patients (29 females, 31 males), undergoing knee arthroplasty for OA. To identify BMLs, MRI was performed ex vivo using T1 and PDFS-weighted sequences. Multi-modal tissue level analyses of the osteochondral unit (OCU) were performed, including cartilage volume measurement, OARSI grading, micro-CT analysis of bone microstructure, routine histopathological assessment and quantitation of bone turnover indices.ResultsBMLs were detected in 74 % of tibial plateaus, the remainder comprising a No BML group. Of all BMLs, 59 % were designated BML 1 (detected only by PDFS) and 41 % were designated BML 2 (detected by both PDFS + T1). The presence of a BML was related to degeneration of the OCU, particularly within BML 2. When compared to No BML, BML 2 showed reduced cartilage volume (p = 0.008), higher OARSI scores (p = 0.004), thicker subchondral plate (p = 0.002), increased trabecular bone volume and plate-like structure (p = 0.0004), increased osteoid volume (p = 0.002) and thickness (p = 0.003), more bone marrow oedema (p = 0.03), fibrosis (p = 0.002), necrosis (p = 0.01) and fibrovascular cysts (p = 0.04). For most measures, BML 1 was intermediate between No BML and BML 2.ConclusionsBMLs detected by specific MRI sequences identify different degrees of degeneration in the OCU. This suggests that MRI characteristics of BMLs may enable identification of different BML phenotypes and help target novel approaches to treatment and prevention of OA.

Does cartilage volume measurement or radiographic osteoarthritis at baseline independently predict ten-year cartilage volume loss?

BackgroundThe aim of this study was to examine whether cartilage volume as measured by MRI and radiographic osteoarthritis (OA) at baseline predict cartilage volume loss over ten years independent of each other and other structural co-pathologies.Methods219 participants [mean-age 45(26–61); 57 % female] were studied at baseline and ten years. Approximately half were the adult offspring of subjects who underwent knee replacement for OA and the remainder were randomly selected controls. Joint space narrowing (JSN) and osteophytes were assessed on radiographs and cartilage volume (tibiofemoral), cartilage defects, bone marrow lesions and meniscal tears/extrusion were assessed on MRI.ResultsMean absolute and percentage per annum cartilage volume loss was 1284 mm3 and 1.91 % respectively in the medial compartment and 1007 mm3 and 1.38 % respectively in the lateral compartment. Higher baseline tibiofemoral cartilage volume was independently associated with greater absolute cartilage volume loss in both medial (β(95 % CI) = −300 (−399,−200)) and lateral (β = −338 (−443,−233)) compartments and percentage per annum loss in the lateral compartment(β = −0.15 (−0.29, −0.01)). Baseline JSN and osteophytes were associated with cartilage volume loss in the univariable analysis, however these associations did not persist after adjustment for other structural co-pathologies.ConclusionCross-sectional cartilage volume measurement independently predicts cartilage volume loss over 10 years and can be used to identify fast progressors in clinical trials. Radiographic JSN and osteophytes on the other hand are a reflection of other co-pathologies assessed on MRI and do not independently predict cartilage volume loss over 10 years.

Accurate and precise cartilage volume and thickness measurements assessed by high resolution micro-computed tomography in non OA knees

Accurate and precise cartilage volume and thickness measurements assessed by high resolution micro-computed tomography in non OA knees

Reproducibility analysis of knee circumference in individuals with osteoarthritis

Knee osteoarthritis presents pain, loss of function, and joint swelling as its main symptoms. The joint swelling is defined as an accumulation of fluid in the joint due to the inflammatory process that contributes to progressive joint damage; it causes limitation in the range of knee motion, decreases proprioception, and affects the functional capacity and the quality of life of the individual. The measurement of articular cartilage volume is essential in clinical practice. The measurement of knee circumference using a measuring tape is a widely used, inexpensive, and accessible technique. However, as it is considered subjective, there is no evidence to support its use. Objective: To examine the reproducibility of this technique in patients with knee osteoarthritis. Method: Participants underwent two evaluations performed by two independent raters, at different times. The measurement of knee circumference was performed using a measuring tape 150 cm in length, taking as reference the superior pole of the patella. Results: The knee circumferences of 114 individuals were measured. According to the intraclass correlation coefficient (ICC), we observed a strong correlation (ICC = 0.98) between raters. Conclusion: The use of a measuring tape as a resource to measure knee circumference in individuals with osteoarthritis is a reliable and reproducible method.

Cartilage damage, bone marrow lesions and meniscal lesions predict quantitatively measured loss of cartilage over 30-months: the most study

Cartilage damage, bone marrow lesions and meniscal lesions predict quantitatively measured loss of cartilage over 30-months: the most study

Changes in articular cartilage and posterior meniscus geometries after anterior cruciate ligament injury

Changes in articular cartilage and posterior meniscus geometries after anterior cruciate ligament injury

Reproducibility analysis of knee circumference in individuals with osteoarthritis

Knee osteoarthritis presents pain, loss of function, and joint swelling as its main symptoms. The joint swelling is defined as an accumulation of fluid in the joint due to the inflammatory process that contributes to progressive joint damage; it causes limitation in the range of knee motion, decreases proprioception, and affects the functional capacity and the quality of life of the individual. The measurement of articular cartilage volume is essential in clinical practice. The measurement of knee circumference using a measuring tape is a widely used, inexpensive, and accessible technique. However, as it is considered subjective, there is no evidence to support its use. Objective: To examine the reproducibility of this technique in patients with knee osteoarthritis. Method: Participants underwent two evaluations performed by two independent raters, at different times. The measurement of knee circumference was performed using a measuring tape 150 cm in length, taking as reference the superior pole of the patella. Results: The knee circumferences of 114 individuals were measured. According to the intraclass correlation coefficient (ICC), we observed a strong correlation (ICC = 0.98) between raters. Conclusion: The use of a measuring tape as a resource to measure knee circumference in individuals with osteoarthritis is a reliable and reproducible method.

Towards the identification of early stage osteoarthritis

A variety of genetic and environmental factors contribute to the progressive develop of OA. It is necessary to identify people who are developing initial changes in cartilage and/or subchondral bone before onset of classical radiological features in order to detect early phase of OA. Recent quantitative MRI techniques can evaluate the structural, mechanical and biochemical characteristics of cartilage. T2 mapping is able to assess cartilage volume and defects measurement, delayed gadolinium enhanced MRI (dGEMRIC) and Contrast Enhanced Computed Tomography (CECT) can reveal Cartilage GAG content. Accurate and reliable serum, urine and synovial fluid biomarkers are also requested. Several biomarkers have been studied and proposed, but there are many critical issues to consider for inferring useful data from studies on biomarkers in early OA such as phase of disease, specific joint sites, systemic concentrations, circadian rhythm, their clearance from the joint, etc. Recently proteomics has produced great expectations to improve the early diagnosis of OA. These discoveries may open opportunities for the identification of early stage of OA leading to manage the symptoms and ultimately slow the progression of OA.

Association between hip and knee cartilage measured using radiographs and magnetic resonance imaging: the Tasmanian Older Adult Cohort Study

Cartilage loss is a key pathological feature of OA and can be assessed indirectly using radiography or directly through MRI. A number of cross-sectional studies have suggested that primary generalized osteoarthritis (PGOA) may be a distinct disease, but despite the high frequency of involvement of the hip and the knee joints in OA, very few studies have looked at the radiographic association between these two joints, and none has done so using MRI. The aim of this study was to examine the association of hip and knee cartilage measured by both radiography and MRI. We studied 151 participants from the Tasmanian Older Adult Cohort (TASOAC) study, who were selected randomly from the southern Tasmanian electoral rolls. MRI was used to assess hip and knee cartilage volume and radiography was used to assess joint space narrowing (JSN). Correlation analyses were used to compare cartilage volume measurements and JSN. In adjusted analysis, there was a consistent, positive association between knee and hip cartilage volume that was best for total knee cartilage volume (r = 0.16-0.40, all P < 0.05). In contrast, there was at best a weak correlation, depending on the site, between hip and knee JSN (r = -0.01 to 0.21). Hip and knee cartilage volume are more strongly associated than hip and knee JSN, suggesting a commonality of cartilage volume at different anatomic sites. The weaker radiographic association may reflect less measurement error with MRI or the contribution of multiple structures to joint space in the knee.