Long term evaluation of disease progression through the quantitative magnetic resonance imaging of symptomatic knee osteoarthritis patients: correlation with clinical symptoms and radiographic changes

Obesity increases the prevalence and severity of focal knee abnormalities diagnosed using 3T MRI in middle-aged subjects--data from the Osteoarthritis Initiative

OBJECTIVE

To study the effect of BMI on the prevalence, severity, and 36-month progression of early degenerative changes in the knee by using 3T MRI in middle-aged subjects without radiographic osteoarthritis (OA).

MATERIALS AND METHODS

We examined baseline and 36-month follow-up MR studies from 137 middle-aged individuals (45-55 years old) with risk factors for knee OA but no radiographic OA from the Osteoarthritis Initiative. Subjects were grouped into three categories: normal BMI (BMI < 25 kg/m(2), n = 38), overweight (BMI 25-29.9 kg/m(2), n = 37), and obese (BMI ≥ 30 kg/m(2), n = 62). Using 3T MRI, cartilage, meniscus, and bone marrow abnormalities were graded using the OA Whole-organ MR Imaging Score (WORMS). The statistical analysis was corrected as necessary for differences in age, sex, and OA risk factors other than BMI.

RESULTS

The overall prevalence of lesions was 64% for meniscus and 79% for cartilage (including low grade lesions). At baseline, the prevalence and severity of knee lesions was positively associated with BMI, with a nearly fourfold increase in meniscal tears and more than twofold increase in high-grade cartilage defects in obese individuals relative to normal-weight subjects. Over the 36-month follow-up period, the number of new or worsening cartilage lesions of any grade was significantly higher in obese subjects (p = 0.039), while there was no significant difference in meniscal lesion progression.

CONCLUSION

Obesity was associated with both higher prevalence and severity of early degenerative changes in the knee in middle-aged individuals without radiographic OA and with significantly increased cartilage lesion progression (of any grade) over 36 months.

Use magnetic resonance imaging to assess articular cartilage

Magnetic resonance imaging (MRI) enables a noninvasive, three-dimensional assessment of the entire joint, simultaneously allowing the direct visualization of articular cartilage. Thus, MRI has become the imaging modality of choice in both clinical and research settings of musculoskeletal diseases, particular for osteoarthritis (OA). Although radiography, the current gold standard for the assessment of OA, has had recent significant technical advances, radiographic methods have significant limitations when used to measure disease progression. MRI allows accurate and reliable assessment of articular cartilage which is sensitive to change, providing the opportunity to better examine and understand preclinical and very subtle early abnormalities in articular cartilage, prior to the onset of radiographic disease. MRI enables quantitative (cartilage volume and thickness) and semiquantitative assessment of articular cartilage morphology, and quantitative assessment of cartilage matrix composition. Cartilage volume and defects have demonstrated adequate validity, accuracy, reliability and sensitivity to change. They are correlated to radiographic changes and clinical outcomes such as pain and joint replacement. Measures of cartilage matrix composition show promise as they seem to relate to cartilage morphology and symptoms. MRI-derived cartilage measurements provide a useful tool for exploring the effect of modifiable factors on articular cartilage prior to clinical disease and identifying the potential preventive strategies. MRI represents a useful approach to monitoring the natural history of OA and evaluating the effect of therapeutic agents. MRI assessment of articular cartilage has tremendous potential for large-scale epidemiological studies of OA progression, and for clinical trials of treatment response to disease-modifying OA drugs.

Comparison between different implementations of the 3D FLASH sequence for knee cartilage quantification

OBJECTIVE

To compare several sequence implementations of the 3D FLASH sequence in the context of quantitative cartilage imaging.

MATERIALS AND METHODS

Test-retest coronal fast low angle shot (FLASH) sequences with water excitation were acquired in knees of 12 healthy participants, using two 1.5 T scanners from the same manufacturer. On one of the scanners, the FLASH was additionally compared with a FLASH VIBE, 75% with 100% slice resolution, a non-selective with a conventional spatial pulse, and "asymmetric echo allowed" with "not allowed".

RESULTS

Implementations of the FLASH showed systematic differences of up to 3.3%, but these were not statistically significant. Precision errors were similar between protocols, but tended to be smallest for the FLASH VIBE with 100% slice resolution (0.6-6.7%). In the medial tibia cartilage volume and thickness differed significantly (P < 0.01; 6.2 and 5.9%) between the two scanners.

CONCLUSION

Using a validated FLASH sequence, one can reduce slice resolution to 75% and allow asymmetric echo without sacrificing precision, in order to reduce the total acquisition time. However, in longitudinal studies, the scanner and the specific sequence implementation should be kept constant between baseline and follow-up, in order to avoid systematic off-sets in the measurements.

The associations between parity, other reproductive factors and cartilage in women aged 50-80 years

OBJECTIVE

Sex hormones and reproductive factors may be important for osteoarthritis (OA). The aim of this study was to describe the associations of parity, use of hormone replacement therapy (HRT) and oral contraceptives (OCs) with cartilage volume, cartilage defects and radiographic OA in a population-based sample of older women.

DESIGN

Cross-sectional study of 489 women aged 50-80 years. Parity, use of HRT and OC was assessed by questionnaire; knee cartilage volume and defects by magnetic resonance imaging and knee joint space narrowing (JSN) and osteophytes by X-ray.

RESULTS

Parity was associated with a deficit in total knee cartilage volume [adjusted β=-0.69 ml, 95% confidence interval (CI) -1.34, -0.04]. Increasing parity was associated with decreasing cartilage volume in both the tibial compartment and total knee (both P trend <0.05). Parity was also associated with greater cartilage defects in the patella compartment [adjusted odds ratio (OR)=2.87, 95% CI=1.39, 5.93] but not other sites. There was a consistent but non-significant increase in knee JSN (OR=2.78, 95% CI=0.75, 10.31) and osteophytes (OR=1.69, 95% CI=0.59, 4.82) for parous women. Use of HRT and/or OC was not associated with cartilage volume, cartilage defects or radiographic change.

CONCLUSIONS

Parity (but not use of HRT or OC) is independently associated with lower cartilage volume primarily in the tibial compartment and higher cartilage defects in the patella compartment in this population-based sample of older women.

Osteoarthritis of the knee at 3.0 T: comparison of a quantitative and a semi-quantitative score for the assessment of the extent of cartilage lesion and bone marrow edema pattern in a 24-month longitudinal study

OBJECTIVE

To compare a semi-quantitative and a quantitative morphological score for assessment of early osteoarthritis (OA) evolution.

MATERIALS AND METHODS

3.0 T MRI of the knee was performed in 60 women, 30 with early OA (each 15 with Kellgren-Lawrence grade 2 and 3) and 30 age-matched controls at baseline and at 12 and 24 months. Pathological condition was assessed with the whole-organ magnetic resonance imaging score (WORMS). Cartilage abnormalities and bone marrow edema pattern (BMEP) were also quantified using a previously introduced morphological quantitative score. These data were correlated with changes in clinical parameters and joint space width using generalized estimation equations (GEE).

RESULTS

At baseline, OA patients had significantly (p < 0.05) more and larger cartilage lesions and BMEP. During follow-up, cartilage lesions increased significantly (p < 0.05) in the patients compared with controls: WORMS showed progression only at the lateral patella, whereas the quantitative score revealed progression additionally at the trochlea and at the medial compartment. Both scores showed a significant (p < 0.05) increase in BMEP at the lateral femur in OA patients. In addition, quantitative scores of BMEP of the whole knee decreased significantly (p < 0.05) after 12 months and increased after 24 months in the patients, but showed an increase in controls at all follow-up examinations. Only weak correlations between structural imaging findings and clinical parameters were observed.

CONCLUSION

Quantitative assessment of cartilage lesions and BMEP is more sensitive to changes during the course of the disease than semi-quantitative scoring. However, structural imaging findings do not correlate well with the clinical progression of OA.

Change in knee cartilage volume in individuals completing a therapeutic exercise program for knee osteoarthritis

STUDY DESIGN

Prospective cohort study.

OBJECTIVES

To characterize knee cartilage change in individuals with knee osteoarthritis (KOA) who have completed a therapeutic exercise program.

BACKGROUND

While therapeutic exercise is frequently used successfully to improve pain and function in individuals with KOA, no studies have reported the volume of cartilage change or individual factors that may impact volume of cartilage change in those completing an exercise program for KOA.

METHODS

Thirteen individuals with KOA underwent magnetic resonance imaging to quantify cartilage volume change in the weight-bearing regions of the medial and lateral femoral condyles and the entire surface of the tibial plateaus from baseline to 1-year follow-up. Body structure and function measures were taken for body mass index, knee axis alignment, knee motion, and knee strength. Activity limitations and activity levels were also measured prior to the therapeutic exercise program, using the Western Ontario and McMaster Universities Osteoarthritis Index and the Physical Activity Scale for the Elderly. At 6 months from baseline, follow-up clinical measurements of knee strength and motion were performed. At 1 year from baseline, imaging of the knee cartilage and knee alignment were performed, and participants completed the Western Ontario and McMaster Universities Osteoarthritis Index and Physical Activity Scale for the Elderly.

RESULTS

The central region of the medial femoral condyle (cMF) had a median volume of cartilage loss of 3.8%. The other 3 knee tibiofemoral articular surfaces had minimal median cartilage volume change. Individuals were dichotomized into progressors (n = 6) and nonprogressors (n = 7), based on the standard error of measurement of cartilage volume change for the cMF. Progressors were younger, had a larger body mass index, had a higher Kellgren-Lawrence grade in the medial compartment of the knee, and had a greater increase in knee varus alignment from baseline to 1-year follow-up. The progressors also had frontal plane hip and knee kinetics during baseline gait analysis that potentially increased medial knee joint loading.

CONCLUSION

The loss of cMF cartilage volume was highly variable and the median loss of cartilage was within the range previously reported. Seven of the 13 individuals did not have cMF cartilage volume loss greater than the standard error of measurement. Change in cartilage volume of the cMF may be influenced to a greater extent by personal factors than by completion of a therapeutic exercise program. Additional research is needed to decipher the interactions among therapeutic exercise and personal characteristics that impact knee cartilage loss.

Advances in imaging of osteoarthritis and cartilage

Osteoarthritis (OA) is the most frequent form of arthritis, with major implications for individual and public health care without effective treatment available. The field of joint imaging, and particularly magnetic resonance (MR) imaging, has evolved rapidly owing to technical advances and the application of these to the field of clinical research. Cartilage imaging certainly is at the forefront of these developments. In this review, the different aspects of OA imaging and cartilage assessment, with an emphasis on recent advances, will be presented. The current role of radiography, including advances in the technology for joint space width assessment, will be discussed. The development of various MR imaging techniques capable of facilitating assessment of cartilage morphology and the methods for evaluating the biochemical composition of cartilage will be presented. Advances in quantitative morphologic cartilage assessment and semiquantitative whole-organ assessment will be reviewed. Although MR imaging is the most important modality in imaging of OA and cartilage, others such as ultrasonography play a complementary role that will be discussed briefly.

Texture analysis of cartilage T2 maps: individuals with risk factors for OA have higher and more heterogeneous knee cartilage MR T2 compared to normal controls--data from the osteoarthritis initiative

Introduction

The goals of this study were (i) to compare the prevalence of focal knee abnormalities, the mean cartilage T₂ relaxation time, and the spatial distribution of cartilage magnetic resonance (MR) T₂ relaxation times between subjects with and without risk factors for Osteoarthritis (OA), (ii) to determine the relationship between MR cartilage T₂ parameters, age and cartilage morphology as determined with whole-organ magnetic resonance imaging scores (WORMS) and (iii) to assess the reproducibility of WORMS scoring and T₂ relaxation time measurements including the mean and grey level co-occurrence matrix (GLCM) texture parameters.

Methods

Subjects with risk factors for OA (n = 92) and healthy controls (n = 53) were randomly selected from the Osteoarthritis Initiative (OAI) incidence and control cohorts, respectively. The specific inclusion criteria for this study were (1) age range 45-55 years, (2) body mass index (BMI) of 19-27 kg/m², (3) Western Ontario and McMaster University (WOMAC) pain score of zero and (4) Kellgren Lawrence (KL) score of zero at baseline. 3.0 Tesla MR images of the right knee were analyzed using morphological gradings of cartilage, bone marrow and menisci (WORMS) as well as compartment specific cartilage T₂ mean and heterogeneity. Regression models adjusted for age, gender, and BMI were used to determine the difference in cartilage parameters between groups.

Results

While there was no significant difference in the prevalence of knee abnormalities (cartilage lesions, bone marrow lesions, meniscus lesions) between controls and subjects at risk for OA, T₂ parameters (mean T₂, GLCM contrast, and GLCM variance) were significantly elevated in those at risk for OA. Additionally, a positive significant association between cartilage WORMS score and cartilage T₂ parameters was evident.

Conclusions

Overall, this study demonstrated that subjects at risk for OA have both higher and more heterogeneous cartilage T₂ values than controls, and that T₂ parameters are associated with morphologic degeneration.

The impact of MRI on the clinical management of inflammatory arthritides

In the past two decades, MRI has gained a major role in research and clinical management of patients with inflammatory arthritides, particularly in spondyloarthritis (SpA), rheumatoid arthritis (RA), and osteoarthritis (OA). MRI is regarded as the most sensitive imaging modality for detecting early SpA in young patients with inflammatory back pain and normal radiographs of the sacroiliac joints. The recently published Assessment of SpondyloArthritis International Society classification criteria for axial SpA include for the first time a positive MRI demonstrating sacroiliitis as an imaging criterion indicative of SpA together with at least one clinical feature of SpA. Recent data show that systematic assessment of sacroiliitis displayed on MRI has much greater diagnostic utility than previously reported and highlight the diagnostic relevance of structural lesions. In RA, MRI has predictive value for the development of disease in new onset undifferentiated arthritis, and MR pathology at disease onset is a highly significant predictor of radiographic erosions. Consequently MRI has been credited with an important role in the new ACR/EULAR 2010 classification criteria for RA. In OA, bone marrow edema (BME) and synovitis may serve as biomarkers in interventional trials. Treatment interventions targeting BME and synovitis observed on MRI in inflammatory arthritides may have a disease-modifying effect as these lesions are potentially reversible and have been shown to be associated with structural progression. Research should focus on the prognostic significance of MRI lesions in larger cohorts and whether adding MRI to routine care improves clinical and radiographic outcome in patients with inflammatory arthritides.

The evolution of articular cartilage imaging and its impact on clinical practice

Over the past four decades, articular cartilage imaging has developed rapidly. Imaging now plays a critical role not only in clinical practice and therapeutic decisions but also in the basic research probing our understanding of cartilage physiology and biomechanics.

Systematic review of the concurrent and predictive validity of MRI biomarkers in OA

OBJECTIVE

To summarize literature on the concurrent and predictive validity of MRI-based measures of osteoarthritis (OA) structural change.

METHODS

An online literature search was conducted of the OVID, EMBASE, CINAHL, PsychInfo and Cochrane databases of articles published up to the time of the search, April 2009. 1338 abstracts obtained with this search were preliminarily screened for relevance by two reviewers. Of these, 243 were selected for data extraction for this analysis on validity as well as separate reviews on discriminate validity and diagnostic performance. Of these 142 manuscripts included data pertinent to concurrent validity and 61 manuscripts for the predictive validity review. For this analysis we extracted data on criterion (concurrent and predictive) validity from both longitudinal and cross-sectional studies for all synovial joint tissues as it relates to MRI measurement in OA.

RESULTS

Concurrent validity of MRI in OA has been examined compared to symptoms, radiography, histology/pathology, arthroscopy, CT, and alignment. The relation of bone marrow lesions, synovitis and effusion to pain was moderate to strong. There was a weak or no relation of cartilage morphology or meniscal tears to pain. The relation of cartilage morphology to radiographic OA and radiographic joint space was inconsistent. There was a higher frequency of meniscal tears, synovitis and other features in persons with radiographic OA. The relation of cartilage to other constructs including histology and arthroscopy was stronger. Predictive validity of MRI in OA has been examined for ability to predict total knee replacement (TKR), change in symptoms, radiographic progression as well as MRI progression. Quantitative cartilage volume change and presence of cartilage defects or bone marrow lesions are potential predictors of TKR.

CONCLUSION

MRI has inherent strengths and unique advantages in its ability to visualize multiple individual tissue pathologies relating to pain and also predict clinical outcome. The complex disease of OA which involves an array of tissue abnormalities is best imaged using this imaging tool.

Responsiveness and reliability of MRI in knee osteoarthritis: a meta-analysis of published evidence

OBJECTIVE

To summarize literature on the responsiveness and reliability of MRI-based measures of knee osteoarthritis (OA) structural change.

METHODS

A literature search was conducted using articles published up to the time of the search, April 2009. 1338 abstracts obtained with this search were preliminarily screened for relevance and of these, 243 were selected for data extraction. For this analysis we extracted data on reliability and responsiveness for every reported synovial joint tissue as it relates to MRI measurement in knee OA. Reliability was defined by inter- and intra-reader intra-class correlation (ICC), or coefficient of variation, or kappa statistics. Responsiveness was defined as standardized response mean (SRM) - ratio of mean of change over time divided by standard deviation of change. Random-effects models were used to pool data from multiple studies.

RESULTS

The reliability analysis included data from 84 manuscripts. The inter-reader and intra-reader ICC were excellent (range 0.8-0.94) and the inter-reader and intra-reader kappa values for quantitative and semi-quantitative measures were all moderate to excellent (range 0.52-0.88). The lowest value (kappa=0.52) corresponded to semi-quantitative synovial scoring intra-reader reliability and the highest value (ICC=0.94) for semi-quantitative cartilage morphology. The responsiveness analysis included data from 42 manuscripts. The pooled SRM for quantitative measures of cartilage morphometry for the medial tibiofemoral joint was -0.86 (95% confidence intervals (CI) -1.26 to -0.46). The pooled SRM for the semi-quantitative measurement of cartilage morphology for the medial tibiofemoral joint was 0.55 (95% CI 0.47-0.64). For the quantitative analysis, SRMs are negative because the quantitative value, indicating a loss of cartilage, goes down. For the semi-quantitative analysis, SRMs indicating a loss in cartilage are positive (increase in score).

CONCLUSION

MRI has evolved substantially over the last decade and its strengths include the ability to visualize individual tissue pathologies, which can be measured reliably and with good responsiveness using both quantitative and semi-quantitative techniques.

Chondroitin sulphate reduces both cartilage volume loss and bone marrow lesions in knee osteoarthritis patients starting as early as 6 months after initiation of therapy: a randomised, double-blind, placebo-controlled pilot study using MRI

Objective

To determine the effect of chondroitin sulphate (CS) treatment on cartilage volume loss, subchondral bone marrow lesions (BML), synovitis and disease symptoms in patients with knee osteoarthritis (OA).

Methods

In this pilot multicentre, randomised, double-blind, controlled trial in primary knee OA, 69 patients with clinical signs of synovitis were randomised to receive CS 800 mg or placebo once daily for 6 months followed by an open-label phase of 6 months in which patients in both groups received CS 800 mg once daily. Cartilage volume and BML were assessed by MRI at baseline and at 6 and 12 months; synovial membrane thickness was assessed at baseline and at 6 months.

Results

The CS group showed significantly less cartilage volume loss than the placebo group as early as 6 months for the global knee (p=0.030), lateral compartment (p=0.015) and tibial plateaus (p=0.002), with significance persisting at 12 months. Significantly lower BML scores were found for the CS group at 12 months in the lateral compartment (p=0.035) and the lateral femoral condyle (p=0.044). Disease symptoms were similar between the two groups.

Conclusion

CS treatment significantly reduced the cartilage volume loss in knee OA starting at 6 months of treatment, and BML at 12 months. These findings suggest a joint structure protective effect of CS and provide new in vivo information on its mode of action in knee OA.

Quantification of cartilage loss in local regions of knee joints using semi-automated segmentation software: analysis of longitudinal data from the Osteoarthritis Initiative (OAI)

INTRODUCTION

Quantitative cartilage morphometry is a valuable tool to assess osteoarthritis (OA) progression. Current methodologies generally evaluate cartilage morphometry in a full or partial sub-region of the cartilage plates. This report describes the evaluation of a semi-automated cartilage segmentation software tool capable of quantifying cartilage loss in a local indexed region.

METHODS

We examined the baseline and 24-month follow-up MRI image sets of twenty-four subjects from the progression cohort of Osteoarthritis Initiative (OAI), using the Kellgren-Lawrence (KL) score of 3 at baseline as the inclusion criteria. A radiologist independently marked a single region of local thinning for each subject, and three additional readers, blinded to time point, segmented the cartilage using a semi-automated software method. Each baseline-24-month segmentation pair was then registered in 3D and the change in cartilage volume was measured.

RESULTS

After 3D registration, the change in cartilage volume was calculated in specified regions centered at the marked point, and for the entire medial compartment of femur. The responsiveness was quantified using the standardized response mean (SRM) values and the percentage of subjects that showed a loss in cartilage volume. The most responsive measure of change was SRM=-1.21, and was found for a region of 10mm from the indexed point.

DISCUSSION

The results suggest that measurement of cartilage loss in a local region is superior to larger areas and to the total plate. There also may be an optimal region size (10mm from an indexed point) in which to measure change. In principle, the method is substantially faster than segmenting entire plates or sub-regions.

Predictors of degenerative medial meniscus extrusion: radial component and knee osteoarthritis

PURPOSE

the purpose of this study was to determine the effect of a radial tear on degenerative medial meniscus posterior horn tear extrusion and to identify predictors of medial meniscus extrusion.

METHODS

we reviewed the records of 102 knees with medial meniscus posterior horn tears and degeneration that underwent a partial meniscectomy. Tears were classified as root (n = 17) and non-root (n = 85) tears, or as radial (n = 46) and non-radial (n = 56) tears. Groups were compared in terms of absolute and relative meniscal extrusion, and the proportion of knees with major (> 3 mm) extrusion. Multiple regression analysis was used to identify predictors of extrusion.

RESULTS

the radial group had greater mean absolute (4 ± 1 vs. 3 ± 1 mm, P = 0.001) and relative (31 ± 11 vs. 23 ± 12%, P = 0.031) extrusion than the non-radial group. The radial group also had a greater proportion of major extrusions than the non-radial group (74% vs. 26%; P = 0.016). In contrast, the root tear and non-root tear groups were similar in terms of mean absolute (3 ± 1 vs. 3 ± 1 mm, P = n.s.) and relative (30 ± 7 vs. 26 ± 13%; P = n.s.) extrusion and in terms of proportion with major extrusions (59 vs. 55%; P = n.s.). Extrusion was found to be associated with a similar strength with both the presence of a radial component and the preoperative Kellgren-Lawrence grade.

CONCLUSION

meniscal extrusion was greater and more severe in knees with a radial tear component than in knees without a radial component. The incidence and degree of major extrusion was similar in knees with root tears and non-root tears. A radial component and knee osteoarthritis severity were similarly predictive of absolute and relative extrusion. Meniscal extrusion in osteoarthritic knees was associated not only with degenerative meniscal tear but also with osteoarthritis severity. Therefore, arthroscopic meniscal procedures, especially meniscal repair, should be cautiously considered in patients with meniscal extrusion.

Comparison of 1-year vs 2-year change in regional cartilage thickness in osteoarthritis results from 346 participants from the Osteoarthritis Initiative

OBJECTIVE

To compare femorotibial cartilage thickness changes over a 2- vs a 1-year observation period in knees with radiographic knee osteoarthritis (OA).

METHODS

One knee of 346 Osteoarthritis Initiative (OAI) participants was studied at three time points [baseline (BL), year-1 (Y1), year-2 (Y2) follow-up]: 239 using coronal fast low angle shot (FLASH) and 107 using sagittal double echo at steady state (DESS) MR imaging. Changes in cartilage thickness were assessed in femorotibial cartilage plates and subregions, after manual segmentation with blinding to time-point.

RESULTS

The standardized response mean (SRM) of total joint cartilage thickness over 2 years was modestly higher than over 1 year (FLASH: -0.44 vs -0.32/-0.28 [first/second year]; DESS: -0.42 vs -0.39/-0.18). For the subregion showing the largest change per knee (OV1), the 2-year SRM was similar or lower (FLASH: -1.20 vs -1.22/-1.61; DESS: -1.38 vs -1.64/-1.51) than the 1-year SRM. The changes in total joint cartilage thickness were not significantly different in the first and second year (FLASH: -0.8% vs -0.7%; DESS: -1.3% vs -0.8%) and were negatively correlated. Analysis of smallest detectable changes (SDCs) revealed that only few participants displayed significant progression in both consecutive periods. The location of the subregion contributing to OV1 in each knee was highly inconsistent between the first and second year observation period.

CONCLUSIONS

The SRM of region-based cartilage thickness change in OA is modestly larger following a 2-year vs a 1-year observation period, while it is relatively similar when an OV-approach is chosen. Structural progression displays strong temporal and spatial heterogeneity at an individual knee level that should be considered when planning clinical trials.

Bone marrow lesions predict site-specific cartilage defect development and volume loss: a prospective study in older adults

Introduction

Recent evidence suggests that bone marrow lesions (BMLs) play a pivotal role in knee osteoarthritis (OA). The aims of this study were to determine: 1) whether baseline BML presence and/or severity predict site-specific cartilage defect progression and cartilage volume loss; and 2) whether baseline cartilage defects predict site-specific BML progression.

Methods

A total of 405 subjects (mean age 63 years, range 52 to 79) were measured at baseline and approximately 2.7 years later. Magnetic resonance imaging (MRI) of the right knee was performed to measure knee cartilage volume, cartilage defects (0 to 4), and BMLs (0 to 3) at the medial tibial (MT), medial femoral (MF), lateral tibial (LT), and lateral femoral (LF) sites. Logistic regression and generalized estimating equations were used to examine the relationship between BMLs and cartilage defects and cartilage volume loss.

Results

At all four sites, baseline BML presence predicted defect progression (odds ratio (OR) 2.4 to 6.4, all P < 0.05), and cartilage volume loss (-0.9 to -2.9% difference per annum, all P < 0.05) at the same site. In multivariable analysis, there was a significant relationship between BML severity and defect progression at all four sites (OR 1.8 to 3.2, all P < 0.05) and BML severity and cartilage volume loss at the MF, LT, and LF sites (β -22.1 to -42.0, all P < 0.05). Additionally, baseline defect severity predicted BML progression at the MT and LF sites (OR 3.3 to 3.7, all P < 0.01). Lastly, there was a greater increase in cartilage volume loss at the MT and LT sites when both larger defects and BMLs were present at baseline (all P < 0.05).

Conclusions

Baseline BMLs predicted site-specific defect progression and cartilage volume loss in a dose-response manner suggesting BMLs may have a local effect on cartilage homeostasis. Baseline defects predicted site-specific BML progression, which may represent increased bone loading adjacent to defects. These results suggest BMLs and defects are interconnected and play key roles in knee cartilage volume loss; thus, both should be considered targets for intervention.

Quantitative cartilage imaging in knee osteoarthritis

Quantitative measures of cartilage morphology (i.e., thickness) represent potentially powerful surrogate endpoints in osteoarthritis (OA). These can be used to identify risk factors of structural disease progression and can facilitate the clinical efficacy testing of structure modifying drugs in OA. This paper focuses on quantitative imaging of articular cartilage morphology in the knee, and will specifically deal with different cartilage morphology outcome variables and regions of interest, the relative performance and relationship between cartilage morphology measures, reference values for MRI-based knee cartilage morphometry, imaging protocols for measurement of cartilage morphology (including those used in the Osteoarthritis Initiative), sensitivity to change observed in knee OA, spatial patterns of cartilage loss as derived by subregional analysis, comparison of MRI changes with radiographic changes, risk factors of MRI-based cartilage loss in knee OA, the correlation of MRI-based cartilage loss with clinical outcomes, treatment response in knee OA, and future directions of the field.

Dynamic knee loading is related to cartilage defects and tibial plateau bone area in medial knee osteoarthritis

OBJECTIVE

To evaluate the relationship between dynamic mechanical loading, as indicated by external knee adduction moment (KAM) measures during walking, and measures of articular cartilage morphology and subchondral bone size in people with medial knee osteoarthritis (OA).

DESIGN

180 individuals with radiographic medial tibiofemoral OA participated. Peak KAM and KAM angular impulse were measured by walking gait analysis. Tibial cartilage volume and plateau bone area, and tibiofemoral cartilage defects were determined from magnetic resonance imaging using validated methods.

RESULTS

Both peak KAM (coefficient=0.42, 95% confidence interval (CI) 0.04-0.79, P=0.03) and KAM impulse (coefficient=1.79, 95% CI 0.80-2.78, P<0.001) were positively associated with the severity of medial tibiofemoral cartilage defects. KAM impulse was also associated with the prevalence of medial tibiofemoral cartilage defects (odds ratio 4.78, 95% CI 1.10-20.76, P=0.04). Peak KAM (B=0.05, 95% CI 0.01-0.09, P=0.02) and KAM impulse (B=0.16, 95% CI 0.06-0.25, P=0.002) were positively associated with medial:lateral tibial plateau bone area, and KAM impulse was also associated with medial tibial plateau bone area (B=133.7, 95% CI 4.0-263.3, P=0.04). There was no significant association between KAM measures and tibial cartilage volume.

CONCLUSION

Peak KAM and KAM impulse are associated with cartilage defects and subchondral bone area in patients with medial knee OA, suggesting that increased mechanical loading may play a role in the pathological changes in articular cartilage and subchondral bone that occur with medial knee OA.

Treatment with Tiludronic Acid Helps Reduce the Development of Experimental Osteoarthritis Lesions in Dogs with Anterior Cruciate Ligament Transection Followed by Reconstructive Surgery: A 1-Year Study with Quantitative Magnetic Resonance Imaging

Objective.

To investigate over a 1-year period in dogs that underwent extracapsular stabilization surgery (ECS) following anterior cruciate ligament (ACL) transection: whether reconstructive surgery could prevent osteoarthritis (OA) progression and whether treatment with the bisphosphonate tiludronic acid (TA) could improve the chronic evolution of OA structural changes.

Methods.

ACL transection was performed on dogs on Day 0 and ECS on Day 28. Dogs were randomly divided into 2 groups: 15 received placebo and 16 were treated with TA (2 mg/kg subcutaneous injection) on Days 14, 28, 56, and 84. Magnetic resonance images were acquired on Days −10, 26, 91, 210, and 357, and cartilage volume was quantified. At sacrifice (Day 364), cartilage from femoral condyles and tibial plateaus was macroscopically and histologically evaluated. Expression levels of MMP-1, -3, -13, ADAMTS-4, -5, BMP-2, FGF-2, IGF-1, TGF-ß1, collagen type II, and aggrecan were determined using real-time RT-PCR.

Results.

The loss of cartilage volume observed after ACL transection stabilized following ECS. Thereafter, a gradual gain occurred, with the cartilage volume loss on the tibial plateaus reduced at Day 91 (p < 0.02) and Day 210 (p < 0.001) in the TA-treated dogs. At sacrifice, TA-treated dogs presented a reduction in the severity of macroscopic (p = 0.03 for plateaus) and histologic (p = 0.07 for plateaus) cartilage lesions, had a better preserved collagen network, and showed decreased MMP-13 (p = 0.04), MMP-1 and MMP-3 levels.

Conclusion.

Our findings indicate that in dogs with ACL transection, ECS greatly prevents development of cartilage volume loss. Treatment with TA provided an additional benefit of reducing the development of OA lesions.

Magnetic resonance imaging of the knee: clinical significance of common findings

Magnetic resonance imaging (MRI) of the knee is a widely used study that accurately depicts internal derangement. However, the relevance of the findings on knee MRI to the patient's symptoms and clinical course may often be uncertain. This article discusses the clinical significance and natural history of several common findings on knee MRI examinations.

Validation of cartilage thickness calculations using indentation analysis

Different methods have been used to cross-validate cartilage thickness measurements from magnetic resonance images (MRIs); however, a majority of these methods rely on interpolated data points, regional mean and/or maximal thickness, or surface mean thickness for data analysis. Furthermore, the accuracy of MRI cartilage thickness measurements from commercially available software packages has not necessarily been validated and may lead to an under- or overestimation of cartilage thickness. The goal of this study was to perform a matching point-to-point validation of indirect cartilage thickness calculations using a magnetic resonance (MR) image data set with direct cartilage thickness measurements using biomechanical indentation testing at the same anatomical locations. Seven bovine distal femoral condyles were prepared and a novel phantom filled with dilute gadolinium solution was rigidly attached to each specimen. High resolution MR images were acquired, and thickness indentation analysis of the cartilage was performed immediately after scanning. Segmentation of the MR data and cartilage thickness calculation was performed using semi-automated software. Registration of MR and indentation data was performed using the fluid filled phantom. The inter- and intra-examiner differences of the measurements were also determined. A total of 105 paired MRI-indentation thickness data points were analyzed, and a significant correlation between them was found (r=0.88, p<0.0001). The mean difference (+/-std. dev.) between measurement techniques was 0.00+/-0.23 mm, with Bland-Altman limits of agreement of 0.45 mm and -0.46 mm. The intra- and inter-examiner measurement differences were 0.03+/-0.22 mm and 0.05+/-0.24 mm, respectively. This study validated cartilage thickness measurements from MR images with thickness measurements from indentation by using a novel phantom to register the image-based and laboratory-based data sets. The accuracy of the measurements was comparable to previous cartilage thickness validation studies in literature. The results of this study will aid in validating a tool for clinical evaluation of in-vivo cartilage thickness.

Serum and urinary biochemical markers for knee and hip-osteoarthritis: a systematic review applying the consensus BIPED criteria

CONTEXT

Molecules that are released into biological fluids during matrix metabolism of articular cartilage, subchondral bone, and synovial tissue could serve as biochemical markers of the process of osteoarthritis (OA). Unfortunately, actual breakthroughs in the biochemical OA marker field are limited so far.

OBJECTIVE

By reviewing the status of commercially available biochemical OA markers according to the "Burden of disease, Investigative, Prognostic, Efficacy of intervention, and Diagnostic" ("BIPED") classification, future use of this "BIPED" classification is encouraged and more efficient biochemical OA marker research stimulated.

DATA SOURCES

Three electronic databases [PubMed, Scopus, EMBASE (1997-May 2009)] were searched for publications on blood and urinary biochemical markers in human primary knee and hip-OA.

STUDY SELECTION

Stepwise selection of original English publications describing human studies on blood or urinary biochemical markers in primary knee or hip-OA was performed. Selected articles were fully read to determine whether biochemical markers were investigated on performance within any of the "BIPED" categories. Eighty-four relevant publications were identified.

DATA EXTRACTION

Data from relevant publications were tabulated according to the "BIPED" classification. Individual analyses within a publication were summarized in general "BIPED" scores.

DATA SYNTHESIS

An uneven distribution of scores on biochemical marker performance and heterogeneity among the publications complicated direct comparison of individual biochemical markers. Comparison of categories of biochemical markers was therefore performed instead. In general, biochemical markers of cartilage degradation were investigated most extensively and performed well in comparison with other categories of biochemical markers. Biochemical markers of bone metabolism performed less adequately. Biochemical markers of synovial tissue metabolism were not investigated extensively, but performed quite well.

CONCLUSIONS

Specific biochemical markers and categories of biochemical markers as well as their nature, origin and metabolism, need further investigation. International standardization of future investigations should be pursued to obtain more high-quality, homogenous data on the full spectrum of biochemical OA markers.

Targeting subchondral bone for treating osteoarthritis: what is the evidence?

Over the past few decades, significant progress has been made with respect to new concepts about the pathogenesis of osteoarthritis (OA). This article summarises some of the knowledge we have today on the involvement of the subchondral bone in OA. It provides substantial evidence that changes in the metabolism of the subchondral bone are an integral part of the OA disease process and that these alterations are not merely secondary manifestations, but are part of a more active component of the disease. Thus, a strong rationale exists for therapeutic approaches that target subchondral bone resorption and/or formation, and data evaluating the drugs targeting bone remodelling raise the hope that new treatment options for OA may become available.

Most patients gain weight in the 2 years after total knee arthroplasty: comparison to a healthy control group

OBJECTIVE

While joint arthroplasty improves the functional ability of persons with severe knee osteoarthritis (OA), the long-term effects of surgical intervention on body mass have not been evaluated. The objective of this study was to determine if a reduction in body mass index (BMI) was present following unilateral total knee arthroplasty (TKA) compared to an age-matched healthy control group who did not have surgery.

METHOD

One hundred and six adults with unilateral, end-stage knee OA and thirty-one persons without knee pain participated in the prospective longitudinal study. Subjects with OA underwent primary unilateral TKA and received post-operative out-patient physical therapy. Height, weight, quadriceps strength and self-perceived functional ability were measured at baseline and at a 2-year follow-up.

RESULTS

There was a significant interaction effect between body mass over time and subject group (P=0.017). BMI showed a significant increase over 2 years for the surgical group (P<0.001), but not for the control group (P=0.842). Sixty-six percent of the persons in the surgical group gained weight over the 2 years with an average weight gain of 6.4 kg, or 14 pounds, 2 years after their initial physical therapy visit. Educational level, marital status, income level and activity level prior to surgery were not related to post-surgical weight gain.

CONCLUSION

The majority of subjects gain weight after surgery and this cannot be attributed to the effects of aging. Weight gain after TKA should be treated as an independent concern and management of orthopedic impairments will not result in weight loss. Post-operative care should include access to nutrition or weight management professionals in addition to medical and physical therapy services.

Osteoarthritis may not be a one-way-road of cartilage loss--comparison of spatial patterns of cartilage change between osteoarthritic and healthy knees

OBJECTIVE

To explore whether longitudinal change in cartilage thickness in femorotibial subregions of knees with radiographic osteoarthritis (ROA) differs from that in healthy knees.

METHODS

3T coronal magnetic resonance (MR) images were acquired in 152 women at seven clinical centers at baseline (BL) and 24 months. Knees from 75 women with signs of ROA in either anterior-posterior or Lyon schuss radiographs were compared with those from 77 asymptomatic healthy controls without ROA to identify knees showing greater change in cartilage thickness than expected based on observations in healthy knees. The femorotibial cartilage thickness was determined in BL and follow-up MR images across five tibial and three femoral subregions in the medial/lateral compartment, respectively.

RESULTS

A substantial portion of knees with ROA were classified as having longitudinal cartilage thinning (28%) or thickening (20%) in at least one medial femorotibial subregion based on comparisons to longitudinal changes observed in healthy knees; only 5% showed both subregional thinning and thickening across (different) medial subregions at the same time. Whereas the estimated proportion of Kellgren Lawrence grade (KLG) 3 knees (n=28) with significant medial cartilage thinning (46%) was substantially greater than that with cartilage thickening (18%), the estimated percentages of KLG2 knees (n=30) with significant medial thinning (20%) and thickening (23%) were similar.

CONCLUSION

This exploratory study indicates that OA may not be a one-way-road of cartilage loss. Subregional analysis suggests that, compared with healthy knees, cartilage changes in ROA may occur in both directions. Medial femorotibial cartilage thickening was observed as frequently as cartilage thinning in KLG2 knees.

Magnetic resonance imaging-based semiquantitative and quantitative assessment in osteoarthritis

Whole organ magnetic resonance imaging (MRI)-based semiquantitative (SQ) assessment of knee osteoarthritis (OA), based on reliable scoring methods and expert reading, has become a powerful research tool in OA. SQ morphologic scoring has been applied to large observational cross-sectional and longitudinal epidemiologic studies as well as interventional clinical trials. SQ whole organ scoring analyzes all joint structures that are potentially relevant as surrogate outcome measures of OA and potential disease modification, including cartilage, subchondral bone, osteophytes, intra- and periarticular ligaments, menisci, synovial lining, cysts, and bursae. Resources needed for SQ scoring rely on the MRI protocol, image quality, experience of the expert readers, method of documentation, and the individual scoring system that will be applied. The first part of this article discusses the different available OA whole organ scoring systems, focusing on MRI of the knee, and also reviews alternative approaches. Rheumatologists are made aware of artifacts and differential diagnoses when applying any of the SQ scoring systems. The second part focuses on quantitative approaches in OA, particularly measurement of (subregional) cartilage loss. This approach allows one to determine minute changes that occur relatively homogeneously across cartilage structures and that are not apparent to the naked eye. To this end, the cartilage surfaces need to be segmented by trained users using specialized software. Measurements of knee cartilage loss based on water-excitation spoiled gradient recalled echo acquisition in the steady state, fast low-angle shot, or double-echo steady-state imaging sequences reported a 1% to 2% decrease in cartilage thickness annually, and a high degree of spatial heterogeneity of cartilage thickness changes in femorotibial subregions between subjects. Risk factors identified by quantitative measurement technology included a high body mass index, meniscal extrusion and meniscal tears, knee malalignment, advanced radiographic OA grade, bone marrow alterations, and focal cartilage lesions.

An open-label pilot study evaluating by magnetic resonance imaging the potential for a disease-modifying effect of celecoxib compared to a modelized historical control cohort in the treatment of knee osteoarthritis

OBJECTIVES

The aim of the study was to evaluate by quantitative magnetic resonance imaging the effect of celecoxib 200 mg daily on cartilage volume loss over 12 months in knee osteoarthritis.

METHODS

The primary outcome of this study was to evaluate cartilage volume loss in the medial compartment of the knee (femoral condyle and tibial plateau) assessed by quantitative magnetic resonance imaging on subjects receiving continuous treatment with celecoxib 200 mg daily for 12 months compared with a modelized historical control cohort, as expressed by the percentage loss from baseline. Safety of the medication was also assessed. Comparison of the observed volume loss to the expected loss was evaluated by a multivariate linear regression model based on a historical cohort.

RESULTS

For the primary outcome, the 95% confidence intervals for the mean observed celecoxib cohort joint medial compartment cartilage volume loss (6.81% [6.01; 7.60]) and mean predicted loss (modelized historical cohort) (5.65% [5.10; 6.19]) overlap, indicating no significant difference and hence no effect of celecoxib on the medial compartment cartilage volume loss. Similar findings were demonstrated for the lateral compartment cartilage loss. The safety data reported several minor adverse events similar to those typically seen in a 1-year clinical trial.

CONCLUSIONS

Although celecoxib was demonstrated to be safe for knee osteoarthritis at a 200 mg daily dose, it did not provide a protective effect on knee cartilage loss. Cohort modelization is an efficient and unbiased way to provide a comparator group for the assessment of novel treatments when classic head-to-head randomized controlled trials are not feasible.

Magnetic resonance imaging-based cartilage loss in painful contralateral knees with and without radiographic joint space narrowing: Data from the Osteoarthritis Initiative

OBJECTIVE

To determine by magnetic resonance imaging (MRI), whether knees with advanced radiographic disease (medial joint space narrowing [mJSN]) encounter greater longitudinal cartilage loss than contralateral knees with earlier disease (no or less mJSN).

METHODS

Participants were selected from 2,678 cases in the Osteoarthritis Initiative, based on exhibition of bilateral pain, body mass index >25 (kg/m(2)), mJSN in 1 knee, no or less mJSN in the contralateral knee, and no lateral JSN in both knees. Eighty participants (mean +/- SD age 60.6 +/- 9.1 years) fulfilled these criteria. Medial tibial and femoral cartilage morphology was analyzed from the baseline and the 1-year followup MRI (sagittal double echo at steady state by 3.0T) of both knees by experienced readers blinded to the time point and mJSN status.

RESULTS

Knees with more radiographic mJSN displayed greater medial cartilage loss (-80 mum) assessed by MRI than contralateral knees with less mJSN (-57 mum). The difference reached statistical significance in participants with an mJSN grade of 2 or 3 (P = 0.005-0.08), but not in participants with an mJSN grade of 1 (P = 0.28-0.98). In knees with more mJSN, cartilage loss increased with higher grades of mJSN (P = 0.003 in the medial femur). Knees with an mJSN grade of 2 or 3 displayed greater cartilage loss in the weight-bearing medial femur than in the posterior femur or in the medial tibia (P = 0.048).

CONCLUSION

Knees with advanced mJSN displayed greater cartilage loss than contralateral knees with less mJSN. These data suggest that radiography can be used to stratify fast structural progressors, and that MRI cartilage thickness loss is more pronounced at advanced radiographic disease stage.

Tibiofemoral joint osteoarthritis: risk factors for MR-depicted fast cartilage loss over a 30-month period in the multicenter osteoarthritis study

PURPOSE

To assess baseline factors that may predict fast tibiofemoral cartilage loss over a 30-month period.

MATERIALS AND METHODS

The Multicenter Osteoarthritis (MOST) study is a longitudinal study of individuals who have or who are at high risk for knee osteoarthritis. The HIPAA-compliant protocol was approved by the institutional review boards of all participating centers, and written informed consent was obtained from all participants. Magnetic resonance (MR) images were read according to the Whole-Organ Magnetic Resonance Imaging Score (WORMS) system. Only knees with minimal baseline cartilage damage (WORMS < or = 2.5) were included. Fast cartilage loss was defined as a WORMS of at least 5 (large full-thickness loss, less than 75% of the subregion) in any subregion at 30-month follow-up. The relationships of age, sex, body mass index (BMI), ethnicity, knee alignment, and several MR features (eg, bone marrow lesions, meniscal damage and extrusion, and synovitis or effusion) to the risk of fast cartilage loss were assessed by using a multivariable logistic regression model.

RESULTS

Of 347 knees, 90 (25.9%) exhibited cartilage loss, and only 20 (5.8%) showed fast cartilage loss. Strong predictors of fast cartilage loss were high BMI (adjusted odds ratio [OR], 1.11; 95% confidence interval [CI]: 1.01, 1.23), the presence of meniscal tears (adjusted OR, 3.19; 95% CI: 1.13, 9.03), meniscal extrusion (adjusted OR, 3.62; 95% CI: 1.34, 9.82), synovitis or effusion (adjusted OR, 3.36; 95% CI: 0.91, 12.4), and any high-grade MR-depicted feature (adjusted OR, 8.99; 95% CI: 3.23, 25.1).

CONCLUSION

In participants with minimal baseline cartilage damage, the presence of high BMI, meniscal damage, synovitis or effusion, or any severe baseline MR-depicted lesions was strongly associated with an increased risk of fast cartilage loss. Patients with these risk factors may be ideal subjects for preventative or treatment trials.

OARSI-OMERACT definition of relevant radiological progression in hip/knee osteoarthritis

BACKGROUND

Joint space width (JSW) evaluated in millimeters on plain X-rays is the currently optimal recognized technique to evaluate osteoarthritis (OA) structural progression. Data obtained can be presented at the group level (e.g., mean+/-standard deviation of the changes). Such presentation makes difficult the interpretation of the clinical relevance of the reported results. Therefore, a presentation at the individual level (e.g., % progressors) seems more attractive but requires to determining a cut-off. Several methodologies have been proposed to define cut-offs in JSW: arbitrary chosen cut-off, cut-off based on the validity to predict a relevant end-point such as the requirement of total articular replacement or cut-off based on the measurement error such as smallest detectable difference (SDD).

OBJECTIVES

The objective of this OARSI-OMERACT initiative was to define a cut-off evaluated in millimeters on plain X-rays above which a change in JSW could be considered as relevant in patients with hip and knee OA.

METHODS

The first step consisted in a systematic literature research performed using Medline database up to July 2007 to obtain all manuscripts published between 1990 and 2007 reporting a cut-off value in JSW evaluated in millimeters at either the knee or hip level. The second step consisted in a consensus based on the best knowledge of the 11 experts with the support of the available evidence.

RESULTS

Among the 506 articles selected by the search, 47 articles reported cut-off of JSW in millimeters. There was a broad heterogeneity in cut-off values, whatever the methodologies or the OA localization considered (e.g., from 0.12 to 0.84 mm and from 0.22 to 0.78 mm for Knee (seven studies) and hip (seven studies), respectively when considering the data obtained based on the reliability). Based on the data extracted in the literature, the expert committee proposed a definition of relevant change in JSW based on plain X-rays, on an absolute change of JSW in millimeters and on the measurement error e.g., calculation of the SDD using the Bland and Altman technique. The results of the analysis of JSW should be expressed in terms of a dichotomous variable (e.g., progressors yes/no): a patient with a change in JSW during the study over such SDD will fulfill the definition of "progressor". Moreover, the pilot study aimed at evaluating the measurement error should be designed to reflect the different characteristics of the primary study in which the analysis of the radiological findings will be based on (patient's characteristics, centers characteristics, readers).

CONCLUSION

This initiative based on both an Evidence Based Medicine (Systematic Literature Research) and Expert Opinion approach resulted in a proposal of definition of relevant radiological progression in OA to be used as end-point in clinical trials and also recommendations on the conduct of the reliability study allowing such definition.

Imaging the painful osteoarthritic knee joint: what have we learned?

Pain in the peripheral joints is an increasingly common problem, resulting in significant patient disability and health-care expenditure. Osteoarthritis (OA), a syndrome of joint pain with associated structural changes, is the most prevalent joint disease, yet the etiology of pain in OA is not entirely clear. Traditional assessment of the structure-pain relationship in knee OA has relied on conventional radiography, which has several limitations, not least the discrepancy between symptoms and radiographic findings. MRI has the capability to visualize all the structures within the knee joint, and there is a growing body of work using MRI to examine the correlation between structural findings and symptoms. In large cohort studies, synovial hypertrophy, synovial effusions, and abnormalities in the subchondral bone have been associated with knee pain. Advances in our understanding of the etiology of pain in OA will assist in the identification of further targets for treatment of this common and painful disease.

Relationship of compartment-specific structural knee status at baseline with change in cartilage morphology: a prospective observational study using data from the osteoarthritis initiative

INTRODUCTION

The aim was to investigate the relationship of cartilage loss (change in medial femorotibial cartilage thickness measured with magnetic resonance imaging (MRI)) with compartment-specific baseline radiographic findings and MRI cartilage morphometry features, and to identify which baseline features can be used for stratification of fast progressors.

METHODS

An age and gender stratified subsample of the osteoarthritis (OA) initiative progression subcohort (79 women; 77 men; age 60.9 +/- 9.9 years; body mass index (BMI) 30.3 +/- 4.7) with symptomatic, radiographic OA in at least one knee was studied. Baseline fixed flexion radiographs were read centrally and adjudicated, and cartilage morphometry was performed at baseline and at one year follow-up from coronal FLASH 3 Tesla MR images of the right knee.

RESULTS

Osteophyte status at baseline was not associated with medial cartilage loss. Knees with medial joint space narrowing tended to show higher rates of change than those without, but the relationship was not statistically significant. Knees with medial femoral subchondral bone sclerosis (radiography), medial denuded subchondral bone areas (MRI), and low cartilage thickness (MRI) at baseline displayed significantly higher cartilage loss than those without, both with and without adjusting for age, sex, and BMI. Participants with denuded subchondral bone showed a standardized response mean of up to -0.64 versus -0.33 for the entire subcohort.

CONCLUSIONS

The results indicate that radiographic and MRI cartilage morphometry features suggestive of advanced disease appear to be associated with greater cartilage loss. These features may be suited for selecting patients with a higher likelihood of fast progression in studies that attempt to demonstrate the cartilage-preserving effect of disease-modifying osteoarthritis drugs.

Serum levels of vitamin D, sunlight exposure, and knee cartilage loss in older adults: the Tasmanian older adult cohort study

OBJECTIVE

To determine the associations between serum levels of vitamin D, sunlight exposure, and knee cartilage loss cross-sectionally and longitudinally in older adults.

METHODS

A total of 880 randomly selected subjects (mean age 61 years [range 51-79 years], 50% women) were studied at baseline, and 353 of these subjects were studied 2.9 years later. Serum levels of 25-hydroxyvitamin D (25[OH]D) were assessed by radioimmunoassay, and sunlight exposure was assessed by questionnaire. T1-weighted fat-suppressed magnetic resonance imaging (MRI) of the right knee was performed to determine knee cartilage volume and defects. Knee radiographic osteoarthritis (OA) and knee pain were also assessed.

RESULTS

The mean 25(OH)D serum level was 52.8 nmoles/liter at baseline (range 13-119 nmoles/liter). Winter sunlight exposure and serum 25(OH)D level were both positively associated with medial and lateral tibial cartilage volume, and a serum 25(OH)D level<50 nmoles/liter was associated with increased medial tibiofemoral joint space narrowing (all P<0.05). Longitudinally, baseline serum 25(OH)D level predicted change in both medial and lateral tibial cartilage volume (beta=+0.04% per annum per nmole/liter for both; P<0.05), and change in serum 25(OH)D level was positively associated with change in medial tibial cartilage volume. These associations were consistent in subjects with radiographic OA and knee pain and/or in women, but not in men or in subjects without radiographic OA or knee pain.

CONCLUSION

Sunlight exposure and serum 25(OH)D levels are both associated with decreased knee cartilage loss (assessed by radiograph or MRI). This is best observed using the whole range of 25(OH)D levels rather than predefined cut points and implies that achieving vitamin D sufficiency may prevent and/or retard cartilage loss in knee OA.

Osteoarthritis: current role of imaging

Osteoarthritis (OA) is the most prevalent joint disease; it is increasingly common in the aging population of Western society and has a major health economic impact. Despite surgery and symptom-oriented approaches there is no efficient treatment. Conventional radiography has played a role in the past in confirming diagnosis and demonstrating late bony changes and joint space narrowing. MRI has become the method of choice in large research endeavors and may become important for individualized treatment planning. This article focuses on radiography and MRI, with insight into other modalities, such as ultrasound, scintigraphy, and CT. Their role in OA diagnosis, follow-up, and research is discussed.

Obesity and osteoarthritis: disease genesis and nonpharmacologic weight management

The mechanisms by which obesity affects osteoarthritis (OA) are of great concern to osteoarthritis researchers and clinicians who manage this disease. Inflammation and joint loads are pathways commonly believed to cause or to exacerbate the disease process. This article reviews the physiologic and mechanical consequences of obesity in older adults who have knee OA, the effects of long-term exercise and weight-loss interventions, the most effective nonpharmacologic treatments for obesity, and the usefulness and feasibility of translating these results to clinical practice.

Effects of exercise vs experimental osteoarthritis on imaging outcomes

OBJECTIVE

To identify changes in imaging outcomes in a controlled model of osteoarthritis (OA) vs exercise.

METHOD

Sixteen 2-year-old horses were randomly assigned to an exercise control (n=8) or an exercise OA (n=8) group. All horses had middle carpal joints arthroscopically explored and an osteochondral fragment was induced in one middle carpal joint of the OA group. All horses were treadmill exercised for the duration of the study (91 days). Clinical, radiographic, nuclear scintigraphic, computed tomographic and magnetic resonance imaging (MRI) examinations were performed and outcomes of these were compared between groups. Imaging results were correlated to clinical, biomarker and gross pathologic results.

RESULTS

The OA group had significant increases in clinical outcomes and most imaging parameters. Specifically, the OA group showed significant increases in radiographic lysis and nuclear scintigraphic uptake. There was very little change in subchondral bone density, but a significant change in subchondral bone edema. Radiographic lysis, radial carpal bone edema and nuclear scintigraphy were strongly correlated with clinical changes and radial carpal bone edema was strongly correlated with changes in Type I and Type II collagen found in the synovial fluid.

CONCLUSIONS

OA induced significant changes in imaging parameters beyond the adaptation seen with exercise. Bone edema detected with MRI was closely correlated with collagen biomarkers detected in the synovial fluid.

Analysis of the precision and sensitivity to change of different approaches to assess cartilage loss by quantitative MRI in a longitudinal multicentre clinical trial in patients with knee osteoarthritis

Introduction

Cartilage thickness and volume loss measurements using quantitative magnetic resonance imaging (qMRI) are suggested to detect significant cartilage changes over short time intervals. We aimed to compare these two different approaches looking at the global knee and subregions, using data from an osteoarthritis (OA) multicentre randomised clinical trial.

Methods

Three hundred and fifty-five patients with symptomatic knee OA were recruited for a two-year, double-blind, randomised clinical trial evaluating the effect of 200 mg licofelone twice daily and 500 mg naproxen twice daily on cartilage loss, and 301 patients had baseline MRI. MRIs were performed at baseline, 6, 12 and 24 months. Cartilage volume and thickness in the global joint, medial and lateral compartments, and central weight-bearing subregions of the medial and lateral femoral condyles and tibial plateaus were analysed. Data were analysed for the mean value imputed for intent-to-treat (ITT-MVI) and statistical analyses were performed using two-sample Student's t-test.

Results

Cartilage mean thickness loss in the global joint, lateral and medial compartments, as well as in medial compartments stratified according to patients with or without meniscal extrusion, was significantly less in the licofelone compared with the naproxen group at 12 and 24 months. Interestingly, these data were similar to those found when using cartilage volume loss as an outcome. Although greater cartilage volume and mean thickness loss was seen in central weight-bearing subregions of the medial and lateral compartments compared with the whole compartment and also in patients with meniscal lesions/extrusion, suggesting good sensitivity to change, its high standard deviation precluded for the condyles a high statistical power and abrogated statistically significant differences between the treatment groups.

Conclusions

These data demonstrate that both the measurement of cartilage thickness and that of cartilage volume provide the same level of sensitivity to estimate cartilage loss in a clinical trial. However, the potential of gaining statistical power with the use of thickness/volume change in knee subregions as an outcome seems negated by high inter-patient variability. Moreover, there is no superiority in statistical power by selecting patients with meniscal extrusion.