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ABSTRACT: OBJECTIVE: To quantitatively evaluate position, size, and shape of the menisci in subjects with radiographic knee osteoarthritis (OA) compared to subjects free of OA using magnetic resonance (MR) imaging. METHODS: We studied right knees from 39 Osteoarthritis Initiative participants (24 women, 15 men; mean age 59.6±8.7 years) with medial compartment radiographic tibiofemoral OA (Kellgren Lawrence grade 2 or 3). We matched them individually by age, sex and body height with right knees of subjects without knee OA and without risk factors for knee OA as references. One observer performed manual segmentation of the tibial plateau and the medial and lateral meniscus based on coronally reconstructed DESSwe focusing on 5 central 3T MR images. RESULTS: Meniscal coverage of the medial tibial plateau was less in OA knees (40.5% vs. 49.8%; p<0.0001), the medial meniscus body showed more extrusion (2.64 vs. 0.53mm; p<0.0001) and the peripheral margin had a more convex shape, i.e., bulged more (mean 0.61 vs. 0.27mm, p<0.0001). The thickness or volume of the medial meniscus body of OA knees did not differ substantially. In contrast the lateral meniscus body had a larger volume (mean 266 vs. 224mm(3) ; p=0.0005), extruded more (mean 1.16 vs. -1.01mm; p<0.0001) and the external margin bulged more (mean 0.53 vs. 0.35mm; p<0.0001)in OA than in reference knees. CONCLUSIONS: The study provides evidence for altered meniscal position and shape (i.e.,more bulging in OA knees) in both compartments in medial compartment knee OA. These changes may be important features of OA pathogenesis and/or disease consequences. © 2013 American College of Rheumatology.
Arthritis & Rheumatism 03/2013; · 7.87 Impact Factor
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ABSTRACT: OBJECTIVE: To test whether cross-sectional or longitudinal measures of thigh muscle isometric strength differ between knees with and without subsequent radiographic progression of knee osteoarthritis (KOA), with particular focus on pre-osteoarthritic female knees (knees with risk factors but without definite radiographic KOA). METHODS: Of 4796 Osteoarthritis Initiative participants, 2835 knees with Kellgren Lawrence grade (KLG) 0-3 had central X-ray readings, annual quantitative joint space width (JSW) and isometric muscle strength measurements (Good strength chair). Separate slope ANCOVA models were used to determine differences in strength between "progressor" and "non-progressor" knees, after adjusting for age, body mass index, and pain. RESULTS: 466 participant knees exceeded the smallest detectable JSW change during each of two observation intervals (year 2→4 and year 1→3) and were classified as progressors (213 women, 253 men; 128 KLG0/1, 330 KLG2/3); 946 participant knees did not exceed this threshold in either interval and were classified as non-progressors (588 women, 358 from men; 288KLG0/1, 658KLG2/3). Female progressor knees, including those with KLG0/1, tended to have lower extensor and flexor strength at year2 and at baseline than those without progression, but the difference was not significant after adjusting for confounders. No significant difference was observed in longitudinal change of muscle strength (baseline→year2) prior to radiographic progression. No significant differences were found for muscle strength in men, and none for change in strength concomitant with progression. CONCLUSION: This study provides no strong evidence that (changes in) isometric muscle strength precedes or is associated with structural (radiographic) progression of KOA.
Osteoarthritis and Cartilage 03/2013; · 3.90 Impact Factor
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ABSTRACT: OBJECTIVE: To compare cross-sectional and longitudinal side-differences in thigh muscle anatomical cross-sectional areas (ACSAs), strength, and specific strength (strength/ACSA) between knees with painful early vs. painful advanced radiographic osteoarthritis in the same person. METHODS: 44 of2678 Osteoarthritis Initiativeparticipants (31 women; 13 men) met inclusion criteria of bilateral frequent knee pain, medial joint space narrowing (mJSN) in one knee, and no medial (or lateral) JSN in the contralateral knee. Thigh muscle ACSAs of the quadriceps, hamstrings, adductors, and individual quadriceps heads at consistent locations were determined using MRI. Isometric muscle strength was determined in extension/flexion (Good Strength Chair, MetiturOy, Finland). Baseline quadriceps ACSA and strength were considered primary, and longitudinal changes of these secondary endpoints (paired t-tests). RESULTS: No significant side-differences in quadriceps (or other thigh muscles) ACSAs, strength, or specific strength were observed between mJSN vs. no-JSN knees, nor between specific mJSN strata and contra-lateral no-JSN knees, neither in men nor women. Two-year longitudinal changes in thigh muscle ACSA, and strength were small (≤5.2%) and did not differ significantly between mJSN and no-JSN knees. CONCLUSION: In the context of previous findings that side differences in pain are associated with side differences in quadriceps ACSAs, the current results suggest that quadriceps (and other thigh muscle) properties are not independently associated with radiographic disease status (JSN), once knees have reached frequent pain status. Further, our longitudinal findings indicate that a more advanced radiographic stage of knee osteoarthritis is not necessarily associated with a longitudinal decline in muscle function. © 2013 by the American College of Rheumatology.
Arthritis care & research. 02/2013;
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ABSTRACT: OBJECTIVE: Minimum radiographic joint space width (mJSW) represents the FDA standard for demonstrating structural therapeutic benefits for knee osteoarthritis (KOA), but only shows moderate responsiveness (sensitivity to change). We directly compare the responsiveness of MRI-based cartilage thickness and JSW measures from fixed-flexion radiography (FFR) and explore the correlation of region-matched changes between both methods. METHODS: 967 knees of Osteoarthritis Initiative participants with radiographic KOA were studied: 445 over one year with coronal FLASH MRI and FFR, and 375/522 over one /two years with sagittal DESS MRI and FFR. Standardized response means (SRM) of cartilage thickness and mJSW were compared using the sign-test. RESULTS: With FLASH MRI, SRM was -0.28 for medial compartment (MFTC) cartilage loss vs. -0.15 for mJSW, and -0.32 vs. -0.22 for the most sensitive MRI subregion (central MFTC) vs. the most sensitive fixed location JSW(X=0.25) . With DESS MRI, one-year SRM was -0.34 for MFTC vs. -0.22 for mJSW and -0.44 vs. -0.28 for central MFTC vs. JSW(X=0.225). Over two years, the SRM was significantly greater for MFTC than for mJSW (-0.43 vs. -0.31, p=0.017) and for central MFTC than for JSW(X=0.225) (-0.51 vs. -0.44, p<0.001). Correlations between changes in spatially matched MRI subregions and fixed location JSW were not consistently higher (r=0.10-0.51) than those between non-matched locations (r=0.15-0.50). CONCLUSIONS: MRI displays greater responsiveness in KOA than JSW FFR-based JSW, with the greatest SRM observed in the central medial femorotibial compartment. Fixed-location radiographic measures appear not capable of determining the spatial distribution of femorotibial cartilage loss.
Osteoarthritis and Cartilage 11/2012; · 3.90 Impact Factor
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ABSTRACT: OBJECTIVE: Estimate the frequency and spatial location of rapid femorotibial cartilage thinning or thickening in knees with, or at risk of, osteoarthritis and examine their association with clinical and radiographic covariates. DESIGN: Knee cartilage thickness change over 12 months was measured using magnetic resonance imaging in the right knee of 757 Osteoarthritis Initiative (OAI) participants that had radiographic findings of osteophytes or joint space narrowing. Thickness changes in individual knees were classified as having rapid thinning or thickening or no detectable OA-related change when compared to asymptomatic OAI Control cohort knees. RESULTS: Cartilage thinning, found in 18.5% of subjects, was more frequent in knees with OAI calculated Kellgren-Lawrence Grade (cKLG)>2 (p<0.001) and with frequent pain (p=0.047). No link was found between body mass index, sex, and age and cartilage thinning (p>0.15). The percent of knees with thickening was small (4.4%), but greater in knees with frequent pain (p=0.02). Rapid thinning was most common in the central (36.4%) and external (32.1%) subregions of the medial weight-bearing femur. Mean cartilage loss in rapidly thinning subregions ranged from 11.2%/y to 24.6%/y. Knees with cKLG>2, but classified as having no detectable OA-related change had mean cartilage loss rates significantly >0 (0.4%/y to 1.3%/y) in 10 subregions. CONCLUSION: Most observed subregional changes in OA knees were indistinguishable from changes found in an asymptomatic cohort, but a fraction of subregions showed rapid progression. The relative frequency of rapid thinning increases when cKLG>2, a classification closely associated with joint space narrowing and/or frequent knee pain are present.
Osteoarthritis and Cartilage 10/2012; · 3.90 Impact Factor
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ABSTRACT: OBJECTIVE: To compare unbiased estimates of short- vs long-term cartilage loss in osteoarthritic knees. METHOD: 441 knees [216 Kellgren Lawrence (KL) grade 2, 225 KL grade 3] from participants of the Osteoarthritis Initiative were studied over a 4-year period. Femorotibial cartilage thickness was determined using 3 T double echo steady state magnetic resonance imaging, the readers being blinded to time points. Because common measurement time points bias correlations, short-term change (year-1 to year-2: Y1 → Y2) was compared with long-term change (baseline to year-4: BL → Y4), and initial (BL → Y1) with subsequent (Y2 → Y4) observation periods. RESULTS: The mean femorotibial cartilage thickness change (standardized response mean) was -1.2%/-0.8% (-0.42/-0.28) over 1 (BL → Y1/Y1 → Y2), -2.1%/-2.5% (-0.56/-0.55) over 2 (BL → Y2/Y2 → Y4), -3.3% (-0.63) over 3 (Y1 → Y4), and -4.5% (-0.78) over 4 years. Spearman correlations were 0.33 for Y1 → Y2 vs BL → Y4, and 0.17 for BL → Y1 vs Y2 → Y4 change. Percent agreement between knees showing progression during Y1 → Y2 vs BL → Y4 was 59%, and 64% for BL → Y1 vs Y2 → Y4. The area under the receiver operating characteristic curve was 0.66 for using Y1 → Y2 to predict BL → Y4, and 0.59 for using BL → Y1 to predict Y2 → Y4 change. CONCLUSION: Weak to moderate correlations and agreement were observed between individual short- vs long-term cartilage loss, and between initial and subsequent observation periods. Hence, longer observation periods are recommended to achieve robust results on cartilage loss in individual knees. At cohort and subcohort level (e.g., KLG3 vs KLG2 knees), the mean cartilage loss increased almost linearly with the length of the observation period and was constant throughout the study.
Osteoarthritis and Cartilage 07/2012; 20(11):1250-1257. · 3.90 Impact Factor
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ABSTRACT: Osteoarthritis (OA) is the most common joint disorder. The Osteoarthritis Initiative (OAI) is a multicentre, longitudinal, prospective observational cohort study of knee OA that aims to provide publicly accessible clinical datasets, images and biospecimens, to enable researchers to investigate factors that influence the onset and development of OA, and evaluate biomarkers that predict and track the course of the disease. In this Perspectives, we describe the rationale and design of the OAI and its cohort, discuss imaging protocols and summarize image analyses completed to date. We include descriptive analyses of publicly available longitudinal (2-year) data of changes in cartilage thickness in a core sample of 600 knees from 590 participants in the OAI progression subcohort. Furthermore, we describe published methodological and applied imaging research that has emerged from OAI pilot studies and OAI data releases, and how these studies might contribute to clinical development of biomarkers for assessing the efficacy of intervention trials.
Nature Reviews Rheumatology 07/2012; 8(10):622-30. · 8.39 Impact Factor
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Felix Eckstein,
C Kent Kwoh,
Robert M Boudreau,
Zhijie Wang,
Michael J Hannon,
Sebastian Cotofana,
Martin I Hudelmaier, Wolfgang Wirth,
Ali Guermazi,
Michael C Nevitt,
Markus R John,
David J Hunter
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ABSTRACT: OBJECTIVE: Knee osteoarthritis commonly requires joint replacement, substantially reduces quality of life and increases healthcare utilisation and costs. This study aimed to identify whether quantitative measures of articular cartilage structure predict knee replacement, and to establish their utility as outcomes in clinical trials of disease-modifying therapy. METHODS: A nested case-control study was performed in Osteoarthritis Initiative participants, a multicentre observational cohort of 4796 participants with or at risk of knee osteoarthritis. 127 knees were replaced between baseline and 4 years follow-up, and one control knee per case matched for baseline radiographic disease stage (Kellgren-Lawrence grade; KLG), gender and age. Quantitative cartilage measures were obtained from 3 T magnetic resonance images at the exam before knee replacement, and longitudinal change during the previous 12 months when available (n=110). RESULTS: Cartilage thickness loss in the central and total medial femorotibial compartment (primary and secondary predictor variables) was significantly greater in case than control knees (AUC=0.59/0.58). Differences in cartilage loss were greater at earlier than later radiographic disease stages (p<0.01 for interaction with KLG). Cartilage thickness loss in the central tibia was the most predictive longitudinal measure (AUC=0.64). Denuded bone areas in the medial femur were the most predictive and discriminatory cross-sectional measure between case and control knees (AUC=0.66). CONCLUSIONS: This study demonstrates the predictive value of quantitative, MRI-based measures of cartilage for the clinically relevant endpoint of knee replacement, providing support for their utility in clinical trials to evaluate the effectiveness of structure-modifying intervention.
Annals of the rheumatic diseases 06/2012; · 8.11 Impact Factor
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ABSTRACT: OBJECTIVE: To determine whether the presence of definite osteophytes (in absence of joint space narrowing [JSN]) by radiograph is associated with (subregional) increases in cartilage thickness, in a within-person, between-knee cross-sectional comparison of participants in the Osteoarthritis Initiative (OAI). Based on previous results, external medial (ecMF) and external lateral weight-bearing femoral (ecLF) subregions were selected as primary endpoints. METHODS: Both knees of 61 (of 4798) OAI participants displayed definite tibial or femoral marginal osteophytes and no JSN in one knee, and no signs of radiographic OA in the contra-lateral knee; this being confirmed by an expert central reader. In these participants, cartilage thickness was measured in 16 femorotibial subregions of each knee, based on sagittal DESSwe magnetic resonance images. Location-specific joint space width from fixed flexion radiographs was determined using dedicated software. Location-specific associations of osteophytes with cartilage thickness were evaluated using paired t-tests and mixed effect models. RESULTS: Of the 61 participants, 48% had only medial, 36% only lateral, and 16% bi-compartmental osteophytes. Osteophyte knees had significantly thicker cartilage than contra-lateral non-osteophyte knees in the ecMF (+71±223μm, equivalent to +5.5%, p=0.015) and ecLF (+64±195μm, +4.1%, p=0.013). No significant differences between knees were noted in other subregions, nor in joint space width. Cartilage thickness in ecMF and ecLF was significantly associated with tibial osteophytes in the same (medial or lateral) compartment (p=0.003). CONCLUSION: Knees with early radiographic OA display thicker cartilage than (contra-lateral) knees without radiographic findings of OA, specifically in the external femoral subregions of compartments with marginal osteophytes. © 2012 by the American College of Rheumatology.
Arthritis care & research. 05/2012;
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ABSTRACT: To determine whether anatomical thigh muscle cross-sectional areas (MCSAs) and strength differ between osteoarthritis (OA) knees with frequent pain compared with contra-lateral knees without pain, and to examine the correlation between MCSAs and strength in painful vs painless knees.
Forty-eight subjects (31 women; 17 men; age 45-78 years) were drawn from 4,796 Osteoarthritis Initiative (OAI) participants, in whom both knees displayed the same radiographic stage (KLG2 or 3), one with frequent pain (most days of the month within the past 12 months) and the contra-lateral one without pain. Axial MR images were used to determine MCSAs of extensors, flexors and adductors at 35% femoral length (distal to proximal) and in two adjacent 5 mm images. Maximal isometric extensor and flexor forces were used as provided from the OAI database.
Painful knees showed 5.2% lower extensor MCSAs (P=0.00003; paired t-test), and 7.8% lower maximal extensor muscle forces (P=0.003) than contra-lateral painless knees. There were no significant differences in flexor forces, or flexor and adductor MCSAs (P>0.39). Correlations between force and MCSAs were similar in painful and painless OA knees (0.44<r<0.66).
Knees with frequent pain demonstrate lower MCSAs and force of the quadriceps (but not of other thigh muscles) compared with contra-lateral knees without knee pain with the same radiographic stage. Frequent pain does not appear to affect the correlations between MCSAs and strength in OA knees. The findings suggest that quadriceps strengthening exercise may be useful in treating symptomatic knee OA.
Osteoarthritis and Cartilage 03/2012; 20(6):532-40. · 3.90 Impact Factor
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ABSTRACT: The objective of this study was to determine the interobserver reproducibility of quantitative measures of meniscus size and position, and to compare the interobserver reproducibility and agreement between a double echo steady state water excitation and an intermediately-weighted turbo spin-echo sequence. Eight knees (four healthy, four with radiographic knee osteoarthritis) from the Osteoarthritis Initiative cohort were studied. Manual segmentation of the menisci was performed by three observers and quantitative measures of meniscus size and position (i.e., extrusion) computed using image analysis software. The root mean square interobserver reproducibility error (e.g., 5.4% for medial meniscus volume with double echo steady state and 8.4% with intermediately-weighted turbo spin-echo) was found considerably smaller than the intersubject variability (average ratio ~1:3). The lowest interobserver reproducibility error for meniscus extrusion was obtained for the central five coronal slices across the tibial surface. Quantitative meniscus measures from double echo steady state and intermediately-weighted turbo spin-echo were highly correlated (r = 0.71 to 0.99 for the medial meniscus).
Magnetic Resonance in Medicine 08/2011; 67(5):1419-26. · 2.96 Impact Factor
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ABSTRACT: To explore whether quantitative, three-dimensional measurements of meniscal position and size are associated with knee pain using a within-person, between-knee study design.
We studied 53 subjects (19 men, 34 women) from the Osteoarthritis Initiative, with identical radiographic OA grades in both knees, but frequent pain in one and no pain in the other knee. The tibial plateau and menisci were analyzed using coronally reconstructed double echo steady-state sequence with water excitation (DESSwe) MRI.
The medial meniscus covered a smaller proportion of the tibial plateau (-5%) and displayed greater extrusion of the body (+15%) in painful than in painless knees (paired t-test; p < 0.05). The external margin of the lateral meniscus showed greater extrusion of the body in painful knees (+22%; p = 0.03), but no significant difference in the position of its internal margin or tibial coverage. Medial or lateral extrusion ≥3 mm was more frequent in painful (n = 23) than in painless knees (n = 12; McNemar's test; p = 0.02). No significant association was observed between meniscal size and knee pain.
These data suggest a relationship between extrusion of the meniscal body, as measured with quantitative MRI, and knee pain in subjects with knee OA. Further studies need to confirm these findings and their clinical relevance.
European Radiology 08/2011; 22(1):211-20. · 3.22 Impact Factor
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ABSTRACT: Osteoarthritis (OA) is a degenerative disease of synovial joints that is associated with symptoms (pain) and functional impairment
as well as with structural changes in various articular tissues. The articular cartilage provides the weight-bearing surface
of joints and its mechanical properties are unmet by any artificial (man-made) material. These properties ensure optimal load
transfer to the subchondral bone and an almost frictionless surface in healthy joints. Cartilage volume consists of 80–90%
water, which is undergoing hydrostatic pressurization during load transmission [1]. This hydrostatic pressurization mechanism
prevents focal load peaks at the subchondral bone interface, it protects the vulnerable cartilage matrix from damage, and
it provides the cartilage with a friction coefficient that is 10 times lower than that of ice on ice. It is for this reason
that articular cartilage is integral to appropriate joint function and that its loss is associated with functional impairment.
Cartilage also is the tissue that has generated most interest in context of quantitative measurement in OA with MRI.
KeywordsOsteoarthritis-MR imaging-Cartilage-Knee-Progression-Morphology-Quantitative
06/2011: pages 127-144;
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ABSTRACT: To investigate whether rates of cartilage loss differ in knees with frequent baseline pain versus those without pain, after adjustment for radiographic osteoarthritis (OA) stage.
One knee in each of 718 Osteoarthritis Initiative participants was examined: 310 with calculated Kellgren/Lawrence (K/L) grade 2, 299 with calculated K/L grade 3, and 109 with calculated K/L grade 4. Twelve-month change in (subregional) cartilage thickness was assessed by magnetic resonance imaging. Change in cartilage thickness in the central subregion of the weight-bearing medial femoral condyle and ordered value 1 (OV1) were selected as primary end points. Frequent knee symptoms were defined as pain, aching, or stiffness on most days of at least 1 month during the previous year.
The mean 12-month rate of change in cartilage thickness in the central subregion of the medial femoral condyle was -12 μm (standardized response mean [SRM] -0.15) in knees without pain (n = 146), -27 μm (SRM -0.25) in those with infrequent pain (n = 255), and -54 μm (SRM -0.32) in those with frequent pain (n = 317). Rates differed significantly between frequently painful knees and pain-free knees after adjustment for age, sex, body mass index, and calculated K/L grade (P = 0.011, R(2) = 2.6%, partial R(2) for frequent pain = 1.4%). Similar results were found in stratified samples of calculated K/L grade 2/calculated K/L grade 3 knees, and in analyses restricted to knees with consistent pain frequency between baseline and followup. OV1 results showed similar trends but were not significant.
Knees with frequent pain display greater rates of medial cartilage loss longitudinally than knees without pain, with or without adjustment or stratification for radiographic disease stage. Enrollment of participants with frequent knee pain in clinical trials can increase the observed rate of structural progression (i.e., cartilage loss) and sensitivity to change.
Arthritis & Rheumatism 04/2011; 63(8):2257-67. · 7.87 Impact Factor
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ABSTRACT: To explore and to compare the magnitude and spatial pattern of in vivo femorotibial cartilage deformation in healthy and in osteoarthritic (OA) knees.
One knee each in 30 women (age: 55 ± 6 years; BMI: 28 ± 2.4 kg/m(2); 11 healthy and 19 with radiographic femorotibial OA) was examined at 3Tesla using a coronal fat-suppressed gradient echo SPGR sequence. Regional and subregional femorotibial cartilage thickness was determined under unloaded and loaded conditions, with 50% body weight being applied to the knee in 20° knee flexion during imaging.
Cartilage became significantly (p < 0.05) thinner during loading in the medial tibia (-2.7%), the weight-bearing medial femur (-4.1%) and in the lateral tibia (-1.8%), but not in the lateral femur (+0.1%). The magnitude of deformation in the medial tibia and femur tended to be greater in osteoarthritic knees than in healthy knees. The subregional pattern of cartilage deformation was similar for the different stages of radiographic OA.
Osteoarthritic cartilage tended to display greater deformation upon loading than healthy cartilage, suggesting that knee OA affects the mechanical properties of cartilage. The pattern of in vivo deformation indicated that cartilage loss in OA progression is mechanically driven.
European Radiology 03/2011; 21(6):1127-35. · 3.22 Impact Factor
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W Wirth,
R Buck,
M Nevitt,
M P H Le Graverand,
O Benichou,
D Dreher,
R Y Davies,
J H Lee,
K Picha,
A Gimona,
S Maschek,
M Hudelmaier,
F Eckstein
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ABSTRACT: The sensitivity to change of quantitative analysis of cartilage in knee osteoarthritis using magnetic resonance imaging (MRI) is compromised by the spatial heterogeneity of cartilage loss. We explore whether extended (medial-lateral) "ordered values" (OVs) are superior to conventional approaches of analyzing subregional cartilage thickness loss and to radiography, in differentiating rates of progression in knees with and without joint space narrowing (JSN).
607 Osteoarthritis Initiative (OAI) participants (308 without and 299 with baseline JSN at baseline) were studied over 12 months. Subregional femorotibial cartilage loss was determined in all knees, and changes in minimum joint space width (mJSW) in a subset of 290 knees. Subregional thickness changes in medial and lateral tibial and femoral cartilages were sorted in ascending order (OV1-16). A Wilcoxon rank-sum test was used to compare rates of change in knees with and without JSN.
JSN-knees displayed greater cartilage loss than those without JSN, with minimal P-values of 0.008 for femorotibial subregions, 3.3×10(-4) for medial OV1, and 5.4×10(-7) for extended (medial and lateral) OV1. mJSW measurements (n=290) did not discriminate between longitudinal rates of change in JSN vs no-JSN knees (P=0.386), whereas medial OV1 (P=5.1×10(-4)) and extended OV1 did (P=2.1×10(-5)).
Extended OVs showed higher sensitivity to detecting differences in longitudinal rates of cartilage loss in knees with and without baseline JSN than anatomical (sub)regions and radiography. The OV technique also circumvents challenges of selecting particular regions "a priori" in clinical trials and may thus provide a powerful tool in studying risk factors or treatment efficacy in osteoarthritis.
Osteoarthritis and Cartilage 02/2011; 19(6):689-99. · 3.90 Impact Factor
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ABSTRACT: 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.
Arthritis. 01/2011; 2011:475684.
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ABSTRACT: Meniscus extrusion or hypertrophy may occur in knee osteoarthritis (OA). However, currently no data are available on the position and size of the meniscus in asymptomatic men and women with normal meniscus integrity.
Three-dimensional coronal DESSwe MRIs were used to segment and quantitatively measure the size and position of the medial and lateral menisci, and their correlation with sex, height, weight, and tibial plateau area. 102 knees (40 male and 62 female) were drawn from the Osteoarthritis Initiative "non-exposed" reference cohort, including subjects without symptoms, radiographic signs, or risk factors for knee OA. Knees with MRI signs of meniscus lesions were excluded.
The tibial plateau area was significantly larger (p < 0.001) in male knees than in female ones (+23% medially; +28% laterally), as was total meniscus surface area (p < 0.001, +20% medially; +26% laterally). Ipsi-compartimental tibial plateau area was more strongly correlated with total meniscus surface area in men (r = .72 medially; r = .62 laterally) and women (r = .67; r = .75) than contra-compartimental or total tibial plateau area, body height or weight. The ratio of meniscus versus tibial plateau area was similar between men and women (p = 0.22 medially; p = 0.72 laterally). Tibial coverage by the meniscus was similar between men and women (50% medially; 58% laterally), but "physiological" medial meniscal extrusion was greater in women (1.83 ± 1.06mm) than in men (1.24mm ± 1.18mm; p = 0.011).
These data suggest that meniscus surface area strongly scales with (ipsilateral) tibial plateau area across both sexes, and that tibial coverage by the meniscus is similar between men and women.
BMC Musculoskeletal Disorders 01/2011; 12:248. · 1.58 Impact Factor
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ABSTRACT: Varus-valgus alignment has been linked to subsequent progression of osteoarthritis (OA) within the mechanically stressed (medial for varus, lateral for valgus) tibiofemoral compartment. Cartilage data from the off-loaded compartment are sparse. The purpose of this study was to examine our hypotheses that neutral and valgus (versus varus) knees each have reduced odds of cartilage loss in the medial subregions and that neutral and varus (versus valgus) knees each have reduced odds of cartilage loss in the lateral subregions.
Patients with knee OA underwent knee magnetic resonance imaging at baseline and 2 years. The mean cartilage thickness was quantified within 5 tibial and 3 femoral subregions. We used logistic regression with generalized estimating equations to analyze the relationship between baseline alignment and subregional cartilage loss at 2 years, adjusting for age, sex, body mass index, and disease severity.
A reduced risk of cartilage loss in the medial subregions was associated with neutral (versus varus) alignment (external tibial, central femoral, external femoral) and with valgus (versus varus) alignment (central tibial, external tibial, central femoral, external femoral). A reduced risk of cartilage loss in the lateral subregions was associated with neutral (versus valgus) alignment (central tibial, internal tibial, posterior tibial) and with varus (versus valgus) alignment (central tibial, external tibial, posterior tibial, external femoral).
Neutral and valgus alignment were each associated with a reduction in the risk of subsequent cartilage loss in certain medial subregions and neutral and varus alignment with a reduction in the risk of cartilage loss in certain lateral subregions. These results support load redistribution as an in vivo mechanism of the long-term alignment effects on cartilage loss in knee OA.
Arthritis & Rheumatism 01/2011; 63(4):1002-9. · 7.87 Impact Factor
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ABSTRACT: Meniscal tears have been linked to knee osteoarthritis progression, presumably by impaired load attenuation. How meniscal tears affect osteoarthritis is unclear; subregional examination may help to elucidate whether the impact is local. This study examined the association between a tear within a specific meniscal segment and subsequent 2-year cartilage loss in subregions that the torn segment overlies.
Participants with knee osteoarthritis underwent bilateral knee MRI at baseline and 2 years. Mean cartilage thickness within each subregion was quantified. Logistic regression with generalised estimating equations were used to analyse the relationship between baseline meniscal tear in each segment and baseline to 2-year cartilage loss in each subregion, adjusting for age, gender, body mass index, tear in the other two segments and extrusion.
261 knees were studied in 159 individuals. Medial meniscal body tear was associated with cartilage loss in external subregions and in central and anterior tibial subregions, and posterior horn tear specifically with posterior tibial subregion loss; these relationships were independent of tears in the other segments and persisted in tibial subregions after adjustment for extrusion. Lateral meniscal body and posterior horn tear were also associated with cartilage loss in underlying subregions but not after adjustment for extrusion. Cartilage loss in the internal subregions, not covered by the menisci, was not associated with meniscal tear in any segment.
These results suggest that the detrimental effect of meniscal tears is not spatially uniform across the tibial and femoral cartilage surfaces and that some of the effect is experienced locally.
Annals of the rheumatic diseases 01/2011; 70(1):74-9. · 8.11 Impact Factor
