Frequency and Spatial Distribution of Cartilage Thickness Change in Knee Osteoarthritis and its Relation to Clinical and Radiographic Covariates - Data from the Osteoarthritis Initiative.
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.
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ABSTRACT: Modern image analysis enables the accurate quantification of knee osteoarthritis (OA) bone using MRI. We hypothesised that three-dimensional changes in bone would be characteristic of OA and provide a responsive measure of progression. 1312 participants with radiographic knee OA, and 885 non-OA controls with MRIs at baseline, 1, 2 and 4 years were selected from the NIH Osteoarthritis Initiative. Automated segmentation of all knee bones and calculation of bone area was performed using active appearance models. In a subset of 352 participants, responsiveness of bone area change was compared with change in radiographic joint space width (JSW) and MRI cartilage thickness over a 2-year period. All OA knee compartments showed increased bone area over time compared with non-OA participants: for example, the 4-year percentage change from baseline in medial femur area for OA (95% CI) was 1.87(0.13), non-OA 0.43 (0.07); p<0.0001. Bone area change was more responsive than cartilage thickness or JSW; 2-year SRM for bone area in the medial femur was 0.83, for the most responsive cartilage thickness measure central medial femorotibial composite (cMFTC): 0.38, JSW: 0.35. Almost half of all knees had change greater than smallest detectable difference at 2 years. Body mass index, gender and alignment had only a small effect on the rate of change of bone area. Changes in bone area discriminated people with OA from controls and was more responsive than the current and impending standards for assessing OA progression. The shape change in OA bone provides a new window on OA pathogenesis and a focus for clinical trials.Annals of the rheumatic diseases 12/2013; 74(3). DOI:10.1136/annrheumdis-2013-204052 · 9.27 Impact Factor
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ABSTRACT: The Osteoarthritis Initiative (OAI) is a multicentre, prospective, observational, cohort study of knee osteoarthritis (OA) that began recruitment in 2004. The OAI provides public access to clinical and image data, enabling researchers to examine risk factors/predictors and the natural history of knee OA incidence and progression, and the qualification of imaging and other biomarkers. In this narrative review, we report imaging findings and lessons learned 10 years after enrolment has started. A literature search for full text articles published from the OAI was performed up to 31 December 2013 using Pubmed and the OAI web page.We summarise the rationale, design and imaging protocol of the OAI, and the history of OAI publications. We review studies from early partial, and later full OAI public data releases. The latter are structured by imaging method and tissue, reviewing radiography and then MRI findings on cartilage morphology, cartilage lesions and composition (T2), bone, meniscus, muscle and adipose tissue. Finally, analyses directly comparing findings from MRI and radiography are summarised. Ten years after the first participants were enrolled and first papers published, the OAI has become an invaluable resource to the OA research community. It has fuelled novel methodological approaches of analysing images, and has provided a wealth of information on OA pathophysiology. Continued collection and public release of long-term observations will help imaging measures to gain scientific and regulatory acceptance as 'prognostic' or 'efficacy of intervention' biomarkers, potentially enabling shorter and more efficient clinical trials that can test structure-modifying therapeutic interventions (NCT00080171).Annals of the rheumatic diseases 04/2014; 73(7). DOI:10.1136/annrheumdis-2014-205310 · 9.27 Impact Factor
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ABSTRACT: Objective To test the hypothesis that cartilage displays significant longitudinal thickening in the external subregions of the central medial femur (ecMF) and lateral femur (ecLF) in knees with early radiographic osteoarthritis (ROA) compared with contralateral knees without ROA, and to explore differences in change in other subregions and in radiographic joint space width (JSW). Methods Fifty participants (50% women, mean SD age 61.1 9.7 years, and mean +/- SD body mass index 27.7 +/- 4.7 kg/m(2)) were identified from the Osteoarthritis Initiative cohort with definite femorotibial osteophytes but no joint space narrowing (JSN) in 1 knee (early ROA), and no osteophytes or JSN in the contralateral knee (non-ROA). A longitudinal within-person, between-knee comparison was performed using measures of subregional cartilage thickness based on analyses of sagittal double-echo steady-state magnetic resonance images obtained at baseline and 1 year. Medial JSW was evaluated from fixed-flexion radiographs. ResultsThe change between baseline and 1 year was -6 +/- 94 m in ecMF and +18 +/- 91 m in ecLF in early ROA (P = 0.78) versus -1 +/- 68 m and +4 +/- 76 m in non-ROA knees (P = 0.38). The variability of cartilage thickness change tended to be greater in early ROA than in non-ROA knees. Greater cartilage thickness loss in the lateral tibia and a greater reduction in minimum medial JSW were observed in early ROA versus non-ROA knees. Conclusion There was no direct evidence of longitudinal cartilage thickening in external subregions of the central femur in knees with early ROA compared with contralateral non-ROA knees. The observed greater variability in longitudinal thickness change in early ROA knees (but not in non-ROA knees) might be due to cartilage thickening and thinning occurring simultaneously in these knees.04/2014; 66(4). DOI:10.1002/acr.22172