Article

Frequency and Spatial Distribution of Cartilage Thickness Change in Knee Osteoarthritis and its Relation to Clinical and Radiographic Covariates - Data from the Osteoarthritis Initiative.

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Osteoarthritis and Cartilage (Impact Factor: 4.17). 10/2012; 21(1). DOI: 10.1016/j.joca.2012.10.010
Source: PubMed

ABSTRACT

Objective:
Estimate the frequency and spatial location of rapid femorotibial cartilage thinning or thickening in knees with, or at risk of, osteoarthritis (OA) 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 (JSN). 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-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 JSN and/or frequent knee pain are present.

  • Source
    • "The severity of OA is usually graded through different radiographic and/or histomorphometric scores. The Kellgren and Lawrence system provides a score of severity from zero to four: Grade 0, no radiographic features of OA are present; Grade 1, doubtful joint space narrowing (JSN) and possible osteophytic lipping; Grade 2, definite osteophytes and possible JSN on anteroposterior weight-bearing radiograph; Grade 3, multiple osteophytes, definite JSN, sclerosis, possible bony deformity; Grade 4, large osteophytes, marked JSN, severe sclerosis and definite bony deformity[22]. The Kraus' modified Mankin score provides grades from zero to four: Grade 0, normal cartilage; Grade 1, minimal articular damage; Grade 2, articular cartilage damage affecting up to 30% of the articular surface; Grade 3, loss of up to 50% of the articular cartilage; Grade 4, severe loss of cartilage affecting more than 50% of the articular surface[23,24]. "

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