Bigger Osteophyte Size Ups Severe Cartilage Damage Risk
Low prevalence of atrophic and hypertrophic phenotypes in MRI-diagnosed knee osteoarthritis
TUESDAY, Sept. 27 (HealthDay News) -- For patients with magnetic resonance imaging (MRI)-diagnosed tibiofemoral osteoarthritis, the likelihood of severe cartilage damage increases with increasing osteophyte size, and only a small proportion of knees exhibit atrophic and hypertrophic phenotypes, according to a study published online Sept. 14 in Arthritis & Rheumatism.
Frank W. Roemer, M.D., from the Boston University Medical Center, and colleagues investigated the association between osteophytes and cartilage damage on semiquantitative MRI assessment, and estimated the prevalence of atrophic and hypertrophic phenotypes of tibiofemoral knee osteoarthritis in 1,597 knees from 1,248 subjects. Study participants were examined using a 1.5 tesla MRI system using triplanar intermediate-weighted fat suppressed sequences. Cartilage and osteophytes were assessed by the Whole-Organ Magnetic Resonance Imaging Score. The odds ratios of severe cartilage damage were estimated according to osteophyte size. In another analysis, including all 10 tibiofemoral regions, knees with absent or tiny osteophytes (≤2 on a 0 to 7 scale), but severe cartilage damage (atrophic), and knees with large osteophytes (≥5 on a 0 to 7 scale), but with no substantial cartilage damage (hypertrophic), were assessed in relation to radiographic osteoarthritis status.
The investigators found that 80.6 percent of the knees with large osteophytes had severe cartilage damage. There was a marked increase in the risk of severe cartilage damage with increase in osteophyte size. Atrophic and hypertrophic phenotype were identified in 1.3 and 0.2 percent of the knees, respectively.
"A marked increase in odds of severe cartilage damage was observed with increasing osteophyte size. Only a small minority of knees exhibited the so-called atrophic and hypertrophic phenotypes," the authors write.
Two authors disclosed financial relationships with the biopharmaceutical, health care, and medical device industries.