Neogi T et al. (2006) Lack of association between chondrocalcinosis and increased risk of cartilage loss in knees with osteoarthritis: results of two prospective longitudinal magnetic resonance imaging studies. Arthritis Rheum 54: 1822–1828

Chondrocalcinosis (the deposition of calcium pyrophosphate dihydrate crystals in hyaline articular and/or meniscal fibrocartilage) is not associated with cartilage loss in osteoarthritic knees, say Neogi et al. Their finding is not new, but is important, as concerns about the sensitivity of radiographic detection of cartilage loss brought the findings of earlier, similar studies into question.

Neogi and colleagues used longitudinal MRI assessments to study 265 knees in 265 patients (mean age 67 years; 88% white; 42% female) with symptomatic osteoarthritis from the Boston Osteoarthritis Knee Study. Findings were then compared with those from a second cohort of 230 individuals (mean age 74 years; 69% female; 49% white) from the Health, Aging, and Body Composition Study, who had radiographic evidence of osteoarthritis.

Chondrocalcinosis was present in 23 of the 265 knees included in the Boston study, and was associated with a markedly lower risk of cartilage loss (two-fifths of that in knees without chondrocalcinosis). This reduced risk remained when just knees with damaged menisci were analyzed. A similar trend, perhaps suggesting a protective role of chondrocalcinosis, was observed in the 373 knees in the Health, Aging, and Body Composition study.

The authors suggest that chondrocalcinosis might indicate the presence of hypertrophic chondrocytes, which are associated with dysregulated matrix synthesis—a putative repair mechanism in injured joints. Further investigation of the effect of incident chondrocalcinosis on cartilage loss is required, as too few cases occurred in this study.