Chondrocalcinosis is common in the absence of knee involvement

ABSTRACT: INTRODUCTION: We aimed to describe the distribution of radiographic chondrocalcinosis (CC) and to examine if metacarpophalangeal joints (MCPJ) calcification and CC at other joints occurs in the absence of knee involvement. METHODS: This was a cross sectional study embedded in the Genetics of Osteoarthritis and Lifestyle study (GOAL). All participants (n=3,170) had radiographs of the knees, hands, and pelvis. These were scored for radiographic changes of osteoarthritis (OA), for CC at knees, hips, symphysis pubis, wrists, and for MCPJ calcification. The prevalence of MCPJ calcification and CC overall, at each joint, and in the presence or absence of knee involvement was calculated. RESULTS: The knee was the commonest site of CC, followed by wrists, hips and symphysis pubis. CC was more likely to be bilateral at knees and wrists but unilateral at hips. MCPJ calcification was usually bilateral, and less common than CC at knees, hips, wrists, and symphysis pubis. Unlike previously reported, CC commonly occurred without any knee involvement. 44.4% of wrist CC, 45.9% of hip CC, 45.5% of symphysis pubis CC, and 31.3% of MCPJ calcification occurred in patients without knee CC. Those with meniscal or hyaline articular cartilage CC had comparable age (P=0.21), and neither preferentially associated with fibrocartilage CC at distant joints. CONCLUSIONS: CC visualised on a plain radiograph commonly occurs at other joints in the absence of radiographic knee CC. Therefore, knee radiographs alone are an insufficient screening test for CC. This has significant implications for clinical practice, for epidemiological and genetic studies of CC, and for the definition of OA patients with co-existent crystal deposition.