Low prevalence of knee chondrocalcinosis and its catabolic association with serum matrix metalloproteinase 3: A rural Japanese population study.

AIM: This study aimed to elucidate the prevalence of radiographic knee chondrocalcinosis (CC) and to clarify whether CC is correlated with self-reported knee symptoms and a serum catabolic biomarker.

METHODS

A total of 1278 volunteers participated. Plain radiographs of both knees were obtained. Identification of a linear calcification in the knee joint space was defined as CC. Patients with a Kellgren-Lawrence grade of 2 or more were considered to have knee osteoarthritis (OA). Symptoms were evaluated using the Knee injury and Osteoarthritis Outcome Score (KOOS) Pain scale, and serum matrix metalloproteinase-3 (MMP-3) concentration was determined. Multiple regression analysis was conducted to determine whether CC was correlated with OA, the KOOS Pain scale and MMP-3 concentration.

RESULTS

Twenty-eight subjects were found to have CC (2.2%), and 389 had OA (30.4%). CC was correlated with OA (odds ratio: 5.797; P = 0.006). Additionally, CC was correlated with MMP-3 concentration (B = 11.415, β = 0.059, P = 0.014), but not with KOOS Pain scale.

CONCLUSIONS

The prevalence of CC was low in the Japanese population evaluated in this study. While CC was not correlated with self-reported knee symptoms, it was positively correlated with serum MMP-3 concentration.