Evaluation of the thicknesses of cartilage and enthesis in familial Mediterranean fever and enthesitis-related arthritis

OBJECTIVE: Subclinical inflammation is still a controversial issue in inflammatory diseases. There is no reliable, easy, and cheap inflammation marker in daily clinical practices currently. This study aims to predict clinical remission using cartilage and tendon thicknesses. METHODS: Eleven patients with Familial Mediterranean Fever (FMF) who had musculoskeletal involvement before and 11 patients with Enthesitis-Related Arthritis (ERA) were included in this study. They were on remission with clinical and laboratory evaluations for at least three months. Demographic and clinical features of the subjects, including age, sex, body mass index, disease duration, age at onset, medical treatment, and laboratory evaluations, were all noted. Healthy children of the same age were included as the control group. The thicknesses of the bilateral knee, second metacarpophalangeal and ankle joints cartilages, quadriceps, superior and inferior patellar, and the Achilles tendons were measured with a linear probe. A total of 198 joint and 264 tendon thicknesses were measured. RESULTS: The thicknesses of metacarpophalangeal, knee, and ankle cartilages were higher in the FMF group than in the others. In the FMF group, the quadriceps tendon thickness was higher than in the ERA group, and the superior patellar tendon thickness was higher than in the control group (p<0.05). CONCLUSION: According to our preliminary findings, an increased thickness of the cartilage and tendon in FMF patients may be an indicator of subclinical inflammation. Increased thickness of the enthesis in FMF patients may also indicate that enthesitis-related arthritis will also develop in the future.