Ultrasound Measurement of Femoral Cartilage Thickness in Patients with Familial Mediterranean Fever and its Relation to Amyloidosis and Other Disease Characteristics.

Objectives: This study aimed to determine femoral cartilage thickness (FCT) in patients with familial Mediterranean fever (FMF) and healthy individuals and to assess the relationship of FCT with the development of amyloidosis and clinical features.

Methods: Patients diagnosed with FMF according to the Tel-Hashomer criteria and healthy controls were included in the study. FCT of both knees was measured with a 7-12 MHz linear probe in maximum knee flexion. Three midpoint measurements were obtained from each knee: Lateral femoral condyle (LFC), intercondylar area (ICA), and medial femoral condyle (MFC). The patients' clinic characteristics include disease duration, medications, comorbid conditions, amyloidosis, chronic renal failure (CRF), FMF gene mutation, arthritis, sacroiliitis, PRAS score, and Physical Activity Questionnaire Short Form score were recorded.

Results: A total of 46 patients with FMF (36 women) and 20 age-sex-body mass index-matched controls (14 women) were enrolled in this study. The patients and controls' mean age were 37±12.9 and 37.5±8.6 years, respectively. Amyloidosis occurred in 7 patients (15.2%), CRF in 3 (6.5%), and knee arthritis in 8 (17%). Disease activity was mild in 55.8%, moderate in 20.9%, and severe in 23.23% of the patients. The mean FCT in millimeter values in the FMF and control groups was as follows: On the right side, LFC 1.9±0.5 and 2±0.52, ICA 2.2±0.77 and 2.25±0.97, and MFC 2±0.47 and 2.25±0.72; on the left side, LFC 1.9±0.4 and 2.05±0.55, ICA 2.25±0.87 and 2.25±0.87, and MFC 1.85±0.5 and 2.25±0.6. Patients with FMF had decreased cartilage thickness at the lateral condyle of both knees (p<0.05) and medial condyle of the left knee (p<0.05) compared with controls. FCT measurements were similar in patients with or without arthritis, amyloidosis, and CRF (p>0.05). FCT scores were not different among the disease activity groups (p>0.05).

Conclusion: These findings suggest that patients with FMF have decreased FCT compared with controls, and there is no significant relationship between the FCT and amyloidosis and disease activity.