Arthropathy and Tendinopathy in Patients with Tophaceous and Non-tophaceous Gout: A Case-controlled Ultrasonographic Study

Abstract

Objective: To determine the characteristics of tendon and joint involvement in patients with tophaceous and non-tophaceous gout on ultrasonography (US). Method: We performed a prospective, observational, case-controlled study using US to evaluate the knee, ankle, 1st and 2nd metatarsal-phalangeal (MTP) joints, and the tendons and entheses of the lower limbs. Differences were analyzed by Fisher’s exact or Mann-Whitney U-tests. Results: Twenty-four patients with tophaceous gout and 36 subjects with nontophaceous gout were recruited. Double contour signs (DCS) of the femoral condyles were significantly more prevalent in the tophaceous gout group compared to the non-tophaceous group (50% vs. 15.3%; p=0.001). The 1st and 2nd MTP joints of patients with tophaceous gout had significantly more DCS, periarticular tophi, and bone erosions than patients with non-tophaceous gout (p≤0.002). Intratendinous tophi in the Achilles tendons (43.8% vs. 6.9%), proximal/distal patella tendons (29.2%/41.7% vs. 1.4%/8.3%), tibialis anterior/posterior tendons (14.6%/39.6% vs. 0/1.4%), and peroneus longus and brevis tendons (29.2% vs. 0) were significantly more frequent in patients with tophaceous gout than patients with non-tophaceous gout (p≤0.002). Enthesopathies were commonly observed; specifically 7.5% of proximal patella tendons, 20% of distal patella tendons, and 13.3% of Achilles tendons presented with enthesopathies. No statistical differences existed between groups. Conclusion: Patients with tophaceous gout had significantly more prevalent intra- and extra-articular pathology on US, suggesting a larger quantity of monosodium urate depositions, than patients with non-tophaceous gout. We thus recommend a more aggressive and longer duration of urate-lowering therapy in patients with tophaceous gout.