Objective: The objective of this study was to determine the prevalence and distribution of bone erosions detectable by US in patients with early RA (ERA) in comparison with long-standing RA (LSRA), other erosive diseases and healthy controls.
Methods: Thirty patients with ERA and 80 patients with LSRA were consecutively recruited. Thirty patients with PsA, 15 with primary OA, 10 with gout and 20 healthy subjects were included as controls. Bone erosions were investigated at the following anatomical sites: the second and fifth metacarpal heads, the ulnar head and the first and fifth metatarsal heads, bilaterally. Dorsal, volar and lateral aspects were explored on longitudinal and transverse views.
Results: At least one US bone erosion was found in 20 (66.7%) of 30 patients with ERA and in 10 (33%) of them it was found on the fifth metatarsal head. Bone erosions were most frequently found on the lateral quadrants of all scanned anatomical sites. If the second and fifth metacarpal heads and the fifth metatarsal head were scanned, an erosive disease could be found in 60% of ERA patients. The first metatarsal head was most frequently involved in the disease control group.
Conclusion: This study found a high percentage of ERA patients with US bone erosions, with the fifth metatarsal head and the lateral aspects the most frequently involved site and quadrants. US scanning for bone erosions on a few target joints was found feasible and provided information not obtainable with clinical examination.