Anatomical location of erosions at the metatarsophalangeal joints in patients with rheumatoid arthritis.
OBJECTIVE
The aim of this study was to identify the anatomical location of erosions at the MTP joints in patients with RA using high-resolution 3T MRI.


METHODS
In 24 patients with RA, the more symptomatic forefoot was imaged using 3T MRI. T1-weighted, intermediate-weighted and T2-weighted fat-suppressed sequences were acquired through the MTP joints, together with three-dimensional volumetric interpolated breath-hold examination (3D VIBE) and T1-weighted fat-suppressed post-gadolinium contrast sequences. Images were scored for bone erosion in the distal and proximal part of the MTP joints using the RA MRI scoring (RAMRIS) system. The base of the proximal phalanx and the head of the metatarsal were divided into quadrants to determine the location of erosions (octants) in the dorsal-medial, dorsal-lateral, plantar-medial and plantar-lateral regions.


RESULTS
Seventeen females and seven males with a mean age of 55.5 years and disease duration of 10.6 years (range 0.6-36) were included. Eighteen patients were RF positive, the mean 44-joint DAS for CRP and ESR (DAS44CRP and DAS44ESR) were 2.5 (s.d. 0.8) and 2.6 (s.d. 0.9), respectively. In this cohort of patients with RA, irrespective of MTP joint location, octants located in the proximal part (metatarsal) of the joint and the plantar aspect of the joint were more eroded.


CONCLUSIONS
This is the first study to report the anatomical location of erosions at the MTP joints in patients with RA. We noted that erosions were more commonly seen on the plantar aspect of the metatarsal head in RA, supporting the hypothesis of a relationship between biomechanical demands and bone changes in the forefoot.
Leeds Institute of Rheumatic and Musculoskeletal Medicine, University of Leeds, Chapel Allerton Hospital, Chapeltown Road, Leeds LS7 4SA, UK. h.siddle@leeds.ac.uk.
Heidi J
HJ
Siddle
Elizabeth M A
EM
Hensor
Richard J
RJ
Hodgson
Andrew J
AJ
Grainger
Anthony C
AC
Redmond
Richard J
RJ
Wakefield
Philip S
PS
Helliwell
D000368:Aged; D001172:Arthritis, Rheumatoid / Q000473:pathology* / Q000503:physiopathology; D001696:Biomechanical Phenomena / Q000502:physiology; D015331:Cohort Studies; D005260:Female; D005545:Forefoot, Human / Q000473:pathology / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008683:Metatarsophalangeal Joint / Q000473:pathology* / Q000503:physiopathology; D008875:Middle Aged; D012720:Severity of Illness Index
RAMRIS; erosion; magnetic resonance imaging; metatarsophalangeal joint; rheumatoid arthritis