275 CLINICAL ASPECTS OF EROSIVE HAND OSTEOARTHRITIS

Abstract

Purpose: Erosive hand osteoarthritis (HOA) is considered a subset of HOA. The difference between erosive and non-erosive HOA with respect to pain and functioning is largely unknown and therefore subject of this study. Methods: Patients with familial OA participating in the GARP (Genetics ARthrosis and Progression) study, were eligible for the present analysis if they had HOA defined by the ACR criteria for clinical HOA or the presence of structural abnormalities (multiple bony swellings/radiological OA) in the hands. Erosive HOA was defined as the presence of erosive radiographic features according to the Verbruggen-Veys anatomical phase score in at least 2 interphalangeal joints. Self-reported hand pain and function were assessed with the Australian/Canadian Osteoarthritis Hand Index (AUSCAN LK 3.0). A standard diagram of the hand joints was used to identify the number painful joints. During physical examination pain intensity upon lateral pressure in all hand joints was graded 0-3 and the number of bony swellings was recorded. Performance was evaluated with grip strength, pinch grip, fingerpalm distance during finger flexion and the HAMIS (Hand Mobility in Scleroderma), which assesses all movements included in the range of motion of the hand. Higher scores on the HAMIS reflect worse hand mobility. Measures of pain and functioning were compared between patients with erosive and non-erosive HOA using t-test and Mann-Whitney U test for normally and not-normally distributed variables, respectively. Performance measures were related to AUSCAN using linear regression with adjustment for age, sex, and body mass index. Results: Erosive HOA was present in 42 (18%) of 236 HOA patients (83% women, mean age 65 yrs). Demographics characteristics did not differ between the groups. Clinical measures are shown in the table. Patients with erosive HOA experienced more pain and reported more functional limitations than patients with non-erosive HOA. Grip strength and pinch grip did not differ between the groups. The HAMIS was significantly worse in patients with erosive HOA, which was found for finger mobility, but not for thumb mobility. Finger-palm distance was higher in patients with erosive HOA. HAMIS and finger-palm distance were related to AUSCAN pain and function in both groups, whereas grip strength and pinch grip were related to the AUSCAN only in non-erosive HOA.