Background: Impaired hand grip function is common and occurs early in the course of disease in patients with rheumatoid arthritis (RA) and hand osteoarthritis (HOA), affecting daily life activities and quality of life.

Objectives: To evaluate muscle force and muscle activity in forearm flexors and extensors during daily activities and clinically well-known hand exercises in women with RA and HOA compared with healthy controls

Methods: The RA group was consecutively included from a specialist clinic and had a disease duration of at least one year.  Women with HOA were allocated from out-patients primary health care clinics in the same area and clinically diagnosed with symptomatic HOA. The age matched control group had no history of hand/arm injuries, inflammatory or muscle disease. Full active finger extension ability was required for all subjects. Hand force (Newton) was measured with EX-it (extension) and Grippit (flexion), both validated instruments. Muscle activity was measured in m. extensor digitorum communis (EDC) and m. flexor carpi radialis (FCR) with surface EMG (S-EMG) on the dominant hand while performing four daily activities (ADL) and four hand exercises and described as percent of maximal voluntary isometric contraction (% MVIC) based on data from EX-it and Grippit. Pain was measured with Visual Analogue Scale (VAS) 0-10 (best to worst). Differences between groups were analyzed and controlled for age.

Results: Fifty-six women were included; 20 with RA (age mean (SD) 59.2 (10.7) years, VAS pain 2.2 (1.6)), 16 with HOA (age 67.5 (9.3) years, VAS pain 4.1 (1.9)) and 20 healthy controls (age 56.0 (9.7) years). Women with RA and HOA showed decreased extension and flexion force compared with healthy women (p<0.03).There was a tendency towards higher % MVIC in all tests for women with RA or HOA compared with healthy women, with a statistically significant difference between HOA and healthy women for EDC (p<0.05).

ADL activities “writing with a pen”, and “cutting with scissors” showed the highest % MVIC in both EDC and FCR in all groups. The exercises “isolated opposition”, and “rolling the dough with flat hands”, had high % MVIC in EDC, while “squeezing the dough” and “isolated opposition” had high % MVIC in FCR.

Conclusions: Women with RA and HOA tend to use a higher % MVIC than healthy women in many daily activities and in hand exercises. Strengthening exercises should include both extensor and flexor specific training.

Disclosure of Interest: None Declared