Lower hand grip in rheumatoid arthritis patients is associated with low finite element analysis using high resolution peripheral quantitative computed tomography scan of the 2nd metacarpophalangeal joint.

Aim: To evaluate hand function by hand grip test in rheumatoid arthritis (RA) patients, and its association with bone erosions and the estimated bone strength (finite element - FE analysis) through the analysis of the 2nd metacarpal head of the dominant hand using high resolution peripheral quantitative computed tomography (HR-pQCT).

Method: Eighty-two female RA patients between 18-50 years old were selected. Demographic data, Health Questionnaire Assessment Disability Index (HAQ), Disease Activity Score of 28 joints (DAS)-28, simplified disease activity index (SDAI) and the hand grip test were set. The HR-pQCT scans of 2nd metacarpophalangeal joints of the dominant hand of all patients were performed according to SPECTRA group protocols. The images were used to assess bone erosions and FE analysis. The hand grip test was categorized in 2 groups and separately compared (< 18 vs ≥18 kgf). A logistic regression was performed using hand grip test <18 kgf as a dependent variable.

Results: A significant difference was found between the 2 groups regarding HAQ, inflammatory markers (erythrocyte sedimentation rate, C-reactive protein), DAS-28, SDAI, total volume of erosion and bone strength parameter (FE analysis - Failure Load [F.Load]). The logistic regression analysis showed that the risk factors associated with hand grip test <18 kgf were higher SDAI (odds ratio [OR] 0.912; 95% CI 0.837-0.993) and lower values of bone strength parameter (F.Load) (OR 1.007; 95% CI 1.002-1.012).

Conclusion: Lower values of hand grip test were associated with higher disease activity score-SDAI and lower bone strength of 2nd metacarpal bone head of the dominant hand evaluated here through a FE analysis using HR-pQCT scan.