Structural damage in rheumatoid arthritis: comparison between dominant and non-dominant hand

The authors analyzed the effect of mechanical stress on the progression of rheumatoid arthritis (RA) in the hands.  

In RA, high levels of immune system proteins are generated. This causes inflammation, leading to chronic pain and structural damage in the joints. An X-ray based imaging technique called ‘radiography’ can assess the extent of joint inflammation. Hence the progression of joint damage in RA is called ‘radiographic progression’. It is measured by a scoring system known as Heijde-modified Sharp Score (HSS). This indicates the degree of erosion and joint space narrowing (JSN – narrowing of space between the bones) caused by the breakdown of joint cartilage.

The effect of mechanical stress on radiographic progression of RA in the hands is not very clear. To gain more insight, further research is needed in this aspect. 

The authors aimed to compare the presence of erosion and JSN between the dominant and non-dominant hand in patients with RA.

194 RA patients were included in this study. 95.4% of patients were right-handed. Hand radiographs (images of joints by radiography) were taken at the time of diagnosis and at 2-year follow-up.

Initial erosion and JSN HSS scores were higher in the dominant hand (5.5) compared to the non-dominant hand (3.7). 5.7% of patients had erosive radiographic progression. 13.4% of patients had JSN progression. Overall progression (both erosion and JSN) occurred in 7.5% of patients. The extent of radiographic progression in 1-year was higher in the dominant hand compared to the non-dominant hand.

Erosive progression in the wrist joint was significantly higher in the dominant hand compared to the non-dominant hand. Erosion in the finger bones and knuckles between the hand and fingers was similar between the dominant and non-dominant hands. Radiographic progression was associated with the dominant hand, a higher level of C-reactive protein (protein that is elevated in inflammation) and higher initial joint damage.  

The authors concluded that joint damage was worse and progressed faster in the dominant hand in early stage RA patients.