For patients with hand osteoarthritis (OA), inflammation in both the interphalangeal and first carpometacarpal (CMC-1) joints is associated with pain in the same joint, according to results published in Arthritis Research & Care. However, the results indicated that only CMC-1 joint inflammation was associated with hand pain, reduced physical function, and lower grip strength, indicating that CMC-1 inflammation may be an important treatment target.
The study included participants with hand OA (n=290). Participants underwent an ultrasound examination of the bilateral interphalangeal and CMC-1 joints.
The researchers used logistic regression analyses with generalized estimating equations to examine whether grade 0-3 grey-scale synovitis and power Doppler activity were associated with pain in the same joint. They used linear regression analyses to examine whether the degree of inflammation was associated with numeric rating scale (NRS) and Australian/Canadian (AUSCAN) hand pain, AUSCAN physical function, and grip strength. After adjusting for age, sex, body mass index, psychosocial factors, use of analgesics, and osteophytes, separate analyses were made for interphalangeal and CMC-1 joints.
The results indicated that increasing grey-scale synovitis severity was associated with higher odds of pain on palpation in both interphalangeal (grade 2-3: odds ratio, 3.17; 95% CI, 2.35-4.28) and CMC-1 joints (grade 2-3: odds ratio, 4.40; 95% CI, 2.10-9.24). The researchers found similar associations for power Doppler activity and joint pain for the previous 24 hours and 6 weeks.
In CMC-1, power Doppler activity was linked with overall hand pain/physical function and lower grip strength.
The researchers noted potential study limitations resulting from the limited experience of the medical student who performed the ultrasounds and the use of only 1 ultrasonographer.
“Our results suggest that treating inflammation may be especially important in the CMC-1 joints,” the researchers wrote.
Fjellstad CM, Mathiessen A, Slatkowsky-Christensen B, Kvien TK, Hammer HB, Haugen IK. Associations between ultrasound-detected synovitis, pain and function in interphalangeal and thumb base osteoarthritis: data from the Nor-Hand study [published online August 17, 2019]. Arthritis Care Res. doi:10.1002/acr.24047