Sustained increase of pinch strength after traction treatment for symptomatic distal interphalangeal joint osteoarthritis.

Background: Symptomatic distal interphalangeal joint osteoarthritis is a common joint disease that causes hand disability and reduces quality of life. There are few conservative treatment options for this condition. The purpose of this study was to investigate the effect of traction treatment on symptomatic distal interphalangeal joint osteoarthritis.

Methods: This prospective, longitudinal study involved multiple time-series observations and within-subject controls. The most painful distal interphalangeal joints in patients with hand osteoarthritis were treated by daily, 15-min joint traction at home using a finger trap orthosis. The corresponding contralateral digits were used as within-subject controls. The primary outcome measure was two-point pinch strength, and the secondary outcome measures were radiographic findings and treatment adherence. Longitudinal and pairwise comparison analyses of the treated and control digits examined improvements in two-point pinch strength at months 1, 3, and 6 from baseline. The durability of treatment effects after treatment discontinuation was investigated at month 12.

Results: Eighteen treated digits and 18 corresponding control digits were eligible for analysis. There was a significant increase in two-point pinch strength after 1-month traction, and this increase was maintained until month 6 despite the absence of radiographic changes. Compared to controls, significant improvement in two-point pinch strength relative to baseline was seen at every observation time point, with a moderate to large effect size. There was no time-treatment interaction. Treatment adherence was high. At months 3 and 6, around 60-80 % of digits were voluntarily treated. Pinch strength was comparable between months 6 and 12, with greater improvement than in the control group.

Conclusion: Joint traction treatment can improve pinch strength in symptomatic distal interphalangeal joint osteoarthritis. Larger, randomized studies on traction treatment and the effect on hand function are warranted.