Effects of cassava wax immersion on pain, pressure pain threshold, and upper extremity function among patients with trigger finger.

BACKGROUND: Trigger finger causes pain and impaired hand function. Ultrasound and paraffin wax are commonly used but have cost and accessibility limitations; cassava wax may be a low-cost alternative, though its effectiveness remains unclear. OBJECTIVE: To evaluate the immediate, short-term, and post-intervention effects of cassava wax immersion combined with ultrasound therapy on pain, pressure pain threshold, and upper extremity function in patients with trigger finger. METHODS: In this single-blind, randomised controlled trial, 38 participants were randomly assigned to two groups ( n = 19 each). The experimental group received ultrasound therapy and cassava wax immersion. The control group received only ultrasound therapy. Both groups were treated three times per week for four weeks. Outcome measures included pain intensity (Visual Analogue Scale), pressure pain threshold, frequency of finger locking, and upper extremity function (Disabilities of the Arm, Shoulder, and Hand questionnaire). RESULTS: Both groups showed significant improvements in all outcomes ( p < 0 . 05 ). Significant between-group differences in pain intensity were observed at all post-treatment time points, with lower pain intensity in the experimental group. The experimental group demonstrated greater increases in pressure pain threshold at immediate and short-term follow-ups and better upper extremity function at short-term and post-intervention follow-ups ( p < 0 . 05 ). CONCLUSION: Ultrasound therapy combined with cassava wax immersion is more effective than ultrasound therapy alone for managing trigger finger, providing greater pain reduction and improved upper extremity function. Cassava wax may be a valuable, natural, and cost-effective option.