The effect of short orthosis for rhizarthrosis on grip and pinch force: a single-case study

Abstract

Objectives: to document the impact of ventral and dorsal short orthosis for rhizarthrosis on grip strength and pinch strength. Methodology: an AB design, single-case, experimental study was performed. Phase A, lasting 4 weeks, consisted of traditional occupational therapy intervention. Phase B, lasting 6 weeks, included the use of ventral or dorsal short orthosis for rhizarthrosis. Two women with rhizarthrosis participated in the study and grip and pinch strength (lateral, tripod and pulp-to-pulp) were evaluated weekly. The Celeration Line and the Two-Standard Deviation Band statistical methods, as well as Visual Analysis, were used for data analysis. Results: the use of ventral short orthosis on dominant hand led to an increase in grip, tripod pinch and pulp-to-pulp pinch strength, as well as strength reduction in lateral pinch. Now, the use of dorsal short orthosis on non dominant hand led to a decrease in lateral, tripod, and pulp-to-pulp pinch strength, with no change in handgrip strength. Conclusion: the results of the study suggest that the use of ventral and dorsal short orthosis on rhizarthrosis interfere with the grip strength and pinch strength. This information can be useful to occupational therapists and other hand rehabilitation professionals that work with these patients to define the type and time of use of the orthosis, minimizing its impact on grip strength.