Usefulness of the “PET bottle cap test”as simple evaluation of upper limb functions

A longitudinal study of patients with upper limb fractures

Abstract

This study aimed to longitudinally assess the PET Bottle Cap Test (PCT) in 34 patients with upper extremity fractures, with a mean age of 66. 3 ±12. 6 years and 82% female participants, including 14 with proximal humerus fractures and 20 with distal radius fractures. The objective was to elucidate the application and limitations of the PCT. PCT, peg test, grip strength, pinch strength, unbuttoning time, changing one's cardigan time, and Hand20 were measured．A two-way analysis of variance was performed, considering the fracture site (humerus and radius fracture groups) and the assessment time points (initial and one month later). Additionally, correlation analysis was conducted between the PCT and other assessments at each point. The results revealed significant main effects of PCT, the peg test, grip strength, pinch strength, unbuttoning time, changing one's cardigan time, and Hand20 (p<0. 05), predominantly concerning the time factor，and grip strength, pinch strength (p<0. 05), predominantly concerning the fracture site factor. Notably, the PCT demonstrated significant correlations with peg test (initial：r=-0. 359, one month later：r=-0. 396), unbuttoning time (r=0. 739, r=0. 608), and changing one’s cardigan time (r=0. 52, r=0. 619) at both time points. These findings indicate that the PCT can effectively reflect temporal changes in the functional ability of the affected side and in upper limb manipulation skills of both hands, independent of the fracture site. Consequently, the PCT emerges as a valuable method for assessing bimanual movements and the ability of the affected side in fine motor skills and activities of daily living throughout the year.