Upper extremity proprioception and functional performance in adolescents with idiopathic scoliosis: A cross-sectional comparative study

Adolescent idiopathic scoliosis (AIS) is a three-dimensional spinal deformity that may alter trunk alignment, scapulothoracic mechanics, and upper extremity functions; however, evidence regarding upper extremity proprioception and functional performance in individuals with AIS remains limited. This cross-sectional comparative study aimed to investigate differences in upper extremity proprioception, functional performance, and muscle strength between individuals with AIS and healthy peers. The study included 23 adolescent girls (10–17 years) with idiopathic scoliosis (Lenke 1A, 2A, or 3A; Cobb angle 20°–45°) and 23 healthy female controls. Shoulder joint position sense was assessed using the Laser Pointer-Assisted Angle Reproduction Test. Functional performance evaluations included the Closed Kinetic Chain Upper Extremity Stability Test (CKCUEST), open kinetic chain performance (medicine ball throw test), and self-reported upper extremity function (QuickDASH questionnaire). Upper extremity muscle strength was measured using hand-held dynamometry, and between-group comparisons were performed using non-parametric analyses. Individuals with AIS demonstrated significantly lower closed kinetic chain upper extremity performance than controls (p < 0.001). Self-reported upper extremity function also differed significantly between groups (p < 0.001), with higher QuickDASH scores observed in the AIS group and a between-group difference (~18 points) exceeding the minimal clinically important difference. No significant between-group differences were found in shoulder joint position sense at any tested angle or movement plane (all p > 0.05) or upper extremity muscle strength (all p > 0.05), while the between-group difference in open kinetic chain performance did not reach statistical significance (p = 0.089). These findings suggest that the functional consequences of AIS on the upper extremity may be most apparent during dynamic, whole-body tasks rather than in isolated strength or proprioception testing, supporting the inclusion of task-specific functional assessment in the clinical evaluation of this population.