Quantifying gait and mobility in severe idiopathic scoliosis with inertial measurement technology.

BACKGROUND: Adolescent idiopathic scoliosis (AIS) is the most common spinal deformity in adolescents. Severe curves (> 40°) can alter spinopelvic balance and gait mechanics, although few studies have objectively quantified these effects. To analyze gait characteristics, pelvic mobility, and lumbopelvic motion patterns in patients with severe AIS compared to healthy controls using inertial measurement unit (IMU) technology, and to explore correlations between radiological and gait parameters. METHODS: A prospective study was conducted including 35 preoperative AIS patients (Cobb > 40°) and 34 age-matched healthy controls. Each participant underwent gait analysis using a single IMU (BTS G-Sensor) performing three standardized tests: Up and Go, Walk, and 6-Minute Walk. Radiological parameters (Cobb angles, pelvic incidence, tilt, and sacral slope) were recorded through Xray. Statistical comparisons were performed. RESULTS: Among the 35 AIS patients, Lenke type 1 (45.7%) and type 3 (31.4%) curves were the most frequent, with types 2, 4, 5, and 6 observed less commonly. AIS patients showed greater accelerations during standing-up (4.63 ± 1.98 m/s²) and sitting-down (5.12 ± 1.85 m/s²) transitions with reduced trunk flexion (31.00 ± 8.67°) and extension (11.51 ± 8.42º) ranges. They also exhibited significantly lower gait symmetry (92.51 ± 5.01%) and smaller pelvic tilt range (6.33 ± 2.74°). AIS patients have also significantly lower gait speed (1.31 ± 0.10 m/s) and distance walked in the 6-Minute Walk (421.16 ± 65.12 m). CONCLUSIONS: Severe AIS alters lumbopelvic rhythm and gait kinematics, producing compensatory patterns characterized by increased pelvic mobility and reduced trunk flexion. IMU-based motion analysis enables objective and reproducible evaluation of these biomechanical changes, offering a valuable clinical tool for preoperative assessment and rehabilitation planning.