A biomechanical comparison of movement strategies during the timed up and go test in patients with femoral neck and trochanteric fractures.

BACKGROUND

Proximal femoral fractures show heterogeneous functional recovery, but it is unclear whether movement strategies during the Timed Up and Go (TUG) test differ between femoral neck (FN) and intertrochanteric (IT) fractures.

RESEARCH QUESTION: To determine whether pelvic kinematics during the TUG test differ between FN and IT fractures when assessed using inertial measurement units (IMUs).

METHODS

Forty postoperative patients with proximal femoral fractures undergoing inpatient rehabilitation performed the TUG test at maximal speed while wearing IMUs on the pelvis and both feet. Peak pelvic accelerations in the medial-lateral, anterior-posterior, and vertical directions and pelvic angular velocities (roll, pitch, yaw) were extracted for sit-to-stand, walking, turning, and sit-down phases. Linear mixed-effects models compared FN and IT groups across phases, adjusting for demographic, radiographic, and clinical covariates.

RESULTS

Compared with FN fractures, IT fractures showed greater lateral pelvic acceleration during walking and sit-down phase. Greater lateral pelvic acceleration during walking and greater pelvic pitch angular velocity during sit-to-stand were also observed, but these findings were interpreted cautiously because the 95% confidence intervals included zero.

SIGNIFICANCE: IMU-based analysis of pelvic motion during the TUG test identified between-group differences in movement strategy after proximal femoral fractures, particularly during functional transitions. These findings suggest that IMU-based TUG assessment may provide clinically relevant information beyond conventional performance measures and may support more individualized rehabilitation planning after hip fracture surgery.