Quantification of soft tissue artifacts using CT registration and subject-specific multibody modeling.

Area of Science:

• Orthopedics
• Biomechanics
• Medical Imaging

Background:

• Gait analysis shows potential for quantitative preoperative planning in total hip arthroplasty (THA).
• Soft tissue artifacts (STAs) often cause distortions, leading to unreliable hip kinematic data for surgical planning.

Purpose of the Study:

• To develop and validate a novel motion capture framework to accurately measure hip kinematics by mitigating STAs.
• To assess the influence of STAs on hip joint motion during gait and squatting activities.

Main Methods:

• Combined computed tomography (CT)-based postural calibration with subject-specific multibody dynamics modeling.
• Developed subject-specific hip joint models from CT data and utilized spring-dashpot elements to represent thigh STAs.
• Employed smooth orthogonal decomposition and least squares optimization to identify and compensate for STA effects.

Main Results:

• The CT-assisted motion tracking framework successfully identified STA influences during gait and squatting.
• STA effects were observed to significantly alter maximal pelvic tilt and hip rotations during squatting.
• The developed method provides a practical alternative to dual fluoroscopic imaging for preoperative planning in robot-assisted THA.

Conclusions:

• The novel framework effectively corrects for STAs in hip kinematic measurements.
• Accurate hip kinematics are crucial for effective preoperative planning in total hip arthroplasty.
• This CT-based approach offers a practical, non-invasive solution for evaluating hip joint motion.