Characterising acetabular component orientation with pelvic motion during total hip arthroplasty

Area of Science:

• Orthopedic Surgery
• Biomechanical Engineering
• Medical Imaging

Background:

• Suboptimal acetabular component placement in total hip arthroplasty (THA) is linked to impingement, dislocation, and wear.
• Intraoperative pelvic motion is a significant source of surgeon error, leading to acetabular cup malposition.

Purpose of the Study:

• To characterize the quantitative relationship between intraoperative pelvic rotation and postoperative acetabular cup orientation.
• To provide data for developing strategies to mitigate malpositioning caused by pelvic motion during THA.

Main Methods:

• A custom device enabled cadaveric pelvis rotation along three axes (roll, tilt, pitch) with a fixed acetabular cup.
• Motion capture technology (Optotrak Certus) tracked component and pelvic marker movements.
• Computed tomography (CT) 3D reconstruction validated results across varied pelvis and implant sizes.

Main Results:

• Pelvic roll, tilt, and pitch demonstrated a non-linear effect on final cup anteversion and inclination.
• Each degree of pelvic roll, tilt, and pitch induced specific changes in radiographic anteversion and inclination.
• These orientation changes were consistent across different pelvis and cup sizes.

Conclusions:

• Intraoperative pelvic motion substantially influences final acetabular component position in THA.
• Adjusting component placement based on real-time pelvic motion can enhance postoperative accuracy.
• This research supports the development of intraoperative navigation aids to improve THA outcomes.