Assessing the Acetabular Cup Implant Primary Stability by Impact Analyses: A Cadaveric Study

Area of Science:

• Orthopedic Surgery
• Biomedical Engineering
• Surgical Materials Science

Background:

• Primary stability of acetabular cup (AC) implants is crucial for cementless hip surgery success.
• Assessing AC implant stability is challenging due to the complex bone-implant interface.
• Balancing implant stability and bone fracture risk during AC insertion is critical.

Purpose of the Study:

• To evaluate the potential of impact signal analysis for assessing primary acetabular cup implant stability.
• To correlate impact signal indicators with biomechanical pull-out forces in cadaveric specimens.

Main Methods:

• Acetabular cup implants of various sizes were inserted into 12 cadaveric hips (86 configurations).
• Impact signals were recorded using a force-sensored hammer impacting the implant.
• An indicator (I) was derived from impact momentum, with an averaged value (IM) determined for each configuration.
• Tangential pull-out biomechanical tests measured the ultimate pull-out force (F).

Main Results:

• A significant correlation (R² = 0.69) was observed between the impact signal indicator (IM) and pull-out force (F) across all configurations.
• Analysis of impact signals from cadaveric specimens provides valuable information on AC implant biomechanical stability.

Conclusions:

• Impact signal analysis is a viable method for assessing acetabular cup implant stability.
• These findings support the development of a novel medical device for intraoperative use.
• Such a device could enable orthopedic surgeons to customize surgical protocols on a patient-specific basis.