Per-operative vibration analysis: a valuable tool for defining correct stem insertion: preliminary report.

Area of Science:

• Orthopaedic Surgery
• Biomedical Engineering
• Surgical Technology

Background:

• Current methods for determining total hip replacement stem insertion rely on subjective surgeon feel.
• Custom-made prostheses, while offering optimal fit, increase the risk of per-operative fractures.
• Vibration analysis has shown promise in laboratory settings for detecting optimal stem insertion.

Purpose of the Study:

• To evaluate the first per-operative application of vibration analysis for guiding non-cemented custom-made stem insertion.
• To assess the feasibility and potential benefits of vibration analysis in a clinical setting.

Main Methods:

• Thirty patients undergoing total hip replacement with uncemented custom stems were included.
• A shaker and impedance head were used to measure stem frequency response during insertion.
• A computer analyzed the frequency response function, providing feedback to the surgeon.

Main Results:

• A high correlation index (>0.99) was observed in 86.7% of cases between insertion phases.
• Surgeons halted insertion in four cases due to perceived fracture risk, highlighting the system's sensitivity.
• Case studies demonstrated the potential clinical utility of vibration analysis.

Conclusions:

• Intra-operative vibration analysis shows potential as a valuable tool for orthopaedic surgeons.
• The technique can assist in defining the optimal stem insertion endpoint during hip replacement.
• Further development of user-friendly devices is recommended for wider clinical adoption.