Acoustic-based intraoperative assessment of femoral stem initial stability in cementless THA via sensitive frequency band identification

Intraoperative assessment of femoral stem initial stability in cementless total hip arthroplasty (THA) predominantly relies on subjective tactile and auditory feedback, which lacks standardization and increases complication risks. This study develops a quantitative framework to identify sensitive acoustic frequency bands characterizing the bone-implant fixation state. Specifically, we acquired high-fidelity acoustic signals from 118 primary cementless THA procedures. Utilizing a statistical difference analysis framework, we identified two distinct sensitive bands (640-1920 Hz and 3460-3560 Hz) to extract Band Power Fraction (BPF) features. Machine learning evaluation demonstrated that these bands significantly outperform traditional empirical partitioning, achieving a classification accuracy of 0.816 ± 0.028, which improved to 0.834 ± 0.042 after feature fusion. Furthermore, stratified validation confirmed high consistency across diverse bone qualities and implant designs (Summit and Corail). While robust under steady-state Gaussian noise, the system exhibited sensitivity to non-steady-state speech interference. In conclusion, the identified sensitive bands effectively reflect the mechanical evolution of the bone-implant interface, providing a physically interpretable decision-support tool for enhancing surgical safety.