Full-Quantitative Analysis of Cementless Stem Hammering Sound Changes During Total Hip Arthroplasty.
Abstract Full-quantitative characterization has not been performed to analyze changes in the hammering sound in cementless hip arthroplasty. We analyzed the frequency spectrum of the hammering sound during stem insertion for 20 cases of uncomplicated cementless total hip arthroplasty for osteoarthritis using a proximal-coated stem. The absolute sound pressure (Pa) and normalized sound pressure of each frequency bands in early and late stage of femoral stem insertion were determined by the Fast Fourier Transform analysis. The absolute sound pressures (Pa) of a majority of frequency bands was significantly higher in the late-stage stem insertion than in the early stage The 1.0–1.5-kHz frequency band showed a significant change in normalized sound pressure in all cases between the early and late stages of stem insertion (p=0.000). The femoral morphology and canal fill ratio were correlated with late stage normalized sound pressure in specific frequency bands. In the 5.0–5.5 kHz band, the Dorr A femoral morphology was significantly higher normalized sound pressure than those in the Dorr B (p=0.004). This study revealed the hammering sound frequency with full-quantitative value altered during cementless stem insertion. Frequency bands of 1.0–1.5 kHz, 5.0–5.5 kHz were the key bands for predicting stem fixation.