Raman spectroscopy reveals differences in molecular structure between human femoral heads affected by steroid-associated and alcohol-associated osteonecrosis.

<bold>Purpose: </bold>The purposes of this study were to document novel Raman spectroscopic findings in femoral heads affected by osteonecrosis and to identify molecular structure differences based on aetiology.<bold>Methods: </bold>We obtained 13 femoral heads with osteonecrosis from 13 different patients who underwent total hip arthroplasty. Comparisons were made between the viable zones of each femoral head examined. The samples were scanned with X-ray micro-CT for structural mapping and a central coronal section slab was prepared for Raman spectroscopy and histological analyses. Raman spectra were collected at different locations, including the viable and necrotic zones of the femoral head, using a highly spectrally resolved Raman microprobe.<bold>Results: </bold>Significant alterations in the spectral morphology in the high wavenumber region were found, with a pronounced inhibition of peculiar lipid signals in the frequency interval 2851 ~ 2890 cm-1 and at ~ 1750 cm-1. The necrotic zone in steroid-associated osteonecrosis showed an increase in the ratio of lipid-related bands to protein-related bands, while alcohol-associated osteonecrosis exhibited a decrease in this ratio.<bold>Conclusions: </bold>We systematically found a decrease in Raman intensity for sphingomyelin and phenylalanine fingerprint bands in the necrotic zones, and these differences may be related to the etiology of osteonecrosis. [ABSTRACT FROM AUTHOR]