Figure 3
Fourier-transform infrared spectroscopy of biochemical composition of calcium-containing crystals in osteoarthritic knee articular cartilage. (A) Four distinct types of Fourier-transform infrared spectroscopy (FT-IR) spectra in osteoarthritis articular cartilage: carbonated apatite (CA) crystals, calcium pyrophosphate (CPP) crystals, amorphous Ca2+ carbonated phosphate (ACCP) crystals and whitlockite (WH) crystals. (B) Joint-level prevalence of calcium-containing (CaC) crystal types. n, number of patients. (C) Content (%) of crystal type in samples according to joint compartment. Data are mean ± standard error of the mean. LFT, lateral femoro-tibial compartment; MFT, medial femoro-tibial compartment