Fourier-transform infrared spectroscopy of prevalence and localization of calcium-containing crystals in osteoarthritic knee articular cartilage. (A) Data on preoperative knee joint radiographs (standard anteroposterior and lateral views) were retrieved from clinical charts for 18 of 20 included patients and assessed by one rheumatologist for presence of mineralization in the lateral and/or medial joint spaces to define chondrocalcinosis (first column) After surgery, specimens were harvested and analyzed by Fourier-transform infrared spectroscopy (FT-IR) to assess the presence and type of calcium-containing (CaC) crystals (second column). (B) FT-IR spectroscopy of cartilage samples harvested from the eight to 10 joint areas defined in Figure 1 from all 20 patients to determine the number of areas affected by calcification. n, number of patients. (C) Prevalence of calcifications and proportion of mineral content (D) as determined by FT-IR spectroscopy. Data are mean ± standard error of the mean. ED, intercondyle deep; ES, intercondyle superficial; IntC, intercondyle; LFT, lateral femoro-tibial compartment; MFT, medial femoro-tibial compartment; Surf, superficial.
Nguyen et al. Arthritis Research & Therapy 2013 15:R103 doi:10.1186/ar4283