Differences in tibial subchondral bone structure evaluated using plain radiographs between knees with and without cartilage damage or bone marrow lesions - the Oulu Knee Osteoarthritis study

Objectives To investigate whether subchondral bone structure from plain radiographs is different between subjects with and without articular cartilage damage or bone marrow lesions (BMLs). Methods Radiography-based bone structure was assessed from 80 subjects with different stages of knee osteoarthritis using entropy of Laplacian-based image (E-Lap) and local binary patterns (E-LBP), homogeneity index of local angles (HIAngles,mean), and horizontal (FDHor) and vertical fractal dimensions (FDVer). Medial tibial articular cartilage damage and BMLs were scored using the magnetic resonance imaging osteoarthritis knee score. Level of statistical significance was set to p < 0.05. Results Subjects with medial tibial cartilage damage had significantly higher FDVer and E-LBP as well as lower E-Lap and HIAngles,mean in the medial tibial subchondral bone region than subjects without damage. FDHor, FDVer, and E-LBP were significantly higher, whereas E-Lap and HIAngles,mean were lower in the medial trabecular bone region. Subjects with medial tibial BMLs had significantly higher FDVer and E-LBP as well as lower E-Lap and HIAngles,mean in medial tibial subchondral bone. FDHor, FDVer, and E-LBP were higher, whereas E-Lap and HIAngles,mean were lower in medial trabecular bone. Conculations Our results support the use of bone structural analysis from radiographs when examining subjects with osteoarthritis or at risk of having it.