Quantitative regional and sub-regional analysis of femoral and tibial subchondral bone mineral density (sBMD) using computed tomography (CT): comparison of non-osteoarthritic (OA) and severe OA knees

Abstract

sBMD locally differs between non-OA and OA knees, in agreement with prior knowledge on biomechanics. CT proved to be a valuable tool for 3D analysis of femoral and tibial sBMD, which can be used in future studies to describe the chronology of sBMD alterations and improve our understanding of the role of subchondral bone in knee OA.

Relationships between cartilage thickness and subchondral bone mineral density in non-osteoarthritic and severely osteoarthritic knees: In vivo concomitant 3D analysis using CT arthrography

“…This study builds on previous work showing that sBMD can be assessed tri-dimensionally using CT data 19 . In the current work, we used the ability of CT arthrography to allow simultaneous analysis of sBMD and CTh in high resolution, and in 3D, to assess the correlations between these variables.…”

“…First, bivariate analyses were performed using Pearson correlations. Since sBMD and CTh have been associated with age, gender and, body morphology 19,43,44 , multivariable regressions were also performed with age, gender, biepicondylar femoral diameter and femorotibial angle as confounders. Specifically, a multivariable model was calculated for each combination of dependent (sBMD measure or ratio) and independent (CTh measure or ratio in the same region or subregion) variables using a backward stepwise regression with forced entry for the four adjustment variables in addition to the independent variable.…”

“…The osteophytes were excluded from the bone models. Then, an sBMD value was calculated for each subchondral point of the 3D femur models by averaging the CT intensity in the first 3 mm of bone 17,19 . A penetration of 3 mm was selected to strictly measure the BMD of the subchondral bone 17,38,39 .…”

“…This is noteworthy because sBMD has been proposed as a potential actor in the pathogenesis of cartilage degeneration 20,21 . So far, dual energy X-ray absorptiometry (DXA) has been the modality most commonly used to quantify bone mineral density, but due to its technical limitations, including its low resolution and projectional nature, DXA does not permit detailed analysis of the bone mineral density along the articular surfaces of the knee joint and consequently is of limited use for the assessment of sBMD 19 .…”

Three‐dimensional mapping of the joint space for the diagnosis of knee osteoarthritis based on high resolution computed tomography: Comparison with radiographic, outerbridge, and meniscal classifications

“…13 Moreover, the use of 3 Tesla machines is often necessary to obtain good signal to noise ratio. 13 Imaging by CT is not used in routine clinical investigations of knee disease because a significant radiation dose is delivered; however, it is known to provide excellent visualization of bone and calcified tissue, and its use has been proposed to evaluate calcium deposition, 18 quantitative analysis of regional bone mineral density, 19 and semi-quantitative scoring of cartilage lesions with arthrography. 20 High resolution peripheral QCT (HR-pQCT) images are clinically used to study separately trabecular bone density and micro-architecture and cortical bone density, thickness, and porosity.…”