MR study of longitudinal variations in proximal femur 3D morphological shape and associations with cartilage health in hip osteoarthritis

Abstract

The goal of this study was to use quantitative MRI analysis to longitudinally observe the relationship between 3D proximal femur shape and hip joint degenerative changes. Forty-six subjects underwent unilateral hip MR imaging at three time points (baseline, 18 and 36 months). 3D shape analysis, hip cartilage T1ρ/T2 relaxation time quantification, and SHOMRI MRI grading were performed at each time point. Subjects were grouped based on KL, SHOMRI, and HOOS pain scores. Associations between these score groupings, time, and longitudinal variation in shape, were analyzed using a generalized estimating equation. One-way ANCOVA was conducted to evaluate change in shape as a predictor of the worsening of degenerative changes at 36 months. Our results demonstrated that subjects displayed an increase in the volume of the femoral head and neck (Mode 3) over time. This shape mode was significantly more prevalent in patients that reported pain. Longitudinal changes in this shape mode also served as borderline predictors of elevated T1ρ values (p = 0.055) and of cartilage lesions (p = 0.068). Subjects showed a change in the Femoral Neck Anteversion angle (FNA) over time (Mode 6). This shape mode showed a significant interaction with the presence of cartilage lesions. The results of this study suggest that specific variations in bone shape quantified through 3D-MRI based Statistical Shape modeling show an observable relationship with hip joint compositional and morphological changes. The shapes observed lead to early degenerative changes, which may lead into OA, thus confirming the important role of bone shape changes in the pathogenesis of OA.

Patterns of Change Over Time in Knee Bone Shape Are Associated with Sex

“…Pedoia et al [35] reported shape change in the knee after anterior cruciate ligament injury in young persons, but this study differed in many ways from the current one, particularly in the injury-related context as well as using 3-D MRI rather than radiography. A study examining shape variations over time in a different joint, the hip, reported changes in the volume and shape of the femoral head and neck during 36 months that were associated with hip pain [20]. However, there are multiple differences from the current study: a different joint, much younger participant age (47 years versus almost 60 years), and MRI was used instead of radiography.…”

“…Multiple studies using statistical shape modeling have found that there are sex-related differences in knee shape in individuals with and without knee OA [2,30,34,42,45], but these have all evaluated bone shape at a single timepoint. A few published studies described change in the knee's shape over time [20,35,50]; however, none of these trajectory-related statistical shape modeling studies examined the relation of sex to change in bone shape over time. This may be because all of the studies had relatively small numbers of participants and likely did not have power to identify sex-related differences.…”

“…Wise et al [45] reported that the bone shape at baseline was associated with incident knee OA and in part mediated the relationship between sex and OA. Investigators have also reported associations between bone shape in two and three dimensions with hip OA [13,20,31]. Inamdar et al [20] performed a longitudinal evaluation of the proximal femur's shape using 3-D MRI in males and females and identified two modes that were associated over time with changes in cartilage composition, self-reported pain, and cartilage lesions.…”

Femoral anteversion: significance and measurement

“…This raises the question of whether 50-70 years ago children were more active, and whether we are observing secular rather than within-individual changes. Furthermore, a recent longitudinal study in individuals with hip osteoarthritis suggests that FNA decreases with time over a period of 3 years (Inamdar et al, 2019). This might be due to localised addition of bone on the periosteal surface with increasing age, microfractures or the bony erosion due to the osteoarthritic condition.…”

[18F]‐Sodium Fluoride PET/MR Imaging for Bone–Cartilage Interactions in Hip Osteoarthritis: A Feasibility Study

“…Image analysis was performed automatically using an in‐house program developed in MATLAB (Mathworks, Natick, MA). The 3D shape analysis of the femur was performed using the methods as previously described by Pedoia et al, using an atlas‐based method refined by active contours and 3D statistical shape modeling (SSM) . The SSM has the ability to characterize complex shapes using principal component analysis (PCA).…”