Session Information
Session Type: Abstract Submissions (ACR)
Background/Purpose:
Knee osteoarthritis (OA) manifests disproportionately in women and the etiology remains unclear. Bone shape has been found to be associated the development of knee OA in prior studies. To further explore this relationship, we examined the association of proximal tibia shape with sex to begin to understand these relationships.
Methods:
We used information from the NIH-funded Osteoarthritis Initiative (OAI), a cohort of persons aged 45-79 at baseline who either had symptomatic knee OA or were at high risk of it. We randomly sampled knees from women and men from the OAI cohort who had Kellgren/Lawrence grade of 0 in central readings on baseline radiograph who were aged between 45 and 60 years. Using baseline radiographs we characterized proximal tibia shape using Active Shape Modeling to generate the modes of shape difference across our selected population. Given that all modes were normally distributed, we performed linear regression to examine the association of proximal tibia shape with sex, adjusting for age, race, body mass index (BMI) and clinic site. Beta estimates and 95% confidence intervals report the amount of standard deviation increase or decrease in mode shape among women compared to men.
Results:
The mean age of subjects in the analysis was 52.7 years (±4.3 SD) for both men and women. There were 191 female knees and 149 male knees. 10 modes were derived for tibial shape. The 10 modes described 95.5% of the total variance in proximal tibia shape in the population sampled. Mode 2 had the highest significance for association with sex (p=0.009). (See table for beta estimates and description of first 5 modes.)
Conclusion:
Tibial knee shape may be associated with sex. Further work to understand how these shape modes are associated with knee OA, and whether they can explain differences in prevalence of OA by sex, is warranted.
|
Mode |
Adjusted Beta (95%CI) |
P-value |
Mode Description – primary alteration of shape with increased SD weighting |
|
1 |
-0.2 (-0.42 to 0.02) |
0.0797 |
Decreased concavity, elevation of lateral compartment plateau, and decreased shaft width |
|
2 |
-0.29 (-0.51 to -0.07) |
0.0091 |
Tibial head shifted laterally in relation to the shaft, and head width increased. The lateral tibial plateau is more concave |
|
3 |
-0.22 (-0.43 to -0.01) |
0.0376 |
Slightly increased tibial width, depression of medial plateau and elevation of lateral plateau |
|
4 |
-0.23 (-0.45 to -0.02) |
0.0324 |
Increased concavity of medial compartment and elevation of medial lip, with broadening of lateral plateau |
|
5 |
-0.01 (-0.23 to 0.2) |
0.9097 |
Narrowed medial plateau width and slight elevation of lateral plateau |
Disclosure:
B. L. Wise,
Pfizer, Inc.,
2;
F. Liu,
None;
N. Parimi,
None;
J. A. Lynch,
None;
Y. Zhang,
None;
L. Kritikos,
None;
N. E. Lane,
None.
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-association-of-proximal-tibia-shape-with-sex-the-osteoarthritis-initiative/