Association of flat feet with knee pain and cartilage damage in older adults

Authors

  • K. Douglas Gross,

    Corresponding author
    1. Massachusetts General Hospital Institute of Health Professions and Boston University School of Medicine, Boston, Massachusetts
    • Boston University School of Medicine, 650 Albany Street, Suite X200, Boston, MA 02118
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  • David T. Felson,

    1. Boston University School of Medicine, Boston, Massachusetts
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  • Jingbo Niu,

    1. Boston University School of Medicine, Boston, Massachusetts
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  • David J. Hunter,

    1. Royal North Shore Hospital and Northern Clinical School, University of Sydney, Sydney, Australia
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  • Ali Guermazi,

    1. Boston University School of Medicine, Boston, Massachusetts
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    • Dr. Roemer owns stock and/or holds stock options in Boston Imaging Core Lab, LLC.

  • Frank W. Roemer,

    1. Boston University School of Medicine, Boston, Massachusetts
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    • Because Dr. Hannan is Editor of Arthritis Care & Research, review of this article was handled by the previous Editors of Arthritis Care & Research.

  • Alyssa B. Dufour,

    1. Hebrew SeniorLife, Boston, and Harvard Medical School, Roslindale, Massachusetts
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  • Rebekah H. Gensure,

    1. Hebrew SeniorLife, Boston, and Harvard Medical School, Roslindale, Massachusetts
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  • Marian T. Hannan

    1. Hebrew SeniorLife, Boston, and Harvard Medical School, Roslindale, Massachusetts
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    • Dr. Guermazi received consultancy fees (more than $10,000 each) from Stryker and Novartis, and (less than $10,000 each) from Merck Serono, Facet Solutions, and Genzyme, owns stock and/or holds stock options in Synarc, and is president of Boston Imaging Core Lab, LLC.


Abstract

Objective

To assess the cross-sectional relation of planus foot morphology to ipsilateral knee pain and compartment-specific knee cartilage damage in older adults.

Methods

In the Framingham Studies, we adapted the Staheli Arch Index (SAI) to quantify standing foot morphology from pedobarographic recordings. We inquired about knee pain and read 1.5 T magnetic resonance image (MRI) scans using the Whole-Organ MRI Score. Logistic regression compared the odds of knee pain among the most planus feet to the odds among all other feet, and estimated odds within categories of increasing SAI. Similar methods estimated the odds of cartilage damage in each knee compartment. Generalized estimating equations adjusted for age, sex, body mass index, and nonindependent observations.

Results

Among 1,903 participants (56% women, mean ± SD age 65 ± 9 years), 22% of knees were painful most days. Cartilage damage was identified in 45% of medial tibiofemoral (TF), 27% of lateral TF, 58% of medial patellofemoral (PF), and 42% of lateral PF compartments. Compared with other feet, the most planus feet had 1.3 times (95% confidence interval [95% CI] 1.1–1.6) the odds of knee pain (P = 0.009), and 1.4 times (95% CI 1.1–1.8) the odds of medial TF cartilage damage (P = 0.002). Odds of pain (P for linear trend = 0.05) and medial TF cartilage damage (P for linear trend = 0.001) increased linearly across categories of increasing SAI. There was no association between foot morphology and cartilage damage in other knee compartments.

Conclusion

Planus foot morphology is associated with frequent knee pain and medial TF cartilage damage in older adults.

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