Quadriceps Strength and Osteoarthritis Progression in Malaligned and Lax Knees

  1. Leena Sharma, MD;
  2. Dorothy D. Dunlop, PhD;
  3. September Cahue, BS;
  4. Jing Song, MS; and
  5. Karen W. Hayes, PhD
  1. From Northwestern University, Chicago, Illinois.

    Abstract

    Background: Quadriceps muscle strengthening is a common goal in the management of knee osteoarthritis. In healthy knees, strength protects against new osteoarthritis. In arthritic knees, greater strength may protect joints and thereby delay osteoarthritis progression. Alternatively, in certain joint environments, such as malalignment or laxity, greater strength may translate into damaging joint reaction forces. The relationship between quadriceps strength and progression of knee osteoarthritis may differ according to these factors.

    Objective: To determine whether greater quadriceps strength is associated with greater probability of tibiofemoral osteoarthritis progression in malaligned knees and in high-laxity knees.

    Design: Prospective, longitudinal cohort study.

    Setting: Academic medical center.

    Participants: 237 persons with primary knee osteoarthritis, definite tibiofemoral osteophytes, and at least some difficulty with knee-requiring activity. Two hundred thirty completed the 18-month evaluation. The current study primarily involved those without advanced osteoarthritis in either knee (n = 171).

    Measurements: Quadriceps strength, knee laxity and alignment, and osteoarthritis progression.

    Results: The predicted probability of tibiofemoral progression was 0.153 (95% CI, 0.100 to 0.228) in high-strength knees and 0.098 (CI, 0.061 to 0.155) in low-strength knees. In malaligned knees, high strength was associated with a significant increase (P = 0.03) in the likelihood of progression (predicted probability, 0.406 [CI, 0.226 to 0.615] vs. 0.187 [CI, 0.081 to 0.375] in high-strength vs. low-strength knees). Strength was also associated with increased likelihood of progression in high-laxity knees (P = 0.003 when high laxity was defined as ≥ 6.75 degrees). The probability of patellofemoral progression did not differ between high- and low-strength knees in the full sample or within subsets.

    Conclusions: Greater quadriceps strength at baseline was associated with increased likelihood of tibiofemoral osteoarthritis progression in malaligned knees and lax knees. Subset-specific approaches beyond strengthening exercises should be developed to enhance joint-protective muscle activity.

    Article and Author Information

    • Grant Support: By National Institutes of Health grant AR-30692, National Institutes of Health/National Center for Research Resources grant RR-00048, and the Arthritis Foundation.

    • Potential Financial Conflicts of Interest: None disclosed.

    • Requests for Single Reprints: Leena Sharma, MD, Division of Rheumatology, Feinberg School of Medicine, Northwestern University Medical School, 300 East Superior Avenue, Tarry Building 3-715, Chicago, IL 60611.

    • Current Author Addresses: Dr. Sharma and Ms. Cahue: Department of Medicine, Feinberg School of Medicine, Northwestern University Medical School, 300 East Superior Avenue, Tarry Building 3-715, Chicago, IL 60611.

    • Dr. Dunlop and Ms. Song: Institute for Health Services Research and Policy Studies, Northwestern University, 339 East Chicago Avenue, Wieboldt Hall, Room 717, Chicago, IL 60611.

    • Dr. Hayes: Department of Physical Therapy and Human Movement Sciences, Northwestern University Medical School, 645 North Michigan Avenue, Suite 1100, Chicago, IL 60611.

    • Author Contributions: Conception and design: L. Sharma, S. Cahue, K.W. Hayes.

    • Analysis and interpretation of the data: L. Sharma, D.D. Dunlop, J. Song.

    • Drafting of the article: L. Sharma, S. Cahue.

    • Critical revision of the article for important intellectual content: L. Sharma, D.D. Dunlop, K.W. Hayes.

    • Final approval of the article: L. Sharma, D.D. Dunlop, K.W. Hayes.

    • Provision of study materials or patients: S. Cahue.

    • Statistical expertise: D.D. Dunlop, J. Song.

    • Obtaining of funding: L. Sharma.

    • Administrative, technical, or logistic support: L. Sharma, J. Song, K.W. Hayes.

    • Collection and assembly of data: L. Sharma, S. Cahue, K.W. Hayes.

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    1. Ann Intern Med April 15, 2003 vol. 138 no. 8 613-619
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