Predictive Capacity of Thigh Muscle Strength in Symptomatic and/or Radiographic Knee Osteoarthritis Progression: Data from the Foundation for the National Institutes of Health Osteoarthritis Biomarkers Consortium.
Adam G Culvenor, Wolfgang Wirth, Melanie Roth and 2 others
PMID 27175558WHAT IT FOUND
Thigh muscle strength did not predict combined symptomatic and radiographic knee osteoarthritis progression.
In men, lower baseline knee strength was associated with pain progression without radiographic progression.
Key findings
01In the primary analysis, baseline knee extensor and flexor strength did not predict combined radiographic and symptomatic progression compared with controls without that combination.
02Strength loss from baseline to 24 months was not associated with combined radiographic and symptomatic progression in men or women compared with those without combined progression.
03In men, lower baseline knee extensor strength (adjusted odds ratio 1.7) and lower baseline knee flexor strength (adjusted odds ratio 2.0) predicted isolated symptomatic progression compared with men without symptomatic or radiographic progression.
STILL TO COME
How it was doneWhat they foundWhat it means for PTs
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What it does not show
Not all eligible participants had strength measured at baseline and 24 months, although more than 85% of cases and controls were included. The significant findings in men were secondary subgroup analyses after separate male and female testing, and the authors noted risk of chance findings from multiple comparisons. The study was observational; it did not test whether strength training changes progression. Patellofemoral osteoarthritis was not assessed, so it may have influenced some knee symptoms or progression. Four female flexor strength values below 10 newtons were excluded because they were likely inaccurate.
Declared interests
Adam Culvenor and Melanie Roth reported no conflicts of interest. The article lists N.I.H. extramural and non-U.S. government research support.
The easy way to misread this
Do not conclude that thigh muscle weakness causes knee osteoarthritis progression or that strength training will prevent it. The study observed associations over time, not a treatment effect, and the primary combined progression outcome was null.