Reduction in Thigh Muscle Strength Occurs Concurrently but Does Not Seem to Precede Incident Knee Pain in Women: Data From the Osteoarthritis Initiative Cohort

Am J Phys Med Rehabil. 2020 Jan;99(1):33-40. doi: 10.1097/PHM.0000000000001271.


Objective: The aim of the study was to investigate whether muscle strength declines before or concurrent with incident knee pain in subjects with and without radiographic knee osteoarthritis.

Design: Osteoarthritis initiative participants with incident knee pain (occurrence of infrequent/frequent knee pain during the past 12 mos at two consecutive follow-up time points (either years Y3 + Y4 or Y4 + Y5) were compared with controls (no incident knee pain) with 2-yr changes in knee extensor strength during BL➔Y2 (before) and Y2➔Y4 (concurrent).

Results: Two hundred two knees (49% women, 40% radiographic knee osteoarthritis) displayed incident pain, and 439 did not (46% women, 23% radiographic knee osteoarthritis). Women with radiographic knee osteoarthritis displayed a significantly greater (P = 0.04) reduction in knee extensor strength concurrent with incident pain compared with controls (mean = -17.6 N vs. +4.5 N), but men did not. A similar trend was observed in women without radiographic knee osteoarthritis, but this was not statistically significant (P = 0.08). There was no significant relationship with change in extensor strength before incident pain (P ≥ 0.43).

Conclusions: These results suggest that in women, incident knee pain is accompanied by a concurrent reduction in knee extensor strength, whereas loss in strength does not precede incident knee pain. The findings encourage interventional studies that attempt to attenuate a decline in extensor strength once knee symptoms occur.

Trial registration: NCT00080171.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aged
  • Arthralgia / epidemiology*
  • Arthralgia / etiology
  • Comorbidity
  • Female
  • Humans
  • Incidence
  • Knee Joint*
  • Male
  • Middle Aged
  • Muscle Strength
  • Muscle Weakness / epidemiology*
  • Muscle Weakness / etiology
  • Osteoarthritis, Knee / complications*
  • Osteoarthritis, Knee / diagnostic imaging
  • Osteoarthritis, Knee / physiopathology
  • Radiography
  • Sex Factors
  • Thigh*

Associated data