PMID- 27836675
OWN - NLM
STAT- MEDLINE
DCOM- 20180314
LR  - 20220317
IS  - 1522-9653 (Electronic)
IS  - 1063-4584 (Print)
IS  - 1063-4584 (Linking)
VI  - 25
IP  - 5
DP  - 2017 May
TI  - Association of knee pain with a reduction in thigh muscle strength - a 
      cross-sectional analysis including 4553 osteoarthritis initiative participants.
PG  - 658-666
LID - S1063-4584(16)30372-7 [pii]
LID - 10.1016/j.joca.2016.10.026 [doi]
AB  - OBJECTIVE: To cross-sectionally determine the quantitative relationship of 
      age-adjusted, sex-specific isometric knee extensor and flexor strength to 
      patient-reported knee pain. METHODS: Difference of thigh muscle strength by age, 
      and that of age-adjusted strength per unit increase on the Western Ontario and 
      McMaster Universities Osteoarthritis Index (WOMAC) knee pain scale, was estimated 
      from linear regression analysis of 4553 Osteoarthritis Initiative (OAI) 
      participants (58% women). Strata encompassing the minimal clinically important 
      difference (MCID) in knee pain were compared to evaluate a potentially non-linear 
      relationship between WOMAC pain levels and muscle strength. RESULTS: In OAI 
      participants without pain, the age-related difference in isometric knee extensor 
      strength was -9.0%/-8.2% (women/men) per decade, and that of flexor strength 
      was -11%/-6.9%. Differences in age-adjusted strength values for each unit of 
      WOMAC pain (1/20) amounted to -1.9%/-1.6% for extensor and -2.5%/-1.7% for flexor 
      strength. Differences in torque/weight for each unit of WOMAC pain ranged 
      from -3.3 to -2.1%. There was no indication of a non-linear relationship between 
      pain and strength across the range of observed WOMAC values, and similar results 
      were observed in women and men. CONCLUSION: Each increase by 1/20 units in WOMAC 
      pain was associated with a  approximately 2% lower age-adjusted isometric extensor and flexor 
      strength in either sex. As a reduction in muscle strength is known to 
      prospectively increase symptoms in knee osteoarthritis (KOA) and as pain appears 
      to reduce thigh muscle strength, adequate therapy of pain and muscle strength is 
      required in KOA patients to avoid a vicious circle of self-sustaining clinical 
      deterioration.
CI  - Copyright (c) 2016 Osteoarthritis Research Society International. Published by 
      Elsevier Ltd. All rights reserved.
FAU - Ruhdorfer, A
AU  - Ruhdorfer A
AD  - Institute of Anatomy, Paracelsus Medical University Salzburg & Nuremberg, 
      Salzburg, Austria. Electronic address: anja.ruhdorfer@pmu.ac.at.
FAU - Wirth, W
AU  - Wirth W
AD  - Institute of Anatomy, Paracelsus Medical University Salzburg & Nuremberg, 
      Salzburg, Austria. Electronic address: wolfgang.wirth@pmu.ac.at.
FAU - Eckstein, F
AU  - Eckstein F
AD  - Institute of Anatomy, Paracelsus Medical University Salzburg & Nuremberg, 
      Salzburg, Austria. Electronic address: felix.eckstein@pmu.ac.at.
LA  - eng
GR  - N01 AR022261/AR/NIAMS NIH HHS/United States
GR  - N01 AR022259/AR/NIAMS NIH HHS/United States
GR  - N01 AR022258/AR/NIAMS NIH HHS/United States
GR  - N01 AR022262/AR/NIAMS NIH HHS/United States
GR  - N01 AR022260/AR/NIAMS NIH HHS/United States
GR  - R01 AR066601/AR/NIAMS NIH HHS/United States
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, N.I.H., Extramural
PT  - Research Support, Non-U.S. Gov't
DEP - 20161109
PL  - England
TA  - Osteoarthritis Cartilage
JT  - Osteoarthritis and cartilage
JID - 9305697
SB  - IM
MH  - Age Factors
MH  - Arthralgia/epidemiology/*physiopathology
MH  - Austria
MH  - Cross-Sectional Studies
MH  - Disease Progression
MH  - Female
MH  - Follow-Up Studies
MH  - Humans
MH  - Incidence
MH  - Knee Joint/*physiopathology
MH  - Male
MH  - Muscle Strength/*physiology
MH  - Osteoarthritis, Knee/epidemiology/*physiopathology
MH  - Pain Measurement
MH  - Quadriceps Muscle/*physiology
MH  - Risk Assessment
MH  - Severity of Illness Index
MH  - Sex Factors
MH  - Thigh
PMC - PMC5403554
MID - NIHMS828734
OTO - NOTNLM
OT  - Knee osteoarthritis
OT  - Minimal clinically important difference
OT  - Thigh muscle strength
OT  - WOMAC knee pain score
COIS- Disclosure of interest Felix Eckstein is CEO and is co-owner of Chondrometrics 
      GmbH, a company providing MR image analysis services. He provides consulting 
      services to MerckSerono, Novartis, Sanofi Aventis, and Abbot. Wolfgang Wirth is 
      part-time employed and is co-owner of Chondrometrics GmbH, and provides 
      consulting services to MerckSerono. Anja Ruhdorfer has no conflicting interests.
EDAT- 2016/11/12 06:00
MHDA- 2018/03/15 06:00
PMCR- 2018/05/01
CRDT- 2016/11/13 06:00
PHST- 2016/06/03 00:00 [received]
PHST- 2016/10/24 00:00 [revised]
PHST- 2016/10/31 00:00 [accepted]
PHST- 2016/11/12 06:00 [pubmed]
PHST- 2018/03/15 06:00 [medline]
PHST- 2016/11/13 06:00 [entrez]
PHST- 2018/05/01 00:00 [pmc-release]
AID - S1063-4584(16)30372-7 [pii]
AID - 10.1016/j.joca.2016.10.026 [doi]
PST - ppublish
SO  - Osteoarthritis Cartilage. 2017 May;25(5):658-666. doi: 
      10.1016/j.joca.2016.10.026. Epub 2016 Nov 9.