The relationship between toe-out angle during gait and progression of medial tibiofemoral osteoarthritis.
Chang A, Hurwitz D, Dunlop D, Song J, Cahue S, Hayes K, Sharma L.
Ann Rheum Dis. 2007 Oct;66(10):1271-5. Epub 2007 Jan 31.
Department of Physical Therapy and Human Movement Sciences, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611, USA.
BACKGROUND: A greater knee adduction moment increases risk of medial tibiofemoral osteoarthritis (OA) progression. Greater toe-out during gait shifts the ground reaction force vector closer to the centre of the knee, reducing the adduction moment. The present study was designed to test whether greater toe-out is associated with lower likelihood of medial OA progression. METHODS: Baseline assessments included: kinematic/kinetic gait parameters using an optoelectronic camera system, force platform and inverse dynamics to calculate three-dimensional external knee moments; toe-out angle (formed by the line connecting heel strike and toe-off plantar surface centres of pressure and the forward progression line; knee pain; and full-limb alignment. Knee x-rays (semi-flexed) were obtained at baseline and at 18 months, with progression noted as medial joint space grade worsening. With logistic regression, odds ratios (ORs) for progression/5 degrees toe-out were estimated. RESULTS: In the 56 subjects (59% women, mean age 66.6 years, body mass index (BMI) 29), baseline toe-out angle was less in knees with than without progression (difference -4.4, 95% CI -8.5 to -0.3). Greater toe-out was associated with reduced likelihood of progression (OR 0.60, 95% CI 0.37 to 0.98). Adjusting for age, gender, BMI, pain severity and disease severity, the OR was 0.62, 95% CI 0.36 to 1.06. Adjusting for adduction moment (second peak), the OR was 0.72, 95% CI 0.40 to 1.28. CONCLUSIONS: Osteoarthritic knees that progressed had less toeing-out than knees without progression. Greater toe-out was associated with a lower likelihood of progression. Adjustment for covariates did not alter the OR, although the 95% CI included 1. Further adjustment for adduction moment did alter the OR, consistent with the possibility that a mechanism of the effect may be via lowering of the adduction moment.
- Research Support, N.I.H., Extramural
- Disease Progression
- Knee Joint/physiopathology
- Osteoarthritis, Knee/*physiopathology
- P60 AR48098/AR/United States NIAMS
- R01 48748/United States PHS
- R01 AR46225/AR/United States NIAMS
- RR00048/RR/United States NCRR
Date of Electronic Publication: 2007 Jan 31
Publication Status: ppublish
PMID: 17267516 [PubMed - indexed for MEDLINE]