B-23 Free Communication/Poster - Biomechanics: MAY 27, 2009 1:00 PM - 6:00 PM ROOM: Hall 4F
Quadriceps weakness has been implicated as a potential risk factor for the development and progression of knee osteoarthritis (OA); however minimal data are available to demonstrate quadriceps dysfunction is present during the early stages of the disease. Further, if quadriceps weakness is a major determinant of disease progression it follows that muscle strength may diminish as OA severity worsens, but evidence supporting this hypothesis is lacking.
PURPOSE: To determine if quadriceps strength decreases as OA severity increases.
METHODS: Ninety-one women (age 56.49±2.8 yrs; height 1.63±0.07 m; mass 83.51±14.12 kg) participated in this study and underwent radiographic evaluation and strength testing. Semi-flexed standing A-P x-rays were taken and graded for tibiofemoral OA severity using the Kellgren-Lawrence scale. Quadriceps strength was assessed isometrically at 90°. Subjects performed three maximum voluntary isometric knee extension contractions and the peak torque values from those trials were averaged. Statistical analysis was performed via a 1×5 ANOVA.
RESULTS: Quadriceps strength (Nm/kg) was not statistically different between the five OA grades (P > 0.05) (Figure 1). While there appears to be a modest decline in strength associated with great knee OA severity (grade 4), the test for trend was not statistically significant (P = 0.09).
CONCLUSION: Contrary to our hypothesis, quadriceps weakness did not worsen with increasing OA severity. Albeit the data come from a cross-sectional study design, absence of a statistically significant association calls into question the importance of quadriceps strength in the etiology of tibiofemoral osteoarthritis.
Supported by The Michigan Arthritis Foundation (N007718)