Article

OBJECTIVE: To investigate whether relationships between upper leg muscle strength
and activity limitations are non-linear in patients with knee osteoarthritis,
and, if so, to determine muscle strength thresholds for limitations in daily
activities. DESIGN: Baseline data were used for 562 patients with knee
osteoarthritis in the Amsterdam-Osteoarthritis cohort. Upper leg muscle strength
(Nm/kg) was measured isokinetically. Activity limitations were measured with the
timed Get Up and Go test and timed Stair Climb Test, subdivided into stair-ascent
and stair-descent. Linear and non-linear relationships between muscle strength
and activity limitations were evaluated, and thresholds were determined. RESULTS:
Non-linear models improved model fit compared with linear models. The improvement
in percentage variance accounted for was 5.9, 8.2 and 5.2 percentage points for
the timed Get Up and Go, stair-ascent and stair-descent times, respectively.
Muscle strength thresholds were 0.93 Nm/kg (95% confidence interval (95% CI)
0.82-1.04), 0.89 Nm/kg (95% CI 0.77-1.02) and 0.97 Nm/kg (95% CI 0.85-1.11) for
relationships with timed Get Up and Go, stair-ascent and stair-descent times,
respectively. CONCLUSION: In patients with knee osteoarthritis, relationships
between muscle strength and activity limitations are non-linear. Patients with
muscle strength below the described thresholds might benefit more from muscle
strength training to reduce limitations in daily activities than would patients
with muscle strength above the thresholds. Further research is needed to assess
the clinical value of the thresholds determined.

Langue : ANGLAIS