Associação entre intensidade do eco e o desempenho físico funcional de mulheres idosas com osteoartrite de joelho

Abstract

Aging and knee osteoarthritis are associated with declines in muscle quality that may compromise physical functional performance. Echo intensity obtained from B-mode ultrasound has been used as a noninvasive marker of muscle quality, although its relationship with physical function in older women with knee osteoarthritis remains poorly understood. This study investigated the association between muscle quality of the knee extensors and ankle plantarflexor and dorsiflexor muscles with functional physical performance in older women with and without knee OA. A total of 41 older women participated (16 with OA and 25 without OA). Muscle quality was assessed using corrected EI, and functional performance was evaluated through the Timed Up and Go test and 6-meter gait speed test, both analyzed using an inertial measurement unit. Statistical analyses included Shapiro–Wilk tests, Student’s t-test or Welch’s test, Mann–Whitney U test, Pearson or Spearman correlations, and multiple linear regression. All analyses were conducted in R 4.1.1. Between-group comparisons revealed no significant differences in muscle quality (p > 0.05) or functional performance (p > 0.05), although the OA group showed numerically higher EI values and slightly lower functional performance. Correlation analyses did not identify statistically significant associations between muscle quality and functional performance in either group. Similarly, predictive models demonstrated low explanatory power (adjusted R² ranging from –0.02 to 0.17), indicating that functional variables, age, and OA status did not consistently predict muscle quality within this sample. In conclusion, although prior literature highlights potential interactions between muscle degeneration and functional performance in older adults, the current findings did not reveal robust associations between muscle quality and physical function, nor significant differences between women with and without knee OA. Larger and longitudinal studies are warranted to further understand these relationships.