Prevalence and determinants of physical activity and sedentary behaviour before and up to 12 months after total knee replacement : A longitudinal cohort study

Objective:
This study aims to evaluate the prevalence and determinants of inadequate physical activity and excessive sedentary behaviour before and after total knee replacement.
Design, setting and subjects:
Secondary analysis was performed on data from a cohort of 422 adults (45–74 years), drawn from 12 public or private hospitals, undergoing primary unilateral or bilateral total knee replacement surgery.
Main measures:
Questionnaires were used to determine the presence of inadequate physical activity and excessive sedentary behaviour before and 6  and 12 months after total knee replacement surgery. Knee pain, activity limitations, comorbidities, muscle strength, psychological well-being, fatigue, sleep and body mass index were measured/assessed as possible determinants of physical activity or sedentary behaviour.
Results:
Before surgery, 77% (n = 326) of the cohort participated in inadequate physical activity according to World Health Organization guidelines, and 60% (n = 253) engaged in excessive sedentary behaviour. Twelve months after surgery, 53% (n = 185) of the cohort engaged in inadequate physical activity and 45% (n = 157) in excessive sedentary behaviour. Inadequate physical activity before surgery (P = 0.02), obesity (P = 0.07) and comorbidity score >6 (P = 0.04) predicted inadequate physical activity 12 months after surgery. Excessive sedentary behaviour and activity limitations before surgery predicted excessive sedentary behaviour 12 months after surgery.
Conclusion:
Although there were improvements after total knee replacement, 12 months after surgery about half the cohort did not meet World Health Organization recommendations for activity. Pre-surgery assessment of physical activity, activity limitations, sedentary behaviour and body mass index is essential to identify patients at risk for long-term inactivity.