BOSTON — Exercises that simulate the mechanically challenging activities of daily living lessen energy expenditures and compensations associated with knee osteoarthritis, Dr. Anthony M. Reginato said at the 10th World Congress on Osteoarthritis.
As such, functional interventions should be an important component of rehabilitation therapy, he said at the congress, which was sponsored by the Osteoarthritis Research Society International.
In a double-blind, randomized trial, Dr. Reginato and his colleagues at Massachusetts General Hospital in Boston analyzed chair rise and box lifting in patients with knee osteoarthritis to determine if functional training or strengthening exercises led to improvements in mechanical energy expenditures (MEE), mechanical energy compensations (MEC), linear and angular momentum, and/or performance duration.
The study included 26 individuals, aged 43–86 years, who had Kellgren-Lawrence grade 2 or 3 knee osteoarthritis and at least two functional limitations on the SF36 physical functioning subscale. Participants were randomized to receive 8 weeks of physical therapy comprising either strength training or functional training.
“The goal of strength training is to address specific impairments, including range of motion and the ability to generate muscle force,” Dr. Reginato said.
In contrast, functional training simulates activities of daily living, such as gait, rising from a chair, and stair climbing, at different speeds and levels of difficulty, the goal of which is to improve neuromuscular control of the whole body, with specific focus on the individual's abilities and safety limits, he explained.
At baseline and postintervention, each participant completed a chair rise test, which required arising from a backless chair, and a box lift test, which required hoisting a plastic case holding a 5-kg metal disk onto a table. During both tasks, investigators calculated ankle, knee, hip, and back MEE and MEC. They also assessed maximum whole body angular momentum, maximum whole body anterior posterior linear momentum, and maximum whole body vertical linear momentum, as well as the intervals between the start and end of each task.
Using univariate analysis of covariance and multivariate analysis of variance to compare between-group differences in score changes relative to baseline, the investigators determined that, in the chair rise, the functional training group had significantly more improvement in energy expenditures and compensations by increasing ankle energy expenditure and decreasing back compensation, compared with the strength training group. And while there were no significant differences in chair rise interval times between the groups, the functional training group had a greater change from baseline in this measure.
In the box lift test, both groups increased their MEE in the back during the “no transfer” phase of lifting, although the strength training group had significantly higher changes in this measure, Dr. Reginato reported. In the transfer phase, the strengthening group had a significantly greater change in MEE in the back, compared with the functional group, which showed a decrease in this measure, and greater change in maximum whole body angular momentum.
The findings suggest that both functional and impairment-level interventions have important roles in the treatment of knee osteoarthritis, he said.