Exercise helps patients with knee osteoarthritis (OA), but more isn’t necessarily better, new research shows.
A low-dose exercise regimen helped patients with knee OA about as much as a more intense workout plan, according to trial results published online January 23 in Annals of Internal Medicine.
Both high and low doses of exercise reduced pain and improved function and quality of life.
The improvements with the lower-dose plan and its 98% adherence rate are encouraging, said Nick Trasolini, MD, assistant professor of orthopedic surgery at Atrium Health Wake Forest Baptist Medical Center, Winston-Salem, North Carolina.
“This is a very doable amount of medical exercise therapy for patients with knee osteoarthritis, and one that makes a big difference in patient-reported symptoms,” Trasolini, who was not involved in the study, told Medscape Medical News.
What’s the Right Dose?
Exercise is a go-to treatment for knee OA, but the precise dose to recommend has been unclear. To study this question, Tom Arild Torstensen, MSc, RPT, with Karolinska Institutet, Huddinge, Sweden, and Holten Institute, Stockholm, Sweden, and his colleagues conducted a trial at four centers in Sweden and Norway.
The study included 189 men and women with knee OA. Participants were randomly assigned to low- or high-dose exercise plans, which they performed three times per week for 12 weeks under the supervision of a physiotherapist.
Participants in the high-dose group performed 11 exercises during each session, which lasted 70–90 minutes.
The low-dose regimen consisted of five exercises ― cycling, squats, step-ups, step-downs, and knee extensions ― performed for 20–30 minutes.
The researchers measured outcomes using the Knee Injury and Osteoarthritis Outcome Score (KOOS), which assesses pain, other symptoms, function in daily living, function in sports and recreation, and knee-related quality of life.
“Patients in both groups improved significantly over time, but high-dose exercise was not superior to low-dose exercise in most comparisons,” Torstensen and his co-authors report.
High-dose exercise was associated with better function in sports and recreational activity and knee-related quality of life at 6 months. Those differences did not persist at 1 year, however. The researchers report no safety concerns with either intervention.
Adherence was “nearly perfect” in the low-dose group. It was slightly lower in the high-dose group, the researchers say.
“Interestingly, it seems that high-dose treatment could be preferable to low-dose treatment in the long run for people who lead active lives,” they write. “This should be the subject of future studies.”
All clinical practice guidelines for knee OA recommend exercise, but “we do not know the optimal dose,” Kim Bennell, PhD, a research physiotherapist at the University of Melbourne, Australia, told Medscape.
Dose has components, including number of times per week, number of exercises, sets and repetitions, intensity, and duration of exercise sessions, Bennell said.
“These results suggest that an exercise program that involves less time and fewer exercises can still offer benefits and may be easier for patients to undertake and stick at than one that involves greater time and effort,” she said.
The study was supported by the Swedish Rheumatic Fund. Trasolini and Bennell have disclosed no relevant financial relationships.
Ann Intern Med. Published online January 23, 2023. Abstract