Low- vs High-Dose Exercise Programs Yielded Similar Benefits in Patients with Knee Osteoarthritis

Although high-dose exercise produced similar results in patients with knee osteoarthritis, small benefits were observed regarding knee function in quality of life (QoL) and knee function in sports and recreation in patients in the high-dose exercise cohort, according to a study published in Annals of Internal Medicine.¹

“Knee osteoarthritis is a common disorder that can result in chronic joint pain, knee stiffness, decreased function, reduced QoL, and sick leave,” investigators noted. “Exercise is the preferred treatment and is recommended in treatment guidelines and systematic reviews.”

A multicenter, randomized controlled superiority trial at primary health care facilities in Sweden and Norway evaluated patients with diagnosed knee osteoarthritis and a history of pain and decreased knee function using patient-tailored exercise programs. Patients were assigned to high-dose therapy (11 exercises for 80 to 90 minutes) or low-dose therapy (5 exercises for 20 to 30 minutes) using aerobic, multi-segmental, and joint-specific exercises 3 times a week for 12 weeks (a total of 36 treatments). The individualized exercise therapy was tailored to patients’ specific needs, including functional levels and clinical symptoms using the principles of medical exercise therapy (MET), which was developed in Norway in the 1960s. The Knee Injury and Osteoarthritis Outcome Score (KOOS), a self-reported questionnaire analyzing pain, function in daily living (ADL), function in sports and recreation, and knee-related QoL, was evaluated biweekly during the 3-month intervention period as well as 6 and 12-months post-intervention. The primary outcome was the mean difference (MD) between intervention groups in KOOS.

In total, 189 patients (106 female) were included in the study, with 98 patients assigned to the high-dose cohort and 91 assigned to the low-dose therapy cohort. Although both cohorts improved over time, the high-dose therapy group showed no significant benefits over time. However, the KOOS score for function in sports and recreation was superior in the high-dose therapy group (MD, 8 [95% CI, 2 to 14]; Cohen d = 0.31) at the end of treatment and at 6-months follow-up. Statistically significantly greater improvements in KOOS QoL were also observed at 6- and 12-months post intervention (MD, 8 [CI, 3 to 14]; Cohen d= 0.44; P= 0.004) for those in the high-dose group. Approximately half (47% to 60%) of patients in both groups reported clinically meaningful improvements in all KOOS categories at the end of 12 weeks. Treatment adherence was 98% in the high-dose cohort and 98% in the low-dose cohort.

The study was the first multi-national randomized trial comparing 2 different dosing regimens of exercise therapy in patients with knee osteoarthritis and was able to bind both patient groups as well as the investigators performing statistical evaluations. The high adherence rates also strengthened the study. However, the ceiling effects were present in responder analyses, which may be avoided in future studies. Further, the lack of control group could also be considered a limitation. A lower response rate for follow-up questionnaires was observed and may have influenced results. Lastly, a higher dropout rate was reported in the high-dose group compared with the low-dose group.

“This study adds to the evidence about the effects of exercise dosage on outcomes in knee osteoarthritis and provides novel and important information,” investigators concluded.

Reference:

Torstensen, T. A., Østerås, H., LoMartire, R., Rugelbak, G. M., Grooten, W. J. A., & Äng, B. O. (2023). High- versus low-dose exercise therapy for knee osteoarthritis: A randomized controlled multicenter trial. Annals of Internal Medicine. https://doi.org/10.7326/m22-2348