Knee osteoarthritis (OA) can significantly impact patient QOL through chronic joint pain, knee stiffness, and decreased function. While exercise is recommended for OA treatment, it is unclear what the optimal dose is for exercise therapy.

This randomized clinical trial, published in the Annals of Internal Medicine, compared high-dose and low-dose exercise therapy for patients with knee OA. High-dose therapy was defined as 11 exercises over 70 to 90 minutes. Low-dose therapy was defined as five exercises over 20 to 30 minutes. Patients exercised three times per week for 12 weeks, and then followed up at 6 and 12 months. The primary outcome was the difference in the KOOS, an instrument that measured pain, symptoms, function in daily
living, function in sport and recreation, and knee-related QOL, at 3 months from baseline. The secondary outcome was the Visual Analogue scales (VASs) for pain and the index and VAS from the EuroQoL Group 5-Dimension (EQ-5D) tool for HRQOL.

For the primary outcome, while patients in both groups improved on the KOOS, there were no significant differences between groups.

“The results [of our study] do not support the superiority of high-dose exercise over low-dose exercise for most outcomes,” said lead author Tom Arild Torstensen, MSc, RPT. “Small benefits with high-dose exercise were found for knee function in sports and recreation and for QOL.”

One exception, according to Torstensen, was the KOOS score for function in sports and recreation. In this case, “high-dose therapy was superior at the end of treatment and at the 6-month follow-up,” he said, adding that a small benefit in QOL at 6 and 12 months was also noted.

No significant differences were found for the VASs and EQ-5D scores at any of the follow-ups. As a limitation, there was no control group and therefore, the true benefit of exercise therapy was unable to be assessed.

In-DEPTH (Randomized Controlled Trial)

This randomized controlled clinical trial assessed the efficacy of high-dose versus low-dose exercise therapy for improving QOL and symptoms in patients with knee OA. A total of 189 patients aged 45-85 with knee OA and a history of knee pain with decreased function were randomized to receive either high-dose (N=98) or low-dose (N=91) exercise therapy. For the primary outcome, there were no significant differences between groups in the KOOS at any point of follow-up. However, the KOOS sport and recreation subscale score was significantly higher in the high-dose therapy group compared with the low-dose therapy group at the end of the intervention (Mean Difference [MD], 8; 95% CI, 2-14) and at 6 months after intervention (MD, 11; 95% CI, 4-17). The significant difference was not sustained at 12 months’ follow-up. For the secondary outcome, there were no differences in mean score for the pain intensity (VAS) score or QOL (EQ-5D) scores.

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