Clinical Question

In patients with pain and function loss due to knee osteoarthritis, does high-dose medical exercise therapy improve pain and function scores more than low-dose exercise?

Bottom Line

Tailored exercise therapy, at least 20 to 30 minutes three times per week, improves pain and function scores in approximately one-half of patients with painful knee osteoarthritis. For patients interested in sports and recreation, high-dose, longer exercise (70 to 90 minutes) produces better results. (Level of Evidence = 1b−)

Synopsis

The study was conducted in Norway and Sweden, and the researchers enrolled 189 patients, 45 to 85 years of age, with knee osteoarthritis and a history of pain and decreased knee function. The patients did not have previous therapy. Using concealed allocation, the authors assigned participants to 20 to 30 minutes of low-dose exercise therapy (two sets of 10 repetitions) or 70 to 90 minutes of high-dose exercise therapy (three sets of 30 repetitions) that was tailored to their specific needs by a physical therapist. Both groups were given instructions on how to perform the exercises and adjust the weight to perform them without pain. The participants were asked to perform the exercises on their own three times per week for 12 weeks. Both groups improved over time to a similar extent for most outcomes of pain and function using the Knee Injury and Osteoarthritis Outcome Score, with approximately one-half of participants experiencing a clinically meaningful improvement in all outcome categories. High-dose exercise was associated with approximately 20% more participants achieving a clinically important improvement on the Function in Sport and Recreation score, which lasted for three months after the end of the study. The study may have been underpowered to find the minimal clinically important difference between treatments. About 23% of participants dropped out during the study. There may have been a possible placebo response in this unmasked study, and a usual care group as a third comparator may have been helpful.