DENVER – Initiating exercise therapy early on in people who develop symptoms of knee osteoarthritis – even within their first year of pain or reduced function – is associated with modestly lower pain scores and modestly better function than in those whose symptoms have lasted longer, according to a study presented at the OARSI 2023 World Congress.
Although the benefits of exercise therapy for advanced knee osteoarthritis had already been well established, this study looked specifically at benefits from exercise therapy earlier on, in patients with a shorter duration of symptoms.
“Exercise indeed seems especially beneficial in patients with shorter symptom duration and should therefore be encouraged at first symptom presentation,” Marienke van Middelkoop, PhD, of Erasmus MC Medical University in Rotterdam, the Netherlands, told attendees at the meeting, sponsored by Osteoarthritis Research Society International. “It is, however, still a challenge how we can identify patients but also how we can motivate these patients with early symptoms of osteoarthritis.” She noted that a separate pilot study had experienced difficulty recruiting people with short-term symptom duration.
The researchers compared the effect of exercise therapy and no exercise among adults at least 45 years old with knee osteoarthritis, relying on individual participant data from the STEER OA study, a meta-analysis of 31 studies that involved 4,241 participants. After excluding studies that didn’t report symptom duration, lacked a control group or consent, or focused on hip osteoarthritis, the researchers ended up with 10 studies involving 1,895 participants. These participants were stratified based on the duration of their symptoms: up to 1 year (14.4%), 1-2 years (11%), and 2 years or longer (74%).
About two-thirds of the participants were women (65.9%), with an average age of 65 years and an average body mass index (BMI) of 30.7 kg/m2. Any land-based or water-based therapeutic exercise counted for the 62% of participants in the intervention group, while the control group had no exercise. Outcomes were assessed based on self-reported pain or physical function at short-term and long-term follow-up, which were as close as possible to 3 months for short-term and the closest date to 12 months for longer term. At baseline, the participants reported an average pain score of 41.7 on a 0-to-100 scale and an average physical function score of 37.4 on a 0-to-100 scale where lower scores indicate better function.
Among those doing exercise therapy, average pain scores dropped 4.56 points in the short term and 7.43 points in the long term. Short-term and long-term pain scores were lower among those whose symptom durations were shorter. For example, those with symptoms for less than a year reported a short-term pain score of 29, compared with 30 for those with 1-2 years of pain and 32 for those with at least 2 years of pain. Results were similar for long-term pain (a score of 26, compared with 28 and 33, respectively).
Participants engaging in exercise therapy also improved average function scores, with a pattern of improvement that was similar to pain scores based on patients’ symptom duration. The average short-term function score was 26 among those with less than a year of symptoms, compared with 28 for those with symptoms for 1-2 years, and 30 for those with symptoms for at least 2 years. Longer-term function scores were 21, 24, and 29, respectively, based on increasing symptom durations.
Chris Yun Lane, PT, DPT, a physical therapist and a fourth-year PhD student at the University of North Carolina at Chapel Hill, was not surprised at the exercise benefit given the extensive evidence already showing that exercise is beneficial for patients with osteoarthritis whose symptoms have lasted longer.
“Just spending a little bit of time on education, designing kind of simple exercise programs, such as walking programs, can be very helpful,” Dr. Lane said in an interview. “Of course, some of it is dependent on the patient itself, but strengthening range of motion is often very helpful.” Dr. Lane said it’s particularly important for physicians and physical therapists to emphasize the importance of exercise to their patients because that guidance doesn’t always occur as often as it should.
Ron Ellis Jr., DO, MBA, chief strategy officer of Pacira BioSciences in Tampa, Fla., noted that a lot of patients with knee osteoarthritis have weakness in their quads, so quad strengthening is “a typical part of our improvement program for patients with osteoarthritis,” he said in an interview. Dr. Ellis also referenced a session he attended the previous day that showed exercise results in reduced inflammation.
“So you may not have weight loss, but you can lower the inflammatory state of the overall body and of the specific joints,” Dr. Ellis said, “so that would support [this study’s] conclusion.”
The STEER OA study was funded by the Chartered Society of Physiotherapy Charitable Trust and the National Institute for Health Research School of Primary Care Research. Dr. van Middelkoop and Dr. Lane both reported having no relevant financial relationships.