Researchers from the Amsterdam Rehabilitation Research Center studied a combined intervention of analgesics and exercise therapy to determine whether this regimen would allow patients with severe pain from knee osteoarthritis (OA) to participate in exercise therapy, and whether that would lead to a reduction in both their activity limitations and their pain. The study was published in the journal Arthritis Care & Research.

 This is the first study to evaluate a protocol combining standardized analgesic prescription medication and exercise therapy in those with knee OA who experience severe pain.

“Exercise therapy is an effective intervention to reduce pain and activity limitations in patients with knee OA and is therefore recommended in national and international guidelines. However, severe pain hampers the ability to participate in exercise therapy,” wrote Marike van der Leeden, PT, PhD, and colleagues from the Amsterdam Rehabilitation Research Center and VU University Medical Center.

The researchers recruited 49 patients with knee OA and severe knee pain (numerical rating scale for pain ≥7) to examine whether optimizing treatment with analgesics would allow them to participate in exercise therapy and how a combined protocol of analgesic medications and exercise therapy would affect activity limitations and pain.

Analgesics were prescribed following an incremental protocol of acetaminophen, nonsteroidal anti-inflammatory drugs, weak opioid medications, and intra-articular steroid injections. The treatment target was to reduce pain enough to allow patients to participate in exercise therapy. If the participant’s pain score was >5 after treatment with the first analgesic, the person was stepped up to the next analgesic medication.

Nearly all patients (95.5%) received acetaminophen. Of those patients, 32 (76.2%) received the maximum dosage of 3000 mg/day. In total, 18 patients (40.9%) received nonsteroidal anti-inflammatory drugs, 9 of whom received the maximum daily dose of 1000 mg naproxen or 90 mg etoricoxib. Weak opioid medication was administered to 15 patients (34.1%), 8 of whom received the maximal daily dose of 80 mg codeine or 37.5 mg tramadol. Only 2 patients required intraarticular steroid injection.

After 6 weeks of analgesic therapy, a 12-week exercise therapy program was added. Knee pain and activity limitations were assessed at baseline, after 6 weeks, and after 18 weeks.

The researchers found statistically significant improvements in pain and activity limitations after 6 weeks of analgesic use and found further statistically significant improvements when the intervention was completed after 18 weeks. Mean improvements from baseline were 30% (P <.001) for pain and 17% (P <.001) for activity limitations at the end of the study.

“In total, 78% of the patients were able to participate in at least 80% of the exercise therapy sessions according to the protocol,” the researchers wrote. “Patients who could not participate in exercise therapy according to the protocol had significantly more severe radiologic symptoms of osteoarthritis. Surgical interventions need to be considered in this [group] of patients.”

The authors concluded that, although their results were promising, they should be confirmed in a randomized controlled trial.

Summary and Clinical Applicability

Researchers from the Amsterdam Rehabilitation Research Center found that the combined intervention of standardized analgesic therapy and exercise therapy allowed most patients with severe pain from knee OA to participate in exercise therapy and led to statistically significant reductions in their activity limitations and pain.

Reference

van Tunen JA, van der Leeden M, Bos WH, et al. Optimization of analgesics for greater exercise therapy participation among patients with knee osteoarthritis and severe pain: a feasibility study. Arthritis Care Res (Hoboken). 2016;68(3):332-340.