Modified Exercise Improves Physical Function in Knee Osteoarthritis

Patients with knee osteoarthritis (OA) and severe comorbidities showed significant improvements in physical function after undergoing a tailored exercise program, according to research recently published in Arthritis Care & Research.

“Exercise therapy is a key intervention in the management of knee osteoarthritis,” Mariëtte de Rooij, PhD, from the Amsterdam Rehabilitation Research Center in The Netherlands, and colleagues wrote. “Comorbidity is highly prevalent in knee osteoarthritis and interferes with the application of exercise therapy, contributing to nonadherence. This is the first randomized controlled trial investigating the efficacy and safety of exercise therapy tailored to comorbidity.”

Dr de Rooij and colleagues evaluated 126 patients with OA with comorbidities such as type 2 diabetes, obesity (body mass index ≥30 kg/m²), chronic obstructive pulmonary disease, coronary disease, and heart failure (Cumulative Illness Rating Scale severity score ≥2) who underwent a comorbidity-adapted exercise program. The researchers measured WOMAC (Western Ontario and McMaster Universities Osteoarthritis Index) physical function subscale and 6-minute walk test (6MWT) scores at baseline, after the program (20 weeks), and at 3 months after treatment.

The 20-week program included strength training, training in activities of daily living, and aerobic exercises in the intervention group, while a control group continued to receive their normal care and were placed on a waiting list for exercise therapy. The researchers noted that they provided “additional comorbidity-related education or coaching strategies” during the program and “comorbidity-related symptoms were monitored during each training session, and exercise was adapted if required.”

“Because of an increased risk of comorbidity-related serious adverse events, it was considered unethical to provide regular exercise therapy without tailoring to the comorbid disease,” Dr de Rooij and colleagues wrote. “Thus, the study contrast concerns tailored exercise therapy versus current medical care.”

There were statistically significant improvements in physical function in the exercise groups seen in both WOMAC (−7.43; 95% CI, −9.99 to −4.87; P <.001) and 6MWT scores (34.16; 95% CI, 17.68 to 50.64;

P <.001) compared with the control group, with a 33% improvement in WOMAC score and 15% improvement in 6MWT seen in the exercise group. The researchers reported no adverse events during the study.

“[T]his is the first study showing that tailored exercise therapy is efficacious in improving physical functioning and is safe in patients with knee [osteoarthritis] OA and severe comorbidities,” the investigators concluded. “The results should encourage clinicians to consider exercise therapy as a treatment option for patients with knee OA, even in the presence of comorbidity.”

Study Limitations

The researchers noted the small sample size, inability to measure the effects of tailored exercise on specific comorbidities, and lack of a cost effective analysis of the intervention as limitations in this study.

Disclosures: Haverkamp received grants from Mathys, Implantcast, Arthrex, and Carbylan, and received grants and/or honoraria from Citera and Imove. Dekker received a grant from Merck Sharp & Dohme.

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