A comprehensive review of over 200 studies has determined that aerobic exercises such as walking, cycling, and swimming provide the most effective pain relief and mobility improvements for people with knee osteoarthritis. Published in The BMJ, the analysis emphasizes aerobic activity as the foundation of treatment. All tested exercise types proved safe, with no increased adverse events compared to controls.
Knee osteoarthritis, which affects about 30% of adults over age 45 on x-rays and causes significant pain and mobility issues in half of those cases, occurs when cartilage cushioning bone ends wears down, leading to swelling, stiffness, and discomfort. Exercise serves as a cornerstone of care, but guidelines have lacked specificity on optimal types for knees.
To address this, researchers conducted a systematic review and network meta-analysis of 217 randomized clinical trials from 1990 to 2024, involving 15,684 participants. They compared aerobic, flexibility, strengthening, mind-body, neuromotor, and mixed exercise programs against controls, evaluating outcomes like pain, physical function, gait performance, and quality of life at short-term (four weeks), mid-term (12 weeks), and long-term (24 weeks) follow-ups using the GRADE system for evidence strength.
Aerobic exercise ranked highest across categories. Moderate-certainty evidence showed it reduced pain in the short and mid-term and improved function in the short and long term, while also enhancing gait performance and quality of life in the short and mid-term. Other forms offered benefits too: mind-body exercises likely improved short-term function, neuromotor exercises boosted short-term gait, and strengthening or mixed routines aided mid-term function.
The study, led by researchers including Lei Yan and Yihe Hu, notes limitations such as indirect comparisons, limited long-term data for some outcomes, and potential influence from smaller studies. Nonetheless, the authors recommend aerobic exercise "as a first line intervention for knee osteoarthritis management, particularly when the aim is to improve functional capacity and reduce pain." If aerobic activity is not feasible due to individual limitations, they advise that "alternative forms of structured physical activity may still be beneficial."
This evaluation, described as one of the most complete and current, aims to guide clinicians toward more targeted recommendations.