Methotrexate for Knee OA?
Maybe—but only if larger, longer-term studies replicate the findings from a randomized trial of 144 patients (mean age = 66 years) published recently in the Annals of the Rheumatic Diseases.
Subjects with knee osteoarthritis (OA) in the double-blind Annals study received either placebo or up to 25 mg per week of oral methotrexate over a 28-week period. At 28 weeks, researchers found greater reductions in knee pain and larger improvements in scores of physical function and activities of daily living in the methotrexate group than in the placebo group. The authors also noted a significantly greater reduction in synovitis, measured both clinically and with ultrasound, in the methotrexate group relative to the placebo group.
Methotrexate is a powerful drug prescribed to treat certain cancers and refractory rheumatoid arthritis, but it has many well-known and potentially serious side effects, such as hematopoietic suppression and liver toxicity. Nevertheless, these authors reported few adverse events; those that did occur included self-limiting mucositis, alopecia, GI disturbance, and transaminitis.
While some people are thought to have a more inflammatory phenotype of osteoarthritis than others, this study did not stratify patients along inflammatory lines, so further research will be needed to determine whether methotrexate’s clinical benefits accrue equally to OA patients generally, or mostly to those with the inflammatory subtype.