Knee Osteoarthritis: The Most Common Pain Medicine is the Least Effective

April 24, 2015 in LifeCare Health Services

Recently, the Annals of Internal Medicine published an expansive research study comparing pain medicine treatments for osteoarthritis (OA) of the knee.(1) The most widely used treatment for knee OA is acetaminophen, better known to us as Tylenol. Interestingly, Tylenol proves to be the least effective pain reliever according to the study. Compared to placebo, Tylenol’s effect was so small that it was considered insignificant.


The study follows 33,243 patients with osteoarthritis of the knee and compares pain medicines taken by mouth. These included over-the-counter medicine such as Tylenol, Ibuprofen, and Aleve, as well as prescriptions like Celebrex and placebo. Placebo means a fake treatment, such as a sugar pill. In controlled trials, placebos are used to create a benchmark of how patients feel without real treatment but with the same amount of time and same level of attention. The study also compares injections of corticosteroids, hyaluronic acid, and placebo. All treatments relieve some knee OA pain after three months, and acetaminophen was the only treatment considered to have insignificant effects.


According to this new study, the most effective pill or injection for pain relief from osteoarthritis of the knee is hyaluronic acid injections. This treatment is an injection of a thick liquid that helps lubricate the knee. After Tylenol, the least effective pain reliever is Celebrex.


While hyaluronic acid injections prove the most effective pain reliever in the short term, four individual studies have found those effects to wear off within six months.(2)  Physical therapy also has proven effectiveness in knee osteoarthritis, and it is often a good idea to use physical therapy in combination with medical treatment. Physical therapy adds long-term pain improvement with an emphasis on flexibility and function. For instance, a study recently published in Osteoarthritis and Cartilage shows that, compared to usual care, physical therapy improves OA of the knee even when measured a year later.(3)


We should note that just because acetaminophen has been found least effective for osteoarthritis of the knee, that does not mean it is not useful elsewhere. Always consult your doctor before deviating from his or her medical advice. However, these results do demonstrate how easy it is for people to waste their time and money while prolonging their discomfort, when an assertive, active approach often offers real solutions. There are multiple effective options for relieving osteoarthritis pain. Adding physical therapy to the treatment plan can create long-term benefit with an emphasis on flexibility and function.


If you are homebound and have suffered a pain flare up or accidental fall, we can send a physical therapist to your home for an effective rehabilitation program to lessen pain, enhance ability, and improve safety.




  1. Bannuru R, Schmid C, Kent D, et al. Comparative effectiveness of pharmacologic interventions for knee osteoarthritis: a systematic review and meta-analysis. Ann Intern Med. 2015; 162 (1): 46-54.
  2. Deyle G, Allison S, Matekel R, et al. Physical therapy treatment effectiveness for osteoarthritis of the knee: a randomized comparison of supervised clinical exercise and manual therapy procedures versus a home exercise program. Physical Therapy. 2005; 85 (12): 1301-17.
  3. Abbott J, Robertson M, Chapple C, et al. Manual therapy, exercise therapy, or both, in addition to usual care, for osteoarthritis of the hip or knee: a randomized controlled trial. 1: clinical effectiveness. Osteoarthritis and Cartilage. 2013; 21: 525-534.

Knee Osteoarthritis Pain Medicine

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