Letter to Editor - Keith K W Chan

(Medical Progress October, 2009)

Dear Editor,

I read with interest the article by Rediet Kokebie and Joel A. Block on “Managing Osteoarthritis: Current and Future Directions”1.  While the article provides readers a comprehensive review of the topic, the authors, being rheumatologists, are biased towards the role of NSAIDs on osteoarthritis (OA) therapy.

For decades, there has not been a consensus on whether acetaminophen or NSAIDs should be used as first-line agent to treat knee OA2-3.  Currently, many international guidelines still advocate the use of acetaminophen as the first-line medication for OA knee patients with mild to moderate pain4-7.

One reason for this ongoing debate, as rightly pointed out by the authors, is not only that “OA is more than a degenerative disease of the cartilage but also that biomechanics play a critical role in disease onset and progression”.  In fact, the pain experienced by most OA patients is a mechanical pain that occurred during motion or joint loading.  In a recent survey conducted in Hong Kong, 95% of OA knee patients do not have signs of inflammation at the time of screening by physicians8

Furthermore, co-morbidities among OA knee patients are very common.  According to the same Hong Kong study, among the OA knee patients presented to primary care clinics, 33% and 29% of them have co-existing cardiovascular and gastrointestinal diseases respectively8.  From the literature, a meta-analysis of 138 studies demonstrated that selective COX-2 inhibitors and high dosages of ibuprofen and diclofenac were associated with increased risk of vascular events9.  Another meta-analysis concluded that NSAIDs but not acetaminophen increased the risk of upper gastrointestinal bleeding10.  Therefore I would have to disagree with the statement made by the authors that “despite safety concerns and recent publicity about cardiovascular risks, NSAIDs and cyclo-oxygenase (COX)-2 inhibitors remain the mainstay of OA therapy”.

As the majority of OA knee patients have only mild to moderate symptoms, I would recommend physicians to use acetaminophen as the first-line medication for OA knee patients especially when their pain most of the time is mechanical in nature.  I certainly would not object the use of NSAIDs or COX-2 inhibitors to alleviate those inflammatory pain during flares but only on short-term basis.


Dr Keith KW Chan
President, Hong Kong Institute of Musculoskeletal Medicine



  1. Kokebie R, Block JA. Managing osteoarthritis: Current and future directions. Medical Progress 2009;36:409-416.
  2. Moskowitz RW. Osteoarthritis: simple analgesic versus nonsteroidal antiinflammatory drugs. J Rheumatol 2001;28(5):932-934.
  3. Brandt KD, Bradley JD. Should the initial drug be used to treat osteoarthritis pain be a nonsteroidal antiinflammatory drug. J Rheumatol 2001;28(3):467-473.
  4. Jordan KM, Arden NK, Doherty M, et al. EULAR Recommendations 2003: an evidence based approach to the management of knee osteoarthritis: Report of a Task Force of the Standing Committee for International Clinical Studies Including Therapeutic Trials (ESCISIT). Ann Rheum Dis 2003;62:1145-1155.
  5. American College of Rheumatology Subcommittee on Osteoarthritis Guidelines. Recommendations for the medical management of osteoarthritis of the hip and knee. Arthritis and Rheumatism 2000;43:1905-1915.
  6. Schnitzer TJ. Update on guidelines for the treatment of chronic musculoskeletal pain. Clin Rheumatol 2006;25(suppl 1):S22-S29.
  7. National Institute for Health and Clinical Excellence. NICE clinical guideline 59. Osteoarthritis: the care and management of osteoarthritis in adults. Available at:http://www.nice.org.uk/nicemedia/pdf/CG59NICEguideline.pdf. Accessed on 4 June 2009.
  8. Chan KW, Ngai HY, Ip KK, et al. Co-morbidities of patients with knee osteoarthritis. Hong Kong Med J 2009;15:31-38.
  9. Kearney PM, Baigent C, Godwin J, et al. Do selective cyclo-oxygenese-2 inhibitirs and traditional non-steroidal anti-inflammatory drugs increase the risk of atherothrombosis? Meta-analysis of randomized trials. BMJ 2006;332:1302-1308.
  10. Lewis SC, Langman MJS, Laporte J, et al. Dose-response relationship between individual nonaspirin nonsteroidal anti-inflammatory drugs (NANSAIDs) and serious upper gastrointestinal bleeding: a meta-analysis based on individual patient data. Br J Clin Pharmacol 2002;54:320-326.