Applied Evidence

A practical approach to knee OA

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Pharmacotherapy: Oral agents

Acetaminophen. Although people commonly use this over-the-counter analgesic for knee OA pain, recent meta-analyses have shown that acetaminophen provides little to no benefit.36,37 Furthermore, although many believe acetaminophen causes fewer adverse effects than oral nonsteroidal anti-inflammatory drugs (NSAIDs), liver, gastrointestinal, and renal complications are not uncommon with long-term acetaminophen use. Nevertheless, a trial of acetaminophen may be beneficial in patients with cardiovascular disease or who are taking oral anticoagulants.

Oral NSAIDs. Many studies have concluded that NSAIDs are more effective at controlling pain from knee OA than acetaminophen.37,38 They are among the most commonly prescribed treatments for knee OA, but patients and their physicians should be cautious about long-term use because of potential cardiac, renal, gastrointestinal, and other adverse effects. Although evidence regarding optimal frequency of use is scarce, oral NSAIDs should be used intermittently and at the minimal effective dose in order to decrease the risk of adverse events.

One recent meta-analysis of RCTs concluded that diclofenac at a dose of 150 mg/d is the most effective NSAID for improving pain and function associated with knee OA.37 Another recent systematic review and meta-analysis analyzing multiple pharmacologic treatments found an association between celecoxib and decreased pain from knee OA.39 However, this study also concluded that uncertainty surrounded all of the estimates of effect size for change in pain compared to placebo for all of the pharmacologic treatments included in the study.39

A meta-analysis of RCTs comparing celecoxib to no treatment, placebo, naproxen, and diclofenac concluded that celecoxib is slightly better than placebo and the aforementioned NSAIDs in reducing pain and improving function in general OA. However, the authors had reservations regarding pharmaceutical industry involvement in the studies and overall limited data.40

With all of that said, the American Academy of Orthopaedic Surgeons (AAOS) recommends strongly for the use of oral NSAIDs in the management of knee OA.41

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