Discontinuation of oral naproxen and initiation of a topical NSAID is the most appropriate therapy for this 75-year-old patient with knee osteoarthritis. The major risks of NSAIDs include gastrointestinal toxicity, cardiovascular disease, hypertension, and kidney disease. Among these, NSAID gastrointestinal risk is higher among older patients and needs to be managed. The American College of Rheumatology currently recommends topical NSAIDs rather than oral NSAIDs for patients aged 75 years or older. A 2012 Cochrane review of topical NSAIDs for chronic musculoskeletal pain included 34 studies with 7688 participants. Topical NSAIDs were superior to placebo for pain relief, with the most data available for topical diclofenac. Topical and oral NSAIDs did not differ with regard to pain relief. Topical NSAIDs led to more skin reactions than placebo or oral NSAIDs and fewer gastrointestinal events than oral NSAIDs.

Discontinuing naproxen and adding celecoxib would reduce the risk of gastrointestinal toxicity to an extent similar to that of adding a proton pump inhibitor (PPI) to naproxen but would be unwarranted in the setting of a good response to topical naproxen. In patients with particularly high risk who require therapy with oral NSAIDs, simultaneously switching to celecoxib and adding a PPI could be considered.

Joint replacement should be considered in patients who have knee osteoarthritis with function and/or pain that cannot be managed using nonsurgical interventions. Because this patient has neither pain nor limitation on his current therapy, consideration of joint replacement would be premature.