Applied Evidence

A practical approach to knee OA

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HA is found naturally in articular cartilage, which explains the rationale behind its use. A network meta-analysis performed by the American Medical Society for Sports Medicine concluded that knee OA is more likely to respond to IAHA than to IACS or IA placebo, leading the society to recommend the use of IAHA in knee OA management, especially for patients > 60 years with mild-to-moderate knee OA.9 Conversely, the AAOS does not recommend the use of IAHA, and the ACR does not recommend for or against the use of IAHA.10,41

Platelet-rich plasma therapy is expensive and generally is not covered by insurance companies, which precludes its use for many people.

IACSs are commonly used to provide pain relief in those with moderate-to-severe knee OA. There is evidence that a single IACS injection provides mild pain relief for up to 6 weeks.49 However, there is some concern that repetitive IACS injections may speed cartilage loss. A 2-year randomized double-blind placebo-controlled trial comparing the effectiveness of repetitive IA triamcinolone vs saline in knee OA found no difference in pain severity and concluded that there was greater cartilage volume loss in the triamcinolone group.50

AAOS does not recommend for or against the use of IACSs, whereas the ACR does recommend for the use of IACSs.10,41 Given the available evidence, conservative use of IACS injections remains an option for patients with refractory moderate-to-severe knee OA.


Topical analgesics are often utilized for knee OA because of their efficacy, tolerability, low risk of adverse effects, and ease of use. They are generally recommended over oral NSAIDs in the elderly and in individuals at risk for cardiac, renal, and gastrointestinal complications from oral NSAIDs.

Extendedrelease IA triamcinolone acetonide (Zilretta) has shown some superiority to standard IA triamcinolone acetonide in both degree and duration of pain relief for knee OA.

One review found that topical diclofenac and topical ketoprofen were comparable to the oral forms of these medications.51 One RCT concluded that topical and oral diclofenac were equally efficacious in treating knee OA symptoms, although topical diclofenac was associated with significantly fewer gastrointestinal adverse effects.52 In multiple randomized trials, topical diclofenac has shown efficacy compared to placebo.53-55 A recent systematic review and meta-analysis of RCTs concluded that topical NSAIDs were safe and effective for treating general OA compared to placebo, with diclofenac patches most effective for pain relief and piroxicam most effective for functional improvement.56

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