Objective. Arthritis of the knee affects 46 million Americans. We aimed to determine the level of evidence of intraarticular knee injections in the management of arthritic knee pain.
Methods. We systematically searched PUBMED/MEDLINE and the Cochrane databases for articles published on knee injections and evaluated their level of evidence and recommendations according to established criteria.
Results. The evidence supports the use of intraarticular corticosteroid injections for rheumatoid arthritis (1A+ Level), osteoarthritis (1A+ Level), and juvenile idiopathic arthritis (2C+ Level). Pain relief and functional improvement are significant for months up to 1 year after the injection. Triamcinolone hexacetonide offers an advantage over triamcinolone acetonide and should be the intraarticular steroid of choice (2B+ Level). Intraarticular injection of hyaluronate may provide longer pain relief than steroid injection in osteoarthritis (2B+ Level). It can also be effective for rheumatoid arthritis knee pain (1A+ Level). However, it is only recommended for patients with significant surgical risk factors and for patients with mild radiographic disease in whom conservative treatment has failed (2B± Level). Botulinum toxin type A injection is effective in reducing arthritic knee pain (2B+ Level), and so is tropisetron (2B+ Level) and tanezumab (2B+ Level). The new agents, such as rAAV2-TNFR:Fc, SB-210396/CE 9.1, and various radioisotopes have provided various degrees of success, but their long-term safety and efficacy remains to be determined.
Conclusions. We conclude that strong evidence supports the use of intraarticular knee injection as a valuable intervention in the continuum of management of arthritis between conservative treatment and knee surgeries.