Variations in the degree of pain relief reported by patients with osteoarthritis following intra-articular corticosteroid injections are well recognized but the reasons for this are not widely understood and factors which might predict variations in response have not been subjected to systematic review. We set out to review systematically the literature relating to predictors of pain reduction following intra-articular corticosteroid injections in patients with knee and hip osteoarthritis.
Searches were performed using Medline, EMBASE, Web of Knowledge and MeSH search of Pubmed, the last search being performed in August 2012. Search terms included knee osteoarthritis, hip osteoarthritis, corticosteroid and related terms, and intra-articular injection. Papers were selected and reviewed by 2 reviewers. For inclusion, papers were required to describe studies in which patients with osteoarthritis of the knee or hip received intra-articular corticosteroid injection as an intervention, contain clearly defined outcome measures relating to pain and contain analysis relating to predictors of clinical response to treatment.
Twenty-one studies met criteria for inclusion from a total of 54 papers reviewed in full. Eight of these related to hip OA and 13 related to knee OA. No factors that were investigated as potential predictors of response, including radiographic grade and clinical or sonographic evidence of inflammation or synovial hypertrophy were supported by strong evidence. The review also identified that several plausible potential predictors had not been studied to date.
Previous research has not identified reliable predictors of response to IA corticosteroid injections, a widely practised intervention in knee and hip OA. Further studies are required if this question is to be answered.