Intra-articular injection of hyaluronic acid (HA) is a common, yet controversial therapeutic option in treating knee osteoarthritis (OA). The purpose of the present study was to assess the risk of bias (RoB) of systematic reviews (SRs) and to summarize available evidence of HA in treating knee OA.
A systematic search of SRs published through to December 2016 was conducted using the MEDLINE, EMBASE and Cochrane Library. The RoB of included SRs was assessed by ROBIS tool. In addition, the methodological quality of primary studies in SRs with low RoB was evaluated according to the Cochrane Handbook. The evidence quality of each primary outcome of SRs with low RoB was determined by the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) system.
Thirty-one SRs were eligible for inclusion. According to the ROBIS tool, there were 13 SRs with low RoB, 16 with high RoB and two with unclear RoB. The methodological quality of a total of 135 primary studies was evaluated and summarized. Forty-two outcomes from these 13 SRs were classified into the four following quality levels based on the GRADE approach: three outcomes with high quality, eight with moderate quality, 12 with low quality and 19 with very low quality.
This study evaluated RoB in SRs for managing knee OA with HA and assessed the evidence quality of each primary outcome in SRs with low RoB. These results can help users of SRs to improve the process of SR assessment in developing overviews or guidelines, leading to more reliable recommendations for improvements in treating knee OA. Registration: PROSPERO ((http://www.crd.york.ac.uk/PROSPERO) [CRD42017057384].