OBJECTIVES: Knee osteoarthritis (KOA) is a chronic disease that causes pain and worsens not only articular function, but also the patient's quality of life (QoL). Collagen for intra-articular injection (IAI), such as atelocollagen and polymerized collagen, features low immunogenicity. Previous studies reported that it could help improve symptoms of KOA. The aim of this systematic review was to evaluate the effectiveness and safety of IAI using collagen in KOA with Kellgren-Lawrence grade 1~3.

METHODS: We searched Ovid-MEDLINE, Ovid-EMBASE, Cochrane library and five Korean databases on 26 November 2020. The risk of bias was assessed by Scottish Intercollegiate Guidelines Network methodology checklist.

RESULTS: Of the total 373 articles retrieved, five RCT articles were selected. Two articles were compared with hyaluronic acid (HA) and three were compared with sham control. There was no significant difference observed between the collagen and hyaluronic acid groups in terms of the degree of pain improvement measured by VAS and the usage of analgesics. Articular function, assessed by Lequesne knee index (LKI) and international knee documentation committee (IKDC), showed no significant differences in both groups. Three studies compared collagen with sham control using polyvinyl-pyrrolidone (PVP) or normal saline. In two out of the three studies, significant reductions in pain and improvements in articular function were reported in the collagen group compared to the PVP group. Among the five articles reporting QoL and patient satisfaction, one study reported significantly higher satisfaction with collagen compared to normal saline, and two studies reported more positive results with collagen than PVP. All studies reported pain lasting less than 24 hours and only mild adverse events.

CONCLUSIONS: The evidence showed that intra-articular injection (IAI) using collagen is safe and effective for relieving pain and improving articular function in KOA with Kellgren-Lawrence grade 1~3.