Outcomes of hyaluronic acid injections for glenohumeral osteoarthritis: a systematic review and meta-analysis

BACKGROUND: Hyaluronic acid (HA) is an analgesic and chondroprotective agent often used for the nonoperative treatment of osteoarthritis (OA). The effects of HA injections are well studied in the treatment of knee OA, but the effects in glenohumeral OA remain unclear. This study evaluated the efficacy of HA to reduce pain in patients with glenohumeral OA. METHODS: PubMed, MEDLINE, CENTRAL, and Embase were searched from the database inception date through January 16, 2018. Two reviewers independently screened articles for eligibility and extracted data for analysis. A methodological quality assessment was completed for all included studies, including assessment of risk of bias. The primary outcome was change in visual analog scale for pain. The secondary outcomes were functional outcome and adverse events. RESULTS: In the HA arm, the reduction of visual analog scale pain score at 3 months was 26.2 mm (95% confidence interval, 22.0-30.3 mm; I² = 31%) and at 6 months was 29.5 mm (95% confidence interval, 25.5-33.4 mm; I² = 19%). All studies reported an improvement in functional outcome. Similar clinical improvements were reported in the intervention and control groups, suggesting that these improvements may not be directly related to HA. Commonly reported adverse events were rare and included swelling and mild pain at the injection site, local effusion, lethargy, and face rash. CONCLUSION: Intra-articular HA injection is safe and improves pain for patients with glenohumeral OA. Pain improvements also reported in the control group suggest that a significant placebo effect may be present with respect to intra-articular shoulder injection. Further randomized controlled trials are necessary to evaluate the efficacy of HA and identify optimal dosing and route of administration.