Abstract
Background: Adhesive capsulitis (AC) of the shoulder is an inflammatory condition with pain and limitation in range of motion (ROM) in the glenohumeral joint. The main goal in managing AC is pain reduction and returning the joint function. Intra-articular hyaluronic acid (HA) has recently been considered as a safe modality in AC. However, the clinical properties of HA are associated with its molecular weight. This study aimed to compare the effectiveness of intra-articular injection of low molecular weight (LMW) with high molecular weight (HMW) HA in patients with AC.
Methods: Fifty-six eligible patients with AC were randomized in this triple-blinded clinical trial. All patients underwent standard physical therapy as a baseline care. The follow-up visits were at 4, 12, and 24 weeks after LMW-HA or HMW-HA injection. The primary outcome was the visual analog scale (VAS) and others were the Oxford shoulder score (OSS), active ROM, and patient satisfaction.
Results: No significant differences were detected in between-group variables at baseline. Within-group analysis showed VAS, OSS, and active ROM were markedly improved over time in both groups, also between-group analysis showed VAS and OSS decreased significantly (P<0.001). Four-week follow-up showed the LMW-HA group had lower pain (P= 0.049), conversely, the trend of VAS at 12 weeks and 24 weeks favors HMW-HA (P<0.001). Regarding satisfaction, this parameter had significantly improved in both groups between four-, 12-, and 24 weeks. And there was no significant difference between groups.
Conclusion: HMW-HA is a more effective intervention than LMW-HA in patients with AC.