Seventy-seven patients were randomized into the following treatment groups: standard of care (no injection), saline injection, hyaluronic acid (HA) or corticosteroid injection (methylprednisolone acetate), whereby injections were conducted using ultrasound guidance. The primary outcome of interest was the numerical rating scale (NRS) score for worst pain. Secondary outcomes of interest included Western Ontario and McMaster Arthritis Index (WOMAC) for pain, and function. As well, the Outcome Measures in Rheumatoid Arthritis Clinical Trials (OMERACT)–OARSI responder was assessed. Outcomes were measured at 1, 4, 8 and 16 weeks post-injection. Results demonstrated a significant improvement in the NRS score for worst pain for the patients in the corticosteroid group over the 8 week period, as well as in the WOMAC scores for pain and function. Furthermore, synovitis was found to be a predictor of steroid response within the corticosteroid treatment arm.