What volume of injection should be used in hydrodilatation for frozen shoulder? A prospective cohort study.

This study evaluated the outcome and recurrence rates after hydrodilatation (HD) in patients with frozen shoulder (FS), comparing the effects of injecting 25 mL or more of fluid versus lower volumes. A total of 132 shoulders (130 patients) were treated at a shoulder clinic between August 2019 and February 2023. HD was performed under ultrasound guidance, injecting a combination of 40 mg Triamcinolone, 10 mL of local anaesthetic, and saline to a total volume of 10 to 40 mL based on patient tolerance. The results were analysed based on the volume of fluid injected and whether patients were diabetic. The overall failure or recurrence rate (FRR) was 24% after a minimum of 1 year. Non-diabetic patients injected with ≥25 mL had a significantly lower FRR (9%) compared to those injected with <25 mL (30%, p = 0.006). Diabetic patients had a much higher FRR of 52%, compared to 17% in non-diabetics (p = 0.0002). The study concluded that injecting patients with ≥25 mL of fluid had a significantly lower FRR than those injected with <25 mL at a minimum of 12 months follow-up (9% vs 30%, p = 0.006). Diabetic patients experienced a higher rate of recurrence, suggesting the need for patient counselling about the increased likelihood of failure.