Recurrence of the frozen shoulder after hydrodilatation, what is the true incidence?

Purpose of the study: To assess the outcome and recurrence rates of frozen shoulder treated by hydrodilatation in an independent hospital setting. Method: Patients presenting to a shoulder clinic from August 2019 to July 2021 with a diagnosis of frozen shoulder were offered hydrodilatation. Data included primary or secondary frozen shoulder, length of symptoms, and diabetic status. An Oxford Shoulder Score was completed prior to hydrodilatation. Using ultrasound guidance, 40 mg Triamcinolone and local anaesthetic (10-25 mL depending on patient tolerance) were injected into the rotator interval. At a mean of 9 months, patients recorded their tolerance of the procedure, subsequent progress, the need for further treatment, and their current Oxford Shoulder Score. Results: From 55 shoulders, six patients had a failure to improve and 10 patients had a transient improvement followed by recurrence (29%). 2/21 (9.5%) patients had 25 mL injected compared to 14/34 (41%) who had < = 20 mL (p = 0.012). 14/43 (33%) of primary frozen shoulder patients had a recurrence, compared with 2/12 (16%) secondary frozen shoulder patients, p = 0.019. Conclusion: Further treatment was indicated in 14/34 (41%) of patients who underwent hydrodilatation in the frozen stage of frozen shoulder and could not tolerate more than 20 mL of injection, and was more commonly required in primary (33%) versus secondary (16%) frozen shoulder.