Subacromial impingement syndrome: a prospective comparison of ultrasound-guided versus unguided injection techniques

Objectives: To evaluate the hypothesis that ultrasound-guided subacromial steroid injection produces greater reduction in morbidity than unguided injection. Design: All patients underwent either ultrasound-guided subacromial injection with 80 mg Depo-Medrone at Bradford Royal Infirmary (group 1) or unguided injection (group 2) by a general practitioner with a specialist interest in musculoskeletal medicine (GPwSI). Patients were clinically and ultrasonically diagnosed with subacromial impingement syndrome. Setting: Patients in group 1 included both hospital and GP referrals. Patient in group 2 were GP referrals to GPwSI. Main outcome measures: Comparison was made of pre-injection and six week post-injection Oxford shoulder score and a 0-10 pain score. Results: Forty-one patients received guided injections (group 1) and 17 unguided (group 2). Group 1 showed a significant mean reduction in the Oxford shoulder score of 9.10 (95% CI 7.07-11.13, P< 0.0001) and a significant change in the mean 0-10 pain score of 23.26 (95% CI 22.51 to 23.88, P<0.0001). Group 2 also showed significant reduction in the mean Oxford shoulder score of 9.94 (95% CI 6.41-13.47, P<0.0001) and significant change in the mean 0-10 pain score of 22.94 (21.95 to 23.93, P< 0.0001). Comparison of groups 1 and 2 for each outcome measure revealed no significant differences. Conclusion: Our data confirm the efficacy of steroid injection in the management of subacromial impingement, although no significant difference is found when comparing the two groups. We recommend the continued use of unguided injections, with ultrasound used for more practically difficult cases and where there is diagnostic uncertainty.