Predictive value of subacromial motion metrics for the effectiveness of ultrasound-guided dual-target injection: a longitudinal follow-up cohort trial.

OBJECTIVE

Subacromial impingement syndrome (SIS) frequently causes shoulder pain. This study aimed to (1) assess the predictive utility of quantitative dynamic subacromial ultrasound for ultrasound-guided dual-target injections and (2) compare the long-term efficacy of dual-target injections with standard subdeltoid-subacromial injections in SIS patients.

METHODS

Patients with SIS received 40 mg of triamcinolone acetonide via ultrasound-guided dual-target injections (subdeltoid-subacromial bursa and long head of the biceps brachii tendon). Clinical assessments and static/dynamic ultrasound were performed at baseline and 4 weeks post-procedure. Minimal vertical acromiohumeral distance (mVAHD) was measured by tracing the humeral greater tuberosity against the acromion. A historical cohort receiving standard subdeltoid-subacromial corticosteroid injections was used for comparison.

RESULTS

Of 90 patients receiving dual-target injections, 70 (77.7%) achieved early treatment success. An enlarged minimal mVAHD was associated with success, except during the abduction phase in the full-can posture. Among these 70 patients, 25 (35.7%) had shoulder pain recurrence requiring repeat injections, linked to a decreased mVAHD across all phases and postures. Compared to 90 patients in a historical cohort receiving standard subdeltoid-subacromial injections, the dual-target group had a significantly longer mean time to pain recurrence (309.1 ± 130.1 days vs. 267.5 ± 184.2 days, p = 0.03).

CONCLUSION

Dynamic ultrasound metrics, including mVAHD, predict early success and pain recurrence following dual-target injections in SIS. Dual-target injections offer a longer duration of effectiveness compared to standard subdeltoid-subacromial injections. Future research should explore the predictive value of mVAHD with deep learning algorithms and evaluate the approach in adhesive capsulitis.

TRIAL REGISTRATION

ClinicalTrials.gov (NCT04219527). Registered on 27 December 2019, https://clinicaltrials.gov/study/NCT04219527 .

CRITICAL RELEVANCE STATEMENT

Dynamic ultrasound metrics predict early success and pain recurrence following dual-target injections in SIS, offering a longer duration of effectiveness compared to standard subdeltoid-subacromial injections.

KEY POINTS

Dynamic ultrasound metrics predict injection success and pain recurrence in impingement. Dual-target injections offer a longer duration of effectiveness than standard injections. Future research should assess deep learning's predictive value in adhesive capsulitis.