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Is the lateral extension of the acromion related to the outcome of shoulder injections?

Tobias Johannes Dietrich, Beat K Moor, Gabor Puskas, Christian W A Pfirrmann, Juerg Hodler & Cynthia K Peterson

abstract

OBJECTIVE
To assess patients' outcomes after subacromial or glenohumeral injections based on the degree of lateral extension of the acromion.

METHODS
307 patients were prospectively included after therapeutic fluoroscopy-guided subacromial (n = 148) or glenohumeral (n = 159) injections with anaesthetic and long-acting corticosteroids. Pre- and post-injection outcomes at 1 week and 1 month were obtained using the 11-point numerical rating scale (NRS) for pain. Lateral extension of the acromion was quantified and categorized by the critical shoulder angle (CSA) and the acromion index (AI) on anteroposterior conventional radiographs.

RESULTS
Patients' outcomes at 1 week and 1 month were significantly improved (p < 0.001) compared to baseline for subacromial and glenohumeral injection patients. Patients with a CSA <35° showed significantly higher pain reduction 1 month after subacromial injection compared to patients with a CSA >35° (4.2 ± 2.6 vs. 3.2 ± 3.0, p = 0.04). A significant difference in the 1-month NRS change in pain scores is noted for smaller AIs after subacromial injection (4.3 ± 2.8 vs. 2.6 ± 2.9; p = 0.01). No significant association was noted between clinical outcome and the lateral extension of the acromion after glenohumeral joint injections.

CONCLUSIONS
A short lateral extension of the acromion was associated with better clinical outcomes in subacromial injection patients but not in glenohumeral injection patients.

KEY POINTS
• Patients' outcomes at 1 month improved significantly compared to baseline for subacromial injections. • Patients' outcomes at 1 month improved significantly compared to baseline for glenohumeral injections. • Short acromial lateralization was associated with better clinical outcome after subacromial injection. • The acromial lateralization was not associated with clinical outcome after glenohumeral injection.
   
citation Dietrich T J, Moor B K, Puskas G, Pfirrmann C W A, Hodler J, Peterson C K. Is the lateral extension of the acromion related to the outcome of shoulder injections?. Eur Radiol 2014; 25:267-73.
   
type journal paper/review (English)
date of publishing 29-08-2014
journal title Eur Radiol (25/1)
ISSN electronic 1432-1084
pages 267-73
PubMed 25163903
DOI 10.1007/s00330-014-3403-7