Objectives: A prospective study to determine how commonly chronic subacromial impingement is associated with subcoracoid impingement and to evaluate clinical outcome after arthroscopic subacromial decompression (ASD).
Methods: Subacromial and coracohumeral distances were evaluated in patients with chronic shoulder pain before and after ASD, using magnetic resonance imaging and the University of California at Los Angeles (UCLA) shoulder scale and Constant-Murley shoulder assessment.
Results: A total of 40 patients were included in the study; patients were followed up for a mean of 27.3 months. Before ASD, 14 (35%) patients with chronic subacromial impingement also had subcoracoid impingement. In these patients, the mean coracohumeral distance was 7.18 mm (range 5.00 - 11.00 mm). After ASD, no patient had subcoracoid impingement, and the mean coracohumeral distance was significantly longer than pre-ASD, 12.85 mm (range 11.00 - 15.00 mm). The Constant-Murley shoulder assessment and UCLA shoulder scale both showed improvement after ASD.
Conclusions: Chronic subacromial impingement occurred together with subcoracoid impingement in 35% of patients presenting with chronic shoulder pain. Following ASD, the coracohumeral distance increased with remission from pain.