Purpose: the present prospective open-label study was designed to gain further insights into a condition thought to constitute a neglected but not uncommon syndrome characterized by anterior shoulder pain and tenderness to palpation over the apex of the coracoid process, not related to rotator cuff or pectoralis minor tendinopathy, long head of the biceps tendon disorders, or instability. The aim was to clarify its prevalence, clinical characteristics, differential diagnosis and response to corticosteroid injections.
Methods: patients with primary anterior shoulder pain precisely reproduced by deep pressure on the apex of the coracoid process were recruited. Patients with clinical or instrumental signs of other shoulder disorders were excluded. Patients were given an injection of triamcinolone acetonide 40 mg/ml 1 ml at the coracoid trigger point. They were evaluated after 15, 30 and 60 days and at 2 years using Equal Visual Analog Scale (EQ-VAS) and the Italian version of the Simple Shoulder Test (SST).
Results: between January 1 and December 31 2010, we treated 15 patients aged 26-66 years. The majority were women (86.67%). At 15 days, 6 (40%) patients reported complete resolution of their symptoms, while 9 (60%) complained of residual symptoms and received another injection. At 30 days, 14 (93.33%) patients were pain-free and very satisfied. At 2 years, the 14 patients who had been asymptomatic at 30 days reported that they had experienced no further pain or impaired shoulder function. The analysis of variance for repeated measures showed a significant effect of time on EQ-VAS and SST scores.
Conclusions: the present study documents the existence, and characteristics, of a "coracoid syndrome" characterized by anterior shoulder pain and tenderness to palpation over the apex of the coracoid process and showed that the pain is usually amenable to steroid treatment. This syndrome should be clearly distinguished from anterior shoulder pain due to other causes, in order to avoid inappropriate conservative or surgical treatment.
Level of evidence: Level IV, therapeutic case series.
Keywords: anterior shoulder pain; coracoid; enthesitis; syndrome.