Nonunion of the coracoid process: a systematic review.

INTRODUCTION: Although the coracoid process seems to play an important anatomical role, there are few reports concerning fracture nonunion of the coracoid process (CN) and its disorders. Therefore, there is no widely accepted standard for the treatment of CN. MATERIALS AND METHODS: PubMed and Scopus were searched using "scapular fracture" and "coracoid fracture" as search terms. The inclusion criteria were English full-text articles concerning coracoid fracture, and articles that described patient characteristics and presented appropriate images. The exclusion criteria were descriptive cases, and cases without appropriate images. Citation tracking was conducted to find additional articles and notable full-text articles written in other languages. Fractures were classified using Ogawa's functional classification, with Eyres' anatomical classification used as a supplement when necessary. RESULTS: Twenty-nine patients (26 men, 3 women) with 30 CN were identified. Nine CN had a predisposing factor such as seizure disorder and renal osteodystrophy. The fracture types were 12 Ogawa type I and 18 type II. Concurrent shoulder girdle injuries at the time of initial trauma/accident were varied. There were six cases of double disruption and two of triple disruption of the superior shoulder suspensory complex (SSSC), all of which had Ogawa type I fracture. Only six CN were isolated. The most frequent cause of CN was oversight by the previous physician (n = 11), followed by conservative treatment (n = 7). Although 12 patients with 13 CN had symptoms attributable to CN, most of these symptoms were insignificant. Although the acromioclavicular dislocation or CN persisted in eight patients, these residual abnormalities did not significantly affect the outcomes. CONCLUSIONS: Physicians treating CN should recognize that CN itself is frequently asymptomatic, and a satisfactory outcome is achieved solely by treating the concurrent injuries, even if CN remains. When CN is suspected to produce symptoms, the physician must then determine the mechanism by which the symptoms are produced, and select a treatment strategy. LEVEL OF EVIDENCE: V.