Irreducible inferior shoulder dislocation requiring open reduction: A case report.

In inferior shoulder dislocation (ISD) cases, closed reduction usually achieves reduction and irreducible ISD is extremely rare. To date, only two cases requiring open reduction have been reported. Herein, we describe a case of an irreducible ISD that required open reduction. A 90-year-old woman fell at home and presented to our hospital. Plain radiography revealed a right ISD and greater tuberosity avulsion fracture. Because reduction under general anesthesia was difficult, we performed open reduction. The humeral head was entrapped by the inferior shoulder capsule. Since inferior instability remained after reduction, we reduced and fixed the greater tuberosity fracture and repaired the rotator cuff tear (RCT). This case suggested that humeral head entrapment by the inferior capsule and decreased force couple toward the humeral head by the greater tuberosity fracture and RCT cause irreducibility. Moreover, since instability can remain after reduction for ISD accompanying greater tuberosity fracture or RCT, preparing for implantations to repair these lesions is recommended.