Ulnar shaft stress fractures in fast-pitch softball pitchers: a case series and proposed mechanism of injury.

Abstract

Stress fractures of the upper extremities in athletes are important injuries for radiologists to appreciate despite being far less common than stress fracturesof the lower extremities. Among upper extremity stress fractures, those involving the olecranon have been well described in overhead pitching athletes. Isolated stressfractures of the ulnar shaft however are less commonly reported in the literature and considered to be rare. We have observed a correlation between young patients withulnar shaft stress fractures and the activity of fast-pitch softball pitching. In this series, we present the imaging findings in four cases of ulnar shaft stressfractures in softball pitchers who presented with insidious onset forearm pain. Furthermore, a review of the literature focusing on softball pitching mechanics isprovided to offer a potential underlying mechanism for the occurrence and location of these injuries. An awareness of the imaging appearance of ulnarshaft stress fractures along with an understanding of its proposed mechanism will facilitate accurate and timely imaging diagnosis of this injury by the radiologist.