The Unusual Suspects in Ulnar-Sided Wrist Pain: The Ulnar Styloid Impaction Spectrum

Abstract Ulnar styloid impaction lesions occur secondary to point-loading of the proximal triquetrum by an elongated styloid. This is an uncommon cause of ulnar-sided wrist pain and can be difficult to differentiate from ulnocarpal impaction syndrome. Radiological features are typically only present in advanced lesions resulting in large chondral defects of the triquetrum, thereby making diagnosis difficult. Three cases of patients with nonspecific mechanical ulnar-sided wrist pain and equivocal clinical and radiological findings are used to describe the spectrum of isolated ulnar styloid impaction lesions. The importance of a stepwise approach to wrist arthroscopy as part of the diagnostic workup, and the routine visualization of the pisotriquetral joint in helping identify this lesion is also discussed. Ulnar styloid impaction lesions should be considered in all patients presenting with ulnar-sided wrist pain. Proficiency in diagnostic wrist arthroscopy, with routine inspection of the pisotriquetral joint, is recommended in all patients to identify such lesions, which are commonly not visualized on preoperative imaging. Diagnostic wrist arthroscopy plays a pivotal role in distinguishing between isolated ulnar styloid impaction lesions and other causes of ulnar-sided wrist pain, a distinction that is essential for guiding appropriate therapeutic management.