Retained palmar foreign body presenting as a late hand infection: proposed diagnostic algorithm to detect radiolucent objects

BACKGROUND: Penetrating injuries to the hand can compromise important anatomic structures, and persisting foreign objects may become a source of infection. Foreign body intrusions into the hand are among the most common injuries to the upper extremity seen in the Emergency Department. Radiolucent organic objects, as well as a few higher density inorganic materials such as plastic, present a diagnostic challenge and are routinely missed using standard radiography. While the literature describes the use of high-frequency ultrasound as an adjunct to conventional diagnostics, to our knowledge, no formal algorithm has been published. CASE PRESENTATION: We describe a case of incomplete wooden splinter removal, presenting as a late midpalmar abscess five months after the initial injury, and requiring two subsequent surgical explorations for definitive treatment. This case has led us to implement a formal diagnostic pathway including high-frequency ultrasound at our institution. We contrast this presentation with a subsequent case involving a much smaller wooden palmar foreign body that was easily identified under ultrasound and removed without sequelae. CONCLUSION: Many hand injuries are caused by low density, radiolucent foreign bodies. These objects can easily escape traditional evaluation in the emergency room including standard radiography. We present an algorithm implementing high frequency ultrasound to minimize the risk of missing radiolucent penetrating foreign objects in the hand.