Extensor pollicis longus tendon rupture caused by a displaced dorsal “beak” fragment of Lister’s tubercle in distal radius fractures

Abstract Introduction Ruptures of the extensor pollicis longus (EPL) tendon are a well-known complication of distal radius fractures (DRF). There are a lot of suspected mechanisms, including mechanical friction, vascular impairment, injury associated with reduction, and local adhesion. However, there have been limited reports about a closed rupture of the EPL tendon associated with a relatively large, displaced dorsal “beak” fracture fragment. We report about the management outcomes and clinical significance of closed ruptures of the EPL tendon caused by a displaced dorsal fracture fragment of beak-like appearance in DRF. Patients/Material and Methods Our study included 7 cases of a complete closed rupture of the EPL tendon after open reduction internal fixation. All cases showed a similar pattern involving a relatively large dorsal beak fragment originating from Lister’s tubercle, and we treated them with a palmar locking plate within 7 days from the initial fracture without separate dorsal fragment management. All patients were diagnosed with a delayed EPL tendon rupture. Results The study included 5 female and 2 male patients. Mean patient age was 59 years. In all cases we explored the extensor compartment III to verify the exact cause of the EPL rupture. Six patients underwent an extensor indicis transfer and one patient underwent tendon grafting. Mean fragment width and length were 7.0 mm and 13.3 mm, respectively. The fragments were dorsally elevated (mean, 2.4 mm) and distally displaced (mean, 3.5 mm). At the last follow-up, the mean DASH score was 4.4. Mean thumb MP joint flexion and extension were 4 degrees and 62 degrees, respectively. Conclusion We support the possibility of EPL tendon rupture caused by displaced sharp Lister’s tubercle fracture fragments.