Risk factors for extensor pollicis longus tendon rupture following non-displaced distal radius fractures.

Background: Distal radius fractures (DRFs) are common, with an increasing incidence, particularly among the elderly. Rupture of the extensor pollicis longus (EPL) tendon, essential for thumb extension, is a notable complication, especially in non-displaced DRFs. Several mechanisms, such as local adhesion, ischemic atrophy, and tendon laceration, are associated with EPL tendon rupture. This multicenter retrospective study aims to identify risk factors for EPL tendon rupture in non-displaced DRFs.

Methods: The study reviewed 20 cases of EPL tendon rupture and 52 control cases from 2005 to 2022, excluding those who underwent surgery or had incomplete computed tomography (CT) data. We investigated age, sex, location of fracture line, and the morphology of Lister's tubercle as variables. Logistic regression and decision tree analyses were employed to determine the risk factors for EPL tendon rupture based on these variables.

Results: Fracture lines distal to Lister's tubercle and specific shapes of Lister's tubercle, characterized by shallow peak height and a higher radial peak than the ulnar peak, increased the risk of EPL tendon rupture. Decision tree analysis confirmed them as major risk factors. There was a significant difference in the predicted probability rate of tendon rupture between the case with these factors and those without them (P < 0.001). Conversely, the location and size of Lister's tubercle did not affect the incidence of EPL tendon rupture.

Conclusions: The location of fracture line and the shape of Lister's tubercle are key factors influencing EPL tendon rupture in non-displaced DRFs. Understanding these factors can help orthopedic surgeons predict and prevent EPL tendon ruptures, improving patient outcomes following these fractures.