Extensor Pollicis Longus Rupture After Distal Radius Fracture: Incidence, Associations, and Functional Outcomes in a Prospective Cohort

Purpose Rupture of the extensor pollicis longus (EPL) tendon is an uncommon but clinically important complication of distal radius fractures. We investigated its incidence, timing, associated factors, and functional consequences in a prospective cohort. Methods This is a secondary analysis of a prospective multicenter cohort at two Swedish orthopedic departments, 2009–2012. Consecutive adults with acute distal radius fractures were enrolled and followed to 12 months. EPL function was assessed by active thumb extension testing at 3 and 12 months. Extensor tendon status was recorded in 419 fractures at 3 months and 373 at 12 months. Associations were analyzed between EPL rupture and age, sex, initial fracture displacement, dorsal comminution, treatment modality, surgical technique, 12-month grip strength, Disabilities of the Arm, Shoulder, and Hand ( Quick DASH), and EQ-5D. Results Ten EPL ruptures were identified among the 419 fractures assessed at 3 months, representing an incidence of 2.4%. One rupture was acute; none occurred between 3 and 12 months. Seven ruptures occurred in undisplaced or minimally displaced fractures, and three occurred in displaced fractures ( P = .06). Four followed surgical treatment, and six followed nonsurgical management. EPL rupture was not significantly associated with age, sex, dorsal comminution, treatment type, or surgical technique. At 12 months, grip strength, Quick DASH, and EQ-5D did not differ significantly between patients with and without EPL rupture. Seven of the 10 patients with rupture underwent tendon transfer; 12-month Quick DASH scores did not differ between these subgroups. Conclusions EPL rupture occurred in 2.4% of distal radius fractures, and all cases occurred within 3 months. No clear demographic, fracture-related, or treatment-related risk factors were identified. Long-term grip strength, function, and quality of life were comparable between patients with and without rupture. Outcomes were acceptable in the few selected patients managed nonsurgically, but the study was not powered to compare treatments. These findings underscore the importance of early surveillance and support an individualized approach. Type of study/level of evidence Prognostic II.