Background: A rupture of the extensor pollicis longus (EPL) tendon located close to the Lister tubercle is an uncommon complication of distal radius fractures. This study aimed to determine whether the size and shape of Lister tubercle in patients with EPL rupture differs from a matched group of patients with distal radius fractures without EPL rupture. Methods: We identified 15 patients with EPL rupture (3.5%) out of 426 with distal radius fractures treated conservatively at our hospital over 4 years. Out of the remaining 411 patients with distal radius fractures without EPL rupture, we selected patients using simple random sampling and pseudo-randomised them such that their age, sex and fracture type were matched with patients exhibiting EPL rupture. The size and shape of the Lister tubercle and the size of the EPL groove were measured in both groups using computed tomographic scans and compared. Results: There was no difference in the size of the Lister tubercle or the EPL groove between both groups. A 'hook'-shaped Lister tubercle was noted in 8 out of 15 patients with EPL rupture but in only 1 out of 15 matched patients without EPL rupture. Conclusions: A 'hook'-shaped Lister tubercle was seen more often in patients with EPL rupture following distal radius fracture. Level of Evidence: Level III (Therapeutic).
Keywords: Distal radius fracture; Extensor pollicis longus; Hook shape deformation; Lister tubercle; Tendon rupture.