Figure 1. Anteroposterior view of the fracture. Credit: Dagan Cloutier, MPAS, PA-C
Figure 2. Lateral view of the fracture. Credit: Dagan Cloutier, MPAS, PA-C
A 28-year-old woman presents with an inability to extend her right thumb since yesterday. She was recently treated for a nondisplaced distal radius fracture with a short arm cast for 4 weeks and was transitioned to a removable splint over the last week (Figures 1 and 2). The patient explains that when she was grabbing an object yesterday, she felt a pop in her thumb and lost the ability to extend the tip of her thumb. On physical examination, she cannot actively extend the interphalangeal joint of her right thumb. She has difficulty with abduction of the thumb as well. She is otherwise neurologically intact.
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One infrequent but not to be missed complication of a distal radius fracture is extensor pollicis longus (EPL) tendon rupture. The classic presentation is a patient presenting with inability to extend the thumb during or just after treatment of a nondisplaced distal radius fracture. The incidence can vary from 0.4% to 5% of all distal radius fractures and most cases occur with minimally displaced to nondisplaced types.1,2
Multiple etiologies have been proposed to explain the rupture, including laceration of the tendon on a spike of bone, disturbed blood supply to the tendon because of local swelling, and local adhesions. Tendon rupture occurs on average at 9 weeks after the initial injury (range 3-16 weeks) when treated nonoperatively. Treatment of the tendon rupture includes surgical repair with an extensor indicis proprius to extensor pollicis longus tendon transfer with the goal of restoring thumb extension.1,2
Dagan Cloutier, MPAS, PA-C, practices in a multispecialty orthopedic group in the southern New Hampshire region and is editor in chief of the Journal of Orthopedics for Physician Assistants.
1. Roth KM, Blazar PE, Earp BE, Han R, Leung A. Incidence of extensor pollicis longus tendon rupture after nondisplaced distal radius fractures. J Hand Surg Am. 2012;37(5):942-947. doi:10.1016/j.jhsa.2012.02.006
2. White BD, Nydick JA, Karsky D, Williams BD, Hess AV, Stone JD. Incidence and clinical outcomes of tendon rupture following distal radius fracture. J Hand Surg Am. 2012;37(10):2035-2040. doi:10.1016/j.jhsa.2012.06.041