Extensor Tendon Entrapment on Computed Tomography Imaging of Distal Radius Fractures

Abstract

Objective To examine the association between distal radius fractures and tendon entrapment identified on computed tomography (CT) imaging. Patients and Methods After Institutional Review Board approval, we retrospectively reviewed distal radius fractures that underwent CT imaging from an electronic database between January 2006 to February 2018 at a single level 1 hospital trauma center. We categorized all distal radial fractures according to the AO-OTA (AO Foundation/Orthopaedic Trauma Association) classification. Distal upper extremity tendons were assessed for entrapment. Fisher's exact test was used for statistical analysis with significance at p < 0.05. Results A total of 183 distal radius fractures were identified in 179 patients. A total of 16 fractures (13 males and 3 females) were associated with tendon entrapment. Mechanism of injury included falls ( n = 7), motor vehicle accidents ( n = 6), dog bites ( n = 2), and gunshot wound ( n = 1). Entrapped tendons were limited to the extensor compartment and included the extensor pollicis longus (EPL; n = 11), extensor pollicis brevis ( n = 1), extensor carpi ulnaris ( n = 1), extensor carpi radialis longus ( n = 1), and extensor digitorum communis ( n = 2). The most commonly associated AO-OTA fracture pattern with tendon entrapment was complete articular radial fractures (2R3C; 69%), eight of which were simple articular with metaphyseal multifragmentary fractures (2R3C2). Of the distal radius fractures, 81% were associated with additional ulnar fractures of varying severity and displacement. Conclusion Approximately 8.7% of distal radius fractures were retrospectively identified to have tendon entrapment compared with a previously reported incidence of 1.3%. Wrist surgeons and radiologists should have higher suspicion for tendon entrapment and carefully review preoperative CT imaging for tendon entrapment in distal radius fractures especially if there is an intra-articular, multifragmentary injury pattern. Wrist surgeons and radiologists should also have increased suspicion for EPL tendon entrapments given its high incidence in association with distal radius fractures. Level of Evidence This is a Level III, retrospective cross-sectional study.

Keywords: AO-OTA classification; computed tomography; distal radius fracture; tendon entrapment.

Fig. 1

Axial CT (computed tomography) scan of a 70-year-old male who fell from standing and sustained a highly comminuted distal radius fracture with intra-articular extension of the radiocarpal and radioulnar joint space (AO-OTA [AO Foundation/Orthopaedic Trauma Association] classification 2R3C2.1T). There is dorsal displacement of the fracture fragments with extensor pollicis longus tendon entrapment with fracture fragments involving Lister's tubercle ( arrow ).

Fig. 2

CT (computed tomography) scan of a 58-year-old female who fell approximately 5 feet from a boat and sustained a closed comminuted distal radius fracture with 3 mm of impaction and 1 to 2 mm of step-off at the radiocarpal articular surface (AO-OTA [AO Foundation/Orthopaedic Trauma Association] classification 2R3C3.2). The extensor pollicis brevis is shown to be entrapped within the comminuted fracture ( arrow ).

Fig. 3

CT (computed tomography) scan of a 48-year-old female who was attacked by a dog and sustained an open, highly comminuted, shattered, and impacted fracture of the distal ulna and radial styloid avulsion (not shown) with associated disruption and widening of the distal radial ulnar joint (AO-OTA [AO Foundation/Orthopaedic Trauma Association] classification 2U3C). There is entrapment of the extensor carpi ulnaris within the ulnar fragments ( arrow ).

Fig. 4

CT (computed tomography) scan of a 21-year-old female who was involved in a motor vehicle collision and sustained a comminuted distal radius fracture with high comminution of the radial styloid (AO-OTA [AO Foundation/Orthopaedic Trauma Association] classification 2R3B1.1). There is partial entrapment of the extensor carpi radialis longus tendon ( arrow ).

Fig. 5

CT (computed tomography) scan of a 29-year-old male who was involved in a motorcycle crash and sustained a highly comminuted intra-articular fracture of the distal radius (AO-OTA [AO Foundation/Orthopaedic Trauma Association] classification 2R3C2.1U). The extensor digitorum communis is shown to be entrapped at the sites identified ( arrows ), with significant distal radial ulnar joint instability.