eMedicine Specialties > Emergency Medicine > Trauma & Orthopedics
Dislocation, Wrist: Differential Diagnoses & Workup
Updated: Oct 20, 2008
- Overview
- Differential Diagnoses & Workup
- Treatment & Medication
- Follow-up
- Multimedia
Differential Diagnoses
Arthritis, Rheumatoid
Carpal Tunnel Syndrome
Dislocations, Hand
Fractures, Hand
Fractures, Wrist
Hand Injury, Soft Tissue
Other Problems to Be Considered
With falls onto the outstretched hand, occult scaphoid fracture should always be considered, especially when there is no radiographic evidence of bony fracture. Pain should be elicited in the so-called snuffbox, as well as pain elicited with axial loading of the thumb. Any question of an occult scaphoid fracture should be treated conservatively with a thumb spica splint.
Falls onto the outstretched hand may also produce stress on the distal radioulnar joint (DRUJ), resulting in DRUJ instability. Radiographically, this may manifest itself as a diastema between the distal radius and ulna, resulting in the "Terry Thomas" sign. DRUJ instability should be considered with pain localized to the dorsum of the wrist, between the distal radius and ulna.
Workup
Imaging Studies
- Plain x-rays of the wrist, both anteroposterior (AP) and lateral views, are essential to diagnose wrist dislocations (as well as other carpal instabilities).
- On an AP view, 2 arcs should be identified. The first arc consists of the radiocarpal row, which should be smooth and continuous. Disruption is suggestive of a lunate dislocation.
- The second arc consists of the midcarpal row, which also should be smooth and continuous. Disruption of this arc is suggestive of a perilunate dislocation.
- The appearance of the lunate is important on the AP view. Normally, the lunate is quadrangular. With lunate dislocations, it becomes triangular. This may be an additional clue to dislocation.
- On the lateral view, visualize the column, which consists of the radius, lunate, and capitate. The lunate should lie within the radius cup and the capitate should rest within the lunate cup. Loss of this normal column implies lunate or perilunate dislocation.
- Stress x-rays of the wrist may be necessary to demonstrate intercarpal ligamentous instability when no evidence of wrist dislocation is apparent on plain films.
- Stress x-rays obtained with radial and ulnar deviation of the hand may demonstrate scapholunate dissociation.
More on Dislocation, Wrist |
| Overview: Dislocation, Wrist |
 Differential Diagnoses & Workup: Dislocation, Wrist |
| Treatment & Medication: Dislocation, Wrist |
| Follow-up: Dislocation, Wrist |
| Multimedia: Dislocation, Wrist |
| References |
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References
Carter PR. Fractures and dislocations of the wrist. In: Common Hand Injuries and Infections. 1983:123-141.
Hayden SR. A case of peri-lunate dislocation. J Emerg Med. Mar-Apr 1995;13(2):241. [Medline].
Mital RC, Beeson M. The Wrist and Forearm. Emergency Radiology. 1999;47- 75.
Perron AD, Brady WJ, Keats TE, Hersh RE. Orthopedic pitfalls in the ED: lunate and perilunate injuries. Am J Emerg Med. Mar 2001;19(2):157-62. [Medline].
Rockwood CA, Jr, Green DP, Bucholz RW. Fractures and dislocations of the wrist. In: Fractures in Adults. Lippincott Williams & Wilkins Publishers; 1996:745-867.
Sochart DH, Birdsall PD, Paul AS. Perilunate fracture-dislocation: a continually missed injury. J Accid Emerg Med. May 1996;13(3):213-6. [Medline].
Further Reading
Keywords
wrist dislocation, carpal dislocations, lunate dislocations, perilunate dislocations, scaphoid fractures, wrist injuries, carpal instability, radiocarpal instability
