Epidemiology: This is a commonly missed injury. Missed diagnoses lead to chronic instability .
Symptoms: Patients can sometimes have unremarkable or subtle exams. They may have tenderness to palpation or swelling on the volar aspect of the wrist.
Diagnostic Imaging: Disruption of Gilula’s arcs on AP. The lunate may appear as a “piece of the pie (Figure 4). These injuries are most pronounced on lateral films.
Figure 4: AP of wrist showing “Piece of Pie”. Note disruption of Gilula’s Lines. Case courtesy of Dr Andrew Dixon, Radiopaedia.org.
- Perilunate dislocation: The lunate is in line with radius but the capitate appears dislocated.
- Lunate dislocation: Capitate and radius are in line, the lunate is not (Figures 5, 6).
Treatment: Check for sensation and function of the median nerve.
- Reduce with longitudinal traction and wrist extension.
- Apply pressure on the volar aspect of the wrist in dorsal direction with flexion.
- Place in sugar tong and arrange for 1-2 day follow-up if reduction is successful.
- If reduction fails, orthopedics should be consulted emergently .
Figure 5: Pictorial representation of a lunate and perilunate dislocation.
Figure 6: A) normal lateral view. B) lateral view demonstrating lunate dislocation. C) lateral view demonstrating perilunate dislocation. Cases courtesy of Dr Jeremy Jones, Radiopaedia.org, Dr Andrew Dixon, Radiopaedia.org, and Dr Andrew Dixon, Radiopaedia.org. Annotations by Stephen Villa
Want more information about these injuries? Check out CoreEM Post on perilunate/lunate dislocations.