Perilunate and lunate dislocations: Difference between revisions

Revision as of 20:19, 7 February 2012

Background

Occur via high-energy FOOSH injury (fall from height, MVC)
- Perilunate Dislocation = Lunate stays in place, capitate is displaced
- Lunate Dislocation = Capitate stays in place, lunate is displaced
Must rule-out median nerve injury
Must rule out carpal bone fractures

Clinical Features

Perilunate dislocation: dorsal swelling with palpable mass
Lunate dislocation: volar swelling with palpable mass

Diagnosis

Perilunate Dislocation
- Lateral view
  - Capitate displaced dorsal to lunate
  - Lunate retains its normal contact w/ radius
- PA view
  - Capitolunate joint space is obliterated as the bones overlap one another
Lunate Dislocation
- PA view
  - Lunate has triangular shape ("piece-of-pie sign")
- Lateral view
  - Lunate is pushed off the radius into the palm ("spilled teacup" sign)

DDX

Fractures of distal radius, carpal bones (esp scaphoid)
Scapholunate Dissociation

Treatment

Both dislocations require emergent ortho consultation (very difficult to reduce)
Closed reduction and long-arm splint

Source

Emergency Orthopedics, The Extremeties
Radiopaedia.org
Tintinalli

File:PL 1.jpg

Perilunate lateral

File:PL 2.jpg

Perilunate AP

File:Lun 1.jpg

Lunate

Authors:

@@ Line 1: / Line 1: @@
 == Background ==
-*Perilunate Dislocation
+*Occur via high-energy FOOSH injury (fall from height, MVC)
-**Dorsal displacement of capitate in relation to lunate
+**Perilunate Dislocation = Lunate stays in place, capitate is displaced
-**Note that radius, capitate, lunate, and 3rd metacarpal form straight line on lat x-ray
+**Lunate Dislocation = Capitate stays in place, lunate is displaced
-*Lunate Dislocation
+*Must rule-out median nerve injury
-**Volar dislocation of the lunate in relation to the radius, spilled teacup<br>
+*Must rule out carpal bone fractures
 == Clinical Features ==
-*FOOSH injury with excessive hyperextension, ulnar deviation, and intercarpal supination
+*Perilunate dislocation: dorsal swelling with palpable mass
-*On exam, decreased range of motion with focal swelling
+*Lunate dislocation: volar swelling with palpable mass
-**Dorsal swelling with mass in perilunate dislocation
-**Volar swelling with palpable mass in lunate dislocation
-*Median nerve compression possible, perform thorough neurovascular exam
-*Scaphoid fractures and scaphoid rotary subluxation are common
-*Degenerative arthritis is very common, 60% incidence
-== Workup ==
+== Diagnosis ==
-*X-ray: wrist series, minimum of three views
+*Perilunate Dislocation
-*Perilunate dislocation
+**Lateral view
-**Lateral view, dorsal dislocation of capitate when an imaginary line is drawn through radius, luante, and capitate
+***Capitate displaced dorsal to lunate
-**PA view, capitate and lunate overlap
+***Lunate retains its normal contact w/ radius
-*Lunate dislocation
+**PA view
-**Lateral view, lunate displaced and tilted volarly
+***Capitolunate joint space is obliterated as the bones overlap one another
-**PA view, lunate is triangular in shape
+*Lunate Dislocation
+**PA view
+***Lunate has triangular shape ("piece-of-pie sign")
+**Lateral view
+***Lunate is pushed off the radius into the palm ("spilled teacup" sign)
 ==DDX ==
-#Fractures of the distal radius
+#Fractures of distal radius, carpal bones (esp scaphoid)
-#Fractures of the carpal bones, the scaphoid being the most common
 #[[Scapholunate Dissociation]]
-#Ligamentous injury
-#Septic arthritis
 == Treatment ==
-#Consult hand surgeon for immediate reduction (very difficult to reduce)
+#Both dislocations require emergent ortho consultation (very difficult to reduce)
-#Volar splint in neutral position
+#Closed reduction and long-arm splint
 == Source ==
 *Emergency Orthopedics, The Extremeties
 *Radiopaedia.org
+*Tintinalli
 [[Image:PL 1.jpg|thumb|left|200x264px|PL 1.jpg|Perilunate lateral]]<br>