Perilunate and lunate dislocations: Difference between revisions

Latest revision as of 16:12, 23 March 2020

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
Commonly missed (~25%) on initial presentation
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

Evaluation

Perilunate Dislocation

Lunate Dislocation

Mayfield Classification	Level of carpal instability
Stage I: scapholunate dissociation	Disruption of scapholunate ligament with +Terry Thomas sign; exacerbated in clenched fist view
Stage II: perilunate dislocation	+Disruption of capitolunate joint; high association with scaphoid fractures
Stage III: midcarpal dislocation	+Disruption of triquetrolunate joint; neither capitate or lunate is aligned with distal radius
Stage IV: lunate dislocation	+Disruption of radiolunate joint

Perilunate Dislocation

Lateral view
- Capitate displaced dorsal to lunate
- Lunate retains its normal contact with radius
PA view
- Capitolunate joint space is obliterated as the bones overlap one another

Lunate Dislocation

Lateral view
- Lunate is pushed off the radius into the palm ("spilled teacup" sign)
PA view
- Lunate has triangular shape ("piece-of-pie sign")

Differential Diagnosis

Carpal Dislocations

Carpal fractures

AP view

Management

Closed reduction and long-arm splint
- Requires emergent ortho consultation (very difficult to reduce with high incidence of median nerve compression), and usually emergent operative management

References

Emergency Orthopedics, The Extremeties
Radiopaedia.org

Authors:

@@ Line 1: / Line 1: @@
-== Lunate and Perilunate Dislocation  ==
+==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
+*Commonly missed (~25%) on initial presentation
+*Must rule-out median nerve injury
+*Must rule out carpal bone fractures
-'''Background'''
+==Clinical Features==
+*Perilunate dislocation: dorsal swelling with palpable mass
+*Lunate dislocation: volar swelling with palpable mass
-• Perilunate Dislocation<br>
+==Evaluation==
+[[File:Perilunate Dislocation.jpg|thumb|Perilunate Dislocation]]
+[[File:Lunate_Dislocation.jpg|thumb|Lunate Dislocation]]
+{| class="wikitable"
+|-
+! Mayfield Classification !! Level of carpal instability
+|-
+| Stage I: scapholunate dissociation || Disruption of scapholunate ligament with +Terry Thomas sign; exacerbated in clenched fist view
+|-
+| Stage II: perilunate dislocation || +Disruption of capitolunate joint; high association with scaphoid fractures
+|-
+| Stage III:  midcarpal dislocation || +Disruption of triquetrolunate joint; neither capitate or lunate is aligned with distal radius
+|-
+| Stage IV: lunate dislocation || +Disruption of radiolunate joint
+|}
-&nbsp; · Dorsal displacement of capitate in relation to lunate<br>
+===Perilunate Dislocation===
+*Lateral view
+**Capitate displaced dorsal to lunate
+**Lunate retains its normal contact with radius
+*PA view
+**Capitolunate joint space is obliterated as the bones overlap one another
-&nbsp; · Note that the radius, capitate, lunate, and third metacarpal form a straight line on lateral x-ray<br>
+===Lunate Dislocation===
+*Lateral view
+**Lunate is pushed off the radius into the palm ("spilled teacup" sign)
+*PA view
+**Lunate has triangular shape ("piece-of-pie sign")
-• Lunate Dislocation<br>
+==Differential Diagnosis==
+{{Carpal dislocation DDX}}
-&nbsp; · Volar dislocation of the lunate in relation to the radius, spilled teacup<br>
+{{Carpal fractures}}
-'''Clinical Features'''
+==Management==
+*Closed reduction and long-arm splint
+**Requires emergent ortho consultation (very difficult to reduce with high incidence of median nerve compression), and usually emergent operative management
-• FOOSH injury with excessive hyperextension, ulnar deviation, and intercarpal supination
+==See Also==
+*[[Carpal dislocations]]
-• On exam, decreased range of motion with focal swelling<br>
+==References==
+<references/>
+*Emergency Orthopedics, The Extremeties
+*Radiopaedia.org
-&nbsp; · Dorsal swelling with mass in perilunate dislocation<br>&nbsp; · Volar swelling with palpable mass in lunate dislocation<br>
-• Median nerve compression possible, perform thorough neurovascular exam
+[[Category:Orthopedics]]
-• Scaphoid fractures and scaphoid rotary subluxation are common
-• Degenerative arthritis is very common, 60% incidence
-'''Workup'''
-• X-ray, wrist series, minimum of three views<br>
-• Perilunate dislocation
-&nbsp; · Lateral view, dorsal dislocation of capitate when an imaginary line is drawn through radius, luante, and capitate
-&nbsp; · PA view, capitate and lunate overlap
-• Lunate dislocation
-&nbsp; · Lateral view, lunate displaced and tilted volarly
-&nbsp; · PA view, lunate is triangular in shape
-'''Differential Diagnosis'''
-• Fractures of the distal radius
-• Fractures of the carpal bones, the scaphoid being the most common
-• Scapholunate dissociation
-• Ligamentous injury
-• Septic arthritis
-'''Treatment'''
-• Immediate orthopedic consult for closed vs open reduction
-&nbsp; · The longer the dislocation is left unreduced, the lower the likelihood of reduction
-• In ED, volar splint in neutral
-'''Sources'''
-• Emergency Orthopedics, The Extremeties
-• Radiopaedia.org
-[[Image:PL 1.jpg|thumb|left|200x264px|PL 1.jpg]]<br>
-[[Image:PL 2.jpg|thumb|center|279x293px|PL 2.jpg]]
-[[Image:Lun 1.jpg|thumb|left|201x299px|Lun 1.jpg]]