Knee dislocation: Difference between revisions

Revision as of 19:42, 13 February 2012

Background

Spontaneous reduction occurs in up to 50% of dislocations
- Suggestive by severely injured knee that is unstable in multiple directions
Types
- Anterior (40%)
- Posterior (33%)
- Lateral (18%)
- Medial (4%)

Management

Reduce immediately
1. Apply longitudinal traction
Splint in 20 degrees of flexion
Arteriography?
1. Some recommend for all pts due to high incidence of popliteal artery injury (~33%)
  1. Presence of normal distal pulses does not rule out injury
2. Some only recommend for pts w/ pulse deficit or abnormal ABIs
Ortho and vascular surgery consultation
Admit

Source

Tintinalli

Authors:

@@ Line 1: / Line 1: @@
 ==Background==
+*Spontaneous reduction occurs in up to 50% of dislocations
+**Suggestive by severely injured knee that is unstable in multiple directions
+*Types
+**Anterior (40%)
+**Posterior (33%)
+**Lateral (18%)
+**Medial (4%)
+==Management==
+#Reduce immediately
+##Apply longitudinal traction
+#Splint in 20 degrees of flexion
+#Arteriography?
+##Some recommend for all pts due to high incidence of popliteal artery injury (~33%)
+###Presence of normal distal pulses does not rule out injury
+##Some only recommend for pts w/ pulse deficit or abnormal ABIs
+#Ortho and vascular surgery consultation
+#Admit
-Can result from high- or low-velocity injuries (MVC, martial arts, water-skiing)
+==Source==
+*Tintinalli
-Anterior, posterior, medial, lateral, or rotatory dislocations all possible
-Anterior requires 30o of hyperextension before joint failure
-Posterior usually a dashboard injury
-==Pathophysiology==
-Requires failure of three ligaments
-Popliteal artery injured in 20-30%; if high-velocity then 40%
-hour window...
-==Physical Exam==
-If dislocation is still present, joint injury is easy to diagnose
--Reduce if dislocated!
--Search for hard and soft vascular signs
--If hard vascular signs are present, popliteal artery injury is easy to diagnose
---Hard signs = Pulse deficits, ischemic limb, active hemorrhage, expanding/pulsatile hematoma
---Soft signs = Small/stable hematoma, injury to anatomically related nerve, history of hemorrhage
-Considerations:-Knee may present already reduced
--Finding of significant ligament laxity
--NB: Rate of arterial injury is the SAME, regardless
--Knee swelling is NOT universal
---Knee capsule is frequently disrupted, allowing hemarthrosis to leak into surrounding tissues
--Normal pulses do NOT rule-out a vascular injury
---10% of vascular injuries have normal palpated pulses
-==W/U==
--Xray
-SOFT SIGNS
-Requires further evaluation/studies
--ABI's
--Duplex Doppler Ultrasonography
---Reported sensitivity of 95% and specificity of 99%
---Can miss intimal tears (intimal tears > 30% ofvessel lumen are felt to be “significant”).
-HARD SIGNS
-OR +/- CT Angiogram prior
-==Treatment==
-Reduction, ortho, vascular consult if necessary
-==Consequences==
-Amputation rate:
->8h = 80%
-<8h = 15%
 [[Category:Ortho]]