A 37-year-old female presented with left knee pain after being in a motor vehicle collision where her knee struck the dashboard. On examination, her left knee was grossly unstable and unable to extend with decreased sensation over the lateral foot. She likely suffered a posterior knee dislocation with injuries to both cruciate ligaments, the popliteal artery, and nerves. Treatment requires reduction, immobilization, assessment of vascular injury such as with CT angiography, and emergent orthopedic referral.

2.  37 yo female p/w knee
pain s/p front-end MVC
as a restrained passenger
with the left knee striking
the dashboard. Pt cannot
move knee secondary to
pain. No other injuries
noted.
 T 98.7 P 103 BP 117/62 O2





100%
Gen:
CV: Tachycardic, RR, no
m/r/g
Pulm: Lungs CTA bilat
GU: nml
Ext: Left knee grossly
unstable and unable to
extended. Decreased
sensation over lateral
foot.

5.  25% knee dislocations
 Both Cruciate Ligament disruption (ACL & PCL)
 Popliteal artery injury
 Behind the lateral meniscus, posterior to Tibial Plateau
 Less common than anterior dislocation as extensor
mechanisms provide protection from anterior
 Nerve Injury (16-40%)
 Tibial and Fibular nerve 2/2 traction

6.  Reduction with traction/ countertraction
 Avoid compression in the popliteal space
 Immobilization
 Long-Leg post splint in 15 degrees flexion (less tension
popliteal a.)

7.  Assessment of Vascular Injury
 Perform ABI vs CT Angio of lower extremity given high
risk of popliteal artery injury
 If injury present  Emergent Vascular Surgery c/s
 Emergent Orthopedic referral
 Admit for vascular rechecks  compartment syndrome
 Likely operative repair 10-14 days with decreased
swelling

8.  http://www.imageinterpretation.co.uk/pelvis.html
 http://www.wheelessonline.com/ortho/12846
 Redmond, Levy, Dajani, et al. Detecting Vascular Injury in
Lower-Extremity Orthopedic Trauma: The Role of CT
Angiography. ORTHOPEDICS. August 2008;31(8):761.
 http://www.wheelessonline.com/ortho/traumatic_dislocat
ions_of_the_knee
 http://reference.medscape.com/features/slideshow/lwrdisloc
 http://www.accessemergencymedicine.com/overflow.aspx?
searchStr=dislocations&hasExactMatch=True&hasDrugMa
tch=False&searchSource=Images&ftbool=False