Dislocation of the Knee

[studyinghard]

I'm an MS1 and we're covering limbs in anatomy right now. We had a case in PBL where a patient's knee was traumatically dislocated anteriorly. How is an emergent reduction performed? Exactly where is the traction?

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[moquito_17]

Before beginning, know that a dislocated joint is an orthopaedic emergency and should not be taken lightly. If there is neurovascular comprimise and the dx is obvious, relocation shoud be done immidiately, before EMS transfer, before X-rays, before leaving the ED etc.

To do:
1) Sedation
2) Axial traction (pull the lower leg distally)
3) The knee may relocate spontaneously with axial traction. Otherwise, you apply force to the proximal tibial opposite the direction of dislocation.
3a) Open reduction if closed is not sucessful. This is susally due to a piece of interposed soft tissue.
4) Post-reduction x-rays
5) Follow-up MRI, ACL/PCL reconstruction, knee braces etc.

Does that answer your question?

 

[dobonedoc]

Best make sure your vascular exam is normal. This means close documentaiton of distal pulses, and the ankle/brachial index.

 

[yowhassupdude]

should an abnormal vascular exam (eg no pulses) change your management? Would you delay immediate reduction pending angiogram?

 

[dry dre]

should an abnormal vascular exam (eg no pulses) change your management? Would you delay immediate reduction pending angiogram?

In general, when a joint is dislocated and distal pulses are lost, reducing the joint may restore bloodflow. If/once bloodflow is restored, qhour vascular checks are required for ~24/48 hours. Vascular consultation for possible damage, including intimal tears, is usually (but not always) required.

In general, the rule is to bend things straight as soon as possible (fractures or dislocations) with proper technique that is situation specific.

 

[dpmd]

One reason to document well the neurovascular exam is in the event it is compromised following your manipulation. If you didn't document the status before you started, you leave yourself open for lawsuits. I am not saying you need to get an angiogram before doing anything. But if the pulse is present, you can quickly check ABI's along with doing a quick motor and sensory exam (although I guess it might be tough to convince someone to wiggle their toes with their knee dislocated).