How would the knee dislocate?
You knee may dislocate to the front, back and sides. However the commonly seen type is the knee dislocating to the back. For a knee to dislocated there has to be damaged to three out of four ligaments which hold the knee in place while you walk. The knee cap too can be fracture in knee dislocations.
A violent force acting on the knee when it is bent to 90 degrees will dislocated to the back.
What else could get injured?
Blood vessels and nerves that serve the leg, ankle and foot run just behind the knee. They could get damaged with this injury. The damage could be over stretching, partial tear or complete separation.
Are there immediate complications?
Your leg/knee will look deformed. You will not be able to move it.
If oxygen supply to the leg is compromised, the leg will swell. The toes and foot feel numb. There will be excruciating pain.
Your knee will be relocated to its normal position without delay and supported in a plaster of Paris half cast.
In certain occasions it could be fixed to a metal frame.
Damage to blood vessels and nerve will require additional investigations and surgical procedures which are done urgently.
The definitive treatment for knee dislocation could wait till these procedures are complete.
When conditions are favorable you will be subjected to further imaging to see ligament injuries. MRI is the test of choice.
Is it a big operation?
The knee is managed with plaster of Paris slab initially. The knee can be mobilized in a hinged knee brace. Knee bending is started with this.
Any remaining instability will be addressed as required.
Two ligaments inside the joint can be repaired by a keyhole surgical procedure.
Time periods of recovery ?
Initial immobilization will be about six weeks. You will need another period of six weeks for physiotherapy before being fully functional