Knee dislocation is when the bones that come together at the knee joint are thrust out of place with great force.  It is very painful and an orthopaedic emergency.

The dislocation usually occurs as the result of a car accident or sports injuries when the knee is bent in an awkward position or over extended.

The area hurts considerably, the leg is swollen and sometimes can look out of place.

During such an injury  it is possible to damage the blood vessels running behind the knee joint.  The most important one  to worry about is the Popliteal artery  taking blood to the leg.  If this is  badly damaged, there is no blood going to the leg and the leg becomes ischaemic and at risk of needing an amputation.

Sometimes the blood vessel is not actually avulsed or transected but the bending damages  its lining  and clot develops  within it having the same effect of reducing blood flow to the leg.

However, although this can occur, it is rare, occurring in about 3% of people who have a full dislocation of the knee.  It is far more common in men than ladies,  and in the age range 20-40 years old

Although the arteries can be damaged, in a lot of cases surgical intervention is not needed and the leg swelling only needs to be observed to ensure it remain fine.  Of those who do have arterial damage, about 13% will need some form of surgical intervention.

The orthopaedic surgeon therefore keeps a very close eye on the blood supply to the leg after such an injury and usually requests a vascular surgeons opinion.  There are a number of investigations which can be  undertaken  such as a Doppler  ultrasound, CT angiogram or MRI.

If vascular surgery is needed, a bypass operation around the damaged vessel  can be considered.  Sometimes it is possible just to tack down the torn area.  Only very rarely (<0/1%) does this result in an amputation at the knee.

If you would like any further information, please email me and I will be able to send you recent clinical papers on this.

Management of Acute Knee Dislocation before Surgical Intervention


Peripheral vascular disease or hardening of the leg arteries causes blockages in these vessels. This affects the quality of life of over two million people in the world.  The severity ranges from severe cramping on walking quickly to  leg ulcers and gangrene.

One of the ways to improve the quality of life and reduce the progression of any ulcers or gangrene is to get more blood down to the legs.  This can be done by doing a bypass operation or opening up the blood vessels with an angioplasty, passing a balloon through the narrowing and opening it up.  Unfortunately, often after an angioplasty the blood vessel thickening up and narrowing down again and the symptoms come back.  To stop this narrowing down happening, a stent or spring can be placed into the vessel. A more recent development has been to apply a chemical to the balloon that reduces the the re-narrowing occurring  (that is intimal hyperplasia).

There are now several studies that show that, if the angioplasty balloon is coated with a chemical that can reduce this happening, the lumen of the blood vessel remains open for much longer.  With this new development gradually being introduced into the  day-to-day management of peripheral vascular disease, there is great optimism that the millions of people who suffer from it will be able to walk further and are less likely to develop gangrene.  A nice review article on this has recently been published and can be obtained free by clicking here. Alternatively if you are concerned please consult a specialist.


Daryll Baker is a Consultant Vascular Surgeon at the Royal Free Hospital London and Clinical Lead for North Central Region Vascular Services.

He read Medicine at Oxford University and trained in Vascular Surgery in Nottingham, London and Edinburgh. He obtained his research PhD from the University of Wales.


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