What is a subluxing patella?
A subluxing patella (kneecap) is a temporary, partial
dislocation of the kneecap from its normal position in the
groove in the end of the thigh bone (femur). This groove is
located between two bumps at the end of the thigh bone called
the femoral condyles.
How does it occur?
This temporary dislocation of the kneecap usually happens
during forced leg straightening, with the kneecap moving out
of the groove to the outer side of the knee.
The cause is usually an abnormality in the way your legs are
built. You may have an underdevelopment of the inner
thigh muscle or an overdevelopment of the outer thigh
muscle. Your kneecap may be higher in the leg than usual.
You may be knock-kneed or have underdevelopment of the
outer (lateral) femoral condyle.
What are the symptoms?
You may feel the kneecap moving out of position. You may
have swelling and pain behind the kneecap. You may have
pain when you bend or straighten your leg.
How is it diagnosed?
Your health care provider will ask about your symptoms and
examine your knee. He or she may be able to feel the
kneecap slipping to the outside as you bend and straighten
your leg. An x-ray may show underdevelopment of the lateral
How is it treated?
Treatment may include:
- putting ice packs on your knee for 20 to 30 minutes every 3 to 4 hours
for the first 2 or 3 days or until the pain goes away
- Elevating your leg with the knee straight. It is best to get your
ankle above the level of your heart.
- taking an anti-inflammatory medication
- wearing a brace prescribed by your health care provider to keep your
kneecap in place
- doing exercises to strengthen the inner side of the thigh muscle (quadriceps).
Some people need surgery to keep the kneecap from subluxing.
While you are recovering from your injury you will need to
change your sport or activity to one that will not make
your condition worse. For example, you may need to bicycle
instead of run.
When can I return to my sport or activity?
The goal of rehabilitation is to return you to your sport or
activity as soon as is safely possible. If you return too
soon you may worsen your injury, which could lead to
permanent damage. Everyone recovers from injury at a
different rate. Return to your sport or activity will be
determined by how soon your knee recovers, not by how many
days or weeks it has been since your injury occurred. In
general, the longer you have symptoms before you start
treatment, the longer it will take to get better.
You may safely return to your sport or activity when,
starting from the top of the list and progressing to the
end, each of the following is true:
- Your injured knee can be fully straightened and bent
- Your knee and leg have regained normal strength compared
to the uninjured knee and leg.
- Your knee is not swollen.
- You are able to jog straight ahead without limping.
- You are able to sprint straight ahead without limping.
- You are able to do 45-degree cuts.
- You are able to do 90-degree cuts.
- You are able to do 20-yard figure-of-eight runs.
- You are able to do 10-yard figure-of-eight runs.
- You are able to jump on both legs without pain and jump
on the injured leg without pain.
If you develop pain, swelling, or the feeling that your
kneecap is moving out of place again, you need to contact
your health care provider.
How can I prevent a subluxing kneecap?
A subluxing kneecap is best prevented by keeping your thigh
muscles strong, especially the group of muscles on the inner
side of the thigh.
To help with consistent knee pain or has a preventive treatment contact jointVitality today. The jointVitality treatment does not help with a knee cap dislocation specifically but it can be treated by our doctors.