Patellofemoral (knee cap) Dislocation

Who is the leaflet for? What is its aim?

This leaflet aims to answer some of the questions that you may have about managing a dislocated knee cap.

What is a Patellofemoral (knee cap) Dislocation?

The knee cap (patella) is a large bone that sits in front of the knee. It glides in a groove in the thigh bone (femur) allowing you to bend and straighten the leg.

When you dislocate the knee cap it comes out of the groove to the side, causing the tissues around it to be torn and stretched.

A knee cap can dislocate by receiving a direct blow or by a sudden change of direction whilst your foot is planted on the floor.

What is the treatment?

Most of the time the knee cap will go back into the groove on it’s own, but if it doesn’t, it will need to be put back into place by the hospital.

Once your knee cap is back in place it will be swollen and painful, which is to be expected after this injury.

Swelling and bruising of the knee is normal. Simple, over the counter painkillers and applying ice, wrapped in a tea towel, to the area will help to reduce swelling and pain. Ice should be applied for 20 minutes three to four times a day.

If this is your first time dislocating your knee cap, you might be placed in a knee brace to help make your knee feel more comfortable. This should be worn in the first few days following injury whilst the swelling and pain settle, but should be worn for no longer than a week as it could increase the risk of further dislocations.

A referral will be made to physiotherapy following your knee dislocation, however it is important to get started immediately with exercises to strengthen your knee.

Important muscles to strengthen:

• Vastus medialis oblique (VMO) muscle located on the inside of your thigh, which helps to stabilise your knee cap and prevent further dislocation.
• Your gluteal and core muscles, which help to control and stabilise your leg from a more central point in the body.

Ankle pumps

Lying or sitting, pump your ankles towards you and away from you. You can do this with both feet together or alternatively. Complete 20 pumps, 3 times a day

VMO contraction

Lying or sitting, squeeze your thigh muscle particularly on the inner side, pushing your knee down into the bed and try to get your heel to lift. Your knee cap should lift slightly and your thigh muscle should tense. Hold for 5 seconds, repeat 10 times, 3 times a day.

VMO straight leg raise

Lying and sitting, turn your foot out to the side. Push your knee down and squeeze your leg straight. Lift your leg off the bed high enough so that your calf is not touching the bed. Hold for 5 seconds, repeat 10 times, 3 times a day.

Gluteal Muscles

It is very important to strengthen your gluteal (bottom) muscles as these muscles also help provide stability to the leg. Whilst standing, sitting or lying practice squeezing your buttocks and feel yourself rising off the surface. Hold for 5 seconds, repeat 10 times, 3 times a day

You should:

• Wear the brace/splint as directed, to make your knee more comfortable
• Wean out of the splint (leave it off for longer periods of time) if you have been advised to do so
• Exercise to regain strength and movement of your knee if advised to do so
• Start your exercises as soon as you are able

You should not:

• Return to any sports until advised by the physiotherapist or clinic
• Miss any physiotherapy appointments as this is to aid your rehabilitation
• Drive unless able to perform an emergency stop out of the splint

Contacts/ Further Information

Please remember:

Please contact your GP if your condition is not improving, or if your pain relief is not adequate.

If your condition is worsening please contact the Multi professional fracture clinic on 01223 348299 or 01223 257095

For more information please click here to visit the fracture information website.