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Unstable Kneecap

What is an unstable kneecap?

The kneecap, or patella, is critical to stability in the knee joint. The kneecap is a small bone located in the front of the knee joint where the thighbone and shinbone meet. It acts as a shield for the joint and connects the muscles in the front of your upper leg to your shinbone. The underside of the kneecap is covered with slippery hyaline cartilage that allows the bones in the joint to glide smoothly as your leg moves.

Because the kneecap connects thigh muscles to the bone in your lower leg, bending and straightening your leg causes the kneecap to be pulled up or down. The kneecap is held in place by a groove in the thighbone. However, if the groove is uneven or too shallow, the kneecap may slide out of place causing partial or complete dislocation. A blow to the kneecap could also pop it out of position in the joint.

Once a kneecap has dislocated, the knee is at greater risk of:

What are the symptoms of an unstable kneecap?

Symptoms of an unstable kneecap include:

How is an unstable kneecap diagnosed?

Your doctor will diagnose an unstable kneecap based on:

Your doctor may also order diagnostic imaging, including an X-ray or MRI, to confirm the diagnosis.

How is an unstable kneecap treated nonsurgically?

Nonsurgical treatment options for a first knee dislocation or unstable kneecap include:

What are the surgical treatment options for an unstable kneecap?

If the kneecap instability becomes chronic, or if you dislocate your knee more than once, you and your doctor may consider surgery to stabilize the kneecap. Surgical options include:

MPFL reconstruction surgery

This is the most common surgery used to address an unstable kneecap.

Tibial tubercle osteotomy

In cases where the patient’s kneecap and shinbone aren’t well aligned, this surgery is used to reposition the bones in the knee joint, thereby stabilizing it.

How long does it take to recover from kneecap stabilization surgery?

Each kneecap stabilization surgery requires a six- to eight-month recovery period. The patient is on crutches for six weeks and then works with a Summit physical therapist to regain motion and rebuild strength.

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