Recurrent Patellar Dislocation occurs when the kneecap slides out of place. The patella is the bone more commonly known as the kneecap. It fits securely in a V-shaped groove in front of the knee and moves up and down when the leg is bent or straightened.

When the medial patellofemoral ligament on the inside of the knee tears as a result of patellar dislocation, you might need reconstructive surgery.

These tears are caused by anatomic variables like:

1. Knock knees — knees angled inward and touching when the legs are straight
2. Rotation of thigh or leg bone

These conditions might need an osteotomy to correct the alignment by reshaping the bone or moving the attachment of the patella tendon. In special circumstances, the groove the kneecap should ride in is either absent or shaped like a rounded dome rather than as a "V" shape. This can result in instability that can be disabling, and it can only be corrected with surgery called trochleoplasty.

Factors that may increase your chance of patellar dislocation include:

1. Weak thigh muscles
2. A patella that sits too high on the thigh bone
3. Excess pronation of the feet — inward roll of the feet when walking or running
4. Weak and stretched ligaments from previous patellar dislocations

Symptoms of Recurrent Patellar Dislocation

Patellar dislocation may cause:

1. Extreme pain and swelling at the knee
2. Buckling under your own weight
3. A sense of the kneecap sliding to the side
4. Abnormal appearance of the knee

Diagnosis & Treatment

Your doctor will perform an exam of your patella to check for tenderness and swelling.

Images of your knee can be taken with:

1. X-rays
2. CT scan
3. MRI scan

Trochleoplasty Surgery

Trochleoplasty involves your surgeon reshaping the trochlear groove, the v-shaped groove in front of the knee. The amount of bone that your surgeon removes varies from patient to patient.

Arthritis and age factor into whether you will have a good result.

If you’re considering trochleoplasty, you should:

1. Be between the ages of 13 and 30
2. Have experienced patellar dislocation on multiple occasions
3. Not have arthritis
4. Have stopped growing