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Patellar Dislocation & Instability (Unstable Kneecap)

Patellar Dislocation & Instability (Unstable Kneecap)


Your kneecap (patella) is usually resting in a groove at the end of the thighbone (femur). When the knee bends and straightens, the patella moves straight up and down within the groove, similarly to a train running on a track. Sometimes, the patella slides too far to one side or the other. When this occurs, the patella can completely or partially dislocate.

When the patella slips out of place, whether a partial or complete dislocation, it typically causes pain and difficulty moving the knee. Even if the kneecap goes back into place by itself, it will still require treatment to relieve painful symptoms.

Be sure to go to the doctor for a full examination, and be referred to an Orthopaedic Surgeon to identify any damage to the knee joint and surrounding soft tissues.  Patella dislocations can commonly cause fractures and loose bodies within the knee joint which may require removal.

Unfortunately patella dislocations may recur in up to 40% of cases.  It is very important to be investigated and managed appropriately to evaluate the cause of the dislocation and the best way to prevent it recurring.

Trochlea chondral lesion
(Above) Blue arrow indicates an area of cartilage damage.  Green arrow indicates normal cartilage on the underside of the patella.
Patellar Dislocation
(Left) The patella normally rests in a groove at the end of the femur called the trochlear groove. (Right) As you bend and straighten your knee, the patella slides up and down within the groove.
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03 5752 5020 mobile
We aim to see all fractures within 24hrs