Dislocation of the patella is when the kneecap (patella) comes right out of the groove in the thighbone (femoral groove) in which it normally rides.
Page updated July 2023 by Dr Sheila Strover (Clinical Editor)
Patellar dislocation, where the patella has jumped completely out of the groove.
How common is patellar dislocation?
Dislocation of the patella is most common in young people (16-20 years) and most frequent in the female sex.
What allows the kneecap to dislocate?
Dislocation may follow a traumatic event, like a blow on the knee. Frequently, however, there is an underlying anatomical problem that predisposes the knee to patellar instability. Such anatomical problems include:
Consequences of MPFL tear after dislocation
It is common to tear the medial patellofemoral ligament (MPFL) during a dislocation event, which then makes it easier for the patella to dislocate again. Most early surgery would be focused on addressing this problem and reconstructing the ligament.
Relevant material -
2019 - All about dislocation of the patella - by Dr Sheila Strover (Clinical Editor)
Journal interpretation - 2023 - Framing Patellar Instability: From Diagnosis to the Treatment of the First Episode
- Authors: Maggioni DM et al. and summarised for readers by Dr Sheila Strover (Clinical Editor)
eBook - Factors contributing to an Unstable Patella
Easy to read ebook about kneecap dislocation. Free to download. Authored by Dr Sheila Strover (Clinical Editor)