Patellar dislocation

Patellar dislocation is a painful and distressing event, when the patella jumps clean out of the restraining walls of the groove in which it normally rides.

dislocation of the patella with torn MPFL
In the first dislocation event the patella usually dislocates to the lateral side. This is due to the anatomy of the region. At the same time other structures may be injured, such as the medial patellofemoral ligament which may be torn and there may also be a small fracture on the medial side of the patellar and some associated bone bruising.

 

Management of patellar dislocation

A first event may be managed conservatively, with a period of immobilisation, after which sports may be limited for some months. If there is a subsequent event, the patient is usually subjected to a full investigation of any underlying causes and surgery may be planned. This may include a reconstruction of the MPFL. In patients where there is a marked problem with the anatomy, such as trochlear dysplasia, corrective surgery may be undertaken.

Synonyms: 
kneecap dislocation
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Related Content

All about dislocation of the patella

A discussion of key concerns about dislocation of the patella.

2017 - Primary patellar dislocations without surgical stabilization or recurrence: how well are these patients really doing?

Interpretation by the Editor of a 2017 published medical paper studying long term problems in patients whose original patellar dislocations were not surgically managed.

2017 - High incidence of acute and recurrent patellar dislocations: a retrospective nationwide epidemiological study

This is the Editor's interpretation of a paper published in the orthopaedic literature in 2017.

2016 - First time patellar dislocation in children – risk factors

This is the Editor's interpretation of a paper published in the orthopaedic literature in 2016.

Patellar Instability – a Continuum

An overview by Dr Lars Blond.

2012 - Primary traumatic patellar dislocation

Easy-to-read interpretation of a 2012 medical article on primary traumatic patellar dislocation.

Patellar instability and dislocation

Discussing how the anatomy can affect the tendency to dislocate the patella.

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FORUM DISCUSSIONS

Dislocated my patella 4 weeks ago.

Patella dislocation - what to expect and return to work

Bad kneecap dislocation - how long till knee recovers?

CLINICAL PUBLICATIONS

Primary traumatic patellar dislocation. Tsai C-H, Hsu C-J, Hung C-H and Hsu H-C. J Orthop Surg Res. 2012; 7: 21.

Medial marginal fracture of the patella following patellar dislocation. Toritsuka Y, Horibe S, Hiro-Oka A, Mitsuoka T and Nakamura N. Knee. 2007 Dec;14(6):429-33. Epub 2007 Sep 19.

Femoral avulsion of the medial patellofemoral ligament after primary traumatic patellar dislocation predicts subsequent instability in men: a mean 7-year nonoperative follow-up study. Sillanpää PJ, Peltola E, Mattila VM, Kiuru M, Visuri T and Pihlajamäki H. Am J Sports Med. 2009 Aug;37(8):1513-21. doi: 10.1177/0363546509333010. Epub 2009 Apr 17.

See also -

eBook - Factors contributing to an Unstable Patella