Disorder - Patellar luxation

Organ Systems Involved
Musculoskeletal

Alternative disorders described within LIDA

Hip dysplasia

Alternative Names
Medially luxating patella (MLP)

Presenting Signs

Patellar luxation in cats is usually congenital in nature (the condition is present at birth). It can cause varying degrees of lameness. A medially luxating patella is the most common type. This is when the patella, or knee cap, becomes dislocated toward the midline (i.e. inwards). The patella normally sits in a groove with two ridges either side of it to keep it in place. The groove is called the trochlea; the inside ridge is the medial trochlea ridge and the outside ridge is the lateral trochlea ridge. In cats with a medially luxating patella the medial trochlea ridge is smaller than usual and the trochlea is not as deep. This makes it easier for the patella to slide over the medial trochlea ridge and move out of its normal position.

Cats with patellar luxation can be continually lame or they may only be lame every now and again when the patella moves out of its normal position.

Cats at Risk

Cats with hip dysplasia. No sex or age predilections.

Breeds Affected
Abyssinian
Devon Rex


Treatment

Surgical correction of the abnormalities in the knee can be successful.

PubMed References
Patellar luxation

Contributor
Nicholas Cleland