Fact Sheet

Toy, Miniature and Standard.

The kneecap luxates, or pops out of place, either in a medial or lateral position.  There are 4 grades of luxation, besides a dog that is “normal.”  The higher the grade, the greater the tendency to luxation and deformity.

Signs vary dramatically with the degree of luxation.  In grades 1 and 2, lameness is evident only when the patella is in the luxated position. The leg is carried with the stifle joint flexed but may be touched to the ground every third or fourth step at fast gaits. Grade 3 and 4 animals exhibit a crouching, bowlegged stance (genu varum) with the feet turned inward and with most of the weight transferred to the front legs.

Unknown, although familial tendency is suspected.  Patellar luxation may also be caused by a traumatic accident or abnormal structure.

The dog is examined awake (chemical restraint is not recommended) by palpation of the suspicious joint structure.

Varies.  Puppies as young as 8 weeks should be checked by a vet prior to being placed.

The kneecap should be returned to a normal position.  Surgery may be necessary in severe or chronic cases.

Every dog being used in a breeding program should be x-rayed or examined for luxation prior to being bred.  After one year old, the report should be sent to the Orthopedic Foundation for Animals for certification.  Only dogs that are normal should be considered for breeding.  Dogs that produce offspring with patellar luxation should be considered carriers.  Great care should be taken to avoid breeding carrier to carrier.

OFA: http://ofa.org/pl_overview.html