Luxation of the patella is more known as "floating knee cap" resulting in the knee cap moving in and out of its current position. The knee cap sits in the cartilaginous groove at the end of the femur at the stifle. When this groove is shallow and
not deep the cap won't sit snuggly in its position and moves from side to side in either a medial or lateral position. Chihuahuas have a predisposition to this condition and although breeding healthy animals does not always guarantee the condition will
not develope over time, breeding healthy dogs will improve the outcome and severity of the luxation, breeding dogs with a very low risk and lower grading.
Patella luxation is graded from 1 to 4, 4 being the worse.
- GRADE 1: The
kneecap moves when manipulated, it returns to its normal position when not being manipulated and when the patient is standing normally. There is also no sign of lameness and the dog appears normal.
- GRADE 2: Same as grade
1 except that the kneecap does not move back to its normal position when the manipulator lets go. In some dogs the patella will move back into position when the animal moves. The dog will hold its leg or skip when its moves.
- GRADE 3: The
patella is out of place, dislocated, all the time but can be manipulated back into its normal position manually (though it will not stay there) Dogs with Grade 3 luxations may ‘skip’ like dogs with Grade 2 luxations, although more frequently. The
dog will show "weightbearing lameness" and will walk with a limp. Arthritis present.
- GRADE 4: This grade is more servere. Dogs with Grade 4 patellar luxations have significant deformities of the bones and other
components that comprise the stifle joint. The patella is not only out of place all the time but cannot even be manipulated back into place by the vet - even when under an anaesthetic. It is permanently stuck on the medial side. The dog
has extreme difficulty extending his leg when walking. Having a very unsturdy joint can lead to crutiate ligament injuries, so i would recommend that surgery is a must.
There are other factors to take into consideration when diagnosing the cause
of luxation in a dog. Puppies with poor breeding can develope the condition very early on, these pups should never be bred from. Jumping on and off couches, beds and stairs can cause damage to puppy knees when they are growing and can lead to patella luxation
in the dog further down the track. Carrying extra weight can cause patella issues in older or desexed animals as they tend to put on the weight. This causes presure on the joints and can result in luxating patellas. These are some causes that should be avoided
for the health of the animals.
For more comprehensive information on patella luxation please read the article provided