Patellar luxation is a record common condition observed in the miniature breeds of dogs such as shih-Tzu. In this disorder, one or both the knees can be affected in which the kneecap (patella) slips out of its actual position within the knee joint. Either it moves towards the inside of the knee named as medial patellar luxation (MPL) or outside of the knee & named as lateral patellar luxation (LPL). Dislocation of the patella towards inside is most common, whereas dislocation of the patella towards outside is observed often. Due to this condition the dog is unable to straighten out its leg & stands with its affected leg bent.
Two reasons why the Patellar luxation develops:
- Knee is not developed correctly.
- Injury to the joint.
The kneecap generally rests in & slides up and down within a groove at the end of the femur & actually the groove must be deep enough to avoid the patella from popping out on either sides. But due to the abnormal shallowness of the groove or if the joint has been damaged due to an injury, this allows the patella to move out of the groove on either side i.e. out or in while causing a leg lock, until patella returns back to its original position.
When the dog while walking, jogging or running unexpectedly holds up a rear leg for a few steps, screams out in pain & ultimately it straightens out its leg and keeps on walking or running as if nothing was wrong.
Patellar luxation as per the severity is divided into Four Grades.
- Grade 1: The kneecap can be managed manually i.e. pushed out of position but returns back to its original position (Surgery is not needed).
- Grade 2: The kneecap can spontaneously be pushed out of position and does not return back to its original position. (Minor surgery is needed).
- Grade 3: The kneecap is constantly dislocated & is possible to be pushed back into its original position but rapidly pops back out. (Surgery along with Tibial tuberosity transplant is needed).
- Grade 4: The kneecap is permanently dislocated & is not possible to be pushed back into its original position. (Surgery along with Tibial tuberosity transplant is needed).
Treatment for patellar luxation:
Patella luxation starts as Grade 1 or Grade 2 and degrades with time to a Grade 3 or 4. It causes pain to the dog. As the groove gets more shallow the dog becomes gradually more lame. So the Vet must be consulted at the very early stage of the condition i.e. Grade 1 or Grade 2, in order to prevent painful & long term arthritic crippling.
For Grade 1, as no surgery is required so the Vets prescribe
- Medications in order to decrease the pain, inflammation & to support cartilage heal.
- Thoroughly monitoring the dog not to let its condition get worse.
For Grade 2, The Vets prescribe same as for Grade 1.
For Grade 3, The Vets tell to go for surgery.
For Grade 4, The Vets tell to go for surgery.
The main end of all different surgical treatments is to let the patella function only in its original position.
Patellar Luxation is originally caused by the abnormal growth of the knee so in this precise matter it cannot be prevented. The only step you must take on encountering the first symptom of such problem is not to let your dog gain more weight as heavier body will increase stress on its knees.
It is not possible to prevent cases of patellar luxation that originate because of abnormal development of the knee. If you are picking out a puppy from an at-risk breed, it does not hurt to ask if any of the puppy’s relatives have symptoms of patellar luxation.
What does Patellar Luxation look like in dog ?
MPL in Dogs (Medial Patellar Luxation)