There is talk of patella luxation in dogs when the patella, small bone located in front of the knee joint and the correct position is necessary for the proper functioning of the tip of the animal, is out of place, trochlea, causing pain and functional weakness in the dog.
Dislocations within the medial dislocation is the most common. Surge 80% of cases whereas the lateral is given only 20%. Between 30% and 50% of cases are bilateral and more common in females than in males, especially small breeds and toys.
The lateral dislocations can occur in adults and small breed puppies of large and giant breeds.
This pathology is characterized by a misalignment of the member, distortions are produced during the development of the animal, which makesthat the patella is out of place. It can be due to a congenital condition, or in some cases caused by trauma.
Ideally, dogs suffering from this congenital condition, not used in reproduction and is transmitted through the generations.
Some dogs have patellar dislocation caused by a trauma. In these cases usually the dislocation is associated with a tear of the anterior cruciate ligament of the knee.
Depending on the clinical symptoms and radiological findings subsequently, can berated dislocations in 4 grades:
DegreeI - Intermittent patellar luxation causing the limb lamenesswhen it is out of place. In the dynamic test,every three or four steps up the leg by flexing the knee or get a little hop.
Grade II- Dislocation that occurs more frequently than in Grade I. The kneecap dislocates easily. There is aslight external rotation of the leg. Many dogs live with this degree for years before manifest progressive arthritis and a limp orcauses moresevere.
Grade III and IV- The head is of formpermanently dislocated, with remarkable external rotation of the leg. There is moderate lameness. If bilateral, dogs walk with bowed legs, turning the foots inwards and bearing the weight on the forelimbs. Inmore severe cases may be confused with hip problems.
In addition, the animal shows pain, Crackles and increased sensitivity in the knee, leading it to decrease its activity, even refusing to go up and down stairs, car or sofa.
Treatment depends on the degree of dislocation and limping, but in most cases surgical treatment consisting in the repair of soft tissue, bone reconstruction or a combination of the two is required. There are endless techniques and orthopedic veterinarian or choose the most appropriate in each case.
Among the most commonly used techniques are: Overlay medial or lateral retinaculum, overlapping the fascia lata, antirotational suturing the patellar and tibial ligaments, desmotomy / capsulectom.a, quadriceps release, trochleoplasty (trochlear chondroplasty, sulcoplastia resection sulcoplastia trochlear), transposition of the tibial tuberosity, patellectomy, osteotomy ...
As novelty are applyingorthoses for knee dislocationas a means of orthopedic conservative treatment that maintains the patella in the femoral condyles and prevent pain and instability. Theseorthosesare custom made and are very useful in cases where surgery has failed, can not or do not want to trade it for different reasons.
Marta Subirats&Toni Ramon
Technical team Ortocanis