Patella luxation is a condition that causes the knee cap to pop out from its groove on the femur. It is a common condition and its seen more readily in small dogs where the knee cap tends to luxate medially. In large dogs the knee cap tends to luxate laterally. This condition is related to the alignment of the bones and muscles in the hind limb.
W a Shih Tzu dog 3 years of age came for a consult at the surgical department. He never walked to well on his hind limbs and his hips were far from good but lately he started to feel very sore on his hind limbs and he was unable to do much. After a detailed orthopaedic examination we had to agree with the owner that indeed he was not to comfortable, his hips were not great and he also had a bilateral patellar problem, the only issue was that W liked to stand out of the crowd and his knee caps were luxating laterally and not medially.
We immediately decided on a plan. X-rays were taken of the hips and stifles. The hip dysplasia was confirmed and classed as moderate to severe, the stifles looked like having degenerative joint disease on top of the patella luxation. We decided to repair the patella luxations in a staged fashion and the leg causing more grief was done first. The groove on the femur was depend and the tibial crest was transposed so that the knee cap will stay in. We also tightened the joint capsule and released a bit the muscle.
After his patella lunation surgeries W still walks with an abnormal gait but he is in no discomfort. As such we decided to continue with the conservative treatment for the hips at this point.