**Acknowledgements**

As mentioned in the literature [21], severe skeletal changes associated with unilateral patellar aplasia were observed in one cat (**Figure 7A, B**), whose two brothers also had grade III patella

The re-luxation rate observed in this study (12.9%) is within the range reported by Arthurs and Langlay-Hobbs [35] and Wandgee et al. [35], although rates up to 50% have been reported [36]. Arthurs and Langley-Hobbs [35] report a greater frequency of major and patellar re-luxation complications in dogs weighing 20 kg or more compared to smaller dogs. In this study, two (6.6%) re-luxations were observed among the 30 dogs that weighed more

Recurrence of patellar luxation is a common complication associated with surgery; among the factors that contribute to re-dislocation are the severity of the lesions, because grade III and IV luxations indicate poor shaft alignment, failure to align the tuberosity of the tibia with trochlea, and contracture of soft tissues caudal to the joint, affecting the post-operative joint range of motion [6, 8]. As with the loss of convexity of the patella, it loses its slot in the femoral trochlea. Daems et al. [31] postulate that one of the reasons for surgical failure in stable post-surgical patellae is the presence of cartilage erosion. Mostafa et al. [14] proposed that the proximodistal malalignment of the patella (patella alta and baja) influenced re-luxation. Patella alta is defined as the proximal displacement of the patella within the femoral trochlear groove. It has been speculated that patella alta may play a role in canine patellar luxation [12, 37]. The position of the patella in the trochlea, as Mostafa et al. [14] observed, might be the reason for one case of patellar re-luxation in our study. One dog weighing more than 20 kg with recurrent grade II bilateral medial luxation was evaluated. To assess the patellar position on the femoral trochlea, radiographic evaluation was performed according to the method described by Mostafa et al. [13]. After osteotomy of the tibial tuberosity, as described by Johnson et al. [37] and distally

We found no instance of implant failure among animals weighing at least 15 kg because the

The treatment was challenging in both cats with severe deformities of the distal femur, tibia and tail. It was not possible to correct all deformities, but there was improvement in ambulation. Although they were able to move around the house, as related by Hubler et al. [38], the

Post-operative measures, such as activity restriction and physical therapy, contribute to the success of treatment and might prevent some post-operative complications and favour an early

Based on these results, we conclude that patellar luxation should undergo surgical repair even when the clinical signs of disease are mild or absent, because this condition triggers patellar and extra-patellar changes that result in a more difficult surgery and promote the

luxation and no tail. The litter was a result of crosses between brothers.

174 Canine Medicine - Recent Topics and Advanced Research

transposing 0.5 cm the tibial tubercle, the patella remained in the groove.

recovery of muscle mass and the functional performance of the limb.

implants used were compatible with the dogs' weights.

gait abnormalities were extremely severe.

**10. Conclusion**

than 20 kg.

We thank Dr. Oscar Henriques Rocha Ladeira for conducting the photographs.
