Radiographic Evaluation of Medial Patellar Luxation in Pomeranian Dogs by Measuring Quadriceps Angle (Q Angle) and Femoral Varus Angle (FVA).

Background: Patellar luxation is one of the common diseases in small breed dogs, especially Pomeranian dogs. This disease causes pain and lameness of hind-limbs the affected animal. Accurate diagnosis of this disease is of great importance in order to effectively intervene in it. Radiography is one of the simple yet accurate tools that help for evaluating and grading of this disease. The purpose of this study was to identify the size of the Quadriceps Angle (Q angle) and Femoral Varus Angle (FVA) in Pomeranian dogs with different grades of Medial Patellar Luxation (MPL). Materials and Methods: This study was conducted on Pomeranian dogs, whose MPL was clinically confirmed, and Putnam (1968) classification was used in its conduct. Each MPL, grade 1, grade 2, grade 3 and grade 4, 4 hind-limb from 11 Pomeranian dog were considered and two angles Q and FVA were measured in them. The Q angle is the result of the intersection of two lines, one of which connects the center of the patella bone to the tibial tuberosity and the other line that connects the anterior cruciate ligament to the center of the patella bone (Kaiser et al., 1997). The FVA angle is also the result of the intersection of two lines, one connecting the center of the patella to the proximal center of the femur, and the other one that connecting the center of the patella to the center of the tibia (Hauptman et al., 1985). In the process of studying the angles were measured and the average of each parameter was recorded separately for samples. Results: The results of this study showed that the mean Q angle in dogs with I, II, III and IV patellar luxation is 11, 16, 22 and 36 degrees, respectively. It was also found that the difference between the mean Q angle in different grades of luxation is statistically significant. The mean of FVA angle in dogs with I, II, III and IV patellar luxation were 28, 23, 22 and 16 degrees, respectively, These means were not statistically significantly different from each other. Conclusion: According to the findings of this study, measuring the Q angle and FVA angle can be helpful in prognosis of disease and degree of progressivity of luxation situation and changing the grade of disease in patient and making an acceptable descition for conservative or surgical treatments. [ABSTRACT FROM AUTHOR]