Correlation of Optimal Tibial Plateau Angle with Patellar Tendon Angle on Tibial Plateau Leveling Osteotomy Surgery

The primary objective of this study was to identify the optimal corrected TPA (cTPA) that fulfills the objectives of both tibial tuberosity advancement, which adjusts the patellar tendon angle (PTA) to 90°, and tibial plateau leveling osteotomy (TPLO), which reduces the tibial plateau angle (TPA). In addition, the study aimed to determine whether the cTPA varies according to the sex, body weight, and age of dogs. Thirty-four dogs were included in this study, with 42 hind limbs analyzed. The PTA was measured from a lateral-view radiograph taken at a stifle angle of 135°, while the TPA was assessed using a stress-view radiograph. The mean TPA across the hind limbs was 28.7 ± 4.5°. No statistically significant difference in mean TPA was found based on sex, weight, or age. The mean cTPA value for hind limbs was 7.2 ± 3.9°. A significant difference was observed between the intact and the castrated male groups, with the mean cTPA being significantly higher in castrated males (p=0.014). A significant difference was found between the groups weighing 5 to 10 kg and those weighing ≥10 kg, with the 5 to 10 kg group exhibiting significantly higher cTPA values (p=0.028). No significant differences were identified among the groups classified by age. The cTPA value determined in this study, which satisfies the goals of TTA and TPLO surgeries, was 7.2°. However, obtaining the cTPA pre-operatively and on an individual basis is believed to yield theoretically optimal results.