We evaluated the change of quadriceps angle (QA) after tibial tuberosity transposition. Twenty-nine animals and 37 limbs of the total 62 case possibilities qualified for this study. The preoperative QA was $24.02{pm}4.02$ in grade 2, $26.08{pm}5.66$ in grade 3 and $30.25{pm}7.41$ in grade 4. The postoperative QA was $21.25{pm}3.24$ in grade 2, $19.16{pm}3.92$ in grade 3 and $19.72{pm}7.30$ in grade 4. The postoperative QA for all grades significantly decreased when compared with the preoperative QA (P < 0.05). However, the postoperative QA values were not within the normal range, although the dogs' prognosis remained good during the 4-month follow-up period. These results suggest that postoperative QA outside of the normal range may be allowed clinically.

Keywords: patellar luxation, quadriceps angle, tibial tuberosity transposition, dog.