Change of quadriceps angle after tibial tuberosity transposition in dogs with medical patellar luxation

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 ± 4.02 in grade 2, 26.08 ± 5.66 in grade 3 and 30.25 ± 7.41 in grade 4. The postoperative QA was 21.25 ± 3.24 in grade 2, 19.16 ± 3.92 in grade 3 and 19.72 ± 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.