Evaluation of tibial torsion in Yorkshire Terriers with and without medial patellar luxation.

OBJECTIVE

To determine if medial patellar luxation (MPL) in Yorkshire Terriers is associated with tibial torsion.

STUDY

DESIGN

Prospective cross-sectional study.

ANIMALS: Yorkshire Terriers (n = 30; 60 tibiae).

METHODS

Each MPL was graded using a categorical grading scheme. Computed tomography of the tibiae was performed and tibial torsion angle (TTA) was assessed. MPL grade was analyzed with a general linear model where the independent variables include sex, neutering status, age, weight, and TTA.

RESULTS

Factors that had collective impact on MPL grade were TTA, age, and weight squared. As MPL grade increased, TTA decreased by 0.05° and age increased by 0.13 years. As weight increased, MPL decreased. There was no effect (P > .05) from scorers, side, and neutering status.

CONCLUSION

Body weight squared, TTA, and age affect MPL grade, suggesting that a torsional deformity may contribute to the development of MPL in Yorkshire terriers along with weight and age.