Summary
Objective 1) To provide specific quantitative data of tibial conformation in Labrador Retrievers
and Yorkshire Terriers; 2) To compare the tibial conformation of these two breeds;
and 3) To compare these data with previously reported data.
Methods Mediolateral radiographs of the stifle were obtained from 30 consecutive Labrador
Retrievers and 30 consecutive Yorkshire Terriers with an angle of extension of 135°.
The tibial plateau angle (TPA), the angle between the tibial plateau and the patellar
tendon (PTA), the Z angle, the distal tibial axis/proximal tibial axis angle (DPA),
and the relative tibial tuberosity width (rTTW) were measured and compared among the
two breeds.
Results The breed had a significant effect on all of the measured variables (p <0.01): Labrador
Retrievers had a lower TPA (25 ± 3° compared to 30 ± 4°), a lower Z angle (58.8 ±
3.2° compared to 69.2 ± 4.5°), a lower DPA (4.5 ± 2.3° compared to 10.8 ± 4.3°), and
a lower rTTW (0.74 ± 0.1 compared to 0.86 ± 0.1) than Yorkshire Terriers. The PTA
was greater in Labrador Retrievers compared to Yorkshire Terriers (106.9 ± 3.9° compared
to 103.7 ± 6.5°). Four correlations were found to be significant: the DPA angle was
correlated with the TPA, the Z angle, and the rTTW. The TPA was also correlated with
the Z angle.
Clinical significance Clinical significance: The variation in tibial conformation between breeds should
be taken into account when studying the role of each measured parameter in the pathology
of cruciate disease. When the relevance of each of the aforementioned measured parameters
is better understood, it may help determine the most appropriate surgical treatment.
Keywords
Tibia - stifle - cranial cruciate ligament - Yorkshire - Terrier - Labrador Retriever