Sequential measurements of the tibial plateau angle in large-breed, growing dogs.
OBJECTIVE
To determine the earliest age that canine tibial plateau angles (TPAs) can be reliably measured and determine whether TPAs change during long bone growth.


METHODS
10 Labrador Retrievers and 20 Labrador Retriever-hound crossbreeds.


METHODS
Stifle joints were radiographed every 2 months from 8 weeks of age to radiographic closure of the tibial physes. Four examiners radiographically evaluated TPA, physeal closure status (ie, complete or incomplete) of the proximal and distal tibial physis, and whether anatomic TPA measurement landmarks were sufficiently visible (LSV) or insufficiently visible (LIV) for accurate measuring. Linear regression analysis was performed to detect change in TPAs over time. Mean ages with 95% confidence intervals (CIs) were determined for dogs with radiographs classified as LIV and LSV.


RESULTS
TPAs did not change from 90 days of age to physeal closure. Mean age for dogs with radiographs classified as LIV was 70.2 days (95% CI, 68.12 to 72.28 days), with no dog with LIV radiographs over 81 days of age. Mean age for dogs with radiographs classified as LSV was 85.5 days (CI, 76.73 to 94.27 days).


CONCLUSIONS
TPAs in Labrador Retrievers and Labrador Retriever-hound crossbreeds can be measured accurately after 90 days of age, and earlier attempts to measure result in falsely low TPA measurements. Measuring TPAs in growing dogs may allow earlier detection of premature physeal closures. As more is learned about the role of theTPA in cranial cruciate ligament injury, early treatment may be possible for growing dogs with cruciate ligament injuries and excessive tibial slope.
Odders
Jacob W
JW
Department of Small Animal Clinical Sciences, College of Veterinary Medicine, University of Minnesota, St Paul, MN 55108, USA.
Jessen
Carl R
CR
Lipowitz
Alan J
AJ
D000367:Age Factors; D000818:Animals; D001837:Body Weights and Measures; D004285:Dogs / Q000033:anatomy & histology* / Q000254:growth & development*; D008137:Longitudinal Studies; D011859:Radiography; D013264:Stifle / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D013977:Tibia / Q000033:anatomy & histology* / Q000000981:diagnostic imaging