Vertical Patellar Position in Large-Breed Dogs with Clinically Normal Stifles and Large-Breed Dogs with Medial Patellar Luxation
Article first published online: 9 JAN 2006
Volume 35, Issue 1, pages 78–81, January 2006
How to Cite
JOHNSON, A. L., BROADDUS, K. D., HAUPTMAN, J. G., MARSH, S., MONSERE, J. and SEPULVEDA, G. (2006), Vertical Patellar Position in Large-Breed Dogs with Clinically Normal Stifles and Large-Breed Dogs with Medial Patellar Luxation. Veterinary Surgery, 35: 78–81. doi: 10.1111/j.1532-950X.2005.00115.x
- Issue published online: 9 JAN 2006
- Article first published online: 9 JAN 2006
- Submitted May 2005; Accepted August 2005
Objective— To further define vertical patellar position, as measured by the ratio of patellar ligament length to patellar length (L:P), in large-breed dogs with clinically normal stifles and compare that to the L:P of large-breed dogs with medial patellar luxation (MPL).
Study Design— Retrospective study.
Sample Population— Large-breed dogs (n=50) with clinically normal stifle joints and 30 large-breed dogs with MPL.
Methods— Large-breed dogs with clinically normal stifle joints or MPL were identified and divided into groups (NORM and MPL, respectively). L:P values were determined for each dog by 4 observers from single lateral stifle radiographs. L:P was compared between NORM and MPL groups and 95% confidence intervals (CIs) were calculated.
Results— All 4 observers found a significantly higher L:P (more proximally positioned patella) for the MPL group compared with the NORM group. Overall mean (±SEM) L:P were: NORM, 1.71±0.020 and MPL, 1.87±0.025. The 95% CI was determined to be 1.45–1.97 for the NORM group and 1.57–2.17 for the MPL group.
Conclusions— Large-breed dogs with MPL had a significantly more proximal vertical patellar position compared with large-breed dogs with clinically normal stifles. Large-breed dogs with L:P values >1.97 are considered to have patella alta.
Clinical Relevance— Proximal displacement of the patella within the femoral trochlear groove may play a role in MPL in large-breed dogs.