This study was performed at The Cornell University Hospital for Animals
Original Article - Research
The S-Measurement in the Diagnosis of Canine Hip Dysplasia
Article first published online: 14 SEP 2011
© Copyright 2011 by The American College of Veterinary Surgeons
Volume 41, Issue 1, pages 78–85, January 2012
How to Cite
Ogden, D. M., Scrivani, P. V., Dykes, N., Lust, G., Friedenberg, S. G. and Todhunter, R. J. (2012), The S-Measurement in the Diagnosis of Canine Hip Dysplasia. Veterinary Surgery, 41: 78–85. doi: 10.1111/j.1532-950X.2011.00874.x
Funding for this study was provided by the Cornell University Veterinary School Dean's Fund for Clinical Excellence.
- Issue published online: 23 JAN 2012
- Article first published online: 14 SEP 2011
- Manuscript Accepted: JUL 2011
- Manuscript Received: AUG 2010
- Cornell University Veterinary School Dean's Fund
To propose a direct measure of subluxation of the femoral head (S) in the assessment of hip joint laxity and evaluate it for clinical use.
Method comparison study.
Dogs (n = 51).
Dogs were sedated or anesthetized for a dorsolateral subluxation (DLS) examination. Two sets of radiographs were acquired, 1 each by a different technologist. A calibrated measuring bar was included on the image at the height of the hip to assess magnification. The DLS was calculated for each hip and different persons unaware of these details measured the “S”-value. One person measured the S-value 3 times over 3 days. Box plots were used to determine a cut-off for the empiric (8 mm) and corrected (4 mm) S-value.
Of 51 dogs, 33 were dysplastic based on a DLS score <55%. Magnification and body weight were strongly correlated (r = 0.4922, P = .0006). Both empiric and corrected S measurements showed good agreement with the DLS score (κ = 0.688 and κ = 0.681, respectively). The corrected S measurement produced more false negatives. Bland–Altman analysis showed interobserver and technician variance acceptable for clinical use (limits of agreement < ±3 mm). Intraobserver repeatability was acceptable for the right hip (95% of differences were ≤1.3 mm and 100% ≤ 1.9) but not for the left hip.
Using a cut-off value of 5 mm, the empirical S measurement can be used to exclude hip dysplasia in young dogs of various body proportions.