Display Settings:


Send to:

Choose Destination
See comment in PubMed Commons below
Vet Surg. 2012 Jan;41(1):78-85. doi: 10.1111/j.1532-950X.2011.00874.x. Epub 2011 Sep 14.

The S-measurement in the diagnosis of canine hip dysplasia.

Author information

  • 1Department of Veterinary Clinical Sciences, Louisiana State University, Baton Rouge, LA 70810, USA. dogden@vetmed.lsu.edu



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.

© Copyright 2011 by The American College of Veterinary Surgeons.

[PubMed - indexed for MEDLINE]
PubMed Commons home

PubMed Commons

How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for Blackwell Publishing
    Loading ...
    Write to the Help Desk