Interobserver Validation of a Stifle Function Score in Dogs

Background: Cranial cruciate ligament rupture (CCLR) is common. Monitoring progress is based on subjective measures. We developed a stifle function score (SFS), and single observer scores had a significant correlation with ground reaction forces (GFRs). It is necessary to have an interobserver agreement using the SFS. The purpose of this study was to assess the agreement of independent observers of the SFS in dogs with CCLR compared to symmetry indices (SI). We hypothesized that the SFS would have a significant correlation with SI.

Materials and Methods: Study inclusion criteria were 10 to 50 kg, ages 1 to 12 years, no systemic illness, and unilateral CCLR. Exclusion criteria included body condition score greater than 7/9, other lameness, or neurologic abnormalities. SIs were determined at a walk using a pressure-sensitive mat. Three observers determined SFS. Regression analysis of SFS with SI was determined for each evaluator. SFSs from evaluators assessing the same dogs were compared using ANOVA. Comparisons between each evaluator were made using paired t-tests.

Results: Forty-four dogs were evaluated (evaluators: 1 n = 40, 2 = 44, and 3 = 26). All evaluators scored 11 dogs. There were NSD in SFS among evaluators (p > 0.05). Each evaluator’s SFSs had a significant correlation with SIs, with r ² of 0.67, 0.62, and 0.56 (p < 0.01).

Conclusion: We accept our hypothesis of good agreement among evaluators when using SFS to evaluate stifle function compared to objective SI of limb function. The SFS may be used by multiple evaluators to monitor progress in dogs following CCLR based on the interobserver evaluation of SFS compared with SI among different evaluators.

Publication History

Article published online:
12 September 2025