Quinn MM, Keuler NS, Lu Y, Faria ML, Muir P, Markel MD.
Comparative Orthopaedic Research Laboratory, Department of Medical Sciences, School of Veterinary Medicine, Madison, WI 53706, USA.

Vet Surg. 2007 Jun;36(4):360-7. 

OBJECTIVE: To evaluate the accuracy of numerical rating (NRS) and visual analogue (VAS) scoring scales compared with force plate gait analysis and agreement between observers for each scoring scale.

STUDY DESIGN: Experimental study.

ANIMALS: Mixed breed dogs (n=21) with a right limb tibial osteotomy repaired with an external fixator.

METHODS: Three small-animal veterinarians with orthopedic training scored lameness using NRS and VAS before surgery, and at 4 and 8 weeks after surgery. Peak force and impulse were determined at the same time points using a force plate. Agreement between observers and with force plate data was assessed. Significance was set at P< or =.05.

RESULTS: Agreement was generally low among observers for both NRS and VAS scores. When evaluated at each time point, an acceptable level of agreement was present only at 4 weeks after surgery. Only impulse had a significant relationship with some of the observers' subjective scores. No significant relationships between any observer's scores and force plate data existed if very lame dogs were omitted.

CONCLUSIONS: Subjective scoring scales do not replace force plate gait analysis. Agreement is low unless lameness is severe, and each observer uses an individually unique scale. Subjective scoring scales most accurately reflect force plate gait analysis when lameness is severe.

CLINICAL RELEVANCE: Subjective lameness scoring scales may not accurately reflect lameness and do not replace force plate gait analysis. Observers must stay the same during the duration of a study for accurate analyses.