Goniometry provides a simple and affordable way to obtain clinical measurements of joint range of motion. While the reliability and reproducibility of goniometry are well documented in humans and dogs, this method has not been validated for use in cats. Awareness of joint disease in cats has recently increased. Still, no validated, objective measures exist to quantify its severity and monitor its treatment in this species. To compare and validate goniometric joint measurements in cats, 20 orthopedically healthy cats had goniometric measurements of the carpus, elbow, shoulder, tarsus, stifle joint, and hip joints during flexion and extension, as well as the carpal and tarsal joints during varus and valgus angulation. Measurements were performed by a single investigator before and after sedation, and each series of measurements was repeated 4 times. Results from radiographic evaluation of the joints during extension and flexion were used as the gold standard for this study. A high degree of agreement was found between each series of measurements, and the measurements did not differ significantly by measurement type. However, the variability of measurements was greatest and outside acceptable limits for the carpal and tarsal measurements taken during varus and valgus angulation. It was concluded that goniometric measurements in cats are repeatable and valid, and that, subjectively, sedation helps to facilitate obtaining these measurements in cats without joint disease but does not alter the results.

COMMENTARY: A recent study found radiographic signs of osteoarthritis in 90 of 100 cats evaluated. However, despite the frequent nature of feline joint disease, clinical assessment of lameness and joint abnormalities in cats can be challenging. This article provides valuable information on the goniometric evaluation of feline joints. When used in conjunction with other techniques, including radiographs and arthrocentesis, goniometry can be very helpful in localizing the joint abnormality, assessing its severity, and in monitoring the success of various treatment protocols. The results of this study indicate that, for the most part, goniometric measurements in cats can be obtained with minimal variability (which is important if they are to be of value to the clinician) in orthopedically healthy cats. Success in obtaining valid goniometric measurements in cats with joint disease will probably depend on the patient's level of pain and the chronicity of the joint abnormality.

Validity of goniometric joint measurements in cats. Jaeger GH, Marcellin-Little DJ, DePuy V, Lascelles BDX. Am J Vet Res 68:822-826, 2007.