Comparison of trot kinetics between dogs with stifle or hip arthrosis.

The purposes of this study were: 1) to describe and compare the trotting gait of normal and lame dogs secondary to stifle (GONOA) or hip (COXOA) osteoarthritis (OA) using multiple ground reaction forces (GRF) parameters, and 2) to pinpoint any characteristic in gait profile ('signatures') which could help to discriminate a lameness secondary to GONOA or COXOA. Fifty-one large breed dogs with OA (19 GONOA, 32 COXOA) and 22 normal dogs were included in the study. The vertical and cranio-caudal (braking-propelling) GRF were collected. The total stance time, and for each orthogonal vector, the peak force, impulse, time to peak, and the rate of limb loading were recorded. Vertical and craniocaudal forces were found to be significantly decreased in both OA groups compared to normal dogs. Vertical, cranial and caudal limb loading were also most often lower for both OA groups. In addition, the vertical and cranial forces were significantly lower in dogs with GONOA compared to COXOA and normal dogs. This study has demonstrated that, at a trotting gait, OA dogs secondary to GONOA and COXOA load their affected limb, brake and propel earlier during the stance phase, but generally with less magnitude than normal dogs. Dogs affected by GONOA also present more severe gait alterations than dogs with COXOA. The vertical and braking specific GRF alterations described may be kinetic 'signatures' linked more to lame dogs secondary to GONOA versus COXOA. Finally, this study has also provided useful baseline GRF data for further clinical and research investigations.