The aim of this study was to analyse the kinematics of the hindlimb and the activity pattern of the musculus biceps femoris, of the musculus quadriceps femoris and of the musculus gluteus medius in dogs with coxarthrosis to determine compensatory effects during walking. The results were compared with clinically sound dogs which have been investigated in a previous study. In this group of dogs a lameness has been excluded by a clinical examination and the evaluation of ground reaction forces. Light reflective spherical markers were placed on skin or a bandage over certain palpable bone points.
Surface electrodes were positioned on the shaved and cleaned skin over the selected muscles. EMG recording was done simultaneously with the measurement of the kinematics. The hip joint of the contralateral limb had a lower degree of extension, compared with the value for the clinically normal dogs. Maximal extension was detected earlier for both limbs of the lame dogs. The stifle joints showed an earlier time for the maximal extension for the lame dogs in comparison with clinically sound dogs. The tarsal joints had lower values for flexion and extension, and also the maximal extension and flexion were detected earlier compared with clinically sound dogs.
The musculus biceps femoris showed a maximal activity that took place later than it did in clinically sound dogs. The activity of musculus gluteus medius showed a higher range in dogs with coxarthrosis. Minimal activity was lower and maximal activity higher, while the activity in clinically sound dogs did not show such a high difference between the maximum and the minimum.
The results of the activity pattern of this study represents a database of muscle biomechanics in dogs with coxarthrosis. The aim was to describe the kinematics of dogs with a degenerative joint disease of the coxofemoral joint to get a better understanding of how these joints function. This work is a contribution to better understand the nature of coxarthrosis, and shall be an impulse to do more studies in this part of diagnostics, because there are less studies of use of electromyographie in dogs in general and of dogs with orthopedic diseases in particular.
dog / Surface electromyography / kinematics / coxarthrosis / walk