Influence of borderline hip dysplasia on joint kinematics of clinically sound Belgian Shepherd dogs.

OBJECTIVE: To detect changes in joint kinematics of clinically sound dogs with or without radiographically detectable borderline hip dysplasia (HD). ANIMALS: 20 Belgian Shepherd Dogs (Malinois; mean +/- SD age, 2.75 +/- 1.32 years) with no clinical signs of HD. PROCEDURES: Kinematic gait analysis was performed in Malinois walking on a treadmill. On the basis of results of radiographic examination for HD and in accordance with guidelines established by the Fédération Cynologique Internationale, dogs were assigned to group 1 (no radiographic signs of HD; 8 dogs) or group 2 (borderline HD; 12 dogs). Ground reaction forces and weight distribution among limbs and differences between groups were evaluated. Maximal sagittal angle during the stance and swing phases, the time at which they were detected, and angle velocities were calculated for joints of the hind limbs.
RESULTS: Ground reaction forces revealed no differences between groups. Dogs in group 1 had significant changes (earlier time for maximal flexion of the hip joint and less flexion and less range of motion of the stifle joint), compared with results for dogs in group 2. Maximal angle velocity of the stifle and tarsal joints was significantly lower during the swing phase in group 1 than in group 2. CONCLUSIONS AND CLINICAL RELEVANCE: This study revealed that dogs with borderline HD had altered joint kinematics. Our data provide basic kinematic values for clinically sound and affected dogs and can be used to investigate the long-term effects for subclinical radiographic changes of the hip joints of dogs.