Morphological and functional evaluation of a dog with dimelia.

Weight bearing patterns were investigated on a young Cocker Spaniel with dimelia (mirror hand) of the left forelimb, using a pressure sensing walkway (PS walkway). The dog had two left forelimb paws, both originating from the carpus, with symmetrical duplication of metacarpal bones and phalanges. In addition, the left radial head was subluxated and asynchronous growth of the left radius and ulna was noted. The PS walkway demonstrated minimal weight-bearing of the extra (medial) paw and longer metacarpal pad contact of the affected limb. The radiographic changes and the weight-bearing pattern during gait suggested that more weight was loaded on the lateral paw of the affected limb. Treatment was not recommended because of the relatively good limb function and the absence of overt pain. This is the first reported case of canine dimelia and foot pressure patterns in a canine congenital musculoskeletal deformity.