Page 396 - Canine Lameness

368 20 Hip Region

(A) (B)

(C) (D)

HIP REGION Figure 20.13 Images of different disease stages of avascular necrosis of the femoral head: (A) very early

changes showing a mild irregularity of the femoral neck (white arrow); (B) progression of the same changes
as noted in image A; (C) similar changes in a different patient affecting the femoral neck and head; (D)
severe changes associated with chronic avascular necrosis of the femoral head (white arrow), note that the
animal is also showing degenerative changes of the contralateral limb that are more consistent with
coxofemoral osteoarthritis.

of the contracture. Histologic evaluation shows normal muscle being replaced by a dense network
of collagenous connective tissue.
Unfortunately, to date no treatment for gracilis myopathy has been proven to be successful.
Various surgical methods of treatment have been attempted, but none have been shown to be suc-
cessful long term: Surgical resection of the muscle results in resolution of clinical signs for two to
three months, when symptoms recur (Lewis et al. 1997). Although gracilis myopathy may affect a
dog’s overall performance and the pathognomonic gait abnormality remains for the life of the
patient, it is not thought to be painful by their owners to the extent that patients can function well
enough to have good daily quality of life.

20.7.1.1 Signalment and History
This disease most commonly affects male German Shepherd Dogs between the ages of 3–7 years
but has been reported in Rottweilers and Doberman Pinchers as well (Steiss 2002). Dogs will pre-
sent with a unique and consistent gait abnormality. The gait comprises a shortened stride in the