Amber is a spayed female Australian shepherd, born in April, 1998. She was diagnosed with bilateral hip dysplasia a year later, in May, 2000. She had marked dorsal subluxation (partial dislocation) of the left hip, a positive Ortolani sign (indicating joint laxity), and crepitus ("crunching and grinding") when the left hip joint was palpated. The right hip dysplasia was not as severe as the left.

Figures 1& 2 . X-radiographs on 5/18/00 (left) and 5/24/00, showing no DAR on the left hip and poor DAR on the right hip.

Figures 1 and 2, both DAR views ("DAR" stands for Dorsal Acetabular Rim, the upper edge of the hip joint socket), show the severe lack of a DAR in the left hip and a relatively poor one for the right hip. The right femoral head (ball portion of the joint) was sitting in a shallow cup while the left femoral head was riding on a saucer.

A left "standard" DARthroplasty was performed on May 24, 2000. Two corticocancellous bone strips were used to create a new DAR (Figures 3 and 4). Figures 5 and 6 are close-ups of the immediate postoperative left hip, showing the "new DAR" created by the corticocancellous bone strip grafts. These bone grafts eventually anchor to the old DAR via drill holes in the old bone. The graft strips are held in place by sutures through the strips into the joint capsule. The joint capsule eventually becomes the new joint surface.

Figures 3 & 4. X-radiographs from a ventro-dorsal (left) and DAR aspect (right), showing new DAR created during the DARthroplasty on 5/24/00.
Figures 5 & 6. Close-up X-radiographs of new DAR.
Figures 7 & 8. Follow-up X-radiographs on 7/3/00, showing solidification and consolidation of the new DAR.

Our first set of follow-up radiographs were taken on July 3, 2000. At this time, Amber was walking very well on her left rear leg. She also demonstrated an excellent "sit" test. The sit test is an evaluation of how well the dog sits, with the hocks on the ground and the knees pointing straight forward, fully flexed (not extended out to the side, like dogs will sit when their knees or hips bother them).

Figures 7 and 8 show that the left femoral head has started to move slightly more under the old DAR and the new DAR graft is solidifying and consolidating, providing good new bony support for the left femoral head. The joint looks pretty quiet…that is, there is no evidence of any significant progression of degenerative arthritic changes.

Continued in Part 2.