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Case studies

Dr. Davis' research results.

After analyzing the data I had received from my survey, I concentrated my first case study on the group of dogs that had received failing grades with subluxation (the ball not being deep enough in the hip socket) as the only reason. Some of these dogs had one-sided (unilateral) subluxation while others had two-sided (bilateral).

As you can see from the table below of data compiled from my survey, when the only comment was failing because of subluxation- unilateral or bilateral- I achieved a 92% passing rate when I retook and resubmitted the dog’s x-rays. The tattoo or microchip number was verified each time to ensure it was the same dog being x-rayed.



Previous Grade

New Grade

Grades Changed

1 Golden Retriever borderline good +2
  "    " (same dog) fair   +1
3 Golden Retriever mild dysplasia good +3
4 Golden Retriever mild dysplasia good +3
5 Labrador Retriever mild dysplasia fair +2
8 Labrador Retriever mild dysplasia good +3
14 Shetland Sheepdog (fail) fair +1 (at least)
16 Rottweiler (fail) fair +1 (at least)
23 Golden Retriever (fail) fair +1 (at least)
24 Labrador Retriever * good +2 (at least)
25 Rottweiler moderate dysplasia mild dysplasia +1
26 Standard Schnauzer mild dysplasia good +3
28 Bernese Mountain Dog * fair +1 (at least)
29 Golden Retriever mild dysplasia fair +2
31 Golden Retriever mild dysplasia fair +2
32 Golden Retriever moderate dysplasia good +4
34 Golden Retriever moderate dysplasia mild dysplasia +1
35 Golden Retriever borderline good +2
37 Golden Retriever borderline good +2
39 English Springer Spaniel mild dysplasia excellent +4
40 Golden Retriever * fair +1 (at least)
43 Bullmastiff mild dysplasia fair +2
44 Golden Retriever mild dysplasia good +3
46 Golden Retriever mild dysplasia good +3
49 Afghan Hound mild dysplasia fair +2
50 Rottweiler mild dysplasia fair +2
52 Labrador Retriever mild dysplasia good +3
53 German Shepherd mild dysplasia fair +2


How, then, can this change in grade happen?

x-raysAs an example, look at the following radiograph brought to me by an owner.

This x-ray was taken by another veterinarian and submitted to O.F.A. for evaluation.  The film was accepted by O.F.A. and received a grade of mild dysplasia.  Notice how the long bones (femurs) are not parallel, the kneecaps (patella) are rotated to the outside and one side of the pelvic opening is larger than the other (the pelvis is tilted).

Now, look at the x-ray I did.  This film was also submitted to O.F.A. and received a grade of good.  Notice the difference in the appearance of the hips from the first film to the second.  It’s the same dog but different positioning.  In the second film, the femurs are nearly parallel and the patella is rotated inward and centered. Just by changing how the dog was positioned, the O.F.A. grade improved from mild to good.

x-rays2Which of these films most closely matches the recommendations for positioning as set forth by O.F.A. on their website here and here?

To read the full text of my study about the variation in O.F.A. grades in dogs with unilateral or bilateral subluxation only, click here.

To read a second study I did based on this survey which compares O.F.A. grades received when a dog is radiographed awake, sedated, or anesthetized, click here.

Case studies

Troy Animal Hospital