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The Importance of
Good Positioning on Canine Hip X-rays
The positioning is so bad in this x-ray that the dogs owner should have refused to pay for it.
The purpose of this article is to teach the average dog owner how to determine if a hip x-ray is done properly on their dog’s hips. The article will demonstrate correct positioning and poor positioning. It will show 2 different sets of x-rays done on the same dog on the same day. One set has good positioning, the second set has poor positioning. You will see that with poor positioning, a dogs hips can look worse than they actually are. You will also see that no matter what you do with positioning you can never make a bad hip into a good hip. The photo of the hip x-ray above (labeled good positioning) was done on a 10 month old German Shepherd from my kennel. While the dog is slightly angled on the x-ray plate, the positioning for the hips is pretty good. The photo below (the same photo as above) shows the various points on an x-ray to look at to determine if the dog was positioned properly.
Because this article is directed to the general public, I will not attempt to use the proper medical names for a lot of the terminology in this article. The first thing to look at in an x-ray is to see if the legs come straight down from the hips with the knee caps square and looking alike. We don't want to see one leg straight and the other going off at an angle. The above photo has 3 sets of colored arrows (green, yellow and red). The green arrows above point to the bone that the hip socket is built into. These bones almost look like wings. You will notice that you can see more of the wing on the right than the wing on the left. When the position is 100% perfect, both wings will look exactly alike. The yellow arrows point to holes in the bone structure. When the body positioning is correct the 2 holes on the left side are the same shape and size as the holes on the right side. The positioning is good on this dog, but not 100% perfect. That's why the holes on the right are slightly different than the left. This is most noticeable in the lower right hole being smaller than the left side lower hole. The red arrows above are the first things I look at when examining an x-ray. They point to the amount of pelvis bone that is covered by the leg bones on the x-ray. If you look at the pelvis, you can see that with the legs fully extended straight down, the legs overlay the very corners or tips of the pelvis. You can see the overlap through the leg bone. The picture above shows an even amount of overlap on both sides of the pelvis. The photo below shows a much larger overlap on the left of the screen than on the right of the screen. This is poor positioning.
The photo above is the same dog only a different x-ray than the first one. This second x-ray has poor positioning. Notice how much more the pelvic overlaps the leg bone (the green arrows) on the left than on the right. The result is the hip is pulled further out of the socket (the single red arrow) because of poor positioning.
The x-ray above is an example of poor positioning. Again this is the same dog as the good x-rays above. The dog is rotated. You can see the upper right hole through the body cavity is noticeably smaller on the right than the left. The pelvic wing under the leg is noticeably larger on the left than the right.
This photo graphically shows the results of poor positioning. This photo shows the same hip joint on the same dog x rayed on the same day. The hip in the red circle is a much deeper seated ball in the socket than the picture in the yellow box (which had poor positioning to produce this results). Some people ask how the difference can be so dramatic. My feeling is that these are young dogs. They have loose ligaments (just like a young child). If I took some of the falls that my eleven year old does I would have numerous broken bones. It’s the same with our dogs. As they get older their ligaments are not as loose and they will probably not stretch as much. There may not be as much of a difference in older dogs. But at a young age positioning is critical. The importance on positioning is often over looked by the vet that is shooting the films. There may be a number of reasons for this:
In my opinion, none of these are good reasons. To get good x-rays you have to have a good vet. I have a couple of local vets that are very good with x-rays. If they make a mistake they re shoot it at their expense. We just recently started to see the OFA send x-rays back to the vets because of poor positioning. When this starts to happen on a consistent basis, we will start to see much better x-rays of the dogs. Over the years I have seen some absolutely terrible jobs of x-raying dogs. As time goes by I will continue to add poor x-rays to this article so people can learn what to look for. There are several operations that are being done today to correct a bad hip and allow the dog to live a normal life. The x-ray below is an example of what a hip can look like after the operation. This operation needs to be done at an early age.
This is a photo of a very bad set of hips. It's questionable if surgery could even correct this dog’s problem. These are hips from an 8-month old German Shepherd that came from a back yard breeder. A dog with hips like this should be put down. It is facing a life of pain.
The 2 x-rays above are of the same dog (a Border Collie). The top x-ray was taken at 8 months of age. The lower x-ray was taken at 4 years of age. This can give you an idea of what will happen to bad hips over time. Notice the thickening of the neck of the joint. The ball also shows signs of arthritis. This dog is living as a house dog where her exercise is monitored. When the pain gets bad she is given Rymadil and this seems to make her comfortable. Same Dog 9 Months Apart Here are photos of 2 different x-rays taken of the same dog taken 9 montha apart. The first x-ray showed the dog having bad hips. If you look closely you will see the positioning is not correct. It's not that bad but it is also not perfect.
Taken Sept 2002 The second photo below shows the dog with good hips. The positioning has been improved and this has made a big difference in how the x-rays look.
Taken June 2003 My advice to anyone would be to not accpet incorrect positioning of any kind. Discuss this with the vet before the xray. Show him this article if he has anyquestions. I personally will not pay for a bad xray. I recently had a similar situation with a young dog that I xrayed at 6 months. The picture did not look that good but the rest of the litter was good. So I redid the xray at 9 months and saw an entirely different xray. The dog will pass OFA if the xray stays the same. I would also recommend swimming a dog to build muscle mass if there is any question on the hips. The better condition a dog is in the better chance of a good x-ray. I have a friend who has watched the OFA on a yearly basis. She has noticed that there are more bad hips in the winter months than summer months. For me this translates into dogs not being in as good physical condition in the winter months as the summer. In the future I will not be xraying dogs in the winter. I will also make sure that my dogs are in excellent condition when the xrays are taken.
The Following are 3 x-rays of the same dog done at different times.
January - 2003
Positioning still not correct - look at right hip
May 2003 Better but not perfect. Look at the right hip in all three shots.
This is the worst case of hip positioning that I have ever seen. The Vet that took them and gave them to the customer should get out of the business.
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