| Canine hip dysplasia is a common developmental | | | | For purposes of determining if a dogs lameness is |
| disease which tends to occur in large breed dogs. | | | | due to hip dysplasia, the routine ventrodorsal hip |
| The disease usually occurs in both hind legs and is | | | | extended radiographs work well. It is always indicated |
| caused by both genetic and environmental factors. | | | | to take radiographs to verify that the dog has |
| The underlying condition is a laxity in the structures | | | | dysplasia, even if the symptoms all fit, because there |
| that hold the hip joint together. In this article, I will | | | | are many other diseases with similar symptoms such |
| discuss the clinical signs that dogs show with hip | | | | as cruciate disease, lumbosacral disease, and hock |
| dysplasia and how the diagnosis of hip dysplasia is | | | | OCD. These diseases can be treated and the dog |
| made. | | | | may return to normal function. Unfortunately, some |
| Dogs with hip dysplasia tend to present in one of | | | | dogs are assumed to have hip dysplasia when they |
| two ways, either as a young dog or as an older | | | | do not or they have hip dysplasia but it is one of |
| patient. The young dogs present typically between | | | | these other conditions that are really causing the pain |
| 5-10 months of age with signs of difficulty rising in | | | | but radiographs never get taken to prove one way |
| the hind legs especially after rest, reluctance to jump, | | | | or the other. |
| a bunny-hopping gait when running, exercise | | | | Another important consideration when it comes to |
| intolerance, and popping that can be heard or felt | | | | diagnosing hip dysplasia is that just because a young |
| around the hips when walking. When examined, these | | | | dogs hips show some signs of dysplasia does not |
| dogs tend to show pain when the hips are pulled | | | | guarantee that the dog will have problems with the |
| straight back and laxity in the hip joint can usually be | | | | disease. It has been shown in studies that there is |
| demonstrated by a procedure called an Ortaloni test. | | | | poor correlation between clinical signs and radiographic |
| This test involves partially luxating the joint manually | | | | findings. Meaning, many dogs can have significantly |
| then feeling it pop back into place again. Young dogs | | | | dysplastic hips on radiographs but show no clinical |
| present with pain because the structures that are | | | | signs related to it. This is important when trying to |
| holding the hip together are too loose and as the dog | | | | decide if treating a young dog with dysplasia is |
| bears weight on the leg, the two bones keep pulling | | | | appropriate. |
| apart from each other causing the ligaments and joint | | | | For purposes of screening breeding dogs to ensure |
| capsule to stretch and tear resulting in swelling within | | | | that they do not have hip dysplasia, other |
| the joint. | | | | radiographic tests have been developed which studies |
| Older dogs present usually after 8-10 years of age | | | | have shown to be more accurate in detecting hip |
| and show signs of difficulty rising in the hind legs, a | | | | dysplasia. These tests are necessary because you |
| stiff or stilted gait when walking, and muscle atrophy | | | | want to know that the breeding dogs have no signs |
| in the rear legs. On examination, they are painful | | | | of hip dysplasia at all. These tests include the |
| when the hind leg is pulled straight back and have a | | | | PennHIP (University of Pennsylvania Hip Improvement |
| decreased range of motion in the hip joint. Most older | | | | Program) technique and the dorsolateral subuluxation |
| dogs do not have a positive Ortaloni test since the | | | | score. Both of these techniques use distraction to |
| joint has developed scar tissue preventing this from | | | | determine the degree of laxity within the hips. The |
| happening. Older dogs present with pain in the hips | | | | other benefit of these tests is that they have been |
| because over time, the two bones pulling apart have | | | | shown to be accurate as early as 4 months of age. |
| resulted in loss of the cartilage on the bone surface | | | | Other tests such as CT scans and MRI of the hips |
| and progressive arthritis formation within the joint. | | | | have been looked at in research settings but are |
| These dogs are said to have end-stage osteoarthritis | | | | rarely used in clinical practice. |
| within the joints. | | | | Screening breeding dogs for hip dysplasia before |
| Diagnosis of hip dysplasia is usually made with | | | | mating is important but does not guarantee that the |
| radiographs. Typically, a ventrodorsal hip extended | | | | puppies will not have hip dysplasia. Some dogs may |
| view is taken which is done by laying the dog on | | | | be carriers for the genes for hip dysplasia but not |
| their back and pulling both hind legs straight back. In | | | | show overt signs of the disease. When two dogs |
| the young dog, the main sign seen on the radiograph | | | | that are carriers are bred, they can have a litter of |
| is separation of the head of the femur from the | | | | puppies that have overt signs of hip dysplasia. The |
| acetabulum. Occasionally early bone formation within | | | | only current way to reduce this possibility is by |
| the joint, termed osteophytosis, may also be seen. | | | | screening not only the parents but all offspring for |
| The older the dog gets with this disease, the more | | | | multiple generations proving that none of the |
| bone change or remodeling, will be seen. Typically the | | | | generations of puppies ever showed overt signs of |
| femoral head changes from being round to flattened | | | | hip dysplasia which is rarely, if ever done. In the near |
| and the acetabulum becomes more shallow. Visible | | | | future, genetic analysis for hip dysplasia should be |
| new bone formation within the joint, termed | | | | available which will be a much easier and accurate |
| osteophytes, will be seen on the acetabulum and on | | | | way of screening potential breeding dogs. |
| the head of the femur also. | | | | |