Clean Run - March 2012 - 31

About About Hip Dysplasia
What is hip dysplasia?
Hip dysplasia (HD), in its classic sense, is osteoarthritis and degeneration of the hip joint. It is a developmental condition that can begin shortly after birth. The causes of hip dysplasia are many, but it is thought to be a heritable, polygenic disorder. Environment factors, such as early onset obesity and advanced age also contribute to the progression of disease.

Frequently Asked Questions

By Peter J. Lotsikas, DVM, Diplomate ACVS Photos courtesy of the author

Hip dysplasia is the most commonly diagnosed heritable orthopedic disease in dogs. On a yearly basis, dogs a ected with this condition comprise nearly 20% of my consultation caseload. I am o en asked the same questions repeatedly, and wanted to pass those questions (and the answers!) on to the readers of Clean Run. What might I see if my dog has a laxity issue?
Signs of laxity include tiring quickly after walks or play, hesitation to ascend stairs or jump into vehicles, and the classic gait abnormality termed “bunny hopping.” Lameness attributed to laxity usually manifests itself clinically between 6-12 months of age.

How is “laxity” diagnosed?
There are several ways to determine if laxity is present in the hips. One is simple palpation. A maneuver called the Ortolani test can be performed with the patient on his back or side. This maneuver involves attempting to push the femoral head from the acetabulum, and then allowing it to relocate itself back into place. The relocation is felt and/or heard as a distinct “clunk.” This test will be negative in a normal patient, meaning it cannot be displaced. If HD is suspected, radiographs are indicated. A standard view of the pelvis with the patient on their back is often referred to as the Orthopedic Foundation for Animals (OFA) view. This can be very helpful as a screening test. However, this view may not reveal dogs with more subtle laxity. A newer method of radiographic assessment, the PennHIP, allows for breed specific quantitative measurement of laxity, termed distraction index (DI). This radiographic method can be utilized for dogs as young as 16 weeks of age. The DI value will be predictive of the likelihood that a patient
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My veterinarian said my dog has “loose hips.” What does that mean?
Joint laxity, or “loose hips,” is one of the most significant predisposing factors for the development of osteoarthritis as an adult. The hip joint is comprised of a ball (femoral head) and socket (acetabulum). Laxity is defined as when less than 50% of the femoral head is seated into the acetabulum. It is caused either by poor conformation of the joint, or a stretched ligament of the femoral head. This condition can be persistent or intermittent, and vary in severity. Hip laxity will in turn promote the femoral head to “subluxate” in and out of the acetabulum as the patient ambulates, which can be uncomfortable. This abnormal motion can also lead to inappropriate wear of the femoral head and acetabular cartilage. It can also damage the ligament of the femoral head, which is the main ligament of the hip joint.
March 12 | Clean Run

Clean Run - March 2012

Table of Contents for the Digital Edition of Clean Run - March 2012