Hip Dysplasia

Most pet owner are aware of the term hip dysplasia but understanding the disease and it process, progression and treatment will better assist you in helping your dog. This very common degenerative joint disease can lead to tremendous discomfort for your dog.

What makes up the Hip?
It is first important to understand the structure and function of the hip joint. This joint is referred to as a “ball and socket joint.” The head of the femur serves as the “ball” and the “socket” located within the pelvis is referred to as the acetabulum. Both of these have cartilage surfaces which allows for a very smooth union. Besides the two bones there are other structures which hold the bone in place within the joint. There is a ligament at the top of the head of the femur which attaches it to the pelvis. There is also a joint capsule which surrounds this entire joint providing further stability. Outside all of this are four major muscle groups which help to hold everything in place. The sum and total of all the parts give comfort and stability to the hip.

What is hip dysplasia?
The term hip dysplasia referrs to instability within the hip joint. This instability can be congenital (born with) or acquired (due to a trauma). Though many times the puppy is born with normal hip congruity, as they grow the soft tissue structures that support the joint begin to develop abnormally. Therefore a laxity develops with the joint and head of the femur begins to separate from the acetabulum. It is this instability between the two bones which leads to major problems within the joint.

What causes hip dysplasia?
It is a widely accepted fact that there is a genetic component to hip dysplasia. If either of the parents has the disease then there is an increased risk for the offspring. Therefore it is important that you know the parents have been tested and certified with good hips. There are currently two certification organizations, 1) OFA (www.offa.org) and 2) PennHip (www.pennhip.org).

Studies have also shown a link between overnutirtion at a young age and hip dysplasia. This generally occurs with to rapid growth between the ages of three to ten months. Therefore overfeeding your puppy is discouraged. Consult with your veterinarian regarding proper feeding amounts.

We also know that being overweight can play a significant role is speeding the progression of degenerative joint disease. Obviously, if instablitiy exists in the joint then carrying around extra weight is only further going to place unnecessary stress on the already weak joint.

Lastly, over exercising at a young age can potentially greaten the risk. Primarily this refers to too much jumping which causes over extension of the hip joint. Though exercising is important to promote muscle development, like anything too much is not always good.

Predisposing Factors:

Reasons for Injury:

Understanding in Simple Terms:

             

Signs of Injury:

Diagnosis:

Diagnosis of ligament rupture should be split into two categories:

Non-Sedated Evaluation:

• It is important for your veterinarian to see your dog walking ie. Gate analysis.  Most of the time at this point your dog will either be not using the leg at all or just toe touching, but it is still important to evaluate.
• Another very good evaluation tool is asking your dog to sit.  Dogs that have injury to their cruciate ligament will always sit improperly with their knee off to the side and in slight flexion. 

 

Sedated Evaluation:

             

• The majority of the time it is necessary to sedate your dog for complete evaluation of the CCL ligament. It it is really important for them and the muscles surrounding/supporting the knee to be relax.  This way the joint can be properly evaluated. Remember this is a very complex joint, in which a number of different problems can arise.  There are number of very sensitive manipulations that your veterinarian will perform. 

• Crainal Tibial Trust “Drawer Sign”
• Using four designated points on the femur and tibia your veterinarian will attempt to slide the tibia forward.
• Tibial Tuberocity Advancement
• With the knee in slight flexion your veterinarian will flex the hock and therefore evaluate forward movement of the tibia in the area of the knee.
• X-rays of the knees for arthritic evaluation
• X-rays of the hips for potential underlying dysplasia

 

Surgery:

 

 

 

 

 

 

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