Hip dysplasia is a condition that develops in dogs as they grow. It results in instability or a loose fit (laxity) of the hip joint. As the ball (the femoral head) continues to move in an abnormal manner, it deforms the socket (the acetabulum), wearing down the cartilage.
Over time the abnormal development and excessive laxity leads to scar tissue formation and bone spurs (osteophytes) around the joint. This is called Arthritis and can occur as early as 1-2yrs old if your dog has hip dysplasia.
It’s important to note that the amount of laxity of looseness in a hip joint is directly related to the chance that hip will develop Arthritis. The looser the hip, the greater the risk.
A joint that is the wrong shape or shallow will wear out faster than one that has a more normal shape.
The abnormal hip development can lead to hip pain, rear leg lameness, general difficulty moving, and poor posture.
- Hip Laxity
- Coxofemoral Laxity
- Subluxating Hips
- Femoral Head and Neck Excision
- Triple Pelvic Osteotomy
- Juvenile Pubic Symphysiodesis
- Total Hip Replacement
- Hip Arthritis
Hip dysplasia in dogs is primarily genetic and is more common in large and giant breed dogs. Examples of breeds more at risk of developing hip dysplasia include the Bulldog, Great Dane, Labrador Retriever, German Sherpard, and St Bernard.
The genetic predisposition can be increased by environmental factors in puppies, such as excessive growth and exercise, as well as your dog’s weight and nutritional intake (excess Calcium) through puppyhood.
Signs and Symptoms
- Hip pain
- Lameness (limping through one or both rear limbs)
- Bunny hopping gait
- Narrow stance
- Reluctance to rise the leg or jump
- Shifting of weight to the front limbs
- Loss of muscle mass on one or both of the rear limbs
- Audible click when walking
It’s important to note that there are hip dysplasia dogs with severe arthritis that run, jump, and play as if nothing is wrong and some dogs with barely any arthritic x-ray evidence that are severely lame.
By using specially positioned hip x-rays (PennHip and OFA) and physical examination your Vet can determine the presence of hip deformity and abnormal hip joint laxity.
While some tests are more accurate then others, they require sedation. For this reason many Vets do not favour the more accurate tests, and may even suggest that it would be best to have them done during other procedures that will already require your dog to be sedated.
If your dog is an at risk breed, the ideal time to examine them for pathologic hip laxity is when they are being desexed. The PennHip method can be performed from 16 weeks of age.
The PennHIP method is the most accurate x-ray method for detecting hip dysplasia and laxity in young puppies (from 16 weeks of age). It can accurately predict whether your puppy will develop hip Arthritis later in life, and what surgical options (if any) would be best suited for preventing future hip conditions.
The x-rays use a distraction index (DI) to measure the amount of hip laxity that is present when your puppy’s legs are placed in certain positions, and gauges how much of the ball is covered by the socket. This article gives further information on the DI.
The PennHip method generally defines a DI of ≥0.30 as “osteoarthritis susceptible,” and a DI of ≤0.30 as “osteoarthritis non susceptible.”
This method also requires your dog to be heavily sedated / anaesthetized in order to be able to effectively manipulate the hip joint. It is therefore more expensive than alternate diagnostic methods and comes with the complications associated with sedation.
Vets also have to undergo certification to be able to perform the PennHip evaluation. If you would like to undergo this evaluation and your Vet is not PennHip certified, you’ll need to source a PennHip certified Vet. They have to perform the special x-ray views, as well as the interpretation.
OFA Hip Score
A simpler option is the OFA (Orthopedic Foundation for Animals) method. This hip x-ray has been recognised by the AKC since the 1960’s.
The OFA method is a single extended hip view that assesses the current state of the hip joint. Your dog is assigned a “hip score”.
The OFA classifies hips into one of seven different “hip scores” from excellent to severely dysplastic. Read here for more information on the OFA hip scores.
The OFA method is more subjective, and therefore reliant on the individual experience of the Vet/s interpreting the images (requires three Vets to score).
OFA evaluation does not require heavy sedation or general anesthesia and requires only one x-ray view. It is therefore less expensive than the PennHip evaluation. It does not however, determine hip Arthritis susceptibility.
To read more about the PennHip and OFA hip dysplasia tests read here.
The Ortolani Sign is a physical palpation that has been used on newborn children since the mid 1930’s. It still remains the gold standard for detecting early onset hip dysplasia in newborns around the world.
Vets have been using the same test used on newborns, to detect the presence of laxity in puppies since the 1980’s. While it is not a definitive diagnosis, it can predict the likelihood of a puppy developing hip dysplasia within the first 1 or 2 years of it’s life.
Ideally the Ortolani test is performed during the puppy’s 10-16 week vaccination appointment. Some puppies may require a light sedative in order for the exam to be carried out. Others are happy enough to let the Vet perform the examination with little resistance.
Where To From Here?
Early diagnosis can be critical in hip dysplasia. If hip dysplasia is diagnosed before nine months of age then there are surgical options available that are no longer available much after this age.
While surgery may seem daunting, sooner or later, most dogs with hip dysplasia need surgery to build better support for the hip.
My next article on Hip Dysplasia in Dog’s will discuss the treatment options.