Hip dysplasia is the abnormal growth/development of the hip joint. This abnormal development occurs early in life; however, pets may not show signs of discomfort until older in age.
The hip is a ball and socket joint. In hip dysplasia, the ball (femoral head) does not fit in the socket (acetabulum) well. Over time, the poor fit and looseness (laxity) leads to development of arthritis in the hip as the body tries to stabilize that joint. Depending on the severity of this "poor fit" determines treatment - either with medical management of surgical intervention.
It is a very common developmental problem, especially in larger dogs, although it can also be seen in small dogs and cats.
Hip dysplasia can become a crippling and painful disease that can significantly impact a dog's quality of life. In addition, the disease can be a financial and emotional burden for dog owners.
SIGNS OF HIP DYSPLASIA
Hip dysplasia almost always begins early in life. Puppies may have laxity in their hips that cause mild to severe signs or no signs at all. Signs in juvenile dogs (<18 mos of age) include:
- Bunny-hopping gait
- Rear-leg lameness (in one or both limbs)
- Difficulty rising
- Clicking sound from hips when moving or rising
- Weight shifting to front limbs
- Inability to exercise for long periods
It is common for puppies that show signs of hip dysplasia to "improve" for a period of time before the more severe signs become evident. This is a result of the body producing fibrous tissue to stabilize the loose joint.
The signs seen later in life (usually starting between 4-8 years of age) are a result of the arthritis and joint degeneration that develops over time. Signs of hip arthritis include:
- Difficulty/slowness getting up
- History of progressive rear limb lameness
- Lameness after exercise
- Loss of muscle mass in one or both rear legs
- Difficulty jumping or climbing stairs
Breeds most commonly affected include German Shepherd, Rottweiler, Golden Retriever, Saint Bernard, Labrador Retriever, and Newfoundland.
CAUSES OF HIP DYSPLASIA
- Genetics - Genetic inheritance of hip dysplasia is one of the primary causes. Therefore, any dog considered for breeding should be screened for hip dysplasia, do reduced the likelihood on passing hip dysplasia to the puppies.
- Environmental factors - In some dogs, controlling environmental factors can change the severity or onset of clinical signs.
- Excessive caloric intake (overfeeding) - Overfeeding can cause stress on developing joints leading to joint laxity. Therefore, puppies who are prone to hip dysplasia should be grown at a healthy weight.
- Excessive/high impact activity
- Inappropriate calcium supplementation - We recommend an appropriate balanced diet for puppies that are prone to hip dysplasia, and calcium supplementation can hinder balanced growth.
- Early spay/neuter may have some effect on bone growth and therefore on a dog's propensity to develop hip dysplasia. Some studies have shown that certain breeds of dogs may benefit from delayed spaying/neutering because of this effect. The link between early spay/neuter and hip dysplasia remains largely unknown and delaying sterilization can lead to other issues such as developing mammary tumors/unwanted pregnancy/roaming, etc.
DIAGNOSIS OF HIP DYSPLASIA
Hip dysplasia is diagnosed based on clinical signs and x-ray images. Sedation is almost always required to get useful x-ray images that show joint laxity.
Screening for hip dysplasia in young dogs is useful to determine the likelihood of a pet developing signs of arthritis as they age. There are two main organizations in the United States that do advanced screening tests:
- PennHIP - PennHIP is a system that takes x-ray images that determines the amount of laxity with the hip joint. It can be performed as early as 16 weeks of age and has been found to be a more accurate method in predicting whether or not arthritis will develop later in life.
- Orthopedic Foundation for Animals (OFA) - OFA is a screening method that takes x-ray images of the hips, and requires dogs to be at least 2 years old. Although helpful, OFA certification doesn't guarantee that a dog will not develop arthritis later in life, nor does it guarantee that the offspring will not develop arthritis as a result of hip dysplasia.
In older dogs, routine x-ray images are often enough to evaluate them for arthritis.
MEDICAL TREATMENT OPTIONS
The majority of dogs with hip dysplasia are medically managed. Treatment options include:
- Maintaining a healthy weight - this is by far the most important treatment available to patients with hip dysplasia. Excess weight puts excess stress on the joints and leads to further damage.
- Joint supplements - decrease inflammation and improve joint health
- UC-II Complex - Flexadin Advanced modifies the immune response that leads to arthritis buildup and can slow progression
- PSGAG (Adequan) can tighten ligaments and improve joint health slowing disease progression
- NSAIDs - these decrease inflammation which leads to pain (do NOT use human medication (eg. Aspirin, ibuprofen, etc), as they are not safe for use in pets)
- Pain medications
- PRP Joint Injections - Platelet Rich Plasma harvested from the dog's own blood and injected into the joint can control pain/joint inflammation for 3-6 months
- Stem Cell Therapy - stem cells injected into joints may develop into needed cartilage cells, suppress inflammation, and release proteins that slow down degeneration
- Alternative Therapies - Chiropractic, Acupuncture, and Laser therapy can all help control pain and improve quality of life
- Physical Therapy - healthy exercise is very important - it is critical to support weak joints with healthy and strong muscles.
SURGICAL TREATMENT OPTIONS
Surgery is sometimes indicated not only to help with pain management but also to improve hip mobility and function. The type of surgical procedure recommended depends on a dog's age and severity of signs.
- Juvenile Pelvic Symphysiodesis (JPS) - JPS is a surgery that closes a growth plate at the bottom of the pelvis, resulting in corrective growth of the pelvis as the puppy grows during the following 4-6 months. However, it can only be done for puppies between 8 to 20 weeks of age.
- Triple pelvic osteotomy (TPO) - This surgery involves cutting the pelvis around the acetabulum and placing a plate to reposition it to cover the femoral head better. It is used in young dogs that have failed conservative therapy.
- Total Hip Replacement - Typically performed in large and giant breeds and young dogs over 12 months of age. Similar to the procedure in people, degenerated joint structures are removed and replaced with synthetic components.
- Femoral Head Ostectomy (FHO) - a procedure where the ball of the femur is removed to alleviate painful bone on bone rubbing within the hip joint. Tissue fills in to create a false joint. The animal may not have a normal gait after this surgery, but it can allow them to move without the pain associated with severe arthritis. This surgery hinges on the animal having some muscle left and returning to significant activity once the post-operative healing period is over. It is critical that they build up muscle as quickly as possible post-op since that supports the joint after the femoral head is removed. FHO is ideally performed on dogs less than 80 pounds.