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Hip Dysplasia in Dogs, Signs, Diagnosis and Treatment

Hip dysplasia is a common developmental issue in large and giant breed dogs and, by some estimates, is the most common inherited disease seen in dogs. This condition often leads to osteoarthritis of the hip joints, a crippling and painful disease that can significantly impact a dog's quality of life. Additionally, it can be a financial and emotional burden for dog owners.

The disease affects both male and female dogs equally and has a global distribution. Any large or giant breed dog, including large-sized mixed breed dogs, can develop the disease. Although reported in smaller breed dogs, it is much less common.

Breeds most frequently affected include:

  • German Shepherd
  • Rottweiler
  • Golden Retriever
  • Saint Bernard
  • Labrador Retriever
  • Newfoundland

Hip dysplasia was first described in 1935 and has been the subject of intense investigation for decades. Dozens of studies have examined everything from the genetics underpinning the condition to treatments to preventive measures, and the data on this problem is extensive.

A Developmental Disease

Although hip dysplasia is a significant cause of osteoarthritis in older dogs, the disease begins in puppyhood. The underlying abnormality is the hip joint's laxity, resulting in instability. This instability, in turn, leads to the progressive degeneration of the joint and clinical signs of osteoarthritis. Puppies with a genetic predisposition are born with normal hips, but changes begin within a few weeks of birth. Sometimes, lameness and gait abnormalities start at three months, while other dogs may not exhibit signs for years.

Clinical Signs of Hip Dysplasia

The American College of Veterinary Surgeons divides hip dysplasia into two groups based on age. Group one consists of younger dogs that don't have arthritis but show clinical signs due to hip laxity. Group two consists of mature dogs with hip osteoarthritis secondary to hip dysplasia.

Signs in Either Group Can 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
  • History of progressive rear limb lameness
  • Lameness after exercise
  • Loss of muscle mass in one or both rear legs
  • Difficulty jumping or climbing stairs

It's not unusual for young dogs to exhibit signs of hip dysplasia and then seem to get better. Improvement can happen because the body produces fibrous tissue to stabilize the loose joint(s). About 30% of dogs will need additional treatment later in life, but many can do well for long periods without treatment.

Genetics Play a Significant Role in Hip Dysplasia

Many years ago, researchers recognized that dogs with hip dysplasia often passed on the disease to their puppies. The strong breed disposition suggested it was inherited. Breed groups have been instrumental in identifying individuals with poor hips and removing them from the breeding pool.

Advances in molecular biology have allowed scientists to delve more deeply into the genetics of dogs with hip dysplasia. Researchers worldwide are conducting dozens of studies to pinpoint the specific gene or genes responsible for the disease. The goal is to identify a genetic marker for the disease that researchers could use to screen dogs.

Recent work on German Shepherds by a team at the University of Helsinki suggests that multiple locations on different chromosomes might be involved in hip dysplasia. Interestingly, the group reported that osteoarthritis mapped to chromosome 1, but joint incongruity mapped to chromosomes 9 and 28. The team plans on looking at these regions more closely to find genetic variations that could eventually inform the development of a genetic test.

Other Factors

Although researchers have long recognized that hip dysplasia has a vital genetic component, genetics alone do not explain why some dogs develop hip dysplasia while others with a genetic predisposition do not.

Excessive Caloric Intake, Rapid Growth, and Heavy Exercise Are Risk Factors: These factors are associated with bone growth that outpaces the development of the soft tissue structures important for joint stabilization, leading to joint laxity. Controlling these external factors can influence whether hip dysplasia develops or not, or it can modulate the severity of signs.

Diagnosis – Clinical Signs and X-ray Evidence

Physical examination findings coupled with history can raise suspicion of hip dysplasia. X-rays are essential for confirming the diagnosis, particularly in older dogs. Particular types of X-rays can screen dogs for hip dysplasia. Many breed organizations worldwide have embraced these special tests to improve hip conformation and keep dogs with mediocre and poor hip quality out of the breeding pool.

Two of the most common advanced screening tests in the United States are the Orthopedic Foundation for Animals (OFA) and the PennHIP protocols. Both were developed to assess hip conformation and predict the likelihood of degenerative joint disease development later in life.

Critical Differences Between OFA and PennHIP:

  • Age of Screening: PennHIP can be done on dogs as young as four months old, whereas OFA screening requires dogs to be at least two years old.
  • Sedation: Most dogs do not need sedation for OFA, but PennHIP requires sedation.
  • Training: Any veterinarian can take the X-rays required for OFA certifications, but special training is necessary for PennHIP.
  • Predictive Accuracy: PennHIP is more accurate in predicting whether osteoarthritis will develop later in life. However, OFA certification remains one of the most common and accepted assessments of hip dysplasia in the United States.
  • Costs: PennHIP evaluation is more expensive than OFA at most hospitals that perform both procedures.

Regarding optimal testing procedures, each test has pros and cons, and it's essential to work with your veterinarian to determine which test (if any) is best for your pet. If you're considering getting a large or giant breed puppy, inquire with your breeder whether they performed any hip evaluations on the sire and dam. Europe and the United Kingdom use other testing schemes, and it's essential for pet parents considering obtaining a dog from outside the United States to familiarize themselves with these different types of testing.

Treatment of Hip Dysplasia

Although hip dysplasia is a progressive condition, many treatments are available to help dogs of all ages.

Non-Surgical Options:

  • Weight Management: Keeping the dog at a healthy weight reduces stress on the joints.
  • Exercise: Regular, low-impact exercise such as swimming or controlled walking helps maintain muscle strength without overstraining the hips.
  • Physical Therapy: Techniques like hydrotherapy, massages, and stretching exercises improve joint mobility and reduce pain.
  • Medications: NSAIDs, pain relievers, and joint supplements (glucosamine and chondroitin) to manage symptoms.
  • Lifestyle Adjustments: Providing soft bedding, ramps to avoid stairs, and avoiding slippery floors. Choose Orthopedic Beds instead of Soft Beds for your dog.

Surgical Options:

  • Triple Pelvic Osteotomy (TPO): This surgery is used in young dogs that have failed conservative therapy. It requires a skilled surgeon and has a high success rate, with 80-90% of cases regaining good or better function within three months.
  • Total Hip Replacement (THR): Used in dogs over 12 months, both young and old, with degenerated joint structures replaced with synthetic components. 90-95% of dogs with total hip replacement have excellent post-surgery function.
  • Femoral Head Ostectomy (FHO): Performed as a salvage procedure to alleviate painful rubbing within the hip joint by removing the top of the femur, used only as a last resort.

Other Treatment Strategies:

  • Maintaining a healthy, lean body weight to relieve joint stress is essential for any dog with hip dysplasia.
  • Studies have shown that physical therapy improves muscle strength and quality of life.
  • Acupuncture and acupressure as adjunctive therapy can also be beneficial.
  • Supplements, such as glucosamine and chondroitin, may benefit some dogs.
  • Omega-3 fatty acid supplementation.
  • An injectable antibody that blocks pain signal transmission.
  • Injectable medications that help replace joint fluid.
  • The icing of affected joints.
  • Massage.
  • Low-level heat therapy (thermotherapy).

Always consult with your veterinarian before starting any treatment program!

New Ideas for Diagnosis and Treatment

Researchers continue to look for better ways to treat the disease. Recent publications on novel therapeutics include:

  • Platelet-Rich Plasma: In conjunction with physical therapy, improved limb function in dogs with osteoarthritis caused by hip dysplasia.
  • Stem Cells with Hyaluronic Acid: Improved the range of motion in dogs with hip dysplasia.

These studies examined only a few dogs but noted no adverse effects. Further analysis with more dogs is needed to determine if these new therapies could benefit dogs with hip dysplasia.

Advances in Diagnosis:

  • While X-rays have been a mainstay of diagnosis for decades, they require trained professionals and can be expensive.
  • A new study from the University of Sarajevo reported biomarkers (molecules in the blood) that correlated with hip dysplasia compared to normal dogs. This finding suggests that researchers could develop a simple blood test to screen dogs for this disease, potentially offering a more cost-effective detection method.
  • The search for more genetic markers of disease continues. If found, a screening test to look for these markers could help dog breeders make more informed breeding choices to minimize disease risk.