BVA Hip Score: Understanding Canine Hip Dysplasia Assessment and Management

What is BVA Hip Score?

The BVA Hip Score is a standardized, radiographic assessment method developed by the British Veterinary Association to evaluate the degree of hip dysplasia in dogs, providing a numerical score for each hip to guide breeding decisions and monitor breed health.

Understanding Hip Dysplasia

Hip dysplasia is a common skeletal condition that primarily affects large and giant breed dogs, but can occur in any breed, including humans. It is characterized by the abnormal development of the hip joint, leading to instability, pain, and eventually degenerative joint disease (osteoarthritis).

• Anatomy of the Hip Joint: The hip is a ball-and-socket joint, where the head of the femur (thigh bone) fits into the acetabulum (socket) of the pelvis. In a healthy hip, these structures fit snugly and move smoothly, lubricated by synovial fluid and supported by strong ligaments and muscles.
• What is Hip Dysplasia?: In hip dysplasia, the "ball" and "socket" do not fit or develop properly. The socket may be too shallow, the femoral head may be flattened, or the ligaments may be lax. This poor fit causes excessive movement within the joint, leading to wear and tear, inflammation, and the formation of osteophytes (bone spurs).
• Impact on Function: The instability and degenerative changes result in chronic pain, lameness (limping), difficulty rising, reluctance to exercise, and a reduced quality of life. While primarily genetic, environmental factors like rapid growth, excessive exercise in young animals, and nutrition can influence its expression.

The Role of the BVA Hip Score

The BVA/KC Hip Dysplasia Scheme was established in 1968 by the British Veterinary Association (BVA) in conjunction with The Kennel Club (KC) to help breeders reduce the incidence of hip dysplasia within dog breeds.

• Purpose of the Score: The primary purpose of the BVA Hip Score is to provide an objective, numerical assessment of a dog's hip conformation and the presence and severity of hip dysplasia. This information is crucial for breeders to make informed decisions, aiming to breed only from dogs with good hip scores to improve the overall health of future generations.
• Who is the BVA?: The British Veterinary Association is a professional body representing veterinary surgeons in the UK, dedicated to animal health and welfare. Their expertise ensures the scientific rigor and standardization of the scoring scheme.
• Why is it Important?: By systematically scoring breeding animals, the scheme helps identify those genetically predisposed to hip dysplasia. Over generations, this selective breeding can significantly reduce the prevalence and severity of the condition within a breed, leading to healthier, more functional dogs.

How the BVA Hip Score is Determined

The BVA Hip Score is determined through a standardized radiographic (X-ray) assessment of a dog's hips, conducted by a panel of expert veterinary radiologists.

• Radiographic Assessment:
  • The dog must be at least 12 months old (or older for certain giant breeds).
  • It must be permanently identified (microchip or tattoo).
  • The X-rays must be taken under sedation or general anesthesia to ensure proper positioning, which is critical for an accurate assessment.
  • A specific ventrodorsal extended view (dog on its back, hind legs extended straight back) is required.
• Scoring Criteria (9 Parameters): Each hip is assessed independently across nine specific anatomical features, with each feature given a score from 0 to 6 (0 being excellent, 6 being severely affected).
  1. Norberg Angle: Measures the laxity and congruity of the hip joint.
  2. Subluxation: Assesses the degree of displacement of the femoral head from the acetabulum.
  3. Cranial Acetabular Edge: Looks at the formation and integrity of the front edge of the socket.
  4. Dorsal Acetabular Edge: Examines the formation and integrity of the top edge of the socket, crucial for weight-bearing.
  5. Cranial Effective Acetabular Rim: Assesses the effective depth and coverage of the socket.
  6. Acetabular Fossa: Evaluates the central depression of the socket.
  7. Caudal Acetabular Edge: Examines the formation and integrity of the back edge of the socket.
  8. Femoral Head/Neck Exostosis: Checks for the presence of bone spurs (osteophytes) on the femoral head or neck, indicative of degenerative joint disease.
  9. Femoral Head Remodeling: Assesses changes in the shape and density of the femoral head, also indicative of degenerative changes.
• Scoring Scale: The scores for the nine parameters on each hip are summed, resulting in a total score for that hip. The lowest possible score for one hip is 0 (perfect) and the highest is 53 (very severe dysplasia). The two hip scores (left and right) are then added together to give a total hip score for the dog, ranging from 0 to 106.
• Interpretation: A lower total score indicates better hip conformation and a lower likelihood of hip dysplasia.

Interpreting BVA Hip Scores and Implications

Understanding the numerical score is crucial for its practical application in breeding and health management.

• What the Numbers Mean:
  • 0-8 (Excellent to Good): Hips are considered excellent with no or minimal evidence of dysplasia. These dogs are generally recommended for breeding from a hip health perspective.
  • 9-18 (Fair): Minor changes are present, but usually not clinically significant. Breeding decisions depend on breed mean and other factors.
  • 19-30 (Borderline to Mild Dysplasia): Definite signs of dysplasia are present. Breeding from such dogs is generally discouraged unless paired with a mate with excellent scores and careful consideration of the breed mean.
  • 31+ (Moderate to Severe Dysplasia): Significant hip dysplasia is present. These dogs should not be used for breeding.
• Breed Mean Scores: Each breed has a "breed mean score," which is the average hip score for all dogs of that breed that have been scored under the BVA scheme. It is important to compare an individual dog's score to its breed's mean. A dog with a score below the breed mean is considered to have better than average hips for that breed. The goal for breeders is to select animals with scores significantly lower than the breed mean.
• Breeding Recommendations: The BVA recommends that breeders select animals with hip scores well below the breed mean. Responsible breeding involves considering not only hip scores but also scores for other hereditary conditions, temperament, and overall health.
• Clinical Relevance: While primarily a breeding tool, an individual dog's BVA hip score can also provide insight into its risk of developing clinical signs of hip dysplasia. Dogs with higher scores are more likely to experience pain and lameness, requiring careful management throughout their lives.

Beyond the Score: Management and Prevention

While the BVA Hip Score is a vital tool for genetic improvement, managing hip health extends beyond just breeding decisions.

• For Affected Individuals:
  • Weight Management: Maintaining a healthy weight significantly reduces stress on the hip joints.
  • Controlled Exercise: Regular, moderate exercise (e.g., swimming, leash walks) helps maintain muscle mass and joint flexibility without excessive impact. High-impact activities or sudden movements should be avoided.
  • Nutritional Support: Joint supplements (e.g., glucosamine, chondroitin, omega-3 fatty acids) may help support cartilage health and reduce inflammation.
  • Medication: Non-steroidal anti-inflammatory drugs (NSAIDs) and other pain relievers can manage discomfort.
  • Physical Therapy: Rehabilitation exercises can improve strength, flexibility, and balance.
  • Surgical Options: In severe cases, surgical interventions such as triple pelvic osteotomy (TPO), femoral head ostectomy (FHO), or total hip replacement (THR) may be considered to improve joint function and reduce pain.
• Ethical Breeding Practices: Responsible breeders use the BVA scheme (and similar schemes for other conditions) to select breeding stock, prioritize health over aesthetics, and provide transparent information about their dogs' health clearances.
• Environmental Factors: Providing appropriate nutrition, avoiding excessive growth rates in puppies, and preventing repetitive high-impact activities during crucial developmental stages can help mitigate the expression of hip dysplasia, even in genetically predisposed individuals.

Conclusion

The BVA Hip Score is an indispensable tool in the fight against canine hip dysplasia. By providing a standardized, objective assessment of hip joint conformation, it empowers breeders to make informed decisions that contribute to the genetic health and welfare of dog breeds. For owners, understanding the principles behind hip health, whether for their pets or generally in biomechanics, underscores the complex interplay of genetics, anatomy, and environmental factors in maintaining musculoskeletal integrity.