In the realm of canine hip evaluation, two prominent methods have emerged: the Orthopedic Foundation for Animals (OFA) hip scoring and the University of Pennsylvania Hip Improvement Program (PennHIP). While both aim to assess canine hip health, they employ contrasting approaches and methodologies. In this article, we delve into the differences between PennHIP and OFA, examining their respective strengths, limitations, and implications for canine orthopedic care.

Orthopedic Foundation for Animals (OFA):

Established in 1966, OFA has long been regarded as a standard method for evaluating canine hip health. The OFA hip scoring system relies on radiographic evaluation of hip conformation in mature dogs, typically at or after 24 months of age. A panel of veterinary radiologists assigns a numerical score ranging from excellent to dysplastic based on the appearance of the hip joint, including factors such as subluxation, joint congruity, and evidence of degenerative changes.

University of Pennsylvania Hip Improvement Program (PennHIP):

PennHIP represents a newer approach to canine hip evaluation, developed in the late 20th century by Dr. Gail Smith and colleagues at the University of Pennsylvania School of Veterinary Medicine. Unlike OFA, which assesses hip conformation in mature dogs, PennHIP focuses on evaluating hip joint laxity in puppies as young as 16 weeks old. The PennHIP procedure involves measuring the distraction index (DI), which quantifies hip joint laxity by assessing the degree of hip joint displacement under anesthesia. Additionally, PennHIP evaluates hip joint conformation and provides breed-specific data for comparison.

Key Differences:

• Age of Evaluation:

  • OFA: Typically evaluates mature dogs at or after 24 months of age.

  • PennHIP: Evaluates puppies as young as 16 weeks old, allowing for early detection of hip joint laxity.

• Methodology:

  • OFA: Relies on radiographic assessment of hip conformation and assigns a numerical score based on subjective interpretation.

  • PennHIP: Measures hip joint laxity using the DI technique, providing a quantitative assessment of hip joint stability.

• Predictive Value:

  • OFA: Provides a snapshot of hip conformation at a specific point in time but may not predict future development of hip dysplasia.

  • PennHIP: Offers valuable predictive information about a dog’s susceptibility to developing hip dysplasia later in life, aiding in breeding decisions and proactive management.

Implications for Canine Orthopedic Care:

• OFA remains a valuable tool for assessing hip conformation in mature dogs and is widely accepted within the veterinary community.

• PennHIP offers a proactive approach to identifying hip joint laxity in puppies, enabling breeders to make informed breeding decisions aimed at reducing the incidence of hip dysplasia.

• Integrating both OFA and PennHIP evaluations can provide comprehensive insight into a dog’s hip health, guiding breeding programs and informing orthopedic management strategies.

While OFA and PennHIP serve similar objectives – evaluating canine hip health – they employ distinct methodologies and target different stages of a dog’s life. Understanding the differences between these two approaches is crucial for veterinarians, breeders, and dog owners seeking to optimize orthopedic care and minimize the impact of hip dysplasia in canine populations.