Breeder Health Guide

Hip Health Matters: Understanding PennHIP and OFA Testing

How each hip screening method works, what the results mean, and how to choose the right test for your breeding program.

Canine hip dysplasia (CHD) is one of the most common inherited orthopedic conditions in dogs. It can lead to pain, lameness and osteoarthritis. Because it is partly genetic, the choices breeders make about which dogs to breed shape the next generation.

Hip screening gives you objective information to guide those choices. The two most widely used methods are OFA and PennHIP. Each has its own strengths, and many serious breeding programs use both.

OFA Hip Evaluation

The Orthopedic Foundation for Animals (OFA) runs the best-known hip registry. Many breed clubs and buyers ask for it by name.

How it works

Your veterinarian takes a single standard radiograph with the hips extended. Three board-certified veterinary radiologists independently assess it, and their consensus becomes the final grade.

The grading scale

• Normal: Excellent, Good, Fair
• Borderline: a recheck is usually recommended in about six months
• Dysplastic: Mild, Moderate, Severe

Key features and benefits

• Widely recognized. Many breed clubs, kennel clubs and the CHIC health program reference OFA results.
• Public database. Passing results are searchable online, so you can research pedigrees before choosing a stud or planning a litter.
• Accessible. Any veterinarian can take the radiograph, and sedation isn't always required.
• Preliminary options. Young dogs can have preliminary evaluations. Official certification requires the dog to be at least 24 months old.

PennHIP Evaluation

PennHIP was developed at the University of Pennsylvania. It measures hip joint laxity, or how loose the ball sits in the socket. Laxity is a major risk factor for osteoarthritis later in life.

How it works

A PennHIP-certified veterinarian takes three radiographs with the dog under sedation or anesthesia:

1. Distraction view: gently displaces the femoral heads to reveal maximum laxity
2. Compression view: shows how well the ball fits the socket when fully seated
3. Hip-extended view: the traditional view, used to check for existing arthritis

The results

• Distraction Index (DI): a number from 0 to 1. Lower means tighter hips.
• Breed percentile: shows where your dog ranks against others of the same breed.
• Radiographic findings: notes any signs of existing degenerative joint disease.

Key features and benefits

• Early answers. Dogs can be evaluated as young as 16 weeks, before you invest years in training and showing.
• Objective and measurable. The DI is a measurement rather than a subjective grade.
• Strong predictor of arthritis risk. PennHIP laxity correlates well with later osteoarthritis.
• No selection bias. All PennHIP studies must be submitted, including poor ones, so breed data reflects the whole population.

Side by Side: The Key Differences

Which Test Is Right for Your Program?

There isn't a single right answer. Here's how many breeders use them:

• Choose PennHIP for early, objective data on young prospects, or to steadily improve hip tightness across generations using breed percentiles.
• Choose OFA when your breed club, CHIC requirements or puppy buyers expect an OFA rating, or you want your dog in the public database.
• Use both for the most complete picture. Many breeders run PennHIP early to screen prospects, then pursue OFA certification at two years.

Screening is one piece of the puzzle. Pedigree health history, sibling and offspring results, body condition and exercise during growth all influence hip health.

This article is for general information and does not replace an individual veterinary assessment. Talk to your veterinarian about the right screening plan for your dog.