Glossary

PennHIP

A hip screening method that measures joint looseness with a stressed x-ray, reported as a distraction index, and can be done in puppies from 16 weeks.

Also called: PennHIP, distraction index, hip laxity test, hip screening, PennHIP method

PennHIP is a method of measuring how loose a dog's hip joints are, developed at the University of Pennsylvania. A trained veterinarian takes three x-rays under sedation or anaesthesia, including one in which the thighbones are gently pushed apart. The result is the distraction index, a number between 0 and 1. A higher number means looser hips.

The test can be done as early as 16 weeks, much younger than an OFA final hip rating, which needs the dog to be 24 months. The index is compared with other dogs of the same breed in the PennHIP database, so a dog is ranked against its breed. Only certified veterinarians can submit the films.

Hip laxity is one factor in the risk of hip dysplasia, but it does not give a diagnosis for a particular dog. Different breeders use one method or both as part of health testing. For a pet with limping, ask your veterinarian.

Last reviewed November 8, 2026

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Related terms

Orthopedic Foundation for Animals A US non-profit that keeps open databases of health screening results for dogs, including hip and elbow ratings, to help breeders choose healthy parents. Health testing The screening of breeding dogs for inherited conditions, such as hip, elbow, heart, eye and DNA tests, whose results are shared with buyers. Dog breeder A person who plans and raises litters of puppies; a responsible breeder health tests the parents, follows a breed standard and stays involved with each puppy. Dog DNA test A cheek-swab or blood test that analyses a dog's genes to estimate its breed mix, check for inherited disease variants or identify certain traits.