PennHip (University of Pennsylvania Hip Improvement Program) is an alternative scoring technique for hips developed in 1983.  Dogs are anaesthetised in a similar manner to the current hip scheme; however screening can be done from 12 weeks of age.  Three X-rays are taken:

  • a hip extended view;
  • a compression view (where hips are pushed into the socket); and
  • a distraction view (where hips are distracted out of the sockets).

Neither compression nor distraction is done in a forceful way.  The technique is accurate and repeatable.  The distractive index (DI) measures the relative difference between the position of the femoral head (ball) during compression and distraction.  It is a true measure of Passive Hip Laxity.  Distractive indices are compared with others of the same breed.  This allows an excellent appraisal of individual dogs and their suitability for breeding.  Because the heritability of DI is high (64% in the Golden Retriever), breeding with dogs with DI scores better than the median for the breed can result in quick improvement in the DI within two to three generations.