Training Manual Table of Contents Chapter 1: Introduction and Overview ............................................................................................... 5 Brief History of PennHIP ........................................................................................................................................5 Current Status of CHD ...........................................................................................................................................5 Requirements for Improved Hip Screening ............................................................................................................6 PennHIP Strategies ................................................................................................................................................7 The AIS PennHIP Procedure .................................................................................................................................8 AIS PennHIP Certification ......................................................................................................................................8 Purchasing a Distractor ..........................................................................................................................................9 Antech Imaging Services........................................................................................................................................9 Summary ............................................................................................................................................................. 10 Chapter 2: CANINE HIP DYSPLASIA: Etiology, Pathogenesis, and Diagnosis ............................. 11 Introduction .......................................................................................................................................................... 11 Etiology and Pathogenesis .................................................................................................................................. 11 Hip Development ................................................................................................................................................. 12 Biomechanics ...................................................................................................................................................... 14 Genetics .............................................................................................................................................................. 16 Joint Laxity .......................................................................................................................................................... 17 Joint Fluid ............................................................................................................................................................ 19 Pelvic Muscle Mass ............................................................................................................................................. 20 Hormonal Factors ................................................................................................................................................ 20 Weight and Growth .............................................................................................................................................. 21 Nutrition ............................................................................................................................................................... 22 Environmental Factors ........................................................................................................................................ 22 Other Causes ...................................................................................................................................................... 23 Proposed Pathogenesis of Hip Dysplasia ........................................................................................................... 23 Signalment and History ....................................................................................................................................... 25 Physical Examination .......................................................................................................................................... 26 Imaging Examination ........................................................................................................................................... 28 Radiography ........................................................................................................................................................ 28 Hip-Extended Radiography ................................................................................................................................. 28 Orthopedic Foundation for Animals ..................................................................................................................... 30 Fédération Cynologique Internationale ............................................................................................................... 33 British Veterinary Association/Kennel Club ......................................................................................................... 33 Neutral-Position Radiography: AIS PennHIP ...................................................................................................... 34 2 Dorsolateral Subluxation ..................................................................................................................................... 37 Flückiger Subluxation Index ................................................................................................................................ 39 Palpation.............................................................................................................................................................. 40 Ultrasound ........................................................................................................................................................... 40 Computed Tomography and Magnetic Resonance Imaging ............................................................................... 42 Chapter 3: Controlling Canine Hip Dysplasia ................................................................................. 44 Ideal Hip Screening Requirements ..................................................................................................................... 44 Genetic Change: The Importance of Heritability and Selection Pressure ........................................................... 46 Selection Pressure and Its Role in Genetic Change ........................................................................................... 50 Reported Improvements in Hip Phenotype ......................................................................................................... 51 Are We Hitting the Bull's-Eye? ............................................................................................................................ 53 Summary ............................................................................................................................................................. 56 References .......................................................................................................................................................... 56 Chapter 4: How to Perform the AIS PennHIP Procedure ................................................................ 68 Course Overview ................................................................................................................................................. 68 Three Radiographic Views .................................................................................................................................. 68 Preparation .......................................................................................................................................................... 69 Record Keeping ................................................................................................................................................... 70 Sedation and Anesthesia .................................................................................................................................... 71 Patient Positioning ............................................................................................................................................... 71 Hip-Extended View .............................................................................................................................................. 72 Compression View .............................................................................................................................................. 75 Distraction View ................................................................................................................................................... 78 Cavitation ............................................................................................................................................................ 82 Recommendations for Those Who Cavitate Frequently ..................................................................................... 83 Helpful Hints and Tidbits ..................................................................................................................................... 83 Chapter 5: The Good, the Bad, and the Ugly: Reasons