Definition and clinical diagnosis of Canine Hip Dysplasia; early diagnosis and treatment

Hip dysplasia is the most widespread disease causing osteo-arthritis in dogs of all breeds. The severity of hip dysplasia varies with the grade of osteoarthritis that develops during life. Hip dysplasia affects the well being and performance of the animal, although it is endured by most dogs because of a high tolerance to chronic pain and weight-bearing compensation of the forelimbs. Severe hip dysplasia can be incapacitating or result in a decrease in physical performance, both of which reduce the quality of the patient’s life. The severity of the disease is also affected by the environment (diet/weight, exercise/activity) and is related to the degree of osteoarthritis that develops. Canine hip dysplasia (CHD) is a progressive disease, which develops during postnatal skeletal growth. A definitive diagnosis can be made radiographically when secondary signs of osteoarthritis due to joint incongruity become evident. However, at this point it is too late to prevent osteoarthritis. However, if joint incongruity is diagnosed before
the start of degenerative joint changes, osteoarthritis can be prevented. The development of hip dysplasia can be diagnosed during the growth period; the more severe the hip dysplasia, the earlier the diagnosis can be made based on the early clinical and radiographic signs of the disease. Predictive clinical and radiographic signs are related to joint morphology and congruity and to the detection and measurement of joint laxity (Ortolani sign, subluxation and distraction index) and of the slope of the dorsal acetabular rim. The predictive value of early diagnosis can be confirmed by clinical and radiographic monitoring of cases that are treated conservatively. By using a standardized diagnostic protocol and by monitoring the development of the hip
disease in untreated dogs, the prognostic usefulness of an early diagnosis can be greatly improved. Early diagnosis and proper treatment can arrest and reverse the progression of disease and change its pathogenesis.
Triple pelvic osteotomy (TPO) performed in puppies with femoral head subluxation increased the dorsal acetabular rim slope. In puppies without signs of osteoarthritis, this technique modified the direction of the forces inside the joint leading to a redirection of the femoral head inside the acetabulum. During the residual growth period, the femoral head and the acetabulum regain their joint congruity through uniform cartilage loading, thus preventing or limiting osteoarthritis. The recently described juvenile pubic symphysiodesis (JPS) is a technique intended to modify the slope of the acetabular roofs in a more ventral direction during skeletal growth in puppies with signs that indicate the start of hip dysplasia. Limiting the circumferential growth of the pelvic canal by arresting the pubic symphysis results in bilateral acetabular rotation, which improves coxofemoral coverage by the acetabular roofs. In the residual growth period, joint congruity is improved, thus allowing more favourable joint biomechanics and preventing or limiting osteoarthritis.