The prevalence of hip dysplasia and hip dislocation is 2 to 5%—a thousand times that of all other named (1) pediatric hip disorders, with the exception of transient synovitis (0.076%). Hip dysplasia is also by far the most common hip disorder in children. In Anglo-American speaking countries, only unstable hips and later sub-dislocations or dislocations are treated; their reported incidence is 0.089–0.115% (2). Preventing instability by treating the dysplasia is obviously not a medico-economic goal.
Biomechanically, the hip joint develops as a result of the functional interaction between the joint head and socket over time. Fundamentally crucial for this is the optimal dynamic surface pressure load. Too small a socket surface or dysplasias undoubtedly reduce the resilience and lifespan of the joint.
In German-speaking countries, the introduction/establishment of Graf infant hip ultrasound screening in 1984 revolutionized the earliest diagnostic evaluation and treatment of abnormalities of hip development. If ultrasound, treatment, and follow-up are carried out correctly, then—except for very few individual cases of teratogenic or neuromuscular origin—late sequelae of abnormalities of hip development can now be ruled out completely, compare to the past. High quality investigation as a result of thorough training is key. I myself investigated 26 414 children by Graf hip ultrasound examination; none of the children I treated from the beginning ever required subsequent surgery (3).
Using the Gocht–Shenton–Ménard line on the pelvic radiograph to assess the situation will yield results only where the hip joint is decentered, not in stable dysplasia.
Whether even dysplastic hips should be diagnostically evaluated and treated is not unclear: on the contrary, after completion of the first year of life sonographic follow-up monitoring of treated hips should become mandatory, as well as sonographic sceening by means of a qualified technique in at-risk groups (neuromuscular/Perthes disease, slipped capital femoral epiphysis/competitive sport) until the end of the growth period (4).
Footnotes
Conflict of interest statement
The authors is the main organizer of the Munich working group for orthopedic ultrasound.
References
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