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Type:
Educational Exhibit
Keywords:
Dysplasias, Education, Diagnostic procedure, MR, CT, Conventional radiography, Musculoskeletal soft tissue, Musculoskeletal joint
Authors:
N. Arevalo, N. Santamaria, E. Diez, J. Gredilla Molinero, M. Grande Barez; Madrid/ES
DOI:
10.1594/ecr2016/C-0492
Background
Developmental dysplasia of the hip or DDH (also called congenital hip disease),
is a spectrum disorder characterized by an underdeveloped or shallow and upwardly sloping acetabulum (acetabular dysplasia) with decreased coverage of the femoral head,
ranging from mild forms to complete hip dislocation.
It may be associated with varying degrees of morphologic abnormalities of the proximal femur such as excessive femoral anteversion,
coxa valga or femoral head-neck deformity (cam deformity).
It is important to remark that hip dysplasia is not always due to DDH.
Normal development of the hip requires normal growth of both acetabulum and proximal femur,
as well as their physiologic mechanical interaction.
According to that,
hip development may be affected by many other different conditions such as cerebral palsy,
hereditary neuropathy,
poliomyelitis,
Down and Ehlers-Danlos syndromes,
skeletal dysplasias,
slipped femoral epiphysis and Perthes disease.
On the other hand, the triradiate cartilage may be injured by sepsis or trauma which can also cause incomplete acetabular growth.
Consequently,
it is difficult to distinguish among the various etiologies of hip dysplasia if no clinical history is available.
However,
the most common etiology of hip dysplasia is DDH.
Although most cases of DDH have no identifiable cause,
multiple risk factors have been established including female gender,
breech positioning in utero,
oligohydramnios and having a family history (first-degree relative) with DDH.
DDH more commonly affects the left hip and more than 80% of cases occur in females.
The deformity is bilateral in 40%,
with varying severity on either side.
Whilst many patients are identified in childhood,
there is a significant number of cases that present in adulthood.
The radiologic diagnosis of acetabular dysplasia in young adults may be evident but sometime is subtle and its final diagnosis will be based on the detection of an undercoverage of the femoral head by the acetabulum.
Interest in early diagnosis of acetabular dysplasia in young adults has increased because it is a well-recognized cause of hip pain and limited function leading to premature osteoarthritis,
and its surgical treatment has advanced in the last few years.
The outcomes of hip preservation procedures for adult hip dysplasia are strongly related to the degree of degenerative change that have already developed and it is independent of patient age.
These procedures reorient the acetabulum so that the femoral head is better covered (periacetabular osteotomy),
restoring previously abnormal biomechanics and delaying or even preventing the development of osteoarthritis.
When degenerative changes are already established,
the only therapeutic option will be hip replacement including standard total hip arthroplasty or hip resurfacing arthroplasty,
the latter especially in younger patients whose life expectancy after implantation is long.