133-发育性髋关节脱位(英文).ppt

Developmental Dysplasia of the Hip Heather Roche April 4 , 2002 Previously known as congenital dislocation of the hip implying a condition that existed at birth developmental encompasses embryonic, fetal and infantile periods includes congenital dislocation and developmental hip problems including subluxation, dislocation and dysplasia Normal Growth and Development Embryologically the acetabulum, femoral head develop from the same primitive mesenchymal cells cleft develops in precartilaginous cells at 7th week and this defines both structures 11wk hip joint fully formed acetabular growth continues throughout intrauterine life with development of labrum birth femoral head deeply seated in acetabulum by surface tension of synovial fluid and very difficult to dislocate in DDH this shape and tension is abnormal in addition to capsular laxity The cartilage complex is 3D with triradiate medially and cup-shaped laterally interposed between ilium above and ischium below and pubis anteriorly acetabular cartilage forms outer 2/3 cavity and the non-articular medial wall form by triradiate cartilage which is the common physis of these three bones fibrocartilaginous labrum forms at margin of acetabular cartilage and joint capsule inserts just above its rim articular cartilage covers portion articulating with femoral head opposite side is a growth plate with degenerating cells facing towards the pelvic bone it opposes triradiate cartilage is triphalanged with each side of each limb having a growth plate which allows interstitial growth within the cartilage causing expansion of hip joint diameter during growth In the infant the greater trochanter, proximal femur and intertrochanteric portion is cartilage 4-7 months proximal ossification center appears which enlarges along cartilaginous anlage until adult life when only thin layer of articular cartilage persists Development cpn’t Experimental studies in humans with unreduced hips suggest the main stimulus for concave s