DEVELOPMENTAL DYSPLASIA OF THE HIP (DDH)DEFINITION, EPIDEMIOLOGY,ETIOPATOLOGYCY,MF,AM,NA,DI

DDH = developmental dysplasia of the hip Coined in 1980s as it is accepted that dislocation is not always congenital (CDH) & may be acquired It covers a range between acetabular dysplasia & dislocation (dislocatable, irreducible, early or late) Dislocation can present either Early - at birth or in neonatal period, or Late - usually with a dislocated hip after 6/12 of age

EpidemiologySignificant DDH = 2 per 1000 live birthsUnstable hips at birth = 5-20 per 1000F:M = 7:1Left > right hip, 1 in 5 bilateralMore common if1. Female2. Breech (decreased intrauterine space)3. 1st born (decreased intrauterine space)4. Oligohydramnios (decreased intrauterine space)5. Family HistoryAssociated with other 'packaging disorders' like torticollis & metatarsus adductus

Etiology1. Genetic factors DDH runs in families2. Hormonal factors High levels of maternal oestrogen, progesterone & relaxin in last weeks of pregnancy, May aggravate ligamentous laxity3. Mechanical factors Intrauterine malposition or decreased intrauterine space Unfavourable forces on hip in utero Postnatal factors Swaddle babies & carry them with legs together, hips & knees fully extended ,May -> persistence of neonatal instability & acetabular maldevelopment

PatologyFemoral head Femoral head & neck remain anteverted & in valgus position Pulled proximally & laterally by hip abductors Becomes misshapen & flattened and it Has delayed ossification of capital epiphysis

Acetabulum Becomes flattened (dysplastic) because not stimulated to develop around absentfemoral head AntevertedAcetabular labrum Becomes enlarged along superior, posterior, & inferior rim May infold into joint (inverted limbus) Limbus blocks reduction of femoral head

Ligamentum teres becomes lengthened, hypertrophic & redundantTransverse acetabular ligament is pulled superiorly with capsule which blocks lowerportion of acetabulumCapsule of hip joint becomes expandedHip joint fills with fibrofatty debris known as pulvinarMuscles Crossing hip joint (hamstring, hip adductors, & psoas) become shortened & contracted

THANK YOU