View source for 2 – Congenital dislocation of the hip

== 7. DDH (developmental dysplasia of the hip), etiology and pathology of ==
* DDH is the most common congenital musculoskeletal deformity
** Affects approx. 2 out of 100 000 newborns in Europe
* Left hip is slightly more often affected than the right
** Bilateral DDH is rare
* Etiology
** Girls > boys
** Breech position during delivery
*** Causes abnormal flexion of the hip
** Firstborn children > later-born children
** Family history
** Oligohydramnios
* Pathology
** The acetabulum is dysplastic and shallow
*** Normally the acetabulum contains 2/3 of the femoral head
*** In DDH the acetabulum contains less than 2/3
*** This increases the pressure on the surface of the hip
** Subluxation / dislocation of the femoral head
*** Due to the shallow acetabulum
* Secondary changes
** Occurs in untreated DDH -> secondary changes develop in the femoral head and acetabulum
** These secondary changes make hip reduction more and more difficult
** Bony changes
*** Delayed ossification of femoral head
*** Increased femoral antetorsion
**** = the shaft of the femur has a torsion, causing the femoral neck to rotate anteriorly
**** This increases the angle between the femoral neck and the condylar axis
*** Increased collodiaphyseal angle
*** Coxa valga
**** Due to increased collodiaphysal angle
** Soft tissue
*** Loose capsule
*** Abnormal position of iliopsoas
**** The iliopsoas normally runs in front of the head of the femur
**** In DDH the tendon of the iliopsoas comes between the cavity of the acetabulum and the head of the femur
**** This makes it difficult to reduce the head of the femur through the narrowed opening

== 38. DDH, clinical and X-ray features of ==
* Clinical features
** Limited motion of the limb
*** Especially abduction (adduction contracture)
** Asymmetric skin folds on the thigh and gluteal region
** Positive Barlow sign
*** A click is heard and felt when pressure is applied to dislocate the hip
*** This test shows that the hip can be dislocated, but is not currently dislocated
** Positive Ortolani sign
*** A click is heard and felt when pressure is applied to reduce the hip
*** This test shows that the hip is reduceable and therefore currently dislocated
*** Positive Ortolani sign is the only definitive sign of DDH
** Late
*** Limb length difference
*** Trendelenburg gait
* Diagnosis
** Screening at birth, 3 weeks, 3 months, 6 months
*** Only in those with risk factors or if there is clinical suspicion
*** US or X-ray
** Ultrasound
*** Used for infants < 4 months
*** Can detect clinically silent DDH
** X-ray
*** Used for infants > 4 months
*** In AP and Lauenstein view
*** Shows acetabular dysplasia and hip location
*** Femoral head is above the Hilgenreiner line
*** Femoral head is lateral to the Perkin line

== 41. Conservative treatment of DDH ==
* If patient is < 6 months
* Baby must use a so-called Pavlik harness or an abduction splint, which secures the baby’s hips in a stable “frog-leg” position, allowing them to develop normally
** Pavlik harness fixes the femoral head in the correct position
** Over the time acetabulum will be deepened
** Abnormal use of the Pavlik harness can cause osteonecrosis of the femoral head
* Pavlik harness rapidly becomes ineffective after 4 months of age -> abduction splint or plaster cast
* Has high success rate when used correctly

== 52. Surgical treatment of DDH (developmental dysplasia of the hip) ==
* If patient is already > 6 months old OR conservative treatment didn’t work
* The specific surgical treatment depends on the exact pathology, but it always involves open reduction of the joint
* Other procedures which may be necessary
** Soft tissue procedures
*** Adductor and/or iliopsoas muscles may need operation because they adapt to the dislocated joint, causing contracture
** Femur osteotomy (= varus de-rotational osteotomy)
*** Corrects collodiaphyseal angle and antetorsion
** Pelvic osteotomy (= acetabulum-plasty)
*** Dega osteotomy
**** Done when socket is too wide and too shallow
*** Salter osteotomy
**** Done when the socket doesn’t sit properly on the femoral head
* Patient must wear spica cast afterwards

[[Category:Orthopaedics (POTE course)]]