2/11/2016 Jenelle Beadle Developmental Dysplasia of the Hip

Abnormal development of the acetabulum Acetabulum: “ball” of the ball-and-socket Normal DDH

Joint formation is completed by 11wks gestation As growth occurs, the acetabulum requires contact and pressure from the femoral head to maintain and develop its shape into a deep socket

1.An abducted position maximizes the force of the femoral head on the acetabulum, and is ideal for acetabular development Abduction Directs force into joint Optimal for development

1.An abducted position maximizes the force of the femoral head on the acetabulum, and is ideal for acetabular development Sustained adduction positioning may result in a shallow acetabulum Abduction Directs force into joint Optimal for development Adduction Directs force away from joint Bad for development

1.An abducted position maximizes the force of the femoral head on the acetabulum, and is ideal for acetabular development Sustained adduction positioning may result in a shallow acetabulum 2.If the femoral head is dislocated, pressure on the acetabulum is completely removed and it begins to grow shallow Dysplasia progresses if the femoral head does not “relocate” Typically a prenatal cause of dysplasia

1.An abducted position maximizes the force of the femoral head on the acetabulum, and is ideal for acetabular development Sustained adduction positioning may result in a shallow acetabulum 2.If the femoral head is dislocated, pressure on the acetabulum is completely removed and it begins to grow shallow Dysplasia progresses if the femoral head does not “relocate” Typically a prenatal cause of dysplasia Lack of contact and pressure causes dysplasia: dislocation adducted position

4 periods of development with increased risk: 12wks – fetal legs rotate medially risk for dislocation

4 periods of development with increased risk: 12wks – fetal legs rotate medially risk for dislocation 18wks – hip muscles develop neuromuscular problems may lead to dislocation

4 periods of development with increased risk: 12wks – fetal legs rotate medially risk for dislocation 18wks – hip muscles develop neuromuscular problems may lead to dislocation 36-40wks – mechanical factors oligohydramnios and breech presentation both force the fetus into an adducted position Abducted Adducted Frank Breech 20% Incidence DDH

4 periods of development with increased risk: 12wks – fetal legs rotate medially risk for dislocation 18wks – hip muscles develop neuromuscular problems may lead to dislocation 36-40wks – mechanical factors oligohydramnios and breech presentation both force the fetus into an adducted position Postnatal - mechanical factors positioning that forces the infant into an adducted position (worse if legs are extended)

Abnormally formed acetabulum (shallow socket) Normal Acetabulum DDH

Abnormally formed acetabulum (shallow socket) results in instablility of the joint (ball doesn’t stay in it)

Subluxation Femoral head moves within the acetabulum Dislocation Femoral head has no contact with the acetabulum Assessed by performing dynamic maneuvers with live ultrasound observation Barlow test

Designed to stress and dislocate an unstable hip Adduct and push posteriorly monitor for subluxation or dislocation Performed blindly by pediatricians as a routine screening feel for a “clunk” that indicates dislocation

Designed to identify dislocated hips by manual reduction Abduct while pulling slightly on the leg Performed by pediatricians in conjunction with the Barlow test feel for a “clunk” that indicates reduction Not useful in sonographic evaluation

Designed to encourage natural acetabular growth and development

Remember: A lack contact and pressure causes dysplasia of the acetabulum: dislocation adducted position

Designed to encourage natural acetabular growth and development Improve contact and pressure of the femoral head on the acetabulum by: reduction abducted position Remember: A lack contact and pressure causes dysplasia of the acetabulum: dislocation adducted position

Double diapering no longer recommended Pavlik harness 1-6 mos old Duration: 6+ wks Spica cast 6-24 mos old Duration: Surgery open reduction repair femoral neck angle osteotomy >2yrs spica cast used for recovery period

Evaluation for developmental dysplasia of the hip (DDH) Assess progress during treatment Establish normalcy and stability post treatment

Direct signs of DDH positive findings on Ortolani or Barlow (clunk) Secondary signs of DDH that persist >2 weeks Leg length discrepancy Asymmetrical thigh folds Equivocal dynamic testing Significantly increased risk for DDH breech presentation Mild risk factors alone are not considered significant enough to warrant an ultrasound screening female family history

Scheduling Evaluation of infants >6 mos (adjusted age) becomes limited ossification of femoral head reduces accuracy Evaluation of infants <4 wks is not recommended normal ligament elasticity can create false positive results Scanning Sonographer may perform entire exam Radiologist required to participate in dynamic evaluation Warm blankets, warm gel, pacifiers warm, sterile gel is required for neonates

Formed by the three pelvic bones Ilium (2/5) forms the upper “roof” – where US measurement is performed Ischium (2/5) forms the posterior and inferior portion Pubis (1/5) forms the anterior boundary Formed where the three pelvic bones meet Allows for growth of the acetabulum and pelvis Closes off by 15yrs

Infant hip ossification White = Cartilage Shaded = Ossified Bone Birth Puberty US of the hip is performed when the hip is largely cartilaginous

9 Months AdultChild 2 Months

Flexed or neutral Degree of flexion will change visualized femoral anatomy Head, GT, metaphysis

Ilium straight & parallel to the transducer sharp ilium-roof angle Triradiate cartilage Labrum

Right Left Right and left appear identical (label carefully)

Rt Angle that the acetabular roof makes with the ilium reflects the depth of the acetabulum Normal: >60 degrees

Percentage of the femoral head within the acetabulum reflects how the femoral head is seated within the joint Rt Normal: >50%

Flexed or neutral Degree of flexion will change visualized femoral anatomy Head, GT, metaphysis Barlow

RightLeft Right and left are mirrored

Ischium RightLeft Pubis Tri Cart Posterior

Designed to stress and dislocate an unstable hip Adduct and push posteriorly monitor for subluxation or dislocation 2-3 mm of movement is normal

RightLeft Posterior Barlow forces the hip posterior