DDH Flashcards
What is DDH?
- = Spectrum of conditions involving abnormal development of hip joint, causing the femoral head to have an abnormal relation to acetabulum
Which hip is more commonly affected in DDH, and why?
- 65% left hip: related to intra-uterine posture, where L hip lies on mother’s sacrum
- 20% bilateral dysplasia
- 15% right hip
What is difficult about bilateral DDH?
May appear normal on examination!
What is the most common cause of DDH?
Ligament (capsular) laxity, which can occur from:
- Immature development of hip
- Maternal hormones released to help their ligaments relax (?oxytocin)
- Position of baby
Risk factors for DDH
- Female sex (80%)
- Twins
- FHx DDH
- Breech presentation
- IU packaging problems due to reduced uterine vol:
○ First pregnancies
○ Oligohydramnios (reduced amniotic fluid)
○ Multiple pregnancy - Post-natal wrapping of baby with legs extended
Aside from DDH, what can reduced uterine volume predispose to (thus what are some exam findings in DDH)?
○ Plagiocephaly (flattening of head)
○ Torticollis (twisting of neck)
○ Hyperextended knees
○ Foot deformities
What are some consequences of uncorrected DDH?
- If not corrected by 4yo, residual disease likely
- Child: developmental delay
- Adolescents: fatigue, hip pain, limp
- Adults: early osteoarthritis, joint replacement
Practically, how might you structure your examination for DDH?
- test hip instability first THEN asymmetry THEN general inspection, as baby can become unsettled
When should a child be examined for DDH?
- Important times: birth, 1 + 2 weeks, 1/2/4/8/12 mo
- Up to 3 and 1/2 yo
What are some dysmorphisms associated with DDH? (only have to know 1 really)
- Down’s
- Arthrogryposis
- Larsen syndrome
What asymmetrical signs might you see in DDH?
- Limitation of hip abduction in flexion - very sensitive sign in older infant (>6 months)
• Flex both hips to 90degrees
• Assess degree of abduction and resistance on both sides - Asymmetry of leg posture - child may lean to affected side when standing
- Uneven thigh and gluteal creases (soft sign)
- Shortened leg
- Often produces deep fold in gluteal region
How do you assess for length of legs?
Galeazzi test
• Flex both hips to 90degrees, neutral pelvis and abd/add
• Assess level of knees
How do you test for hip instability?
- Barlow test:
• One hand stabilises pelvis, other hand grasps other side knee (hand at greater trochanter)
• Flex knee to 90 degrees
• Adduct hip 10-20 degrees
• If subluxing, ‘gliding sensation of posterior movement’ will be felt from femoral head rubbing against edge of acetabulum
• If dislocating, ‘gliding sensation’ followed by distinct loss of resistance - Ortolani manouevre:
• Used to reduce a dislocated hip
• Both hips and knees flexed to 90 degrees
• Thumb grasps inside of knees, other fingers on greater trochanter
• As hip is abducted, other fingers try to lift femoral head back into acetabulum
• If reduced, ‘clunk’ sensation felt
Which imaging should you do to investigate DDH?
US - <6m (mostly cartilaginous)
XR - >6m (more bony development)
What is the Mx of DDH?
Dx < 6 weeks
- Confirmed DDH: simple bracing (e.g. Pavlik harness) will usually help hips to resolve by themselves
Dx > 3 months
- Soft tissue adaptive changes already occurred
- Ix Procedure: anaesthetic + arthrogram: contrast injected into joint to determine if hip can be reduced safely
- Mx:
• Reducible hip: closed reduction = hip spica (cast that covers from knees to waist)
• Irreducible hip: open reduction -> hip spica
Dx after walking age
- Bony adaptive changes well established
- Majority have open reduction -> hip spica +/- pelvic or femoral osteotomy to correct shape of bone
