Developmental Dysplasia of the Hip

Question 1

Define Developmental dysplasia of the hip

Answer 1

A spectrum of condition affecting the proximal femur and acetabulum, ranging from acetabular immaturity to hip subluxation and frank hip dislocation

Question 2

Define true developmental dysplasia of the hip

Answer 2

Femoral head has a persistently abnormal anatomical relationship with the pelvic acetabulum, which leads to abnormal bony development that can ultimately result in premature arthritis and significant disability

Question 3

Define transient dysplasia of the hip

Answer 3

acetabular immaturity in which the anatomical relationship stabilises and normalises over a period of weeks to months

Question 4

What are the risk factors for developmental dysplasia of the hip

Answer 4

Female sex (6 fold increase in risk)
Family history
Breech presentation
Neuromuscular disorder
First-born infants
Large infants
Talipes

Question 5

What is the screening programme for developmental dysplasia of the hip

Answer 5

All babies are screened for DDH during the NIPE: Ortolani’s and Barlow’s test at birth and 6 weeks

Breech position at 36 weeks (regardless of position at birth): US of the hip 6 weeks postpartum

Question 6

What are the symptoms and signs of developmental dysplasia of the hip

Answer 6

Appearance
One leg appears shorter than the other
Extra deep crease on the inside of the thigh
The knee appears to face outwards

Movement
One hip joint moves differently from the other
One leg does not appear to move outwards as fully as the other e.g. during nappy changes
Crawling with one leg dragging
Unilateral toe-walking

Question 7

Describe Barlow’s manoeuvre

Answer 7

The femoral head is adducted and gently pushed downwards
DDH: the femoral head moves posteriorly out of the acetabulum

Question 8

Describe Ortolani’s manoeuvre

Answer 8

Gentle upward leverage is applied while abducting the hip

DDH: dislocated hip will relocate into the acetabulum with a ‘clunk’

Question 9

What investigations should be done for DDH

Answer 9

<6 months → US hips: Subluxation on provocative testing, Abnormal relationship between femoral head and acetabulum (acetabular index)

> 6 months → X-ray hip: Abnormal relationship between femoral head and acetabulum (assessed by acetabular index, Shenton’s line, ossification of femoral head)

Question 10

What is the management for developmental dysplasia of the hip (with dislocation)

Answer 10

Seek specialist orthopaedic opinion

First line: hip abduction orthosis with a splint e.g. Pavlik harness
Second line: more rigid hip abduction splint
Third line: Reduction surgery and spica cast replacement

Question 11

What is the management for developmental dysplasia of the hip in children >6 years old

Answer 11

Salvage osteotomies
(little potential for remodelling at this age)

Question 12

What does closed reduction with spica casting involve

Answer 12

injection of dye into the joint to outline the cartilage of the femoral head to assess reduction + adductor tenotomy to decrease adduction contracture and allow increased abduction and femoral head stability before spica cast application

Question 13

What is the management for developmental dysplasia of the hip with dysplasia but no dislocation

Answer 13

<2 months with normal exam: observation with serial exams + US every month
Dysplasia worsening: Pavlik harness

Question 14

What are the complications of a Pavlik harness

Answer 14

Suboptimal positioning of the brace, forced abduction, excessive flexion → avascular necrosis (AVN) and nerve palsy e.g. femoral nerve palsy
Pavlik harness disease: Posterolateral acetabular erosion

Question 15

What are the complications of spica casting

Answer 15

Avascular necrosis (AVN)/proximal femoral growth disturbance
Residual acetabular dysplasia

Question 16

What are the complications of developmental dysplasia of the hip

Answer 16

Degenerative joint disease
Limb length inequality
Knee valgus
Back pain

Question 17

What is the prognosis for developmental dysplasia of the hip

Answer 17

Depends on age at presentation, extent of treatment, and complication occurrence
Early splinting in abduction reduces long-term morbidity
Pavlik harness: success rates 90% with low complication rates
Open reduction: higher complication rates

Question 18

What is the difference between hip dysplasia, subluxation, and hip dislocation

Answer 18

Hip dysplasia: a radiographic finding alone showing an imperfect degree of coverage of the femoral head by the acetabulum.

Hip subluxation: partial articulation of the joint surfaces. Clinically, this manifests as a hip that has a greater degree of laxity than normal with provocative testing, reflecting greater than normal movement of the femoral head within the acetabulum, but which is not fully dislocated or dislocatable.

Hip dislocation: the femoral head sits fully outside of the acetabulum, either at rest or with provocative testing.