# Developmental dysplasia of the hip

Developmental dysplasia of the hip

- DDH defines the spectrum of  hip instability , ranging from the hip that is in joint but has a shallow (dysplastic) acetabulum and may be ‘pushed out’ (Barlow positive) to the dislocated hip that is irreducible (Ortolani negative). The clinical picture varies with the pathology and the age at presentation: neonatal hips may be unstable, a toddler may limp, adolescents may experience exercise-induced pain and an adult may have pain - secondary to degenerative arthritis. Incidence The incidence of  neonatal instability is approximately 20 per 1000 live births, whereas that of  true dislocation is approxi - mately 2 per 1000 live births; many hips stabilise spontaneously . Aetiology of developmental dysplasia of the hip /uni25CF Gender . Four to five times more common in girls, possibly related to hormonal factors causing temporary joint laxity in the peripartum period. /uni25CF Breech presentation . More common in breech babies, particularly with the extended breech position. /uni25CF Birth order . More common in firstborns and in the left hip because of  the common fetal position (left occipito - anterior) in a tight primigravid uterus where movement is restricted. /uni25CF Oligohydramnios . Restricts fetal movement. The presence of  other postural deformities (torticollis and metatarsus adductus) raises the possibility of  DDH. /uni25CF Family history . A positive family history significantly increases the risk of  DDH. /uni25CF Regional and racial variation . More common in certain regions and in certain races because of a combina - tion of  genetic, environmental and cultural factors. /uni25CF Swaddling the legs together exacerbates hip insta - bility , whereas carrying the baby astride the carer’s hip or back encourages hip flexion and abduction that improve stability . Hip dislocation is often found in association with gener - alised syndromes or neuromuscular conditions. These terato - logical hips ar e often resistant to the simpler treatments and a holistic approach to the child’s overall condition and prognosis must be taken. Diagnosis Neonate /uni25CF Clinical assessment and screening . In many coun - tries, neonates are screened for limitation of  hip abduction and hip joint instability . In the UK, as part of  the newborn and infant physical examination (NIPE) guidelines, the hips are examined again at 6 weeks. The knees and hips are flexed and the thigh held b y the examiner with the thumb trochanter. The hips are abducted gently: if  abduction is limited, the hip may be dislocated. The examiner’s finger then lifts the greater trochanter upwards; a soft clunk – the Ortolani test – with improved hip abduction signifies hip reduction ( Figure 44.13a ). If  the hip does abduct fully , then the flexed hip is brought back to neutral and then adducted while downward pressure is applied to the knee with the examiner’s thumb and palm: an unstable hip may dislocate or sublux – the Barlow test ( Figure 44.13b With an irreducible hip there is no clunk of  reduction but there will be limitation of  abduction. Bilateral dislocation may be missed because abduction is symmetrical and ab duction may be normal when there is low muscle tone and joint laxity . In a dislocated hip, the femoral head may be palpable in the buttock. /uni25CF Ultrasonographic assessment . Ultrasonography defines the anatomy and the stability of the hip joint. It is used as a screening tool (universally or selectively for ‘at risk’ patients) ( Figure 44.14 ). Screening scans should be performed between 4 and 6 weeks of  age and treatment, when necessary , started by 6 weeks. The sonographic appearance of  most hips impro ves (in terms of  both hip stability and acetabular dysplasia) spontaneously as the baby grows. /uni25CF Radiography . Plain radiographs are used from 4–5 months of  age, when the relationship of  the femoral ossific nucleus to the acetabulum can be assessed; late ossi fication of  the nucleus is common in DDH ( Figure 44.15 Infant Hip checks, looking for limitation of abduction in more than 90° of  flexion and limb shortening, are part of  developmental monitoring. Child Children present with a Trendelenburg gait and/or unilateral tiptoeing, as the a ff ected leg is short. Abduction in flexion is Friedrich Trendelenburg , 1844–1924, successively Professor of  Surgery at Rostock (1875–1882), Bonn (1822–1895) and Leipzig (1895–1911), Germany . The neonatal clinical examination must ask and answer the following questions: /uni25CF /uni25CF /uni25CF /uni25CF ). /uni25CF /uni25CF - limited and there may be an extra thigh crease. The signs may be subtle and easily missed in an unsteady toddler. If  both hips are a ff ected there will be a waddling gait and a lumbar lordosis. - Adolescent Discomfort after exercise is common but the pain may be in the knee. In all age groups, radiographs may show dysplasia, sublux - ation or dislocation. Summary box 44.6 - ). Diagnosis of DDH /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF 

(a)
Figure 44.13
Line diagram illustrating the
(a)
Ortolani and
(b)
Barlow tests for developmental dysplasia of the hip. For the Barlow test the femur
must be at 90° to the bed.
Is the hip dislocated?
If so, is it reducible (Ortolani positive) or not (Ortolani
negative)?
If the hip is not dislocated, is it dislocatable (or subluxable)?
If so, it is Barlow positive
If the hip is not dislocated or dislocatable, is it clinically
normal?
If so, do the risk factors in the history still demand further
assessment with an ultrasound scan or plain radiograph?
Based on the history and clinical examination and con
/f_i
rmed
by appropriate investigations
All neonates are screened clinically (Barlow and Ortolani tests)
at birth and at 6 weeks
Ultrasound is used as a selective screening test in ‘at-risk’
babies
Radiography is useful from 4 months onwards
Older children present with a limp and/or tiptoeing and a
lumbar lordosis in bilateral cases
(b)

a (c) Management The objective is to obtain a stable, congruous reduction of  the femoral head within the acetabulum while avoiding damage to the capital epiphysis (avascular necrosis [A VN]), which causes sti ff ness and proximal femoral deformity . Neonate Owing to the peripartum hormonal e ff ects many neonatal hips are unstable. Most stabilise spontaneously by 6 weeks. Hips that remain unstable or that are dislocated at rest are treated with harnesses or splints that obtain and maintain reduction with the hip abducted and flexed. Joint stability is monitored with ultrasound scanning. Most harnesses ( Figure 44.16 ) allow controlled mo vement while splints hold the hips more rigidly and may carry a greater risk of  A VN and femoral nerve palsy . If  the hips fail to relocate or stabilise, treatment should be discontinued. Christian Morin , contemporary , French paediatric orthopaedic surgeon. Heinrich Hilgenreiner , 1870–1954, German surgeon and orthopaedist. George Perkins , 1892–1980, Professor of  Surgery , St Thomas’ Hospital, London, UK, described signs by which to diagnose congenital dislocation of  the hip in 1928. a α α a b Infant Successful harness treatment is unusual after the age of 4–6 months. For the late-presenting hip or one that fails conservative treatment, an examination under anaesthetic may achieve a closed reduction. A psoas/adductor release can 

(c)
Figure 44.14
Ultrasound images of an infant hip.
(a)
Normal hip with
a high
angle and a Morin index of 50% (de
/f_i
ned as the percentage
of the femoral head covered by the acetabulum, i.e. the portion lying
below the horizontal red line).
(b)
Grossly dysplastic hip with a low
angle and a Morin index of <50%. This hip is likely to be unstable on
dynamic ultrasound scanning, i.e. Barlow positive.
(c)
A dislocated
hip joint (dislocated femoral head, red arrow; ‘empty’ acetabulum,
white arrow).
Figure 44.15
Anteroposterior pelvic radiograph showing Hilgenrein
-
er’s line (a) and Perkins’ line (b). The femoral head (ossi
/f_i
c nucleus) of
a normal hip lies in the inner lower quadrant. The right hip is normal;
the left hip has developmental dysplasia of the hip.

be performed if  the arthrogram suggests they are blocking reduction or limiting stability . Postoperatively , a spica cast maintains hip reduction. If  the hip is irreducible or can only be held reduced in an extreme position then treatment should be abandoned and an open reduction considered via a medial or anterior approach. Summary box 44.7 Management of early DDH /uni25CF /uni25CF /uni25CF /uni25CF Child A medial approach open reduction can be performed between 6 and 24 months of  age. An anterior approach to the hip (from 9–12 months of  age) allows for a simultaneous capsulorrhaphy . In the older child, a pelvic osteotomy may be required to reorientate the acetabulum, and femoral shortening or derotation osteotomies will improve stability ( Figure 44.17 Arnold Pavlik , 1902–1962, Czech orthopaedic surgeon, became famous mainly for the development of a functional, active method of treating developmental dysplasia of  the hip. Surgery is contraindicated in children over the age of  6–8 years in bilateral cases and the age of  8–10 years in unilateral cases ( Figure 44.18 ). Adolescent Hips are often dysplastic and subluxated. If the hip is reducible, the joint can be reconstructed with a combination of  pelvic and femoral osteotomies. For the irreducible hip, acetabular augmentation may reduce symptoms and delay the onset of degenerative change. ). 

Shoulder strap
Chest strap
Flexion strap
A
bduction strap
Leg strap
Figure 44.16
The anterior strap of the Pavlik harness controls hip
/f_l
exion, whereas the posterior strap limits adduction and encourages
abduction.
Many hips that are unstable in the
/f_i
rst 2–3 weeks of life
require no treatment as they improve spontaneously
Up to age 4–6 months, a harness or splint is effective
treatment
In older babies, closed reduction is often possible
For failed closed treatment, open surgical reduction is required
Figure 44.17
Anteroposterior pelvic radiograph showing acetabular
dysplasia with subluxation (developmental dysplasia of the hip) of the
left hip. This child presented at age 7 years.
Figure 44.18
Anteroposterior pelvic radiograph showing bilateral true
dislocations in a 9-year-old child; the decision was made not to offer
an operation. The pathology in these hips is different from that shown
in
Figure 44.17
.

Management of late-presenting DDH /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF Secondary procedures and complications At follow-up, acetabular remodelling is assessed with the acetabular index or the centre–edge angle ( Figure 44.19 Surgery may be required for residual dysplasia or subluxation. A VN with trochanteric overgrowth causes a Trendelenburg limp: the outcome is poor ( Figure 44.20 ). Occasionally , a leg length di ff erence needs treatment. There is an increased risk of  osteoarthritis and hip arthroplasty later in life. 

The older the child, the more likely it is that they will require
surgery
Femoral osteotomy improves hip stability
Pelvic osteotomy redirects or reshapes the acetabulum
The potential for acetabular remodelling decreases after the
age of 3–4 years
Avascular necrosis is a risk with all DDH treatment

Developmental dysplasia of the hip

- DDH defines the spectrum of  hip instability , ranging from the hip that is in joint but has a shallow (dysplastic) acetabulum and may be ‘pushed out’ (Barlow positive) to the dislocated hip that is irreducible (Ortolani negative). The clinical picture varies with the pathology and the age at presentation: neonatal hips may be unstable, a toddler may limp, adolescents may experience exercise-induced pain and an adult may have pain - secondary to degenerative arthritis. Incidence The incidence of  neonatal instability is approximately 20 per 1000 live births, whereas that of  true dislocation is approxi - mately 2 per 1000 live births; many hips stabilise spontaneously . Aetiology of developmental dysplasia of the hip /uni25CF Gender . Four to five times more common in girls, possibly related to hormonal factors causing temporary joint laxity in the peripartum period. /uni25CF Breech presentation . More common in breech babies, particularly with the extended breech position. /uni25CF Birth order . More common in firstborns and in the left hip because of  the common fetal position (left occipito - anterior) in a tight primigravid uterus where movement is restricted. /uni25CF Oligohydramnios . Restricts fetal movement. The presence of  other postural deformities (torticollis and metatarsus adductus) raises the possibility of  DDH. /uni25CF Family history . A positive family history significantly increases the risk of  DDH. /uni25CF Regional and racial variation . More common in certain regions and in certain races because of a combina - tion of  genetic, environmental and cultural factors. /uni25CF Swaddling the legs together exacerbates hip insta - bility , whereas carrying the baby astride the carer’s hip or back encourages hip flexion and abduction that improve stability . Hip dislocation is often found in association with gener - alised syndromes or neuromuscular conditions. These terato - logical hips ar e often resistant to the simpler treatments and a holistic approach to the child’s overall condition and prognosis must be taken. Diagnosis Neonate /uni25CF Clinical assessment and screening . In many coun - tries, neonates are screened for limitation of  hip abduction and hip joint instability . In the UK, as part of  the newborn and infant physical examination (NIPE) guidelines, the hips are examined again at 6 weeks. The knees and hips are flexed and the thigh held b y the examiner with the thumb trochanter. The hips are abducted gently: if  abduction is limited, the hip may be dislocated. The examiner’s finger then lifts the greater trochanter upwards; a soft clunk – the Ortolani test – with improved hip abduction signifies hip reduction ( Figure 44.13a ). If  the hip does abduct fully , then the flexed hip is brought back to neutral and then adducted while downward pressure is applied to the knee with the examiner’s thumb and palm: an unstable hip may dislocate or sublux – the Barlow test ( Figure 44.13b With an irreducible hip there is no clunk of  reduction but there will be limitation of  abduction. Bilateral dislocation may be missed because abduction is symmetrical and ab duction may be normal when there is low muscle tone and joint laxity . In a dislocated hip, the femoral head may be palpable in the buttock. /uni25CF Ultrasonographic assessment . Ultrasonography defines the anatomy and the stability of the hip joint. It is used as a screening tool (universally or selectively for ‘at risk’ patients) ( Figure 44.14 ). Screening scans should be performed between 4 and 6 weeks of  age and treatment, when necessary , started by 6 weeks. The sonographic appearance of  most hips impro ves (in terms of  both hip stability and acetabular dysplasia) spontaneously as the baby grows. /uni25CF Radiography . Plain radiographs are used from 4–5 months of  age, when the relationship of  the femoral ossific nucleus to the acetabulum can be assessed; late ossi fication of  the nucleus is common in DDH ( Figure 44.15 Infant Hip checks, looking for limitation of abduction in more than 90° of  flexion and limb shortening, are part of  developmental monitoring. Child Children present with a Trendelenburg gait and/or unilateral tiptoeing, as the a ff ected leg is short. Abduction in flexion is Friedrich Trendelenburg , 1844–1924, successively Professor of  Surgery at Rostock (1875–1882), Bonn (1822–1895) and Leipzig (1895–1911), Germany . The neonatal clinical examination must ask and answer the following questions: /uni25CF /uni25CF /uni25CF /uni25CF ). /uni25CF /uni25CF - limited and there may be an extra thigh crease. The signs may be subtle and easily missed in an unsteady toddler. If  both hips are a ff ected there will be a waddling gait and a lumbar lordosis. - Adolescent Discomfort after exercise is common but the pain may be in the knee. In all age groups, radiographs may show dysplasia, sublux - ation or dislocation. Summary box 44.6 - ). Diagnosis of DDH /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF 

(a)
Figure 44.13
Line diagram illustrating the
(a)
Ortolani and
(b)
Barlow tests for developmental dysplasia of the hip. For the Barlow test the femur
must be at 90° to the bed.
Is the hip dislocated?
If so, is it reducible (Ortolani positive) or not (Ortolani
negative)?
If the hip is not dislocated, is it dislocatable (or subluxable)?
If so, it is Barlow positive
If the hip is not dislocated or dislocatable, is it clinically
normal?
If so, do the risk factors in the history still demand further
assessment with an ultrasound scan or plain radiograph?
Based on the history and clinical examination and con
/f_i
rmed
by appropriate investigations
All neonates are screened clinically (Barlow and Ortolani tests)
at birth and at 6 weeks
Ultrasound is used as a selective screening test in ‘at-risk’
babies
Radiography is useful from 4 months onwards
Older children present with a limp and/or tiptoeing and a
lumbar lordosis in bilateral cases
(b)

a (c) Management The objective is to obtain a stable, congruous reduction of  the femoral head within the acetabulum while avoiding damage to the capital epiphysis (avascular necrosis [A VN]), which causes sti ff ness and proximal femoral deformity . Neonate Owing to the peripartum hormonal e ff ects many neonatal hips are unstable. Most stabilise spontaneously by 6 weeks. Hips that remain unstable or that are dislocated at rest are treated with harnesses or splints that obtain and maintain reduction with the hip abducted and flexed. Joint stability is monitored with ultrasound scanning. Most harnesses ( Figure 44.16 ) allow controlled mo vement while splints hold the hips more rigidly and may carry a greater risk of  A VN and femoral nerve palsy . If  the hips fail to relocate or stabilise, treatment should be discontinued. Christian Morin , contemporary , French paediatric orthopaedic surgeon. Heinrich Hilgenreiner , 1870–1954, German surgeon and orthopaedist. George Perkins , 1892–1980, Professor of  Surgery , St Thomas’ Hospital, London, UK, described signs by which to diagnose congenital dislocation of  the hip in 1928. a α α a b Infant Successful harness treatment is unusual after the age of 4–6 months. For the late-presenting hip or one that fails conservative treatment, an examination under anaesthetic may achieve a closed reduction. A psoas/adductor release can 

(c)
Figure 44.14
Ultrasound images of an infant hip.
(a)
Normal hip with
a high
angle and a Morin index of 50% (de
/f_i
ned as the percentage
of the femoral head covered by the acetabulum, i.e. the portion lying
below the horizontal red line).
(b)
Grossly dysplastic hip with a low
angle and a Morin index of <50%. This hip is likely to be unstable on
dynamic ultrasound scanning, i.e. Barlow positive.
(c)
A dislocated
hip joint (dislocated femoral head, red arrow; ‘empty’ acetabulum,
white arrow).
Figure 44.15
Anteroposterior pelvic radiograph showing Hilgenrein
-
er’s line (a) and Perkins’ line (b). The femoral head (ossi
/f_i
c nucleus) of
a normal hip lies in the inner lower quadrant. The right hip is normal;
the left hip has developmental dysplasia of the hip.

be performed if  the arthrogram suggests they are blocking reduction or limiting stability . Postoperatively , a spica cast maintains hip reduction. If  the hip is irreducible or can only be held reduced in an extreme position then treatment should be abandoned and an open reduction considered via a medial or anterior approach. Summary box 44.7 Management of early DDH /uni25CF /uni25CF /uni25CF /uni25CF Child A medial approach open reduction can be performed between 6 and 24 months of  age. An anterior approach to the hip (from 9–12 months of  age) allows for a simultaneous capsulorrhaphy . In the older child, a pelvic osteotomy may be required to reorientate the acetabulum, and femoral shortening or derotation osteotomies will improve stability ( Figure 44.17 Arnold Pavlik , 1902–1962, Czech orthopaedic surgeon, became famous mainly for the development of a functional, active method of treating developmental dysplasia of  the hip. Surgery is contraindicated in children over the age of  6–8 years in bilateral cases and the age of  8–10 years in unilateral cases ( Figure 44.18 ). Adolescent Hips are often dysplastic and subluxated. If the hip is reducible, the joint can be reconstructed with a combination of  pelvic and femoral osteotomies. For the irreducible hip, acetabular augmentation may reduce symptoms and delay the onset of degenerative change. ). 

Shoulder strap
Chest strap
Flexion strap
A
bduction strap
Leg strap
Figure 44.16
The anterior strap of the Pavlik harness controls hip
/f_l
exion, whereas the posterior strap limits adduction and encourages
abduction.
Many hips that are unstable in the
/f_i
rst 2–3 weeks of life
require no treatment as they improve spontaneously
Up to age 4–6 months, a harness or splint is effective
treatment
In older babies, closed reduction is often possible
For failed closed treatment, open surgical reduction is required
Figure 44.17
Anteroposterior pelvic radiograph showing acetabular
dysplasia with subluxation (developmental dysplasia of the hip) of the
left hip. This child presented at age 7 years.
Figure 44.18
Anteroposterior pelvic radiograph showing bilateral true
dislocations in a 9-year-old child; the decision was made not to offer
an operation. The pathology in these hips is different from that shown
in
Figure 44.17
.

Management of late-presenting DDH /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF Secondary procedures and complications At follow-up, acetabular remodelling is assessed with the acetabular index or the centre–edge angle ( Figure 44.19 Surgery may be required for residual dysplasia or subluxation. A VN with trochanteric overgrowth causes a Trendelenburg limp: the outcome is poor ( Figure 44.20 ). Occasionally , a leg length di ff erence needs treatment. There is an increased risk of  osteoarthritis and hip arthroplasty later in life. 

The older the child, the more likely it is that they will require
surgery
Femoral osteotomy improves hip stability
Pelvic osteotomy redirects or reshapes the acetabulum
The potential for acetabular remodelling decreases after the
age of 3–4 years
Avascular necrosis is a risk with all DDH treatment

Developmental dysplasia of the hip

- DDH defines the spectrum of  hip instability , ranging from the hip that is in joint but has a shallow (dysplastic) acetabulum and may be ‘pushed out’ (Barlow positive) to the dislocated hip that is irreducible (Ortolani negative). The clinical picture varies with the pathology and the age at presentation: neonatal hips may be unstable, a toddler may limp, adolescents may experience exercise-induced pain and an adult may have pain - secondary to degenerative arthritis. Incidence The incidence of  neonatal instability is approximately 20 per 1000 live births, whereas that of  true dislocation is approxi - mately 2 per 1000 live births; many hips stabilise spontaneously . Aetiology of developmental dysplasia of the hip /uni25CF Gender . Four to five times more common in girls, possibly related to hormonal factors causing temporary joint laxity in the peripartum period. /uni25CF Breech presentation . More common in breech babies, particularly with the extended breech position. /uni25CF Birth order . More common in firstborns and in the left hip because of  the common fetal position (left occipito - anterior) in a tight primigravid uterus where movement is restricted. /uni25CF Oligohydramnios . Restricts fetal movement. The presence of  other postural deformities (torticollis and metatarsus adductus) raises the possibility of  DDH. /uni25CF Family history . A positive family history significantly increases the risk of  DDH. /uni25CF Regional and racial variation . More common in certain regions and in certain races because of a combina - tion of  genetic, environmental and cultural factors. /uni25CF Swaddling the legs together exacerbates hip insta - bility , whereas carrying the baby astride the carer’s hip or back encourages hip flexion and abduction that improve stability . Hip dislocation is often found in association with gener - alised syndromes or neuromuscular conditions. These terato - logical hips ar e often resistant to the simpler treatments and a holistic approach to the child’s overall condition and prognosis must be taken. Diagnosis Neonate /uni25CF Clinical assessment and screening . In many coun - tries, neonates are screened for limitation of  hip abduction and hip joint instability . In the UK, as part of  the newborn and infant physical examination (NIPE) guidelines, the hips are examined again at 6 weeks. The knees and hips are flexed and the thigh held b y the examiner with the thumb trochanter. The hips are abducted gently: if  abduction is limited, the hip may be dislocated. The examiner’s finger then lifts the greater trochanter upwards; a soft clunk – the Ortolani test – with improved hip abduction signifies hip reduction ( Figure 44.13a ). If  the hip does abduct fully , then the flexed hip is brought back to neutral and then adducted while downward pressure is applied to the knee with the examiner’s thumb and palm: an unstable hip may dislocate or sublux – the Barlow test ( Figure 44.13b With an irreducible hip there is no clunk of  reduction but there will be limitation of  abduction. Bilateral dislocation may be missed because abduction is symmetrical and ab duction may be normal when there is low muscle tone and joint laxity . In a dislocated hip, the femoral head may be palpable in the buttock. /uni25CF Ultrasonographic assessment . Ultrasonography defines the anatomy and the stability of the hip joint. It is used as a screening tool (universally or selectively for ‘at risk’ patients) ( Figure 44.14 ). Screening scans should be performed between 4 and 6 weeks of  age and treatment, when necessary , started by 6 weeks. The sonographic appearance of  most hips impro ves (in terms of  both hip stability and acetabular dysplasia) spontaneously as the baby grows. /uni25CF Radiography . Plain radiographs are used from 4–5 months of  age, when the relationship of  the femoral ossific nucleus to the acetabulum can be assessed; late ossi fication of  the nucleus is common in DDH ( Figure 44.15 Infant Hip checks, looking for limitation of abduction in more than 90° of  flexion and limb shortening, are part of  developmental monitoring. Child Children present with a Trendelenburg gait and/or unilateral tiptoeing, as the a ff ected leg is short. Abduction in flexion is Friedrich Trendelenburg , 1844–1924, successively Professor of  Surgery at Rostock (1875–1882), Bonn (1822–1895) and Leipzig (1895–1911), Germany . The neonatal clinical examination must ask and answer the following questions: /uni25CF /uni25CF /uni25CF /uni25CF ). /uni25CF /uni25CF - limited and there may be an extra thigh crease. The signs may be subtle and easily missed in an unsteady toddler. If  both hips are a ff ected there will be a waddling gait and a lumbar lordosis. - Adolescent Discomfort after exercise is common but the pain may be in the knee. In all age groups, radiographs may show dysplasia, sublux - ation or dislocation. Summary box 44.6 - ). Diagnosis of DDH /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF 

(a)
Figure 44.13
Line diagram illustrating the
(a)
Ortolani and
(b)
Barlow tests for developmental dysplasia of the hip. For the Barlow test the femur
must be at 90° to the bed.
Is the hip dislocated?
If so, is it reducible (Ortolani positive) or not (Ortolani
negative)?
If the hip is not dislocated, is it dislocatable (or subluxable)?
If so, it is Barlow positive
If the hip is not dislocated or dislocatable, is it clinically
normal?
If so, do the risk factors in the history still demand further
assessment with an ultrasound scan or plain radiograph?
Based on the history and clinical examination and con
/f_i
rmed
by appropriate investigations
All neonates are screened clinically (Barlow and Ortolani tests)
at birth and at 6 weeks
Ultrasound is used as a selective screening test in ‘at-risk’
babies
Radiography is useful from 4 months onwards
Older children present with a limp and/or tiptoeing and a
lumbar lordosis in bilateral cases
(b)

a (c) Management The objective is to obtain a stable, congruous reduction of  the femoral head within the acetabulum while avoiding damage to the capital epiphysis (avascular necrosis [A VN]), which causes sti ff ness and proximal femoral deformity . Neonate Owing to the peripartum hormonal e ff ects many neonatal hips are unstable. Most stabilise spontaneously by 6 weeks. Hips that remain unstable or that are dislocated at rest are treated with harnesses or splints that obtain and maintain reduction with the hip abducted and flexed. Joint stability is monitored with ultrasound scanning. Most harnesses ( Figure 44.16 ) allow controlled mo vement while splints hold the hips more rigidly and may carry a greater risk of  A VN and femoral nerve palsy . If  the hips fail to relocate or stabilise, treatment should be discontinued. Christian Morin , contemporary , French paediatric orthopaedic surgeon. Heinrich Hilgenreiner , 1870–1954, German surgeon and orthopaedist. George Perkins , 1892–1980, Professor of  Surgery , St Thomas’ Hospital, London, UK, described signs by which to diagnose congenital dislocation of  the hip in 1928. a α α a b Infant Successful harness treatment is unusual after the age of 4–6 months. For the late-presenting hip or one that fails conservative treatment, an examination under anaesthetic may achieve a closed reduction. A psoas/adductor release can 

(c)
Figure 44.14
Ultrasound images of an infant hip.
(a)
Normal hip with
a high
angle and a Morin index of 50% (de
/f_i
ned as the percentage
of the femoral head covered by the acetabulum, i.e. the portion lying
below the horizontal red line).
(b)
Grossly dysplastic hip with a low
angle and a Morin index of <50%. This hip is likely to be unstable on
dynamic ultrasound scanning, i.e. Barlow positive.
(c)
A dislocated
hip joint (dislocated femoral head, red arrow; ‘empty’ acetabulum,
white arrow).
Figure 44.15
Anteroposterior pelvic radiograph showing Hilgenrein
-
er’s line (a) and Perkins’ line (b). The femoral head (ossi
/f_i
c nucleus) of
a normal hip lies in the inner lower quadrant. The right hip is normal;
the left hip has developmental dysplasia of the hip.

be performed if  the arthrogram suggests they are blocking reduction or limiting stability . Postoperatively , a spica cast maintains hip reduction. If  the hip is irreducible or can only be held reduced in an extreme position then treatment should be abandoned and an open reduction considered via a medial or anterior approach. Summary box 44.7 Management of early DDH /uni25CF /uni25CF /uni25CF /uni25CF Child A medial approach open reduction can be performed between 6 and 24 months of  age. An anterior approach to the hip (from 9–12 months of  age) allows for a simultaneous capsulorrhaphy . In the older child, a pelvic osteotomy may be required to reorientate the acetabulum, and femoral shortening or derotation osteotomies will improve stability ( Figure 44.17 Arnold Pavlik , 1902–1962, Czech orthopaedic surgeon, became famous mainly for the development of a functional, active method of treating developmental dysplasia of  the hip. Surgery is contraindicated in children over the age of  6–8 years in bilateral cases and the age of  8–10 years in unilateral cases ( Figure 44.18 ). Adolescent Hips are often dysplastic and subluxated. If the hip is reducible, the joint can be reconstructed with a combination of  pelvic and femoral osteotomies. For the irreducible hip, acetabular augmentation may reduce symptoms and delay the onset of degenerative change. ). 

Shoulder strap
Chest strap
Flexion strap
A
bduction strap
Leg strap
Figure 44.16
The anterior strap of the Pavlik harness controls hip
/f_l
exion, whereas the posterior strap limits adduction and encourages
abduction.
Many hips that are unstable in the
/f_i
rst 2–3 weeks of life
require no treatment as they improve spontaneously
Up to age 4–6 months, a harness or splint is effective
treatment
In older babies, closed reduction is often possible
For failed closed treatment, open surgical reduction is required
Figure 44.17
Anteroposterior pelvic radiograph showing acetabular
dysplasia with subluxation (developmental dysplasia of the hip) of the
left hip. This child presented at age 7 years.
Figure 44.18
Anteroposterior pelvic radiograph showing bilateral true
dislocations in a 9-year-old child; the decision was made not to offer
an operation. The pathology in these hips is different from that shown
in
Figure 44.17
.

Management of late-presenting DDH /uni25CF /uni25CF /uni25CF /uni25CF /uni25CF Secondary procedures and complications At follow-up, acetabular remodelling is assessed with the acetabular index or the centre–edge angle ( Figure 44.19 Surgery may be required for residual dysplasia or subluxation. A VN with trochanteric overgrowth causes a Trendelenburg limp: the outcome is poor ( Figure 44.20 ). Occasionally , a leg length di ff erence needs treatment. There is an increased risk of  osteoarthritis and hip arthroplasty later in life. 

The older the child, the more likely it is that they will require
surgery
Femoral osteotomy improves hip stability
Pelvic osteotomy redirects or reshapes the acetabulum
The potential for acetabular remodelling decreases after the
age of 3–4 years
Avascular necrosis is a risk with all DDH treatment