Developmental dysplasia of the hips (DDH) and congenital foot deformities

The incidence of late diagnosed DDH remains to be 1.28/100 despite a targeted hip screening programme. Reported incidence in the UK is 1.2/1000 live births.

There is a 4-fold increase in females due to increased ligamentous laxity caused by circulating hormone, relaxin. The left hip is involved in 60% of cases (right 20%, bilateral 20%) which may be due to the anterior position of the occiput and limited space for abduction³.

Universal vs targeted hip screening

There is controversy over the use of universal ultrasound in diagnosis of DDH as more than 90% of abnormalities detected resolve on follow-up. A Cochrane review of screening programmes for DDH (2011) concluded there was insufficient evidence to give recommendations. There was inconsistent evidence that universal ultrasound increased treatment rates compared with targeted screening. However, neither strategy was shown to reduce late complications of DDH including late diagnosis or surgery.⁴ More recently however universal screening has been shown to reduce the risk of late presentation of DDH and the need for surgical intervention (as well as reducing number of surgical procedures required.) Therefore, in Scotland, hip screening is done using targeted risk factors, clinical assessment and targeted hip ultrasound.

Infants with the following risk factors should be referred for a hip ultrasound:

Breech presentation
This exerts mechanical forces on the developing hip joint with frank breech being at highest risk.⁵ (see high risk infant criteria for more details)

Family history of DDH in first degree relative.
The incidence of DDH increases 12-fold in affected first degree relatives.⁶ If there is one affected sibling the risk is 60 per 1000 and increases to 120 per 1000 for an affected parent⁷

Fixed foot deformities
Fixed foot deformities have been shown in studies to be associated with a higher risk of DDH ^8,9 

Multiple pregnancies, where any of the above risk factors are present. This is because if one baby meets criteria, it can sometimes be difficult to accurately assess which baby was affected.

There is insufficient evidence to support the inclusion of torticollis or oligohydramnios as these have not been proven to increase the risk of “nonsyndromic” DDH.^10,11

In general, risk factors are poor predictors of DDH. Female sex, alone, without other known risk factors, accounts for 75% of DDH ¹². This emphasizes the importance of a careful physical examination of all infants in detecting DDH.¹³

The neonatal clinical hip examination is part of the routine new born examination. All hip joints should be examined in a systematic manner using the look, feel, move approach ideally within 24 hours and certainly before 72 hours after birth¹⁴. All hips should be re-examined at 6-8 weeks of age for DDH (usually in primary care).

History Before examination, maternal obstetric history, baby’s family history and hip risk factors should be reviewed. Family history of DDH, breech presentation after 36 weeks gestation or fixed foot deformity, are triggers for a hip ultrasound (see risk factors for screening).

Examination Clinical assessment involves an inspection (look), palpation (feel) and (move)ment approach.

‘Look’: Inspection is important to assess for symmetry of leg length and gluteals.

‘Feel’ – evaluated by flexing the hips and knees. Unequal knee lengths (Galeazzi sign), is a sign of a dislocated hip. A dislocated hip is a more common cause of leg length discrepancy than any other causes.
Leg length discrepancy in a neonate is a trigger for a hip ultrasound.

Figure 2¹⁵

‘Move’
Gentle abduction test
The hips should be fully flexed and abducted together, to detect any difference between the sides. The examiner's middle fingers are placed on the greater trochanter with the flexed legs contained in the palms. The thumbs rest on the inner side of the thighs opposite the lesser trochanter. Even slight limitation of abduction may be significant, indicating a hip that is starting to subluxate. Asymmetry or reduction of hip abduction of the hip in a neonate is a trigger for a hip ultrasound.

Ortolani and Barlow’s manoeuvres are then performed with the pelvis stabilised by the opposite hand.
Ortolani is a test of hip joint reducibility and Barlow’s for dislocatability. Examine one hip at a time. Ideally the baby should be relaxed and the family reassured that the test is not painful.

Ortolani’s test returns a posteriorly dislocated femoral head back into the acetabulum. It is performed by holding the hip with the thumb over the inner thigh, the middle finger over the greater trochanter and abducting the hip. An abnormal Ortolani test is when the greater trochanter is felt to move forward as the hip reduces into the acetabulum. It must be stressed that reduction of the hip almost never produces an audible sound.

In Barlow’s test, a similar hand position is used and the hips are flexed. Posterior pressure is applied in the line of the femur with the hips in neutral ab/adduction. An abnormal test is when the femur is felt to move backwards relative to the fixed pelvis, and indicates hip instability.

1. H - History
Patients with the following risk factors and a normal clinical hip examination should undergo hip ultrasound within 4-6 weeks corrected gestational age.

• Breech presentation at or after 36 completed weeks of pregnancy, irrespective of presentation at birth or mode of delivery. This includes breech babies who have had a successful external cephalic version (ECV).
• Breech presentation at delivery if ≥ 28 weeks gestation.
• Positive family history in first degree relative
• Foot deformities – calcaneovalgus, fixed talipes equinovarus
• In multiple births, where any of these risk factors are present, all babies in the pregnancy should be referred for a hip USS.¹⁰

2. Abnormal Clinical Examination in the neonatal period

I – Inspection – asymmetrical groin creases, leg length discrepancy
P – Palpation – Asymmetrical hip abduction
S – Stability – Either an abnormal Barlow (dislocatable) or Ortolani (dislocated) test – findings will need to be confirmed by an experienced team member. If confirmed, contact the local orthopaedic team-on-call prior to discharge.

NB: Ligamentous clicks without instability (only if outcome unclear)
There is limited evidence in the literature to support hip ultrasound screening in isolated clicky hips without instabiltiy.^1,16 However, it can be difficult to differentiate between a clicky hip and an unstable hip, by a non-expert examiner. Therefore, ligamentous clicks should be examined by experienced middle grade staff. If screening outcome is still unclear, then an ultrasound should be performed.

Table 1 ¹⁴

Ultrasound
The ultrasound is a well-established tool for detecting DDH and evaluation of babies with an abnormal examination. The position of the femoral head, acetabular coverage and stability on dynamic testing can be assessed.

The Graf method is used for joint evaluation, with 3 bony landmarks: 1. lower limb 2. plane and 3. labrum. The condro-osseous border should also be on. Both hips are evaluated.

This method classifies joints as:

• Type I – normal
• Type IIa - if alpha angle appropriate for age the Sonographer/Orthopaedics organises a rescan in 3-4 weeks.
• Type IIb - if alpha angle not appropriate for age inform on call paediatric orthopaedic team*
• Type IIc - inform on call paediatric orthopaedic team*
• Type IId – inform on call paediatric orthopaedic team*
• Type III – inform on call paediatric orthopaedic team*
• Type IV – inform on call paediatric orthopaedic team*

*see specific local pathway below

Table 2^16,17

X-rays
X-rays before 4 months have higher false negative rate as in the first few months of life, the bones are predominately cartilaginous which makes x-rays unreliable in assessing the hip structure. When the ossification centre of the femoral head appears after 4-6 months, x-ray may be a useful tool as abnormalities are more apparent.

The aims of early DDH treatment are to achieve stable reduction without complications. The splints used vary. The Pavlik harness is the most commonly used treatment and has a success rate of 95% in dysplastic or subluxed joints. It must be kept on at all times and will be monitored by the orthopaedic team.

 Figure 6 Pavlik Harness (with limited hip abduction on the right)¹⁸ 

The potential complications of splinting are avascular necrosis of the femoral head and rarely, irreducible
dislocation, femoral nerve or accessory nerve palsies²¹.

Surgical reduction
Indications: failure of conservative management (splinting) or late diagnosis 6-18 months. In older infants, open reduction is the main stay of treatment.

Parental advice

• Parental Advice Leaflet from STEPS charity – Hip Health
• Parental Advice Leaflet from STEPS charity – Caring for a baby in a Pavlik harness
• NHSGGC Leaflet about the Hip screening program

Calcaneovalgus

The mild form is present in 30 to 40% of neonates. The ankle is dorsiflexed so that the foot is positioned against the anterior aspect of the leg. It is usually a positional deformity with easy passive correction.
The vast majority of babies will show spontaneous resolution.
Gentle stretching of the foot into plantarflexion and inversion can be helpful although the majority resolve by 3 to 6 months.^19,20

Fixed Talipes Equinovarus (Clubfoot)

Common disorder affecting 1-2/1000 population. Male: female ratio is 2:1. Up to 50% of cases are bilateral. It can be diagnosed antenatally. The foot is turned inward and downward and the forefoot is short, wide, adducted and supinated. The sole of the foot points medially. The involved foot, calf, and leg may be smaller and shorter than the normal side. Should be confirmed by an experienced paediatric team member and referral to local clubfoot service should be made prior to discharge. Gold standard of treatment is the Ponseti method of serial casting and manipulation (successful in >90% of cases).^20,21

Positional Talipes Equinovarus

The involved hind foot is in correctable equinovarus (foot is turned inward & downward but easily correctable). Can be easily corrected by pushing the foot up into a normal position. If unsure, infant should undergo senior paediatric review to confirm positional talipes and referral to physiotherapy. An advice leaflet is available from the STEPS charity (see below)

Parental Advice

• Parental Advice leaflet from STEPS charity – Talipes / Club foot
• Parental advice leaflet from STEPS charity - Positional Talipes / Club Foot

RHCG/PRM Orthopaedic Referral Letter (Word doc)

Clyde Orthopaedic Referral Letter (Word doc) (form updated September 2022)