Recently, Brian Loh published a paper in the Australian Journal of General Practice on the management of infant and toddler developmental dysplasia of the hip (DDH).
The full article can be read here: https://www1.racgp.org.au/ajgp/2021/april/infant-and-toddler-developmental-dysplasia-of-the
The following is a precis of the article, focusing on the key watch points for the diagnosis and management of DDH.
GPs and MCHNs are key in early detection of DDH.
The human acetabulum (hip cup) is shallower at birth than at any other time in development. After birth, it is the ball in the cup of the joint that promotes good hip development. The head of femur (ball) must be enlocated in the acetabulum to encourage the acetabulum to deepen which in turn increases the sphericity of the femoral head. If the head of femur is not enlocated snuggly in the acetabulum, the hip fails to develop properly and the wide spectrum pathology that ensues is called DDH.
In newborns, hip dysplasia can range from instability to acetabular dysplasia to subluxation or dislocation of the hip. Most cases of instability resolve by 12 weeks, more severe presentations will need intervention to ensure good hip development.
Risk factors to be aware of for DDH are:
• Female sex
• Breech delivery
• Intrauterine packaging deformities e.g plagiocephaly, foot deformities or torticollis
• Family history of DDH
Physical examination may reveal:
• Instability found via Barlow and Ortolani’s tests
• Limited abduction
• Deep, uneven gluteal crease
• Leg length discrepancy
• Waddling gait after walking age
If risk factors are present in a child aged under 6 months then ultrasound screening warranted, preferably by a paediatric ultrasound service. All babies who had a breech presentation should also be screened with an ultrasound at 6 weeks.
A child over 6 months old with risk factors for DDH should be screened with an xray (Anterioposterior pelvis with leg in extended position and “frog leg” views.)
Children over 12 months of age who have previously been investigated for DDH should have a surveillance anterioposterior pelvis xray, because of the incidence of late presenting DDH.
Referral to a paediatric orthopaedic surgeon should be made if there is:
• an abnormal physical examination
• an abnormal ultrasound or xray
The goal of all DDH treatment is to obtain a concentric reduction where the femoral head is docked nicely in the acetabulum. This is needed to have a well-functioning hip at skeletal maturity.
Once a hip is reduced it is important to maintain this position until the hip is stable and is developmentally normalising. Treatment options include:
• Hip abduction bracing: Used in children less than 4 months with an unstable hip. In children with dislocated hips it is imperative that the child is reviewed in 2 weeks after brace application to ensure concentric reduction.
• Closed reduction, arthrography and spica cast application: If hip abduction bracing fails or if the child presents at an older age, a gentle closed reduction under general anaesthetic with spica cast immobilisation is the next option. Adductor muscle contractures can prevent reduction and this can be treated with a proximal tenotomy of the adductor longus. After reduction is achieved, a plaster cast is applied (Spica cast) to hold the hip in the optimal position and then the reduction checked via MRI.
• Open reduction is used when closed reduction has failed or concentric reduction cannot be achieved possibly due to intraarticular obstacles.
• Femoral osteotomy – if the shape of the femur prevents concentric reduction
• Acetabular osteotomy – if the shape of the acetabulum prevents concentric reduction
The diagnosis and management of DDH has come a long way over. However, prompt diagnosis and management are the most important factors related to outcome and an awareness that DDH can be present in asymptomatic patients in through infancy and childhood.