Overview
Definition:
Developmental Dysplasia of the Hip (DDH) is a spectrum of abnormalities in the acetabulum and femoral head, leading to instability and potential dislocation
It encompasses conditions ranging from acetabular dysplasia to complete dislocation of the hip joint.
Epidemiology:
DDH affects approximately 1-3 per 1000 live births in Caucasian populations, with a higher incidence in females (5:1 ratio)
Risk factors include breech presentation, oligohydramnios, firstborn status, family history of DDH, and certain genetic syndromes (e.g., Ehlers-Danlos, Down syndrome).
Clinical Significance:
Early diagnosis and treatment of DDH are crucial to prevent long-term sequelae such as avascular necrosis of the femoral head, osteoarthritis, limp, and chronic pain
Effective screening and management can lead to excellent functional outcomes.
Clinical Presentation
Symptoms:
In infants, symptoms may not be apparent
Parents may report asymmetry in leg length or thigh creases
Older children may present with a limp, waddling gait, or pain in the hip or knee.
Signs:
Key physical examination findings in infants include: Asymmetrical thigh folds
Unequal gluteal folds
Unequal knee heights (Allis sign)
Limited hip abduction (especially in flexion)
Positive Barlow's sign (for instability)
Positive Ortolani's sign (for reduction of a dislocated hip)
In older children, signs may include a Trendelenburg gait and pain on palpation of the hip.
Diagnostic Criteria:
There are no strict numerical diagnostic criteria for DDH
diagnosis relies on a combination of clinical suspicion, physical examination findings, and imaging
Pavlik harness is indicated for stable hips with >20 degrees of dysplasia or unstable hips in infants <6 months
Surgical intervention is considered for older infants or failed conservative management.
Diagnostic Approach
History Taking:
Key history points to elicit include: Gestational history (breech presentation, oligohydramnios)
Birth history (assisted delivery, prematurity)
Family history of DDH or hip problems
Previous assessment of hip stability
Presence of genetic syndromes
Any parental concerns about asymmetry or gait.
Physical Examination:
A systematic physical examination of the infant hip is essential
This includes: Assessing hip range of motion, particularly abduction in flexion
Performing the Barlow and Ortolani maneuvers
Checking for leg length discrepancy (Galeazzi sign)
Observing gait if the child is ambulant
Examining the spine for associated anomalies.
Investigations:
For infants up to 6 months, ultrasound of the hip is the investigation of choice
It assesses the relationship between the femoral head and acetabulum, and the Graf classification helps quantify dysplasia
For infants older than 6 months or when ultrasound is equivocal, a plain radiograph of the pelvis (AP and frog-leg lateral views) is used
Key radiographic measurements include the acetabular index, Shenton's line, and the center-edge angle
Magnetic Resonance Imaging (MRI) may be used in select cases.
Differential Diagnosis:
Conditions to consider in the differential diagnosis of DDH include: Transient synovitis of the hip
Septic arthritis of the hip
Legg-Calvé-Perthes disease
Slipped capital femoral epiphysis (in older children)
Femoral nerve palsy
Neuromuscular conditions causing hip instability
Contractures or spasticity leading to apparent asymmetry.
Management
Initial Management:
In neonates and infants with suspected DDH, the initial management is based on the age of the infant and the severity of dysplasia
For infants under 6 months with unstable hips or significant dysplasia, the Pavlik harness is the mainstay of treatment
Proper application and regular follow-up are critical.
Medical Management:
Medical management is primarily conservative, focusing on maintaining the hip in a reduced position to promote normal development
The Pavlik harness is a dynamic brace that maintains flexion and abduction, allowing for controlled movement
Continuous wear, typically for 6-12 weeks, is usually required.
Surgical Management:
Surgical management is indicated for DDH that is irreducible, neglected, or has failed conservative treatment
Options include: Closed reduction with spica casting (for younger infants)
Open reduction of the hip (if closed reduction fails or if there are significant soft tissue contractures)
Pelvic osteotomy (e.g., Pemberton, Salter, Dega) to improve acetabular coverage
Femoral osteotomy may be combined with pelvic osteotomy.
Supportive Care:
Supportive care involves educating parents on harness care, skin hygiene, and signs of complications (e.g., nerve palsy, skin breakdown)
Regular clinical and radiological follow-up is essential to monitor progress and adjust treatment as needed
Physiotherapy may be required post-treatment to regain full range of motion and strength.
Complications
Early Complications:
Early complications of DDH management include: Pavlik harness-related issues: skin irritation, pressure sores, femoral nerve palsy (rare), avascular necrosis (rare, often due to overtreatment or improper positioning).
Late Complications:
Late complications, especially if DDH is untreated or inadequately managed, can include: Osteoarthritis
Avascular necrosis of the femoral head
Irreparable joint damage
Chronic hip pain
Limp and gait abnormalities
Hip dislocation recurrence.
Prevention Strategies:
Prevention strategies focus on early detection through routine screening
This includes: Clinical examination at birth and at subsequent well-child visits
Universal ultrasound screening in high-risk populations or based on local protocols
Promoting safe swaddling practices to avoid excessive hip adduction and extension
Educating healthcare providers on the importance of early diagnosis.
Prognosis
Factors Affecting Prognosis:
The prognosis of DDH is generally excellent when diagnosed and treated early
Factors influencing outcome include: Age at diagnosis
Severity of dysplasia
Adequacy of reduction and stability
Adherence to treatment
Presence of associated anomalies.
Outcomes:
With early and appropriate treatment, most infants achieve a stable hip with normal function and morphology
Late diagnosis or treatment can lead to poorer outcomes, including early-onset osteoarthritis and the need for reconstructive surgery
Approximately 80-90% of infants treated with the Pavlik harness before 3 months of age achieve a satisfactory reduction.
Follow Up:
Long-term follow-up is crucial, especially for those with treated DDH or significant dysplasia
This typically involves clinical assessments and serial radiographs until skeletal maturity to monitor for recurrence or the development of late complications like osteoarthritis
Standard follow-up includes checks at 6 weeks, 3 months, 6 months, 1 year, and annually thereafter as clinically indicated.
Key Points
Exam Focus:
Barlow's test assesses for provocation of dislocation
Ortolani's test assesses for reduction of a dislocated hip
Ultrasound is preferred for screening infants < 6 months
Radiographs are used for infants > 6 months
Pavlik harness is the primary treatment for infants < 6 months with unstable hips or significant dysplasia.
Clinical Pearls:
Always perform hip examination in a relaxed infant, preferably on a warm surface
Remember that a "clunk" on Ortolani's maneuver can be from a tight labrum or ligament, not necessarily a dislocated hip
Monitor for signs of skin breakdown and neurovascular compromise with harness use.
Common Mistakes:
Over-reliance on a single physical exam finding without imaging
Delaying imaging in a persistently unstable or painful hip
Improper application or prolonged immobilization with the Pavlik harness, leading to complications
Failing to follow up adequately, missing early signs of treatment failure or recurrence.