Chapter 46- The Child's Hip Flashcards
In a child with a trendelenberg limp, what is the limp diagnostic calendar
- 1-5 years- missed congenital dislocation of the hip
- 5-10 years- perthes disease
- 10-15 years- slipped upper femoral epiphyses
- septic arthritis and transient synovitis of the hip can present at any age
What is developmental dysplasia of the hip
- idiopathic hip dysplasia
- it includes dislocation at birth and acetabular dysplasia where the hip is located, patient becomes symptomatic later in life because acetabulum has not developed normally
Ligamentous laxity contributes to developmental dysplasia of the hip. What causes ligamentous laxity
- sensitivity to female perinatal hormone relaxin
Mechanical factors contributing to developemental dysplasia of the hip
- in utero: increased incidence in Breech, first born and oligohydramnios
- Postnatal: swaddling eg by native americans
Pathology of developmental dysplasia of the hip
Hip dislocates supero-laterally and capsule develops in an hourglass deformity with the inferior capusle being the main obstruction to reduction. Acetabulum becomes more dysplastic with deficient antero-lateral cove.
Describe the tests done in the neonatal period to test for hip instability
- Ortolani: dislocated hip relocates with abduction of the hip
- Barlow: hip located but unstable and dislocates with adduction
What test is indicated in patients at high risk for developmental dysplasia of the hip and when is the ideal time for this test
- Ultrasound (more sensitive than clinical exam)
- Ideal time is at 6 weeks
Describe a patient at high risk for developmental dysplasia of the hip
- positive family history
- First born
- Breech
- Barlow positive hip
- any ‘suspicious’ hip
Describe the AP pelvis radiograph in developmental dysplasia of the hip
- Femoral epiphyses only apparent at 6 months, therefore special lines are required to show superolateral dislocation.
- Shenton’s line (joining inferior femoral neck with inferior pubic ramus) is broken
- Metaphysis of femoral neck lies laterally to a line drawn from the lateral border of the acetabulum
What may an untreated dislocated hip in a child eventually lead to
- Adequate treatment prevents a trendelenburg, short leg limp
- Stiff, painful hip due to avascular necrosis is often due to treatment only
Treatment of dislocation based on age?
- <6 months: Pavlik harness
- 6- 18 months: traction, closed reduction and spica
- > 18 m: Open reduction, pelvic osteotomy +- femoral osteotomy
What position does the pavlik harness hold the hips in?
-Hips in flexion and abduction but allows mobility
What is the complication of treatment of developmental dysplasia of the hip
- Avascular necrosis
- Caused by splinting of the hip in more than 40 degrees of abduction in the pavlik harness or spica. or with a tight open reduction (femoral shortening reduces the chance of avascular necrosis
Average age of presentation of SUFE
- Boys: 14
- Girls: 12
Main complications of SUFE
- Avascular necrosis
- Chondrolysis
What are the current theories of the cause of SUFE
- Hormonal: Sex hormones close the growth plate and growth hormone increases the thickness of the growth plate, and therefore makes it weaker
- Retroversion: Increased retroversion of the femoral neck predisposes the femoral head to slip posteriorly
- Trauma: repetitive trauma in obese patients acting of an abnormal growth plate could be a factor
- Hereditary
Definite causes of SUFE
- Primary hypothyroidism
- Pituitary tumours
- Hypogonadism
- Renal rickets
Clinical presentation of SUFE
- Hip pain often referred to the knee
- 50 percent are overweight
- Antalgic, trendelenberg and possibly short limb limp
- decreased abduction and internal rotation of the hip
- Hip goes into external rotation when flexing because anteriorly displaced femoral neck blocks internal rotation
- Acute slip: duration of symptoms less than 3 weeks
- Chronic slip: Duration more than three weeks
- Acute on chronic: sudden exacerbation of chronic symptoms
Stable vs unstable SUFE
- Stable: patient can weight bear with or without crutches. no AVN
- Unstable: cannot weight bear with or without crutches. 10 percent develop AVN
Findings on radiograph in SUFE (Ap and frog lateral)
- AP: minimal slip shows a widened and irregular physis. An established slip has a positve Trethowan’s sign: a line along the superior aspect of the neck remains superior to the head instead of going through it.
- Lateral radiograph: Positive Capener’s sign: femoral head lies outside the acetabulum
How is the percentage slip determined in SUFE and how does this relate to the severity
- Percentage slip is determined on lateral view by the Wilson percentage method or the head shaft angle
- Mild: < 30% slip or 30 degrees
- Moderate: 30- 50 % slip or 30-60 degrees
- Severe: > 50 % slip or >60 degrees
Treatment of mild to moderate SUFE
Pinning in situ is achieved by one screw placed in the centre of the epiphyses and 90 degrees to the growth plate
Treatment of severe SUFE
-If slip is unpinnable, slow reduction of the hip with traction in abduction and internal rotation over a few days has a low incidence of AVN
What is Perthe’s disease
-Partial or total avascular necrosis of the femoral head, in contrast to other causes of AVN, the femoral head recovers
Etiology of perthes disease
- Recurrent infarction occurs
- Etiology is unknown
- Blood supply from 3-10 years is limited to the lateral retinacular vessel only, the metaphyseal vessels disappear after 2 years
- The lateral retinacular vessel is vulnerable to changes of pressure in the hip capsule
What are the three stages of Perthes disease
- Avascular stage: Femoral head can be normal. joint space is increased. Subchondral fracture occurs when trabeculae collapse. Finally the head becomes sclerotic
- Revascularisation phase: Dead bone is removed by ‘creeping substitution and the femoral head looks cystic and fragmented
- Healing stage: Subchondral ossification occurs. whole process up till now takes up to one year. the healing process is only completed after 2-4 years and the final shape of the head (spherical, oval or flat) becomes obvious at maturity
Clincal presentation of Perthes disease
- Antalgic and trendelenberg limp
- Decreased abduction and external rotation
How does one classify Perthes disease according to the Catterall groups?
1: anterior quarter
2: Anterior half (lateral pillar intact)
3: lateral three quarters (lateral pillar involved)
4: whole head involvement
What is the goal of treatment in Perthes disease
-Protect the femoral head during biologically plastic or soft stage (during avascular and revascularisation phases) and prevent it from becoming flat instead of spherical
Definitive treatment of Perthes ?
Includes:
- Containment: by abducting the hip the lateral pillar is protected by the acetabulum
- Movement for cartilage nutrition
- Some believe non weight bearing also plays a role
Conservative treatment of Perthes disease
-Abduction plasters or splints (weight bearing and non-weight bearing) for about one year until subchondral ossification occurs and deformity of the femoral head cannot occur
Surgical treatment of Perthes
- Pelvic Osteotomy: salter (<8), Chiari, Shelf
- Femoral osteotomy
Prognostic Factors of Perthes disease
- Age ( > 8 years)
- Lateral pillar involvement
