Congenital hip dislocation

orthopedics congenital hip dislocation

1. Congenital Hip Dislocation Dr. Amardeep K aur S aini(PT)

2. CHD This is a spontaneous dislocation of the hip occurring before, during or shortly after birth. In western countries, it is one of the commonest congenital disorder. It is uncommon in India and some other Asian countries, probably because of the culture of mother carrying the child on the side of her waist with the hips of the child abducted This position helps in reduction of an unstable hip, which otherwise would have dislocated. The general term “dysplastic hip” is sometimes used for these congenital malformations of the hip. Dr. Amardeep Kaur Saini(PT)

3. Aetiology Hereditary predisposition to joint laxity : Heredity related lax joints are predisposed to hip dislocation in some positions. Hormone induced joint laxity : CDH is 3-5 times more common in females. This may be due to the fact that the maternal relaxin (a ligament relaxing hormone in the mother during pregnancy) crosses the placental barrier to enter the foetus. If the hormonal environment of the foetus is a female, relaxin acts on the foetus's joints in the same way as it does on those of the mother. This produces joint laxity, and thus dislocation. Breech malposition : The incidence of an unstable hip is about 10 times more in newborns with breech presentation than those with vertex presentation. It is possible that in breech presentation the foetal legs are pressed inside the uterus in such a way that if the hip ligaments are lax, dislocation may occur. Dr. Amardeep Kaur Saini(PT)

4. Pathology 2 Types of Dysplastic hips; those dislocated at birth (classic CDH); those dislocatable after birth. The first are primarily due to a hereditary faulty development of the acetabulum, and are difficult to treat. The second are due to underlying joint laxity, with a precipitating factor causing the dislocation. Following changes are seen in a dislocated joint: Femoral head is dislocated upwards and laterally ; its epiphysis is small and ossifies late. Femoral neck is excessively anteverted. Acetabulum is shallow, with a steep sloping roof. Ligamentum teres is hypertrophied. Fibro-cartilaginous labrum of the acetabulum (limbus) may be folded into the cavity of the acetabulum (inverted limbus). Capsule of the hip joint is stretched. Muscles around the hip, especially the adductors, undergo adaptive shortening Dr. Amardeep Kaur Saini(PT)

5. Clinical Features CDH is more common in first born babies, more on the left, more common in females (M:F=1:5), bilateral in 20% cases. CDH may be detected at birth or soon after; sometimes not noticed until the child starts walking. • At birth : Routine screening of all newborns is necessary. The examining pediatrician may notice signs suggestive of a dislocated or a dislocatable hip, as discussed subsequently. • Early childhood : Sometimes, the child is brought because the parents have noticed an asymmetry of creases of the groin, limitation of movements of the affected hip, or a click every time the hip is moved. • Older child : CDH may become apparent once the child starts walking. Parents notice that the child walks with a ‘peculiar gait’ though there is no pain. On examination a CDH may be found to be the underlying cause. Dr. Amardeep Kaur Saini(PT)

6. EXAMINATION There may be limitation of hip abduction, asymmetry of groin creases or an audible click. Barlow's test : The test has two parts . In the first part, the surgeon faces the child's perineum. He grasps the upper part of each thigh, with his fingers behind on the greater trochanter and thumb in front. The child's knees are fully flexed and the hips flexed to a right angle. The hip is now gently adducted. As this is being done, gentle pressure is exerted by the examining hand in a proximal direction while the thumb tries to ‘push out’ the hip. As the femoral head rolls over the posterior lip of the acetabulum, it may, if dislocatable (but not, if dislocated) slip out of the acetabulum. One feels an abnormal posterior movement, appreciated by the fingers behind the greater trochanter. There may be a distinct ‘clunk’. If nothing happens, the hip may be normal or may already be dislocated; in the latter, second part of the test would be more relevant. Dr. Amardeep Kaur Saini(PT)

7. In the second part of the test, with the hips in 90° flexion and fully adducted, thighs are gently abducted. The examiner's hand tries to pull the hips while the fingers on the greater trochanter exert pressure in a forward direction, as if one is trying to put back a dislocated hip. If the hip is dislocated, either because of the first part of the test or if it was dislocated to start with, a ‘clunk’ will be heard and felt, indicating reduction of the dislocated hip. If nothing happens, the hip may be normal or it is an irreducible dislocation. In the latter case, there will be limitation of hip abduction. In a normal hip, it is possible to abduct the hips till the knee touches the couch.

8. Ortolani's test: This test is similar to the second part of Barlow's test. The hips and knees are held in a flexed position and gradually abducted. A ‘click of entrance’ will be felt as the femoral head slips into the acetabulum from the position of dislocation. In an older child, the following findings may be present: Limitation of abduction of the hip. Asymmetrical thigh folds . Higher buttock fold on the affected side. Galeazzi's sign : The level of the knees are compared in a child lying with hip flexed to 70°and knees flexed. There is a lowering of the knee on the affected side. Ortolani's test may be positive. Dr. Amardeep Kaur Saini(PT)

9. • Trendelenburg's test is positive : This test is performed in an older child. The child is asked to stand on the affected side. The opposite ASIS (that of the normal side) dips down. • The limb is short and slightly externally rotated. There is lordosis of the lumbar spine. • Telescopy positive : In a case of a dislocated hip, it will be possible to produce an up and down piston-like movement at the hip. This can be appreciated by feeling the movement of the greater trochanter under the fingers • A child with unilateral dislocation exhibits a typical gait in which the body lurches to the affected side as the child bears weight on it (Trendelenburg's gait). In a child with bilateral dislocation, there is alternate lurching on both sides (waddling gait). • Some hip pathologies mimicking CDH are: Coxa vara, posterior hip dislocation and paralytic hip dislocation and paralytic hip dislocation. Dr. Amardeep Kaur Saini(PT)

10. Radiological Features In a child below the age of 1 year, since the epiphysis of the femoral head is not ossified, it is difficult to diagnose a dislocated hip on plain X-rays . Von Rosen's view may help. Ultrasound examination is useful in early diagnosis at birth. In an older child, the following are the important X-ray findings: Delayed appearance* of the ossification centre of the head of the femur. Retarded development of the ossification centre of the head of the femur. • Sloping acetabulum. • Lateral and upward displacement of the ossification centre of the femoral head. Dr. Amardeep Kaur Saini(PT)

11. A break in Shenton's line Dr. Amardeep Kaur Saini(PT)

12. TREATMENT Principles of treatment : Aim is to achieve reduction of the head into the acetabulum, and maintain it until the hip becomes clinically stable and a 'round' acetabulum covers the head. In most cases, it is possible to reduce the hip by closed means; in some an open reduction is required. Once the head is inside the acetabulum, in younger children, under the mould-like effect of the head, it develops into a round acetabulum. If reduction has been delayed for more than 2 years, acetabular remodelling may not occur even after the head is reduced for a long time. Hence, in such cases, surgical reconstruction of the acetabulum may be required. Dr. Amardeep Kaur Saini(PT)

13. Methods of reduction: a) Closed manipulation : It is sometimes possible in younger children to reduce the hip by gentle closed manipulation under general anesthesia. b) In unilateral cases, reduction can be attempted till 10 years of age and till 8 years in bilateral cases c) Traction followed by closed manipulation: In cases where the manipulative reduction requires a great deal of force or if it fails, the hip is kept in traction for some time, and is progressively abducted. As this is done, it may be possible to reduce the femoral head easily under general anesthesia. An adductor tenotomy is often necessary in some cases to allow the hip to be fully abducted. d) Open reduction : This is indicated if closed reduction fails. Reasons of failure of closed reduction could be the presence of fibro-fatty tissue in the acetabulum or a fold of capsule and acetabular labrum (inverted limbus) between the femoral head and the superior part of the acetabulum. In such situations, the hip is exposed, the soft tissues obstructing the head excised or released, and the head repositioned in the acetabulum. Dr. Amardeep Kaur Saini(PT)

14. Maintenance of reduction : Once the hip has been reduced by closed or open methods, following methods may be used for maintaining the head inside the acetabulum. a) Plaster cast : A frog leg or Bachelor's cast. b) Splint : Some form of splint such as Von Rosen's splint. External splints can be removed once the acetabulum develops to a round shape. The hip is now mobilized, and kept under observation for a period of 2-3 years for any recurrence. Dr. Amardeep Kaur Saini(PT)

15. Acetabular reconstruction procedures : a) Salter's osteotomy : This is an osteotomy of the iliac bone, above the acetabulum. The roof of the acetabulum is rotated with the fulcrum at the pubic symphysis, so that the acetabulum becomes more horizontal, and thus covers the head. b) Chiari's pelvic displacement osteotomy : The iliac bone is divided almost transversely immediately above the acetabulum, and the lower fragment (bearing the acetabulum) is displaced medially. The margin of the upper fragment provides additional depth to the acetabulum. c) Pemberton's pericapsular osteotomy : A curved osteotomy as shown in this is made. The roof of the acetabulum is deflected downwards over the femoral head, with the fulcrum at the triradiate cartilage of the acetabulum. In some cases, reduction of the hip may be possible only in extreme abduction or internal rotation of the thigh. In such cases a varus derotation osteotomy is done at the sub-trochanteric region. The distal fragment is realigned and the osteotomy fixed with a plate. Dr. Amardeep Kaur Saini(PT)

16. Dr. Amardeep Kaur Saini(PT)

17. Treatment Plan Treatment varies according to the age at which the patient presents. this has been divided into four groups on the basis of age of the patient: • Birth to 6 months : The femoral head is reduced into the acetabulum by closed manipulation, and maintained with plaster cast or splint. • 6 months to 6 years : It may be possible up to 2 years to reduce the head into the acetabulum by closed methods. After 2 years, it is difficult and also unwise to attempt closed reduction. This is because, when the head has been out for some time, the soft tissues around the hip become tight. Such a hip, if reduced forcibly into the acetabulum, develops avascular necrosis of the femoral head. In these cases, reduction is achieved by open methods, and an additional femoral shortening may be required. In older children, an acetabular reconstruction may be performed at the same time or later. Salter's osteotomy is preferred by most surgeons. Dr. Amardeep Kaur Saini(PT)

18. • 6-10 years: The first point to be decided in children at this age is whether or not to treat the dislocation at all. No treatment may be indicated for children with bilateral dislocations because of the following reasons: • The limp is less noticeable. • Although having some posture and gait abnormalities, these patients tend to live normal lives until their 40's or 50's. • Results of treatment are unpredictable and a series of operations may be required. • In unilateral cases, an attempt at open reduction with reconstruction of the acetabulum may be made. A derotation osteotomy is needed in most cases. • 11 years onwards: Indication for treatment in these patients is pain. If only one hip is affected, a total hip replacement may be practical once adulthood is reached. Sometimes, arthrodesis of the hip may be a reasonable choice. Dr. Amardeep Kaur Saini(PT)

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