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at is congenital dislocation of the hip?
Congenital dislocation of the hip (CDH) is a condition found from birth where the ball and socket joint at the hip does not stay locked together as it should.
The top of the thigh-bone (or femur) normally has a ball shape which rolls around within a “cup” shaped socket in the pelvic bones. This allows the leg to move through a large circle at the hip.
In some babies the shape of the ball or socket has not developed properly, which means that they easily become detached – the socket may be very shallow or small for example.
Alternatively the ligaments which usually hold the ball and socket together may be loose or stretched.
As a result the ball part of the joint may come out of the socket completely, or simply be looser than it is. If this isn’t corrected the child may grow up with legs of different lengths and an abnormal gait, causing pain and the early development of osteoarthritis of the hip joint. So, while congenital dislocation of the hip isn't a life-threatening problem - and babies are unlikely to experience pain because they're not putting any weight on the joint - it can have long-term complications, especially if not treated early.
The condition is also now known as developmental dysplasia of the hip (DDH) although many people still know it as CDH. This new name reflects current understanding of it as an ongoing problem related to abnormal development of the hip. Also, the condition appears in various ways and is not always present at birth (hence not always ‘congenital’). DDH covers a range of developmental disorders of the hip, from mild abnormalities to severe dislocation.
Top
Symptoms
All newborn babies have their hips checked for DDH within a few days of birth and at six weeks, so that treatment can be started early if necessary, long before damage occurs.
One of the first things doctors ask parents about or check for is a clicking sound when the baby's legs are moved apart. This sound occurs when the ball slips out of the socket – a sign that there is a problem. With a full dislocation, the leg "rides up" so it’s shorter than the other one.
If tests don't pick up the problem, the dislocation can cause symptoms when the baby starts to walk. These may include:
Top
Causes and risk factors
More than one in 100 newborn babies has 'unstable' hips (which can be dislocated by the doctor during testing), but only one in ten of these is a true dislocation that requires more intensive treatment. In some babies, the socket fails to develop as it should during the early months and years of life and DDH only therefore becomes apparent after the newborn period.
Girls are affected six times more often than boys and, rather strangely, the left hip is four times more likely to be affected than the right (this is thought to be a result of the baby's position in the womb). In a third of cases, both hips are affected.
All newborn babies should have their hips checked by a doctor who knows exactly what to look and feel for.
An ultrasound scan is often used to confirm the diagnosis, and it has been suggested that this should be used to screen all babies for DDH. X-rays of the hips may be useful in older children, and sometimes more sophisticated imaging such as CT or MRI may be used.
Top
Treatment and recovery
The recommended treatment depends on the extent of dislocation and the shape of the hip socket.
In newborn babies, holding the hip flexed and abducted (with the leg pulled up and turned out) for one or two months may be all that is needed. This keeps the top of the femur in the right position while the ligaments and bones grow and strengthen around it. This position is maintained by the use of a brace, splint or harness - devices known as orthoses and fitted by health specialists (known as orthotists). Occasionally, a newborn baby is put into double or even triple nappies for two to three weeks until orthoses fit them, but this strategy is controversial.
Surgery to align the top of the femur and the hip is sometimes necessary especially when DDH is diagnosed in children over the age of two.
Congenital dislocation of the hip (CDH) is a condition found from birth where the ball and socket joint at the hip does not stay locked together as it should.
The top of the thigh-bone (or femur) normally has a ball shape which rolls around within a “cup” shaped socket in the pelvic bones. This allows the leg to move through a large circle at the hip.
In some babies the shape of the ball or socket has not developed properly, which means that they easily become detached – the socket may be very shallow or small for example.
Alternatively the ligaments which usually hold the ball and socket together may be loose or stretched.
As a result the ball part of the joint may come out of the socket completely, or simply be looser than it is. If this isn’t corrected the child may grow up with legs of different lengths and an abnormal gait, causing pain and the early development of osteoarthritis of the hip joint. So, while congenital dislocation of the hip isn't a life-threatening problem - and babies are unlikely to experience pain because they're not putting any weight on the joint - it can have long-term complications, especially if not treated early.
The condition is also now known as developmental dysplasia of the hip (DDH) although many people still know it as CDH. This new name reflects current understanding of it as an ongoing problem related to abnormal development of the hip. Also, the condition appears in various ways and is not always present at birth (hence not always ‘congenital’). DDH covers a range of developmental disorders of the hip, from mild abnormalities to severe dislocation.
Top
Symptoms
All newborn babies have their hips checked for DDH within a few days of birth and at six weeks, so that treatment can be started early if necessary, long before damage occurs.
One of the first things doctors ask parents about or check for is a clicking sound when the baby's legs are moved apart. This sound occurs when the ball slips out of the socket – a sign that there is a problem. With a full dislocation, the leg "rides up" so it’s shorter than the other one.
If tests don't pick up the problem, the dislocation can cause symptoms when the baby starts to walk. These may include:
- Delayed walking
- Abnormal waddling gait (the affected leg is shorter)
- Asymmetrical thigh creases (an extra crease on the affected side)
- Inability to abduct the affected hip fully (move the leg out away from the body)
Top
Causes and risk factors
More than one in 100 newborn babies has 'unstable' hips (which can be dislocated by the doctor during testing), but only one in ten of these is a true dislocation that requires more intensive treatment. In some babies, the socket fails to develop as it should during the early months and years of life and DDH only therefore becomes apparent after the newborn period.
Girls are affected six times more often than boys and, rather strangely, the left hip is four times more likely to be affected than the right (this is thought to be a result of the baby's position in the womb). In a third of cases, both hips are affected.
All newborn babies should have their hips checked by a doctor who knows exactly what to look and feel for.
An ultrasound scan is often used to confirm the diagnosis, and it has been suggested that this should be used to screen all babies for DDH. X-rays of the hips may be useful in older children, and sometimes more sophisticated imaging such as CT or MRI may be used.
Top
Treatment and recovery
The recommended treatment depends on the extent of dislocation and the shape of the hip socket.
In newborn babies, holding the hip flexed and abducted (with the leg pulled up and turned out) for one or two months may be all that is needed. This keeps the top of the femur in the right position while the ligaments and bones grow and strengthen around it. This position is maintained by the use of a brace, splint or harness - devices known as orthoses and fitted by health specialists (known as orthotists). Occasionally, a newborn baby is put into double or even triple nappies for two to three weeks until orthoses fit them, but this strategy is controversial.
Surgery to align the top of the femur and the hip is sometimes necessary especially when DDH is diagnosed in children over the age of two.