Developmental hip dislocation is the most common hip disorder in pediatric patients and one of the main diseases causing physical disability in children. It is characterized by partial or total dislocation of the femoral head from the hip joint in infants and young children, which can be manifested by unequal length of the lower limbs and popping of the hip joint under the age of 1 year, but in some cases there is no special manifestation and is only detected by doctors during routine physical examination of infants and young children. During the toddler period, the symptoms are limp or wobbly walking, commonly known as “duck walk”.
So far, the cause of developmental hip dislocation is still unclear.
The following factors may be related to the occurrence of hip dislocation.
1, genetic factors: some research statistics, children with a family history of developmental hip dislocation, the incidence of developmental hip dislocation in their families up to 20%-30%. And the incidence rate of girls is 6-8 times higher than that of boys.
2, hormonal factors: the mother needs to secrete a large amount of hormones during childbirth to make the pelvic ligaments relaxed and facilitate childbirth. Excess hormones may also cause the ligaments around the hip joint of the baby to relax, leading to hip dislocation.
3, fetal position factor: congenital hip dislocation occurs in breech delivery is 10 times higher than normal fetal position.
4. Inappropriate swaddling method: Tying the child’s lower limbs too tightly after birth, commonly known as “candle wrapping”, may lead to hip dislocation.
The infants with developmental hip dislocation do not have obvious signs at birth, which cannot attract parents’ attention, and most hospitals have not established a newborn physical examination and registration system, so the disease is often missed or delayed in diagnosis. Many children are diagnosed only after they are toddlers.
The best time to treat pediatric developmental hip dislocation is from birth to 6 months of age.
An infant should be promptly examined by a pediatric orthopedic surgeon if the following manifestations are noted during this age.
1. Asymmetrical height or number of skin folds on the hip, groin or thigh;
2, the infant bilateral lower limb activity imbalance, one side of the activity is less, the other side of the activity more; or one side of the pedal powerful, the other side of the power is small;
3.The appearance of the two lower limbs is asymmetrical, with different lengths or thicknesses;
Children over 1 year old should also seek medical consultation if they have walking limp and unequal lower limbs.
The aim of treatment for pediatric developmental hip dislocation is to obtain a stable central repositioning of the hip joint and avoid ischemic necrosis of the femoral head. If early diagnosis and treatment can be achieved, the treatment effect is satisfactory; if treatment is delayed, it will eventually lead to irreversible hip osteoarthritis and different degrees of disability.
(1) Birth ~ 6 months
Pavlik dressing device is preferred. If the hip is well repositioned after 3 weeks, continue to maintain it for 2~4 months and then replace the abductor brace for the next treatment.
(2) 7 months~18 months
As the age of the child increases, the weight and activity increase, the compliance and efficacy of using the dressing brace decreases, so the treatment plan also changes. The treatment plan will be changed to closed repositioning under anesthesia, hip herringbone cast or human plaster fixation, and generally after 4 months of plaster fixation, hip abduction brace fixation will be changed to ensure hip stability.
(3) 18 months~8 years old
The main surgical methods are: incision and repositioning, pelvic osteotomy and internal fixation of femoral osteotomy plate. Different surgical methods are chosen according to the condition. In order to make the best recovery for the child, the hip must be fixed in herringbone plaster after the operation, with long-term bed rest and regular X-ray review.
(4) Over 8 years old
Children older than 8 years old who seek treatment are difficult to operate, have many surgical complications, and have uncertain efficacy. The main purpose of treatment for unilateral patients is to restore the anatomy and function of the hip joint, create conditions for hip replacement, and equalize the length of the lower limbs to prevent secondary spinal deformities, and to choose incisional repositioning, pelvic and femoral osteotomy. In contrast, children with bilateral onset usually choose to wait until adulthood for hip replacement or no treatment. However, regardless of the method chosen, children over the age of 8 years are significantly more likely to develop early onset arthritis in adulthood.
Many parents are concerned about how to care for their children in a Pavlik dressing brace, an abduction brace and a post-surgical cast.
①Sleeping position: The brace needs to be worn 24 hours a day (except for bathing). The cast fixation needs to be maintained for 2-4 months and the child’s posture cannot be changed. When sleeping, the child’s legs cannot be put on the bed, and it is not very comfortable to cross them. It is recommended that parents use pillows, cushions and other soft objects to support the child’s legs, which will make the child more comfortable.
Bathing and changing clothes: When you need to give your child a bath or change clothes, you can take off the brace and after bathing or changing clothes, you can put the brace on your baby again according to the original method. If you find that the new brace is different from the previous one, you can ask the doctor to help you put it on again. Children with casts should not be bathed and should only be wiped with a towel. Keep the cast clean and prevent it from being impregnated and contaminated by water, urine and feces. In case of accidentally wetting the cast, use a hair dryer to blow dry with cold air.
③Posture of holding the child: After the brace or cast is worn, the traditional posture of holding the child is not suitable because the brace or cast may produce obstruction. It is better to cradle the child from the back while holding the child’s thighs with your hands.
The purpose is to ask the doctor to see if the brace is suitable and if some adjustments need to be made. After that, according to the doctor’s request, review the ultrasound or X-ray film regularly to observe the effect of treatment. In the case of plaster fixation, it is usually reviewed once a month.
⑤ Precautions after hip resetting: After resetting the hip joint dislocation, it does not mean that the treatment is over. Because the treatment of “developmental” hip dislocation is a long-term process, as the child develops, the hip joint may become dysplastic, subluxated or even dislocated, and must be reviewed every year until adulthood according to medical advice. If any of these problems occur, surgery may be required again. It is important to remember that after the developmental hip dislocation is cured, attention should be paid to the economical use of the joint. You can ride a bike and swim appropriately, but avoid participating in competitive sports such as basketball, soccer and long-distance running.