The term developmental hip dysplasia (DDH) is used instead of the term DKH (congenital hip dislocation), which was used until the last 15 years. The reason for this is that in babies with the disease, the majority of the hips are reduced in the neonatal period, but later on, semi-dislocation or dislocation develops after a while due to the insufficiency of the structures that should keep the femoral head reduced.
The explanation of the terms used in this regard is as follows:
Acetabular dysplasia: due to the congenital problem in the acetabulum, its development is inadequate and it does not cover the femoral head sufficiently.
Hip instability: due to the flexibility of the joint capsule and ligaments that must keep the femoral head in the acetabulum, the femoral head can be removed from the acetabulum with the Barlow maneuver. deterioration of the physiological relationship with the femur, development of semi-dislocation or dislocation
Semi-dislocation (subluxation): the contact between the femoral head and the acetabulum continues, although it decreases, but adequate coverage is not provided
Dislocation (luxation, dislocation) : loss of contact between the femoral head and acetabulum cartilage
As can be understood from the first paragraph of the topic, contact between the femoral head and acetabulum continues in most of the diseased babies in the newborn period, and joint dislocation gradually develops as the baby grows. For this reason, the use of the term DKD, which can be understood as if all the hips are dislocated from birth, is being abandoned.
Epidemiology:
The incidence of DKD in our country is not exactly known. Instability and dysplasia are seen in 1-2% of the newborn period, and 90% of these hips return to normal within the first 3 months under physiological conditions. In studies conducted around the world, DDH is reported to be 1-3 per thousand, although it varies by geography.
It is 4 times more common in girls than in boys. The left hip is affected in 60%, the right hip in 20%, and bilaterally in 20%.
Etiology:
The cause is not fully known and is thought to be multifactorial. Genetic characteristics are absolutely very important. If one of the parents has DDH, the risk is stated to be 12%, and if the sibling has DDH, the risk is stated to be 6%.
Factors that predispose to the development of DDH. :
Ligament laxity
Oligohydramnios
Breech presentation
First birth
Female gender
Family history
Use of swaddling
Pathological Anatomy:
Acetabulum loses its spherical structure covering the femoral head and becomes shallow. Femur. The sphericity of the head deteriorates in later periods. The longer the femoral head remains outside the acetabulum, the more changes in the acetabulum and femoral head increase. Femoral anteversion may be high.
Adaptive changes occur in the joint capsule, iliopsoas tendon, labrum, ligamentum teres and transverse acetabular ligament. The iliopsoas tendon shortens, pressing anteriorly on the joint capsule that extends laterally with the femoral head, causing the development of an hourglass appearance in the joint capsule.
Physical Examination:
All newborns should be evaluated for DDH by their family physician. First of all, risk factors are screened and risky babies are identified. Symmetry in the baby's leg movements is observed. Each hip should be evaluated individually. Both hips should normally be flexed and abducted. This position is called "frog position" and is necessary for the physiological development of the hips. Swaddling that disrupts this position of the hips, wrapping babies tightly and restricting movements, and extending the knees and hips will damage the development of the hips.
Abduction limitation: While the hips are flexed at 90 degrees, both hips are abducted. A difference of more than 20 degrees between abduction angles indicates unilateral abduction restriction, which is an important finding in terms of unilateral DDH.
Length difference: There is a difference between knee levels when the hips are flexed (Galeazzi test). , a difference between the knee levels when the feet are on the bed (Allis test) and a difference between the heels when the knees are extended should suggest that there may be DDH on the shorter side.
Pili asymmetry: when the hips are flexed or Although asymmetry between skin folds on the thigh when in extension is a finding that can also be seen in normal babies, it should be investigated for DDH. It should be done.
Ortolani test: The hip is abducted while it is flexed at 90 degrees. The femoral head is pushed into the acetabulum via the greater trochanter. Reduction of the femoral head indicates that the test is positive. A positive Ortolani test is evidence that the hip is dislocated.
Barlow test: The hip is adducted while it is flexed. By applying a force along the axis of the femur, the femoral head is forced out of the acetabulum. Partial or complete disruption of the relationship between the femoral head and acetabulum indicates that the test is positive. A positive Barlow test is evidence that the hip is unstable.
Clinical findings in the toddler:
Limp
Length difference
Trandelenburg sign: Leaning of the trunk towards the pathological side while standing on the pathological side, due to weakness in the gluteus medius
Radiological Examination:
Since the capital femoral epiphysis is not ossified, the ideal imaging method in the first 6 months is hip USG. With Hip USG, the femoral head and acetabulum cartilage and the relationship between them are evaluated. Pathology in the hip is classified by obtaining angular values representing cartilage acetabulum and bone acetabulum. USG is a guide in both diagnosis and treatment. In places where USG is not possible, the relationship between the direct pelvis radiograph and the femoral head acetabulum is evaluated.
There are reference lines in the direct radiography. The transverse line connecting the growth cartilages in both acetabulums is called the Hilgenreiner line, and the line descending perpendicular to this line from the lateral corner of the acetabulum is called the Perkins line. These two lines divide the acetabulum into 4 quadrants. In normal hips, the capital femoral epiphyseal nucleus should be in the lower inner quadrant. Being in the lower outer quadrant or upper outer quadrant indicates that the hip is subluxed or dislocated. In young babies where the capital femoral epiphyseal nucleus is not visible, the medial corner of the proximal metaphysis of the femur is evaluated.
Shenton. Line: The upper edge of the obturator foramen is continuous with the medial femoral neck with a virtual line in normal hips. In pathological hips, there is continuity between the medial femoral neck and the upper edge of the obturator foramen. It is not shown.
Acetabular angle-index: It is the angle between the line connecting the lateral corner of the acetabulum to the acetabular growth cartilage and the Hilgenreiner line. It shows the development in the acetabulum. A temperature above 30 degrees in newborns and above 24 degrees in 24-month-old babies indicates developmental delay-dysplasia in the acetabulum.
Computed tomography and magnetic resonance imaging have no place in the diagnosis of DDH.
Treatment of DDH:
The earlier DDH is detected, the easier and more effective the treatment will be.
The aim of the treatment is to obtain a concentric reduced stable hip.
The treatment is completed. Steps:
Hip reduction
Preservation of reduction
Monitoring and treatment of acetabular growth retardation
DDH treatment varies depending on the age of the patient.
Treatment tools:
Conservative treatment - Abduction device - Pavlik Bandage
Closed reduction and pelvipedal cast (KR-PPA)
Adductor tenotomy
Open reduction and PPA (AR-PPA)
Open reduction iliac osteotomy-PPA
Open reduction, femoral shortening, derotation, iliac osteotomy PPA
In newborns, the hip and knee joints are in a flexed position. This position is necessary for the normal development of the hip. Any intervention that will disrupt this position and force the hip and knee into extension will harm the physiological development of the hip. The first aim of the treatment is not to harm the physiological development of the hip. Swaddling is the most important factor that disrupts the normal development of the hip.
Abduction device is the name given to applications that keep the baby's hips in abduction between 40-60 degrees. Pavlik The bandage is a device with chest and leg bands that allow the hip to remain in a minimum of 90 degrees of flexion and 40 degrees of abduction. If, as a result of USG, developmental delay is detected in the baby's hip within the first 3 months, the hip development is followed with an abduction device until it returns to normal. If the developmental delay does not return to normal, the next treatment step, the Pavlik bandage, is used. During USG follow-up, the Pavlik bandage should be applied at 3-4 weekly checks until the hip returns to normal. It is followed by . If there is no progress in the development of the hip during follow-up, the next step, KR-PPA, should be applied. KR-PPA is the first treatment option since the Pavlik bandage will be difficult to apply in babies with pathology older than 6 months.
KR-PPA
KR-PPA
strong>: It is the reduction of the hip under general anesthesia with radiological control, if any, and the application of a pelvipedal cast in the reduced position. PPA is a body cast that starts at the chest level and ends at the ankle on the pathological side and the knee on the other side, keeping the hip in a reduced position. After CR, babies usually stay in PPA for 3 months.Adductor tenotomy: Shortness of the adductor muscles in the hips restricts movements, makes reduction difficult and causes re-dislocation. If necessary before reduction, the adductor longus tendon is cut in the groin area and tonotomy is applied.
KR-PPA: In babies around 1 year old, soft tissues fill the inside of the acetabulum, and the capsule and ligaments around the hip replace the femoral head. It may have developed in a way that prevents it from entering. In these babies for whom closed reduction is not possible, the hip joint is surgically opened, the structures that prevent the femoral head from entering are removed and the femoral head is placed in place. After this procedure, PPA is usually applied for 6 weeks.
Iliac osteotomy: Due to the developmental delay in the acetabulum in babies older than 18 months, an adequate roof has not been formed to cover the femoral head. Osteotomy performed on the iliac bone aims to ensure adequate roof formation by tilting the acetabulum to cover the femoral head.
Femur shortening, derotation: In untreated older children, the muscles, capsule and ligaments around the hip become tense as a result of the superior displacement of the femoral head. It becomes difficult to replace the femoral head. In these patients, in addition to AR and iliac osteotomy, shortening is applied to the femur from the subtrochanteric region to facilitate reduction and internal fixation is performed. PPA is usually applied for 6 weeks.
Treatment complications:
Inadequate development of the hip
Redislocation of the hip
Femoral head avascular necrosis
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