Orthopedic and ultrasound assessment of hip stability of newborns referred by pediatricians with suspected Developmental Dysplasia

1 University of São Paulo, Ribeirão Preto Medical School, Department of Orthopedics and Anesthesiology, Ribeirão Preto, SP, Brasil. Cruz Orthopedic and ultrasound assessment of hip stability of newborns referred by pediatricians with suspected Developmental Dysplasia 2 Rev Col Bras Cir 46(6):e20192284 Another important historical step occurred when the possibility of cases of typical dysplasias with different severity profiles was recognized, as well as the evolutionary aspect of the condition and the possibility of not always being congenital, which led to the change of its name from “congenital hip dislocation” to “developmental dysplasia of the hip”6,7. Currently, the term "congenital dislocation" was reserved for late diagnosis or teratogenic cases, where the dislocation occurs intra-uterus and is usually accompanied by severe malformations of the various anatomical elements of the hip, with complete dislocation and irreducibility by conservative means. Another great benefit to the understanding of DDH came up with the use of ultrasound, which highlights the contribution Graf8-11, which made it possible to determine different degrees of the condition and select treatment. Currently, it is well established that pediatricians are important professionals in the diagnosis of DDH, as they are responsible for screening the newborn with suspected affection for referral to the orthopedist. In our institution, the partnership between pediatrician and orthopedist has been a long one in order to ascertain early diagnosis and treatment of DDH cases. Ortolani and Barlow tests12,13, as well as the presence of risk signs, constitute routine in newborn semiology. Thus, the objective of the present investigation is to evaluate the population of newborns in a public maternity hospital, referred to the pediatric orthopedics because of suspected DDH or the presence of risk factors. The hypothesis is that many suspicious cases occur, but without diagnostic confirmation with the objective exams. METHODS This is a cross-sectional, descriptive, retrospective study, with a qualitative and quantitative approach, of hips newborns (NB) referred from a public maternity hospital. When the pediatrician suspected or diagnosed a condition of the locomotor system, the newborn was sent to the pediatric orthopedics department of the same institution for complete orthopedic evaluation. In the presence of positive Ortolani or Barlow signs, the child was immediately referred. However, if there was no instability, but presence of risk signs for DDH, such as familial occurrence, pelvic presentation, nonspecific signs such as clicking, or there was doubt about hip stability, the child was referred at four weeks of age for examination of the hip expert. This delay was intentional to allow eventual cases of immaturity of the hip, which could simulate dysplasia, to have regressed upon orthopedic examination. Third-year orthopedic residents carried out the specialized Orthopedic examination, overseen by a pediatric orthopedist. In addition to general orthopedic evaluation, the hip was examined for pelvic asymmetry, presence of asymmetrical gluteal folds (Peter-Bade sign), shortening, Galeazzi sign, abduction limitation (Hart sign), and stability tests (Ortolani/Barlow). Positive family history of DDH, pelvic presentation and twin pregnancy were considered signs of risk. In hip instability, ultrasonography (US) was requested by the Graf method, quantifying the degree of dysplasia, and treatment was initiated. However, with normal physical examination but presence of risk factors, the ultrasound of the hips was requested around one month of life. Cruz Orthopedic and ultrasound assessment of hip stability of newborns referred by pediatricians with suspected Developmental Dysplasia 3 Rev Col Bras Cir 46(6):e20192284 Radiology residents specializing in the locomotor system performed the US exams under the supervision of an attending physician. We determined the alpha and beta angles, which delimit three zones once cast on the Graf ruler (Figure 1). In zone I there is only hip immaturity and there is no need for specific treatment, only follow-up. Zone II is subdivided into two areas: transition subzone, where patients may or may not be treated depending on their history and physical examination, and danger subzone, where cases are usually treated. Zone III hips are considered broadly dysplastic and require treatment9. We excluded cases of teratogenic dislocation (association with syndromes, multiple malformations or neuromuscular diseases). For the present evaluation, we collected data from medical records of newborns treated during the period between June 2015 and October 2017 (29 months). We followed the flowchart of figure 2. Figure 1. Graf ruler used to facilitate the interpretation of the degree of dysplasia and decide the approach. The alpha angle (α) values are in the upper limit and the beta (ß) angle values, in the lower limit (GRAF, 1984). Three regions are delimited. Figure 2. Flowchart used for selection and management in all cases. Cruz Orthopedic and ultrasound assessment of hip stability of newborns referred by pediatricians with suspected Developmental Dysplasia 4 Rev Col Bras Cir 46(6):e20192284 We entered the variables analyzed into an Excel® spreadsheet and analyzed the data descriptively by mean and standard deviation (SD). This study was approved by the Ethics Committee of the institution with Certificate of Presentation for Ethical Appreciation (CAAE) number 78086117.1.0000.5440.


INTRODUCTION
T he Developmental Dysplasia of the Hip (DDH) involves an evolutionary spectrum of childhood disorders that begins with instability and acetabular dysplasia, and may lead to sub-dislocation and even complete dislocation of the hip during growth.
It presents a typical form, in which the child is otherwise normal, and a teratogenic form, in which the hip is usually dislocated at birth due to syndromic systemic conditions or neuromuscular disorders such as myelomyngingocele, arthrogryposis and others 1 .
Typical dysplasia may regress spontaneously in mild cases, but without treatment may result in painful conditions associated with joint degeneration and gait disorders 1 . The incidence of typical DDH depends on the geographic region and the literature analyzed, ranging from 1/1000 to 20/1000 live births [2][3][4][5] .
Although there are no official statistics in our country, it displays a higher incidence in the Southern region.
In the past, the condition was known as congenital hip dislocation, because the diagnosis was made late. Consequently, treatment started when the hip was already dislocated had poor results and many sequelae. From the beginning of the XX Century, great contribution was made by Ortolani, disclosing the possibility of early diagnosis and treatment of the condition. By involving nonorthopedic doctors in the diagnosis, especially pediatricians, Ortolani greatly contributed to the prevention of sequelae, which were very common in the orthopedic environment.

Original Article
Orthopedic and ultrasound assessment of hip stability of newborns referred by pediatricians with suspected Developmental Dysplasia.

Rev Col Bras Cir 46(6):e20192284
Another important historical step occurred when the possibility of cases of typical dysplasias with different severity profiles was recognized, as well as the evolutionary aspect of the condition and the possibility of not always being congenital, which led to the change of its name from "congenital hip dislocation" to "developmental dysplasia of the hip" 6,7       Given that the hip is such a stable joint in the adult, it is intriguing that it presents this degree of instability in the young child. Moreover, if we consider that the hip has an embryological origin in a single mesenchymal mass, which progressively differentiates into individualizing the acetabulum from the femur, with the creation of a gap between the mesenchymal nuclei, that is, the femoral head is originally formed within the acetabulum 27 . This leads to search for some factor that could alter this relationship after the formation of the joint. It is believed that there are two important factors in cases of DDH: acetabulum dysplasia and capsular-ligament laxity 27 .
Currently, diagnosis and treatment are based on morphological changes in the acetabulum, but this change is probably secondary to inadequate dynamic positioning of the femoral head before birth due to excessive capsule compliance in some individuals.
In summary, our results show that there was an overdiagnosis of hip instability in the pediatrician evaluation and, consequently, referral to the orthopedist. Although this may cause overload to the health service, this attitude is adequate, as it allows the patient a second assessment in a more specialized environment and with more technological resources.