EARLY DIAGNOSIS AND PREVENTION OF DDH

Abstract

There is a very long way from diagnosis to treatment of the developmental dysplasia of the hip. Everything is complex: clinical examination is subtle and requires a long training. Treatment is not as simple as could be thought. The risks include approximate examinations and of standard, ready-made ones. The discussion has not been settled as to whether all children with hip instability can be clinically detected at birth. The complexity of the problem arises from the fact that only 10% of children who have instability at birth develop long-term problems if they are left untreated. It is well known, affirmed by several different studies that at birth the incidence of hip instability in approximately 1–4% of patients, with figure being higher in girls. There is also a consensus that a large majority of these unstable hips will become stable during the first few days of life, even without treatment. What is not known, however, is how many of those hip that become stable will become completely normal as the child grows. These two fundamental issues are of the utmost importance. They emphasize the significance of early examination (first 48 hours) in order to detect instability and employ careful follow-up of any newborn in whom hip instability has been identified.

Some children are at particular risk of hip instability. Those infants are labeled as “high risk”. They include children born in families with hip instability, those presented by breech, first born children or products of oligohydramniotic pregnancies, particularly girls, those with the generalized joint laxity, those with torticollis and scoliosis, those with foot deformities and increased birth-weight over 4000g. Whilst all children should be screened at birth by a doctor experienced in clinical examination with particular attention directed to those children, who are considered high risk.

It must be emphasized that clinical examination is the most important for the detection of hip instability in newborns. Clinical examination should be very delicate, gentle, based on feelings rather than signs. Clinically, hip instability can be divided into: 1. irreducible dislocation, 2. reducible dislocation, 3. dislocatability, 4. subluxability. The clinical tests of instability were described by Ortolani and Barlow. Fully dislocated irreducible hip is a very rare condition and may be associated with neuromuscular abnormality. It represents dislocation well before delivery. In this form acetabulum is vacant, femoral head palpable posteriorly. There are no singns of Ortolani and Barlow tests. We can only find the sings of “pump”, which means there exists a movement along the long axis of the leg. This is the most severe pathology of the hip in DDH.The reducible dislocation is characterized by the Ortolani maneuver. With the hip flexed 90 degrees, we abduct the hip and than we feel and hear the click which is the sign of the reduction of the hip. Dislocatable and subluxatable are the most common types of pathology of the hip in DDH. This deformity arises at the end of pregnancy. This is characterized by positive Barlow test, which is the provoked-dislocation test. Using it we can dislocate or subluxate the hip. It is very rare to find restricted hip movements in newborns. The limited abduction of the affected hip is the sign typical for older children, more the 3 months of age. It is crucial to repeat the clinical examination even during the same office visit. Ultrasonography has changed our diagnostic ability for DDH. These direct examinations help us in hip evaluation in the first days of the newborn period. The exact Graf classification and methodology makes possible to classify all types of hip pathology irrespective of the examiner. Another important feature of ultrasonography is the ability to monitor the treatment not only in newborn period.

How to start with the prevention of DDH in newborn period? There is no any really good screening without collaboration of orthopedics surgeons and pediatricians. To achieve this, we must control our own environment, especially maternity hospitals and constantly keep pediatricians, pediatric nurses and obstetricians informed. There is no consensus in screening programs – general or limited. I personally recommend limited program. All newborns should be examined clinically after the delivery. The infants with positive or doubtful clinical signs and those with signs of high risk should be examined ultrasonographically immediately after delivery within first 2 weeks. The other children should be screened ultrasonographically at the time when most of the hips are mature enough. It is important, that if we live in the region with high percentage of late detected DDH (more than 3 months of age) the general clinical and ultasonographical screening program should be used.