Hip I: Developmental Dysplasia of the Hip
John M. (Jack) Flynn, MD
Wudbhav N. Sankar, MD1
1Guru:
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Diagnosis
Perhaps most important aspect of staying out of trouble with developmental dysplasia of the hip (DDH) is making the diagnosis early. Delay in diagnosis may lead to a worse outcome, more invasive treatment, and legal action. For instance, it’s well recognized that treating a dislocated hip beginning after 7 weeks of age has a worse outcome than treatment earlier. For the pediatric orthopaedist, the vast majority of cases are referred when an abnormality has been detected by the pediatrician or neonatologist either on the physical examination or in the patient’s family history. It is incumbent upon the pediatric orthopaedist to either prove that the newborn or child has a completely normal hip, or carefully characterize the extent of pathology and the treatment or surveillance that is appropriate.
THE GURU SAYS…Getting baseline ultrasounds in my practice for patients with known DDH has shown me that I have often missed subluxations and dislocations on the contralateral side. Keep in mind that an irreducible hip dislocation will have a negative Barlow and Ortolani test! While it may not be consistent with AAP recommendations or cost-effective, I think the only way to stay out of trouble with the diagnosis of DDH is to get an ultrasound in any baby in whom DDH is at all a concern. Pediatric orthopaedists simply cannot miss this diagnosis.
WUDBHAV N. SANKAR
DDH is the most common hip disorder in children with the typical rate of 1% to 3% for all newborn babies. Included in this large number is a wide spectrum of pathology, from hip laxity and acetabular dysplasia to frank fixed hip dislocation.
Taking a few moments to obtain an infant’s history, including the associated risk factors for DDH such as breech delivery, family history of DDH and torticollis, is essential. While the presence of risk factors should heighten a clinician’s suspicion of DDH, remember that the majority of cases of DDH have no risk factors present, and the majority of infants with risk factors do not have DDH.
THE GURU SAYS…The Barlow and Ortolani maneuvers should be performed very gently in order to prevent the infant from guarding and allow you to pick up what can be a subtle finding. I tell residents that if the blood leaves your capillary beds of your fingers, then you are squeezing the child’s thighs too hard!
WUDBHAV N. SANKAR
▶ Pearls and Pitfalls of Physical Examination
▶ In the newborn with bilateral dislocated hips, the Galeazzi test is normal and abduction equal and possibly normal. With bilateral dislocated hips in a newborn, absence of normal hip flexion contractures may be the only finding that suggests DDH on physical examination. In an older child, lordosis and a waddling gait suggest bilateral DDH.
▶ Examine the baby on a table when performing the Galeazzi and abduction test for maximum accuracy. A screaming baby is easier to examine on the mother’s lap, but the examination will not be as accurate.
▶ Gently perform the Ortolani and Barlow tests multiple times—it can take a few iterations to sense the sliding of the cartilaginous femoral head in and around the acetabulum.
▶ The Ortolani and Barlow tests will not pick up fixed dislocations, as may occur in older children, nor will they unveil teratologic dislocations. For this reason, be sure to look for asymmetric abduction and a positive Galeazzi test in all cases.
RADIOLOGY
The role of ultrasound screening is quite complex and controversial from a public health standpoint. In some European countries, ultrasound screening of all newborns is routine. In the United States and many other countries, ultrasound evaluation is reserved primarily for babies at risk (history of breech position or DDH in the baby’s family).
The femoral head begins to ossify in most children between 4 to 7 months of age. Prior to 6 months of age, ultrasound is ideal for DDH evaluation because it provides both morphometric information as well as a test of hip stability. The femoral head position, acetabular depth, and capsular laxity can be objectively assessed in one simple study with no radiation to the baby. An AP pelvis radiograph is used after 6 months of age, when ossification of the femoral head makes ultrasound more difficult, and stability information is less of a factor. Plain radiographs of infants can be misleading if one confuses an absence of a frank dislocation to be a sign of a normal hip.
THE GURU SAYS…The appearance of an ossific nucleus is often delayed in hips with DDH. In these cases, judge the position of the medial and midportion of the proximal femoral metaphysis to determine if the hip is located.
WUDBHAV N. SANKAR
It is important to understand the significance of femoral rotation on a hip radiograph. Shenton line breaks with external rotation and may suggest DDH. Another pitfall of external rotation of the hip on a hip radiograph is that it creates the illusion of hip valgus.
A Scale for Communicating DDH Severity to Parents
Hip click felt or skin fold asymmetry seen, but imaging looks normal—This is a normal hip
Hip click felt or skin fold asymmetry seen, but imaging shows slight immaturity
Usually a breech baby, normal examination—Ultrasound shows mild laxity and dysplasia
Usually a breech baby, normal examination—Ultrasound shows moderate laxity and dysplasia
Positive Barlow
Positive Ortolani and Barlow
Infant with incompletely/irreducible hip
Walking DDH, hip partially reducible, associated dysplasia
Walking DDH, irreducible, severe dysplasia
Older school-age child with completely missed DDH/dislocation
Treatment
For all involved—parents, grandparents, the referring pediatrician, and the pediatric orthopaedist—it is helpful to talk about DDH as a spectrum, and a 1 to 10 scale adds value to the conversation. A “1” would be a hip click felt or skin fold asymmetry seen, but imaging looks normal—this is a normal hip. A “10” would be the older school-age child with completely missed DDH/dislocation. In general, we successfully treat lots of “2 and 3” with observation, lots of “3 to 6” with Pavlik harness and Ilfeld braces, and “7 to 9” with surgery. But everyone involved should know that the journey is much longer the higher the number, and risks increase based on what presents to the pediatric orthopaedist’s office on day 1. Early detection is obviously optimal, but even children who are privileged to be born in a nation with an outstanding health care system can walk in at age 3 with both hips dislocated and a presenting complaint of “toe walking” (Fig. 24-1). NEWSFLASH! Babies who were in the breech position have about four times greater chance of rapid resolution of newborn hip dysplasia than babies who have a family history, or no apparent predisposition to DDH.
PAVLIK HARNESS
The Pavlik harness is the first-line treatment for babies up to 6 months of age. The sooner the Pavlik is started, the better the results. Although many parents will have Googled “Pavlik” before arrival, expect tears from many as they
anticipate their newborn strapped into the device. A few lines of discussion really help ease the emotional strain that the new parents are feeling. First, be sure the families understand that a dislocated hip (and the process of relocating the hip) is completely painless for the babies. It’s logical to think their infant is in pain; disabuse them of this notion. Secondly, put things in perspective for them. The Pavlik harness can be 95% successful if started early and used properly. It has saved countless hips over the past three generations. The alternative is weeks or months in a body cast, or perhaps surgery. Painting this picture of high success and avoidance of surgery before they lay eyes on the velcro and cloth straps of the Pavlik makes the whole initial fitting less stressful, and treatment compliance much more likely.
anticipate their newborn strapped into the device. A few lines of discussion really help ease the emotional strain that the new parents are feeling. First, be sure the families understand that a dislocated hip (and the process of relocating the hip) is completely painless for the babies. It’s logical to think their infant is in pain; disabuse them of this notion. Secondly, put things in perspective for them. The Pavlik harness can be 95% successful if started early and used properly. It has saved countless hips over the past three generations. The alternative is weeks or months in a body cast, or perhaps surgery. Painting this picture of high success and avoidance of surgery before they lay eyes on the velcro and cloth straps of the Pavlik makes the whole initial fitting less stressful, and treatment compliance much more likely.
 Figure 24-1 Newborn from rural area with no pediatric orthopaedist in area. A: “Hip click” was evaluated and the examination seemed normal, but as a precaution they sent the infant for an AP pelvis radiograph, which was read by the local radiologist as “normal.” B: Seen at a children’s hospital at age 2 for another neglected problem. The pediatrician did a comprehensive evaluation, thought a follow-up hip image was wise, and sent the child for urgent orthopaedic evaluation when the new X-ray showed both hips were dislocated. LESSONS: (1) The examination may seem normal in an infant with bilateral fixed hip dislocations. (2) Use ultrasound not radiographs on infants. (3) If you see a toddler who has potentially unresolved concerns of hip dysplasia, get new X-rays. Cost is low and the findings may be very important. |
THE GURU SAYS…While the recommendation of a Pavlik may seem easy to an orthopaedist, this device can be extremely scary especially for new parents. It’s really helpful to train a nurse or other assistant to teach the families about clothing, car seats, tummy time, etc. This will save many phone calls to the office after the appointment.
WUDBHAV N. SANKAR
The anterior straps should flex the hip 90° to 100° and posterior straps should limit adduction to no more than neutral, which should maintain the hips in a reduced position and reduce likelihood of re-dislocation. The anterior and posterior straps should be taped into position to prevent an unwanted change in hip position by caretakers “adjusting” the straps. Be sure caregivers know that there should be “room for two fingers” under the chest strap at all times (Fig. 24-2).
 Figure 24-2 There should always be two-finger space under the chest strap. (Courtesy of Meg Morro, MD and Wudbhav N. Sankar, MD. Used with permission of CHOP Orthopedics, Philadelphia, PA.) |
Too much hip flexion can cause a femoral nerve palsy or inferior subluxation of the femoral head. Be sure to observe that the knees actively extend at each office visit (legs kicking) while in the harness to demonstrate a functioning femoral nerve. If femoral nerve palsy is noted, it is best to stop use of the harness for a short period of time, then switch to an alternative method such as an Ilfeld brace (Fig. 24-3). Brachial plexus injury has been reported with Pavlik harness use that promptly resolved when the harness was removed.
THE GURU SAYS…The development of femoral nerve palsy is usually associated with a high dislocation (rather than ultrasonographic dysplasia). Once femoral nerve palsy develops, the success of a Pavlik harness goes down dramatically. To maximize the success of nonoperative treatment, try restarting the harness with less flexion or switch to an abduction orthosis (like an Ilfeld brace), which holds the hips in less flexion as soon as the palsy resolves. A long delay in treatment greatly increases your chances of ultimately needing surgery.
WUDBHAV N. SANKAR
 Figure 24-3 The Ilfeld abduction brace is an excellent solution for many babies when the Pavlik fails. Many parents find it easier to use. The abduction and anterior push, without the flexion, is just the solution that many DDH hips need. (Used with permission of CHOP Orthopedics, Philadelphia, PA.) |
Avascular necrosis (AVN) has been reported with Pavlik harness treatment and may be related to the initial magnitude and position of hip displacement rather than the method of treatment. Extreme abduction in the harness may lead to AVN, though it is rare.
To stay out of trouble, abandon the Pavlik harness if it’s not working. A very successful protocol is to obtain a no stress ultrasound in the Pavlik harness about 2 weeks after initial harness placement to confirm reduction of the hips. If the ultrasound shows that the position of the hip is improving but it is not perfectly reduced after 2 weeks in the harness, adjust the straps (perhaps a bit more abduction), then repeat the ultrasound about 2 weeks later. If the hips are now well reduced, then initiate 6 weeks of treatment. NEWSFLASH! If the hips cannot be reduced with the use of a Pavlik harness, an Ilfeld brace can be successful for
many, avoiding closed reduction and casting for all Pavlik failures (Fig. 24-4). The best DDH treatment ladder: Pavlik harness, then Ilfeld brace for Pavlik failures, then Spica cast for Ilfeld brace failures.
many, avoiding closed reduction and casting for all Pavlik failures (Fig. 24-4). The best DDH treatment ladder: Pavlik harness, then Ilfeld brace for Pavlik failures, then Spica cast for Ilfeld brace failures.
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