AAOS Clinical Practice Guideline

Developmental dysplasia of the hip is seen in many orthopaedic practices. The American Academy of Orthopaedic Surgeons (AAOS) Clinical Practice Guideline (CPG), Detection and Management of Pediatric Developmental Dysplasia of the Hip in Infants up to Six Months of Age, is a summary of the available literature designed to help guide the surgeon and other qualified physicians in the management of this condition. This case presentation highlights how these guidelines can be helpful to the clinician when deciding the course of treatment. History and Physical Examination A girl 4 days of age presents to the pediatrician with a left hip that, by physical examination, feels to be potentially Barlow maneuver positive (ie, dislocatable, but spontaneously reduces). The child has a history of frank breech position and a maternal aunt who had a “hip problem” as a child and received treatment. There is no distinct family history of early arthritis or known early surgery upon the hips. Consistent with the recommendation Imaging of the Unstable Hip of the AAOS CPG Detection and Management of Pediatric Developmental Dysplasia of the Hip in Infants up to Six Months of Age,1 (DDH CPG), the patient was not screened by ultrasound before clinical examination of the hips by the pediatrician. Upon the findings of the examination, the practitioner may follow the recommendations Evaluation of Infants with Risk Factors for DDH and Imaging of the Unstable Hip of the guideline. Moderate evidence supports performing an imaging study before 6 months of age in infants with one or more of the risk factors: breech presentation, family history, or history of clinical instability. Additionally, limited evidence also supports performing an ultrasound in infants <6 weeks of age with a positive instability examination to guide the decision to initiate brace treatment. This patient presented with all three risk factors, including positive clinical instability; therefore, an ultrasound study to guide treatment decisions would be the best course of action. Instead of performing an imaging study, the pediatrician decides not to initiate treatment and refers the patient to an orthopaedic surgeon. Management The orthopaedic surgeon sees the child at 14 days of age and finds that she is not Barlow maneuver positive, but she does have a feeling of increased motion of the left hip. The surgeon can now choose to wait 4 to 6 weeks to perform an ultrasound before initiating treatment. Under the DDH CPG recommendation Treatment of Clinical Instability, limited evidence supports the supposition that delaying treatment up to 9 weeks of age will not be detrimental to a patient with a positive instability examination. As an example of a case in which delayed bracing treatment still allowed for successful treatment, Figure 1 shows a radiograph of an infant who presented with a dislocated, irreducible hip at 13 weeks of age. The practitioner chose to make a radiograph; however, at this age, the practitioner could have obtained an ultrasound study. The radiograph shows a dislocated femoral head. Bracing treatment was initiated with a Pavlik harness. A radiograph (Figure 2, A) and ultrasound image (Figure 2, B) obtained 1 week into bracing treatment showed the hip had been reduced.Figure 1: PA radiograph of a 13-week-old infant presenting with a dislocated, irreducible left hip.Figure 2: A, AP radiograph of the patient in Figure 1 demonstrating the reduced hip following 1 week of Pavlik harness treatment. B, Ultrasound study taken at the time of the radiograph demonstrating the reduced hip with an α angle of 55° and a β angle of 33°.Considering this example, if an ultrasound performed on the case study patient at 8 weeks of age were to find a hip instability, treatment could be initiated at that point with no effect on the treatment outcome. If brace treatment were to be initiated, the DDH CPG recommendation Type of Brace for the Unstable Hip provides guidance for choosing the type of brace. Limited evidence supports use of the von Rosen splint over the Pavlik, Craig, or Frejka splints during initial hip instability treatment. The recommendation Monitoring of Patients During Brace Treatment would then provide further guidance on the monitoring of patients during brace treatment. Limited evidence supports the performance of serial physical examinations and periodic imaging assessments throughout treatment duration. The orthopaedic surgeon decides to delay initiating brace treatment and instead reexamines the child at 24 days of age and finds a stable hip. An ordered ultrasound shows an α angle of 45° on the left contrasted to an angle of 60° on the right. At this point, the practitioner may follow the guideline recommendation Stable Hip with Ultrasound Imaging Abnormalities. Limited evidence supports observation without a brace for infants, such as the patient who presents with a clinically stable hip with morphologic ultrasound abnormalities. The surgeon decides to continue surveillance without initiating brace treatment. An ultrasound repeated 4 weeks later shows that the α angle is now 50° with a stable hip. After continued surveillance under the DDH CPG recommendation Stable Hip with Ultrasound Imaging Abnormalities, the α angle of the left hip improves, although it has still not reached the normal value. Continuing observation as the patient gets older, the practitioner may then follow the recommendation Imaging of the Infant Hip when the patient reaches 4 months of age. Limited evidence supports the use of an AP pelvis radiograph instead of an ultrasound to assess DDH in infants beginning at an age of 4 months. This allows for determination of the acetabular index to help guide treatment decisions. Outcome The surgeon sees the child again at 4 months of age. At this time, a radiograph is obtained that shows an acetabular index of 30° on the left and 28° on the right, with no break in the Shenton line. The patient appears now to have a clinically stable and normal hip by imaging study. Under the DDH CPG recommendation Surveillance after Normal Infant Hip Exam, the practitioner may continue surveillance after a normal hip examination because limited evidence supports re-examination of previously screened infants on subsequent visits before 6 months of age.