The timing of Pavlik harness removal in patients with developmental dysplasia of the hip is typically determined by clinical examination. Ultrasound is considered more sensitive than clinical examination in diagnosis of instability of the hip, but it is not routinely used in cases of developmental dysplasia of the hip, especially when determining the timing of Pavlik harness removal. The purpose of this study is to investigate if ultrasound examination is more effective than clinical examination alone in determining completion of Pavlik harness treatment. Fifty consecutive infants with developmental dysplasia of the hip were given both a clinical examination and dynamic ultrasound examination to determine if Pavlik harness treatment could be discontinued. A pediatric orthopedist conducted the physical examinations. Both a radiologist and a pediatric orthopedist interpreted the ultrasounds. Cost estimates for ultrasound and operative procedures were obtained at our institution and compared. The average age at the time of Pavlik harness placement was 5.3 days, and the average age at the time of ultrasound was 54.3 days. There were 35 females and 15 males and 31 left hips, 4 right hips, and 15 bilateral hips. All 50 patient hips were deemed clinically stable prior to obtaining an ultrasound. The ultrasound interpretations by a radiologist and pediatric orthopedist were in agreement in all cases. In one case, the ultrasound results did not correlate with results of the clinical examination. In that one case, the hip was clinically stable, but dynamic ultrasound revealed that the hip was located, but dislocatable. The Pavlik harness was reapplied to the patient for an additional 42 days. At 1-year follow-up the hip is stable and developing normally as determined by radiographs. The cost comparison revealed that the cost of 50 ultrasounds is less than the cost of a single operative procedure. The use of ultrasound to determine the timing of Pavlik harness cessation is justified from both a financial and a patient outcome perspective in this small study. Larger studies are needed before ultrasound examination used to help determine Pavlik cessation is considered standard of care.
The Pavlik harness is widely used as treatment for developmental dysplasia of the hip.1 It has a high success rate of reduction with relatively few complications.2 It was developed by Arnold Pavlik in 1946 and was first introduced at the meeting of Czechoslovak Orthopaedic Society in Prague as a new method of functional treatment. Pavlik developed the harness out of concern for avascular necrosis of the femoral head with previous unsuccessful treatment.3
Various screening strategies are used for detection of developmental dysplasia of the hip, including clinical examination, history and physical examination, and ultrasound examination. Physical examination has been found to be less sensitive than ultrasound examination in detecting instability of the hip.4 Ultrasound interpretations are operator dependent, and in some cases may be too sensitive in detecting clinically relevant cases of dysplasia. Physical examination in the neonatal period requires patience and skill. The physical signs change as the infant ages and none are pathognomonic.5 However, the use of ultrasound in the diagnosis and management of children with developmental dysplasia of the hip remains controversial.6-16
The use of ultrasound in orthopedic practice was pioneered by Graf in Austria in the 1970s17,18 and by Harcke et al19,20 in the United States. Because of its unique ability to assess the hip simultaneously from morphologic and dynamic points of view, Harckes method is more dynamic and resembles clinical examination under sonographic control. Grafs method is more static, describing the exact anatomic structure of the hip joint.21
Ultrasound is used as a routine screening test in several European countries and elsewhere.22 In the United States, ultrasound is not used as a screening test for all newborns because of cost issues. Graf23 suggests that ultrasound screening is cost effective given the high cost of subsequent developmental dysplasia of the hip treatments. The American Academy of Pediatrics recommends clinical screening of all newborns by physical examination and referral to an orthopedist when positive findings are present.24,25
If ultrasound is more sensitive than clinic examination in the diagnosis of developmental dysplasia of the hip,4 is it also more sensitive at determining Pavlik success? What role does ultrasound have in determining cessation of Pavlik treatment? Many orthopedists already use ultrasound to monitor Pavlik treatment and for cessation decisions. From an outcomes perspective, is ultrasound cost effective in determining the cessation of Pavlik treatment?
The purpose of this study was to determine if the use of ultrasound at the time of harness discontinuation would be beneficial. We sought to determine if ultrasound would identify any cases of hip laxity that were not evident on clinical examination, thus altering the treatment.
Materials and Methods
We prospectively studied 50 consecutive infants over a 14-month period who were placed into a Pavlik harness at our institution. The study was approved by our Institutional Review Board. The parents of participants were informed of the study and volunteered for participation. Prior to this study we did not use ultrasound to make decisions about Pavlik harness cessation.
The following protocol for developmental dysplasia of the hip is used at our institution: Pediatricians screen all newborns and consult the Division of Pediatric Orthopedics for any questionable hips. All such consults are seen by pediatric orthopedic faculty and are reexamined. Any clinically dysplastic hips, as determined by Barlow and Ortolani testing, are placed into a Pavlik harness; patients are asked to follow up in approximately 1 week in clinic. Ultrasound is not routinely used at the time of initial nursery exam at our institution. Harnesses are worn at all times and the infants are examined every 2 weeks in clinic. Hips that are determined to be clinically stable at 7-week clinic follow-up have the harness discontinued and are followed up at approximately 6 weeks (at 3 months of age) for an AP radiograph of the pelvis. Hips that are developing appropriately based on exam and radiographs at 3 months of age are followed in 3-month intervals until 1 year of age. They are then discharged from clinic if radiographic parameters are determined to be within normal limits.
Most patients were seen and placed into a harness in the newborn nursery, while a few were seen in clinic, with the oldest being 42 days of age at the time of Pavlik harness placement.
Patients in this study were followed in clinic for at least 6 weeks. After at least 6 weeks of harness wear, the patients were examined by only 1 of the 2 attending physicians who were both specialty trained in pediatric orthopedics (K.D.C., D.Y.). Patients whose hips were considered clinically stable by Barlow and Ortolani testing were then sent for an ultrasound. The ultrasound was performed by 1 of 2 attending radiologists who were both specialty trained in pediatric radiology (J.A.H., L.S.). The pediatric orthopedic attending who did not do the clinical examination read the ultrasound along with the radiologist. In hips that were considered clinically stable and had a normal ultrasound, the harness was discontinued and they were followed up at approximately 3 months of age. Any patient whose hips were clinically unstable at 6 weeks continued in the harness and did not have an ultrasound. Any patient deemed clinically stable, but whose ultrasound showed laxity, was to be placed back in the harness and reassessed every 2 weeks.
Patient billing records were used to determine cost comparisons. In addition to the cost of ultrasound, we determined the cost of the operating room procedure to treat residual dysplasia. We documented the cost of an arthrogram, closed reduction, and spica casting, as well as the cost for open reduction and spica casting.
Of 50 patients, 15 were boys and 35 were girls. The harness was placed, on average, on day of life 5.3 (range, 1-42), with 40 of the 50 patients having had a harness placed in the hospital on day of life 1 or 2. The ultrasound was obtained on day of life 54.3 (range, 40-99). The harness was worn, on average, 50 days (range, 40-66) prior to the ultrasound examination. We attempted to follow patients for at least 1 year, but 8 patients were lost to follow-up before 1 year of age. The average follow-up was 11.7 months (range, 2 to 20). Six patients were followed for <9 months, and 44 of the 50 patients were followed until at least 9 months of age. Bilateral hip laxity was noted in 15, right hip in 4, and left hip in 31 cases. The Table summarizes patient demographics and results.
Other significant medical problems were noted in 4 of the 50 patients (8%). Four infants were pre-term; the others were term. Two infants had a hyperextension deformity of the knee treated concurrently in the Pavlik harness along with the hip.
As per protocol, all hips were determined to be clinically stable at the time of the ultrasound examination. All ultrasound exams were interpreted the same by both the radiologist and the orthopedic surgeon, ie, the orthopedist and the radiologist agreed on all ultrasound interpretations. There were 49 patients determined to have stable exams and normal ultrasound exams.
One patient, deemed clinically stable, had an ultrasound exam that showed the hip was located but still dislocatable as interpreted from ultrasound by both radiologist and orthopedist (Figure). This patient had the harness replaced and wore it an additional 42 days while being examined every 2 weeks for harness adjustments. The ultrasound was repeated at that point, and the hips were deemed stable. Plain radiographs were also deemed normal, and the harness was discontinued. This patient was followed until 1 year of age. Her exam and radiographs at that time were normal; her ossific nucleus was well formed and her acetabular index was <20° on both hips.
The Medicaid reimbursement for an ultrasound is $106.88. The total cost for 50 tests would be $5, 344.00. The cost for an arthrogram, closed reduction, and spica casting is $7,132.65. Open reduction and spica casting is $18,200.91 with no osteotomies. Femoral and pelvic osteotomies increase the cost to over $38,000.00.
Ultrasound can be used in infants with developmental dysplasia of the hip at various stages in their diagnosis and treatment.6-16 A traditional approach is to use no ultrasound and to rely on clinical exam and radiographs only in the diagnosis and follow-up treatment of developmental dysplasia of the hip. The most ultrasound-intensive approach would be to use ultrasound for the initial screening of all newborns, at several points during Pavlik harness treatment, and then for several months after the harness is discontinued. It is established that the ultrasound examination can provide useful information,1 so the issue becomes how many ultrasound examinations are necessary and at what point additional ultrasound examinations become redundant.
The approach used at our institution is to rely on the traditional Ortolani and Barlow examinations for the diagnosis of developmental dysplasia of the hip in the infant and prior to placing the Pavlik harness. We now use ultrasound when we feel the infant is ready to have the harness discontinued, as a final quality check of the harness treatment. Our results show that of 50 cases, the ultrasound examination did not correlate with the clinical exam in 1 case. In that case, the hip felt reduced and stable on clinical exam at the time of harness discontinuation but was determined to be reduced and unstable on the basis of the ultrasound examination. We were alerted to extend the time in the harness to ensure that reduction would be maintained for the long term. At 1-year follow-up this patient had normal hip development on AP radiograph and required no further interventions.
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|Figure: Resting coronal ultrasound showing the 1 dislocating hip (A). Note the anterior and posterior limbs of the acetabulum (arrows). The speckled cartilanginous femoral head (H) is situated normally in the acetabulum. With the Barlow maneuver, the femoral head is no longer visible (B). The anterior and posterior limbs of the acetabulum are still visible (arrows), but now the femoral neck (N) is in view. The femoral head has dislocated posteriorly. With the transducer at a lower level, still in the coronal plane, the femoral head (H) is clearly visible, but there is no evidence of the acetabulum (C). |
Our experience with the treatment philosophy of getting the first ultrasound only at the time of Pavlik discontinuation has been satisfactory. We have achieved good results with Pavlik harness treatment as determined by the ultrasound evaluations, yet have kept the number of ultrasound examinations per patient to a number much less than that of other studies.20
Is the use of ultrasound cost effective in determining Pavlik harness success? At our institution, the Medicaid reimbursement for an ultrasound is $106.88, making the total coast for 50 tests $5,344.00. If an unstable hip was missed and went on to need further treatment, that hip might require an arthrogram, closed reduction, and spica casting. Alternatively, it might require open reduction and spica casting. The cost for arthrogram, closed reduction, and spica casting is $7,132.65. Open reduction and spica casting cost $18,200.91 with no osteotomies. Femoral and pelvic osteotomies can increase the cost to over $38,000. Clinic follow-ups with radiographs and braces would make the cost of closed or open reductions much higher. Depending on the brace used and number of clinic follow-ups, the additional costs could be several thousand dollars. So, if 1 of 50 hips were diagnosed by ultrasound to be unstable at 6 or 7 weeks of life, thereby avoiding surgery, ultrasound would be cost effective.
A limitation of the cost analysis is that the data we supply represents charges and may not represent a true cost. Our intent was to provide a relative value for each procedure and that of imaging studies so that an estimation of cost comparison could be made. The numbers provided cannot be generalized to all communities and practices. Another limitation of this study is the small number of patients and relatively short-term follow-up. We routinely follow our patients for the first year of life and discharge them from clinic if the hips radiographically appear normal; we recognize other authors might prefer longer follow-up. In order to validate our results, a large, multi-center study would be required.
We do not suggest that every infant whose dysplasia was not recognized in the 6- or 7-weeks of age range would ultimately be subjected to invasive procedures. An infant who was noted to have dysplasia by radiographs could likely be treated with repeat Pavlik harnessing or abduction bracing in many cases if the dysplasia was discovered in the 3- to 6-months of age range. We have, however, noted that some parents do not bring their children back for follow-up once the Pavlik harness is discontinued. In this series we followed the patients closely and made several phone calls whenever clinic appointments were missed, and we still lost 8 of 50 patients (16%) to follow-up. It is conceivable that a patient with clinically unrecognized residual dysplasia at the time of Pavlik cessation would be lost to follow-up, and it is for that reason that the economic values for the invasive developmental dysplasia of the hip procedures are used for comparison.
Each physician would have to decide how many missed diagnoses it would take to make ultrasound clinically meaningful. This cannot be looked at from a purely financial standpoint, and early detection with nonoperative Pavlik care is preferable to operative interventions in the treatment of developmental dysplasia of the hip from both a financial and patient outcome perspective.
Ultrasound identified 1 patient of 50 with persistent hip instability at the expected conclusion of Pavlik harness treatment. We believe that clinical examination and ultrasound should be used to determine the timing of cessation of Pavlik harness treatment for developmental dysplasia of the hip. Because of this study, we now use ultrasound to help decide the timing of cessation of Pavlik harness treatment. A larger, multi-center study would be required to validate the use of ultrasound before it could be considered a standard of care in determining Pavlik harness cessation.
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Drs Carmichael, Longo, and Yngve are from the Department of Orthopedic Surgery and Rehabilitation, and Drs Hernandez and Swischuk are from the Department of Radiology, The University of Texas Medical Branch, Galveston, Texas.
Drs Carmichael, Longo, Yngve, Hernandez, and Swischuk have no relevant financial relationships to disclose.
Correspondence should be addressed to: Kelly D. Carmichael, MD, Division of Pediatric Orthopedics and Scoliosis Surgery, Department of Orthopedic Surgery and Rehabilitation, 301 University Blvd, Galveston, TX 77555-0165.