Which action by the nurse demonstrates the correct technique to perform Barlows maneuver?

Previous Systematic Reviews

The AAP recommendations were based on an extensive review of the literature, including Medline and EMBASE searches through June, 1996.2, 3 Articles were included in the review if they helped to estimate one or more probabilities in a decision model comparing five screening strategies: no screening, screening high-risk newborns by physical examination alone; screening all newborns by physical examination alone; screening all newborns with ultrasound; and screening all newborns by physical examination conducted by an orthopedic surgeon. A total of 118 articles (5 comparative trials and 113 observational studies) were included in the review. The authors noted that no evidence was available for 13 of the 30 probabilities they sought to estimate.

The AAP review methods differed from ours in several respects. First, they used a different system to assess the quality of individual studies. Specifically, they developed a 7-item, 21-point quality scale. One item graded the method of assignment to groups (that is, “random”=3 points, “comparative arm”=2 points, “single arm”=1 point, and “haphazard”=0). Other scale items rated the degree to which the study results were applicable to one or more parameters in the decision model. By contrast, the USPSTF rating system examines characteristics of the study related to the internal validity of the results. Second, the AAP model incorporated experts' opinions when there were gaps in the published evidence. Thus, the quality of evidence supporting the reports' findings is quite variable.

The AAP review used 106 observational studies (which they described as “case series”) to estimate the chance of a positive screening examination for different patient populations and with different screening modalities. For example, they used 48 observational studies published between 1956 and 1996 to estimate the probability of a positive physical examination when screening was conducted by pediatricians. After examining the articles included in the AAP review, we determined that 36 of the 48 studies of screening by clinical examination reported results of screening in a population relevant to our review. We concluded that the AAP report made valid estimates of the rates of positive clinical screening examinations through 1996.

The AAP review found limited evidence on the yield of universal ultrasound and the value of serial examinations for DDH. More over, the AAP report did not focus on the comparative yield of clinical examination and ultrasound when both are applied to the same population. Also, while it examined how well risk factors predict a positive screening test, it did not examine how well risk factors predict confirmed cases of DDH.

Literature examining the effectiveness of nonsurgical or surgical interventions was outside the scope of the AAP review; assumptions about the effectiveness of these interventions were based on expert opinion. Its review of rates of AVN, which focused on the relation between the risk of AVN and the age of referral, identified fair-to-good quality evidence.

The CTFPHC report1 on DDH sought to answer many of the questions identified in the present review. This report was not accompanied by a comprehensive technical report as was the AAP study. The CTFPHC report cites fair evidence supporting serial clinical screening examination, but upon further review the evidence cited is sparse (see KQ 1). Their review of the role of ultrasound in screening focused on the single available controlled trial,21 but also summarized findings from 32 additional studies, predominantly descriptive in nature. The CTFPHC review also examined the nonsurgical intervention literature, but their criteria for evaluating the intervention literature were not explicit; their review included studies with radiological (rather than functional) outcomes. They found insufficient evidence to assess the effectiveness of abduction therapy. Finally, they concluded that a period of supervised observation is warranted prior to initiating therapy in hips diagnosed with DDH at birth, given the high rate of spontaneous resolution. Appendix 7 compares the degree to which the literature in the CTFPHC report met our inclusion criteria.

Key Question 1. Does Screening for DDH Lead to Improved Outcomes (including reduced need for surgery and improved functional outcomes such as: gait, physical functioning, activity level, peer relations, family relations, school and occupational performance)?

There are no prospective studies—either randomized or observational—comparing a screened to a non-screened population with measurement of functional outcomes after an adequate period of follow-up. There are also no controlled trials that compare surgical or nonsurgical treatment for early DDH to observation only.

In theory, early application of noninvasive treatments (e.g., a harness) to obtain a concentric and stable reduction of the femoral head in the acetabulum may obviate the need for surgery later on. However, the evidence that screening leads to a reduced rate of surgery is weak and indirect. The 2000 CTFPHC report, citing several descriptive studies, concluded “With serial clinical examination, the operative rate for DDH has decreased by more than 50% to 0.2–0.7% per 1000.”1 It should be noted that this reduction was observed at an ecological level: descriptive studies in screened populations were compared, indirectly, to unscreened populations or to historical rates. The studies were not comparative and did not report functional outcomes. In addition, while some studies suggest that surgical rates have declined since the adoption of universal screening programs, they do not indicate why. The decline might be attributable to increased rates of screening, but other factors, such as wider use of a period of observation before recommending surgery, could also account for the declining use of these surgical procedures.

The measure used in many comparative studies was the proportion of infants and children with DDH who had surgical intervention. If screening identifies more cases than usual care, it could reduce this proportion even if the same number of cases required surgery as before. For this reason it is difficult to determine whether a decrease in the surgical rate over time reflects the efficacy of noninvasive intervention or the inclusion of additional cases in the denominator who are at little or no risk of requiring surgery.

The findings are also inconsistent: some studies observed a decrease in operative rates,22–25 while others saw no change26, 27 or an increase.28–30 Ascertainment of cases was often flawed, and the studies span several decades, making it difficult to assess whether the varied results represent artifacts of data quality, secular trends, or differences in local practice styles.31 These studies are also limited because they typically do not follow the screen-negative population with the same vigilance as the screen positive population, and experience significant loss to follow-up in the screen positive population that can bias the outcomes.

More recent studies also have conflicting results. In 1998, the MRC Working Party on Congenital Dislocation of the Hip reported operative rates in a randomly selected, population-based survey of 20% of all births in the U.K.31 After adjustment for differences in ascertainment that had been overlooked in previous reports, the incidence of a first operative procedure for congenital dislocation of the hip was similar before and after screening was introduced (pre-screening rate range 0.66 – 0.85 per 1000, post-screening rate 0.78 per 1000 live births, 95% CI 0.72–0.84). Even in the screening era, 70% of the cases reported by surgeons to the registry had not been detected by screening. In 1999, Australian investigators reported the operative rate in the post-screening era using an existing perinatal database with information about birth defects and an inpatient discharge database to identify infants with congenital dislocation of the hip.32 In contrast to the U.K. study above, they reported an operative rate of 0.46 per 1000 live births and found that 97.6% of congenital dislocation cases were diagnosed before 3 months of age. The causes behind conflicting findings such as in these two studies are unknown.

Key Question 2. Can Infants at High Risk for DDH be Identified, and Does This Group Warrant a Different Approach to Screening than Children at Average Risk?

Risk factors are considered an adjunct to, rather than a substitute for, universal screening by physical examination. For example, the AAP recommends using risk factors to identify newborns whose risk for DDH may exceed the comfort level of physicians, prompting additional screening using ultrasound. The rationale for this approach is that, in high-risk newborns, clinical examination alone will miss many cases of DDH that ultrasound can identify. The assumptions underlying this approach are (1) risk factors can identify a group of newborns at a high risk of DDH and (2) ultrasound is more sensitive than clinical examination for identifying infants at risk of complications from DDH.

In case control and observational studies, breech positioning at delivery, family history of DDH, and female gender have been most consistently shown to have an association with the diagnosis of DDH. Additional risk factors may include maternal primiparity, high birthweight, oligohydramnios, and congenital anomalies.

Lehmann and colleagues conducted a meta-analysis of studies published through 1996 to estimate the probability of having a positive screening test for the three leading risk factors.2 Breech females (84/1000) had a dramatically higher than average risk (8.6/1000 for all newborns) of being screen-positive, followed by family history positive females (24/1000), breech males (18/1000), females with no risk factors (14/1000), and males with no risk factors having the lowest risk (3/1000).

The DDH reference standard in their synthesis was a positive Barlow and Ortolani test at the newborn screening examination. While this is a commonly used and reasonable measure of the disorder, it may overestimate the number of infants requiring therapy. Primary care and population-based cohort studies33–43 that included one or more of the major risk factors are summarized in Table 2. Consistently, only a minority (10–27%) of all infants diagnosed with DDH in population-based studies have identified risk factors (with the exception of female gender)37, 39, 40, 42 and among those with risk factors, between 1% and 10% have DDH.37, 40, 42 This wide range illustrates the impact of the reference standard on the relative importance of risk factors. Those studies with a stricter standard for diagnosing “true” DDH, for instance limited to those cases that receive treatment, demonstrate substantially lower rates of DDH among those with risk factors. For example, a recent cohort study of 29,323 births at one hospital, the prevalence of treated DDH was 20/1000 in breech females (vs. 110/1000 based upon the clinical exam), 12/1000 in family history positive females, 4/1000 in breech males, 5/1000 and 0.3/1000 in females and males with no risk factors, respectively.35 The substantial differences (4 fold in the case of breech females) in prevalence between the AAP estimates and this study reflect different diagnostic standards, and impact the predictive value of risk factors for DDH. More conservative estimates based upon “true” DDH makes the value of routine ultrasound for patients with given risk factors less certain. From a primary care perspective, a prospective, practice-based cohort study of a risk scoring or other risk assessment tool would provide the strongest evidence about the yield of selective screening of high-risk infants.

Several potential biases should be considered in evaluating risk factor data. In studies where the examiner is aware of patients' risk factor status, the diagnosis of DDH may be overestimated due to more careful or thorough examinations or more aggressive follow-up and reexamination in infants with known risk factors. Moreover, in retrospective studies researchers apply criteria to improve the reliability of their record review; this approach, while necessary to conduct such a study, reduces the influence of an equivocal or inaccurate history. A predictor such as family history may be less reliable in a prospective, practice-based study than in case control studies which exclude patients (charts) that have equivocal or incomplete information about it. Finally, investigators' awareness of the subjects' final diagnoses could have influenced the way they handled risk factor information.

Key Question 3. Does Screening for DDH Lead to Early Identification of Children with DDH?

Clinical screening for DDH includes the provocative Barlow and Ortolani tests of hip stability, and assessment of range of motion of the hip in abduction. In addition to clinical examination, the approach to screening may include imaging of the hip, traditionally by radiography and more typically today by ultrasound. Ultrasound methods include both static and dynamic assessments of the hip, and its use varies widely across developed nations. All methods used to screen for DDH are variably subjective and operator-dependent.

Recent prospective population-based and primary care practice-based studies14, 16, 35, 44–47 offering a within-group comparison of clinical examination and ultrasound screening are summarized in Table 3. Randomized trials21, 48, 49 of different screening modalities are summarized in Tables 4 and 5.

Table 4

Randomized Controlled Trials of Screening.

Table 5

Randomized Controlled Trial Training Approaches.

KQ 3a. What is the accuracy of clinical examination and ultrasound?

To measure sensitivity directly in a prospective study, infants who had negative initial screening tests must be followed and examined at older ages to identify false negative initial test results. Measuring sensitivity is also difficult because results of the Barlow test can be classified into several levels, rather than just two (“positive” or “negative”). Conversely, measuring specificity and false positives is difficult because, in most studies, all infants who have a positive screening test are treated with a nonsurgical intervention; the great majority improve, and it is impossible to say how many of them “responded” and how many of them did not have DDH in the first place.

Assessing the impact of a screening program on the rate of late diagnosis of DDH provides an indirect measure of sensitivity. It is apparent that screening tests performed soon after birth identify some individuals at risk of developing DDH sooner than they would otherwise be identified: most children would otherwise not come to medical attention until the age of walking (approximately 1 year) in most cases. However, it is difficult to quantify the impact of screening tests on the incidence of late diagnosis with the available literature. Studies of the impact of screening programs on the frequency of late diagnosis have had mixed results.23–25, 28, 32, 50–62 Most of these studies report the experience of a screening program in a defined geographic or hospital service area over many years. The comparisons are ecological, and these studies have the same methodological problems as those that examined the effect of screening on rates of surgical treatment (discussed above, Key Question 1). Some studies in this group reported that, after a screening program was adopted, late diagnosis was very rare, while others report that screening had no effect on the rate of late diagnosis, and that unexplained fluctuations in late diagnosis rates were observed from year to year within the post-screening era (Figure 3 and Figure 4).21, 23–25, 27–29, 36, 40, 50, 55, 60

Figure

Figure 3. Variation in Late Detection Rate by Screening Method 1978-1996.

Figure

Figure 4. Variation in Late Detection Rate by Year of Study Publication 1978-1996.

The lack of a practical confirmatory “gold standard” diagnostic test for DDH makes it difficult to assess—or define—false positives. Various reference standards appear in the literature, including positive clinical examination, ultrasound confirmation, radiographic confirmation, arthrography, persistence of abnormal findings on serial exam or ultrasound over weeks to months, diagnosis by an orthopedist, and use of treatment. The most meaningful reference standard defines “true” DDH as “those neonatal hips, which, if left untreated, would develop any kind of dysplasia and, therefore, are to be included in the determination of DDH incidence.”4

To apply this standard, a cohort study must follow infants for a long enough period without applying any treatment, in order to determine whether or not the abnormal findings persist and lead to clinical problems. In one good-quality prospective cohort study that followed untreated infants for 2 to 6 weeks, approximately 9 of 10 infants with initially abnormal ultrasound examinations revert to normal.4 Similarly, by 2 – 4 weeks of age, over 60% of infants identified at birth by abnormal clinical examination (Barlow or Ortolani tests) have reverted to normal when judged by repeat clinical examination or by ultrasound examination.6, 11, 63 Longer prospective studies21, 35, 63–68 and a systematic review of observational studies of ultrasound screening69 demonstrate that in untreated hips, mild dysplasia without frank instability usually (consistently over 90%) resolves spontaneously between 6 weeks and 6 months.

Table 3 includes population-based (or primary care clinic based) cohorts screened by clinical examination as well as ultrasound screening, published since the 1996 endpoint of the AAP review.14, 16, 35, 44–47 Despite variation in the reference standards used in these studies, several important findings emerge. First, a high proportion of hips diagnosed with minor findings of dysplasia undergo spontaneous resolution. It is important to note that minor dysplasia is not identified by clinical exam, but only by ultrasound. Due to the identification of anatomic variations that are marginal and self-limited, the potential exists for over-treatment on the basis of ultrasound. On the other hand, in 4 of the 7 studies in Table 3, 38% – 87% of abnormal findings on clinical exam were not DDH, leading to a similar risk of unnecessary therapy on the basis of clinical examination.16, 44, 45, 47 Very few of these studies followed patients longitudinally, particularly those patients who did not screen positive by exam or ultrasound.

In the first 4–6 months of life, ultrasound has been deemed to be a more appropriate test than radiographs for anatomic hip abnormalities as well as instability of the hip, due to incomplete ossification of the femoral head in early infancy. Though no study addressed the comparative value of ultrasound to radiograph in the 4–6 month time-frame, there is strong endorsement of this approach in the literature, ranging from historical studies reporting on timing of ossification and analyzing the technical challenges of hip radiography in the young infant,70, 71 to contemporary systematic reviews.2, 3

However, ultrasound screening is not without its shortcomings. In addition to the high rate of identification of nonpathological hip findings summarized above, the most widely used ultrasound-grading system, Graf classification,72 has come under scrutiny. The Graf score is used in the vast majority of the screening literature to differentiate normal hips from immature hips from minor dysplasia from major dysplasia; and stable from unstable, subluxable, and dislocatable/dislocated. Many studies base treatment decisions on these classifications. A study examining the reliability of Graf classification found that, among normal hips, intra- and inter-observer reliability is quite high, with a 98% chance of having the same assessment on future readings. However, among ultrasounds read as abnormal by at least one person, intra-observer reliability was moderate (kappa = 0.41) but inter-observer reliability was fair (kappa = 0.28). In addition, knowledge of the patients' history and physical exam vs. blinded review of the ultrasound lowered the intra-observer kappa from 0.41 to 0.37.73

Another study found moderate agreement between observers on determining morphology by subjective reading (kappa = 0.5), but this decreased to 0.3 when objective measurements of anatomic relationships were conducted. Grading of stability was moderate (kappa 0.42) between observers, when dislocatable and dislocated hips were grouped together. This study estimated that the decision to treat would have been affected in 2.4% of cases due to discordance between reviewers.74 Considerable effort had been given to standardizing ultrasound assessment in this study, including a training session and 100 repetitions of conducting measurements before the start of the study. Still another study found ultrasound reliability to be similarly suspect, with kappas ranging from 0.52 –0.68 and 0.09 to 0.30 for intraobserver and interobserver agreement, respectively, across seven anatomic measures used in grading DDH.75 These findings raise concerns about the operator dependence of this evaluation for DDH, and may shed light on the variability of ultrasound screen positive rates found in the literature.

While there are no trials or comparative studies of a screened to an unscreened population, 2 randomized controlled trials48, 49 and 1 nonrandomized controlled trial21 provide some insight into the accuracy of clinical examination. These trials reported data about test performance of one screening strategy versus another (Table 5). The first randomized controlled trial (RCT) compared universal ultrasound screening to selective screening at a population level.49 In the trial, patients at the University of Trondheim, Norway were randomized over a 5 year period to one of two groups: clinical exam and ultrasound or clinical exam and selective ultrasound. In the first group, each of the 7840 patients received clinical exam and ultrasound. In the other group, 7689 received clinical exam alone or, if they had risk factors (abnormal exam, breech, family history, foot deformities), ultrasound and clinical exam. In the selective ultrasound group, 5 infants presented between 5–6 months with previously undiagnosed DDH, whereas in the universal screening group there was only 1 case of late diagnosis. In all these late-presenting cases, treatment with an abduction brace was implemented and the hips were reported to be normal upon follow-up. Overall treatment rates were equivalent in the two groups.

The second RCT48 included 629 patients who had been diagnosed with unstable hips on screening examination and were referred to 33 specialty centers in the United Kingdom (UK). The subjects were randomized within the specialty centers to receive ultrasonographic hip examination (n=314) or clinical assessment alone (n=315). A total of 90% of patients in the ultrasound group received an ultrasound in the first 8 weeks of life; 8% in the no-ultrasound group received an ultrasound. Compared to those in the ultrasound group, infants in the no-ultrasound group were treated more often (50% vs. 40%) and earlier (98/150 vs. 42/117 treated in the first 2 weeks of life). The need for surgical treatment (8% vs. 7%), age at surgical treatment (31 vs. 29 weeks), mean number of visits at outpatient clinics (4 in each), total hip-related hospitalizations (30 vs. 23) and the occurrence of definite or suspected avascular necrosis (5 vs. 8) were not significantly different between the two groups. Thus, despite a higher rate and earlier initiation of treatment in the clinical examination only group, the non-functional “outcomes” of the two groups were quite similar. This suggests that, in the specialty setting, clinical examination alone may lead to a greater degree of unnecessary treatment than that which occurs when an abnormal clinical examination is followed up with evaluation by ultrasound.

An earlier controlled trial, conducted in 1994, compared 3613 infants in a universal screening program to 4388 in a selective screening program, and 3924 who received only clinical examination.21 In the selective ultrasound cohort, a positive clinical examination was considered to be a risk factor prompting ultrasound. The study concluded that universal ultrasound had a significantly higher treatment rate overall, but no higher rate among high risk infants. There was a nonsignificant trend toward a lower rate of cases diagnosed after 1 month of age in the universal screening patients. Among those not treated, many more children with mildly dysplastic hips were identified by ultrasound, resulting in more follow-up visits and ultrasounds for a greater number of patients in the universal screening approach.

b) How does the age of the child affect screening parameters?

Irrespective of reference standard, the clinical exam approach to diagnosis for DDH shifts over time. Barlow and Ortolani tests become less sensitive as infants age, due to factors including increased strength, bulk, and size (Key Question 3b).1, 3 In their place, assessment of hip abduction becomes the preferred examination, because infants with dislocated hips have increased contractures of the hip adductors.3 Specificity of examination improves as infants' age, because the hips of the newborn infant are more likely to exhibit transient and clinically insignificant laxity than they will subsequently.11 Two recent studies provide indirect insight into the changing signs of DDH as the infant ages. In a study of 1071 referred infants at one center, only 2 of 34 (6%) hips in patients with positive Barlow or Ortolani tests, confirmed as dislocatable by ultrasound, had any limitation in abduction in patients at 1–2 weeks of age, suggesting poor sensitivity in newborns.76 Specificity of limited hip abduction in newborns was also poor. Among 203 1–2 week old infants with limited abduction, <20% had abnormalities on ultrasound. These findings contrasted with older children: of the eight patients who presented after six months of age with dislocatable hips, hip abduction was limited in 7 (87.5%). The second study, a prospective observational study limited to infants greater than 3 months of age (N=683), found that unilateral limited hip abduction had a sensitivity of 69% (156/226), and a specificity of 54% (247/457).77 The reference standard in this study was any ultrasound abnormality; among subluxable and dislocatable hips, sensitivity of limited hip abduction was > 82%. Of the patients with limited abduction and normal ultrasound findings (N=136), none showed any abnormalities on examination, and all walked normally without a limp at 5 years of age. Though not conclusive, these studies suggest that hip abduction is a relatively insensitive and nonspecific marker of DDH in early infancy, but becomes more accurate after 3–6 months of age and with more severely affected hips.

Additional physical examination findings sometimes linked to DDH include asymmetrical gluteal and thigh skinfolds, and leg length discrepancy. No studies from the past 40 years were identified which assessed the value of these findings in diagnosing DDH. Barlow pointed out the lack of utility of asymmetric skin folds due to their poor sensitivity and specificity,6 and Palmén studied 500 random newborns, finding that 27% had no thigh skinfolds, 40% were symmetrical, and 33% asymmetrical; 4 of these 500 babies had an abnormal provocative test of stability, of which 2 had symmetrical skinfolds.70

3c) How does the educational level and training of the screener impact screening?

The degree of training and experience with the clinical examination of the hip in infants has been shown to be a strong predictor of the test characteristics (Key Question 3c). Pediatricians have been shown to have a case identification rate of 8/1000, whereas orthopedists identify approximately 11/1000.2 In one single site longitudinal study, during periods when the number of pediatricians involved in the screening program increased (holding steady the number of newborns screened), a greater number of cases of DDH were missed despite an increased rate of suspected cases identified.78 This finding may suggest that screening accuracy suffers when an examiner has less ongoing experience in the exam technique. Two studies show that having duplicate blinded examinations by a pediatrician and an orthopedist improves the sensitivity, specificity, and predictive value of clinical exam screening.79, 80 Additional studies show that well-trained non-physicians, including physiotherapists and neonatal nurse practitioners, perform at least as well as physician examiners, and better than physician trainees.81–83

In several studies comparing pediatricians with orthopedic surgeons, the surgeons review a subset of hips found to be positive or questionable by the previous examiner. This may happen days after the initial examination. Also, the surgeons often have at their disposal the results of ultrasonography, and their clinical examination is not blinded from the ultrasound exam. Not surprisingly, such studies show a higher sensitivity and specificity of clinical examination in the hands of the specialist.

Key Question 4. What Are the Adverse Effects of Screening?

Dislocation. While it has been suggested that the examination of already-lax newborn hips might cause injury or dislocation,84 we identified little research that sought to test this hypothesis. Three studies provides some insights85–87 An autopsy study examined 10 hips in stillborn infants, 4 of them full term and one at 28 weeks gestation, and found that after repeated (up to 30) “forceful” Barlow maneuvers six of the hips became lax.85 Upon further study, it was determined that if the vacuum present in the joint capsule is disrupted, the hip becomes readily dislocatable.85 A study of examiners with varied exam experience, using an anatomic hip model for examination, found that the maximum force applied during the Barlow maneuver far exceeded the force necessary to dislocate the joint, across all levels of experience.86 A study with living patients used dynamic ultrasound to monitor laxity during 4 successive examinations with Barlow and Ortolani and found no increased laxity over the course of these exams.87 However, different examiners conducted each exam, so within-subject trends in stability were likely to reflect differences in examiners rather than changes in the joints themselves.87

Radiation Exposure. A single center study of radiation exposure and increased theoretical risk of fatal cancers or reproductive defects reviewed the radiographic history of 173 patients who completed a course of treatment for DDH between 1980 and 1993. Results showed that patients who had surgery (a marker for significantly more exposure) were calculated to have a 0.09% increased risk of fatal leukemia and a 0.23% increased risk of reproductive defects in males, and 0.12% and 0.5% increased risk, respectively, in females.88 There was no increased risk of fatal breast cancer in either gender. Attributable risks in nonsurgical patients were approximately 1/2 to 1/3 of those reported for surgical patients. Given changes in technology and management in the time interval since this data was gathered, it is not clear whether the level of radiation exposure documented in this study is still applicable.

Psychosocial. We found no published studies, but identified unpublished data from Drs. Frances Gardner and Carol Dezateau on the psychosocial impacts of screening and intervention for DDH in the UK Hip Trial. This data was not made available for this review.

No evidence was identified regarding adverse effects suffered by the child or family from false positive identification. Presumably, there is a cost borne by the family and/or society for the follow-up evaluation that ensues, but this has not been quantified. Other adverse effects may be experienced, but are not represented in the literature.

Key Question 5. Does Early Diagnosis of DDH Lead to Early Intervention, and Does Early Intervention Reduce the Need for Surgery or Improve Functional Outcomes?

Family/patient adherence. Underlying the effectiveness of early diagnosis and early intervention is the degree to which families adhere to medical recommendations. One study that met quality criteria assessed failure to follow-up with a specialty appointment after identification of newborns with an abnormality on exam or the presence of a risk factor for DDH.36 This specialty clinic, a part of Britain's National Health System, followed a systematic approach to contacting non-attenders, including up to 2 letters to the family explaining the reason for referral, safety of ultrasound, and offering an appointment the following week, followed by contact with the general practitioner to persuade the family. With this approach, nearly 95% of patients followed up. The groups with the highest follow-up rate, in excess 98%, included those with an unstable hip at the newborn exam and those with a positive family history. It may be unlikely to expect the average orthopedic clinic in the United States (US) to achieve an equivalent rate of follow-up, given established barriers to access and less robust efforts at contacting those who initially miss scheduled appointments.

A second study, based in the US, examined the rates of parental adherence to recommended abduction therapy with the Pavlik harness.89 Of 32 patients treated by the same physician, only 2 families reported strict adherence to the physician's orders in a post-treatment questionnaire. Nonadherence was defined as failure to do one or more of the following: a) full-time use during the initial period of reduction when the hip was not stable, b) altering or deliberating misplacing the harness, c) discontinuing use of the harness for prolonged periods of time without permission. Nearly two-thirds of the mothers in the study had a college education or advanced degree; their age range was 17–40 years (average age 29 years). Harness therapy failed in 3 out of the 32 patients, and by the authors' report these cases were not more egregious in their degree of noncompliance than successfully treated children. The single exception was a mother who routinely removed or adjusted the harness because the child could not fit into a car seat due to limited adduction.89

Effectiveness of interventions. A large number of nonsurgical abduction devices are represented in the published literature and an equally large number of surgical procedures are used to treat DDH (Appendix 1). The indications and timing of surgery, and the protocol for the selected treatment modality vary from site to site, further obfuscating attempts at clarifying effectiveness. These circumstances are characteristic of interventions that have not been evaluated, or proven effective, in controlled trials.90 Because no experimental or prospective cohort studies compare intervention with no intervention, the net benefits and harms of interventions for DDH are unclear, not only for infants diagnosed early but for all children.91

Table 6 summarizes intervention studies92–104 that included any assessment of functional outcomes, regardless of quality. In contrast to readily obtainable radiographic measurements of the bony anatomy of the hip joint (see below), poor functional outcomes from hip pathology may not manifest for decades. Thus, functional outcomes are not commonly measured. Even when measured, the effect of interventions on functional outcomes is unknown because of 1) the absence of an appropriate comparison cohort and 2) the substantial risk of bias stemming from short duration of follow-up, significant loss to follow-up, and/or nonstandardized, unblinded assessment methods without adequate rigor to ensure their validity (e.g. the surgeon's subjective report of the patient's function and pain). In the absence of direct evidence from controlled trials, the case for the effectiveness of early intervention rests on less secure grounds.

Biological plausibility. It is biologically plausible that putting hips in the hip socket would facilitate normal development. While they are retrospective, careful analyses of late-presentation cases provide convincing fair quality evidence that late-presentation dislocations are often accompanied by premature arthritis, indicating that, at least in some cases, untreated DDH can have serious consequences.105–107

Based on this information, it is reasonable to hypothesize that relocating hips long before clinical symptoms occur may prevent morbidity and improve function. Unfortunately, an understanding of the effectiveness of interventions for DDH is confounded by the fact that many unstable and dysplastic hips undergo spontaneous resolution.6 Thus, without a study design that includes an untreated cohort, the benefit attributable to an intervention remains in doubt.

Although the number of studies is small, it is clear that untreated DDH has an unpredictable course. Among 628 Navajo infants born in a single region from 1955 to 1961, 548 were examined and radiographed during the first four years of life (20% in the first 6 months of life, but none as neonates).108, 109 Eighteen (3.3% of those examined) were found to have hip dysplasia (including subluxation, but not including frank dislocation) by accepted radiographic criteria. None were treated. Seventeen of these 18 children were followed for seven to 19 years, and all had stable hips with normal x-rays.109 When 10 of these patients were followed up at 33–37 years of age, none were aware that they had ever had a problem with their hips. While 6 did report a history of mild hip pain, this did not correlate with the degree of abnormality on x-ray. Additionally, all patients had normal function, engaged in light to heavy labor and were able to contribute to society without limitations.108 Another study followed 51 consecutive patients with a normal clinical examination but evidence of dysplasia on x-ray. Altogether, 6 patients were lost over 5 years of follow-up. Forty-four affected hips (number of patients not reported) were normal after 5 years, 4 had undergone successful abduction therapy, and 20 were borderline on repeat imaging. No progression to subluxation or dislocation was noted in any of the hips.110

Reduced need for surgery. Early noninvasive intervention may reduce the need for surgery. This is a key observation that underlies several recommendations favoring screening for DDH. As discussed earlier, however (KQ1), the evidence supporting this assertion is conflicting. More over, the need for surgery is a moving target: when they are observed, reductions in surgical rates might have occurred because of changing indications or because of wider use of a period of observation prior to surgery, rather than because of screening itself.

Earlier intervention may reduce the risk of complications. In addition to studies summarized in Table 6, several observational studies examined the impact of age at the time of intervention (Key Question 5a).32, 45, 96, 111–114 In one small study that included children initiating therapy for DDH from birth through 4 months of age, duration of treatment increased in a dose response fashion as the age at initiation of treatment increased, holding the severity of DDH steady.45 In a separate series of patients undergoing surgery for DDH (70% of whom had failed therapy with a Pavlik harness), those 6–9 months of age (18 patients) required no additional corrective surgeries, whereas 29% of patients 10–11 months of age, 13% of patients 12–14 months of age, 26% of patients 15–18 months of age, and 30% of patients 19–24 months of age required additional surgical interventions.111 Another study, based upon unadjusted analysis, reported that the average age of DDH cases complicated by avascular necrosis was > 15 months, whereas uncomplicated cases averaged 11 months of age.112 Two additional studies found that intervention initiated after 6 months of age was associated with significantly higher rates of avascular necrosis.96, 113 In a study that focused on late diagnosis of DDH, closed reduction failed in a similar proportion of cases in children 0–3 months as those 3–6 months, but failed significantly more frequently after 6 months of age (no upper age limit could be identified in the latter category, potentially biasing these conclusions).114 Finally, a study of 55 children who underwent operative procedures for DDH between 1988 and 1998 found that while more children diagnosed under 3 months of age underwent surgery (no denominator data was available to provide a rate), the procedures were less invasive in children less than 6 months. All children greater than 12 months undergoing a procedure for DDH required an osteotomy, the most invasive procedure.32

In contrast, three retrospective observational studies did not support an effect of age on success of treatment.95, 115, 116 The first reviewed the rate of success of closed reduction, and showed no difference among patients treated with this intervention at less than 6 months, 7–12 months, or 13–18 months.115 Next, a study limited to 168 children with hip subluxation or dislocation and a minimum follow up of 5 years, compared children in whom a Pavlik harness was successful with those requiring closed reduction and those who eventually required open reduction, and found that age was not a predictive factor of the success of nonsurgical therapy.116 Finally, a study of 75 children with DDH treated within the first 14 weeks of life with the Pavlik method showed that age at initiation (ranging from 5 to 13 weeks) had no influence on duration of treatment, success rate, or AVN outcome at 1 year of age.95

It is possible that some relevant literature was excluded because we limited the review to studies in children less than 1 year of age. However, within this age range, conclusive evidence of a clear benefit of earlier intervention is elusive. The design of the studies cannot exclude other plausible explanations for the association between age at intervention and rates of surgery. One of these explanations is that passive abduction therapy may be less effective as children become stronger and more mobile beyond 6 months of age. Another is that the early-treated group includes a high proportion of children with mild disease that would have recovered without intervention, while the older children have severe disease that would not have responded had they been treated earlier.

Improved radiographic appearance. Use of noninvasive treatments is often associated with improvements in radiographic or ultrasonographic appearance. While radiographic reduction may be an essential step in the causal pathway from congenital dislocation to prevention of serious complications, radiographic outcomes have not been shown to be valid or reliable surrogates for functional outcomes. The most commonly used and widely accepted radiographic assessment is a 6-level scale initially described by Severin in 1941, based upon radiological appearance of hips in 16–24 year olds.117 No studies attempted to validate the Severin classification. One study examined patients who had received surgery for dislocation of the hip, at an average of 31 years post-intervention.118 The study found that x-ray findings (normal position of femoral neck and head, degree of arthritis and shape of the femoral head) were poorly correlated with the outcomes of range of motion and pain. Despite uncertain validity, several studies applied the Severin criteria to patients outside the range of the original 16–24 year old target population, including those not yet skeletally mature.

Two studies assessed the reliability of the Severin classification.119, 120 Ali et al found intraobserver reliability among pediatric orthopedists in the UK with 7 or more years experience to be moderate to substantial (kappa ranging from .58 to .77), and interobserver reliability to be poor to slight in the intermediate Severin classes of II and III (kappa 0.19 to 0.20) and moderate (kappa 0.44 to 0.54) in the disparate Severin classifications of I (normal) and V (marginal dislocation). Unfortunately, “good” outcomes are typically classified as Severin II,91 one of the grades found to have the poorest inter-observer reliability. A study by Ward found even less reassuring results.120 Blinded assessments by pediatric orthopedists in this study were assessed by dichotomous observer groups as well as multi-rater groups, and found kappa scores in the range of 0.0 to 0.29 across the range of Severin classes, and no higher than 0.56 for overall agreement across any two surgeons. Even more concerning, the operating surgeons' unblended scores showed uniform poor reliability (kappa 0.02 to 0.21) when compared to each of the blinded observer's scores. Despite uncertain reliability, intervention studies rarely included blinded or repeated assessments of radiographic outcomes. Due to highly suspect validity and reliability, studies that reported only radiographic outcomes were excluded from further review.

Closer follow-up. Diagnosis leads to attentive follow-up of infants with DDH, facilitating quick detection and intervention. Thus, children undergoing early noninvasive therapy may benefit from closer follow-up and the physician's ability to react to a deteriorating condition more rapidly. As discussed above, available evidence supports the notion that a high proportion of families follow through with initial referral. However, we could not determine how many families adhere to ongoing follow-up.

Key Question 6. What Are the Adverse Effects of Early Diagnosis and/or Intervention?

Good quality literature examining harms of intervention for DDH would include a comparison of 2 or more (ideally randomized) cohorts, each exposed to a standardized intervention and followed over sufficient time (with limited loss to follow-up) to ensure complete ascertainment of the potential harms with an assessment of the effect of the measured harms on patient outcomes. Unfortunately, these studies have not yet been conducted. In their absence, we reviewed the fair quality literature on adverse effects of both nonsurgical and surgical interventions.

The most well described adverse effect from interventions aimed at treating DDH is AVN of the femoral head. This is the most common adverse effect for both abduction therapy and surgical interventions. AVN severity ranges from a persistent but asymptomatic radiographic finding to a severe condition that causes growth arrest and can lead to eventual destruction of the joint. The rates described in the literature for this adverse effect vary greatly for abduction therapy as well as surgical interventions. (Figure 5).92–96, 98, 100, 102–104, 113, 121–129 The reasons for these disparate findings are not straightforward, and most likely relate to a complex and confounded set of variables including but not limited to the wide spectrum of the disorder, heterogeneous populations studied (age at intervention, specific type of DDH, previous interventions received), the variety of interventions and the poorly standardized approach to interventions (particularly the pre- and post-intervention phase of management), variable training and talent among the treating physicians, different lengths of follow-up across studies, and disparate approaches to follow-up in different health care systems. As calculated in the AAP review, meta-analytic rates of AVN range from 13.5 – 109/ 1000 infants who undergo treatment (non-surgical vs. surgical rates not specified).2

Figure

Figure 5. Range of Published Rates of Avascular Necrosis Data Sources.

Figure

Figure 5a. Avascular Necrosis Data Sources.

Additional harms from abduction therapy that have been addressed in the literature are typically mild and self-limited, and include rash, pressure sores, and femoral nerve palsy. All surgical interventions carry the risks inherent in general anesthesia, and those that involve open surgery also include the generic surgical risks of infection, excessive bleeding, and wrong site surgery, though these receive scant review in the published literature and thus cannot be quantified.

A fair quality study assessing the long-term psychological impact on children of successfully treated DDH showed that parents and teachers found that children with DDH were more “disordered” than peers with no hospitalizations, 1 hospitalization, and multiple hospitalizations on measures of health, habits, and behavior.130 This study which took place in 1983, implies (but does not quantify) extended hospitalizations for these children as a rule, and thus may not be generalizable to the impact of treatment today.

Key Question 7. What Cost-Effectiveness Issues Apply to Screening for DDH?

Several economic analyses of screening for DDH have been published.48, 91, 131–136 Most concern the marginal benefit of ultrasound screening in relation to screening with clinical examination.48, 91, 132, 133, 136 None of the available studies used quality adjusted life years, and none used models based upon U.S. data or the U.S. health care system. These analyses demonstrate that the economic impact of ultrasound screening is complex, reflecting that ultrasound may have mixed effects on diagnosis of DDH: it may identify false positive clinical examinations, reducing or shortening the duration of unnecessary treatments, but it also identifies many abnormalities in infants who have normal physical examinations, potentially leading to more early treatment and greater follow-up costs. The mixed results of the economic studies largely reflect mixed results of the clinical studies on which they are based. The best quality economic study, derived from a RCT (in the UK) of clinical exam screening versus clinical exam plus ultrasound, maintained detailed records of utilization of medical services and related costs.48 The authors concluded that the overall direct medical costs for the two approaches were not statistically significantly different.48 This study did not report indirect costs, such as missed work by the family, nor did it include the costs of long-term follow-up or complications.

Which action by the nurse demonstrates the correct technique of assessing for arm recoil?

Which action by the nurse demonstrates the correct technique of assessing for the popliteal angle?

Which method should a nurse use when assessing respirations in a newborn?

Which principle of child development should guide the nurse's decisions when planning the assessment of a child to best minimize stress?