Ultrasonography for evaluation of hip dysplasia. Methods and policy in neonates, infants, and older children

Risk factors of developmental dysplasia of the hip in infants: A meta-analysis based on cohort studies

INTRODUCTION

Developmental dysplasia of the hip (DDH) is a prevalent condition in children. Currently, the exact etiology of DDH remains uncertain. The objective of this study was to conduct a meta-analysis to investigate the risk factors associated with DDH in infants. The findings would provide a theoretical foundation for targeted early screening and diagnosis.

HYPOTHESIS

Several indicators, such as gender, intrauterine position, family history of DDH, gestational age, delivery mode, amniotic fluid levels, swaddling, parity, fetus number, combined musculoskeletal deformities, birth weight, and physical examination results, may serve as risk factors for DDH.

MATERIALS AND METHODS

Cohort studies investigating the risk factors of DDH in infants through logistic regression analysis were searched in the Wanfang, VIP citation, China National Knowledge Infrastructure (CNKI), China Biology Medicine disc, Excerpta Medica Database (Embase), PubMed, and Cochrane Library databases up to May 2023. After extracting the data from eligible literature and assessing them using the Newcastle-Ottawa Scale (NOS), articles were selected based on pre-established inclusion and exclusion criteria.

RESULTS

A total of eleven literature reports covering 979,757 infants were included in this meta-analysis. The publication bias did not significantly influence the results. The incidence rate of DDH was 47.99‰ among infants with risk factors compared to 3.21‰ in the general population. Risk factors for DDH included being female (OR=6.97, 95% CI: 5.18-9.39, p<0.001), breech delivery (OR=4.14, 95% CI: 3.09-5.54, p<0.001), positive family history (OR=4.07, 95% CI: 2.20-7.52, p<0.001), cesarean section (OR=1.11, 95% CI: 1.01-1.21, p=0.032), oligohydramnios (OR=3.93, 95% CI: 1.29-12.01, p=0.016), swaddling (OR=6.74, 95% CI: 1.25-36.31, p=0.026), firstborn status (OR=1.84, 95% CI: 1.49-2.53, p<0.001), combined musculoskeletal malformations (OR=2.27, 95% CI: 1.58-3.27, p<0.001), and physical signs of DDH (OR=8.71, 95% CI: 2.44-31.07, p=0.001). Premature delivery (OR=0.91, 95% CI: 0.88-0.95, p<0.001) was a protective factor for DDH. The relationship between multiple pregnancies (OR=0.58, 95% CI: 0.33-1.02, p=0.060) and low birth weight (OR=0.62, 95% CI: 0.14-2.76, p=0.529) in relation to DDH remained uncertain.

DISCUSSION

This meta-analysis shows that female, breech delivery, positive family history, cesarean section, firstborn status, oligohydramnios, swaddling and combined musculoskeletal malformations are associated with DDH. Premature delivery appeared to be a protective factor against DDH. Nevertheless, the other factors need more research to reach more conclusive results.

LEVEL OF EVIDENCE

III; meta-analysis.

Developmental dysplasia of the hip: impact of sonographic newborn hip screening on the outcome of early treated decentered hip joints-a single center retrospective comparative cohort study based on Graf's method of hip ultrasonography

PURPOSE/BACKGROUND/INTRODUCTION: The aim of this study was to retrospectively evaluate the impact of neonatal sonographic hip screening using Graf's method for the management and outcome of orthopaedic treatment of decentered hip joints with developmental dysplasia of the hip (DDH), using three decades (1978-2007) of clinical information compiled in a medical database.

METHODS

Three representative cohorts of consecutive cases of decentered hip joints were selected according to different search criteria and inclusion and exclusion parameters: (1) cohort 1 (1978-1982; n = 80), without sonographic screening; (2) cohort 2.1 (1994-1996; n = 91), with nationwide established general sonographic screening according to the Graf-method; (3) cohort 2.2 (2003-2005; n = 91), with sonographic screening including referred cases for open reduction from non-screened populations. These three cohorts were compared for the following parameters: age at initial treatment, successful closed reduction, necessary overhead traction, necessary adductor-tenotomy, rate of open reduction, rate of avascular necrosis (AVN) and rate of secondary acetabuloplasty.

RESULTS

The age at initial treatment was reduced from 5.5 months in the first cohort to 2 months in the two subsequent two cohorts and the rate of successful closed reduction increased from 88.7 to 98.9 and 95.6%, respectively. There was a statistically significant improvement in six out of seven parameters with sonographic hip screening; only the rate of secondary acetabuloplasty did not improve significantly.

CONCLUSION

Compared to the era before the institution of a sonographic hip screening programme according to the Graf-method in Austria in 1992, ultrasound screening based-treatment of decentered hip joints has become safer, shorter and simpler: "safer" means lower rate of AVN, "shorter" means less treatment time due to earlier onset and "simpler" means that the devices are now less invasive and highly standardized.

Ultrasonographic findings in hips with a positive Ortolani sign and their relationship to Pavlik harness failure

BACKGROUND

In developmental dysplasia, Pavlik harness treatment of hips with a positive Ortolani sign fails in up to 40% of such patients; however, no study has described factors for failure associated with ultrasonographic parameters. The goal of this study was to describe unique ultrasonographic markers in hips with a positive Ortolani sign that are associated with Pavlik harness failure.

METHODS

A retrospective review was performed of all patients less than six months old who were treated for developmental dysplasia of the hip with a Pavlik harness from 1991 to 2005 at a single institution. Inclusion criteria for this study were patients with a hip that was dislocated but reducible (a positive Ortolani sign), treatment with a Pavlik harness, and an ultrasound examination performed within four weeks after the initiation of treatment. The initial coronal ultrasound studies were graded with use of the Graf classification, the percentage of femoral head coverage, labral morphology, and two new measurements: superior femoral head displacement relative to the labrum and total femoral head displacement.

RESULTS

Eighty-five patients with 115 hips fitting the inclusion criteria were identified. Pavlik harness treatment was successful in seventy-two hips (63%) and failed in forty-three hips (37%). Increased beta angle, decreased femoral head coverage, an inverted labrum, decreased superior femoral head displacement relative to the labrum, and decreased total femoral head displacement were significantly correlated with Pavlik harness failure (p < 0.001 for all). A finding of 0 degrees of superior femoral head displacement relative to the labrum was seen in 98% of the hips with successful Pavlik harness treatment. Total femoral head displacement of less than -30 degrees was found in 89% of the hips with a failure of Pavlik harness treatment.

CONCLUSIONS

We identified two new objective measurements on static ultrasound examinations of the hip that are associated with the outcome of Pavlik harness treatment in patients with developmental dysplasia and a positive Ortolani sign. A femoral head positioned below the labrum is strongly associated with success of the Pavlik harness treatment, whereas a hip with a femoral head that is located substantially superior and lateral to the labrum is associated with Pavlik harness treatment failure. The presence of a deficient cartilaginous anlage and an inverted labrum may provide a pathoanatomical explanation for Pavlik harness treatment failure.

[When is the optimal time for hip ultrasound screening?]

The perfect time for hip screening is when every pathologically deformed hip can be diagnosed by sonography and after spontaneous resolution of immature, dysplastic hips. In addition, the beginning of therapy should be early enough to provide the best possible outcome concerning the anatomically correct healing of the patient's hip. Even though every child should be screened by sonography in the first few days of life, a reasonable way could be ultrasound screening in the first week for clinically unstable hips or newborns with risk factors such as breech position combined with ultrasound screening of every newborn between the fourth and sixth week.

Diagnosis of congenital hip dysplasia in the newborn

BACKGROUND AND PURPOSE

Screening of newborn infants for congenital hip dysplasia may be done by clinical examination, ultrasound, or radiography--or a combination of these. Studies that have used clinical examination followed by ultrasound imaging for infants with certain risk factors have shown excellent results, but they were performed by very experienced practitioners. We wanted to find out whether the results of such screening would be equally good with less optimal staffing. Thus, we evaluated the real-life performance of a screening program for detection of congenital hip dysplasia in newborn infants.

SUBJECTS AND METHODS

We performed a retrospective chart review of all infants (n = 1,983) referred for evaluation for suspected congenital hip dysplasia from one single obstetric hospital, where 19,820 infants had been screened from 1992 through 2001. Infants were referred either because of a positive finding during the Ortolani and Barlow examinations or because of the presence of risk factors.

RESULTS

The reasons for referral of the 1,983 infants (10% of those examined) were: positive clinical signs in 255 (1.3% of all examined) and risk factors in 1,547 (7.8%), and a combination of both in 114 (0.6%). 67 other infants (0.3%) who had passed the initial pediatric screening were later referred from the local health centers. Finally, 23 of the 1,983 infants were subsequently referred again by their health center for renewed orthopedic evaluation. Of the infants who were treated (298/1,983 = 15% of those referred), those with a pathological examination result were represented proportionately more than infants who were referred because of risk factors (0.8% as opposed to 0.5%). Delayed diagnoses occurred in 1.7/1,000 infants.

INTERPRETATION

The performance of a screening protocol for congenital hip dysplasia in a real-life setting involving several physicians both on the pediatric and orthopedic side may not live up to expectations based on the use of such a protocol in an optimized setting. This type of analysis of screening data may serve to pinpoint weaknesses, and thus lead to adjustments that may enhance quality.

Residual dysplasia after successful Pavlik harness treatment: early ultrasound predictors

The purpose of this study was to evaluate a group of children treated with Pavlik harness for developmental dysplasia of the hip (DDH) to determine early ultrasound characteristics that predict poor acetabular development after walking age. From a group of 487 infants with DDH, 55 met inclusion criteria of (1) ultrasound documentation of major neonatal hip instability, (2) treatment with Pavlik harness, and (3) a minimum of 4 years of follow-up. These 55 infants had 100 abnormal hips. Harness treatment alone was successful in treating 87 of 100 hips. Persistent or late acetabular dysplasia was defined from serial radiographs. At a mean follow-up of 5.3 years, 5 of the 87 (6%) were found to have sequelae (late acetabular dysplasia, avascular necrosis of the femoral head, or both). Three sonographic findings present on the initial ultrasound predicted late sequelae: (1) dynamic coverage index of 22% or less, (2) alpha angle less than 43 degrees, and (3) abnormal echogenicity of the cartilaginous roof on initial ultrasound. Abnormal echogenicity was the most specific single predictor of residual dysplasia (sensitivity 100% and specificity 88%). The structurally normal cartilaginous roof is non-echogenic except for a short triangular fibrous tip (the labrum). Pathologic cartilage becomes echogenic beyond the tip as hyaline cartilage becomes fibrous and deformed. In unstable hips that respond well to Pavlik harness treatment, it would appear that midterm acetabular development can be affected when early transformation of roof cartilage accompanies displacement and instability.

Longitudinal study of normal hip development by ultrasound

In the management of a newborn's hips, ultrasonography has proven to be useful. The progression of measurements at different ages in normal hips has not been thoroughly investigated. The purpose of this prospective study was to assess the longitudinal development of clinically stable hips. Forty newborns (80 hips) were assessed by ultrasonography at birth and at 6 and 12 weeks of age. Femoral head coverage (FHC), alpha angles, and beta angles were measured. The results showed a significant change in values between the three points in time for all measurements (P < 0.001). The mean FHC progressed from 58.4% to 65.6% to 69.3%, the mean alpha angle from 70.2 degrees to 76.8 degrees to 80.3 degrees , and the mean beta angle from 52.1 degrees to 45.7 degrees to 42.9 degrees . In clinically stable hips, the FHC and alpha and beta angles change significantly over time; therefore, it is important to consider the child's age when interpreting ultrasound images.

Evaluation of ultrasonographic angle and linear parameters in the diagnosis of developmental dysplasia of the hip

Angle parameters proposed by Graf and linear parameters introduced by Morin are the most common currently in use for quantification and classification of ultrasonographic findings in the diagnosis of developmental dysplasia of the hip. The aim of this study was to determine which of the two parameters is more suited to routine clinical use. Investigation was carried out on 100 hips of 50 infants by the same examiner who obtained two separate sonograms for each hip. Based on the results of our study, angle parameters appear to be more functional in identifying and classifying pathology, and more adequate for screening and diagnosis.