Echography of the hip of the newborn infant

The authors report on their experience with 2164 US exams of the hip performed over last year on newborns, according to Graf's technique. The babies were divided into 2 groups at first examination: risk/no risk. We considered as risk factors: a positive family history, malposition in utero, abnormalities at birth, and being one of twins. Hips 2a+ and 2a- according to Graf were grouped as "borderline hips" (BLH), extrapolating them from negative and positive cases. BLH have generally shown a tendency to spontaneous normalization, although worsening of the condition was observed in 7.9% of cases. A high incidence of positivity (5.1%) was observed in the no-risk group, versus 9% in the risk group. Moreover, there was low agreement between clinical examination and US findings: the need for US screening is therefore pointed out, not only to promptly detect a decentered hip, but also to prevent the development of juvenile coxarthrosis in case of dysplasia. Premature babies were also studied, and those underweight for their gestational age: the incidence of positive subjects in this group (4.5%) was not higher than that found in the no-risk group (5.1%). We report on the phases of hip normalization as related to stage and therapy. Graf's technique, besides being at present the only reproducible one, represents a method common to all radiologist which allows hip measuring and staging.     

Echography of the hip in premature infants]

The authors report the data relative to 50 preterm infants with gestational age less than or equal to 34 weeks. The newborns were studied sequentially with clinical and US examination from February 28, 1989 to March 23, 1990 in order to exclude hip dysplasia or dislocation. US examination was carried out according to Graf's technique. All the newborns had another clinical examination at one year of age in order to evaluate their normal walking. Risk factors had poor significance in the studied group of infants.     

Anterior dynamic ultrasound and Graf's examination in neonatal hip instability

Background: Discrepancy between neonatal hip morphology and stability has been reported in the literature. Comparative ultrasound studies on this issue are limited.

Purpose: To compare neonatal hip instability, as assessed by dynamic ultrasound and clinical examination, with acetabular morphology, as assessed by Graf's method.

Material and Methods: 536 newborn infants with clinical signs of hip instability, ambiguous findings at clinical hip examination, or positive risk factors for DDH were investigated with two ultrasound methods, the Graf method and anterior dynamic ultrasound, at an average age of 12 days. The hips were allocated to three groups according to the Graf result: A, normal (type Ia and b); B, borderline or immature (type IIa); and C, pathologic (type IIc and worse). Graf examination was compared with two diagnostic tests for instability, namely clinical examination by senior pediatric orthopedists and anterior dynamic ultrasound.

Results: According to Graf's method, 77% of the hips were normal, 20% borderline/immature, and 3% pathologic. On clinical hip examination, 82% were stable, 14% unstable, and 4% dislocatable. The dynamic ultrasound outcome was 88% stable hips, 10% unstable, and 2% dislocatable. Of the hips considered unstable or dislocatable on dynamic ultrasound, 21% had normal (type I) and 66% immature acetabular morphology according to the Graf method. Of the hips that were stable on dynamic ultrasound, only one (0.1%) was dysplastic according to the Graf method. Graf's examination showed the smallest number of normal hips, but also the fewest pathologic hips, with many indeterminate results that needed follow-up.

Conclusion: Acetabular morphology correlated better to stability as assessed by dynamic ultrasound than to the clinical examination results, with fair to moderate agreement. Graf's examination resulted in a large number of indeterminate results that needed follow-up, but when used as the sole criterion for deciding treatment did not lead to a higher treatment rate than when the decision was based on clinical hip examination.     

Echography in the study of the neonatal hip: the diagnostic-therapeutic implications of type-IIa (borderline) findings]

Sonography (US) is a useful method in the early diagnosis of congenital hip dislocation; X-ray examination exhibits limitations due to high false-positive and false-negative rates. The advantages of US include: non-invasiveness, direct visualization of muscle and cartilage, dynamic demonstration of anatomical structures, and possible diagnosis in neonatal age. Therefore, US can be used as a screening or targeted diagnostic technique in selected newborns with clinical suspicion and/or risk factors. In this paper the authors report their experience in 1271 patients (721 females, 550 males), aged 1 day to 7 months, who were examined with US for the diagnosis of congenital hip dislocation. The newborns were divided into two groups at first examination: a) the screening group included 524 consecutive newborns (F = 266, M = 258) from S. Chiara Regional Hospital in Trento, and b) a selected group of 747 newborns (F = 455, M = 292) with clinical suspicion and/or risk factors, who had been selected in the Trento area. According to Graf's classification, the results of US in 2542 neonatal hips, were: 2346 (92.3%) normal hips, 171 (6.1%) type IIa hips, and 24 (1.6%) pathological hips. In the selected group (1494 hips) we observed: 1351 (90.4%) normal, 119 (8%) type IIa, and 24 (1.6%) pathological hips (IIb, IIc, D, III). In the screening group (1048 hips) we detected: 995 (95%) normal hips (Ia/Ib), 52 (4.9%) type IIa, and 1 (0.1%) pathological hips (D). Our experience suggests that US is a useful method in selected newborns with clinical suspicion of congenital hip dislocation and/or risk factors. US limitations consists in the dispersion of type IIa hips. Moreover, the need emerged for complete cooperation between pediatrician, radiologist, and orthopedist to optimize the cost/benefit ratio.     

Neonatal hip: from anatomy to cost-effective sonography

Therapeutic success in treating congenital dysplasia of the hip is associated with early diagnosis, but the specific neonatal anatomy makes screening difficult. The purpose of this study was to determine whether this specific neonatal anatomy is taken into account by current ultrasound (US) techniques. Anatomic studies were performed on 22 hips, US examinations on 7750 neonatal hips; 2370 untreated hips were reexamined at 1 month by US and at 3 months by X-ray. The transformation of the neonatal cartilaginous acetabulum into an osseous cavity is dependent on harmonious metaphyseal growth and a properly seated femoral head. Defects in the acetabular roof, together with displacement of the femoral head, cause an abnormal anatomical relationship which leads to further deformities. The described sonographic techniques give only partial information on these specific abnormalities. The sonographic monoplanar methods as used in Graf's technique, which relies largely on acetabular development, lead to difficulties in assessing posterior coverage of the femoral head and difficulties in assessing alignment of the metaphyseal weight-bearing surface with the femoral head. Combining Graf's morphological analysis with Novick's dynamic technique enables one to more accurately define the relationship of the femoral head and the acetabulum and increases the reliability and predictive value of the examination, while reducing the number of doubtful cases. This makes screening cost effective. Received: 20 February 1997; Revision received: 28 August 1997; Accepted: 7 January 1998     

Neonatal screening and follow-up of congenital hip luxation using echography. Review of the literature and personal contribution on 1421 newborns

US screening for hip dysplasia was performed on 1421 full-term newborns. The study was aimed at: 1) evaluating US feasibility in an unselected maternity ward population; 2) determining the frequency of the different types of hips, and correlating ours with literature data; 3) evaluating the efficacy of both an early prevention and treatment. All US examinations were performed within the first week of life and the 2842 hips classified according to Graf. At birth, normal hips (Ia, Ib) were 2064 (72.6%) (group I); physiologically immature hips (IIa) were 721 (25.4%) (group II); pathological hips (group III) were: 43 (1.5%) IIc, 8 (0.3%) IId, 6 (0.2%) III. Hips in group B were checked at 3 months: 502 were normal, 51 were type IIb, and 1 was type IId: the latter 52 hips were treated and normalized in the following months. Hips in group C (types IIc, IId, and III = 57 hips) were treated and checked every seventh week until normalization. Our experience confirms US value in the evaluation of hip dysplasia in the newborn. In our opinion, the use of this method should be encouraged, although US screening of all newborns remains controversial on a cost-benefit ratio. Multicentric studies will better define US sensitivity, specificity and reliability. The correlation of our results with literature data was difficult, because study populations are not always homogeneous. As for therapy, we found the plastic splint very effective and easy to use. In 2 cases, Milgram devices were used for a few months.     

Initial results from an ultrasound screening program for the detection of developmental dysplasia of the hip in girls

Purpose

To determine the value of US screening for detection of developmental dysplasia (DDH) in girls in the setting of a multi-disciplinary program in pediatric orthopedics.

Materials and methods

Systematic US evaluation of the hips using the Couture technique was performed at 1 month in all girls with normal physical examination at birth over a 1 year period. The examinations were classified as normal or abnormal (DDH [acetabular depth > 6 ], asymmetrical pelvis, borderline hips). Results were correlated with risk factors and clinical outcome. Girls with abnormal hips were immediately treated.

Results

One thousand one hundred and sixty-six girls were screened. A total of 4.7% of ultrasound examinations were abnormal. The rate of pathological hip was 3.7% in the absence of risk factors and 8.9% in the presence of risk factors. A total of 63.6% of girls with abnormal ultrasound examination had no risk factor. Two risk factors were correlated to the presence of DDH: family history (RR = 3.12) and clinical abnormalities (RR = 2.55). The rate of pathological hip that were referred for treatment was 3.1%. All hips were normal at 5 months.

Conclusion

Ultrasound screening evaluation of the hip in girls at 1 month, in the setting of a multi-disciplinary program in pediatric orthepedics clinic, is feasible. A total of 74 abnormal hips undetected at the initial clinical evaluation in girls without risk factor were detected and treated. Systematic screening of girls for DDH must be further assessed to better determine its impact on the incidence of delayed diagnosis of DDH.     

Echography in hip dysplasia in neonates and infants. Echographic anatomy, technic and case material

The value of hip joint sonography in newborns and unweaned infants is the latest development in the diagnosis of hip dysplasia. Knowledge of the sonographic anatomy makes accurate examination and staging according to Graf's tables possible. Since sonography is non-invasive it can be used for screening and check-up, thus reducing the use of radiography. A personal series of 250 patients is presented.     

婴儿发育性髋关节发育不良早期筛查的情况分析

目的分析临床结合超声检查对婴儿发育性髋关节发育不良(developmental dysplasia of the hip,DDH)进行早期筛查的结果,为DDH早期干预提供科学依据,降低DDH的致残率。方法对我院筛选DDH体征阳性4896例患儿行超声进一步检查。结果体格检查可疑阳性婴儿4896例,经过超声检查,正常髋关节3591例,占73.3%(3591/4896),可疑异常髋关节1196例,占24.5%(1196/4896),异常髋关节109例,占2.2%(109/4896),其中脱位型髋关节7例,占0.14%(7/4896)。对确诊患儿进行临床治疗,106例异常髋关节转为Graf I型髋关节,治愈率达97.2%(106/109)。结论对婴儿髋关节进行早期筛查对提高婴儿DDH检出率有重要意义,对确诊患儿给予早期干预可促使发育异常的髋关节结构向正常的髋关节转化,改善婴儿髋关节功能,具有重要的经济意义与社会意义。     

Ultrasonographic study of the hip joint in infants

We performed ultrasonography screening for the hip joint in 145 infants between January 2003 and January 2004 at Nakajo-machi in Niigata Prefecture. This ultrasonographic study was conducted by Graf's method. The method could discriminate normal hip joints and was able to visualize 11 abnormal hip joints as well. All abnormal hip joints were dysplastic. This method is more useful than x-ray examination for infants, since the cartilaginous femoral head and the soft tissues around the hip could be clearly visualized. As a result, ultrasonography appears to be a useful screening method for congenital dislocation of the hip joint, without the hazard of radiation caused by x-rays.     

Congenital luxation of the hip. Clinico-echographic correlations

The authors report their experience with US of the hip in 1000 children aged 1 day to 8 months. US study was carried out following Graf's method. All the children were previously examined by a pediatrician, who recorded all the clinical signs on a chart. After US examination, the radiologist recorded US findings on the same chart. Thus, US findings could be compared to clinical ones: there was agreement in 71% of cases, and disagreement in the extant 29%. Furthermore, clinics exhibited a high false-negative rate (64%) and a low false-positive rate (23%). This suggests US as an useful screening method able to show early morphological and functional alterations in the infant hip. The authors also examined the incidence of the single clinical signs and risk factors, and correlated them with US findings.     

Role of echography in the diagnosis and treatment monitoring of congenital acetabular dysplasia. Personal experience with 2000 examined children

Since 1987 the authors have used sonography (US) as the means to detect dysplasia and congenital dislocation of infant hips, to define severity of the disease, and to monitor the results during treatment. In this paper the authors report their experience in 2000 examined babies. In 20 young patients, mainly females, 25 pathologic joints were detected and classified as 2c-4 hips. Orthopedic treatment employed Pavlick harness and, in case of partial success, Milgram abduction pillow too. This treatment has always been successful, except for a case with severe dislocation with echostructural changes in the acetabular cartilage. In this case, surgery was necessary. "Delayed ossification" (type 2b hips) and physiological immatury (type 2a hips) with alpha angle greater than or equal to 55 degrees were not splinted in abduction: normal maturity has always been attained without dysplastic involutions. Our experience confirmed US value in the early diagnosis of congenital acetabular dysplasia, when clinics exhibited evident limitations. Nonetheless, management and economical problems are still to be solved, due to the relationship of the widespread use of US in infant population and to its successful results, also considering the low incidence of the examined pathologic condition.     

Congenital hip dislocation. The clinico-echographic correlations

The authors report their experience with US of the hip in 200 children aged 9 days to 8 months. All the children previously were under-gone physical examination. The sonographic study was carried out with Graf's method. The clinical-sonographic correlation proves the utility of US as a screening method able to show early morphological and functional alterations in the hip. US is thus suggested as a valid alternative to conventional methods to use in those cases where either plastering or surgery is required.     

Ultrasonic investigation of the hip in newborns in the diagnosis of congenital hip dislocation: classification and results of a screening program

Summary The method of ultrasonic examination of the hip is described, the latest updated Graf classification is explained, and the results of a prospective screening program are described. One thousand four hundred and sixty newborn infants were examined by ultrasound and clinically by independent observers. The distribution of the ultrasound types was determined. Recommendations are given for the use of ultrasonic investigation of the hip for groups at risk in the neonatal period.     

Neonatal hip instability: a prospective comparison of clinical examination and anterior dynamic ultrasound

Background: Ultrasound is increasingly being used to complement the clinical examination in assessing neonatal hip instability. The clinical examination, although highly sensitive in detecting hip instability, can lead to considerable overtreatment.

Purpose: To compare anterior dynamic ultrasound and clinical examination in the assessment of neonatal hip instability and regarding treatment rates.

Material and Methods: 536 newborn infants (out of a population of 18,031) were selected, on the basis of a combination of risk factors, clinical signs of hip instability or ambiguous clinical findings, to undergo an anterior dynamic ultrasound examination of the hip, by a method developed by our group. This examination, performed by one out of seven experienced examiners, was compared with the standard clinical hip examination conducted by one of four pediatric orthopedic surgeons. The clinical examination was carried out both prior to and within a few hours after the ultrasound examination.

Results: The clinical examination diagnosed 81.7% of the hips as normal, 14.5% as unstable, and 3.8% as dislocatable or dislocated. With the dynamic ultrasound method, the corresponding figures were 87.8%, 10.4%, and 1.8%, respectively. Use of the criteria of the clinical examination resulted in treatment of 147 infants. Using the dynamic ultrasound examination as a criterion meant that 87 infants would receive treatment. The calculated treatment rate was 0.85% when based on the clinical stress test and 0.49% when based on the dynamic ultrasound.

Conclusion: The dynamic ultrasound results reduced the treatment rate by over 40% when used as a basis for the decision regarding treatment.     

Echographic anatomy of the newborn hip and high-resolution equipment: internal capsular stria and perichondrial gap

The use of high-resolution US equipment in the examination of the newborn hip allowed the evaluation of a thin echogenic stripe (the internal capsular stripe), which defines laterally the acetabular hyaline cartilage. By means of an anatomo-histological preparation the echogenic stripe can be related to either the capsular circular fibres or the interface between the latter and the hyaline cartilage. The internal capsular stripe, together with the echogenic synovial stripe, precisely delimit the whole acetabular hyaline cartilage. Furthermore, in many babies high-resolution US sometimes fails to demonstrate Graf's "perichondral gap", so that an accurate anatomic knowledge of the hip becomes necessary in the evaluation of acetabular labrum.     

Reliability of ultrasonography in the follow-up of hip dysplasia in children above 2 years of age

PURPOSE: The aim of the present study was to assess whether ultrasonography (US) was reliable in the follow-up of children above 2 years of age who had previously been treated for congenital or developmental hip dislocation or dysplasia (HD). MATERIAL AND METHODS: As part of the routine follow-up, we examined 53 children (106 hips), aged 2-12 years (mean 6 years). Using US, the coverage of the femoral head was assessed by the distance from the lateral tangent of the ossified femoral head to the lateral bony acetabular rim (lateral head distance, LHD). The corresponding distance was measured on radiographs (LHDR). The radiographic femoral head coverage was assessed by the migration percentage (MP) and the center-edge (CE) angle. RESULTS: We found a good accordance between sonographic LHD and the radiographic parameters MP and CE in all age groups, indicating that femoral head coverage was reliably assessed by US. There was also a high correlation between LHD and LHDR (r=0.85). All hips with subluxation were detected by US. In 11 hips that appeared normal on US, but with dysplasia or uncertain findings by radiography, the condition spontaneously normalized in 9 out of 9 examined hips with further follow-up. CONCLUSION: Because a reliable assessment of the hip is obtained, we recommend that US should be used as the primary imaging technique in the routine follow-up of children above 2 years of age with previous HD. Radiography should be omitted when US shows normal findings and is only needed when the US LHD is above the upper normal limit or the hip looks abnormal or suspicious by subjective evaluation.     

Morphological analysis of the knee joint in patients with hip dysplasia

Purpose

The purpose of this study was to investigate the morphological changes of the knee in patients with untreated developmental dysplasia of the hip.

Methods

Morphological analysis of 150 knee joints in 75 patients with developmental dysplasia of the hip was performed by examining computed tomographic (CT) images. Of these patients, 36 had unilateral developmental dysplasia of the hip and 39 had bilateral developmental dysplasia of the hip. Therefore, 36 hips were normal, and 114 hips were dislocated. CT images ranged from the iliac crest to 2 cm inferior to the tibial tuberosity.

Results

Compared with the knees in patients with normal hips, the femoral condyles in patients with dislocated hips were smaller and exhibited greater medial and lateral condylar asymmetry. The anterior femoral condylar angle of the femur was increased, as was the groove angle, while the trochlear groove was shallower in patients with dislocated hips. Furthermore, the lateral patella shift was reduced and the patellar tilt angle was increased in patients with dislocated hips compared with patients with normal hips. The extent of changes in these variables differed with the degree of dislocation. However, the posterior condylar angle of the femur was not affected by the degree of dislocation.

Conclusion

These findings suggest that developmental dysplasia of the hip is associated with morphological changes in the knee joint. These changes should be considered during hip and knee surgery.

Level of evidence

Prospective study, Level II.     

Ultrasound in the diagnosis of developmental dysplasia of the hip in newborns. The European approach. A review of methods, accuracy and clinical validity

Based on soft evidence that ultrasound screening tends to reduce the rate of late developmental dysplasia of the hip (DDH) and the need for surgical interventions, different screening strategies including universal or selective ultrasound screening have been established in several European countries and centres during the last decade. We performed an extensive search for articles on ultrasound diagnosis of developmental dysplasia of the hip over the last 26 years. A few studies reported an adequate repeatability for the static [Graf, Morin, modified Morin (Terjesen)] and for the combined static/dynamic methods [modified Graf (Rosendahl)], while no such reports were found for the dynamic (Harcke) ultrasound techniques. The effect of newborn ultrasound screening on late DDH have been addressed in two randomised trials (RCTs), both concluding that both selective and universal ultrasound screening tend to reduce the prevalence of subluxed or dislocated DDH, thus without reaching statistical significance. Finally, several observational studies have shown that morphologically normal hips tend to remain normal with or without a co-existing instability, and 97% of sonographically immature hips tend to normalise spontaneously within 3 months. Two studies report on a similar pattern for mildly dysplastic, but stable hips. From the data available we suggest that selective ultrasound screening is worthwhile in areas with a high prevalence of late cases, given a well-organised, high-quality service can be provided.     

Diagnostic errors in the echography of the hip in newborns

Neonatal hip sonography according to Graf employs a standardized image in a frontal section plane ("3-point system") and a good scanner adjustment (the femoral head must be anechoic, like the hyaline cartilage roof triangle). Pathologic conditions can change some of these parameters. The authors examined 6,000 neonatal hips in order to point out the commonest causes of diagnostic error. Two types of error were considered: method errors and interpretation errors. Method errors: they are due to the choice of transducer and frequency, to scanner adjustment and definition of the standard section plane. Their incidence was 2.25% and supported by an uncorrect definition of the standard section plane. Interpretation errors: they come from the wrong localization of some reference points--i.e., lower iliac margin, labrum--, uncorrect evaluation of increased echogenicity of the cartilaginous roof, infant age, application of radiographic criteria and uncorrect measurements of alpha and beta angles. Interpretation errors had 5.5% incidence; they were all due to the uncorrect measurement of alpha (3.18%) and beta (2.33%) angles, especially in pathological hips (68%). To reduce the number of errors, the authors suggest to strictly apply Graf's method, to make a diagnosis based on the morphological changes of the cartilaginous and osseous acetabular roof and, only later on, to measure alpha and beta angles to confirm the diagnosis or in the follow-up.