Comparison between Graf method and pubo-femoral distance in neutral and flexion positions to diagnose developmental dysplasia of the hip

Assessing Femoral Head Medialization in Developmental Hip Dysplasia Type 1 and Type 2 Hip Separation

BACKGROUND/OBJECTIVES

The prevalence of developmental hip dysplasia is estimated to be 0.1-2 per 1000 infants. Hip imaging by ultrasonography is considered to be the gold standard method for screening and detecting developmental dysplasia of the hip (DDH), as per the Graf categorization. The classification of hip differentiation into type 1 and type 2 is determined by the alpha angle, as assessed by the Graf classification. Type 1 hips are defined as those with an alpha angle exceeding 60 degrees, whilst type 2 hips are defined as those with measurements falling within the range of 50 to 59 degrees.

METHODS

The computerized patient card in our institution had a compilation of 208 hip photographs taken from 110 patients, with 98 of them being bilateral. The acquisition of these photos occurred from January 2020 to December 2020. A retrospective review was conducted on the ultrasound (US) scans, with a specific emphasis on the outcomes related to type 1 and type 2 hips.

RESULTS

There were 108 high-resolution US photos in the type 1 hip group and 100 high-resolution US images in the type 2 hip group. In terms of unilateral or bilateral cases, gender, or age, no statistically significant differences were seen between the two groups (p > 0.05). The FMD model exhibited a sensitivity of 86% and specificity of 70% in effectively predicting the presence of type 1 mature hips when the values surpassed 2.9 mm. The AUC (area under the curve) value achieved was 0.628.

CONCLUSIONS

The process of diagnostic categorization may occasionally encounter challenges in accurately differentiating between type 1 and type 2 hip separation subsequent to a hip ultrasound examination. The findings of our analysis indicate that the assessment of the FMD is a highly successful method, demonstrating both high specificity and sensitivity in differentiating between various scenarios.

Pubofemoral distances correlate to acetabular morphology and sonological instability in screening for hip dysplasia

Aims

The present study seeks to investigate the correlation of pubofemoral distances (PFD) to α angles, and hip displaceability status, defined as femoral head coverage (FHC) or FHC during manual provocation of the newborn hip < 50%.

Methods

We retrospectively included all newborns referred for ultrasound screening at our institution based on primary risk factor, clinical, and PFD screening. α angles, PFD, FHC, and FHC at follow-up ultrasound for referred newborns were measured and compared using scatter plots, linear regression, paired t-test, and box-plots.

Results

We included 2,735 newborns, of whom 754 received a follow-up hip ultrasound within six weeks of age. After exclusion, 1,500 hips were included for analysis. Sex distribution was 372 male and 380 female, and the mean age at examination was 36.6 days (4 to 87). We found a negative linear correlation of PFD to α angles (p < 0.001), FHC (p < 0.001), and FHC during provocation (p < 0.001) with a 1 mm increase in PFD corresponding to a -2.1° (95% confidence interval (CI) -2.3 to -1.9) change in α angle and a -3.4% (95% CI -3.7 to -3.0) change in FHC and a -6.0% (-6.6 to -5.5) change in FHC during provocation. The PFD was significantly higher with increasing Graf types and in displaceable hips (p < 0.001).

Conclusion

PFD is strongly correlated to both α angles and hip displaceability, as measured by FHC and FHC during provocation, in ultrasound of newborn hips. The PFD increases as the hips become more dysplastic and/or displaceable.

Natural progression of the pubofemoral distance with age and its correlation with future acetabular index

OBJECTIVES

This study investigated the progression of pubofemoral distance (PFD) with age and assessed the correlation between PFD and late acetabular index (AI) measurements.

METHODS

This prospective observational study was conducted between January 2017 and December 2021. We enrolled 223 newborns who underwent the first, second, and third hip ultrasounds, and pelvis radiograph at a mean age of 18.6 days, 3.1 months, 5.2 months, and 6.8 months, respectively. The difference between PFD measured at serial ultrasounds and the correlation with AI were analyzed.

RESULTS

The PFD increased significantly (p < 0.001) at serial measurements. The mean PFD at the first, second, and third ultrasounds were 3.3 (2.0-5.7), 4.3 (2.9-7.2), and 5.1 (3.3-8.0) mm, respectively. The PFD at three ultrasounds were all significantly (p < 0.001) and positively correlated with AI, with the Pearson correlation coefficients being 0.658, 0.696, and 0.753 for the first, second, and third ultrasounds, respectively. Using AI as reference, the diagnostic ability of PFD was calculated by the areas under the receiver operating characteristic curve, which was 0.845, 0.902, and 0.938 for the first, second, and third PFD, respectively. For the first, second, and third ultrasounds, PFD cutoff values of ≥ 3.9, ≥ 5.0, and ≥ 5.7 mm, respectively, yielded the greatest sensitivity and specificity in predicting late abnormal AI.

CONCLUSION

The PFD naturally progresses with age and is positively correlated with AI. The PFD has potential for predicting residual dysplasia. However, the cutoff for abnormal PFD values may require adjustment according to the patient's age.

KEY POINTS

• The pubofemoral distance measured in hip ultrasonography naturally increases as the infant's hips mature. • The early pubofemoral distance demonstrates a positive correlation with late acetabular index measurements. • The pubofemoral distance may help physicians predict abnormal acetabular index. However, the cutoff for abnormal pubofemoral distance values may require adjustment according to patient's age.

Artificial Intelligence-Assisted Ultrasound Diagnosis on Infant Developmental Dysplasia of the Hip Under Constrained Computational Resources

OBJECTIVES

Ultrasound (US) is important for diagnosing infant developmental dysplasia of the hip (DDH). However, the accuracy of the diagnosis depends heavily on expertise. We aimed to develop a novel automatic system (DDHnet) for accurate, fast, and robust diagnosis of DDH.

METHODS

An automatic system, DDHnet, was proposed to diagnose DDH by analyzing static ultrasound images. A five-fold cross-validation experiment was conducted using a dataset containing 881 patients to verify the performance of DDHnet. In addition, a blind test was conducted on 209 patients (158 normal and 51 abnormal cases). The feasibility and performance of DDHnet were investigated by embedding it into ultrasound machines at low computational cost.

RESULTS

DDHnet obtained reliable measurements and accurate diagnosis predictions. It reported an intra-class correlation coefficient (ICC) on α angle of 0.96 (95% CI: 0.93-0.97), β angle of 0.97 (95% CI: 0.95-0.98), FHC of 0.98 (95% CI: 0.96-0.99) and PFD of 0.94 (95% CI: 0.90-0.96) in abnormal cases. DDHnet achieved a sensitivity of 90.56%, specificity of 100%, accuracy of 98.64%, positive predictive value (PPV) of 100%, and negative predictive value (NPV) of 98.44% for the diagnosis of DDH. For the measurement task on the US device, DDHnet took only 1.1 seconds to operate and complete, whereas the experienced senior expert required an average 41.4 seconds.

CONCLUSIONS

The proposed DDHnet demonstrate state-of-the-art performance for all four indicators of DDH diagnosis. Fast and highly accurate DDH diagnosis is achievable through DDHnet, and is accessible under constrained computational resources.

Pubo-Femoral Distances Measured Reliably by Midwives in Hip Dysplasia Ultrasound

The pubo-femoral distance (PFD) has been suggested as an ultrasound screening tool for developmental dysplasia of the hip (DDH). The aim of this study was to examine if midwives undergoing minimal training could reliably perform pediatric hip ultrasound and PFD measurements. Eight recruited midwives performed two rounds of independent blinded PFD measurements on 15 static ultrasound images and participated in four supervised live-scanning sessions. The midwives were compared to a group of three experienced musculoskeletal radiologists. Reliability was evaluated using inter-rater correlation coefficients (ICC). Linear regression was used to quantify the learning curve of the midwives as a group. There was near complete intra- and inter-rater agreement (ICC > 0.89) on static ultrasound images across both rounds of rating for midwives and radiologists. The midwives performed a mean of 29 live hip scans (range 24−35). The mean difference between midwives and supervising radiologists was 0.36 mm, 95% CI (0.12−0.61) for the first session, which decreased to 0.20 mm, 95% CI (0.04−0.37) in the fourth session. ICC for PFD measurements increased from 0.59 mm, 95% CI (0.37−0.75) to 0.78 mm, 95% CI (0.66−0.86) with progression in sessions. We conclude that midwives reliably perform PFD measurements of pediatric hips with minimal training.

Use of ultrasonography to evaluate early outcomes of reduction in developmental dysplasia of the hip

OBJECTIVE

To compare pubo-femoral distance (PFD) in normal hips and those treated for developmental dysplasia of the hip (DDH) and to investigate the value of ultrasonography from the medial hip in early follow-up of dislocated DDH after reduction.

MATERIALS AND METHODS

This study included 58 infants (49 females) with DDH who presented with 65 dislocated hips (51 unilateral and 7 bilateral). Dislocation was treated by closed reduction for 53 and open reduction for 12 hips. Ultrasonography on the medial side of the hip was performed within 1-2 weeks and 4 weeks after reduction. The distance from the pubic bone to the femoral head (PFD) was measured to assess the reduction and stability of the femoral head and compared to that on the contralateral side (control) in cases of unilateral DDH.

RESULTS

The PFD value for the normal group (2.9 ± 0.4 mm) was significantly less than that for the closed reduction group (4.9 ± 2.8 mm, P<0.001) and that for the open reduction group (4.4 ± 1.6 mm; P=0.02), but no difference in the PFD was observed between the closed reduction and the open reduction groups (P=0.73). Despite successful reduction, the PFD values in the successful reduction group remained higher than those of the normal hips.

CONCLUSION

PFD measurement by ultrasonography of the medial hip can be used to evaluate the effectiveness of reduction procedures in DDH. The clinical implications of post-reduction ultrasound evaluation in the diagnosis and long-term follow-up of outcomes require further research.

Measurement of Pubofemoral Distance in the Diagnosis of Developmental Dysplasia of the Hip: Sensitivity and Specificity

OBJECTIVES

To evaluate the accuracy of measurement of the pubofemoral distance (PFD) for the diagnosis of developmental dysplasia of the hip (DDH), using the Graf method as the reference standard.

METHODS

This was a prospective diagnostic accuracy study evaluating 1980 hips in at-risk neonates. The PFD measurement and the Graf method were performed at the same opportunity, with the hips in the same position (slightly flexed, adducted, and medially rotated).

RESULTS

In our sample, the prevalence of DDH, defined as Graf type IIb or higher, was 15.6%. The mean PFD for dysplastic hips was 3.5 mm (median, 3.3 mm), whereas it was 3.0 mm (median, 2.9 mm) for nondysplastic hips. In both groups, there was a significant overlap between the PFD measurements and the Graf classifications. The PFD cutoff with the largest area under the receiver operating characteristic curve was 3.0 mm, which was found to have a sensitivity and specificity of 63.6 and 62.2%, respectively, with positive and negative predictive values of 31.2 and 71.4%, respectively, for the diagnosis of DDH.

CONCLUSION

Measurement of the PFD shows good overall accuracy for the diagnosis of DDH. However, given its low-positive predictive value, it should not be considered to be a replacement for the Graf method.

Predictivity of International Hip Dysplasia Institute classification in Pavlik harness treatment and correlation with Graf ultrasonographic classification

Hip ultrasonography applied according to Graf's criteria is frequently used in early diagnosis and monitoring of developmental dysplasia of the hip (DDH). Recently, the International Hip Dysplasia Institute (IHDI) classification has been proposed to be a prognostic indicator for patients with walking-age DDH. The purpose of this study is to evaluate the reliability of IHDI classification in the follow-up of patients with DDH diagnosed by ultrasonography scanning. A total of 69 hips of 38 patients (10 men, 28 women; mean age 59.9 ± 19.8 days, range 29-90 days) were diagnosed with DDH younger than 90 days of age. The AP pelvis radiographs of the patients who were diagnosed with DDH by ultrasound and classified according to the Graf method were evaluated and classified according to IHDI classification. A total of 52 hips were treated successfully with Pavlik harness treatment, 15 hips underwent closed reduction and pelvipedal casting (PPC) and 2 hips underwent open reduction and PPC after failed Pavlik harness treatment. Increasing IHDI grades correlated with the failure of Pavlik harness treatment (P = 0.001). Graf classification was not found to be predictive of successful Pavlik harness treatment (P = 0.482). There was no significant correlation between the IHDI classification and the Graf classification (Kappa = 0.079 ± 0.102, P = 0.402). The IHDI method is reliable in predicting the success of Pavlik harness treatment in patients diagnosed with DDH using the Graf method.

Ultrasound techniques for the detection of developmental dysplasia of the hip: a systematic review and meta-analysis

BACKGROUND

Developmental dysplasia of the hip (DDH) encompasses a broad spectrum of hip pathologies, including femoral or acetabular dysplasia, hip instability, or both. According to the medical literature, ultrasonography is the most reliable diagnostic method for DDH. Several techniques for the assessment of hips in newborns and infants, using ultrasonography, have been described.

OBJECTIVE

To compare the accuracy of the Graf technique and other diagnostic techniques for DDH.

DESIGN AND SETTING

A systematic review of studies that analyzed ultrasound techniques for the diagnosis of DDH within an evidence-based health program of a federal university in São Paulo (SP), Brazil.

METHODS

A systematic search of relevant literature was conducted in the PubMed, EMBASE, Cochrane Library, CINAHL, and LILACS databases for articles published up to May 5, 2020, relating to studies evaluating the diagnostic accuracy of different ultrasound techniques for diagnosing DDH. The QUADAS 2 tool was used for methodological quality evaluation.

RESULTS

All hips were analyzed using the Graf method as a reference standard. The Morin technique had the highest rate of sensitivity, at 81.12-89.47%. The Suzuki and Stress tests showed 100% specificity. The Harcke technique showed a sensibility of 18.21% and specificity of 99.32%.

CONCLUSION

All the techniques demonstrated at least one rate (sensibility and specificity) lower than 90.00% when compared to the Graf method. The Morin technique, as evaluated in this systematic review, is recommended after the Graf method because it has the highest sensitivity, especially with the three-pattern classification of 89.47%.

REGISTRATION NUMBER

Identifier: CRD42020189686 at the International Prospective Register of Systematic Reviews (identifier: CRD42020189686).

Pulvinar and pubic cartilage measurements to refine universal ultrasound screening for developmental dysplasia of the hip: Data from 1896 infant hips

PURPOSE

Screening modalities for Developmental Dysplasia of the Hip (DDH) and indications for treatment of mild forms remain controversial. Ultrasound (US) measurement of the pubofemoral distance (PFD > 6 mm, composed of the pubic cartilage and the pulvinar) can avoid late diagnoses of DDH. A thick pubic cartilage may nevertheless lead to false positives. The purpose of this study was to establish standard measurements of pubic cartilage and pulvinar, through universal US screening, to lower false positive results and thus any overtreatment.

METHODS

This is a single-center observational prospective study conducted from December 2016 to January 2018, on infants who underwent universal US screening for DDH. The only inclusion criterion was an adjusted age between 4 and 12 weeks when US was realized. PFD measurement was made using the Couture and Tréguier method. In addition, thicknesses of pubic cartilage and pulvinar were measured on the same US section, in millimeters.

RESULTS

Nine hundred and forty-eight patients, representing 1896 hips, were included. The average value of pubic cartilage thickness was 1.25 mm ± 0.58 mm, with an upper threshold of 2.39 mm (+1.96σ). The average value of pulvinar thickness was 2.67 mm ± 0.78 mm, with an upper threshold of 4.20 mm (+1.96σ). We found high inter-observer reproducibility in pubic cartilage measurements.

CONCLUSION

Systematic measurements of pubic cartilage and pulvinar may refine therapeutic decision by identifying false positives. Patients with increased PFD due to a thick pubic cartilage >2,39 mm, without an associated pulvinar enlargement (<4,20 mm), could be therefore only monitored and not overtreated.

Establishing reference values for the pubofemoral distance in normal infant medial hips by ultrasound

BACKGROUND

Measuring the pubofemoral distance (PFD) is important for evaluating the effectiveness of hip reduction in the treatment of developmental dysplasia of the hip (DDH). However, reference PFD values have not been established in normal infants.

PURPOSE

To investigate variations in PFD values measured in normal infant medial hips stratified by age, laterality, and gender.

MATERIAL AND METHODS

A total of 240 infants diagnosed with Graf type Ia and/or Graf type Ib hips by ultrasonography were stratified into eight age groups: 0-1 month; 1-2 months; 2-3 months; 3-4 months; 4-5 months; 5-6 months; 6-7 months; and 7-12 months. The bilateral medial hips were scanned with transinguinal ultrasound. The PFD was defined as the distance between the lateral edge of the superior ramus of pubic bone and the medial edge of the femoral head. Inter-observer reproducibility was assessed.

RESULTS

Among the 240 infants, there were 371 Graf type Ia hips and 109 Graf type Ib hips. Mean ± SD bilateral PFD values of eight groups were measured separately. There were no significant differences in mean PFD values for left or right hips (t = 0.946, P = 0.345) or mean bilateral PFD values in male and female infants (t = 1.445, P = 0.149). Mean PFD values increased linearly with age (left: r = 0.680, P < 0.0001; right: r = 0.682, P < 0.0001). Inter-observer reproducibility was excellent.

CONCLUSION

This study established reference PFD values from the medial hip in infants aged 0-12 months. PFD values increased with age, but were not significantly influenced by laterality or gender. These data provide detailed information that can support follow-up of infants treated for DDH.

Coronal Flexion Versus Coronal Neutral Sonographic Views in Infantile DDH: An Important Source of Variability

BACKGROUND

Ultrasound (US) is the preferred imaging modality for the diagnosis and treatment of infantile developmental dysplasia of the hip (DDH). Currently accepted indices that distinguish normal from dysplastic hips in the coronal plane include percent femoral head coverage (FHC), α angle, and β angle. Recent data suggests that significant user and interscan variability may exist for these metrics. Less studied, however, is potential variability because of patient positioning, specifically coronal flexion versus coronal neutral views. The purpose of this study was to compare standard DDH indices between coronal US views with hips in flexion versus neutral positions, for hips of varying DDH severity.

METHODS

This retrospective study included normal infants and those treated for different severities of DDH. Coronal flexion and coronal neutral US images from the same study were evaluated at diagnosis, early treatment, start of weaning, and treatment resolution. FHC, α, and β angles were measured on both views at each time point and compared. Inter-rater and intra-rater reliability assessments were performed for all metrics.

RESULTS

Among the 168 hips in this study (45 normals, 45 Ortolani positive, 17 Barlow positive, and 61 stable dysplasia), median FHC was significantly lower in coronal flexion compared with coronal neutral for normals and all 3 severities of DDH at each time point (mean decrease 8.4%; range 5.5% to 10.9%; P<0.01). Alpha angle also decreased on coronal flexion views, observed for all hip types, but only at certain time points (mean decrease 3.3 degrees; range 0 to 7.5 degrees; P<0.01 to 0.35). β angles demonstrated less variability between views, but also had poor reliability.

CONCLUSIONS

Coronal flexion and coronal neutral views demonstrated significant differences in FHC and α angle across a spectrum of DDH severities and treatment time points. Flexion views may represent a "baby Barlow" test, revealing subtle instability as evidenced by the significant and consistent decrease in FHC across all hips. Indices measured in flexion, therefore, may represent more stringent criteria for defining normal hips.

LEVEL OF EVIDENCE

Level III-diagnostic study.

Optimizing the Time for Developmental Dysplasia of the Hip Screening: Earlier or Later?

INTRODUCTION

Developmental dysplasia of the hip (DDH) is still a common and important disorder of childhood, with a prevalence of 0.1 to 2/1000 children. Using ultrasonography (US) in screening of DDH reduces the rates of open reductions and complications. In the current study, we aim to detect the optimal time for US examination for detecting DDH to prevent unnecessary repeating US examinations and treatments.

METHODS

Children referred to US examination for a healthy child screening program, according to the health policy of our country, are included in the current prospective study. Both hips of each child were sonographically examined by the same radiologist using Graf's method at 4th, 8th, 12th weeks of life.

RESULTS

A total of 2020 hips of 1010 children were examined. Fourth-week US results can predict 12th-week results (right hip: sensitivity 100%, specificity 75.7%; left hip: sensitivity 100%, specificity 78.3%). Eighth-week US results can predict 12th-week results (right hip: sensitivity 100%, specificity 87.5%; left hip: sensitivity 100%, specificity 83.9%). In predicting 12th-week US results, 8th-week results are found to be more successful than 4th-week results.

CONCLUSIONS

Late diagnosis of DDH might cause serious public health problems. On the other hand, early US examinations can result in false-positive diagnosis. Unfortunately, there is still confusion about the optimal time for DDH screening with US, especially among radiologists who are not specialized in DDH sonography. A US scan performed at eighth week of life can predict any pathology presence safely and correctly.

Suggestion for new 4.4 mm pubo-femoral distance cut-off value for hip instability in lateral position during DDH screening

Background and purpose - Current selective screening algorithms for developmental dysplasia of the hip (DDH) are insufficient. Universal screening programs have been proposed but so far have been deemed too expensive and time consuming. The pubo-femoral distance may solve this problem as a quick, low-cost, highly sensitive, and specific sonographic measurement for DDH, but this has only been validated in the supine position. Therefore we validated pubo-femoral distance (PFD) in the lateral position as an indicator for instability of the hip. Methods - All participants had undergone ultrasonographic diagnostics using the modified Graf technique. In addition, PFD measurements in lateral position were performed. Results were compared between 25 infants who had been treated for DDH because of dysplastic appearance on ultrasound combined with clinical instability and a control group consisting of 100 untreated infants screened for DDH. Sensitivity, specificity, and cut-off points were determined using Receiver operating characteristics (ROC) analysis. Results - We found a mean PFD of 6.8 mm (6.2-7.4) in the treated group with a control group PFD of 3.4 mm (3.3-3.6) (p < 0.005). A PFD value above a threshold of 4.4 mm yielded a sensitivity of 100% and a specificity of 93% for detecting unstable DDH. Interpretation - PFD measured in lateral position was statistically significantly increased in hips of children treated for DDH with Denis Browne hip brace compared with healthy children with unaffected stable hips. Furthermore, the PFD measurement had a high level of sensitivity and specificity at a cut-off value of 4.4 mm. A cut-off value of 6.00 mm has previously been reported as the gold standard in supine position. We suggest that 4.4 mm is used in lateral position.

Exploration of femoral head coverage in screening developmental dysplasia of the hip in infants

PURPOSE

To investigate the relationship of femoral head coverage (FHC) with Graf's classification for diagnosis of developmental dysplasia of the hip (DDH) and its role in evaluating hip stability.

METHODS

A total of 4222 hips were screened ultrasonographically with Graf's and Harcke's methods. The stability of hips was analyzed using the difference between FHCs at neutral and flexion positions (FHC-D).

RESULTS

(1) For the non-dislocated hips, the mean value of FHC at the neutral position was 59.4%, which was significantly greater than 55.0% of FHC at the flexion position (p < 0.001). (2) FHC at the neutral position corresponding to Graf I, IIa/b, IIc, D, III, and IV was 63.0 ± 4.7%, 57.0 ± 5.2%, 49.5 ± 5.5%, 37.7 ± 3.7%, 30.2 ± 12.7%, and 7.4 ± 11.9%, respectively, and that at the flexion position was 59.0 ± 4.4%, 50.7 ± 9.4%, 35.2 ± 5.2%, 30.8 ± 1.3%, 23.4 ± 10.7%, and 4.7 ± 9.9%, respectively, showing a statistically significant difference between the two positions. (3) The AUC of FHC-D in evaluating the stability of hips was 0.972. When the threshold was 8.5%, the sensitivity, specificity, and accuracy of FHC-D in detecting hip instability were 89.0%, 93.0%, and 93.9%, respectively.

CONCLUSIONS

FHC can be used as a reference indicator for DDH classification. FHC at different positions corresponds to different reference values, and FHC-D can be used as a quantitative indicator for assessment of hip stability.

The pubo-femoral distance decreases with Pavlik harness treatment for developmental dysplasia of the hip in newborns

OBJECTIVE

To evaluate the evolution of the ultrasonographic pubo-femoral distance (PFD) before and after Pavlik harness treatment for developmental dysplasia of the hip (DDH) in newborns.

PATIENTS AND METHODS

Twenty-five patients (16.7 ± 10.4 days; 19 females, six males) diagnosed with DDH and treated using the Pavlik harness were included. Eighteen patients had bilateral, and seven unilateral DDH, with a total of 43 dysplastic hips. The seven non-dysplastic hips in unilateral cases were used for comparison. The PFD was measured in the coronal and axial planes with the hip flexed to approximately 90°, before and after an average of 93 days of treatment. The femoral head coverage was assessed in the coronal plane, and correlated with PFD values.

RESULTS

In dysplastic hips, the mean PFD decreased from 6.1 ± 1.8 mm to 3.0 ± 0.7 mm in the axial (adjusted difference, 2.9 mm; p < 0.01), and from 5.9 ± 2.0 to 3.0 ± 0.6 mm in the coronal plane (adjusted difference 2.7 mm; p < 0.01). The femoral head coverage increased from 30.8 to 62.1%, and the mean differences of femoral head coverage and PFD were significantly correlated (p < 0.001). There was no difference between treated dysplastic and non-dysplastic hips. There was high intra- and inter-observer agreement for PFD measurements.

CONCLUSION

The PFD decreased significantly after DDH treatment using the Pavlik harness in newborns, and showed significant correlation with the femoral head coverage improvement. PFD might be a reliable tool for monitoring DDH treatment in newborns treated using the Pavlik harness.

Clinical evaluation of ultrasound screening in follow-up visits of infants with cerebral palsy at high risk for developmental dysplasia of the hip

The aim of the study was to assess the clinical value of ultrasound screenings for the developmental dysplasia of the hip (DDH) and explore its etiology in high-risk infants with cerebral palsy in follow-up visits. A group of 98 cases of infants at high-risk of cerebral palsy who received rehabilitation treatment between July, 2009 and July, 2010 were selected. Infants included 58 men and 40 women, aged <6 months and not lost to follow-up visits. Ultrasound (using Graf static inspection) screening of hips was performed and the infants with abnormalities were given clinical intervention, and 1- to 2-year-old infants were given outpatient follow-ups. The results were analyzed and there were 40 abnormal cases among the 98 cases of infants at high risk of cerebral palsy, including 18 cases of unstable hip joint, and 22 cases of DDH (12 cases of hip dysplasia, 3 cases of hip subluxation and 7 cases of hip dislocation). Early clinical intervention for infants with hip dysplasia and outpatient follow up for infants aged 1–2 years was carried out and had ischemic necrosis of femoral head, with the exception of 1 case of femoral detorsion that was poorly restored. In conclusion, the probability of DDH was higher in infants at high-risk of cerebral palsy compared to the normal infants. Hip ultrasound is a safe, simple, and effective screening method for these infants, which is of great clinical significance for an earlier diagnosis and treatment of DDH in infants with cerebral palsy.