Abduction treatment in stable hip dysplasia does not alter the acetabular growth: results of a randomized clinical trial

Spontaneous recovery in the majority of stable dysplastic hips treated with active surveillance

Aims

Worldwide controversy exists on the optimal treatment of stable dysplastic hips. The most common treatment options are abduction brace treatment and active surveillance. The primary aim of this study was to assess the effect of active surveillance in stable hip dysplasia, by investigating the percentage of Graf IIb stable dysplastic hips that recover spontaneously without abduction brace treatment. The second aim was to identify prognostic factors for spontaneous recovery of stable dysplastic hips.

Methods

A single-centre, prospective cohort study was conducted at the Máxima Medical Center between 1 March 2019 and 1 March 2023. Infants aged three to 4.5 months at the first outpatient clinic visit, diagnosed with Graf IIb hip dysplasia, and treated with active surveillance were included. Spontaneous recovery was defined as infants who had a normalized hip on ultrasound (α-angle ≥ 60°) after six weeks of active surveillance without receiving abduction brace treatment. Baseline infant characteristics and ultrasound measurements were used as potential predictor variables for spontaneous recovery in logistic regression analyses.

Results

A total of 508 infants with Graf IIb stable dysplastic hips were included. Overall, 473 infants (93.1%) recovered spontaneously with active surveillance. Of the remaining 35 infants, 25 infants (4.9%) received six weeks and ten infants (2.0%) received 12 weeks of additional Pavlik harness treatment until hip normalization. In univariate and multivariate analyses, an impaired hip abduction was negatively associated (OR 0.43 (95% CI 0.20 to 0.93); p = 0.033) and being a firstborn child positively associated (OR 2.20 (95% CI 1.04 to 4.63); p = 0.042) with spontaneous recovery.

Conclusion

The majority of Graf IIb stable dysplastic hips recover spontaneously in infants aged three to 4.5 months after six weeks of active surveillance. We recommend active surveillance with ultrasound as primary treatment for these infants. However, care must be taken with active surveillance in infants with a limited hip abduction.

Universal ultrasound screening and early treatment of developmental dysplasia of the hip: a critical review

Developmental dysplasia of the hip (DDH) is the most common musculoskeletal disease in infants, and delayed diagnosis can worsen the prognosis. Clinical evidence increasingly supports universal ultrasound (US) screening over selective US screening. The Graf method remains the most widely accepted US technique. Performing an US screening at one month of age seems appropriate as it allows for some hip maturity and early detection, thereby increasing the chances of a favorable outcome. This paper presents an approach to US findings based on the femoral head coverage method. Considering the long-term cost and psychosocial impact of missed DDH cases, universal ultrasound screening appears to be a cost-effective alternative.

Bimodal machine learning model for unstable hips in infants: integration of radiographic images with automatically-generated clinical measurements

Bimodal convolutional neural networks (CNNs) are frequently combined with patient information or several medical images to enhance the diagnostic performance. However, the technologies that integrate automatically generated clinical measurements within the images are scarce. Hence, we developed a bimodal model that produced automatic algorithm for clinical measurement (aaCM) from radiographic images and integrated the model with CNNs. In this multicenter research project, the diagnostic performance of the model was investigated with 813 radiographic hip images of infants at risk of developmental dysplasia of the hips (232 and 581 images of unstable and stable hips, respectively), with the ground truth defined by provocative examinations. The results indicated that the accuracy of aaCM was equal or higher than that of specialists, and the bimodal model showed better diagnostic performance than LightGBM, XGBoost, SVM, and single CNN models. aaCM can provide expert's knowledge in a high level, and our proposed bimodal model has better performance than the state-of-art models.

Comparison of brace to observation in stable, radiological developmental dysplasia of the hip: a protocol for a global multicentre non-inferiority randomised trial

INTRODUCTION

Brace treatment is common to address radiological dysplasia in infants with developmental dysplasia of the hip (DDH); however, it is unclear whether bracing provides significant benefit above careful observation by ultrasound. If observation alone is non-inferior to bracing for radiological dysplasia, unnecessary treatment may be avoided. Therefore, the purpose of this study is to determine whether observation is non-inferior to bracing for infants with radiological dysplasia.

METHODS AND ANALYSIS

This will be a multicentre, global, randomised, non-inferiority trial performed under the auspices of a global prospective registry for infants and children diagnosed with DDH. Patients will be included if they present with radiological dysplasia (centred hip, alpha angle 43-60°, percent femoral head coverage greater than 35% measured on ultrasound) of a clinically stable hip under 3 months old. Patients will be excluded if they present with clinical hip instability, have received prior treatment or have known/suspected neuromuscular, collagen, chromosomal or lower-extremity congenital abnormalities or syndromic-associated hip abnormalities. Patients will be enrolled and randomised to undergo observation alone or brace treatment with a Pavlik harness for a minimum of 6 weeks. Follow-up visits will occur at 6 weeks, 1 year and 2 years post-enrolment. The primary outcome will be the norm-referenced acetabular index measured on the 2-year radiograph with a 3° non-inferiority margin. A total of 514 patients will be included.The study is anticipated to start in April 2024 and end in September 2028.The primary outcome will be compared between arms with a mixed-effects model with a random intercept for study centre, and a single covariate for the treatment group. If the lower bound of the 95% CI lies within 3° of the mean, we will treat this as evidence for non-inferiority.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from the lead site's ethics board (University of British Columbia, Children's and Women's Research Ethics Board). Ethics approval will be obtained from the local ethics committees or institutional review boards at each institution prior to patient enrolment. It is intended that the results of this study shall be published in peer-reviewed journals and presented at suitable conferences.

TRIAL REGISTRATION NUMBER

NCT05869851.

Acetabular index as an indicator of Pavlik harness success in grade I developmental dysplasia of the hip: A retrospective study

Purpose

Some articles have focused on the effectiveness of the Pavlik harness treatment for unstable and dislocated hips, yet data on monitoring its effectiveness with the acetabular index remains elusive. Therefore, this study aimed to assess Pavlik harness effectiveness in infants ≤6 months diagnosed with grade I developmental dysplasia of the hip using acetabular index improvement and identify the possible predictors of successful Pavlik harness treatment.

Methods

A retrospective review of infants with grade I acetabular dysplasia treated with a Pavlik harness and monitored with anteroposterior pelvis X-rays at presentation and follow-up. Successful treatment was defined as achieving an acetabular index <30°.

Results

A total of 231 infants with acetabular dysplasia were treated with a Pavlik harness. A successful outcome was achieved in 135 infants (58.4%). Younger age, lower initial acetabular index, and patients with unilateral developmental dysplasia of the hip were significant predictors of a successful outcome. An age of 4.5 months or older was found to be the threshold for an unsuccessful result following Pavlik harness treatment, with a sensitivity of 65.2% and specificity of 57.3%. An initial acetabular index of 35.5° was found to be the threshold for an unsuccessful result, with a sensitivity of 83.7% and specificity of 61.5%.

Conclusion

Pavlik Harness's success in correcting the acetabular index in acetabular dysplasia patients was related to unilateral cases, a younger age at presentation, and a lower initial acetabular index. The thresholds for unsuccessful treatment were an age of 4.5 months or greater and an acetabular index of 35.5° or higher.

Active monitoring versus an abduction device for treatment of infants with centered dysplastic hips: study protocol for a randomized controlled trial (TReatment with Active Monitoring (TRAM)-Trial)

BACKGROUND

Developmental Dysplasia of the Hip (DDH) is one of the most common pediatric orthopedic disorders, affecting 1-3% of all newborns. The optimal treatment of centered DDH is currently under debate. This randomized controlled trial aims to study the (cost-)effectiveness of active monitoring versus abduction treatment for infants with centered DDH.

METHODS

This is a multicenter, parallel-group, open-label, non-inferiority randomized controlled trial studying the (cost-)effectiveness of active monitoring versus abduction treatment for infants with centered DDH in fourteen hospitals in the Netherlands. In total, 800 infants with centered DDH (Graf IIa-/IIb/IIc), aged 10-16 weeks, will be randomly allocated to the active monitoring or abduction treatment group. Infants will be followed up until the age of 24 months. The primary outcome is the rate of normal hips, defined as an acetabular index lower than 25 degrees on an antero-posterior radiograph, at the age of 12 months. Secondary outcomes are the rate of normal hips at the age of 24 months, complications, time to hip normalization, the relation between baseline patient characteristics and the rate of normal hips, compliance, costs, cost-effectiveness, budget impact, health-related quality of life (HRQoL) of the infant, HRQoL of the parents/caregivers, and parent/caregiver satisfaction with the treatment protocol.

DISCUSSION

The outcomes of this randomized controlled trial will contribute to improving current care-as-usual for infants with centered DDH.

TRIAL REGISTRATION

Dutch Trial Register, NL9714, registered September 6, 2021. https://clinicaltrialregister.nl/en/trial/29596.

Intra- and interobserver variability of novel magnetic resonance imaging parameters for hip screening and treatment outcomes at age 5 years

BACKGROUND

The outcome measure of neonatal hip screening is usually the radiographic acetabular index.

OBJECTIVE

To assess the feasibility of magnetic resonance imaging (MRI) without sedation and compare the utility of outcome parameters measured from MRI images.

MATERIALS AND METHODS

The invitation for MRI scanning at 5 years of age was incorporated into follow-up for babies who had more than one ultrasound examination during treatment or surveillance.

RESULTS

Diagnostic images were obtained in 132 of 134 children. The mean osseous acetabular index (standard deviation [SD]) was 16.6 (3.3) degrees for the right hip and 17.8 (3.2) for the left; the values for the cartilaginous acetabular index were 3.1 (3) and 3.4 (3.2). The mean downslope of a tangent to the lateral bony acetabular roof was 10.4 (4.5) and 9.0 (4.3) with respect to Hilgenreiner's line and that of a line drawn through the apex to the margin of the acetabulum was 3.7 (4.6) and 3.9 (4.7). Intra- and interobserver variation was greater for measures specific to the lateral acetabular roof than for ossific and cartilaginous indices. There was significant negative correlation between the downslope of the tangent to the lateral roof index and the age at onset of treatment on both sides, but no significant correlation for ossific or cartilaginous acetabular indices or apex-marginal index.

CONCLUSION

MRI without sedation at 5 years of age is feasible as an outcome measure for hip screening programmes. Parameters specific to the lateral acetabulum may better reflect acetabular sufficiency, despite having greater observer variation than cartilaginous and ossific acetabular indices.

Universal screening may reduce the incidence of late diagnosis of developmental dysplasia of the hip : a systematic review and meta-analysis

AIMS

We investigated the prevalence of late developmental dysplasia of the hip (DDH), abduction bracing treatment, and surgical procedures performed following the implementation of universal ultrasound screening versus selective ultrasound screening programmes.

METHODS

A systematic search of PubMed, Embase, The Cochrane Library, OrthoSearch, and Web of Science from the date of inception of each database until 27 March 2022 was performed. The primary outcome of interest was the prevalence of late detection of DDH, diagnosed after three months. Secondary outcomes of interest were the prevalence of abduction bracing treatment and surgical procedures performed in childhood for dysplasia. Only studies describing the primary outcome of interest were included.

RESULTS

A total of 31 studies were identified, of which 13 described universal screening and 20 described selective screening. Two studies described both. The prevalence of late DDH was 0.10 per 1,000 live births (95% confidence interval (CI) 0.00 to 0.39) in the universal screening group and 0.45 per 1,000 live births (95% CI 0.31 to 0.61) in the selective screening group. Abduction bracing treatment was performed on 55.54 per 1,000 live births (95% CI 24.46 to 98.15) in the universal screening group versus 0.48 per 1,000 live births (95% CI 0.07 to 1.13) in the selective screening group. Both the universal and selective screening groups had a similar prevalence of surgical procedures in childhood for dysplasia being performed (0.48 (95% CI 0.32 to 0.63) vs 0.49 (95% CI 0.31 to 0.71) per 1,000 live births, respectively).

CONCLUSION

Universal screening showed a trend towards lower prevalence of late DDH compared to selective screening. However, it was also associated with a significant increase in the prevalence of abduction bracing without a significant reduction in the prevalence of surgical procedures in childhood for dysplasia being performed. High-quality studies comparing both treatment methods are required, in addition to studies into the natural history of missed DDH.Cite this article: Bone Joint J 2023;105-B(2):198-208.

Application of Accepted Use Criteria for the Treatment of Developmental Dysplasia of the Hip Decreases the Number of Infants Treated With a Pavlik Harness

BACKGROUND

This analysis examined how the application of the American Academy of Orthopedic Surgeons appropriate use criteria (AUC) for developmental dysplasia of the hip in infants would change treatment patterns and outcomes for Graf IIA hips at a single quaternary pediatric hospital.

METHODS

After Institutional Review Board approval, patient medical records were reviewed and data were collected. Graf IIa hips were defined as alpha angle (AA) 50 to 59 degrees. AA and femoral head coverage (FHC) were measured from initial and 6-month ultrasounds and acetabular index (AI) was measured from radiographs at 6 months of age. Instability (positive Ortolani and Barlow tests) was noted. On the basis of the American Academy of Orthopedic Surgeons AUC for managing developmental dysplasia of the hip, hips were further categorized as normal (FHC ≥45%), borderline (FHC 35% to 44%), or dysplastic (FHC <35%).

RESULTS

Overall, 13% (49/371) of Graf IIa hips (AA 50 to 59 degrees) were dysplastic (FHC <35%). Total 24% (89/371) were clinically unstable. Total 42% (37/89) of unstable Graf IIa hips were dysplastic. Only 4% of stable Graf IIa hips were dysplastic (12/282). Out of 371 Graf IIa hips, 256 were treated with Pavlik harness (n=250) or Rhino brace (n=6). Among stable, nondysplastic (SND) hips (those with normal and borderline FHC≥35%), 33% (52/158) were treated because of a more severe contralateral side. If the AUC had been applied, 67% (106/158) of SND Graf IIa hips would not have been treated. Among the n=162 hips that returned for a 6-month radiograph, there was no difference in AI in the 115 treated and 47 untreated SND hips (mean difference treatment vs. no treatment: -1.5, 95% CI, -3.1 to 0.2, P =0.0808).

CONCLUSIONS

Using AUC recommendations, our center could reduce the number of SND Graf IIa hips we treat by 67%. Although 24% of Graf IIa hips were clinically unstable and 13% were dysplastic based on FHC, most Graf IIa hips had normal or borderline FHC per the AUC and may do well with observation and follow-up ultrasound at 12 weeks old.

LEVEL OF EVIDENCE

Level III-diagnostic study.

The management of developmental dysplasia of the hip in children aged under three months : a consensus study from the British Society for Children's Orthopaedic Surgery

AIMS

A national screening programme has existed in the UK for the diagnosis of developmental dysplasia of the hip (DDH) since 1969. However, every aspect of screening and treatment remains controversial. Screening programmes throughout the world vary enormously, and in the UK there is significant variation in screening practice and treatment pathways. We report the results of an attempt by the British Society for Children's Orthopaedic Surgery (BSCOS) to identify a nationwide consensus for the management of DDH in order to unify treatment and suggest an approach for screening.

METHODS

A Delphi consensus study was performed among the membership of BSCOS. Statements were generated by a steering group regarding aspects of the management of DDH in children aged under three months, namely screening and surveillance (15 questions), the technique of ultrasound scanning (eight questions), the initiation of treatment (19 questions), care during treatment with a splint (ten questions), and on quality, governance, and research (eight questions). A two-round Delphi process was used and a consensus document was produced at the final meeting of the steering group.

RESULTS

A total of 60 statements were graded by 128 clinicians in the first round and 132 in the second round. Consensus was reached on 30 out of 60 statements in the first round and an additional 12 in the seond. This was summarized in a consensus statement and distilled into a flowchart to guide clinical practice.

CONCLUSION

We identified agreement in an area of medicine that has a long history of controversy and varied practice. None of the areas of consensus are based on high-quality evidence. This document is thus a framework to guide clinical practice and on which high-quality clinical trials can be developed.Cite this article: Bone Joint J 2023;105-B(2):209-214.

Clinical and sonographic improvement of developmental dysplasia of the hip: analysis of 948 patients

BACKGROUND

Developmental dysplasia of the hip is a common condition, which varies in severity. Abduction treatment is widely used to correct the development of the hips, but mild forms of DDH can also recover spontaneously. The purpose of this study was to evaluate factors affecting the rate of improvement of developmental dysplasia of the hip, and evaluate any risk factors slowing the process.

MATERIAL AND METHODS

The study population consisted of patients diagnosed with DDH in Tampere University hospital in the years 1998-2018. Data were retrospectively collected, and associations between clinical variables and rate of improvement were analyzed. Alpha angles were assessed monthly, and associations between risk factors and improvement of alpha angles were studied. A total of 948 patients were included in the analysis.

RESULTS

More severe first status of the hips was associated with faster improvement in dynamic ultrasound compared to milder DDH in univariate design in first 3 months of age; in the multivariable design, Ortolani positivity was conversely associated with lower alpha angles in 1-month follow-up. Immediate abduction treatment was associated with faster recovery rate compared to delayed abduction or watchful waiting. Female sex and positive family history were associated with slower rate of improvement and lower alpha angles. In multivariable design, female sex, positive family history and treatment strategy remained statistically significant as initiation time of the treatment explained the first found association of clinical hip status and the recovery rate after 2 months of age.

CONCLUSION

Female sex and positive family history might be independent risk factors for slower recovery in DDH before 6 months of age. These children might need special attention in their follow-up plans and abduction treatment.

Splinting for the non-operative management of developmental dysplasia of the hip (DDH) in children under six months of age

BACKGROUND

Developmental dysplasia of the hip (DDH) describes the abnormal development of a hip in childhood, ranging from complete dislocation of the hip joint to subtle immaturity of a hip that is enlocated and stable within the socket. DDH occurs in around 10 per 1000 live births, though only one per 1000 are completely dislocated. There is variation in treatment pathways for DDH, which differs between hospitals and even between clinicians within the same hospital. The variation is related to the severity of dysplasia that is believed to require treatment, and the techniques used to treat dysplasia.

OBJECTIVES

To determine the effectiveness of splinting and the optimal treatment strategy for the non-operative management of DDH in babies under six months of age.

SEARCH METHODS

We searched CENTRAL, MEDLINE, Embase, seven other electronic databases, and two trials registers up to November 2021. We also checked reference lists, contacted study authors, and handsearched relevant meetings abstracts.

SELECTION CRITERIA

Randomised controlled trials (RCTs), including quasi-RCTs, as well as non-RCTs and cohort studies conducted after 1980 were included. Participants were babies with all severities of DDH who were under six months of age. Interventions included dynamic splints, static splints or double nappies (diapers), compared to no splinting or delayed splinting.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies, extracted data and performed risk of bias and GRADE assessments. The primary outcomes were: measurement of acetabular index at years one, two and five, as determined by radiographs (angle): the need for operative intervention to achieve reduction and to address dysplasia; and complications. We also investigated other outcomes highlighted by parents as important, including the bond between parent and child and the ability of mothers to breastfeed.

MAIN RESULTS

We included six RCTs or quasi-RCTs (576 babies). These were supported by 16 non-RCTs (8237 babies). Five studies had non-commercial funding, three studies stated 'no funding' and 14 studies did not state funding source. The RCTs were generally at unclear risk of bias, although we judged three RCTs to be at high risk of bias for incomplete outcome data. The non-RCTs were of moderate and critical risk of bias. We did not undertake meta-analysis due to methodological and clinical differences between studies; instead, we have summarised the results narratively. Dynamic splinting versus delayed or no splinting Four RCTs and nine non-RCTs compared immediate dynamic splinting and delayed dynamic splinting or no splinting. Of the RCTs, two considered stable hips and one considered unstable (dislocatable) hips and one jointly considered unstable and stable hips. No studies considered only dislocated hips. Two RCTs (265 babies, very low-certainty evidence) reported acetabular index at one year amongst stable or dislocatable hips. Both studies found there may be no evidence of a difference in splinting stable hips at first diagnosis compared to a strategy of active surveillance: one reported a mean difference (MD) of 0.10 (95% confidence interval (CI) -0.74 to 0.94), and the other an MD of 0.20 (95% CI -1.65 to 2.05). Two RCTs of stable hips (181 babies, very low-certainty evidence) reported there may be no evidence of a difference between groups for acetabular index at two years: one study reported an MD of -1.90 (95% CI -4.76 to 0.96), and another study reported an MD of -0.10 (95% CI -1.93 to 1.73), but did not take into account hips from the same child. No study reported data at five years. Four RCTs (434 babies, very low-certainty evidence) reported the need for surgical intervention. Three studies reported that no surgical interventions occurred. In the remaining study, two babies in the dynamic splinting group developed instability and were subsequently treated surgically. This study did not explicitly state if this treatment was to achieve concentric reduction or address residual dysplasia. Three RCTs (390 babies, very low-certainty evidence) reported no complications (avascular necrosis and femoral nerve palsy). Dynamic splinting versus static splinting One RCT and five non-RCTs compared dynamic versus static splinting. The RCT (118 hips) reported no occurrences of avascular necrosis (very low-certainty evidence) and did not report radiological outcomes or need for operative intervention. One quasi-RCT compared double nappies versus delayed or no splinting but reported no outcomes of interest. Other comparisons No RCTs compared static splinting versus delayed or no splinting or staged weaning versus immediate removal.

AUTHORS' CONCLUSIONS

There is a paucity of RCT evidence for splinting for the non-operative management of DDH: we included only six RCTs with 576 babies. Moreover, there was considerable heterogeneity between the studies, precluding meta-analysis. We judged the RCT evidence for all primary outcomes as being of very low certainty, meaning we are very uncertain about the true effects. Results from individual studies provide limited evidence of intervention effects on different severities of DDH. Amongst stable dysplastic hips, there was no evidence to suggest that treatment at any stage expedited the development of the acetabulum. For dislocatable hips, a delay in treatment onset to six weeks does not appear to result in any evidence of a difference in the development of the acetabulum at one year or increased risk of surgery. However, delayed splinting may reduce the number of babies requiring treatment with a harness. No RCTs compared static splinting with delayed or no splinting, staged weaning versus immediate removal or double nappies versus delayed or no splinting. There were few operative interventions or complications amongst the RCTs and the non-randomised studies. There's no apparent signal to indicate a higher frequency of either outcome in either intervention group. Given the frequency of this disease, and the fact that many countries undertake mandatory DDH screening, there is a clear need to develop an evidence-based pathway for treatment. Particular uncertainties requiring future research are the effectiveness of splinting amongst stable dysplastic hips, the optimal timing for the onset of splinting, the optimal type of splint to use and the need for 'weaning of splints'. Only once a robust pathway for treatment is established, can we properly assess the cost-effectiveness of screening interventions for DDH.

Active monitoring versus immediate abduction as treatment of stable developmental dysplasia of the hip: a systematic review of the literature

OBJECTIVES

This systematic review aims to compare the effects of active monitoring and abduction treatment on the Graf alpha angle, Acetabular Index (AI) and femoral head coverage in infants with stable developmental dysplasia of the hip (DDH).

DESIGN

Systematic review reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

DATA SOURCES

A search of the PubMed, Embase, Cochrane and Web of Science databases was performed in January 2020 and updated in January 2021.

ELIGIBILITY CRITERIA

(Non-)randomised studies comparing active monitoring with abduction treatment in infants younger than 4 months with stable DDH were included.

DATA EXTRACTION AND SYNTHESIS

All eligible articles were methodologically assessed using the Cochrane risk of bias tools. Data were extracted by summarising the study characteristics and results.

RESULTS

Of the six included studies, two randomised studies were of low risk and two of some concerns. Two non-randomised studies were of serious risk. In total, 544 dysplastic hips (439 infants) were investigated, of which 307 were observed and 237 were treated. Two studies reported a faster improvement of the alpha angle and average acetabular coverage in treated hips at 3 months. No differences in AI between the treatment and observation group after 3 months were reported. In total, 38 infants (12%) in the observation group switched to the treatment group. At the final radiograph, 21 observed hips and 32 treated hips were dysplastic.

CONCLUSIONS

There were no differences in AI between the treatment and observation group after 3 months in infants up to 4 months of age with stable DDH hips. The switch of 38 infants (12%) from the observation to the treatment group corroborates that not all infantile DDH hips will spontaneously progress into normal hips. The small study population sizes and methodological heterogeneity warrant a large randomised controlled trial to study this research question.

PROSPERO REGISTRATION NUMBER

CRD4202123300.

Statistical Shape Modeling of US Images to Predict Hip Dysplasia Development in Infants

Background The current widely applied Graf classification used on US images for developmental dysplasia of the hip in infants does not enable prediction of the development and outcome of well-centered stable dysplastic hips (Graf type II). Purpose To use statistical shape modeling on US images to identify acetabular shape characteristics of Graf type II hips, which enable prediction of the development of Graf type II hips, and to identify which hips benefit from Pavlik harness treatment. Materials and Methods In this secondary analysis of a prospective multicenter randomized trial on treatment of 104 infants aged 3-4 months with Graf type IIb or IIc hip dysplasia conducted between 2009 and 2015, a statistical shape model was developed on baseline US images. With multivariable logistic regression adjusted for infant sex and treatment (Pavlik harness treatment vs active observation), shape modes were correlated with the outcomes of persistent hip dysplasia on US images (α angle <60°) after 12-week follow-up and residual hip dysplasia on pelvic radiographs (Tönnis classification: acetabular index greater than 2 standard deviations) around 1 year of age. An interaction term (treatment with mode) was used to investigate if this result depended on treatment. Results Baseline US images were available in 97 infants (mean age, 3.37 years ± 0.43 [standard deviation]; 89 [92%] girls; 90 cases of Graf type IIb hip dysplasia; 52 cases treated with Pavlik harness). Shape modes 2 and 3 of the statistical shape modeling were associated with persistent hip dysplasia on US images (odds ratio [OR] = 0.43; P = .007 and OR = 2.39; P = .02, respectively). Mode 2 was also associated with residual hip dysplasia on pelvic radiographs (OR = 0.09; P = .002). The interaction term remained significant after multivariable analysis, indicating that Pavlik harness treatment was beneficial in patients with negative mode 2 values (OR = 12.46; P = .01). Conclusion Statistical shape modeling of US images of infants with Graf type II dysplastic hips predicted which hips developed to normal or remained dysplastic and identified hips that benefited from Pavlik harness treatment. © RSNA, 2022.

Principles of Bracing in the Early Management of Developmental Dysplasia of the Hip

Bracing is considered a gold standard in treating Developmental Dysplasia of the Hip (DDH) in infants under 6 months of age with reducible hips. A variety of braces are available that work on similar principles of limiting hip adduction and extension. This paper summarises the current evidence regarding bracing in DDH. Most of the literature pertains to the Pavlik harness (PH) and there are few studies for other brace types. Bracing eliminates dislocating forces from the hamstrings, the block to reduction of the psoas and improves the muscle line of pull to stabilise the hip joint. Recent studies have shown no benefit in bracing for stable dysplasia. The rates of PH treatment failure in Ortolani-positive hips have been reported to be high. Barlow positive hips have lower Graf grades and are more amenable to PH treatment. There is consensus that the earlier the diagnosis of DDH and initiation of PH treatment, the better the outcome. Failure rates due to unsuccessful reduction and AVN are higher with treatment initiated after age 4-6 months. Studies have shown no benefits of staged weaning of braces. While there is no maximum time in brace, current consensus suggests a minimum of 6 weeks. The key to successful bracing lies in education and communication with the family.

Examining the Short-Term Natural History of Developmental Dysplasia of the Hip in Infancy: A Systematic Review

BACKGROUND

This study was an update on the AAOS clinical practice guideline's analysis of the natural history of developmental dysplasia of the hip (DDH). The objective was to delineate the natural history of clinical instability or radiologic abnormalities of the hip in infants by identifying the proportion of cases that resolved without treatment compared to cases that progressed and/or required treatment.

METHODS

We performed a literature search of PUBMED to identify studies which evaluated the natural history of DDH. We used the same search strategy as that utilized in the previous AAOS guidelines, updated to include articles published between September 2013 and May 2021. We assessed the quality of included articles using the Oxford Centre for Evidence-Based Medicine level of evidence and reported study demographics and outcomes using summary statistics.

RESULTS

Twenty-four articles met our eligibility criteria. Most included studies were retrospective (14/24), investigated either the incidence of DDH (8/24) or assessed screening programs (7/24). The most prevalent study population followed were Graf 2A hips (7/24). Most studies were low quality with level of evidence 3 (13/24) or 4 (7/24). Sample sizes ranged from 9 to 3251. Twenty studies reported the number of cases resolved over the follow-up period with a mean rate of 84.3% (95% confidence interval 76.1, 92.6).

CONCLUSION

We found most mild-to-moderate DDH can resolve without treatment in early infancy, especially in physiologically immature (Graf 2A) hips. More high-quality evidence is needed to properly assess the natural history of DDH as only one included study was a randomized trial.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s43465-021-00510-6.

Timing of Repeat Ultrasound Examination in Treatment of Stable Developmental Dysplasia of the Hip

BACKGROUND

Worldwide a wide variation exists in duration of Pavlik harness treatment for infants up to 6 months with stable developmental dysplasia of the hip (DDH). The purpose of this study was to evaluate whether shortening the time to first routine follow-up ultrasound after initiation of Pavlik harness treatment would reduce treatment duration and whether this influenced radiologic outcome at 1 year of age. Furthermore, predictors of higher acetabular index (AI) at 1 year of age were investigated.

METHODS

A retrospective study was conducted in infants with stable DDH (Graf IIb and IIc) diagnosed and treated between 2015 and 2017. Two groups were identified: first routine follow-up ultrasound at 12 weeks after Pavlik harness initiation (group I) and first routine follow-up ultrasound at 6 weeks after Pavlik harness initiation (group II). In both groups, treatment was continued until repeat ultrasound measurements (every 6 wk) showed a normalized hip. Radiologic outcome at 1 year of age was defined as residual dysplasia measured on an anteroposterior hip radiograph according to the Tönnis table.

RESULTS

A total of 222 infants were included. The median time of Pavlik harness treatment was 12 weeks (interquartile range, 11.9 to 12.3) in group I compared with 6.1 weeks (interquartile range, 6.0 to 7.5) in group II (P<0.001). Residual dysplasia at 1 year of age was detected in 20 infants (16.8%) in group I compared with 11 infants (10.7%) in group II (P=0.189). The multivariable prediction model showed that positive family history and lower baseline alpha angle correlate with a higher AI at 1 year of age.

CONCLUSIONS

First routine follow-up ultrasound can be safely brought forward from 12 to 6 weeks after Pavlik harness initiation. Furthermore, infants with a positive family history for DDH and an initial low alpha angle are at higher risk to have a higher AI at 1 year of age.

LEVEL OF EVIDENCE

Level III-retrospective study.