Screening for developmental dysplasia of the hip: a systematic literature review for the US Preventive Services Task Force

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.

The Risk of Developmental Dysplasia of the Hip in Premature Infants with Breech Presentation at Birth

OBJECTIVE

This article evaluates the risk (defined here as incidence per 1,000 infants) of developmental dysplasia of the hip (DDH) in premature infants undergoing hip ultrasound (HUS) for breech presentation only compared with other indications.

STUDY DESIGN

Retrospective study of infants born between January 1, 2009 and December 31, 2018 at <37 weeks' gestation with a HUS obtained in the first year of life, at Nationwide Children's Hospital, the only available facility for pediatric radiology and orthopaedic services in central Ohio. We calculated risk differences and odds ratios of DDH by the indication of HUS.

RESULTS

From 2,397 infants reviewed, 89% underwent HUS for breech presentation only. The local incidence of DDH for infants undergoing HUS for breech-only indication was 15 per 1,000 compared with 155 per 1,000 for infants undergoing HUS for other indications. The odds ratio of DDH diagnosis was 12.1 (95% confidence interval: 7.5, 19.6) for infants undergoing HUS for an indication other than breech presentation only relative to infants undergoing HUS for the indication of breech presentation only.

CONCLUSION

The risk of DDH diagnosis in premature infants undergoing HUS for breech presentation is much lower than those undergoing HUS for clinical concerns and other risk factors. Screening these infants with physical examination may be sufficient.

KEY POINTS

· Breech presentation is the most common indication for hip ultrasound in premature infants.. · The risk of DDH is lower in premature infants with breech presentation compared with premature infants with other clinical concerns.. · The risk of DDH is higher in infants born at 33 to 36 weeks of gestation compared with those born at an earlier gestation..

[Pediatric Hip Disorders]

Developmental dysplasia of the hip is a condition characterized by hip joint instability due to acetabular dysplasia in infancy, necessitating precise ultrasound examination. Legg-Calvé-Perthes disease is caused by a temporary disruption in blood flow to the femoral head during childhood, progressing through avascular, fragmentation, re-ossification, and residual stages. Slipped capital femoral epiphysis is a condition where the femoral head shifts medially along the epiphyseal line during adolescence due to stress, such as weight-bearing. Differentiating between transient hip synovitis and septic arthritis may require joint fluid aspiration. Osteomyelitis can be associated with soft tissue edema and osteolysis. When multiple lesions are present, it is essential to distinguish between Langerhans cell histiocytosis and metastatic neuroblastoma. This review will introduce imaging techniques and typical findings for these conditions.

Comparison of quality and interpretation of newborn ultrasound screening examinations for developmental dysplasia of the hip by basically trained nurses and junior physicians with no previous ultrasound experience

BACKGROUND

We are obliged to give babies the chance to profit from a nationwide screening of developmental dysplasia of the hip in very rural areas of Mongolia, where trained physicians are scarce. This study aimed to compare the quality and interpretation of hip ultrasound screening examinations performed by nurses and junior physicians.

METHODS

A group of 6 nurses and 6 junior physician volunteers with no previous ultrasound experience underwent Graf's standard training in hands-on practice. Newborns were examined before discharge from the hospital, according to the national guideline. Two standard documentation images of each hip were saved digitally. The groups were compared on the proportion of good quality of sonograms and correct interpretation. Two Swiss supervisors' agreed diagnosis according to Graf was considered the final reference for the study purposes.

RESULTS

A total of 201 newborns (402 hips or 804 sonograms) were examined in the study, with a mean age of 1.3±0.8 days at examination. Junior physicians examined 100 newborns (200 hips or 400 sonograms), while nurses examined 101 newborns (202 hips or 404 sonograms). The study subjects of the two groups were well balanced for the distribution of baseline characteristics. The study observed no statistically significant difference in the quality of Graf's standard plane images between the providers. Eventually, 92.0% (92) of the physician group and 89.1% (90) of the nurse group were correctly diagnosed as "Group A" (Graf's Type 1 hip) or "Non-Group A" hips (p = 0.484). The most common errors among the groups were a missing lower limb, wrong measurement lines, and technical problems.

CONCLUSION

Our study provides evidence that while there might be a trend of slightly more technical mistakes in the nurse group, the overall diagnosis accuracy is similar to junior physicians after receiving standard training in Graf's hip ultrasound method. However, after basic training, regular quality control is a must and all participants should receive refresher trainings. More specifically, nurses need training in the identification of anatomical structures.

Neonatal Ultrasound and Radiographic Markers of Hip Dysplasia in Young Adults

OBJECTIVES

To examine radiologic outcomes at skeletal maturity of sonographically normal, immature, mildly, and severely dysplastic newborn hips.

METHODS

During 1988 to 1990, 11 925 newborns were enrolled in a randomized controlled trial examining screening strategies for developmental hip dysplasia. In total, 4469 were invited to clinical and radiologic follow-up 18 years later, of which 1735 had received neonatal ultrasound. Radiographic markers for dysplasia in left adult hips included the center-edge (CE) angle.

RESULTS

At follow-up, 984 of 1735 (56.7%) with newborn ultrasound met, of which 966 (614 females) had valid radiographs and were thus included. For females, 34 (10.2%) and 1 (0.3%) of the 332 sonographically normal left neonatal hips were judged borderline (20°≤ CE <25°) or dysplastic (CE <20°) at skeletal maturity respectively. Corresponding numbers were 36 (19.7%) and 3 (1.6%) of the 183 immature, 12 (15.6%) and 2 (2.6%) of the 77 mildly dysplastic, and 3 (13.6%) and 3 (13.6%) of the 22 severely dysplastic neonatal left hips (P ≤ .001). In males, no associations were found. In females, adult joint hypermobility was associated with sonographic neonatal hip instability (P = .046), as well as with adult acetabular dysplasia (P = .024).

CONCLUSIONS

Significant associations between neonatal hip phenotypes and adult dysplasia were revealed in females. This indicates the possibility of different mechanisms affecting the course of developmental dysplasia of the hip for females and males, prompting consideration of prolonged clinical and radiologic follow-up for females with dysplastic neonatal hips. Results in males are limited by low numbers of dysplastic hips. The significance of joint hypermobility warrants further investigation.

Incidence, Prevalence, Risk Factors, and Clinical Treatment for Children with Developmental Dysplasia of the Hip in Saudi Arabia. A Systematic Review

BACKGROUND

Developmental dysplasia of the hip (DDH) leads to pain, joint instability, and early degenerative joint disease. Incidence, prevalence, and management strategies of DDH have been well-documented in several countries, but not in Saudi Arabia.

OBJECTIVE

We synthesized the current evidence regarding incidence, prevalence, risk factors, and clinical treatment for children with DDH in Saudi Arabia.

METHODS

We searched 3 databases to locate studies. Studies that included children with DDH in Saudi Arabia; reported either incidence rate, prevalence, risk factors, and/or clinical practice; and were available in English or Arabic were included. We excluded reviews, case studies, or animal studies. Two independent authors reviewed potential studies and assessed study's quality.

RESULTS

Our search yielded 67 potential studies, of which 16 studies were included (total DDH sample = 3,127; age range = 2.5 to 86.4 months). Three studies reported incidence rates ranging from 3.1 to 4.9 per 1000 births, and 3 studies reported prevalence ranging from 6 to 78%. Nine studies reported that female sex, breech position, family history, and age less than 3 years were risk factors associated with DDH. Four studies reported that brace applications and closed reduction were conservative treatments, and 9 studies reported that open hip reduction, adductor tenotomy, and/or pelvic osteotomy were surgical approaches to treat DDH.

CONCLUSIONS

In Saudi Arabia, the Incidence and prevalence rates of DDH are 3.1 to 4.9 per 1,000 births, and 6-78%, respectively (differ from what has been reported in other countries), but the risk factors of DDH in Saudi Arabia appear to be similar in comparison to other countries (female, breech presentation, family history of DDH).

Nurses assessment of development hip dysplasia: A scoping review

Developmental hip dysplasia is an abnormality of the hip joint which is associated with an unstable or dislocatable hip. During infancy, hips should be screened to determine whether they are stable, unstable or dislocated. In Australia, this screening is often performed by nurses using physical assessment. Physical examination includes a number of assessments which seek to identify underlying abnormalities in hip joint anatomy and function. This scoping review outlines the physical assessments used by nurses in the screening and surveillance of developmental hip dysplasia. A review of the literature identified 15 (N = 15; 100%) sources of evidence, which included original research articles (n = 6; 40%), expert opinion pieces (n = 2; 13.3%) and practice guidelines (n = 7; 46.7%). There were 18 physical assessments identified as being used by nurses in the screening process for developmental hip dysplasia. However, it is apparent that high quality research is required to examine the timing, specificity and sensitivity of the physical assessments identified.

Reapplication of the Pavlik Harness for Treatment of Developmental Dysplasia of the Hip After Initial Pavlik Harness Failure

OBJECTIVE

The Pavlik harness (PH) has been widely used as the standard treatment for infants with developmental dysplasia of the hip (DDH). When the initial application of the PH fails, alternative treatments, such as closed reduction, open reduction, and reapplication of the PH will be considered. Compared with other treatments, reapplication of the PH offers certain advantages, including simplicity and reduced physical, and psychological stress, on both infants and caregivers. This study aims to investigate the effectiveness of reapplying the PH in patients with DDH.

METHODS

This study included patients with DDH (complete dislocation) who were treated by reapplication of PH between 1988 and 2012. Patients who were able to follow-up for more than 5 years were included. We examined the reduction rate and several factors to identify indicators associated with successful reduction during reapplication, including age, sex, side of hip dislocation, and the presence of the Ortolani sign. At the final follow-up, hip development was assessed using the Severin classification, whereas avascular necrosis (AVN) was evaluated using the Kalamchi classification and the Salter criteria.

RESULTS

A total of 56 patients (48 females and 8 males) and 57 hips were included in this study. The mean age at first and second application of PH was 4.2 months old (range: 0.12 to 6.4), and 5.8 months old (3.0 to 11.4), respectively. The reduction rate was 49% (28 out of 57 hips). Among the successfully reduced hips, the AVN rate was 3.6% (1 out of 28 hips). The Severin classification revealed 27 hips in class I and 1 hip in class III. Statistical analysis indicated a significantly higher proportion of left hip involvement in the reduction group (85% vs 41%, χ 2 test, P < 0.001). Although not statistically significant, the rate of positive Ortolani sign tended to be higher in the reduction group (61% vs 38%, χ 2 test, P = 0.06).

CONCLUSION

The reapplication method demonstrated a 49% reduction rate and a low AVN rate of 3.6% in our study. It is worth considering for patients who fail the initial PH treatment, particularly in cases of left-side dislocation and a positive Ortolani sign during the initial application.

The effect of selective ultrasound screening on the incidence of late presentation of developmental hip dysplasia-a meta-analysis

Different screening strategies for developmental dysplasia of the hip (DDH) exist. Despite screening efforts, cases of late presentation continue to occur, often necessitating surgery. This systematic review and meta-analysis assess the effect of newborn selective ultrasound screening for DDH on the incidence of late presentation in infants and children, compared to a universal ultrasound strategy. A systematic search across Medline and EMBASE databases was performed between January 1950 and February 2021. A consensus-based evaluation of abstracts led to retrieval of relevant full text, original articles or systematic reviews in English only. These were assessed according to agreed eligibility criteria, and their reference lists were reviewed to identify additional eligible publications. Following final consensus on included publications, data was extracted, analysed and reported as per PRISMA and Prospero (CRD42021241957) guidelines. The 16 eligible studies consisted of 2 randomised controlled trials and 14 cohort studies, published between 1989 and 2014, with a total of 511,403 participants. In total, 121,470 (23.8%) received a neonatal hip ultrasound, of whom 58,086 and 63,384 were part of a selective or a universal ultrasound screening strategy, respectively. The difference in the proportion of late presentation between the universal and selective strategies was 0.0904 per 1,000 (P = 0.047). The time effect, i.e. the difference between early and late presentation defined respectively, as less than and more than 3 months of age, regardless of screening strategy, was not significant (P = 0.272). Although there was variability in study design and reporting, the quality of the evidence, based on the critical appraisal skills programme appraisal tools, was generally good. Compared to universal ultrasound screening for DDH, selective screening resulted in a slightly higher rate of late presentation. Uniformity in design and reporting of DDH studies and a cost-effectiveness analysis are needed.

Preterm birth does not increase the risk of developmental dysplasia of the Hip: a systematic review and meta-analysis

BACKGROUND

The purpose of this systematic review was to appraise the literature on the association between preterm birth and developmental dysplasia of the hip (DDH).

METHODS

Medline, Embase, Scopus, and Web of Science databases were queried for all studies pertaining to DDH and preterm birth. Data were imported and analyzed in Revman5 and Comprehensive Meta-Analysis (CMA) for pooled prevalence estimation.

RESULTS

Fifteen studies were included in the final analysis. There were 759 newborns diagnosed with DDH in these studies. DDH was diagnosed in 2.0% [95%CI:1.1-3.5%] of the premature newborns. Pooled incidence rate of DDH was not statistically different between those groups (2.5%[0.9%-6.8%] vs. 0.7%[0.2%-2.5%] vs. 1.7%[0.6%-5.3%];Q = 2.363,p = 0.307).

CONCLUSIONS

In this systematic review and meta-analysis, we did not find preterm birth to be a significant risk factor for DDH. Data suggests that female sex and breech presentation are associated with DDH in preterm infants, but the data is scarce in the literature.

Analysis of the results of hip ultrasonography in 48 666 infants and efficacy studies of conservative treatment

PURPOSE

This study aimed to investigate the detection rate of developmental dysplasia of the hip (DDH) by ultrasound. To obtain the distribution characteristics of the different types (I-IV) and the role of ultrasound in the evaluation of infants with DDH (type IIc and above) receiving conservative treatment.

METHODS

A retrospective analysis was performed. The chi-square test was used for comparisons between count-data groups. Two-sided tests were used for all analyses. The results of ultrasound follow-up after conservative treatment are described.

RESULTS

Among the 48 666 infants examined, the detection rates were as follows: type I, 95.42%; IIa, 3.18%; IIb, 0.91%; IIc, 0.22%; D, 0.01%; III, 0.14%; and IV, 0.12%. There were 4456 hips with IIa and above, more left (54.65%) than right (45.35%) hips, and more females (82.60%) than males (17.40%). The detection rate of type IIa and above was 4.58%, and that of type IIb and above was 1.40%. After the treatment, the α value increased, and β value decreased. The cure rate of the less-than-42-days group was higher than that of the other groups.

CONCLUSION

The ultrasound detection rate of DDH is high. DDH was more likely to occur on the left side and in females. It is recommended that the infants should be treated within 42 days.

A Prospective, Multicenter Study of Developmental Dysplasia of the Hip: What Can Patients Expect After Open Reduction?

BACKGROUND

Although there are several predominantly single-center case series in the literature, relatively little prospectively collected data exist regarding the outcomes of open hip reduction (OR) for infantile developmental dysplasia of the hip (DDH). The purpose of this prospective, multi-center study was to determine the outcomes after OR in a diverse patient population.

METHODS

The prospectively collected database of an international multicenter study group was queried for all patients treated with OR for DDH. Minimum follow-up was 1 year. Proximal femoral growth disturbance (PFGD) was defined by consensus review using Salter's criteria. Persistent acetabular dysplasia was defined as an acetabular index >90th percentile for age. Statistical analyses were performed to compare preoperative and operative characteristics that predicted re-dislocation, PFGD, and residual acetabular dysplasia.

RESULTS

A cohort of 232 hips (195 patients) was identified; median age at OR was 19 months (interquartile range 13 to 28) and median follow-up length was 21 months (interquartile range 16 to 32). Re-dislocation occurred in 7% of hips (n=16/228). The majority (81%; n=13/16) occurred in the first year after initial OR. Excluding patients with repeat dislocation, 94.5% of hips were IHDI 1 at most recent follow-up. On the basis of strict radiographic review, some degree of PFGD was present in 44% of hips (n=101/230) at most recent follow-up. Seventy-eight hips (55%) demonstrated residual dysplasia compared with established normative data. Hips that had a pelvic osteotomy at index surgery had about half the rate of residual dysplasia (39%; n=32/82) versus those without a pelvic osteotomy with at least 2 years follow-up (78%; n=46/59).

CONCLUSIONS

In the largest prospective, multicenter study to date, OR for infantile DDH was associated with a 7% risk of re-dislocation, 44% risk of PFGD, and 55% risk of residual acetabular dysplasia at short term follow-up. The incidence of these adverse outcomes is higher than previous reports. Patients treated with concomitant pelvic osteotomy had lower rates of residual dysplasia. These prospectively collected, multicenter data provide better generalizable information to improve family education and appropriately set expectations.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Tönnis and the Novel IHDI Radiographic Classification Systems for the Developmental Dysplasia of The Hip (DDH): Evaluation of 406 hips with DDH

In this study, we aimed to compare the efficiency of Tönnis and the novel International Hip Dysplasia Institute (IHDI) in decision making and in presuming the outcomes in children who had undergone closed reduction and casting. 406 hips of 298 patients who had undergone closed reduction and spica casting were included in this retrospective study. All hips were classified according to Tönnis and IHDI systems. Bucholz-Ogden classification was used for avascular necrosis. The outcomes of patients for each classification system were compared, in terms of the presence of avascular necrosis, redislocations and secondary surgeries at the end of the follow-up period. 318 hips were evaluated as Tönnis grade 2 dysplasia. 24 had avascular necrosis, 9 had redislocations. 79 hips were evaluated as Tönnis grade 3 dysplasia. 18 had AVN, 7 had redislocations. 9 hips were evaluated as Tönnis grade 4 dysplasia 3 had AVN, 4 had redislocations. 203 patients were evaluated as IHDI grade 2 dysplasia. 7 had AVN, 7 had redislocations.185 patients were assessed as IHDI grade 3 dysplasia. 33 had AVN, 11 had redislocations. 18 patients were evaluated as IHDI grade 4 dysplasia. 5 had AVN, 6 had redislocations. Both Tönnis classification and IHDI classification systems are reliable and efficient systems for evaluating the severity and predicting the success of closed reduction and casting for the treatment of DDH. IHDI classification has certain benefits, such as being a practical classification and a better distribution within the groups.

Radiographic markers of hip dysplasia in young adults: predictive effect of factors in early life

ABSTRAC

BACKGROUND AND OBJECTIVES: Acetabular dysplasia in young adults occurs, despite screening for developmental hip dysplasia (DDH) in the neonatal period. We aimed to examine how early life factors predict radiographic measurements of acetabular dysplasia at 18-19 years of age.

METHODS

From a previous randomized trial (n = 12,014; 1988-90) evaluating the role of hip ultrasound in newborn screening of DDH, 4469 participants (2193 males) were invited to a follow-up 18 years later (2007-09), of which 2370 (53% attendance; 932 males) met. We examined associations between early life factors and four radiographic measurements for acetabular dysplasia at skeletal maturity. Hierarchical regressions, with addition of variables observed/measured consecutively in time, were analyzed using mixed effects models considering hip as the unit in the analyses. The study is approved by the Regional Ethics Committee.

RESULTS

In total, 2340 participants (921 boys), mean age 18.7 years, (SD 0.6) had hip radiographs performed at follow-up and were included. Early life factors significantly predicting radiographic acetabular dysplasia at age 18-19-years included female gender, breech, low acetabular inclination (alpha) angle and sonographic instability, abduction treatment, as well as the velocity of growth during childhood. A positive family history of DDH was not associated with acetabular dysplasia at skeletal maturity.

CONCLUSION

The acetabular inclination (alpha) angle as measured on ultrasound at birth turned out to be a significant predictor of dysplasia at 18-19 years of age. The discordant role of a positive family history in early versus adult hip dysplasia is intriguing, warranting further studies on the genetic mechanisms of DDH.

Surgical procedures in infants with early diagnoses of developmental dysplasia of the hip. A prospective 4-year follow-up study

Background

Dysplastic hips infants may normalize spontaneously without any intervention due to the natural growth. However, some infants need one or more surgical interventions to achieve stable and non-dysplastic hips. The purpose of this study is to determine the proportion of infants diagnosed with DDH before the age of 6 months undergoing surgical procedures of the hip(s) before the age of four years and to determine the number and types of surgical procedures in each infant.

Methods

A prospective and consecutive study of all infants aged 0-6 months diagnosed with dysplasia of the hips in the combined paediatric orthopaedic and radiologic examination in the Region of Southern Denmark 2013-2017. From medical records, we obtained information about all surgical procedures in the hips including open or closed reductions, arthrographies, tenotomies, and pelvic osteotomies before the age of 4 years.

Results

Overall, 281 infants with hip dysplasia were included. The median age at first examination was 48 days. In 254 (90%) of the infants, the hips resolved spontaneously, and 27 (10%) needed one or more surgical interventions. Overall, the 27 infants had 47 surgical intervention as 12 infants had more than one intervention. One infants had five surgical interventions. The most frequent surgical procedures were closed reduction and arthrography with or without adductor tenotomy (58%) and pelvic osteotomy (27%). Among infants with surgical interventions, 23 (8.2%) had unstable hips, and four (1.4%) had stable hips. All four infants with stable hips had an arthrography and none required a pelvic osteotomy.

Discussion

This study supports the propensity for spontaneous normalization early dysplasia of the hips in infants. Only a small proportion of the infants needed surgical interventions to achieve stable and non-dysplastic hips.

Children's Hip Predictive (CHiP) Score: A Triage Tool for Hip Dislocation in Children Referred With Suspected Hip Dysplasia

BACKGROUND

A fundamental tenent of treating developmental dysplasia of the hip is to identify patients with dislocated hips early so as to avoid the long-term sequelae of late diagnosis. The aim of this study was to develop a readily useable triage tool for patients with suspected hip dislocation, based on the clinical history and examination findings of the referring practitioner.

METHODS

All primary care referrals (n=934) over a 3-year period for suspected developmental dysplasia of the hip to a tertiary pediatric center were evaluated. Defined parameters with respect to history and clinical examination were evaluated. Multivariable logistic regression was used to establish predictors of hip dislocation, and from this a predictive model was derived which incorporated significant predictors of dislocation. An illustrative nomogram translated this predictive model into a usable numerical scoring system called the Children's Hip Prediction score, which estimates probability of hip dislocation.

RESULTS

There were 97 dislocated hips in 85 patients. The final predictive model included age, sex, family history, breech, gait concerns, decreased abduction, leg length discrepancy, and medical/neurological syndrome. The area under receiver operating curve for the model is 0.761. A Children's Hip Prediction score of≥5 corresponds to a sensitivity of 76.3% and a score of≥15 has a specificity of 97.8%, corresponding to an odds ratio of 27.3 for increased risk of dislocation.

CONCLUSION

We found that a novel clinical prediction score, based on readily available history and examination parameters strongly predicted risk of dislocations in hip dysplasia referral. It is hoped that this tool could be utilized to optimize resource allocation and may be of particular benefit in less well-resourced health care systems.

LEVEL OF EVIDENCE

Level II.

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.

Risk factors for re-dislocation after closed reduction in children with developmental dysplasia of the hip

OBJECTIVE

To investigate the risk factors for re-dislocation after the closed reduction in children with developmental dysplasia of the hip (DDH).

METHODS

The clinical data of 88 children aged ≤ 18 months with DDH (103 hips) who were treated with adductor muscle relaxation + closed reduction + plaster fixation at the Children's Hospital, Zhejiang University School of Medicine from January 2015 to December 2017, were retrospectively analyzed. According to the diagnostic criteria of hip dislocation, patients were divided into two groups: reduction group and re-dislocation group. The univariate and multivariate logistic regression analysis were applied to identify the risk factors for the re-dislocation of children.

RESULTS

Eighty-six patients (99 hips) successively underwent the treatment. 69 hips were fixed at the first intention, 9 hips at the second intention, and a total of 78 hips with no re-dislocation occurred till the last follow-up with a rate of 78.8%. The univariate analysis showed that preoperative acetabular index (AI), International Hip Dysplasia Institute (IHDI) grade, intraoperative hip flexion angle, and intraoperative head-socket spacing were significantly related to the occurrence of re-dislocation after closed-reduction. The multivariate logistic regression analysis showed that preoperative AI > 40.5° ( OR=5.57, P<0.01), flexion angle < 80.5° ( OR=4.93, P<0.01) and head-socket distance > 6.95 mm ( OR=8.42, P<0.01) were risk factors for the re-dislocation. The area under the receiver operator characteristic curve was 0.91 when preoperative AI > 40.5°, flexion angle < 80.5°, head-socket distance > 6.95 mm, and IHDI grade were used to predict the occurrence of re-dislocation, and the sensitivity and specificity were 0.72 and 0.87, respectively.

CONCLUSIONS

Preoperative AI > 40.5°, intraoperative hip flexion angle < 80.5°, and head-socket distance > 6.95 mm are risk factors for postoperative re-dislocation in children with DDH. These risk factors combining with the IHDI grade would be better to predict the occurrence of re-dislocation.

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.

Prolonged Brace Treatment Does Not Result in Improved Acetabular Indices in Infantile Dislocated Hips

BACKGROUND

The Pavlik harness (PH) is commonly used to treat infantile dislocated hips. However, significant variability exists in the duration of brace treatment after successful reduction of the dislocated hip. The purpose of this study was to evaluate the effect of prescribed time in brace on acetabular index (AI) at two years of age using a prospective, international, multicenter database.

METHODS

We retrospectively studied prospectively enrolled infants with at least 1 dislocated hip that were initially treated with a PH and had a recorded AI at 2-year follow-up. Subjects were treated at 1 of 2 institutions. Institution 1 used the PH until they observed normal radiographic acetabular development. Institution 2 followed a structured shorter brace treatment protocol. Hip dislocation was defined as <30% femoral head coverage at rest on the pretreatment ultrasound or International Hip Dysplasia Institute (IHDI) grade III or IV on the pretreatment radiograph.

RESULTS

Fifty-three hips met our inclusion criteria. Hips from Institution 1 were treated with a brace ×3 longer than hips from institution 2 (adjusted mean 8.9±1.3 vs. 2.6±0.2 mo) (P<0.001). Institution 1 had an 88% success rate and institution 2 had an 85% success rate at achieving hip reduction (P=0.735). At 2-year follow-up, we observed no significant difference in AI between Institution 1 (adjusted mean 25.6±0.9 degrees) compared with Institution 2 (adjusted mean 23.5±0.8 degrees) (P=0.1). However, 19% of patients from Institution 1 and 44% of patients from Institution 2 were at or below the 50th percentile of previously published age-matched and sex-matched AI normal data (P=0.049). Also, 27% (7/26) of hips from Institution 1 had significant acetabular dysplasia (more than 2 SD from the mean), compared with a 22% (6/27) from Institution 2 (P=0.691). We found no correlation between age at initiation of bracing and AI at 2-year follow-up (P=0.071).

CONCLUSIONS

The PH brace can successfully treat dislocated infant hips, however, prolonged brace treatment was not found to result in improved acetabular development at 2-year follow-up.

LEVEL OF EVIDENCE

Level III.

Teardrop and sourcil line (TSL): a novel radiographic sign that predicts residual acetabular dysplasia (RAD) in DDH after closed reduction

BACKGROUND

Residual acetabular dysplasia (RAD) is a major problem of developmental dysplasia of the hip (DDH) after closed reduction (CR). Several parameters have been investigated as ways of predicting RAD; however, prediction of RAD remains controversial. The purpose of this study was to evaluate the radiographic sign of teardrop and sourcil line (TSL) in pediatric patients with DDH to enable prediction of RAD after CR.

METHODS

One hundred and twenty-five hips with DDH treated with CR and followed up for at least 2 years were included in this study. The mean age at CR was 18.3 months (range, 9 to 32 months) and the average follow-up time was 50.2 months (range, 24 to 89 months). The acetabular index (AI) was measured at different time points. The cases were divided into two groups according to whether TSL became continuous or not. The relationships among TSL, AI and RAD were analyzed.

RESULTS

The RAD incidence was 73.6% (92/125) at the last follow-up. AI at CR and TSL were the prognostic factors for RAD (P=0.017 and 0.001, respectively). Thirty-four hips showed a continuous TSL. There was a lower RAD rate in the TSL continuous group (P<0.001). There was no statistical difference in the AI at CR between the TSL continuous and discontinuous groups; however, the level of AI after CR was lower in the TSL continuous group. The TSL of 74% (20/27) hips became continuous after acetabular osteotomy surgery.

CONCLUSIONS

The TSL continuous group had a lower AI and incidence of RAD than the discontinuous group. The TSL can be a predictive factor of RAD in DDH after CR and restore the continuous of TSL maybe a potential parameter that can help surgeons to make a judgment intra-operation.

Epidemiological investigation and ultrasonic diagnosis of developmental dysplasia of the hip in Chinese infants: A large multi-center cohort study

Developmental dysplasia of the hip (DDH) is common among Chinese infants, but a lack of large-scale, multi-center epidemiological studies has made it difficult to characterize the risk factors associated with this disease.This multi-center cohort study included 19,833 Chinese infants aged 14 days to 6 months. A multi-center ultrasound protocol was used to diagnose hip abnormalities, and epidemiological data of the infants were collected through questionnaires. Categorical variables were expressed as percentages and compared using χ2 test. Multivariate analysis was performed through logistic regression.Of 19,833 infants, 345 had DDH (1.7%). DDH incidence was higher in female infants (n = 279) than in male infants (n = 66) (χ2 = 95.89, P < .05), and there were more left hip cases (n = 149) than right hip cases (n = 79) (χ2 = 12.49, P < .05). DDH incidence was statistically different amongst different age groups in months (χ2 = 451.71, P < .05), and it gradually decreased with age (P < .05). The prevalence of a positive DDH family history, breech presentation, oligohydramnios, swaddling style, and other musculoskeletal deformities was higher in the positive group than in the negative group (all P < .05). No significant differences were found in terms of delivery by cesarean section, multiple births, or premature birth between both groups.Family history, breech presentation, oligohydramnios, musculoskeletal deformities, and female sex are high-risk factors for DDH in Chinese infants. The incidence of DDH gradually decreases with age. The results of this study provide evidence for the epidemiology of infant DDH in China.

Case report: Morphological changes evident after manual therapy in two cases of late-diagnosed developmental dysplasia of the hip

BACKGROUND

Late diagnosed Developmental Dysplasia of the Hip (DDH) is the detection of DDH after 3 months of age and is associated with significantly poorer outcomes than when diagnosed and managed early. Late diagnosed DDH has lower rates of success with bracing, higher rates of surgery and higher rates of complications, including avascular necrosis of the femoral head and early osteoarthritis of the hip. We describe two cases of late-diagnosed DDH which demonstrated changes in femoroacetabular joint morphology on radiographic interpretation after a 6-month trial period of manual therapy.

CASE PRESENTATION

Two cases (13 and 30 months of age) with late-diagnosed DDH presented to a private chiropractic clinic for conservative, non-bracing management. One case had unilateral DDH and the other bilateral DDH. A trial of manual therapy was utilized over a 6-month period. Both cases demonstrated changes to femoroacetabular morphology as well as improvements in gross motor activity and lower extremity muscle tone.

CONCLUSION

Manual therapy, as an adjunct or alternative to static bracing, may be of benefit in individuals with late-diagnosed DDH not responding to bracing, and prior to more invasive interventions. Additional cases of manual therapy-based management of this condition are required to inform the design of future trials to investigate this hypothesis.

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).

Epidemiology and costs of surgical treatment of developmental dysplasia of hip in the Brazilian Public Health System in a decade

Objective:

To describe and analyze the epidemiology and costs of surgical treatment of hip dysplasia in the Brazilian Public Health System.

Methods:

An ecological analytical study that evaluated a time series and the geographic distribution of surgical treatment of hip dysplasia in Brazil. Frequencies of cases, number of cases and associated factors were analyzed. Correlations, frequency maps and flow maps are presented and discussed.

Results:

During the study, 14,584 patients with dysplasia were admitted to hospitals according to Information Technology Department of the Public Health System. Patients underwent hospital treatment specific for dysplasia in 8,592 cases (at an average cost of R$ 2.225,50, total cost of R$ 19.124.086,25– updated values). In this group, mortality rate was 0.046% and mean hospitalization time was 4.41 days (standard deviation of 2,39 days). Age between 1 and 4 years (37.7%), female sex (64.5%) and white race (46%) were more frequent. Greater rates of specialists (R²=0.82; p<0.001), greater proportion of counties with high/very high human development index (R²=0.79; p<0.001), and higher per capita income (R²=0.68; p<0.001) correlated to greater rates of treatments undertaken per 1,000 live births (as per State of treatment). The factor most related to treatment rate per 1,000 live births (as per State of residence) was white race (R²=0.90; p<0.001). Southern states had higher treatment rates (as per State of residence, rate of 0.73/1,000), and Southeast states had greater absolute frequency of cases (46.7%) and greater flow of patients.

Conclusion:

The surgical treatment of hip dysplasia in Brazil occurs frequently, at relevant costs, and is distributed in a heterogenous and unequal fashion in the Public Health System. Southern states have a higher incidence of cases, and there is an association with racial and socioeconomic factors. There was no large variation in the incidence of cases over time.

Variability in Australian screening guidelines for developmental dysplasia of the hip

AIM

To assess the variability in Australian screening guidelines for developmental dysplasia of the hip (DDH).

METHODS

Ovid MEDLINE®, EMBASE, EMB Reviews-Cochrane, CINAHL, TRIP and grey literature were searched to identify screening guidelines for DDH. Key data items related to recommendations for timing and method of screening were extracted and summarised in a table format for qualitative analysis.

RESULTS

Seventeen guidelines met inclusion criteria, comprising nine Australian DDH screening guidelines and eight Child Health Books. The guidelines showed variation in recommendations for the examiner, specific screening methods used for high-risk groups, timing of examinations and recommendations for referral.

CONCLUSIONS

Variability exists within Australian DDH screening guidelines. Lack of knowledge regarding local screening guidelines may contribute to the current trend of increased incidence of late diagnosed DDH in Australia, reported in New South Wales, South Australia, and Western Australia. An evidence-based and consistent approach to DDH screening is necessary to minimise late detected cases.

Traditional Mongolian swaddling and developmental dysplasia of the hip: a randomized controlled trial

BACKGROUND

Mongolian traditional swaddling of infants, where arms and legs are extended with a tight wrapping and hips are in adduction position, may lead to abnormal maturation and formation of the hip joint; and is a contributing factor for developmental dysplasia of the hip (DDH). This hypothesis was tested in this randomized controlled trial.

METHODS

Eighty newborns with one or two hips at risk of worsening to DDH (Graf Type 2a; physiologically immature hips) at birth were randomized into 2 groups at a tertiary hospital in Ulaanbaatar. The "swaddling" group (n = 40) was swaddled in the common traditional Mongolian method for a month while the "non-swaddling" group (n = 40) was instructed not to swaddle at all. All enrollees were followed up on monthly basis by hip ultrasound and treated with an abduction-flexion splint if necessary. The groups were compared on the rate of Graf's "non-Type 1" hips at follow-up controls as the primary outcome. Secondary outcomes were rate of DDH and time to discharge (Graf Type 1; healthy hips). In addition, correlation between the primary outcome and swaddling length in days and frequency of swaddling in hours per day were calculated.

RESULTS

Recruitment continued from September 2019 to March 2020 and follow-up data were completed in June 2020. We collected final outcome data in all 80 enrollees. Percentages of cases with non-Type 1 hip at any follow-up examination were 7.5% (3/40) in the non-swaddling group and 40% (16/40) in the swaddling group (p = 0.001). There was no DDH case in the non-swaddling group while there were 8 cases of DDH in the swaddling group. The mean time to discharge was 5.1 ± 0.3 weeks in the non-swaddling group and 8.4 ± 0.89 weeks in the swaddling group (p = 0.001). There is a correlation between the primary outcome and the swaddling frequency in hours per day (r = 0.81) and swaddling length in days (r = 0.43).

CONCLUSIONS

Mongolian traditional swaddling where legs are extended and hips are in extension and adduction position increases the risk for DDH.

TRIAL REGISTRATION

Retrospectively registered, ISRCTN11228572 .

Developmental dysplasia of the hip: Beyond the screening. Physical exam is our pending subject

INTRODUCTION

Developmental dysplasia of the hip is a common cause of disability among children. Early detection leads to better prognosis. There are some risk factors that increase the possibility of developing a dysplasia. But not every child with developmental dysplasia has them. This means that physical examination is still very useful to detect them. However, based on clinical findings, the amount of requested ultrasound seems higher than it would be necessary.

METHODS

Retrospective cohort study of infants born in a single tertiary care centre. Babies in which hip ultrasound was performed were included. During the period of study, patients with diagnosis of developmental hip dysplasia were also included, as well as the amount of ultrasounds requested during this period, and their efficiency.

RESULTS

Out of the 456 newborns included, 530 hip ultrasounds were performed. Just 3 of the total 12 dysplasias had risk factors. The others were diagnosed through clinical examination.

CONCLUSIONS

Screening protocols are useful to detect hip dysplasia but clinical examination is very important to detect those cases without risk factors. However, the number of tests is higher than expected according to the diagnosed dysplasias.

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.

Team Approach: Developmental Dysplasia of the Hip

Developmental dysplasia of the hip (DDH) encompasses a wide spectrum of hip disorders, including neonatal instability, acetabular dysplasia, hip subluxation, and frank dislocation of the hip. It is a common disorder, with a reported incidence of between 0.1% and >10% of live births. Coordinated, interdisciplinary care is important to achieving successful outcomes. This starts with accurate assessment of risk factors in the prenatal period, thorough clinical examination by the primary care provider at all well-child visits, and early referral to a pediatric orthopaedic surgeon for prompt diagnosis and treatment. Early diagnosis and prompt treatment is critical for an excellent outcome. Ongoing, open communication between clinicians is essential for the effective coordination of care. Treatment options vary depending on the age of presentation. A Pavlik harness (dynamic hip abduction orthosis) is used for children up to 6 months of age. A more rigid abduction orthosis may be used if treatment with a Pavlik harness is unsuccessful, with a closed reduction and spica cast being the next step if needed for children up to 18 months of age. Finally, open reduction with possible concomitant femoral and/or pelvic osteotomies is the surgical option in an older child, when necessary. In general, the later the child is diagnosed with and treated for DDH, the greater the risk of a nonoptimal outcome. Depending on the severity of the condition, children with DDH may need to be followed closely until skeletal maturity so as not to miss the diagnosis of asymptomatic residual hip dysplasia, which can predispose patients to early hip arthritis.

Current Evidence about Developmental Dysplasia of the Hip in Pregnancy

In adults, developmental dysplasia of the hip (DDH) represents a spectrum of disorders. It is commonly found in women in routine orthopedic practice. Hip dysplasia is a leading precursor of joint laxity; when untreated, it can contribute to chronic modifications, such as thickening of the pulvinar and ligamentum teres (which can also elongate), hypertrophy of the transverse acetabular ligament, and osteoarthritis. DDH is presumed to be associated with alterations in pelvic morphology that may affect vaginal birth by the reduction in the transverse diameter of the pelvic inlet or outlet. Here, we provide an overview of the current knowledge of pregnancy-associated DDH. We primarily focused on how a surgical DDH treatment might influence the pelvic shape and size and the effects on the mechanism of birth. We presented the female pelvis from the standpoint of bone and ligament morphology relative to a pelvic osteotomy. Then, we described whether the pregnancy was impacted by previous surgical DDH treatments, performed from infancy to adulthood. In conclusion, hip dysplasia is not associated with high-risk complications during pregnancy or with increased difficulty in vaginal delivery.

Developmental Hip Dysplasia: An Epidemiological Nationwide Study in Italy from 2001 to 2016

Developmental Dysplasia of the Hip (DDH) includes a broad spectrum of hip abnormalities. DDH requires early diagnosis and treatment; however, no international consensus on screening protocol and treatment is provided in the literature. Epidemiological studies are helpful to understand the national variation of a specific surgical procedure and compare it with that of other countries. Data provided by different countries could allow researchers to provide international guidelines for DDH screening and treatment. Limited data are reported regarding trends of hospitalization for DDH, and no public database is available. The purpose of this study was to estimate annual admissions for DDH in Italian patients from 2001 to 2016, based on the hospitalization reports. Data of this study were collected from the National Hospital Discharge Reports (SDO) reported at the Italian Ministry of Health. Descriptive statistical analyses were performed. From 2001 to 2016, 3103 hospitalizations for DDH were recorded in Italy, with a mean incidence of 2.33 (per 100,000 young inhabitants). Females of the 0–4 years old group represented the majority of patients hospitalized for DDH.

Developmental hip dysplasia and hip ultrasound frequency in a large American payer database

Developmental dysplasia of the hip (DDH) is an important contributor to musculoskeletal morbidity, but effective strategies to screen for DDH remain controversial. The current utilization of hip ultrasound (US) screening for DDH in the United States is not defined. This study utilized Optum's de-identified Clinformatics® Data Mart, a large commercial and Medicare Advantage claims database. The frequency of DDH and hip US utilization was estimated using billing data on an average of 2.9 million relevant beneficiaries included annually from 2007 through 2017. A total of 6806 DDH cases were identified with an average annual prevalence of 1.7 per 1000 infants, which was stable during the study period. Girls were more likely to be screened and diagnosed with DDH, comprising 72% of DDH cases with an OR of 2.55 (95% CI 2.42-2.69), p < 0.001. Hip US screening was employed in 0.9% of the infant population on average but increased substantially from 2007 (0.4%) to 2017 (2.2%). Most common billing diagnoses included hip deformity (27.4%), breech delivery (20.4%), and physical exam abnormality (17.7%). The average imaging costs per patient for all screened children was $108.94. Insurance claims reflect the current American practice of selective hip US with relative adherence to American Academy of Pediatrics guidelines based on reported diagnoses. While hip US utilization increased during the study period, prevalence of DDH diagnoses did not increase. Our results suggest that expansion of hip US screening may not effectively increase DDH detection although further investigation is needed to ascertain optimal screening strategies to improve patient outcomes.

Early detection of developmental dysplasia of hip by ultrasound

OBJECTIVE

To assess the effectiveness of early universal ultrasound (US) screening of developmental dysplasia of the hip (DDH).

STUDY DESIGN

A prospective study of universal hip screening of all mature neonates was conducted from 2012 to 2013, at the Department of Obstetrics and Gynaecology, University of Szeged; 1636 newborns (3272 hips) had clinical examinations and hip ultrasound by the Graf method within the1st 3 days of life. Prevalence of DDH, risk factors, sensitivity and specificity of clinical examinations were evaluated.

RESULTS

At the 1st US, 70 of the examined 3272 hips (2.14%) were found to be positive. According to Graf categories, the following distribution was observed: type II C, 21 hips (30.0%); D, 24 hips (34.28%); III, 24 hips (34.28%); IV, 1 hip (1.44%). Regarding the risk factors, female gender, breech presentation and positive family history proved to be significant. Interestingly, 28 (50.90%) of the 55 newborns with DDH had neither positive physical signs nor any risk factors, except being female. The physical examination was calculated for sensitivity (20.0%) and specificity (98.34%).

CONCLUSIONS

In our 1-year period study, 50.9% of the newborns with DDH had neither any positive physical signs nor any risk factors, except being a female. In contrast, early universal US screening of the hip facilitated to diagnose all cases with hip dysplasia. Hip sonography is an effective mode of prevention in orthopaedics, however further studies are needed to compare the rates of operative procedures in selective versus universal screening models.

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.

Diagnostic Performance of a New Convolutional Neural Network Algorithm for Detecting Developmental Dysplasia of the Hip on Anteroposterior Radiographs

OBJECTIVE

To evaluate the diagnostic performance of a deep learning algorithm for the automated detection of developmental dysplasia of the hip (DDH) on anteroposterior (AP) radiographs.

MATERIALS AND METHODS

Of 2601 hip AP radiographs, 5076 cropped unilateral hip joint images were used to construct a dataset that was further divided into training (80%), validation (10%), or test sets (10%). Three radiologists were asked to label the hip images as normal or DDH. To investigate the diagnostic performance of the deep learning algorithm, we calculated the receiver operating characteristics (ROC), precision-recall curve (PRC) plots, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) and compared them with the performance of radiologists with different levels of experience.

RESULTS

The area under the ROC plot generated by the deep learning algorithm and radiologists was 0.988 and 0.988-0.919, respectively. The area under the PRC plot generated by the deep learning algorithm and radiologists was 0.973 and 0.618-0.958, respectively. The sensitivity, specificity, PPV, and NPV of the proposed deep learning algorithm were 98.0, 98.1, 84.5, and 99.8%, respectively. There was no significant difference in the diagnosis of DDH by the algorithm and the radiologist with experience in pediatric radiology (p = 0.180). However, the proposed model showed higher sensitivity, specificity, and PPV, compared to the radiologist without experience in pediatric radiology (p < 0.001).

CONCLUSION

The proposed deep learning algorithm provided an accurate diagnosis of DDH on hip radiographs, which was comparable to the diagnosis by an experienced radiologist.

Impact of presence of ossific nucleus on results of closed reduction in treatment of developmental dysplasia of the hip (302 hips)

Closed reduction is an effective treatment method for developmental dysplasia of the hip (DDH). Still, there are certain controversial issues regarding the timing of the treatment. In this study, we investigated the results of closed reduction and Outcomes of 302 hips of 218 patients treated with closed reduction have been analyzed retrospectively. One hundred fifty-two hips that had ossific nucleus [ossific nucleus (+)] during reduction have been compared with 150 hips that had no ossific nucleus [ossific nucleus (-)] during reduction. Also, the patients have been divided into two groups, the patients treated with closed reduction before the sixth month and the patients treated with closed reduction after the sixth month. Groups have been compared between themselves in terms of avascular necrosis (AVN) and redislocation. Seventy-seven of the 112 hips treated with closed reduction in the first six months were ossific nucleus (-), and AVN has been noted in 5 (6%) patients. However, although no AVN has been seen in any of the 35 ossific nucleus (+) hips, no statistically significant difference has been found between two groups. Seventy-three of the 190 hips treated with closed reduction after the sixth month were ossific nucleus (-), and AVN has been seen in 13 (17%) of these hips. AVN has been seen in 9 (7%) of the 117 ossific nucleus (+) hips. The AVN ratio was found significantly lower in the ossific nucleus (+) hips (P < 0.034). Although the presence of ossific nucleus does not provide extra protection against AVN in before the sixth month, the presence of ossific nucleus is protective against AVN after the sixth month.

Developmental dysplasia of the hip: can contrast-enhanced MRI predict the development of avascular necrosis following surgery?

OBJECTIVE

To investigate the performance of contrast-enhanced MRI for predicting avascular necrosis (AVN) of the treated femoral head after surgical reduction for developmental dysplasia of the hip (DDH) using qualitative and quantitative methods.

METHODS AND MATERIALS

This IRB-approved, HIPAA compliant retrospective study included 47 children who underwent same-day contrast-enhanced MRI following unilateral surgical hip reduction between April 2009 and June 2018. Blinded to the clinical outcome, 3 reviewers (2 pediatric radiologists and 1 pediatric orthopedist) independently categorized the enhancement pattern of the treated femoral head. Signal intensities, measured using regions of interest (ROI), were compared between treated and untreated hips and percent enhancements were compared between hips that developed and did not develop AVN. Post-reduction radiographs were evaluated using Salter's criteria for AVN and Kalmachi and MacEwen's classification for growth disturbance. Non-parametric tests and Fisher exact test were used to compare enhancement values between AVN and non-AVN hips. Bonferroni correction was used for multiple comparisons.

RESULTS

Ten (21%) out of the 47 children (7 boys and 40 girls; mean age 9.0 ± 4.7 months) developed AVN. Age at surgical reduction was significantly higher (p = 0.03) for hips that developed AVN. No significant differences were found in gender (p = 0.61), laterality (p = 0.46), surgical approach (p = 0.08), history of pre-operative bracing (p = 0.72), abduction angle (p = 0.18-0.44), enhancement pattern (p = 0.66-0.76), or percent enhancement (p = 0.41-0.88) between AVN and non-AVN groups.

CONCLUSION

Neither enhancement pattern nor percent enhancement predicted AVN, suggesting that post-reduction conventional MRI does not accurately distinguish between reversible and permanent vascular injury.

Developmental dysplasia of the hip screening programme in Chile

PURPOSE

Developmental dysplasia of the hip (DDH) encompasses a wide pathological spectrum, from mild acetabular dysplasia to complete congenital hip dislocation at birth. Screening policies have been implemented in an effort to effectively identify and treat patients with DDH. Since 2009 there has been a national DDH programme in Chile. The current study evaluates the results of the programme in patients born between 2010 and 2015.

METHODS

Records of patients hospitalized from 1st January 2010 to 31st December 2019 were retrieved from national databases. Those born from 1st January 2010 to 31st December 2015 who underwent a procedure for DDH under general anaesthesia during their first five years of life were selected. Sex, first surgical procedure and age at first surgical procedure were analyzed. The incidence of DDH that required major surgical treatment was calculated.

RESULTS

A total of 961 children born from 1st January 2010 to 31st December 2015 underwent a procedure for DDH during their first five years of life. The number of major procedures was significantly lower than the number of minor procedures (269 vs 692). The incidence of major procedures was 0.18 per 1000 live births. Girls underwent a higher number of procedures than boys (831 vs 130), whereas 39.2% of the boys and 26.2% of the girls had major procedures. The mean age at the time of the first procedure was 15.35 months (sd 10.09; range 0.03 to 55.92 months).

CONCLUSION

The present study suggests that the Chilean National DDH Screening Program is an appropriate programme with substantial benefits with respect to public health.

LEVEL OF EVIDENCE

II.

3-D Ultrasound Imaging Reliability of Measuring Dysplasia Metrics in Infants

Developmental dysplasia of the hip is a hip abnormality that ranges from mild acetabular dysplasia to irreducible femoral head dislocations. While 2-D B-mode ultrasound (US)-based dysplasia metrics or disease metrics are currently used clinically to diagnose developmental dysplasia of the hip, such estimates suffer from high inter-exam variability. In this work, we propose and evaluate 3-D US-derived dysplasia metrics that are automatically computed and demonstrate that these automatically derived dysplasia metrics are considerably more reproducible. The key features of our automatic method are (i) a random forest-based learning technique to remove regions across the coronal axis that do not contain bone structures necessary for dysplasia-metric extraction, thereby reducing outliers; (ii) a bone segmentation method that uses rotation-invariant and intensity-invariant filters, thus remaining robust to signal dropout and varying bone morphology; (iii) a novel slice-based learning and 3-D reconstruction strategy to estimate a probability map of the hypoechoic femoral head in the US volume; and (iv) formulae for calculating the 3-D US-derived dysplasia metrics. We validate our proposed method on real clinical data acquired from 40 infant hip examinations. Results show a considerable (around 70%) reduction in variability in two key 3-D US-derived dysplasia metrics compared with their 2-D counterparts.

Inter-Gender Pelvic Shape Variations as a Cause of DDH Overdiagnosis

Objective

Developmental dysplasia of the hip (DDH) is an abnormal relationship between the acetabulum and the head of the femur. Plain x-ray of both hips at the age of 3 months is still in use in some countries. On plain films, classic lines and angles are evaluated to meet current guidelines for positive DDH. Among these is the acetabular angle (AA), which most did not exceed 30° in normal pelvis regardless of gender. A flat promontory gives the impression of a high AA angle, whereas a sharp promontory gives the impression of a low AA angle.

Materials and Methods

All anteroposterior (AP) pelvic digital x-ray studies performed to rule out DDH were collected from the PACS systems. A novel angle was measured between a line parallel to the lateral aspect of the region of the inferior iliac spines and a line that extends along the acetabular roof to quantify the roundness of the iliac promontory. We called the former line the Miral line and the formed angle the iliac promontory angle.

Results

We show that the promontory shape is significantly different between genders, and therefore it is mistaken to generalize an upper AA limit for males and females. In addition, we show that the current guideline of the upper limit of AA did not predict the incidence of DDH.

Conclusion

We suggest that the current practice is introducing a high rate of false positive, especially among females, and the current guidelines on AA should be reviewed and assigned separately for males and females. This is more important for countries that did not utilize the ultrasonographic assessment for DDH.

Recommendations for early diagnosis of Developmental Dysplasia of the Hip (DDH): working group intersociety consensus document

This consensus document has been prepared by a multidisciplinary group of experts (Paediatricians, Radiologists, Paediatric Orthopaedics) and it is mainly aimed at paediatricians, hospitals and primary care providers. We provide recommendations for the early diagnosis and treatment of Developmental Dysplasia of the Hip (DDH) and indications on its management.

[Develomental dysplasia of the hip: beyond the screening. Physical exam is our pending subject]

INTRODUCTION

Developmental dysplasia of the hip is a common cause of disability among children. Early detection leads to better prognosis. There are some risk factors that increase the possibility of developing a dysplasia. But not every child with developmental dysplasia has them. This means that physical examination is still very useful to detect them. However, based on clinical findings, the amount of requested ultrasound seems higher than it would be necessary.

METHODS

Retrospective cohort study of infants born in a single tertiary care centre. Babies in which hip ultrasound was performed were included. During the period of study, patients with diagnosis of developmental hip dysplasia were also included, as well as the amount of ultrasounds requested during this period, and their efficiency.

RESULTS

Out of the 456 new-borns included, 530 hip ultrasounds were performed. Just 3 of the total 12 dysplasias had risk factors. The others were diagnosed through clinical examination.

CONCLUSIONS

Screening protocols are useful to detect hip dysplasia but clinical examination is very important to detect those cases without risk factors. However, the number of tests is higher than expected according to the diagnosed dysplasias.

Should I Plan to Open? Predicting the Need for Open Reduction in the Treatment of Developmental Dysplasia of the Hip

BACKGROUND

Closed reduction is generally attempted on children under 18 months of age who present as older infants or who fail nonoperative management for developmental dysplasia of the hip (DDH). However, many of these patients will not achieve concentric reduction by closed means and will ultimately require open reduction (OR). Limited evidence exists to predict which patients can be adequately closed reduced versus those who will need open treatment.

METHODS

Prospectively collected data from 4 select centers of an international multicenter study group sharing a common treatment approach were reviewed for all DDH infants under 18 months old that required operative management. Patients were categorized into 2 groups: those whose hips were successfully closed reduced or those who ultimately required OR. Factors were compared between the closed reduction and OR groups for 2 separate cohorts-those presenting early in life with ultrasound (US) data, and those presenting later with radiographic data.

RESULTS

A total of 154 patients (166 hips) were included in the analysis. Overall, 87.3% were female. In the early-presenting cohort, purposeful entry multivariate regression revealed that patients with Graf IV hips on US had 3.8 times higher odds of requiring an OR. For the later cohort, hips that were clinically irreducible (ie, negative Ortolani sign) had 3.3 times higher odds of requiring OR. Patients with International Hip Dysplasia Institute (IHDI) grade IV hips had 2.5 times higher odds of needing an OR versus those with grade III hips and 15.4 times higher odds than those with grade II hips. Children with an IHDI grade IV hip and a negative Ortolani sign had 4.4 times higher odds of needing OR.

CONCLUSION

Children younger than 18 months with dislocated hips who require OR are more likely to have a high-grade radiographic dislocation (IHDI grade IV), negative preoperative Ortolani sign, and a Graf IV classification on initial US. This information may help surgeons budget the use of operating room time and better counsel parents about intraoperative expectations.

LEVEL OF EVIDENCE

Level III-Prognostic.

Significance of Asymmetry of Groin and Thigh Skin Creases in Developmental Dysplasia of the Hip Revisited: Results of a Comparative Study

BACKGROUND

No high level of scientific evidence exists about the use of asymmetry of skin creases (ASC) on the groin and thigh regions in diagnosing developmental dysplasia of the hip. The aim of this comparative study was to revisit whether or not ASC was a significant clinical finding in developmental dysplasia of the hip.

METHODS

This was retrospective analysis of a prospectively collected data. Control group was composed of 1000 consecutive healthy infants (mean age, 46.7 d) whose both hips were considered Graf type I (normal). Study group (SG) was composed of 246 consecutive patients (mean age, 96.5 d) whose treatments by abduction bracing were initiated due to unilateral or bilateral Graf type IIa(-) and worse hips.

RESULTS

SG included 178 patients with bilateral or unilateral dysplastic hips [Graf type IIa(-), IIb, IIc] and 68 patients with at least 1 decentered hip (Graf type D, III, IV). ASC was seen in 63 of 101 patients (63%) having positive clinical finding(s). The rates of both ASC alone (P<0.001; odds ratio, 3.46) and ASC total (ASC with and without additional findings) (P<0.0001; odds ratio, 7.48) were significantly higher in SG than in control group. ASC was the only clinical finding in 31 patients and 24 of these 31 patients (77%) had unilateral or bilateral dysplastic hips. Sensitivity and specificity of ASC alone were 12.60% and 96.00%, respectively. ASC was accompanied by other clinical findings (mostly Galeazzi sign and limitation of abduction) in 32 patients and 23 of these 32 patients (72%) had at least 1 decentered hip. Sensitivity and specificity of ASC total were 25.61% and 95.60%, respectively.

CONCLUSIONS

ASC is a significant finding, as there is considerable increased risk of having dysplastic or decentered hips in infants having such a finding alone or associated with other findings. ASC alone is more commonly seen in patients with dysplastic hip(s) whereas ASC is mostly accompanied with other clinical finding(s) in patients with decentered hip(s). This study shows that, ASC can be introduced as a risk factor in selected newborn hip screening programs.

LEVEL OF EVIDENCE

Level II-diagnostic study.

Interpreting neonatal hip sonography: intraobserver and interobserver variability

The purpose of this study is to state the reliability of neonatal hip ultrasound interpretation, defining the intra and interoperator variability in the evaluation of the scans. We considered a sample of 2071 scans (coming from 798 patients who attended the screening programme for hip dysplasia), which were interpreted by the operator who obtained and read the images at the screening time and then by a different operator who saw the images for the first time. Both the intra and interoperator variability of α and β angles' values resulted statistically not significative (intraclass correlation coefficient > 0.8) and determining a class shift (according to the Graf's classification) in a nonstatistically significative number of cases (agreement percentage >91% and Cohen's κ >0.8). Hip sonography can reliably detect hip dysplasia and the intra and interoperator variability in the interpretation of the exam is NS when the examination is correctly executed.

Citation analysis of the highest-cited articles on developmental dysplasia of the hip

The purpose of this study is to determine the highest-cited articles on developmental dysplasia of the hip (DDH) and analyze their bibliometric characteristics. We searched the Web of Science (WoS) for articles with the highest number of citations on DDH and recorded their number of citations in WoS, Scopus, and Google Scholar (GS). We ranked and selected the top 100 cited articles. The average number of citations in WoS was 148 (range 66-638). The most-cited article in all databases was Crowe's total hip replacement cohort on DDH. The Journal of Bone and Joint Surgery American Volume (n = 35) had the most articles in the list, and the United States (n = 46) contributed with the most articles. The University of Bern had the most publications (n = 8). Most studies were therapeutic (n = 45) or diagnostic (n = 29). Hip preservation and arthroplasty investigations have had an increment in citations in recent decades. We provide an historical perspective on research conducted on DDH. A majority of the articles were observational and therapeutic. All databases had good correlation in the number of citations.