Genetics of hip dysplasia - a systematic literature review.

BACKGROUND: Developmental dysplasia of the hip (DDH) is a congenital condition affecting 2-3% of all newborns. DDH increases the risk of osteoarthritis and is the cause of 30% of all total hip arthroplasties in adults < 40 years of age. We aim to explore the genetic background of DDH in order to improve diagnosis and personalize treatment. METHODS: We conducted a structured literature review using PRISMA guidelines searching the Medline, Embase and Cochrane databases. We included 31 case control studies examining single nucleotide polymorphisms (SNPs) in non-syndromic DDH. RESULTS: A total of 73 papers were included for full text review, of which 31 were single nucleotide polymorphism (SNP) case/control association studies. The literature review revealed that the majority of published papers on the genetics of DDH were mostly underpowered for detection of any significant association. One large genome wide association study has been published (N = 9,915), establishing GDF5 as a plausible risk factor. CONCLUSIONS: DDH is known to be congenital and heritable, with family occurrence of DDH already included as a risk factor in most screening programs. Despite this, high quality genetic research is scarce and no genetic risk factors have been soundly established, prompting the need for more research.

Maternal perceptions and awareness regarding developmental dysplasia of the hip in children among mothers and pregnant women in Makkah City, Saudi Arabia.

Background: Developmental dysplasia of the hip (DDH) is a spectrum of disorders that develop in utero, involving the femoral head and acetabular cup development, ranging from dysplasia to dislocation. The prevalence of DDH in Saudi Arabia is 10.46 per 1000 live births. However, the late presentation of DDH in Saudi Arabia is around 30%, believed to be significantly due to a lack of awareness of the disease among mothers and pregnant women. Aims: This study aimed to measure maternal perceptions and awareness regarding DDH in children among mothers and pregnant women in Makkah City, Saudi Arabia. Method: In total, 406 women participated in an electronic survey. The survey questions were adapted from previously published research, and the questionnaire was available in Arabic. Results: The age distribution of the participants ranged from below 20 to over 50 years, with the largest group being 31-40 years old. Most of the participants had a university-level education (61.1%). The overall assessment showed a predominance of poor knowledge (41.1%), followed by good knowledge (34.7%), and then medium knowledge (24.1%). Conclusion: The present study revealed significant knowledge gaps and barriers to the early detection and intervention of DDH among Makkah City mothers and pregnant women. The findings underscore the need for targeted educational campaigns, increased access to screening programs, and heightened healthcare provider knowledge to improve DDH's perception and awareness. Future interventions should focus on addressing these gaps and promoting early detection and intervention strategies to minimize the long-term consequences of DDH.

Association Between Alpha Angle and Acetabular Index in Screening for Developmental Dysplasia of the Hip.

BACKGROUND: Developmental dysplasia of the hip (DDH) is a critical orthopedic condition ranging from minor hip joint instability to complete dislocations, demanding early intervention to avoid severe complications, especially in children. In Mexico, stringent regulations under the Norma Oficial Mexicana (NOM) mandate hip screening for pediatric patients. The primary objective of this study is to investigate the relationship between alpha angles and the acetabular index in patients at six months of age, aiming to determine whether an increase in the alpha angle correlates with a better acetabular index. METHODS: We included 120 patients who were screened for hip issues with Graf's methodology in June 2023 and September 2023 at the General Hospital of Mexico "Dr. Eduardo Liceaga" in Mexico City before three months of age and attended their follow-up appointment at six months of age, where acetabular index measurement was performed using the Carestream platform on institutional X-rays. RESULTS: In our statistical analysis, we obtained a statistically significant relationship between an increase in the left hip alpha angle and a decrease in the left hip acetabular index (p=0.015) although it was not significant for an acetabular index of less than 25° (p=0.055). A significant relationship was observed between the right hip acetabular index and the right hip alpha angle (p=0.017) but not significant for an acetabular index less than 25° (p=0.10). CONCLUSION: Universal hip screening is crucial for the early detection of DDH. Our study emphasizes using alpha-angle measurements (>70°) as reliable indicators of normal hip health.

Rates and risk factors for failure of reduction in closed reduction in developmental dysplasia of the hip: a systematic review and meta-analysis.

Objective: In developmental dysplasia of the hip (DDH), concentric reduction of dislocated hips cannot be achieved by closed reduction in many cases, and open reduction is required ('failure of reduction'). The incidence of cases requiring open reduction and the significance of risk factors for unsuccessful reduction remain unclear. We investigated the overall rate and the risk factors for failed closed reduction in DDH. Methods: We followed the Cochrane recommendations in our systematic review and meta-analysis. We performed a systematic search in three medical databases to identify all studies reporting on pediatric patients with hip dislocation in DDH on 2 July 2022. Eligible studies reported on the rate of failure in children younger than 36 months. We calculated odds ratios (ORs) with 95% CIs from two-by-two tables (event rate in risk group, event rate in non-risk group). Results: We identified 13 316 studies and included 62 studies (5281 hips) for failure rate and 34 studies (3810 hips) for risk factor analysis. The overall rate of failure in closed reduction was 20%. The risk of failure of reduction increased with the grade of dislocation and was significantly higher for high dislocations (group 0-24: IHDI 4 vs IHDI 2 OR: 17.45, CI: 9.26-32.92; Tönnis 4 vs Tönnis 2 OR: 14.67, CI: 1.21-177.37; Graf IV vs Graf III OR: 3.4, CI: 2.27-5.09). Male gender was also a significant risk factor (OR: 2.27, CI: 1.13-4.56) in group 0-36. Conclusion: Higher grade dislocations and male gender are significant risk factors for failure of reduction in closed reduction in hip dislocation in DDH.

Mid-Term to Long-Term Outcomes and Complications of Total Hip Arthroplasty in Patients Who Have Crowe IV Developmental Dysplasia of the Hip: A Systematic Review and Meta-Analysis.

BACKGROUND: Severe forms of developmental dysplasia of the hip (DDH) in adulthood often lead to total hip arthroplasty (THA). This study aimed to evaluate the mid-term to long-term outcomes of THA in Crowe type IV DDH cases, which represent a technically challenging and complex patient group. METHODS: PubMed, EMBASE, Web of Science, and Scopus were searched for observational studies and case series with over 100 months of mean follow-up on adult patients who had Crowe type IV DDH treated with THA. A total of 3,710 records were initially identified, leading to the inclusion of 24 studies in the final analysis. These studies were subjected to quality assessment using the National Institutes of Health Quality Assessment tool. Various outcomes including revision rates, leg-length discrepancy, Harris Hip Score, and complications like periprosthetic joint infections, dislocations, and nerve injuries were analyzed. A random effects model was employed for statistical analysis, with sensitivity analysis and metaregression applied in cases of high heterogeneity. RESULTS: The included studies assessed 1,024 hips with a mean follow-up of 11 years, revealing improvements in Harris Hip Score and reductions in leg length discrepancy post-THA. However, notable challenges were noted, including a 10.7% rate of intraoperative fractures, a 1.8% periprosthetic joint infection rate, and a 5.8% dislocation rate. Osteolysis and aseptic loosening revisions were observed in 9.1 and 8% of cases, respectively. Heterotopic ossification occurred in 11.1% of patients. Nerve injury was reported in 4.2% of cases. With the use of metaregression, some factors for observed heterogeneity were identified. CONCLUSIONS: Total hip arthroplasty (THA) in Crowe type IV DDH patients presents notable challenges, but can lead to substantial long-term improvements in patient-reported outcomes. LEVEL OF EVIDENCE: IV.

Interpretation and Natural History of Asymmetric Skin Folds in Infants With Developmental Dysplasia of the Hip.

The association between asymmetric skin folds (ASFs) of the gluteal, groin, or thigh regions and ipsilateral developmental dysplasia of the hip (DDH) has not been elucidated yet. Why are ASFs formed in some infants with DDH? Do DDH-associated ASFs persist during childhood and adulthood? Is it possible for ASFs to emerge without DDH pathology? Three cases of acute and chronic hip pathology in adults are presented in an attempt to explain the formation and the natural history of ASFs in infants with DDH. It is suggested that ASFs are formed when the excess soft tissues of the thigh shrink over a short femur. On the other hand, ASFs disappear after the length of the thigh is restored and the soft tissues of the thigh are re-stretched. This telescoping mechanism of the formation and disappearance of ASFs is applicable regardless of the underlying hip pathology or the age of the patient.

Gradual Reduction Using Overhead Traction for Late-Detected Developmental Dysplasia of the Hip: A Report of Three Cases Diagnosed Among Children Over Four Years Old.

Optimal reduction methods for late-detected developmental dysplasia of the hip (DDH) remain debatable. Gradual reduction (GR) using traction is a safer and more reliable option for late-detected DDH than closed reduction or open reduction with or without preliminary traction. GR using overhead traction, one of the current GR methods, has been indicated for children of walking age up to four years of age, whereas the upper age limit of this method has not yet been determined. We present three cases of late-detected DDH whose hips were treated between four and six years of age with this method. Stable reduction without subsequent redislocation was technically accomplished for all patients, albeit the duration of horizontal traction became longer than usual. Clinically significant avascular necrosis (AVN) has developed in children aged ≥5 years, indicating the need for some modifications to the conventional protocol to prevent AVN.

Developmental Dysplasia of the Hip and Laterality: The Importance of Graded Severity of the Contralateral Hip.

Background: Laterality and bilaterality have been reported as prognostic variables in developmental dysplasia of the hip (DDH) outcomes. However, there is little clarity across the literature on the reporting of laterality in developmental dysplasia of the hip (DDH) due to the variability in severity of the condition. It is widely accepted that the left hip is most frequently affected; however, the true incidence of unilateral left, unilateral right and bilateral cases can be hard to quantify and compare across studies. The purpose of this study was to examine laterality accounting for graded severity in a multi-centre, international prospective observational study of infants with hip dysplasia to demonstrate the complexity of this issue. Methods: A multi-centre, prospective hip dysplasia database was analyzed from 2010 to April 2015. Baseline diagnosis was used to classify patients into a graded laterality category accounting for hip status within the DDH spectrum. Results: A total of 496 patients were included in the analysis; 328 were <6 months old at diagnosis and 168 were between 6 and 18 months old. Of these patients, 421 had at least one frankly dislocated hip. Unilateral left hip dislocations were most common, with 223 patients, followed by unilateral right and bilateral dislocations with 106 and 92 respectively. Stratifying these patients based on status of the contralateral hip, 54 unilateral left and 31 unilateral right dislocated patients also had a dysplastic or unstable contralateral hip. There were significantly fewer bilateral patients in the 6 to 18-month group (p = 0.0005). When classifying laterality by affected hip, bilaterality became the predominant finding, comprising 42% of all patients. Conclusions: Findings from this multi-centre prospective study demonstrate the necessity to account for the graded severity in hip status when reporting DDH laterality. To accurately compare laterality across studies, a standardized, comprehensive classification should be established, as contralateral hip status may impact prognosis and treatment outcomes. Level of Evidence: Level II Prognostic Study.

The Feasibility of Prenatal Ultrasonic Screening for Developmental Dysplasia of the Hip.

BACKGROUND: developmental dysplasia of the hip (DDH) is a condition characterized by abnormal hip development in infancy. Early diagnosis allows for effective treatment, while late presentation often necessitates complex surgical interventions. Current recommendations advise screening between the 6th and 8th week postnatal using an ultrasound, typically employing the Graf method. However, there is no universal consensus on whether ultrasound screening significantly increases treatment likelihood compared to clinical examination-guided ultrasound. This study aims to explore the feasibility of prenatal ultrasound for the early identification of DDH risk. METHODS: This prospective observational study involved 100 pregnant women undergoing fetal hip ultrasounds during the second and third trimesters. Using the modified Graf method, alpha and beta angles were calculated on the fetus. Postnatally, alpha and beta angles were compared with the prenatal values. RESULTS: Prenatal ultrasound at the 24th week showed inconclusive results because of the difficulty in identification of Graf landmarks, while ultrasound at the 34th week proved to be a reliable and safe method for the quantitative determination of alpha and beta angles. Significant correlations were found between prenatal and postnatal alpha and beta angles. Moreover, significant differences in prenatal alpha and beta values were observed in patients developing mature/immature hips postnatally. CONCLUSIONS: Prenatal diagnostics show promise for predicting infant hip development. Further research is warranted to validate correlation strength and clinical applicability.

Deciphering the pathogenic role of rare RAF1 heterozygous missense mutation in the late-presenting DDH.

Background: Developmental Dysplasia of the Hip (DDH) is a skeletal disorder where late-presenting forms often escape early diagnosis, leading to limb and pain in adults. The genetic basis of DDH is not fully understood despite known genetic predispositions. Methods: We employed Whole Genome Sequencing (WGS) to explore the genetic factors in late-presenting DDH in two unrelated families, supported by phenotypic analyses and in vitro validation. Results: In both cases, a novel de novo heterozygous missense mutation in RAF1 (c.193A>G [p.Lys65Glu]) was identified. This mutation impacted RAF1 protein structure and function, altering downstream signaling in the Ras/ERK pathway, as demonstrated by bioinformatics, molecular dynamics simulations, and in vitro validations. Conclusion: This study contributes to our understanding of the genetic factors involved in DDH by identifying a novel mutation in RAF1. The identification of the RAF1 mutation suggests a possible involvement of the Ras/ERK pathway in the pathogenesis of late-presenting DDH, indicating its potential role in skeletal development.

Total hip arthroplasty with porous tantalum trabecular metal pads in patients with Crowe IV developmental dysplasia of the hip: a midterm followup study.

PURPOSE: Crowe IV developmental dysplasia of the hip (DDH) is a catastrophic hip disease. Moreover, obtaining ideal clinical efficacy in conventional total hip arthroplasty (THA) is often difficult. In this study, we aimed to assess the mid-term clinical results of THA with porous tantalum trabecular metal (TM) pads for acetabular reconstruction in the treatment of Crowe IV DDH. METHODS: A cohort of 28 patients (32 hips) diagnosed with Crowe type IV DDH who underwent acetabular reconstruction during THA using TM pads with scheduled follow-up between 2011 and 2018, were included in this study. Eight cases were men and 24 were women, with a mean age of 48.4 years (range, 36-72 years) and a mean follow-up was 74.3 months (range, 42-132 months). All patients underwent acetabular reconstruction using TM pads and total hip replacement with subtrochanteric osteotomy. RESULTS: At the final follow-up, 28 hips (87.5%) demonstrated mild or no postoperative limping. The Harris Hip Score improved from 58.4 ± 10.6 preoperatively to 85.6 ± 8.9. The mean pain, stiffness, and function scores on the Western Ontario and McMaster University Osteoarthritis index were 86.5 ± 10.2, 87.3 ± 12.4 and 85.4 ± 11.6 respectively. The mean score of patient satisfaction was 90.4 ± 7.6. Additionally, the SF-12 physical summary score was 41.8 ± 5.6 and the SF-12 mental summary score was 51.6 ± 5.4. TM construct survivorship due to all-cause failure was 90.6% at 5 years with 3 hips at risk, 87.5% at 10 years with 4 hips at risk. The survivorship due to failure from aseptic loosening was 96.9% at 5 years with 1hips at risk and 93.75% at 10 years with 2 hips at risk. CONCLUSION: This study demonstrated satisfactory mid-term clinical and radiological results with the application of TM pads for acetabular reconstruction combined with THA in patients with Crowe IV DDH. TRIAL REGISTRATION NUMBER: ChiCTR1800014526, Date: 18/01/2018.

An in-depth analysis of young adults with osteonecrosis secondary to developmental dysplasia of the hip who underwent total hip arthroplasty.

BACKGROUND: Patients with osteonecrosis of the femoral head secondary to DDH frequently require total hip arthroplasty (THA), but it is not well understood which factors necessitate this requirement. We determined the incidence of THA in patients who have osteonecrosis secondary to DDH and factors associated with need for THA. METHODS: We included patients who received closed or open reductions between 1995 and 2005 with subsequent development of osteonecrosis. We determined osteonecrosis according to Bucholz and Ogden; osteoarthritis severity (Kellgren-Lawrence), subluxation (Shenton's line); neck-shaft angle; and acetabular dysplasia (centre-edge and Sharp angles). We also recorded the number of operations of the hip in childhood and reviewed case notes of patients who received THA to describe clinical findings prior to THA. We assessed the association between radiographic variables and the need for THA using univariate logistic regression. RESULTS: Of 140 patients (169 hips), 22 patients received 24 THA (14%) at a mean age of 21.3 ± 3.7 years. Associated with the need for THA were grade III osteonecrosis (OR 4.25; 95% CI 1.70-10.77; p = 0.0019), grade IV osteoarthritis (21.8; 7.55-68.11; p < 0.0001) and subluxation (8.22; 2.91-29.53; p = 0.0003). All patients who required THA reported at least 2 of: severe pain including at night, stiffness, and reduced mobility. Acetabular dysplasia and number of previous operations were not associated with the need for THA. CONCLUSIONS: We identified a 14% incidence of THA by age 34 years in patients with osteonecrosis secondary to DDH. Grade III osteonecrosis (global involvement femoral head and neck) was strongly associated with THA, emphasising the importance to avoid osteonecrosis when treating DDH.

Effects of lower limb length discrepancy on spinopelvic compensation following total hip arthroplasty in patients with developmental dysplasia of the hip.

BACKGROUND: Limited research has examined the impact of lower limb length discrepancy (LLLD) alteration on spinopelvic compensation in individuals with developmental dysplasia of the hip (DDH). This study aimed to investigate the effects of LLLD on spinopelvic compensation following total hip arthroplasty (THA) and elucidate the complex biomechanical adaptations in the spinopelvic structures. METHODS: A retrospective review of DDH patients undergoing THA from January 2014 to December 2021 categorized individuals with Crowe type I and II into the low dislocation group (LDG, n = 94) and those with Crowe type III and IV into the high dislocation group (HDG, n = 43). Demographic data, as well as preoperative, postoperative, and last follow-up imaging data, including lower limb length (LLL), sacral obliquity (SO), iliac obliquity (IO), hip obliquity (HO), Cobb angle, apical vertebral translation (AVT), and coronal decompensation (CD), were collected for analysis. RESULTS: Patients in the LDG had a significantly higher surgical age and shorter disease duration (P<0.05). In LDG, patients exhibited substantial postoperative reductions in LLLD, SO, IO, and HO (P<0.05), while Cobb Angle, AVT, and CD showed no statistically significant changes (P>0.05). The variation in LLLD correlated significantly with the variations in SO, IO, and HO (P<0.05). Postoperative outcomes in the HDG demonstrated marked decreases in LLLD, SO, IO, HO, and CD (P<0.05), with no significant change in Cobb angle and AVT (P>0.05). The variation in LLLD correlated significantly with the variations in SO, IO, HO, and CD (P<0.05). CONCLUSIONS: THA effectively reduces LLLD in patients with DDH, and the variation in LLLD correlates meaningfully with the recovery of spinopelvic compensatory mechanisms.

Outcomes following medial open reduction in infants aged ≤6 months with developmental dysplasia of the hip.

Aim: To evaluate mid-long term radiological outcomes following early medial approach open reduction (MAOR) performed for developmental dysplasia of the hip (DDH) in infants aged ≤6 months old at time of surgery, specifically incidence of clinically significant avascular necrosis (AVN), Severin outcomes and rates of further surgery. Methods: This is a single centre retrospective study of patients treated from 1999 to 2017. Only infants aged ≤6 months old at time of MAOR, and aged at least 6 years old at latest follow-up were included (minimum 5.5 years follow-up). Data was collected from electronic healthcare records and serial radiographs reviewed to assess outcomes. AVN was classified according to Kalamchi and MacEwen, with types 2-4 considered clinically significant. Severin classes I (excellent) and II (good) were considered satisfactory outcomes, and classes III + considered unsatisfactory. Results: MAOR was performed on 48 hips in 44 patients. Mean age at time of surgery was 4 months (SD 1.4, range 2-6), with mean follow-up of 9.8 years (SD 2.7, range 6.2-16.2). Clinically significant AVN developed in 9/48 hips (19 %), all of which were type 2. Only 1/48 hips (2 %) required a subsequent pelvic osteotomy due to residual dysplasia with subluxation at 2 years post MAOR. At final follow-up, 81 % of patients had excellent or good radiological outcomes (Severin I/II). No statistically significant predictors for developing AVN, including age and presence of ossific nucleus, were identified. Conclusion: Early MAOR in infants aged ≤6 months was associated with a very low rate of significant residual dysplasia requiring further surgery, yet was not associated with unacceptable rates or severe forms of AVN. We therefore recommend MAOR is performed early to optimise acetabular remodelling potential and minimise the need for concurrent or subsequent bony procedures.

Treatment of developmental hip dysplasia with manual therapy following Pavlik harness failure: a case report with long-term follow-up.

BACKGROUND: Developmental dysplasia of the hip (DDH) is a common musculoskeletal disorder in newborns, ranging from mild dysplasia to complete dislocation. Early detection and intervention are crucial for managing DDH. However, in some cases, standard orthopedic treatments such as the Pavlik harness fail, and alternative approaches are needed. Our study explores the possibility that manual therapy, specifically the Mézières-Bertelè Method (MBM), could be beneficial in cases of DDH that are resistant to conventional treatments. CASE DESCRIPTION: We present a case of a 20-month-old female who had been suffering from persistent DDH (Graf's type IIIC on the left), pain and limping, despite previous conventional treatments, including the Pavlik harness. The patient received daily MBM sessions for six months, followed by maintenance sessions every two months. OUTCOMES: After undergoing the MBM treatment, the patient showed clinical improvements, such as normal neuromotor development and restored hip joint parameters. We observed normal walking and running abilities, and X-ray parameters returned to normal levels. The patient sustained positive outcomes during long-term follow-up until the age of 7. CONCLUSION: The MBM manual therapy was used to treat a challenging case of DDH resistant to conventional treatment. This case report suggests a possible correlation between manual therapy and improved outcomes in resistant DDH and highlights the potential relevance of addressing the inherent musculoskeletal components of the condition.

Community Awareness About Developmental Dysplasia of the Hip (DDH) in the Western and Southern Regions of Saudi Arabia.

BACKGROUND: Developmental dysplasia of the hip (DDH) is a disorder in which the hip joint does not develop normally in the pediatric age group. It is caused by a confluence of hereditary and environmental factors. We aimed to examine knowledge and awareness of DDH among the general population of the southern and western regions of Saudi Arabia. METHODOLOGY: A cross-sectional survey-based study was conducted in the western and southern regions of Saudi Arabia. This study included adult male and female participants above 18 years of age. Data were collected using a validated electronic questionnaire that was disseminated via social media platforms. All data were analyzed using IBM SPSS Statistics for Windows, Version 23.0 (IBM Corp., Armonk, NY). RESULTS: In this study, 1,232 participants were surveyed in Saudi Arabia. The majority were between 21 and 30 years old (663, 53.8%), unmarried (690, 56%), and had a baccalaureate or diploma certificate (886, 71.9%). Regarding knowledge of DDH, 86.4% of participants had poor knowledge of the causes of DDH, and 740 (60%) had poor overall knowledge of DDH. However, 492 (40%) participants had good knowledge. Respondents with a higher monthly income, those who were mothers, and those who obtained information from social media had a better awareness level. Concerning treatment, 531 (43.1%) participants were unsure about the best treatment for DDH, and 850 (69%) believed that early treatment was better. CONCLUSIONS: According to our literature, DDH is highly prevalent among Saudi populations. However, our findings indicate that the majority of the Saudi population residing in the western and southern regions of Saudi Arabia lacks basic knowledge of DDH. All capable facilities, such as medical schools, hospitals, and primary healthcare centers, must impart cultural education about DDH to address this awareness gap.

[Hip joint biomechanical analysis of the acetabular anatomical reconstruction and nonanatomical reconstruction in total hip arthroplasty for Crowe type â ¢ developmental dysplasia of the hip by finite element method].

OBJECTIVE: To analyze the hip joint biomechanics of the acetabular anatomical reconstruction and nonanatomical reconstruction in total hip arthroplasty (THA) for Crowe type Ⅲ developmental dysplasia of the hip (DDH) by finite element method, which provided theoretical foundation and experimental basis for the anatomical acetabular reconstruction during THA in clinical practice. METHODS: One patient with left end-stage hip arthritis secondary to Crowe type Ⅲ DDH was selected in this study, who underwent total hip arthroplasty in the orthopedic department of the First Affiliated Hospital of Bengbu Medical College in April 2020. This patient was female, 57 years old. The preoperative and postoperative three dimentional CT scan of the patient's pelvis were performed. Fourteen acetabular cup models with different anteversion, inclination and rotation center height were established in Mimics and 3-Matic software. The boundary and load conditions were set in Abaqus software. The Von Mises and stress distribution of the hip joint were calculated and observed. RESULTS: In the Crowe type Ⅲ DDH THA, if the hip rotation center was restored anatomically and the acetabular cup's inclination was set as 40°, the cup's anteversion varied from 5° to 25°, the lowest Von Mises value of acetabular cup and polyethylene liner occured in 20°anteversioin;if the hip rotation center was restored anatomically and the acetabular cup's anteversion was set as 15°, the cup's inclination varied from 35° to 55°, the lowest Von Mises value of acetabular cup and polyethylene liner occured in 35° inclination;if the acetabular cup's anteversion and inclination were set as 15°and 40°respectively, the up migration of hip rotaion center varied from 0 mm to 20 mm, the lowest Von Mises value of acetabular cup and polyethylene liner occured in 10 mm up migration. In all fourteen models, the Von Mises value of the acetabulum, acetabulum cup and polyethylene liner were lowest when the acetabular cup's anteversion and inlcination were 15°, 35° respectively, as well as the rotation center was restored anatomically. CONCLUSION: In total hip arthroplasty for Crowe type Ⅲ DDH, the anatomical restoration of hip rotation center with 15° anteversion and 35° inclination of the acetabular cup are suggested, bone graft above the acetabular cup and additional screws are recommended simultaneously to further reduce the Von Mises of hip joint.

Comparison Static and Dynamic Ultrasound Techniques of DDH: The Role of the Patient's Position.

Objectives: The ultrasound examination of the hip joint is performed in the static (Graf) technique in the lateral recumbent position and in the dynamic technique in the supine position. This study compares the two static and dynamic techniques and assesses the role of the patient's position in the examination of DDH. Methods: This cross-sectional study was conducted in 2020-2021 at Akbar Hospital, Mashhad University of Medical Sciences, Iran. 126 patients suspected of having DDH (199 hip) infants were enrolled in the study. All ultrasound examinations were performed with two static and dynamic techniques by a pediatric radiologist. Results: In the static and dynamic ultrasound examinations, the average alpha angle was 51.57 ± 6.41 degrees, and 53.41 ± 6.94 degrees, respectively. These changes were not statistically significant (P = 0.312). The relationship and agreement between instability with dynamic technique and instability with static technique (IIC unstable, D, III, and IV) were investigated. Significant agreement (Kappa=0.77 (95% CI: 0.66-0.87) with excellent clinical significance was obtained between the two ultrasound examination method. Also, in terms of DDH types in the static method with instability types in the dynamic method, a substantial agreement was found between the two examination methods (Kappa =0.67; (95% CI: 0.59-0.75) with good clinical significance. Conclusion: In the ultrasound examination of DDH with static and dynamic techniques, the change in the alpha angle was not statistically significant. Therefore, the hand of the radiologist is open in measuring alpha angles and there is no need to emphasize a specific position. The type of DDH in the static technique completely corresponded to the type of stability or instability in the dynamic technique.

The role of the cartilaginous to osseous acetabular angle ratio in children with developmental dysplasia of the hip.

Purpose: This study aims to demonstrate the use of the cartilaginous to osseous acetabular angle ratio (AAR) in surgical decision-making for hip dysplasia. Methods: Data were collected from patients who underwent an MRI of the hip after conservative treatment for developmental dysplasia of the hip between August 2019 and 2022. The data included demographic information as well as an anteroposterior pelvic radiograph. The osseous acetabular index (OAI) was measured using x-ray, while the cartilaginous acetabular index (CAI) and the cartilaginous acetabulum head index (CAHI) were measured using MRI. The square of the CAI to OAI, AAR, was calculated. The patients in the residual hip dysplasia (RHD) group were categorized as having an OAI above 20°. During the postoperative follow-up, we evaluated the patients in this group who underwent Bernese triple pelvic osteotomy. Data on surgical patients with an observation period that exceeded 1 year were collected and analyzed. The distribution of the AAR among the different groups was analyzed. A receiver operating characteristic (ROC) predictive model was constructed using the AAR of the patients in the normal and surgical groups to evaluate the need for surgery. Results: It was found that there was a significant difference in the OAI, CAI, CAHI, and AAR between the RHD group (OAI 26.15 ± 3.90°, CAI 11.71 ± 4.70°, CAHI 79.75 ± 6.27%, and AAR 5.88 ± 4.24) and the control group patients (OAI 16.77 ± 5.39°, CAI 6.16 ± 3.13°, CAHI 85.05 ± 4.91%, and AAR 2.71 ± 2.08) (p < 0.001). A total of 93.5% of the control group patients had an AAR ≤5, while only 6.5% had an AAR >5. The results of postoperative imaging follow-up were "excellent" in 52 patients and "good" in 3, while the functional follow-up results were excellent in 53 and good in 2. In 15 patients, the observation period exceeded 1 year. The mean observation period was 633.1 ± 259.6 days and the preoperative CAHI was 71.7 ± 4.8%. Of the patients with an AAR >5, a substantial 94.8% (55/58) of them were reported to have undergone surgery, while all patients with an AAR less than or equal to 5 did not undergo surgery (91/91). Based on the ROC, a cutoff value of 5.09 was identified for the need for surgery in children with RHD. Conclusions: A surgical decision for residual hip dysplasia can be based on the AAR. An AAR >5 may be a potential indicator for surgical intervention in patients with RHD.