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.

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.

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 (NIH) Quality Assessment tool. Various outcomes including revision rates, leg length discrepancy (LLD), Harris Hip Score (HHS), and complications like periprosthetic joint infections (PJI), dislocations, and nerve injuries were analyzed. A random effects model was employed for statistical analysis, with sensitivity analysis and meta-regression 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 HHS and reductions in LLD post-THA. However, notable challenges were noted, including a 10.7% rate of intraoperative fractures, a 1.8% PJI rate, and a 5.8% dislocation rate. Osteolysis and aseptic loosening revisions were observed in 9.1 and 8% of cases, respectively. Heterotopic ossification (HO) occurred in 11.1% of patients. Nerve injury was reported in 4.2% of cases. With the use of meta-regression, some factors for observed heterogeneity were identified. CONCLUSION: Total hip arthroplasty in Crowe type IV DDH patients presents notable challenges, but can lead to substantial long-term improvements in patient-reported outcomes.

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.

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.

[Development and Application of Deep Learning-Based Model for Quality Control of Children Pelvic X-Ray Images].

Objective: A deep learning-based method for evaluating the quality of pediatric pelvic X-ray images is proposed to construct a diagnostic model and verify its clinical feasibility. Methods: Three thousand two hundred and forty-seven children with anteroposteric pelvic radiographs are retrospectively collected and randomly divided into training datasets, validation datasets and test datasets. Artificial intelligence model is conducted to evaluate the reliability of quality control model. Results: The diagnostic accuracy, area under ROC curve, sensitivity and specificity of the model are 99.4%, 0.993, 98.6% and 100.0%, respectively. The 95% consistency limit of the pelvic tilt index of the model is -0.052-0.072. The 95% consistency threshold of pelvic rotation index is -0.088-0.055. Conclusion: This is the first attempt to apply AI algorithm to the quality assessment of children's pelvic radiographs, and has significantly improved the diagnosis and treatment status of DDH in children.

A novel intraoperative acetabular reaming center locating method in total hip arthroplasty for Crowe type IV developmental dysplasia of the hip: a retrospective cohort study.

PURPOSE: Although the principles of hip reconstruction are consistent, due to lack of reliable anatomical landmarks, how to decide the acetabular cup reaming centre intraoperatively in Crowe IV patients with developmental dysplasia of the hip (DDH) remains unclear. This study aims to address this question. METHODS: Fifty-eight Crowe IV patients were enrolled from 2017 to 2019. By examining our previous clinical data, we analyzed the anatomical morphology of Crowe IV acetabulum and proposed a method of locating intraoperative reaming centering for implantation of a standard-sized acetabular cup, which is the upper two thirds of the posterior border of the true acetabulum. All patients included in this study were reamed according to this method. The average postoperative follow-up was 4.1 years (3-5 years). The position of the centre of rotation (COR), cup coverage (CC), and optimal range of joint motion (ROM) were examined by 3D computer simulation measurement. Postoperative complications and hip Harris score were collected and analyzed. RESULTS: The morphology of the type IV DDH true acetabulum was mostly triangular. The intraoperative reaming centre were centered on the upper two thirds of the posterior border of the true acetabulum. The postoperative 3D CC was 80.20% ± 7.63% (64.68-90.24%, 44-48-mm cup size). The patients' mean Harris score improved from 39.7 ± 20.4 preoperatively to 91.5 ± 8.12 at the last follow-up. CONCLUSION: Our study demonstrated that satisfactory CC and clinical results could be achieved by implanting a standard-sized cup with the reaming centre on the upper two thirds of the posterior border of the true acetabulum.

Transinguinal Ultrasound versus Magnetic Resonance in Spica Cast after Closed Reduction of Unstable Hips in DDH.

BACKGROUND: During the treatment of unstable hips in developmental hip dysplasia (DDH), the position of the femoral head must be assessed in spica cast (SC) after reduction. A transinguinal sonographic technique (TIT) to the hip joint has been previously described in the literature. The aim of this study is to evaluate the agreement among TIT and MR to identify hip reduction. METHODS: From 2016 to 2019, 14 consecutive newborns (10 female, 4 males) with a mean age of 2.97 ± 1.29 months were treated with closed reduction in SC. A total of 4/14 children had bilateral unstable DDH. Out of 18 hips, there were 8 hips type IV and 10 hips type IIIA, according to Graf. SC were changed monthly and hips were checked both with TIT and MR, looking for persistent dislocation. RESULTS: Overall, a mean of 2.61 SC/hip (mode = 3) was accomplished, accounting for 47 procedures, with 46 reduced hips and 1 dislocated hip: TIT and MR always agreed on the same result (47/47; Cohen k = 1, CI95 1.00 to 1.00). CONCLUSIONS: The inguinal ultrasound technique described by van Douveren showed perfect agreement with MR and might be considered a reliable alternative to check the position of the femoral head during the conservative treatment of hip dysplasia in spica cast.

Pediatric Hip Dysplasia Surgery Outcomes by Pediatric Versus Nonpediatric Orthopedists.

Objectives Developmental dysplasia of the hip (DDH) encompasses a spectrum of abnormalities in the immature hip. Surgical intervention is indicated if conservative management fails. Despite the increased supply of pediatric orthopedic surgeons (POSs) over the last few decades, there continues to be a maldistribution of surgeons. The purpose of this study is to determine outcomes following surgical management of hip dysplasia by POSs compared to non-pediatric orthopedic surgeons. Methods Pediatric patients who underwent surgical treatment for hip dysplasia from 2012 to 2019 were identified using a large national database. Patient demographics, comorbidities, and postoperative complications were compared by pediatric versus nonpediatric-trained orthopedic surgeons. Bivariate and multivariable regression analyses were performed. Results Of the 10,780 pediatric patients who underwent hip dysplasia surgery, 10,206 patients (94.7%) were operated on by a POS, whereas 574 (5.3%) were operated on by a non-pediatric orthopedic surgeon. POSs were more likely to operate on patients with a higher American Society of Anesthesiologists class (p<0.001) and those with a greater number of medical comorbidities, including cardiac (p=0.001), gastrointestinal (p=0.017), and neurological (p<0.001). Following analysis using multivariable regression models to control for patient baseline characteristics, there were no differences in any postoperative complications between patients treated by pediatric-trained and nonpediatric-trained orthopedic surgeons. Conclusions Compared to non-pediatric orthopedic surgeons, POSs were more likely to operate on younger patients with increased medical comorbidities. However, there were no differences in postoperative complications following surgical management for DDH in patients treated by nonpediatric and pediatric orthopedic surgeons.

Long-term outcomes of total hip arthroplasty in patients with developmental dysplasia of the hip: a minimum 21-year follow-up.

PURPOSE: Early osteoarthritis (OA) due to developmental dysplasia of the hip (DDH) is a known indication for total hip arthroplasty (THA). Though screening tools and joint-preserving procedures have been established successfully, there still is a relevant number of patients suffering DDH. Due to the lack of long-term outcome studies, we like to close this gap and present the results of a highly specialized center. METHODS: The study included 126 patients, who were treated in our institution with primary THA for DDH between January 1997 and December 2000. At the time of final follow-up, at a mean of 23 years postoperatively, 110 patients (121 hips) were clinically evaluated using the Harris-Hip Score. In addition, complication and surgical revision rates were assessed. We collected surgery-related data like implant choice and special surgical features such as autologous acetabular reconstruction or femoral osteotomies. Additionally, the severity of preoperative DDH was measured radiographically according to Crowe classification. RESULTS: There were 91 female (83%) and 19 male (17%) patients with an average age of 51 ± 9.5 years (range 21-65) included. Mean follow-up was 23 ± 1.3 years (21-25), with a minimum of 21 years being necessary for inclusion. Using revision for any indication as primary endpoint, the Kaplan-Meier survivorship was 98.3% at 10 years and 81.8% at final follow-up. The overall revision rate was 18% (22 cases), which were split up as follows: 20 (17%) implant failures (loosened or broken components), one (1%) periprosthetic infection and one (1%) periprosthetic fracture. Regarding complications, we observed nine (7%) dislocations and one case (1%) with severe heterotopic ossification that required surgical excision. The mean Harris-Hip score at latest follow-up was 78 ± 14 points (32-95). CONCLUSIONS: Though implants and surgical techniques have improved over time, our results suggest THA in patients suffering DDH to be seriously challenging with relatively high overall complications in long-term observation and fair clinical outcome after 21 years postoperatively. There is evidence that prior osteotomy might be associated with a higher revision rate.

Radiological long-term follow-up up to 12 years of initially ultrasound unstable hip types D, III and IV after treatment with the Tübingen splint worn as a plaster.

INTRODUCTION: The treatment of ultrasound unstable hips with the Tübingen splint is currently under discussion. However, there is a lack of long-term follow-up data. This study presents to the best of our knowledge first radiological mid-term to long-term data of the successful initial treatment with the Tübingen splint of ultrasound unstable hips. MATERIALS AND METHODS: From 2002 to 2022 the treatment of ultrasound unstable hips type D, III and IV (age ≤ 6 weeks, no severe limitation of abduction) with the Tübingen splint worn as a plaster is evaluated. Based on data derived from routine X-rays during the follow-up period, a radiological follow-up (FU) analysis until the age of 12 years was performed. The acetabular index (ACI) and center-edge angle (CEA) were measured and classified according to Tönnis as normal findings (NF), slightly (sliD) or severely dysplastic (sevD). RESULTS: 193 of 201 (95.5%) unstable hips could be successfully treated showing normal findings with an alpha angle > 65°. The few patients showing treatment failures were successfully treated applying a Fettweis plaster (human position) under anesthesia. The radiological FU of 38 hips showed a favorable trend with increase of normal findings from 52.8% to 81.1% and decrease of 38.9% to 19.9% of sliD respectively 8.3% to 0% of sevD hips. The analysis of avascular necrosis of the femoral head showed 2 cases (5.3%) of grade 1 according to Kalamchi and McEwen, which were improving over time in the further course. CONCLUSIONS: The Tübingen splint as alternative to replace a plaster has proven a successful therapeutic option for ultrasound unstable hips type D, III and IV with favorable and over time improving radiological parameter up to the age of 12 years.

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

AIMS: We investigated the prevalence of late developmental dysplasia of the hip (DDH), abduction bracing treatment, and surgical procedures performed following the implementation of universal ultrasound screening versus selective ultrasound screening programmes. METHODS: A systematic search of PubMed, Embase, The Cochrane Library, OrthoSearch, and Web of Science from the date of inception of each database until 27 March 2022 was performed. The primary outcome of interest was the prevalence of late detection of DDH, diagnosed after three months. Secondary outcomes of interest were the prevalence of abduction bracing treatment and surgical procedures performed in childhood for dysplasia. Only studies describing the primary outcome of interest were included. RESULTS: A total of 31 studies were identified, of which 13 described universal screening and 20 described selective screening. Two studies described both. The prevalence of late DDH was 0.10 per 1,000 live births (95% confidence interval (CI) 0.00 to 0.39) in the universal screening group and 0.45 per 1,000 live births (95% CI 0.31 to 0.61) in the selective screening group. Abduction bracing treatment was performed on 55.54 per 1,000 live births (95% CI 24.46 to 98.15) in the universal screening group versus 0.48 per 1,000 live births (95% CI 0.07 to 1.13) in the selective screening group. Both the universal and selective screening groups had a similar prevalence of surgical procedures in childhood for dysplasia being performed (0.48 (95% CI 0.32 to 0.63) vs 0.49 (95% CI 0.31 to 0.71) per 1,000 live births, respectively). CONCLUSION: Universal screening showed a trend towards lower prevalence of late DDH compared to selective screening. However, it was also associated with a significant increase in the prevalence of abduction bracing without a significant reduction in the prevalence of surgical procedures in childhood for dysplasia being performed. High-quality studies comparing both treatment methods are required, in addition to studies into the natural history of missed DDH.Cite this article: Bone Joint J 2023;105-B(2):198-208.

MRI assessment of femoral head docking following closed reduction of developmental dysplasia of the hip.

AIMS: Eccentric reductions may become concentric through femoral head 'docking' (FHD) following closed reduction (CR) for developmental dysplasia of the hip (DDH). However, changes regarding position and morphology through FHD are not well understood. We aimed to assess these changes using serial MRI. METHODS: We reviewed 103 patients with DDH successfully treated by CR and spica casting in a single institution between January 2016 and December 2020. MRI was routinely performed immediately after CR and at the end of each cast. Using MRI, we described the labrum-acetabular cartilage complex (LACC) morphology, and measured the femoral head to triradiate cartilage distance (FTD) on the midcoronal section. A total of 13 hips with initial complete reduction (i.e. FTD < 1 mm) and ten hips with incomplete MRI follow-up were excluded. A total of 86 patients (92 hips) with a FTD > 1 mm were included in the analysis. RESULTS: At the end of the first cast period, 73 hips (79.3%) had a FTD < 1 mm. Multiple regression analysis showed that FTD (p = 0.011) and immobilization duration (p = 0.028) were associated with complete reduction. At the end of the second cast period, all 92 hips achieved complete reduction. The LACC on initial MRI was inverted in 69 hips (75.0%), partly inverted in 16 hips (17.4%), and everted in seven hips (7.6%). The LACC became everted-congruent in 45 hips (48.9%) and 92 hips (100%) at the end of the first and second cast period, respectively. However, a residual inverted labrum was present in 50/85 hips (58.8%) with an initial inverted or partly inverted LACC. CONCLUSION: An eccentric reduction can become concentric after complete reduction and LACC remodelling following CR for DDH. Varying immobilization durations were required for achieving complete reduction. A residual inverted labrum was present in more than half of all hips after LACC remodelling.Cite this article: Bone Joint J 2023;105-B(2):140-147.

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

AIMS: A national screening programme has existed in the UK for the diagnosis of developmental dysplasia of the hip (DDH) since 1969. However, every aspect of screening and treatment remains controversial. Screening programmes throughout the world vary enormously, and in the UK there is significant variation in screening practice and treatment pathways. We report the results of an attempt by the British Society for Children's Orthopaedic Surgery (BSCOS) to identify a nationwide consensus for the management of DDH in order to unify treatment and suggest an approach for screening. METHODS: A Delphi consensus study was performed among the membership of BSCOS. Statements were generated by a steering group regarding aspects of the management of DDH in children aged under three months, namely screening and surveillance (15 questions), the technique of ultrasound scanning (eight questions), the initiation of treatment (19 questions), care during treatment with a splint (ten questions), and on quality, governance, and research (eight questions). A two-round Delphi process was used and a consensus document was produced at the final meeting of the steering group. RESULTS: A total of 60 statements were graded by 128 clinicians in the first round and 132 in the second round. Consensus was reached on 30 out of 60 statements in the first round and an additional 12 in the seond. This was summarized in a consensus statement and distilled into a flowchart to guide clinical practice. CONCLUSION: We identified agreement in an area of medicine that has a long history of controversy and varied practice. None of the areas of consensus are based on high-quality evidence. This document is thus a framework to guide clinical practice and on which high-quality clinical trials can be developed.Cite this article: Bone Joint J 2023;105-B(2):209-214.

Developmental retardation of femoral head size and femoral head ossification in mild and severe developmental dysplasia of the hip in infants: a preliminary cross-sectional study based on ultrasound images.

Background: For infants up to 6 months, ultrasound (US) screening of developmental dysplasia of the hip (DDH) is recommended. This cross-sectional study investigated the developmental data of femoral head size and femoral head ossification in mature infant hips and the impact of mild and severe DDH on femoral head development based on US images. Methods: We reviewed all hip US studies performed from January 2018 to December 2019 to evaluate DDH in infants younger than 6 months at West China Hospital, Sichuan University. The femoral head diameter (FHD) and femoral head ossification center type of each hip were recorded. A total of 1,037 normal participants with 2,074 mature hips and 367 DDH participants with 456 dysplastic hips were included in this study. Results: For normal mature hips (Graf I), the FHD of mature male hips was significantly larger than that of female hips from the age of 2 months to 6 months (all P values <0.01), and the femoral head ossification center of males occurred significantly later than that of females at the same age from 3 months to 6 months (all P values <0.05). Compared with the matched mature hips, the FHDs of Graf IIa (-), IIb, IIc, and D, III or IV hips were significantly smaller (1.64 vs. 1.72 cm, 1.75 vs. 1.79 cm, 1.65 vs. 1.73 cm, 1.51 vs. 1.71 cm, respectively; all P values <0.05), and the occurrence of the femoral head ossification center was delayed in Graf IIa (-) and D, III or IV hips (both P values <0.05). However, no significant developmental retardation of the femoral head was observed in Graf IIa (+) hips. Conclusions: We identified a relatively normal range for the development of infants' hips from 1 month old to 6 months old and found significant developmental retardation of the femoral head in Graf IIa (-), IIb, IIc, and D, III or IV hips. This is a preliminary study of the developmental impact of DDH on the femoral head, and we will continue the follow-up study after treatment.

Smart Hip Ultrasound Technology in Screening for Infant Developmental Dysplasia of the Hip / 中山大学学报(医学科学版)

ObjectiveTo develop a deep learning system for early ultrasound screening of developmental dysplasia of the hip （DDH）， a new smart-hip ultrasound technique （S-hip）， and to validate its clinical application. MethodsWe selected 11，100 annotated and reviewed coronal ultrasound images of infant hips between November 2021 and August 2022， 8，100 of which were used for the training set and 3，000 for the test set， to build a S-hip deep learning system. To verify the consistency between the automated measurement by S-hip and the manual measurements by sonographers， 174 standard coronal ultrasound images of 87 infants' bilateral hips were acquired， then α angle， β angle and femoral head coverage （FHC） were measured by S-hip， an ultrasound expert and a resident. The measurement data and the time required for the measurements were recorded and statistically analyzed. Another 100 standard coronal ultrasound images of the hips were randomly selected and measured twice respectively by the ultrasound expert and resident to assess the intra-sonographer repeatability. ResultsThe intraclass correlation coefficient （ICC） （95% CI） values of α angle， β angle and FHC results measured by S-hip and ultrasound expert were 0.799 （0.738， 0.847）， 0.798 （0.737， 0.846） and 0.934 （0.954， 0.975）， respectively. Those values measured by the ultrasound expert and resident were 0.725 （0.645， 0.789）， 0.674 （0.583， 0.748） and 0.931 （0.908， 0.949）， respectively. The mean absolute errors （MAE） of α angle， β angle and FHC results between measurements by S-hip and ultrasound expert were 2.69 °， 4.43 ° and 2.47%， respectively. The time required for measurements by S-hip， ultrasound expert and resident was （1.59±0.36） s， （18.76±2.23） s and （19.45±2.76） s， respectively. The automated measurement by S-hip cost much shorter time than the manual measurements by sonographers and the difference was statistically significant （P<0.001）. The ICC （95% CI） values of α angle， β angle and FHC results between two measurements by the ultrasound expert were 0.943 （0.916， 0.961）， 0.959 （0.940， 0.972）， and 0.981 （0.971， 0.987）， respectively. Those values by the ultrasound resident were 0.884 （0.833， 0.921）， 0.921 （0.884， 0.946）， and 0.962 （0.944， 0.974）. ConclusionThe S-hip based on a deep learning system is a highly reliable automated technique to accurately measure α angle， β angle and FHC. Compared with ultrasound residents， S-hip allows for a more simplified and significantly quicker measurement， which may enhance the widespread use of hip ultrasound screening in infants.

Normal variation of infant hip development : patterns revealed by 3D ultrasound.

AIMS: Studies of infant hip development to date have been limited by considering only the changes in appearance of a single ultrasound slice (Graf's standard plane). We used 3D ultrasound (3DUS) to establish maturation curves of normal infant hip development, quantifying variation by age, sex, side, and anteroposterior location in the hip. METHODS: We analyzed 3DUS scans of 519 infants (mean age 64 days (6 to 111 days)) presenting at a tertiary children's hospital for suspicion of developmental dysplasia of the hip (DDH). Hips that did not require ultrasound follow-up or treatment were classified as 'typically developing'. We calculated traditional DDH indices like α angle (αSP), femoral head coverage (FHCSP), and several novel indices from 3DUS like the acetabular contact angle (ACA) and osculating circle radius (OCR) using custom software. RESULTS: α angle, FHC, and ACA indices increased and OCR decreased significantly by age in the first four months, mean αSP rose from 62.2° (SD 5.7°) to 67.3° (SD 5.2°) (p < 0.001) in one- to eight- and nine- to 16-week-old infants, respectively. Mean αSP and mean FHCSP were significantly, but only slightly, lower in females than in males. There was no statistically significant difference in DDH indices observed between left and right hip. All 3DUS indices varied significantly between anterior and posterior section of the hip. Mean 3D indices of α angle and FHC were significantly lower anteriorly than posteriorly: αAnt = 58.2° (SD 6.1°), αPost = 63.8° (SD 6.3°) (p < 0.001), FHCAnt = 43.0 (SD 7.4), and FHCPost = 55.4° (SD 11.2°) (p < 0.001). Acetabular rounding measured byOCR indices was significantly greater in the anterior section of the hip (p < 0.001). CONCLUSION: We used 3DUS to show that hip shape and normal growth pattern vary significantly between anterior and posterior regions, by magnitudes similar to age-related changes. This highlights the need for careful selection of the Graf plane during 2D ultrasound examination. Whole-joint evaluation by obtaining either 3DUS or manual 'sweep' video images provides more comprehensive DDH assessment.Cite this article: Bone Jt Open 2022;3(11):913-923.

Testing of an Ultrasound-Limited Imaging Protocol for Pavlik harness Supervision (TULIPPS) in developmental dysplasia of the hip: a randomized controlled trial.

AIMS: There is no consensus regarding optimum timing and frequency of ultrasound (US) for monitoring response to Pavlik harness (PH) treatment in developmental dysplasia of the hip (DDH). The purpose of our study was to determine if a limited-frequency hip US assessment had an adverse effect on treatment outcomes compared to traditional comprehensive US monitoring. METHODS: This study was a single-centre noninferiority randomized controlled trial. Infants aged under six months whose hips were reduced and centred in the harness at initiation of treatment (stable dysplastic or subluxable), or initially decentred (subluxated or dislocated) but reduced and centred within four weeks of PH treatment, were randomized to our current standard US monitoring protocol (every clinic visit) or to a limited-frequency US protocol (US only at end of treatment). Groups were compared based on α angle and femoral head coverage at the end of PH treatment, acetabular indices, and International Hip Dysplasia Institute (IHDI) grade on one-year follow-up radiographs. RESULTS: Overall, 100 patients were included; 42 patients completed the standard protocol (SP) and 40 completed the limited protocol (LP). There was no significant difference in mean right α angle at the end of treatment (SP 70.0° (SD 3.2°) ; LP 68.7° (SD 2.9°); p = 0.033), nor on the left (SP 69.0° (SD 3.5°); LP 68.1° (SD 3.3°); p = 0.128). There was no significant difference in mean right acetabular index at follow-up (SP 23.1° (SD 4.3°); LP 22.0° (SD 4.1°); p = 0.129), nor on the left (SP 23.3° (SD 4.2°); LP 22.8° (SD 3.9°); p = 0.284). All hips had femoral head coverage of > 50% at end of treatment, and all were IHDI grade 1 at follow-up. In addition, the LP group underwent a 60% reduction in US use once stable. CONCLUSION: Our study supports reducing the frequency of US assessment during PH treatment of DDH once a hip is reduced and centred.Cite this article: Bone Joint J 2022;104-B(9):1081-1088.

The incidence and risk factors for stress fracture following periacetabular osteotomy.

AIMS: The aims of this study were to characterize the incidence and risk factors associated with stress fractures following periacetabular osteotomy, and to determine their effect on osteotomy union. METHODS: We retrospectively reviewed all periacetabular osteotomies (PAOs) performed for developmental dysplasia of the hip (DDH) at one institution over a six-year period between 2012 and 2017. Perioperative factors were recorded, and included demographic and surgical data. Postoperatively, patients were followed for a minimum of one year with anteroposterior and false profile radiographs of the pelvis to monitor for evidence of stress fracture and union of osteotomies. We characterized the incidence and locations of stress fractures, and used univariate and multivariable analysis to identify factors predictive of stress fracture and the association of stress fracture on osteotomy union. RESULTS: A total of 331 patients underwent PAO during the study period with 56 (15.4%) stress fractures: 46 fractures of the retroacetabular posterior column, five cases of ischiopubic stress fracture, and five cases of concurrent ischiopubic and retroacetabular stress fractures. Overall, 86% (48/56) healed without intervention. Univariate analysis revealed that stress fractures occurred more frequently in females (p = 0.040), older patients (mean age 27.6 years (SD 8.4) vs 23.8 (SD 9.0); p = 0.003), and most often with the use of the broad Mast chisel (28.5%; p < 0.001). Multivariable analysis revealed that increasing age (odds ratio (OR) 1.04; 95% CI 1.01 to 1.07; p = 0.028) and use of the broad Mast chisel (OR 5.1 (95% CI 1.3 to 19.0) compared to narrow Ganz chisel; p = 0.038) and surgeon (p = 0.043) were associated with increased risk of stress fracture. Patients with stress fractures were less likely to have healed osteotomies after one-year follow-up (76% vs 96%; p < 0.001). CONCLUSION: Stress fracture of the posterior column may be an under-recognized complication following PAO, and the rate may be influenced by surgical technique. Consideration should be given to using a narrow chisel during the ischial cut to reduce the risk of stress propagation through the posterior column.Cite this article: Bone Joint J 2022;104-B(9):1017-1024.