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Purpose: To clarify the morphological factors of the pelvis in patients with developmental dysplasia of the hip (DDH), three-dimensional (3D) pelvic morphology was analyzed using a template-fitting technique., Methods: Three-dimensional pelvic data of 50 patients with DDH (DDH group) and 3D pelvic data of 50 patients without obvious pelvic deformity (Normal group) were used. All patients were female. A template model was created by averaging the normal pelvises into a symmetrical and isotropic mesh. Next, 100 homologous models were generated by fitting the pelvic data of each group of patients to the template model. Principal component analysis was performed on the coordinates of each vertex (15,235 vertices) of the pelvic homologous model. In addition, a receiver-operating characteristic (ROC) curve was calculated from the sensitivity of DDH positivity for each principal component, and principal components for which the area under the curve was significantly large were extracted (p<0.05). Finally, which components of the pelvic morphology frequently seen in DDH patients are related to these extracted principal components was evaluated., Results: The first, third, and sixth principal components showed significantly larger areas under the ROC curves. The morphology indicated by the first principal component was associated with a decrease in coxal inclination in both the coronal and horizontal planes. The third principal component was related to the sacral inclination in the sagittal plane. The sixth principal component was associated with narrowing of the superior part of the pelvis., Conclusion: The most important factor in the difference between normal and DDH pelvises was the change in the coxal angle in both the coronal and horizontal planes. That is, in the anterior and superior views, the normal pelvis is a triangle, whereas in DDH, it was more like a quadrilateral., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Sasaki et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Developmental dysplasia of the hip (DDH) and femoroacetabular impingement (FAI) are common hip pathologies and important risk factors for osteoarthritis, yet the disease mechanisms differ. DDH involves deficient femoral head coverage and a shortened abductor moment arm, so this study hypothesized that the cross-sectional area (CSA) of the gluteus medius/minimus muscle complex and the stabilizing iliocapsularis muscle would be larger in DDH versus FAI, without increased fatty infiltration. A longitudinal cohort identified prearthritic patients with DDH or FAI who underwent imaging before surgery. Patients with DDH and FAI (Cam, Pincer, or Mixed) were 1:1 matched based on age, sex, and body mass index. Magnetic resonance imaging was used to measure the gluteus medius/minimus complex and iliocapsularis in two transverse planes. Amira software was used to quantify muscle and noncontractile tissue. Paired samples t-tests were performed to compare muscle size and composition (p < 0.05). There were no differences in the iliocapsularis muscle. Patients with DDH had significantly larger CSA of the gluteus medius/minimus complex at both transverse planes, and the noncontractile tissue proportion did not differ. The mean difference in overall muscle CSA at the anterior inferior iliac spine was 4.07 ± 7.4 cm 2 (p = 0.005), with an average difference of 12.1%, and at the femoral head this was 2.40 ± 4.37 cm 2 (p = 0.004), with an average difference of 20.2%. This study reports a larger CSA of the gluteus medius/minimus muscle complex in DDH compared to FAI, without a difference in noncontractile tissue, indicating increased healthy muscle in DDH., (© 2022 Orthopaedic Research Society. Published by Wiley Periodicals LLC.)

Developmental dysplasia of the hip (DDH) is a common condition involving instability of the hip with multifactorial etiology. Early diagnosis and treatment are critical as undetected DDH is an important cause of long-term hip complications. Better diagnostics may be achieved through genetic methods, especially for patients with positive family history. Several candidate genes have been reported but the exact molecular etiology of the disease is yet unknown. In the present study, we performed whole exome sequencing of DDH patients from 28 families with at least two affected first-degree relatives. Four genes previously not associated with DDH (METTL21B, DIS3L2, PPP6R2, and TM4SF19) were identified with the same variants shared among affected family members, in more than two families. Among known association genes, we found damaging variants in DACH1, MYH10, NOTCH2, TBX4, EVC2, OTOG, and SHC3. Mutational burden analysis across the families identified 322 candidate genes, and enriched pathways include the extracellular matrix, cytoskeleton, ion-binding, and detection of mechanical stimulus. Taken altogether, our data suggest a polygenic mode of inheritance for DDH, and we propose that an impaired transduction of the mechanical stimulus is involved in the etiopathological mechanism. Our findings refine our current understanding of candidate causal genes in DDH, and provide a foundation for downstream functional studies., (© 2022. The Author(s).)

Developmental dysplasia of the hip (DDH) is a common anomaly leading to adult osteoarthritis. Environmental and genetic factors contribute to DDH, but its exact genetic mechanism is unclear. In this study, we used whole exome sequencing to identify the causative gene of a DDH pedigree. A rare missense variant in KANSL1 (c.C767T; p.S256F) was identified as the pathogenic cause of DDH. Subsequent mutation screening showed another missense variant in 1 of 200 sporadic patients. Kansl1-mutated mice showed reduced chondrocytes in the acetabulum and a decrease in the cartilage matrix, which may be DDH phenotype-related abnormalities. Furthermore, functional studies showed that cell proliferation was delayed and Mmp13 expression was abnormally upregulated in chondrocytes differentiated from Kansl1 mutant mouse embryonic stem cells. In conclusion, our findings suggest that KANSL1 is a novel pathogenic gene for DDH. The identification of KANSL1 variants has great diagnostic value for identifying individuals with DDH. KEY MESSAGES: Developmental dysplasia of the hip (DDH) is a common anomaly causing adult osteoarthritis. Environmental and genetic factors contribute to DDH, but its exact genetic mechanism is unclear. Using high-throughput whole exome sequencing, we found a novel variant in KANSL1 that was co-inherited by all severely affected individuals diagnosed with DDH from a three-generation family. Further analysis revealed that a Kansl1 variant in mice reduced the number of chondrocytes and decreased cartilage matrix, and mouse embryonic stem differentiation assay showed cartilage defects. These findings indicate a direct association between KANSL1 and hip development, expanding the pathogenic gene spectrum in DDH and providing insight into potential new targets for diagnosing and treating hip dysplasia., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Objective - to justify the use of hip endoprosthesis techniques in dysplastic coxarthrosis depending on the type of dysplasia according to Crowe JF. The study is based on the analysis of hip replacement in 390 patients with dysplastic coxarthrosis, who underwent 436 endoprosthetics. There were 192 patients with type 1 dysplasia according to Crowe, type II - 142, type III - 38 and type IV - 18 patients. The age of patients ranged from 15 to 61 years and averaged 43 years. Pathology was prevalent in women, which accounted for 90 %. Preference was given to prostheses with a cementless type of fixation, which accounted for 89 %. An important task of the surgeon during hip replacement in patients with dysplastic coxarthrosis is to install the acetabulum component of the prosthesis in an anatomical position in compliance with the recommendations of spatial location, especially in types III and IV of dysplasia. Endoprosthetics in types 1 and II of hip dysplasia did not present any difficulties. The amount of bone tissue of the acetabulum of the pelvis is sufficient for the use of cups with primary press-fit fixation. Usually, acetabular components of small size were used. In type III dysplasia, there was a significant deficit of bone tissue of the anterior, posterior columns and acetabular roof. In such cases, bone grafting is used. Shortening of the limb in type III dysplasia, as a rule, does not exceed 4 cm, so the surgery may be performed in one stage and without a shortening osteotomy. In type IV dysplasia with shortening of the lower limb to 4 cm, a single stage endoprosthetics is performed it is possible to perform a shortening osteotomy of the proximal femur. Іn patients with a unilateral process and shortening of the limb more than 4 centimeters, we used the two-stage surgery method. At the first stage, we applied a rod device for external fixation with the introduction of rods into the pelvis and hip, then gradually performed hip traction in order to lower the femoral head to the level of the acetabulum, after which the device was dismantled and at the second stage hip replacement was performed. The acetabular component in hip replacement in Crowe type III or IV dysplasia should be placed in the anatomical position of the acetabulum. If the cranial displacement of the femoral head is less than 4 cm, hip replacement should be performed in one stage. In a unilateral cranial displacement of the femoral head of more than 4 cm, in order to avoid neurovascular bundle traction damage and facilitate the reduction of the prosthesis, preparation should be performed with the reduction of the femoral head to the level of the anatomical acetabulum using an external fixation rod device. It is possible to use a shortening osteotomy of the proximal femur, but then the length of the limb is not restored.

Background: Hip dysplasia, FAI and femoral malrotation often occur together, resulting in mixed symptoms and severe biomechanical limitations of the hip., Objectives: To report on the current recommendations for the best possible diagnosis and treatment strategies of combination pathologies in hip-preserving surgery., Methods: Review and discussion of the relevant literature with consideration of own experience in the treatment of complex combined pathomorphologies of the hip., Results: Patient history and a thorough clinical examination are key for determining the predominant pathomorphologies causing the symptoms. Standardized conventional ap pelvic and axial images of the hip are the basis for the radiological assessment of the hip, supplemented with MRI, CT and animations of the hip, depending on the case. As the pathologies influence each other functionally, a stepwise approach to treatment is recommended. The functionally most relevant pathology is treated first, followed by further corrections as needed. The primary goal is to achieve a stable hip with normal acetabular coverage, followed by an impingement-free range of motion and normalized musculoskeletal function. Care must be taken in the choice of surgical method to ensure that all pathologies can be adequately treated., Conclusion: Complex, combined pathologies of the hip can be treated sufficiently with hip-preserving surgery. A thorough diagnosis is important in order to recognize the functional interaction of the different pathologies. The goal of the surgical therapy is a correctly covered, stable hip with a normal range of motion., (© 2022. The Author(s).)

Acetabular dysplasia results in abnormal forces across the hip joint and can result in both labral tears and cartilage degeneration. A continuum exists from classic dysplasia to normal acetabular morphology. Diagnosis is aided by several radiographic measurements and parameters including a lateral center edge angle of less than 20°, an anterior center edge angle of less than 20°, a Sharp's angle of greater than 42°, and a Tonnis angle of greater than 10°, or version abnormalities. When patients with acetabular dysplasia present with intra-articular hip pain, skeletal maturity, and preserved radiographic joint space, a periacetabular osteotomy (PAO) is considered as a surgical treatment option when conservative measures have failed. The Bernese PAO was developed in 1984 as a way for reorienting the acetabulum to restore more normal femoral head coverage and orientation. The long-term results of this procedure have been promising with 10-year and 20-year survivorships of approximately 85% and 60%, respectively. When dysplasia is coupled with a labral tear or other intra-articular pathology including focal chondral damage, ligamentum teres tears, or capsular defects, hip arthroscopy and PAO are performed. Although there is a paucity in the literature of the long-term evidence for the combined procedure, early results indicate improved patient reported outcome measures. Appropriate treatment of borderline hip dysplasia remains controversial., (Copyright © 2022 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Background: Following open or closed reduction for children with developmental dysplasia of the hip, there remains a significant risk of residual acetabular dysplasia which can compromise the long-term health of the hip joint. The purpose of this study was to use postoperative in-spica magnetic resonance imaging (MRI) data to determine factors predictive of residual acetabular dysplasia at short-term follow-up., Methods: We retrospectively reviewed 63 hips in 48 patients which underwent closed or open reduction and spica casting for developmental dysplasia of the hip. MRI performed in-spica at ∼3-week follow-up were used to assess 11 validated metrics and 2 subjective factors. Acetabular index (AI) was measured on anteroposterior pelvic radiographs at 2-year postoperative follow-up. Binary logistic regression was then used to identify variables predictive of residual dysplasia, defined as an AI greater than the 90th percentile for age based on historic normative data., Results: Average age at surgical reduction was 9.3±3.2 months. 58.7% (37/63) of reductions were open. A total of 43 (68.3%) hips demonstrated residual acetabular dysplasia at 2 years postoperatively based on normative values. In those with persistent dysplasia, patients were on average older at the time of reduction (10.0 mo±3.2 vs. 8.0 mo±2.8, P=0.010) and more likely female (88.4% vs. 60.0%, P=0.010). Patients with residual dysplasia were more likely to have mild subluxation on postoperative MRI (40.0% vs. 10.5%, P=0.022). Hips with a cartilaginous acetabular index (CAI) of >23 degrees were 7.6 times more likely to develop residual dysplasia. Type of reduction (ie, closed vs. open) did not appear to influence the rate of residual dysplasia (P=0.682)., Conclusion: In this series, the rate of residual dysplasia after surgical reduction was higher than most previous reports, with no appreciable difference between closed and open reductions. Older age, female sex, and a higher CAI were associated with a greater risk of persistent radiographic dysplasia. In particular, hips with a CAI >23 degrees were 7.6 times more likely to be dysplastic at 2-year follow-up., Level of Evidence: Level III., Competing Interests: The authors declare no conflicts of interest., (Copyright © 2022 Wolters Kluwer Health, Inc. All rights reserved.)

Residual hip dysplasia may exist despite appropriate treatment of congenital hip dysplasia (CHD). The abnormalities chiefly affect the acetabulum and can lead to premature osteoarthritis. Although the main cause is delayed treatment of CHD, primary lesions are also possible and may be worsened by the initial treatment itself. Residual hip dysplasia must be detected during the follow-up of patients with CHD. The antero-posterior radiograph of the pelvis is the main diagnostic tool. However, the importance of non-ossified anatomical structures requires additional investigations such as arthrography and magnetic resonance imaging. The risk of premature osteoarthritis is difficult to predict based only on the imaging-study findings. Hip dysplasia is best treated before 5 years of age. The work-up at this age should allow determination of the best treatment. Surgery is required but should not be performed unnecessarily. The decision rests on the absence of improvement in the radiographic criteria and on the findings from additional imaging studies. The usual treatment is Salter's osteotomy, during which excessive anterior displacement should be avoided. At adolescence, the information provided by radiography in the coronal plane should be completed by a three-dimensional evaluation of the acetabulum and an assessment of the quality of the labrum. The shelf procedure has been proven to relieve pain and to significantly postpone the need for hip arthroplasty, when performed early, before the development of visible osteoarthritis, and on a congruent hip. Chiari's osteotomy has a role to play in complex dysplasia affecting both the acetabulum and the femur. Periacetabular osteotomy is getting more used thanks to cooperation between paediatric and adult orthopaedic surgeons. This osteotomy provides optimal correction in all three dimensions., (Copyright © 2021 Elsevier Masson SAS. All rights reserved.)

Using an animal model, we aimed to investigate the effects of an inverted limbus on acetabular development following closed reduction of developmental dysplasia of the hip (DDH). We interpositioned the menisci of 5-week-old rabbits (n = 40) into the hip joints to simulate limbus inversion following closed reduction for DDH. The acetabular index (AI) on anteroposterior pelvic radiographs and magnetic resonance imaging were used to evaluate acetabular development. Animals were euthanized at 4 and 8 weeks after surgery. Histological sections of the acetabular cartilage were stained and scored in accordance with the modified Mankin system. Scanning electron microscopy and transmission electron microscopy were used to examine the ultrastructure of the acetabular cartilage. Terminal deoxynucleotidyl transferase dUTP nick end-labeling staining was used to evaluate chondrocyte apoptosis. Immunohistochemistry and Western blot analyses were used to examine the expression of type X collagen (Col-X) and matrix metalloproteinase 13 (MMP-13) in the acetabular cartilage. AI values increased over a period and were higher in the experimental group than in the sham group. In the experimental group, the acetabular surface had become rough and had split in some cases. Chondrocytes within the acetabular cartilage had become hypertrophic, gradually forming clusters, and taking on an apoptotic appearance. Col-X and MMP-13 expression also increased with time. Our findings suggest that residual limbus inversion following closed reduction for DDH can cause progressive dysplasia of the acetabulum, apoptosis of acetabular chondrocytes, accelerated cartilage degeneration, and even early-stage osteoarthritis., (© 2021 Orthopaedic Research Society. Published by Wiley Periodicals LLC.)

The high hip center technique (HHC) is considered to be feasible for acetabular reconstruction in patients with DDH, but there is little in-depth study of its specific impact on Crowe type II and III DDH. The purpose of this study was to simultaneously analyze the effect of HHC on bone coverage of the cup (CC) in the acetabular reconstruction of type II and III DDH patients and to propose a map of acetabular bone defects from the perspective of the cup. Forty-nine hip CT data of 39 patients with DDH (Crowe type II and III) were collected to simulate acetabular reconstruction by cup models of different sizes (diameter 38mm-50 mm, 2 mm increment) with the HHC technique. The frequency distribution was plotted by overlapping the portions of the 44 mm cups that were not covered by the host bone. The mean CC of cups with sizes of 38 mm, 40 mm, 42 mm, 44 mm, 46 mm, 48 mm, and 50 mm at the true acetabula were 77.85%, 76.71%, 75.73%, 74.56%, 73.68%, 72.51%, and 71.75%, respectively, and the maximum CC increments were 21.24%, 21.58%, 20.86%, 20.04%, 18.62%, 17.18%, and 15.42% (P < 0.001), respectively, after the cups were elevated from the true acetabula. The bone defect map shows that 95% of type II and III DDH acetabula had posterosuperior bone defects, and approximately 60% were located outside the force line of the hip joint. Acetabular cups can meet a CC of more than 70% at the true acetabulum, and approximately 60% of Crowe type II and III DDH patients can obtain satisfactory CC at the true acetabulum by using a 44-mm cup without additional operations., (© 2021. The Author(s).)

Congenital diaphragmatic hernia (CDH) is a severe congenital anomaly that is often accompanied by other anomalies. Although the role of genetics in the pathogenesis of CDH has been established, only a small number of disease-associated genes have been identified. To further investigate the genetics of CDH, we analyzed de novo coding variants in 827 proband-parent trios and confirmed an overall significant enrichment of damaging de novo variants, especially in constrained genes. We identified LONP1 (lon peptidase 1, mitochondrial) and ALYREF (Aly/REF export factor) as candidate CDH-associated genes on the basis of de novo variants at a false discovery rate below 0.05. We also performed ultra-rare variant association analyses in 748 affected individuals and 11,220 ancestry-matched population control individuals and identified LONP1 as a risk gene contributing to CDH through both de novo and ultra-rare inherited largely heterozygous variants clustered in the core of the domains and segregating with CDH in affected familial individuals. Approximately 3% of our CDH cohort who are heterozygous with ultra-rare predicted damaging variants in LONP1 have a range of clinical phenotypes, including other anomalies in some individuals and higher mortality and requirement for extracorporeal membrane oxygenation. Mice with lung epithelium-specific deletion of Lonp1 die immediately after birth, most likely because of the observed severe reduction of lung growth, a known contributor to the high mortality in humans. Our findings of both de novo and inherited rare variants in the same gene may have implications in the design and analysis for other genetic studies of congenital anomalies., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2021 American Society of Human Genetics. Published by Elsevier Inc. All rights reserved.)

Rationale: Exact restoration of the rotation center in total hip arthroplasty (THA) is technically challenging in patients with end-stage osteoarthritis due to developmental dysplasia of the hip (DDH), especially in the Crowe type II and III procedures. The technical difficulty is attributable to the complex acetabular changes. In this study, a novel 3-dimensional (3D) printed integral customized acetabular prosthesis for anatomical rotation restoration in THA for DDH Crowe type III was developed using patient-specific Computer-aided design and additive manufacturing (AM) methods., Patient Concerns: A 69-year-old female patient had developed left hip joint pain and restricted movement for 40 years; the symptoms had increased in the past 5 months. Pain, limited motion of the left hip joint, and lower limb length discrepancy were noted during physical examination., Diagnosis: The patient was diagnosed with left hip end-stage osteoarthritis secondary to DDH (Crowe type III)., Intervention: A 3D printed acetabulum model was manufactured and a simulated operation was performed to improve the accuracy of reconstruction of the rotation center and bone defect. A 3D printed titanium alloy integral customized acetabular prosthesis was designed according to the result of simulated operation. The integral customized prothesis was implanted subsequently via the posterolateral approach. Radiography of the pelvis and Harris score assessment were performed during the perioperative period as well as at the 6- and 12-month follow-up., Outcomes: The 3D printed integral customized acetabular prosthesis matched precisely with the reamed acetabulum. The rotation center was restored and the bone defect was exactly reconstructed. There were no signs of prosthetic loosening at the 12-month follow-up. The Harris score gradually improved during the follow-up period., Lessons: Satisfactory results of hip rotation restoration and bone defect reconstruction could be achieved by using 3D printed integral customized acetabular prosthesis, which provides a promising way to reconstruct the acetabulum in patients with DDH anatomically and rapidly for THA.

Purpose: To evaluate the association of labral length with acetabular morphology and clinical symptoms., Methods: Patients treated at our hip joint clinic between January 2015 and December 2018 were retrospectively enrolled in the study. Our sample included patients who received a diagnosis of one or more of the following: hip labral tear, femoroacetabular impingement (FAI), and developmental dysplasia of the hip. Patients with osteoarthritis and/or osteonecrosis were excluded. Bilateral labral length was measured as the distance from the acetabular rim to the edge of the labrum at the level of the central coronal T1-weighted magnetic resonance imaging scan cross-referenced to the axial plane (3- to 9-o'clock position). The lateral center-edge angle (LCEA) and acetabular roof obliquity (ARO) were evaluated with plain radiographs. An LCEA of 25° or less was defined as developmental dysplasia of the hip, whereas a positive crossover sign in the presence of an LCEA of 30° or greater, an LCEA greater than 40°, or acetabular inclination lower 0° was defined as pincer FAI. An alpha angle greater than 50° or head-neck offset lower 8 mm was considered cam FAI. The severity of hip symptoms was evaluated bilaterally using the Japanese Orthopaedic Association pain scale, on which hips scoring full points (i.e., a perfect score) were defined as asymptomatic whereas hips with all other scores were considered symptomatic. We used simple linear regression to examine the correlations of labral length with the LCEA and ARO. Labral length was also compared according to patient hip symptom status using the Mann-Whitney U test., Results: The study included 102 patients (14 with bilateral symptoms and 88 with unilateral symptoms). Labral length was strongly correlated with the LCEA (r = -0.612, P < .001) and ARO (r = 0.635, P < .001). Additionally, patients with symptomatic hips had significantly larger labra (9.5 ± 3.0 mm) than those with asymptomatic hips (7.9 ± 2.1 mm, P = .004)., Conclusions: Acetabular labral length is significantly greater in dysplastic, irregularly congruent, symptomatic hips., Level of Evidence: Level Ⅳ, retrospective cross-sectional study., (Copyright © 2020 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Developmental dysplasia of the hip encompasses a range of hip abnormalities in which the femoral head and acetabulum fail to develop and articulate anatomically. Developmental dysplasia of the hip is a clinically important condition, with a prevalence of 1-2/1000 in unscreened populations and 5-30/1000 in clinically screened populations. The pathology is incongruence between the femoral head and the acetabulum, which can be caused by an abnormally shaped femoral head, acetabulum, or both. This results in a spectrum of different hip abnormalities. The precise aetiology behind developmental dysplasia of the hip is unclear, but there are a number of established risk factors. In the UK, universal clinical examination of newborns and 6-8-week-old babies is performed under the national UK newborn screening programme for developmental dysplasia of the hip (part of the Newborn and Infant Physical Examination). The physical examination of the newborn hip involves initial inspection of the infant for any of the clinical features of developmental dysplasia of the hip, followed by hip stability tests (Barlow's and Ortolani's tests). Hip ultrasound is the gold standard diagnostic and monitoring tool for developmental dysplasia of the hip in newborns and infants under 6 months of age, or until ossification of the femoral head. Some mild cases of developmental dysplasia of the hip (and the immature hip) resolve without requiring intervention; however, there are a number of treatments, both non-operative and operative, that may be used at various stages of this condition.

Aim: To investigate the three-dimensional anatomy and shape of the proximal femur, comparing patients with secondary osteoarthritis (OA) due to mild developmental dysplasia of the hip (DDH) and primary hip OA., Materials and Methods: This retrospective radiographic computed tomography (CT)-based study investigated proximal femoral anatomy in a consecutive series of 84 patients with secondary hip OA due to mild DDH (Crowe type I&II/Hartofilakidis A) compared to 84 patients with primary hip OA, matched for gender, age at surgery, and body mass index., Results: Men with DDH showed higher neck shaft angles (127±5° vs. 123±4°; p<0.001), whereas women with DDH had a larger femoral head diameter (46±4 vs. 44±3 mm; p=0.002), smaller femoral offset (36±5 vs. 40±4 mm; p<0.001), decreased leg torsion (25±13° vs. 31±16°; p=0.037), and a higher neck shaft angle (128±7° vs. 123±4°; p<0.001) compared to primary OA patients. Similar patterns of the three-dimensional endosteal canal shape of the proximal femur, but a high inter-individual variability for femoral canal torsion at the meta-diaphyseal level were found for DDH and primary OA patients., Conclusion: Standard cementless stem designs are suitable to treat patients with secondary hip OA due to mild DDH; however, high patient variability and subtle anatomical differences in the proximal femur should be respected., (Copyright © 2019 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.)

Background: It was previously reported that pelvises with developmental dysplasia of the hip are tilted anteriorly, which increases bony coverage of the femoral head. This study aimed to investigate the correlation between anatomical parameters of the pelvis such as pelvic incidence and anatomical pelvic tilt and functional parameters of the spine and pelvis such as tilt of the anterior pelvic plane., Methods: We examined 84 female patients with bilateral developmental dysplasia of the hip who had undergone curved periacetabular osteotomy at author's institution. Radiographs of the thoracic to lumbar spines and the pelvis were obtained in the standing position to measure spino-pelvic parameters before surgery. Morphological parameters of the acetabulum such as the anterior center-edge (CE) angle, posterior CE angle, lateral CE angle, and acetabular anteversion were measured using a preoperative three-dimensional pelvic model reconstructed from computed tomography images. Pearson's correlation analysis was conducted to evaluate the relationship of these parameters., Results: With regard to correlations between pelvic incidence (PI) and other parameters, the sacral slope (SS) value (r = 0.666) was the highest among functional parameters and the anatomical-SS value (r = 0.789) was the highest among morphological parameters. There were moderate correlations of the anterior pelvic plane angle (APPA) with pelvic tilt (PT) (r = - 0.594) and anatomical-PT (r = 0.646). With regard to correlations between spino-pelvic parameters and bony morphological parameters of the acetabulum, there was a moderate correlation between anatomical-PT and acetabular anteversion (AA) (r = 0.424). There were moderate correlations of APPA with the anterior CE angle (r = - 0.478), posterior CE angle (r = 0.432), and AA (r = 0.565). APPA had a stronger correlation with anatomical-PT (r = 0.646) than with AA., Conclusions: The tilt of the pelvis may be more dependent on anatomical-PT, a morphological parameter of the pelvis, than the lateral CE angle, anterior CE angle, posterior CE angle, and acetabular anteversion on bony coverage of the acetabulum. This study is the first to investigate the correlation between functional parameters of the pelvis and spine and morphological parameters of the pelvis and acetabulum besides PI.

Rationale: Cerebral, ocular, dental, auricular, skeletal anomalies (CODAS) syndrome is a very rare multisystem disorder, which shows malformations of the central nervous system, ears, eyes, teeth, and skeleton that was first reported in 1991. Only a few cases that sporadically occurred have been reported worldwide. The research investigating the pathogenesis and patterns of CODAS inheritance is still ongoing. There is no satisfactory treatment for this rare genetic disease yet. Due to the lack of curative medical treatment, rehabilitation could play a major role in treatment for genetic disease., Patient Concerns: To our best knowledge, the 2 children described in this study are the only CODAS syndromes siblings reported in the world so far. These Korean siblings show highly distinctive features consisting of developmental delay, cataracts, vulnerability to tooth decay, epiphyseal dysplasia, and anomalous ears., Diagnoses: CODAS syndrome., Interventions: Comprehensive long-term rehabilitation treatment during 5 years., Outcomes: We report on the progress of the comprehensive long-term rehabilitation treatment at 5-year follow-up. Their fine motor and language skills development improved similarly to that of same-aged children. We observed the positive effect of rehabilitation on the quality of life., Lessons: The therapy of genetic disorders is challenging for pediatric neurologists and pediatric physiatrists. We suggest that rehabilitation is the best treatment currently available for this genetic disease that yields satisfactory therapeutic effect.

In this computed tomography (CT) morphological study we describe the way the proximal femoral morphology differs with worsening degrees of developmental dysplasia of the hip (DDH) and describe gender differences in patients with DDH. Forty-nine male patients with DDH were matched with 49 females with DDH, using age and the Crowe classification of DDH severity. The femoral length, anteversion, neck-shaft angle, offset, neck length, canal-calcar ratio, canal flare index, lateral center-edge angle, alpha angle, pelvic tilt, and pelvic incidence were measured for each patient on their pre-operative CT scans, prior to total hip arthroplasty surgery. Femoral anteversion and neck length were 16° and 47 mm, 25°and 36 mm, 26° and 43 mm, and 44° and 36 mm, for Crowe I and III males and Crowe I and III females, respectively. The mean male anteversion was 22° (±14), compared to 30° (±15.5) in females (p = 0.02, Confidence Interval: 1.6-14.9). Gender differences in femoral length, neck length and offset lost significance when height-normalized and no other significant gender differences were found. In conclusion, femoral neck length reduces with increasing DDH severity, whilst anteversion tends to increase. Male patients with DDH have significantly less femoral anteversion, which has important implications for osteotomy and arthroplasty surgery in DDH. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res., (© 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Developmental dysplasia of the hip (DDH) is a common congenital malformation characterized by mismatch in shape between the femoral head and acetabulum, and leads to hip dysplasia. To date, the pathogenesis of DDH is poorly understood and may involve multiple factors, including genetic predisposition. However, comprehensive genetic analysis has not been applied to investigate a genetic component of DDH. In the present study, 10 pairs of healthy fathers and DDH daughters were enrolled to identify genetic hallmarks of DDH using high throughput whole genome sequencing. The DDH-specific DNA mutations were found in each patient. Overall 1344 genes contained DDH-specific mutations. Functional enrichment analysis showed that these genes played important roles in the cytoskeleton, microtubule cytoskeleton, sarcoplasm and microtubule associated complex. These functions affected osteoblast and osteoclast development. Therefore, we proposed that the DDH-specific mutations might affect bone development, and caused DDH. Our pairwise high throughput sequencing results comprehensively delineated genetic hallmarks of DDH. Further research into the biological impact of these mutations may inform the development of DDH diagnostic tools and allow neonatal gene screening., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Although increasing evidence suggests that abnormal femur geometry in developmental dysplasia of the hip (DDH) may contribute to intra-articular damage and the development of hip osteoarthritis, a comprehensive 3D description of femoral abnormalities in DDH remains incomplete. Statistical shape modeling (SSM) was used to quantify three-dimensional (3D) geometric variation among femurs in female patients with DDH and control subjects. SSM correspondence points (n = 8,192) were placed on each femur using a gradient descent energy function to derive mean DDH and control femoral shapes and principal component analysis (PCA) was then used to describe shape variation. PCA results were associated with common 2D radiographic measures of femur shape using general linear models. For patients with DDH, the first eight principal components (modes) captured 90.9% of the cumulative variance accounted for (VAF). Notably, mode 2 captured 23.6% VAF and described variation in femoral version, the neck-shaft angle, and femoral neck length, while mode 3 captured 16.4% VAF and described variation in femoral version, femoral head size, and femoral offset. SSM captured complex geometric deformities in DDH, which may not be fully described by 2D measures of the acetabulum and proximal femur alone. By determining the primary shape variations among femurs in cases of DDH, SSM may further understanding of pathologies on the femoral side of dysplastic hips, in context with more commonly recognized acetabular deformities. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res., (© 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Background: Radiographs play a central role in the evaluation of the extent of arthritic change and the quantification of morphological parameters characteristic of femoroacetabular impingement (FAI) and/or dysplasia. Reporting of these parameters is widespread in the literature, occasionally as an instrument for data pooling in collaborative research endeavors. Yet, the metrological properties of commonly used radiographic descriptors of acetabular and femoral architecture relevant to the field of hip preservation have not been reviewed systematically. The purpose of the present review was twofold: (1) to identify the current body of data available on the reliability of commonly used radiographic descriptors of the pre-arthritic hip and (2) to collate best practices and methodological pearls and pitfalls from the existing investigations that have explored the reliability of these radiographic measures., Methods: Article screening methodology involved an extensive search of 2 databases (PubMed Central, Embase). Metrological reliability data and best practices and frequencies with which these practices have been reported in existing investigations were extracted from the methods of the included studies. The radiographic parameters that were chosen as a focus for the present review were based on a discussion among a number of experienced hip-preservation surgeons., Results: Forty-three articles met all inclusion criteria and were included in this review. Eleven recurring components of study design were isolated from the included investigations as being critical for minimizing bias in the assessment of the reliability of these radiographic morphological parameters. Sixteen (37.2%) of the included studies reported the use of at least 1 quality-control measure for ensuring radiographic integrity. The radiographic parameters with the most reliability data included the lateral center-edge angle (22 studies), the Tönnis angle (14 studies), and the alpha angle (18 studies). Categorical markers of acetabular retroversion and the extent of osteoarthritis have been less-frequently studied with respect to their reliability, with the exception of the crossover sign, which was evaluated in 11 of the included studies., Conclusions: The radiographic parameter with the most metrological evidence in support of its reliability was the lateral center-edge angle (with 22 [100%] of 22 studies reporting acceptable reliability), whereas the Tönnis grade of osteoarthritis consistently demonstrated subpar interrater and intrarater reliability. Side-arm investigations for testing reliability may be needed by individual studies to prove the validity of data-pooling practices as collaborative endeavors continue to become more widespread.

Background: Plain radiography is the most often imaging method used for postoperative assessment of inveterate developmental dysplasia of the hip. This technique does not permit to achieve an accurate diagnose of intra-articular changes, specifically articular congruity., Objective: analyze the morphological changes of the acetabular volume by computed tomography, in patients operated by medium adductor myotomy, psoas tenotomy, open hip reduction, diaphysectomy, varus osteotomy and derotating and Dega-type acetabuloplasty., Method: A pilot clinical trial was conducted including six patients with unilateral inveterate dysplasia admitted to the Rehabilitation National Institute. Computed tomography were analyzed using an engineering design software., Results: It was found that in all cases analyzed, operated acetabular volume was greater than the contralateral (8 to 48%), however, no significant difference between the volumes was found (p = 2.46). Significant difference between the volume and the age of patients, in multifactorial ANOVA tests (p = 0.006), Cochran's (p = 0.00019) and Kruskal-Wallis (p = 2.925 × 10 -8 ) was found., Conclusion: It is clear that the proposed measurement technique is able to identify differences between volumes (operated and contralateral). The clinical monitoring of these patients can validate the results obtained by this measurement technique, and it will serve to estimate the effectiveness of the surgical technique applied in patients., (Copyright: © 2019 Permanyer.)

Developmental dysplasia of the hip (DDH) is one of the most common congenital disorders in childhood. Its diverse pathological changes require different treatments and result in different outcomes. Although many studies have been conducted on DDH, some special pathology is still unrecognized. We here presented a rare case of a one-year and eleven-month old girl with DDH; a half-free intra-articular osteocartilaginous tissue was found in her right hip joint. X-ray, computer assisted tomography (CT) and magnetic resonance imaging (MRI) were performed to evaluate the pathological changes. MRI revealed some positive findings. The patient experienced open reduction and histopathological examination of the small tissue. Through gross anatomy it is a half-free intra-articular osteocartilaginous tissue, which can fully match a fossa observed at the femoral head. Histopathological examination found that the tissue was composed of collagenous fiber and cartilage-like tissue. Interestingly, we found the expression of type I collagen according to immunohistochemical analysis, which indicated that the cartilage-like tissue was formed due to laceration of the articular cartilage. This kind of disorder should be included as one of the pathologies of DDH. The most possible origin of this tissue is the femoral head which we speculate may have been fractured before., (Copyright © 2018 Daping Hospital and the Research Institute of Surgery of the Third Military Medical University. Production and hosting by Elsevier B.V. All rights reserved.)

Purpose: The purpose of this study is to clarify morphological changes of acetabular subchondral bone cyst after total hip arthroplasty for osteoarthritis secondary to developmental dysplasia of the hip., Methods: Two hundred and sixty-one primary cementless total hip arthroplasties of 208 patients, 18 males, 190 females, were retrospectively reviewed. Morphological changes of subchondral bone cyst were evaluated by computed tomography (CT). The mean cross-sectional area of the cyst from CT scans at 3 months postoperatively and after 7-10 years (average 8.4 years) were compared., Results: Acetabular subchondral bone cysts were found in 49.0% of all cases in preoperative CT scans. There was no cyst which was newly recognized in CT scan performed after postoperative 7-10 years. All the cross-sectional areas of the cysts evaluated in this study were reduced postoperatively., Conclusions: This study revealed that acetabular subchondral bone cysts do not increase or expand after total hip arthroplasty and indicated that the longitudinal morphological change of acetabular bone cysts in patients of developmental dysplasia of the hip do not influence long-term implant fixation in total hip arthroplasty.

Background: One of the important pathologic changes in developmental dysplasia of the hip (DDH) is increased acetabular version angle (AA). Reasonable correction for excessive AA is an important step in the treatment of DDH, making accurate AA measurement very crucial. However, the results of different AA measurement methods vary. Thus, this study aimed to compare the difference in AA measurements between 2-dimensional computed tomography (2D-CT) and 3-dimensional computed tomography (3D-CT) in children with DDH and to identify the AA degree in children with DDH to guide treatment., Methods: AA was measured by 2D-CT and 3D-CT in 186 children with DDH, and the measurement results were compared with the physical measurement result in the 3D-printed pelvis (3D-PP) model. The 3D-PP was a 1:1 model identical to the human pelvis. All patients were unilaterally affected., Results: The results of AA measurement through 2D-CT, 3D-CT, and 3D-PP of normal hips were 14.0±6.6, 11.9±5.3, and 11.9±3.4 degrees, respectively, whereas those of the dislocated hips were 24.9±8.9, 19.8±5.2, and 19.5±4.3 degrees, respectively. In both the normal and dislocated hip groups, the results between 2D-CT and 3D-CT was significantly different (P<0.05), but there was no difference between the results of 3D-CT and 3D-PP (P>0.05). The AA of the normal and dislocated hips as measured by 3D-PP was 11.9±3.6 and 19.6±4.3 degrees, respectively, with statistically significant difference (P<0.05). In the dislocated hips, a significant positive correlation was found between age and AA (r=0.756, P<0.05) and between AA and degree of dislocation (r=0.837, P<0.05)., Conclusions: 3D-CT is more accurate than 2D-CT for AA measurement, and compared with normal hips, AA in dislocated hips increased by ∼7.7 degrees on average. AA increases as age and degree of dislocation increase., Level of Evidence: Level II.

Developmental dysplasia of the hip (DDH) is a developmental defect that prevents normal articulation between the acetabulum and the femoral head. This is an unusual condition, with a prevalence of 1-2 per thousand, and with only two poorly described skeletons documented in South American paleopathological literature. In this work we report an individual with such a condition, from the archeological site Tres Cruces I (Quebrada del Toro, Salta, Argentina). Several radiocarbon dates and associated materials date it to the Superior Formative (400-1000 AD). The remains are of an adult female, who also has tabular oblique cranial modification. Through detection of abnormalities in the morphology of the femora and ossa coxae, a differential diagnosis was carried out. On the left hip joint the formation of a well-defined false acetabulum, without connection with the true one, was observed. The latter was shallow, triangular, with an irregular base. The left os coxae showed a wider greater sciatic notch angle. The right os coxae exhibited a false acetabulum connected with the true one. Both femora presented a small femoral head, flat and mushroom-shaped, with shortening of the neck. These features were more pronounced on the right-side elements. On the basis of the aforementioned, a presumptive diagnosis of bilateral developmental dysplasia of the hip with complete dislocation on both sides was established., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Objective: Alterations in the connective tissue of the hip joint capsule and ligaments might account for the increased laxity seen in patients with developmental dysplasia of the hip. The tensile features of the connective tissue depend on collagen. A number of prior studies have noted the association between the trace elements and collagen biosynthesis. The aim of this research is to determine whether there exists an association between the trace elements and developmental dysplasia of the hip., Patients and Methods: This investigation included 27 patients with developmental dysplasia of the hip (18 females and nine males; mean age 24.3 ± 6.3 months, range 18–36 months) and 26 healthy controls (15 females and 11 males; mean age 23.8 ± 5.4 months, range 18-36 months). The levels of the serum trace elements in the groups were statistically compared., Results: The Cu levels of the patients with developmental dysplasia of hip were statistically higher than those of the control group (p<0.05). The Zn, Fe, Mg, and Mn levels of the patients with developmental dysplasia of hip were statistically lower than those of the control group (p<0.05)., Conclusions: We found an association between developmental dysplasia of the hip and the serum trace element levels. We, therefore, believe that the trace element levels may shed light on the etiopathogenesis of developmental dysplasia of the hip. This work should be supported by future studies concerning the causes of the alterations in the serum trace element levels seen in patients with developmental dysplasia of the hip.

Objective Closed reduction (CR) is a noninvasive treatment for developmental dysplasia of the hip (DDH), and this treatment is confirmed intraoperatively. This study aimed to develop a preoperative estimation model of the probability of requiring open reduction (OR) for DDH. Methods The study design was cross-sectional by screening all patients younger than 2 years who had attempted CR between October 2012 and July 2016 by a single surgeon. Potential diagnostic determinants were sex, age, side, bilaterality, International Hip Dysplasia Institute (IHDI) grade, and acetabular index (AI). An intraoperative arthrogram was the reference standard. A logistic regression equation was built from a reduced model. Bootstrapping was performed for internal validity. Results A total of 164 hips in 104 patients who met the inclusion criteria were analysed. The prevalence of CR was 72.2%. Independent factors for OR were older age, higher IHDI grade, and lower AI. The probability of OR = 1/[1 + exp - (-2.753 + 0.112 × age (months) + 1.965 × IHDI grade III (0 or 1) + 3.515 × IHDI grade IV (0 or 1) - 0.058 × AI (degrees)]. The area under the curve was 0.79. Conclusion This equation is an objective tool that can be used to estimate the requirement for OR.

Background: Developmental dysplasia of the hip (DDH) is a debilitating condition whose distinguishing signs include incomplete formation of the acetabulum leading to dislocation of the femur, accelerated wear of the articular cartilage and joint laxity resulting in osteoarthritis. It is a complex disorder having environmental and genetic causes. Existing techniques fail to detect milder forms of DDH in newborns leading to hip osteoarthritis in young adults. A sensitive, specific and cost effective test would allow identification of newborns that could be non-invasively corrected by the use of a Pavlik harness. Previously, we identified a 2.5 MB candidate region on human chromosome 3 by using linkage analysis of a 4 generation, 72 member family. Whole exome sequencing of the DNA of 4 severely affected members revealed a single nucleotide polymorphism variant, rs3732378 co-inherited by all 11 affected family members. This variant causes a threonine to methionine amino acid change in the coding sequence of the CX3CR1 chemokine receptor and is predicted to be harmful to the function of the protein To gain further insight into the function of this mutation we examined the effect of CX3CR1 ablation on the architecture of the mouse acetabulum and on the murine gait., Methods: The hips of 5 and 8 weeks old wild type and CX3CR1 KO mice were analyzed using micro-CT to measure acetabular diameter and ten additional dimensional parameters. Eight week old mice were gait tested using an inclined treadmill with and without load and then underwent micro-CT analysis., Results: (1) KO mice showed larger a 5-17% larger diameter left acetabula than WT mice at both ages. (2) At 8 weeks the normalized area of space (i.e. size discrepancy) between the femur head and acetabulum is significantly larger [38% (p = 0.001)-21% (p = 0.037)] in the KO mice. (3) At 8 weeks gait analysis of these same mice shows several metrics that are consistent with impairment in the KO but not the WT mice. These deficits are often seen in mice and humans who develop hip OA., Conclusion: The effect of CX3CR1 deletion on murine acetabular development provides suggestive evidence of a susceptibility inducing role of the CX3CR1 gene on DDH.

Background: The results of cementless stems in total hip arthroplasty (THA) done because of congenital dislocation with step-cut osteotomy is not well known, particularly the influence of the design and the role of extent of porous coating. Therefore we performed a retrospective study to evaluate the mid to long-term results THA performed with a single type acetabular component and different geometry and fixation type stems with ceramic bearings in the setting of step-cut subtrochanteric osteotomy in high hip dislocated (HHD) patients. We asked if the stem type affect the outcomes in terms of (1) intra and postoperative complication rates (2) radiographic outcomes (3) prosthesis survival in step-cut subtrochanteric shortening osteotomy., Hypothesis: The type of the stem, whether cylindrical or tapered does not affect the outcome if the femoral canal fit and fill is obtained and the step-cut femoral shortening osteotomy is primarily fixed., Materials and Methods: Forty-five hips in 35 patients with a mean follow up of 10 years (range, 7-14 years) were evaluated. The single type cementless cup was placed at the level of the true acetabulum, a step-cut shortening femoral osteotomy was performed and reconstruction was performed with two different types of tapered stem in twenty-two hips (Synergy™ and Image™ proximally coated, Smith and Nephew, Menphis, TN, USA) and one type of cylindrical stem (Echelon™ with 2/3 coated, Smith and Nephew, Menphis, TN, USA) in twenty-three hips. Harris hip scores (HHS) and a University of California Los Angeles (UCLA) activity scores were calculated for all patients and successive X-rays were evaluated regarding component loosening and osteolysis, along with complications related to bearing, step-cut osteotomy and stem types., Results: Forty-one hips (91%) had good and excellent clinical outcome according to HHS. The mean UCLA activity scores improved from 3.2±0.6 points (range, 2-4) preoperatively to 6.3 points±0.5 (range, 5-7) at the latest follow-up. The mean femoral shortening was 36±10mm (range, 20-65mm). Four (9%) dislocations were observed. There were five (11%) intra-operative femoral fractures and three (7%) cases of non-union, which were observed in tapered stems. Cylindrical stems had superior neutral alignment primarily. With any stem revision as the end point, cylindrical stems had a higher survival rate (100%) than all tapered stems (82%; 95% confident interval [CI] 77-97%) at ten years. With any revision as the end point, the 10-year survival rate for acetabular component (Reflection-Ceramic Interfit) and for femoral components were 98% (95% CI, 85-99%) and 91% (95% CI, 78-97%), respectively., Conclusions: There were more implant related complications in HHD patients undergoing THA when tapered stems with 1/3 proximal coating were used to reconstruct a step cut osteotomized femur, compared to cylindrical stems 2/3 coated., Level of Evidence: IV, retrospective study., (Copyright © 2017 Elsevier Masson SAS. All rights reserved.)

Background: Implantation of the acetabular cup insert in the "true" location of the acetabulum is a fundamental principle of total hip arthroplasty for the treatment of secondary osteoarthritis due to developmental dysplasia of the hip (DDH). As knowledge of the morphology of the acetabulum is required for accurate placement, we investigated the relationship between acetabular width and the Crowe classification of subluxation percentage of the hip. We also analyzed factors associated with the acetabular width ratio (AWR), defined as the acetabular width of the dysplastic hip divided by that of the unaffected, contralateral hip., Methods: We completed a retrospective review of the preoperative standard anteroposterior radiographs and computed tomography (CT) scans of 207 female patients who underwent primary total hip arthroplasty for unilateral DDH. The "true" acetabular plane was defined on each CT reconstruction as a plane perpendicular to the anterior pelvic plane, parallel to the teardrop line, and passing through the center of the femoral head on the unaffected, contralateral side. The acetabular width was measured for both the affected hip and the contralateral, reference hip on the true acetabular plane, with the acetabular width defined as the distance between the edges of the anterior and posterior walls of the acetabulum. All hips were classified according to the Crowe groupings on the basis of the subluxation percentage of the dysplastic hip; the subluxation percentage increased from groups I to IV, with group IVb showing joint dislocation., Results: The acetabular width decreased from Crowe groups I to IVb, with a negative correlation found between the AWR and the subluxation percentage (Spearman correlation coefficient, ρ = -0.404; p < 0.001). Multivariate regression analysis identified subluxation percentage and femoral neck-shaft angle as independent factors associated with the AWR., Conclusions: Characterization of factors associated with the AWR, namely subluxation percentage and femoral neck-shaft angle, will guide surgeons in correctly implanting the acetabular cup insert during total hip arthroplasty in patients with DDH.

Developmental dysplasia of the hip (DDH) is a common musculoskeletal disorder characterized by a mismatch between acetabulum and femoral head. Mechanical force plays an important role during the occurrence and development of abnormities in acetabulum and femoral head. In this study, we established a mechanical force model named cyclic compressive stress (Ccs). To analyze the effect of Ccs on DDH, we detected special genes in chondrocytes and osteoblasts. Results showed that Ccs downregulated chondrogenesis of ADTC5 in a concentration-dependent manner. Moreover, the mRNA level of Scinderin (Scin) considerably increased. We established lentivirus-SCIN(GV144-SCIN) to transfect hBMSCs, which were treated with different Ccs levels (0.25 Hz*5 cm, 0.5 Hz*5 cm, and 1 Hz*10 cm); the result showed that overexpression of Scin upregulated osteogenesis and osteoclastogenesis. By contrast, expression of chondrocyte-specific genes, including ACAN, COL-2A, and Sox9, decreased. Further molecular investigation demonstrated that Scin promoted osteogenesis and osteoclastogenesis through activation of the p-Smad1/5/8, NF-κB, and MAPK P38 signaling pathways, as well as stimulated the expression of key osteoclast transcriptional factors NFATc1 and c-Fos. Moreover, Scin-induced osteogenesis outweighed osteoclastogenesis in defective femur in vivo. The results of the analysis of Micro-CT confirmed these findings. Overall, Ccs influenced the development of DDH by promoting osteogenesis and cartilage degradation. In addition, Scin played a vital role in the development of DDH., (Copyright © 2017 Elsevier Inc. All rights reserved.)

Background: Because the use of magnetic resonance imaging is still not universal for the patients with developmental dysplasia of the hip patients, orthopaedists do not generally distinguish widened joint spaces which are "empty" after primary treatment (and therefore still reducible), from those which are filled and much more difficult to treat. To date no studies have focused on the latter hips. We treated and observed the outcomes for 19 hips which showed filled joint spaces after primary treatment., Methods: We retrospectively reviewed 19 cases of developmental dysplasia of the hip: (1) who showed a widened joint space on radiographs after primary treatment; and (2) whose magnetic resonance imaging showed that the widened joint space was accompanied by acetabular cartilage hypertrophy and/or was filled with fibrous tissues. All patients were over 1 year old at the time of primary reduction (reduction was closed in 4 patients, open in 6, and open with pelvic osteotomy in 9). Thirteen patients received at least 1 secondary treatment. Final results were classified using a modified Severin classification., Results: Final outcomes were satisfactory in 10 (52.6%) and unsatisfactory in 9 (47.4%). The widened joint spaces gradually filled with bone, resulting in a shallow acetabulum in the patients with unsatisfactory results. Of 9 patients who underwent combined pelvic osteotomy at the time of primary reduction, results were satisfactory in 6 (66.7%), whereas all patients who had only closed or open primary reduction had unsatisfactory results., Conclusions: Combined pelvic osteotomy at the time of primary reduction is advisable in hips with widened joint spaces. However, hips with filled joint spaces after primary treatment often have unsatisfactory results even after additional pelvic and/or femoral osteotomy., Level of Evidence: Level IV-prognostic study.

Background: Developmental dysplasia of the hip (DDH) is a common pathological condition of the musculoskeletal system in infants which results in a congenital and developmental malformation of the hip joint. DDH is a spectrum of pathologies affecting the infant hip ranging from asymptomatic subtle radiographic signs through mild instability to frank dislocations with acetabular dysplasia. A Saudi family with three affected individuals with DDH was identified and genetic analysis was performed to detect the possible genetic defect(s) underlying DDH in the affected members of the family., Methods: We performed whole genome genotyping using Illumina HumanOmni 2.5 M array and whole exome sequencing (WES) using Nextera Rapid capture kit and Illumina NextSeq500 instrument in four individuals of a family with DDH., Results: SNP data analysis did not identify any runs of homozygosity and copy number variations. Identity-by-descent (IBD) analysis on whole genome genotyping data identified a shared haplotypes on chromosome 1 in affected individuals. An analysis of the WES data identified rare heterozygous variants in HSPG2 and ATP2B4 genes in the affected individuals. Multiple prediction software predicted that the variants identified are damaging. Moreover, in silico analysis showed that HSPG2 regulates ATP2B4 expression using a variety of transcription factors., Conclusion: Our results indicate that there might be a functional epistatic interaction between HSPG2 and ATP2B4, and DDH in the family studied is due to a combined effect of both variants. These variants are also present in the asymptomatic mother suggesting that the variants in HSPG2 and ATP2B4 are incompletely penetrant. This study provides the first evidence of digenic inheritance of DDH in a family and extends the spectrum of genetic heterogeneity in this human disorder.

Developmental dysplasia of the hip (DDH) is a developmental disorder that has long-term chronic pain and limited hip joint mobility as major pathological characteristics. This study aims to access the association between the development of DDH and cartilage metabolic disorders. Cartilage tissue samples were acquired from patients with DDH, osteoarthritis (OA) and femoral neck fracture. The proteoglycan level was evaluated by safranin O-fast green, toluidine blue and hematoxylin-eosin (HE) staining. The levels of collagen-II (Col-II), collagen-X (Col-X) and metal matrix proteinase-13 (MMP-13) were evaluated by immunohistochemistry (IHC) and Western blotting analysis. The morphologic evaluation of cartilage was conducted by transmission electron microscopy (TEM). Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to detect the mRNA level of aggrecan, Col-II, Col-X and MMP-13. The aggrecan level in the cartilage matrix was significantly decreased in DDH patients by safranin O-fast green and toluidine blue staining in comparison with that in the OA and control groups. In contrast with the OA group, the Col-II expression was reduced while the MMP-13 expression increased in DDH patients, as shown by IHC and Western blotting analysis. The collagenous fibrils in cartilage of DDH patients appeared significantly sparse and disordered in the TEM analysis. In DDH patients, the mRNA expression levels of Col-II and aggrecan were markedly reduced, while the mRNA expression of Col-X was markedly increased, compared with the OA patients. There is severe articular cartilage degeneration in DDH patients. This observation provides us with new insight into cartilage metabolic regulation in DDH. © 2017 IUBMB Life, 69(3):179-187, 2017., (© 2017 International Union of Biochemistry and Molecular Biology.)

Objective To evaluate the effect of dynamic long leg casting in paediatric patients with developmental dysplasia of hip (DDH) diagnosed at 12-18 months. Methods The adductor tenotomy, closed reduction, and dynamic long leg casting method was adopted to treat paediatric patients with DDH. The hips were divided into four groups according to the Tonnis radiographic dislocation classification. Groups were also classified according to the baseline acetabular index (AI): 30°-35°, 36°-40°, and > 40°. The outcomes of the reductions were evaluated according to McKay's hip function criteria and Severin's radiological criteria. Results A total of 246 patients (339 hips) had complete follow-up data. After 3 months of orthosis fixation, the results were satisfactory in 264 hips (77.88%). Hip function was rated as 'excellent' or 'good' in 43 of 51 (84.31%) Tonnis type 1 hips, 125 of 155 (80.65%) type 2 hips, 70 of 90 (77.78%) type 3 hips, and 34 of 43 (79.07%) type 4 hips. The higher the baseline AI, the lower the rates of 'excellent' and 'good' hip function. Favourable radiological results (Severin types I and II) were found in 266 of 339 (78.47) hips. Conclusions Dynamic long leg casting is an effective method for treating patients with DDH aged 12-18 months at diagnosis.

Objectives: This study aims to investigate the effects of surgical approach on the clinical and radiological outcomes, the incidence of avascular necrosis (AVN), and the need for revision surgery in children undergoing open reduction via medial or anterior approach for developmental dysplasia of the hip (DDH)., Patients and Methods: Forty-three hips of 36 patients (9 males, 27 females; mean age 13.8 month; range 6 to 18 months) treated for DDH, followed-up regularly for at least four years between January 1997 and December 2010, and who were aged five or above in the final control were included in this retrospective study. Patients were divided into two groups according to surgical approaches. Group 1 consisted of 21 hips of 19 patients who underwent open reduction through medial approach. Group 2 consisted of 22 hips of 17 patients who underwent open reduction through anterior approach. Groups were compared in terms of clinical and radiological outcomes as well as the incidence of AVN and the need for revision surgery., Results: There was no statistically significant difference between the groups with respect to clinical and radiological outcomes (p=0.407 and p=0.661, respectively). Similarly, there was no statistically significant difference between the groups in terms of AVN incidence and need for revision surgery (p=0.993 and p=0.170, respectively). On the other hand, acetabular index improved significantly in both groups at follow-up., Conclusion: This study showed that open reduction via medial or anterior approach in DDH has similar clinical and radiological results, significant improvement was achieved in the acetabular index with both approaches, and no significant difference was present in the incidence of AVN and the need for revision surgery between the groups.

Purpose: To identify demographic and morphologic factors associated with the severity of intra-articular lesions in patients with severe hip dysplasia., Methods: One hundred twenty-one patients (134 hips) with symptomatic hip dysplasia were retrospectively reviewed. The cartilage and labral lesions were scored according to the Outerbridge and the original classification systems, respectively. The association of the cartilage and labrum scores with patient demographics (age, gender, body mass index, bilateral hip dysplasia, and treatment history for developmental hip dislocation) and morphologic factors (the lateral center-edge angle, Sharp angle, acetabular index, acetabular head index, acetabular depth ratio, Shenton line disruption, roundness index of the femoral head, and femoral neck shaft angle) were determined using a multiple linear regression analysis., Results: The cartilage and labral scores were significantly associated with radiographic osteoarthritis; however, these scores showed wide distribution among hips with equivalent degrees of radiographic osteoarthritis. Age (38.4 ± 12.8 years) (P < .001), lateral center-edge angle (0.2 ± 9.0°) (P = .014), acetabular head index (54.4 ± 9.1%) (P = .001), and the roundness index of the femoral head (55.6 ± 4.6%) (P = .022) were identified as independent factors associated with the cartilage score. Age (P < .001), having a medical history of developmental hip dislocation (P = .002), acetabular index (27.8 ± 6.8°) (P = .011), and the roundness index of the femoral head (P = .022) were identified as independent factors associated with the labral score., Conclusions: Our findings suggest that the morphologic factors responsible for severe intra-articular lesions differ for cartilage degeneration and labral tears in patients with severe hip dysplasia. Decreased acetabular coverage of the femoral head was responsible for cartilage degeneration severity, whereas an increased acetabular index was responsible for labral tear severity., Level of Evidence: Level III, diagnostic study., (Copyright © 2016 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)

Aims: This study compared the long-term results following Salter osteotomy and Pemberton acetabuloplasty in children with developmental dysplasia of the hip (DDH). We assessed if there was a greater increase in pelvic height following the Salter osteotomy, and if this had a continued effect on pelvic tilt, lumbar curvature or functional outcomes., Patients and Methods: We reviewed 42 children at more than ten years post-operatively following a unilateral Salter osteotomy or Pemberton acetabuloplasty. We measured the increase in pelvic height and the iliac crest tilt and sacral tilt at the most recent review and at an earlier review point in the first decade of follow-up. We measured the lumbar Cobb angle and the Short Form-36 (SF-36) and Harris hip scores were collected at the most recent review., Results: During the first decade of follow-up, there was a greater increase in pelvic height in the children who had a Salter osteotomy (Salter, 10.1%; Pemberton, 4.3%, p < 0.001). The difference in the increase in pelvic height was insignificant at the most recent review (Salter, 4.4%; Pemberton, 3.1%, p = 0.249). There was no significant difference between the two groups for the lumbar Cobb angle, (Salter, 3.1°; Pemberton, 3.3°, p = 0.906). A coronal lumbar curve was seen in 41 children (97%), 30 of these had a compensatory curve. Sacral tilt was the radiographic parameter for pelvic imbalance that correlated most with the lumbar Cobb angle (Pearson correlation co-efficient 0.59). The Harris hip score and SF-36 were good and showed no differences between the two groups., Conclusion: In the long-term, we found no difference in the functional results or pelvic imbalance between Salter osteotomy and Pemberton acetabuloplasty in the management of children with DDH. Cite this article: Bone Joint J 2016;98-B:1145-50., (©2016 The British Editorial Society of Bone & Joint Surgery.)

The purpose of this study was to investigate the indications, surgical technique, and the clinical effects of arthroscopic-assisted treatment of irreducible developmental dislocation of the hip by mid-term follow-up. Arthroscopic-assisted surgeries were performed on 40 children (52 hips) between January 2005 and December 2009. Anterior and antero-superior greater trochanter portals were used in these treatments. Spica cast and abduction splint were applied for 3 months postoperatively. The follow-up was conducted on every 3 months postoperatively. During 12-month follow-up, a secondary treatment such as acetabuloplasty and/or femoral osteotomy (shortening, varus, and derotation) was applied if the acetabular angle was greater than 25°. The pelvic acetabular angle, Mckay and Severin score were evaluated every 6 months in all children. With 36 to 96 months (average 71 months) follow-up, 35 children (44 hips) were successfully followed up with complete case data while 5 children unsuccessfully. According to Tönnis classification, there were 5 grade 1 hips, 14 grade 2 hips, 14 grade 3 hips, 11 grade 4 hips, in which 3 children (4 hips) were failed in arthroscopic reduction and femoral head avascular necrosis occurred in 2 children (4 hips). According to Mckay standard, the good rate is 100%. According to Severin standard, the good rate is 84.1%. Arthroscopic assisted treatment is an effective way of reduction of the irreducible hip. Compared with the open reduction, arthroscopic treatment combined with acetabuloplasty and/or femoral osteotomy has advantages of less trauma and better function preservation.

Lon protease is a nuclear-encoded, mitochondrial ATP-dependent protease highly conserved throughout the evolution, crucial for the maintenance of mitochondrial homeostasis. Lon acts as a chaperone of misfolded proteins, and is necessary for maintaining mitochondrial DNA. The impairment of these functions has a deep impact on mitochondrial functionality and morphology. An altered expression of Lon leads to a profound reprogramming of cell metabolism, with a switch from respiration to glycolysis, which is often observed in cancer cells. Mutations of Lon, which likely impair its chaperone properties, are at the basis of a genetic inherited disease named of the cerebral, ocular, dental, auricular, skeletal (CODAS) syndrome. This article is part of a Special Issue entitled 'EBEC 2016: 19th European Bioenergetics Conference, Riva del Garda, Italy, July 2-6, 2016', edited by Prof. Paolo Bernardi., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Developmental dysplasia of the hip (DDH) is one of the most common skeletal anomalies. DDH encompasses a spectrum of the disorder ranging from minor acetabular dysplasia to irreducible dislocation, which may lead to premature arthritis in later life. Involvement of genetic factors underlying DDH became evident when several studies reported chromosomal loci linked to DDH in families with multiple affected individuals. Moreover, using association studies, variants in genes involved in chondrogenesis and joint formation have been shown to be associated with DDH. At least, one study identified a pathogenic variant in the chemokine receptor gene in DDH. No genetic analysis has been reported or carried out in DDH patients from the Middle East. Here, we review the literature related to genetics of DDH and emphasized the usefulness of new generation technologies in identifying genetic variants underlying DDH in consanguineous families., (© 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: The morphologic characteristics of the labrum in patients with symptomatic acetabular dysplasia have been described to some extent in smaller retrospective series, but the need remains to further define these disease characteristics and their importance as a diagnostic feature of hip instability., Purpose: To (1) characterize the morphologic characteristics of the labrum in patients with symptomatic acetabular dysplasia and (2) test the relationships between specific labral variants, severity of dysplasia, and duration of symptoms., Study Design: Cross-sectional study; Level of evidence, 3., Methods: Thirteen surgeons from 10 centers enrolled patients undergoing periacetabular osteotomy (PAO) for symptomatic acetabular dysplasia from 2008 to 2014. Patient demographics, presenting characteristics, preoperative radiographic data, operative data, and intraoperative findings were prospectively collected and retrospectively reviewed., Results: A total of 942 patients (972 hips) met the initial inclusion criteria, with a mean age of 25.2 years (range, 9-51 years; 84% female, 16% male). In addition to having PAO, 52.6% of hips had an anterior arthrotomy and 19.8% had a hip arthroscopy either to perform an osteochondroplasty of the femoral head-neck junction or to address labral pathologic changes. Of these 553 hips in which the labrum was visualized, labral morphologic status was graded as hypertrophic in 50%, normal in 45%, hypoplastic in 4%, and ossified in less than 1%. Decreased lateral center-edge angle and anterior center-edge angle and increased acetabular inclination were associated with labral hypertrophy, but chronicity of symptoms was not. Of the 553 hips, 64% had tears of the labrum, with the majority being degenerative-type tears., Conclusion: Labral pathologic changes are common in patients with symptomatic acetabular dysplasia. Labral hypertrophy, however, is not a universal finding, particularly in hips with mild dysplasia, and therefore should not be considered a reliable diagnostic criterion for instability., (© 2015 The Author(s).)

A physics-based computational model of neonatal Developmental Dysplasia of the Hip (DDH) following treatment with the Pavlik Harness (PV) was developed to obtain muscle force contribution in order to elucidate biomechanical factors influencing the reduction of dislocated hips. Clinical observation suggests that reduction occurs in deep sleep involving passive muscle action. Consequently, a set of five (5) adductor muscles were identified as mediators of reduction using the PV. A Fung/Hill-type model was used to characterize muscle response. Four grades (1-4) of dislocation were considered, with one (1) being a low subluxation and four (4) a severe dislocation. A three-dimensional model of the pelvis-femur lower limb of a representative 10 week-old female was generated based on CT-scans with the aid of anthropomorphic scaling of anatomical landmarks. The model was calibrated to achieve equilibrium at 90° flexion and 80° abduction. The hip was computationally dislocated according to the grade under investigation, the femur was restrained to move in an envelope consistent with PV restraints, and the dynamic response under passive muscle action and the effect of gravity was resolved. Model results with an anteversion angle of 50° show successful reduction Grades 1-3, while Grade 4 failed to reduce with the PV. These results are consistent with a previous study based on a simplified anatomically-consistent synthetic model and clinical reports of very low success of the PV for Grade 4. However our model indicated that it is possible to achieve reduction of Grade 4 dislocation by hyperflexion and the resultant external rotation., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Purpose: The purpose of this study was to describe the anatomy as seen arthroscopically, the role of the labrum and its relevance in luxation and reduction procedures, and secondary changes to the cartilaginous acetabular roof and to determine the main obstacles preventing reduction of dislocated hips in infants and young children., Methods: A specialized pediatric medial approach to hip arthroscopy was performed on 25 hip joints in 21 patients younger than 4 years of age. The arthroscopic procedure was conducted using a 2.7-mm cannulated instrument. A subadductor portal was used for the 70° arthroscope, and a high anterolateral portal served as a working portal. The anatomic findings of the individual hip joints were recorded. We examined the femoral head, the teres ligament, the transverse ligament, the acetabulum, and the acetabular labrum. The obstacles preventing reduction were successively resected., Results: An arthroscopic investigation of all major structures and arthroscopic reduction was possible in 25 hip joints. A hypertrophic teres ligament was present in 23 of the 25 hips. Capsular constriction prevented reduction in 22 of the 25 hips. The acetabular labrum was not inverted in any of the examined hip joints and was also never an obstacle to reduction. Secondary changes to the cartilaginous preformed acetabular roof were present in 10 hips., Conclusions: We have shown that arthroscopy of a developmentally dislocated hip can be safely performed using the subadductor portal. Through this arthroscopic approach, we were able to identify the previously described pathologic structures-the limbus, neolimbus, pulvinar, hypertrophic teres ligament, and capsular constriction. The capsule was the most common block to reduction, followed by the teres ligament. Successful reduction can be achieved by removal of intra-articular tissues, the pulvinar, and the teres ligament, and nearly always a capsular release. The limbus and neolimbus were not factors in achieving reduction in our series., Level of Evidence: Level IV, case series., (Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.)