Introduction. There is little evidence surrounding the clinical implications of a diagnosis of IIa hip dysplasia with no consensus as to its efficacy as a predictor pathological dysplasia or treatment. Therefore, we evaluated the importance of categorising 2a hip dysplasia in to 2a- and 2a+ to better understand the clinical outcomes of each. Methods. A 9-year retrospective cohort study of patients with a diagnosis of type IIa hip dysplasia between 2011 – 2020 (n=341) in our centre. Ultrasound scans were graded using Graf's classification, assessment of management and DDH progression was completed through prospective data collection by the authors. Results. The prevalence of IIa hip dysplasia within our population was 6.7/1000 live births. There was significantly higher incidence of treatment in the IIa- (31.4%, n=17/54) group when compared to the 2a+ group (10%, n=28/287), (p<0.01). In those that had an abnormality (torticollis and/or foot abnormality) treatment rates (24% n=7/29) were significantly (p<0.05) higher than those without anatomical abnormality (15%, n=48/312). Conclusion. This study has demonstrated the significant clinical impact of a IIa- diagnosis on progression to pathological dysplasia and therefore higher rates of treatment in IIa- hips. Furthermore, we have demonstrated the importance of detection of IIa hips through a national screening program, to allow for timely intervention to prevent missing the acetabular maturation window. Therefore, it is our recommendation that all patients with additional anatomical abnormalities and those with a diagnosis of type IIa- hip dysplasia be considered for immediate treatment or urgent follow up following their diagnosis to prevent late conservative intervention

Developmental Dysplasia of the Hip (DDH) is the most common orthopaedic disorder in newborns. Whilst the Pavlik harness is one of the most frequently used treatments for DDH, there is immense variability in treatment parameters reported in the literature and in clinical practice, leading to difficulties in standardising teaching and comparing outcomes. In the absence of definitive quantitative evidence for the optimal Pavlik harness management strategy in DDH, we addressed this problem by scientifically obtaining international expert-based consensus on the same. An initial list of items relevant to Pavlik harness treatment was derived by systematic review of the literature according to PRISMA criteria and reviewed by two expert clinicians in DDH management. Delphi methodology was used to guide serial rounds of surveying and feedback to content matter experts from the International Hip Dysplasia Institute (IHDI), a collaborative group of paediatric orthopaedic surgeons with expertise in the management of DDH. Rounds of surveying continued in the same manner until consensus was reached. Importance ratings were derived from each round of surveying by calculating median score responses on the 5-point Likert scale for each item. Items requiring clarification or those with a median score of below 4 (“agree”) were modified as needed prior to each subsequent round. Consensus was considered reached when 90% or more of the items had an interquartile range (IQR) of ≤ 1. This value indicates low sample deviation and is accepted as having achieved consensus. This was followed by a corroboration of face validity to derive the final set of management principles. The literature search and expert review identified an initial list of 66 items in 8 categories relevant to Pavlik harness management. Four rounds of structured surveying were required to reach consensus. Following a final round of face validity, a definitive list of 33 items in 8 categories met consensus by the experts. These items were tabulated and presented as “General Principles of Pavlik Harness Treatment for DDH” and “Pavlik Harness Treatment by Severity of Hip Dysplasia”. Furthermore, highly contentious items were identified as important future areas of study and will be discussed. We have developed a comprehensive set of principles derived by expert consensus to assist clinicians, and for use as a teaching resource, in the non-operative management of DDH using the Pavlik harness. We have gained consensus on both the general principles of Pavlik harness treatment as well as the detailed treatment of hip subtypes seen across the spectrum of pathology of DDH. Furthermore, this study has also served to generate a list of the most controversial areas in the non-operative management of DDH which should be considered high priority for future study to further refine and optimise the outcomes of children with developmental hip dysplasia

Total hip arthroplasty (THA) is an effective operation for patients with hip osteoarthritis; however, patients with hip dysplasia present a particular challenge. Our novel study examined the effect of robotic-assisted THA in patients with hip dysplasia.. Nineteen patients at two centers presented with hip dysplasia. We found that components were placed according to the preoperative plan, there was a significant improvement in the modified Harris Hip Score from 31 to 84 (p<0.001), an improvement in hip range of motion (flexion improvement from 66 º to 91º, p<0.0001), a significant correction of leg length discrepancy (17.5 vs. 4 mm, p<.0002), and no short-term complications.. Robotic-assisted THA can be a useful method to ensure adequate component positioning and excellent outcomes in patients with hip dysplasia

Aims. Use of videos for patient education has grown in popularity. Literature promotes the use of videos to provide clearer information to patients and families. Information to patients are often provided via leaflets. In our regional (Cwm Taf Morgannwg University Health board- CTM UHB) one stop clinic, we aimed to pilot the use of an educational video on developmental dysplasia of the hip (DDH) for parents and guardians and assess its usefulness. Methods. Parents and guardians of children being treated for DDH with Pavlick harness were invited to the partake in the pilot scheme. A short video provided by the ‘What? Why? Children in Hospital’ (WWCIH) organisation was shown on a tablet to parents and guardians. A ten question questionnaire was then provided post watching the video. The questionnaire consisted of short answer, multiple choice, and rating scale (1-10) questions. Results. 23 parents/guardians participated. All participants stated the video was of the right duration. Participants of all stages in the Pavlik harness journey found the videos helpful. All participants responded that they would recommend the video to other parents and guardians. 52%(n=12) suggested that the video would be most useful to watch after DDH is diagnosed but before starting treatment. Participants also provided feedback on how to improve the videos such as inclusion of detailed explanations about the harness. Conclusion. The use of an educational video for parents/guardians with children diagnosed with DDH is beneficial, with all participants finding it useful. Other centres could adopt the use of educational videos for newly diagnosed DDH children's families, prior to starting treatment with the Pavlick harness

Introduction. Leg length discrepancy (LLD) in patients with unilateral developmental dysplasia of the hip (DDH) can be problematic for both patients and surgeons. Patients can acquire gait asymmetry, back pain, and arthritis. Surgical considerations include timing of correction and arthroplasty planning. This study audits standing long leg films performed at skeletal maturity in our patients. The aim of this study is to identify if surgical procedure or AVN type could predict the odds of needing an LLD Intervention (LLDI) and influence our surveillance. Materials and Methods. Hospital database was searched for all patients diagnosed with DDH. Inclusion criteria were patients with appropriately performed long leg films at skeletal maturity. Exclusion criteria were patients with non DDH pathology, skeletally immature and inadequate radiographs. All data was tabulated in excel and SPSS was used for analysis. Traumacad was used for measurements and AVN and radiologic outcome grades were independently classified in duplicate. Results. 110 patients were identified. The mean age of follow-up was 15 years with final average LLD of 1mm(±5mm). The DDH leg tended to be longer and length primarily in the femur. 31(28.2%) patients required an LLDI. 19 Patients had a final LLD >1.5cm. There was no statistical significant difference in the odds of needing an LLDI by type of surgical procedure or AVN. AVN type 4 was associated with greatest odds of intervention. The DDH leg was more likely to require ipsilateral epiphysiodesis or contralateral lengthening in Type 1 and 2 AVN. Conclusions. The DDH leg tends to be longer, leg lengths should be monitored, and leg length interventions are frequently required irrespective of previous DDH surgical procedure or the presence of AVN

Introduction. Developmental dysplasia of the hip (DDH) can be managed through a variety of different surgical approaches from closed reduction to simple tenotomies of the adductors and through to osteotomies of the femur and pelvis. The rate of redislocation following open reduction for the treatment of DDH may be affected by the number of intraoperative surgeons. Materials and methods. We performed a retrospective cohort analysis of 109 patients who underwent open reduction with or without bony osteotomies as a primary intervention between 2013 and 2023. We measured the number of redislocations and number of operating surgeons (either 1 or 2 operating surgeons) to assess for any correlation. 109 patients were identified and corresponded to 121 primary hip operations, the mean age at operation was 82.2 months (range 6 to 739 months). During the 10-year period 7 hip redislocations were identified. Results. Of the 7 redislocated hips, the rate of redislocation was found to be higher in patients who had undergone surgery via a single surgeon (5 redislocations) compared to the dual surgeon cohort (2 redislocations), though this did not reach statistical significance. Redislocation was more common in female patients and right laterality 7.2% and 8.7% respectively, though this again did not reach statistical significance. Conclusions. We conclude that a single surgeon approach, female gender and right laterality are potential risk factors for redislocation following open reduction. Further investigation utilising a larger sample size would be required to appropriately explore these potential risk factors further

Developmental dysplasia of the hip (DDH) is the most common paediatric hip condition and is a major cause of hip replacement or osteoarthritis in young adults. Due to potential impact on quality of life, every child is checked at birth for unstable hips. Should instability be detected, or the infant has other DDH risk factors, they are referred for an ultrasound exam and orthopaedic surgeon consultation. Since the implementation of a DDH screening program at our institution, the Radiology Department has seen a dramatic increase in hip ultrasounds performed. While helping prevent the complications of missed DDH diagnoses, this program has placed strain on radiology resources, and often families must attend multiple appointments before receiving a diagnosis and beginning treatment. To mitigate this, we have implemented a pilot point-of-care DDH clinic, where an ultrasound technician performs hip ultrasound exams using a portable ultrasound in the orthopaedic clinic in conjunction with surgeon consultation. The aim of this clinic is to enable diagnosis and treatment in one appointment, reduce referral-to-treatment delays, wait times, and decrease costs and travel time for families while also alleviating strain on radiology resources. A point-of-care DDH test clinic was implemented in the Orthopaedic Department at our institution. Patients referred with suspected/confirmed DDH attended a single orthopaedic clinic appointment. An ultrasound technician was present to perform scans in conjunction with the orthopaedic surgeon's clinical assessment. Surveys were distributed at the end of the appointment to collect feedback on the family's satisfaction with the program, as well as other pertinent demographic information (i.e. occupation, geographic location, travel time to hospital). To date, 40 patients have attended the pilot clinic. Families spent an average 61.3 minutes (range 15–420 minutes) traveling to the hospital for an appointment (122.6 minutes round-trip). This program reduced the number of hospital visits for DDH screening from three (initial consultation, radiology, follow-up) to one per patient, saving an average 245.2 minutes of travel time to/from the hospital per family. Appointment time averaged 35.9 minutes and families rated their satisfaction with appointment length an average of 9.6/10 (35/40 families rated satisfaction 10/10, 1 = very unsatisfied, 10 = very satisfied). Additionally, 33/40 families were also asked to rate their satisfaction with check-in/check-out processes (average 9.4/10), ultrasound screening (average 9.9/10), and time with specialist (average 9.9/10). Satisfaction scores did not differ based on variables such as survey taker's gender, occupation, or geographic location. The pilot point-of-care ultrasound DDH clinic has considerably reduced the number of clinic visits and travel time for families, reduced aggregate clinic wait times, and has resulted in high family satisfaction. This specialized clinic may have potential to free up hospital staff time and resources, possibly decreasing wait times in other clinical areas, ultimately improving quality of care for patients and families across our institution

Debate currently exists regarding the economic viability for screening for developmental dysplasia of the hip in infants. A retrospective study of infant hip dysplasia over the period of 1998–2008 (36,960 live births) was performed to determine treatment complexity and associated costs of disease detection and hospital treatment, related to the age at presentation and treatment modality. 179 infants (4.8/1000) presented with hip dysplasia. 34 infants presented late (>3 months of age) and required closed or open reduction. 145 infants presented at <3 months of age, 14 of whom failed early pavlik harness treatment. A detailed cost analysis revealed:. 131 early presenters with successful management in a pavlik harness at a cost of £601/child. 34 late presenters who required surgery (36 hips, 19 closed/ 17 open reductions, 1 revision procedure) at a cost of £4352/child. 14 early presenters with failed management in a pavlik harness requiring more protracted surgery (18 hips, 4 closed/ 14 open reductions, 7 revision procedures) at a cost of £7052/ child. Late detection causes increased treatment complexity and a seven-fold increase in the short-term costs of treatment, compared to early detection and successful management in a pavlik harness. However improved strategies are needed for the 10% of early presenting infants who fail pavlik harness treatment and require the most complex and costly interventions

Laterality and bilaterality have been reported as prognostic variables in DDH outcomes. However, there is little clarity across the literature on the reporting of laterality in developmental dysplasia of the hip (DDH) due to the variability in severity of the condition. It is widely accepted that the left hip is most frequently affected; however, the true incidence of unilateral left, unilateral right and bilateral cases can be hard to quantify and compare across studies. The purpose of this study was to examine laterality accounting for graded severity in a multicentre, international prospective observational study of infants with hip dysplasia in order to demonstrate the complexity of this issue. A multicentre, prospective database of infants diagnosed with DDH between the ages of 0 and 18 months was analysed from 2010 to April 2015. Patients less than six months were enrolled in the study if at least one hip was frankly dislocated. Patients between 6 and 18 months were enrolled if they had any form of hip dysplasia. Each hip was classified as reduced, dysplastic, dislocatable/subluxable, dislocated reducible or dislocated irreducible. Baseline diagnosis was used to classify patients into a graded laterality category accounting for hip status within the DDH spectrum. A total of 496 patients were included in the analysis; 328 were <6 months old at diagnosis and 168 were between 6 and 18 months old. Of these patients, 421 had at least one frankly dislocated hip. Unilateral left hip dislocations were most common, with 223 patients, followed by unilateral right and bilateral dislocations with 106 and 92 respectively. Stratifying these patients based on status of the contralateral hip, 54 unilateral left and 31 unilateral right dislocated patients also had a dysplastic or unstable contralateral hip. There were significantly fewer bilateral patients in the 6–18 month group (p=0.0005). When classifying laterality by affected hip, bilaterality became the predominant finding, comprising 42% of all patients. The distribution of unilateral left, unilateral right and bilateral cases was greatly impacted by the method of classification. Distinct patterns were seen when considering dislocated hips only, or when considering both dislocated and dysplastic/unstable hips. Findings from this multicentre prospective study demonstrate the necessity to account for the graded severity in hip status when reporting DDH laterality. In order to accurately compare laterality across studies, a standardised, comprehensive classification should be established, as contralateral hip status may impact prognosis and treatment outcomes

Hip dysplasia represents a wide spectrum of disease, and interest in the treatment of the disorder has increased with the development of newer surgical techniques and a greater understanding of young adult hip disorders. National hospital episode statistics (HES) were studied from 1999 to 2010. This data remains the current best source of information on surgical procedures outside of dedicated registries. Age stratified data was analysed for 7 separately coded operations for the treatment of hip dysplasia. Overall in the paediatric population there were 898 procedures in 2010 compared to 793 procedures in 2000, but with no detectable trend across that period. Equally, there were no great fluctuations in the small numbers of arthroplasty procedures recorded in either the paediatric or adult populations. There was, however, a clear increase in surgery being performed in adult patients. 210 primary pelvic osteotomies were performed in 2010, compared with only 77 in 2000, with a noticeable increase from 2005 onwards. A similar trend in other extra-articular procedures is seen, rising from 2 to 55 per year over the period studied. Overall, the level of surgical intervention has steadily risen from 104 procedures in 2000 to 422 in 2010, representing a fourfold rise in the number of operations being performed for hip dysplasia in the adult population over an 11 year period. The reasons for this are unclear. It may reflect improvements in the ability to diagnose and intervene earlier to prevent disease progression, but further research is also needed to better define the aetiology underlying these cases that present to the hip surgeon later in life

Although there are several reports of excellent long-term survival after cemented total hip arthroplasty (THA), cemented acetabular components are prone to become loose when compared with femoral components. On the other hand, the survival of cementless acetabular components has been reported to be equal or better than cemented ones and the use of cementless acetabular components is increasing. However, most of the reports on survival after THA are for patients with primary hip osteoarthritis (OA) and there is no report of 20-year survival of cementless THA for patients with hip dysplasia. It is supposed to be more difficult to fix cementless acetabular components for OA secondary to hip dysplasia than primary OA. The purposes of this study were to review retrospectively the 20-year survival of cemented and cementless THA for hip dysplasia and to compare the effect of fixation methods on the long-term survival for patients with hip dysplasia. We retrospectively reviewed all patients with OA secondary to hip dysplasia treated with a cemented Bioceram hip system between 1981 and 1987, and a cementless cancellous metal Lübeck hip system between 1987 and 1991. We excluded patients aged more than 60 years, males, and Crowe 4 hips. The studied subjects were 70 hips of cemented THA (Group-C) and 57 hips of cementless THA (Group-UC). Both hip implants had a 28-mm alumina head on polyethylene articulation. The mean age at operation was 50.5 years (range, 36–60 years) in Group-C and 50.0 years (range, 29–60 years) in Group-UC. The mean BMI was 23.2 kg/m. 2. in Group-C (range, 17.3–29.3 kg/m. 2. ) and 22.9 kg/m. 2. in Group-UC (range, 18.8–28.0 kg/m. 2. ). There were no significant differences in age and BMI between the two groups. The average follow-up period was 18.0 years in Group-C and 18.4 years in Group-UC. In Group-C, revision was performed in 33 hips due to aseptic cup loosening (30 hips), stem loosening (one hip), and loosening of both components (two hips). In Group-UC, revision was performed in 10 hips due to stem fracture secondary to distal fixation (4 hips), cup loosening (three hips), polyethylene breakage (two hips), and extensive osteolysis around the stem (one hip). The survival at 20 years regarding any revision as the endpoint was 51% in Group-C and 84% in Group-UC. This difference was significant using Log-rank test (P=0.006). The cup survival at 20 years was 54% in Group-C and 92% in Group-UC. This difference was also significant (P = 0.0003). The stem survival at 20 years was 95% in Group-C and 92% in Group-UC. This difference was not significant (P = 0.4826). Cementless THA showed a higher survival rate at 20 years for hip dysplasia than cemented THA because of the excellent survival of the acetabular component without cement. We conclude that cementless THA with the cancellous metal Lübeck hip system led to better longevity at 20 years than cemented THA with the Bioceram for patients with OA secondary to hip dysplasia

Background. It is technically challenging to restore hip rotation center exactly in total hip arthroplasty (THA) for patients with end-stage osteoarthritis secondary to developmental dysplasia of the hip (DDH) due to the complicated acetabular morphology changes. In this study, we developed a new method to restore hip rotation center exactly and rapidly in THA with the assistance of three dimensional (3-D) printing technology. Methods. Seventeen patients (21 hips) with end-stage osteoarthritis secondary to DDH who underwent THA were included in this study. Simulated operations were performed on 3-D printed hip models for preoperative planning. The Harris fossa and acetabular notches were recognized and restored to locate acetabular center. The agreement on the size of acetabular cup and bone defect between simulated operations and actual operations were analyzed. Clinical and radiographic outcomes were recorded and evaluated. Results. The sizes of the acetabular cup of simulated operations on 3-D printing models showed a high rate of coincidence with the actual sizes in the operations(ICC value=0.930) There was no significant difference statistically between the sizes of bone defect in simulated operations and the actual sizes of bone defect in THA(t value=0.03 P value=0.97). The average Harris score of the patients was improved from (38.33±6.07) preoperatively to the last follow-up (88.61±3.44) postoperatively. The mean vertical and horizontal distances of hip rotation center on the pelvic radiographs were restored to (15.12 ± 1.25 mm and (32.49±2.83) mm respectively. No case presented dislocation or radiological signs of loosening until last follow-up. Conclusions. The application of 3-D printing technology facilitates orthopedists to recognize the morphology of Harris fossa and acetabular notches, locate the acetabular center and restore the hip rotation center rapidly and accurately

Dynamic 2D sonography of the infant hip is a commonly used clinical procedure for developmental dysplasia of the hip (DDH) screening. It however has been found to be unreliable with some studies reporting associated misdiagnosis rates of up to 29%. In a recent systematic review, Charlton et al. examined dynamic ultrasound (US) screening for hip instability in the first six weeks after birth and found current best practices for such early screening techniques to be divergent between international institutions in terms of clinical scanning protocols. Such protocols include: the appropriate scanning plane and US probe position (e.g. coronal, transverse, lateral, anterior), DDH diagnostic metrics (e.g. femoral head coverage, alpha angle), appropriate patient age when scanning, and follow up procedures. To improve reliability of diagnosis and to help in standardizing diagnosis across different raters and health-centers, we propose an automated method for dynamically assessing hip instability using 3D US. 38 infant hips from 19 patients were scanned with B-mode 3D US by a paediatric orthopaedic surgeon and two technologists from the radiology department at a paediatric tertiary care centre. To quantify hip assessment, we proposed the use of femoral head coverage variability (ΔFHC3D) within 3D US volumes collected during a sequence of US scans (one at rest, and another with posterior stress applied to the joint as maneuvered during a dynamic assessment). We used phase symmetry image features to localize the ilium's vertical cortex and a random forest classifier to identify the location of the femoral head. The proposed ΔFHC3D provided good repeatability with an average test-retest ICC measure of 0.70 (95% confidence interval: 0.35 to 0.87, F(21,21) = 7.738, p<.001). The mean difference of ΔFHC3D measurements was 0.61% with a SD of 4.05%. Since the observed changes in ΔFHC3D start near 0% and range up to about 18% from stable to mildly unstable hips in this cohort, the mean difference and standard deviation of ΔFHC3D measurements observed suggest that the proposed metric and technique likely have sufficient resolution and repeatability to quantify differences in hip laxity. The long-term significance of this approach to evaluating dynamic assessments may lie in increasing early diagnostic accuracy in order to prevent dysplasia remaining undetected prior to manifesting itself in early adulthood joint disease

Avascular necrosis (AVN) of the femoral head is a potentially devastating complication of treatment for developmental dysplasia of the hip (DDH). AVN most commonly occurs following operative management by closed (CR) or open reduction (OR). This occurrence has frequently been examined in single centre, retrospective studies, however, little high-level evidence exists to provide insight on potential risk factors. The purpose of this observational, prospective multi-centre study was to identify predictors of AVN following operatively-managed DDH. A multi-centre, prospective database of infants diagnosed with DDH from 0–18 months was analyzed for patients treated by CR and/or OR. At minimum one year follow-up, the incidence of AVN (Salter criteria) was determined from AP pelvis radiographs via blinded assessment and consensus discussion between three senior paediatric orthopaedic surgeons. Patient demographics, clinical exam findings and radiographic data were assessed for potential predictors of AVN. A total of 139 hips in 125 patients (102 female, 23 male) underwent CR/OR at a median age of 10.4 months (range 0.7–27.9). AVN was identified in 37 cases (26.6% incidence) at a median 23 months post-surgery. Univariate logistic regression analysis comparing AVN and no AVN groups identified sex, age at diagnosis, age at surgery, pre-surgery IHDI grade and time between diagnosis and surgery as potential predictive factors. Specifically, male sex (OR 2.21 [0.87,5.72]), IHDI grade IV, and older age at diagnosis (7.4 vs. 9.5 months) and surgery (10.2 vs. 13.6 months) were associated with development of AVN. Likewise, increased time between diagnosis and surgery (2.9 vs. 5.5 months) was also associated with a higher incidence. No association was found with surgery type (CR vs. OR), pre-surgery acetabular index or surgical hip. Development of AVN occurred in 26.6% of hips undergoing CR or OR at a median 23 months post-surgery. Male sex, older age at diagnosis and surgery, dislocation severity and increased time between diagnosis and surgery were associated with AVN. Longer-term follow-up and larger numbers will be required to confirm these findings. Early outcomes from this prospective patient cohort suggest that AVN is an important complication of operative management for DDH, and appears to occur at a comparable rate whether the reduction is performed open or closed. Male patients may be more susceptible to developing AVN and merits further exploration. Potential predictive factors of older age and length of time between diagnosis and surgery emphasize the importance of early detection and treatment to minimize complications and optimize outcomes

Introduction. Robotic-assisted hip arthroplasty helps acetabular preparation and implantation with the assistance of a robotic arm. A computed tomography (CT)-based navigation system is also helpful for acetabular preparation and implantation, however, there is no report to compare these methods. The purpose of this study is to compare the acetabular cup position between the assistance of the robotic arm and the CT-based navigation system in total hip arthroplasty for patients with osteoarthritis secondary to developmental dysplasia of the hip. Methods. We studied 31 hips of 28 patients who underwent the robotic-assisted hip arthroplasty (MAKO group) between August 2018 and March 2019 and 119 hips of 112 patients who received THA under CT-based navigation (CT-navi group) between September 2015 and November 2018. The preoperative diagnosis of all patients was osteoarthritis secondary to developmental dysplasia of the hip. They received the same cementless cup (Trident, Stryker). Robotic-assisted hip arthroplasty were performed by four surgeons while THA under CT-based navigation were performed by single senior surgeon. Target angle was 40 degree of radiological cup inclination (RI) and 15 degree of radiological cup anteversion (RA) in all patients. Propensity score matching was used to match the patients by gender, age, weight, height, BMI, and surgical approach in the two groups and 30 patients in each group were included in this study. Postoperative cup position was assessed using postoperative anterior-posterior pelvic radiograph by the Lewinnek's methods. The differences between target and postoperative cup position were investigated. Results. The acetabular cup position of all cases in both Mako and CT-navi group within Lewinnek's safe zone (RI: 40±10 degree; RA: 15±10 degree) in group were within this zone. Three was no significant difference of RI between Mako and CT-navi group (40.0 ± 2.1 degree vs 39.7± 3.6 degree). RA was 15.0 ± 1.2 degree and 17.0 ± 1.9 degree in MAKO group and in CT-navi group, respectively, with significant difference (p<0.001). The differences of RA between target and postoperative angle were smaller in MAKO group than CT-navi group (0.60± 1.05 degree vs 2.34± 1.40 degree, p<0.001). The difference or RI in MAKO group was smaller than in CT-navi, however, there was no significance between them (1.67± 1.27 degree vs 2.39± 2.68 degree, p=0.197). Conclusions. Both the assistance of the robotic arm and the CT-based navigation system were helpful to achieve the acetabular cup implantation, however, MAKO system achieved more accurate acetabular cup implantation than CT-based navigation system in total hip arthroplasty for the patients with OA secondary to DDH. Longer follow-up is necessary to investigate the clinical outcome

90% of young patients that develop DJD of the hip have an underlying structural problem, most frequently hip dysplasia. The structural problem results in decreased contact area, increased contact stresses about the anterior and lateral acetabulum and femoral head and results in labral pathology, early cartilage damage and if left untreated leads to end stage hip arthritis. Despite the optimism of alternative bearing surfaces and highly cross linked polyethylene, THA should still be discouraged in young patients. Many patients with symptomatic hip dysplasia in the absence of arthritis will benefit from joint preservation. The goal of treatment should be restoration of anatomy as close to normal as possible. The Bernese PAO is the preferred technique in many centres in North America and Europe because of its balance between minimal exposure, complications, and ability to provide optimal correction. The ideal patient for a PAO is young, has no arthritis, is not obese (BMI <30) and has poorly covered femoral head where congruency is possible. A PAO has advantages over other osteotomies and include: . 1). Performed through one incision without violation of the abductors. 2). Pelvic ring and an outlet, are not disrupted. 3). Posterior column is preserved. 4). Allow multidirectional correction. 5). Can perform capsulotomy to assess the labrum and check for impingement. The results of the osteotomy have been encouraging with up to 60% survivorship free from total hip arthroplasty at 20 years. Most studies show improvement in pain and function, improvement in radiographic coverage of the femoral head with no improvement in range of motion. Treatment should be individualised to each patient based on radiographic findings, age and cartilage status and restoration of anatomy as close to normal as possible should be the ideal treatment, most commonly in the form of a periacetabular osteotomy

Introduction. Acetabular dysplasia cause hip joint osteoarthritis(OA) by change hip mechanism. However, to our best knowledge, no studies have been published using prospectively collected data from asymptomatic young age volunteers, precise radiographic method. The purpose of this study is to evaluate the prevalence of hip dysplasia in asymptomatic Korean population as one of the most important risk factor of hip OA. Materials & Methods. From December 2014 to March 2015, we investigated prospectively collected retrospectively reviewed data of 200 asymptomatic volunteers 400 hips in age between 18 and 50 years recruited from our institution. Pelvic radiographs were taken and all radiographs were reviewed by 2 experienced orthopedic surgeons. Lateral center-edge angle(LCEA), Sharp angle, Tonnis angle and acetabular width-depth ratio were measured. We analyzed the statistical differences of these values between sex by Mann-Whitney U test and independent t-test. Pearson's correlation coefficient was used to measure the relationship between dysplasia parameters. Results. On the Pelvic AP view, 60 of the 400 hips (15%) were dysplastic hip as LCEA <20°. In 146 male hips, 17 hips (11.6%) were LCEA <20°. In 254 female hips, 43 hips(16.9%) were LCEA <20°. There was no strong correlation of LCEA with other measurements. Conclusion. There are large number of asymptomatic dysplastic hips in Asian population compared previously investigated

Developmental dysplasia of the hip (DDH) is a common risk factor of early osteoarthritis (OA), with insufficient coverage of the femoral head by the acetabulum which leads to excessive cartilage stresses in the hip joint. Knowledge of the molecular health of cartilage using MRI may diagnose and stage chondral disease, but more importantly allows for treatment stratification and prognostication. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is a validated MRI technique for detecting early loss of proteoglycan (PG). However, it requires an injection of contrast agent and exercise prior to the scan. MRI techniques such as T1ρ and T2 mapping have also been shown to be sensitive to early biochemical changes in cartilage but can be performed without any contrast injection. In this study we evaluate three quantitative MR techniques (dGEMRIC, T1ρ and T2 mapping) in patients with DDH. Our hypothesis is that both T1ρ and T2 correlate with dGEMRIC, and thus may be effective non-contrast based techniques for biochemical cartilage mapping in DDH hips. Seven informed and consented patients (mean age: 31.1 years) with DDH were enrolled in this IRB approved MRI study before surgery. DDH was defined as a lateral center-edge angle under 25º and acetabular index >13º on the plain x-ray. All subjects underwent two successive MRI sessions at 3T: In the first cartilage T1ρ and T2 mapping were performed. After leaving the scanner the subjects were injected with 0.4ml/kg Dotarem (i.v.), walked for 15min and rested for 25min before returning into the MRI. dGEMRIC (T1post) mapping was initiated approximately 45min after the injection. Image post-processing, registration and cartilage segmentation was performed with Matlab. The joint was subdivided into anterior and posterior regions in the sagittal plane and into lateral, intermediate and medial zones in the transverse plane, resulting in six region of interest (ROIs): antero-lateral, antero-intermediate, antero-medial, postero-lateral, postero-intermediate and postero-medial. The correlation between the dGEMRIC and T1ρ and dGEMRIC and T2 were evaluated using Spearman's Rho and tested for significance. The analysis of all six cartilage ROIs for all subjects resulted in a significant (p < 0 .001) negative correlation (Rho = −0.50) between the dGEMRIC index (T1post) and the T1ρ relaxation time. The dGEMRIC index and T2 correlated positive (Rho = 0.55) and significant (p < 0 .001). Although this pilot study has a small sample size a negative correlation between dGEMRIC and T1ρ was found in patients with DDH. Both methods are known to probe the PG content of cartilage, where a decreased PG content leads to lower dGEMRIC index and an increased T1ρ value. The correlation coefficient was moderate, but significant, which shows that T1ρ mapping as an effective tool to probe the cartilage PG content similar to dGEMRIC. A comparable, but positive correlation was found between dGEMRIC and T2. T2 is sensitive to the cartilage collagen content with a decreased T2 value in degenerated cartilage. In symptomatic DDH, where an onset of OA is assumed, both PG depletion and collagen decay are in progress and can be evaluated using these mapping techniques

Objectives. For patients with Developmental Dysplasia of the Hip (DDH) who progress to needing total joint arthroplasty it is important to understand the morphology of the femur when planning for and undertaking the surgery, as the surgery is often technically more challenging in patients with DDH on both the femoral and acetabular parts of the procedure. 1. The largest number of male DDH patients with degenerative joint disease previously assessed in a morphological study was 12. 2. In this computed tomography (CT) based morphological study we aimed to assess whether there were any differences in femoral morphology between male and female patients with developmental dysplasia undergoing total hip arthroplasty (THA) in a cohort of 49 male patients, matched to 49 female patients. Methods. This was a retrospective study of the pre-operative CT scans of all male patients with DDH who underwent THA at two hospitals in Japan between 2006–2017. Propensity score matching was used to match these patients with female patients in our database who had undergone THA during the same period, resulting in 49 male and 49 female patients being matched on age and Crowe classification. The femoral length, anteversion, neck-shaft angle, offset, canal-calcar ratio, canal flare index, lateral centre-edge angle, alpha angle and pelvic incidence were measured for each patient on their pre-operative CT scans. Results. Significant differences were found in femoral anteversion with a mean male anteversion of 22 ˚ (±14.2), compared to 30˚ (±15.5), in females (p=0.02, Confidence Interval (C.I.) 1.6 to 14.9, Figure 1), offset, with a mean male offset of 31 mm (±6.2), compared to 29 mm (±6.1) in females, (p=0.04, C.I: 0.2 to 4.8), and femoral length with a mean femoral length of 434 mm in males (±22.2), compared to 407 mm in females (±23.9), (p<0.001, C.I: 19.2 to 34.3, Figure 2). No significant differences between male and female patients were found for the other measurements. Discussion. This was the first study of this size assessing femoral morphology in male patients with DDH undergoing THA. Significant differences were found between male and female patients in femoral anteversion, length and offset. This should be taken into account when planning and performing THA in these patients. Based on the findings from this study, a more anteverted femoral neck can be expected at the time of surgery in a female patient with DDH undergoing total hip arthroplasty, compared to a male patient

Background. Total hip arthroplasty for Crowe type IV developmental dysplasia of the hip is a technically demanding procedure. Restoration of the anatomical hip center frequently requires limb lengthening in excess of 4 cm and increases the risk of neurologic traction injury. However, it can be difficult to predict potential leg length change, especially in total hip arthroplasty for Crowe type IV developmental hip dysplasia. The purpose of the present study was to better define features that might aid in the preoperative prediction of leg length change in THAs with subtrochanteric femoral shortening osteotomy for Crowe type IV developmental dysplasia of the hip. Patients and Methods. Primary total hip arthroplasties with subtrochanteric femoral shortening osteotomy were performed in 70 hips for the treatment of Crowe type IV developmental hip dysplasia. The patients were subdivided into two groups with or without iliofemoral osteoarthritis. Leg length change after surgery was measured radiographically by subtracting the amount of resection of the femur from the amount of distraction of the greater trochanter. Preoperative passive hip motion was retrospectively reviewed from medical records and defined as either higher or lower motion groups. Results. The preoperative flexion of patients without iliofemoral osteoarthritis was significantly higher than for patients with iliofemoral osteoarthritis. All hips without iliofemoral OA had higher motion. The preoperative flexion in the higher motion group both with and without iliofemoral OA was significantly greater than in the lower group with iliofemoral OA (Figure 1). Leg length change in patients without iliofemoral osteoarthritis was significantly greater than with iliofemoral osteoarthritis (Figure 2), and the higher hip motion group had greater leg length change in THA than the lower motion group. No clinical evidence of postoperative neurologic injury was observed in patients with iliofemoral OA. Postoperative transient calf numbness in the distribution of the sciatic nerve was observed in 2 of 25 hips without iliofemoral OA (8.0%), however, no sensory and motor nerve deficit was observed. Discussion. The authors hypothesized that preoperative hip motion could affect soft tissue contractures, and our findings suggest that the soft tissues surrounding the hip joint with iliofemoral OA should be more contracted than the hip without OA. We also found leg length change in the higher motion group was greater than in the lower motion group. Previous studies reported limb lengthening in excess of 4 cm could increase the risk of nerve palsy. Transient calf numbness in the distribution of the sciatic nerve was observed in 2 hips without iliofemoral OA and their leg length change was not greater than 4 cm. Our findings suggest that hips without iliofemoral OA should be paid attention to protect the nerves from excessive elongation. The current study identifies several features that might help predict leg length change during the preoperative planning of total hip arthroplasty for Crowe type IV developmental hip dysplasia