Aims. When the present study was initiated, we changed the treatment for late-detected developmental dislocation of the hip (DDH) from several weeks of skin traction to markedly shorter traction time. The aim of this prospective study was to evaluate this change, with special emphasis on the rate of stable closed reduction according to patient age, the development of the acetabulum, and the outcome at skeletal maturity. Methods. From 1996 to 2005, 49 children (52 hips) were treated for late-detected DDH. Their mean age was 13.3 months (3 to 33) at reduction. Prereduction skin traction was used for a mean of 11 days (0 to 27). Gentle closed reduction under general anaesthesia was attempted in all the hips. Concurrent pelvic osteotomy was not performed. The hips were evaluated at one, three and five years after reduction, at age eight to ten years, and at skeletal maturity. Mean age at the last follow-up was 15.7 years (13 to 21). Results. Stable closed reduction was obtained in 36 hips (69%). Open reduction was more often necessary in patients ≥ 18 months of age at reduction (50%) compared with those under 18 months (24%). Residual hip dysplasia/subluxation occurred in 12 hips and was significantly associated with avascular necrosis (AVN) and with high acetabular index and low femoral head coverage the first years after reduction. Further surgery, mostly pelvic and femoral osteotomies to correct subluxation, was performed in eight hips (15%). The radiological outcome at skeletal maturity was satisfactory (Severin grades 1 or 2) in 43 hips (83%). Conclusions. Gentle closed reduction can be attempted in children up to three years of age, but is likely to be less successful in children aged over 18 months. There is a marked trend to spontaneous improvement of the acetabulum after reduction, even in patients aged over 18 months and therefore simultaneous pelvic osteotomy is not always necessary

Background: Screening modalities in early detection of DDH remain controversial worldwide despite of universal accessibility to ultrasound and despite of encouraging preliminary results reported about the Austrian and German general ultrasound screening programs. The goal of our investigations was to provide a long time survey on effects following the introduction of the ultrasound exam in prevention of DDH and to proof its beneficial medical and economic effects as well as to analyze possible adverse effects, when utilized by a general screening. Method: Nationwide data about ultrasound screening exams, sonographic follow up exams, frequencies of functional abductive treatment measures as well as hospitalizations due to DDH were requested by different Austrian health care providers. Through a representative recall over a time frame ranging partially back to 1980 a surveillance analysis is provided. The medical effectiveness of the screening was mainly assessed by the annual appearance of early late cases, representing open reductions (O.R.) upon the first two years of life. Other variables as the disease related incidence of age matched annual hospitalizations and the disease prevalence measured by non age matched hospitalizations in relation to the year specific population were analyzed. A cost benefit analysis was performed by comparing the treatment and diagnostic costs in the year before program start (1991) to the last year of surveillance (2004). Results: Since 1980 the functional treatment rate has continuously been reduced from approximately 12 percent to 3.23 percent in 2004. Early late cases (O.R.) due to DDH have been also diminished to an international competitive rate of 0.13 per 1000 newborns, while other age specific early surgical interventions could be almost eradicated. Current additional investments of the program figure only 16.94 € per newborn and embody approximately 1370 € per detection of one affected newborn. Control exams are contributing to roughly 25% of the calculated costs. Interpretation: By founding a nationwide program Austria has introduced a medically efficient screening modality to reduce early late cases and to limit treatment of DDH exposed children to less invasive measures by early diagnosis. In contrary to suspicions of possible adverse effects of such screening, overtreatment has been abandoned while the functional treatment rate has sunken to an acceptable level. Costs saving effects have been already realized on the treatment side. Further savings shall be realized by limiting an unacceptable rate of control exams

Aims. Early detection of developmental dysplasia of the hip (DDH) is associated with improved outcomes of conservative treatment. Therefore, we aimed to evaluate a novel screening programme that included both the primary risk factors of breech presentation and family history, and the secondary risk factors of oligohydramnios and foot deformities. Methods. A five-year prospective registry study investigating every live birth in the study’s catchment area (n = 27,731), all of whom underwent screening for risk factors and examination at the newborn and six- to eight-week neonatal examination and review. DDH was diagnosed using ultrasonography and the Graf classification system, defined as grade IIb or above or rapidly regressing IIa disease (≥4. o. at four weeks follow-up). Multivariate odds ratios were calculated to establish significant association, and risk differences were calculated to provide quantifiable risk increase with DDH, positive predictive value was used as a measure of predictive efficacy. The cost-effectiveness of using these risk factors to predict DDH was evaluated using NHS tariffs (January 2021). Results. The prevalence of DDH that required treatment within our population was 5/1,000 live births. The rate of missed presentation of DDH was 0.43/1000 live births. Breech position, family history, oligohydramnios, and foot deformities demonstrated significant association with DDH (p < 0.0001). The presence of breech presentation increased the risk of DDH by 1.69% (95% confidence interval (CI) 0.93% to 2.45%), family history by 3.57% (95% CI 2.06% to 5.09%), foot deformities by 8.95% (95% CI 4.81% to 13.1%), and oligohydramnios nby 11.6% (95 % CI 3.0% to 19.0%). Primary risk factors family history and breech presentation demonstrated an estimated cost-per-case detection of £6,276 and £11,409, respectively. Oligohydramnios and foot deformities demonstrated a cost-per-case detected less than the cost of primary risk factors of £2,260 and £2,670, respectively. Conclusion. The inclusion of secondary risk factors within a national screening programme was clinically successful as they were more cost and resource-efficient predictors of DDH than primary risk factors, suggesting they should be considered in the national guidance. Cite this article: Bone Jt Open 2023;4(4):234–240

The fibrocartilaginous labrum acetabulare enlarges the acetabular socket and contributes to the stability of the femoral head. In DDH the labrum is everted and pushed upward by the femoral head. In the dislocated hip the labrum is often inverted into the acetabular cavity and obstructs anatomic reduction. In the past, excision of the labrum was performed to allow the reduction of the femoral head. The aim of this study was to evaluate the position of the labrum in early detected decentered hips and its role in the early treatment of DDH. During the eleven-year period from 1992–2002, 21,709 neonates (43,418 hips) were examined both by ultrasound and by Ortolanis test to establish the diagnosis of DDH. According to Grafs classification the following hips were present: 298 type D-hips, 252 type IIIa, 4 type IIIb and 20 type IV. Therefore 431 of the patients (356 females and 75 males) showed 574 sonographically unstable hips affected by DDH (1.32%). Due to its echogenic structure, the fibrocartilaginous labrum is clearly visible by ultrasound. In type D, type IIIa, and type IIIb it was always located cranially to the femoral head; in type IV it was located medially to the femoral head. The average age of the children at the time of the diagnosis was 42 33 days (mean value SD). Ortolanis test was positive in 61 hips (10.63%) and negative in the remainder of the hips (89.37%). 21.5 % of the cases were diagnosed within the second week of life, 52.9 % between the third and the eighth week, and 25.5 % after the eighth week. The labrum was not inverted in any of these cases, nor was an open reduction necessary in order to remove it as an obstacle to the closed reduction. Only the ultrasound examination allowed the early diagnosis of the unstable decentered hips. The importance of the labrum decreases when an early diagnosis can be made and an early treatment can be performed

Introduction. Leg length inequality post total hip arthroplasty is a source of patient dissatisfaction. In adult DDH femoral length equality is assumed. Empirically, a longer femur has been observed on the affected side in the presence of unilateral DDH; restoration of the hip centre in this situation may lengthen the affected leg. Aim. Assessment of femoral length variation in adults with unilateral and bilateral DDH. Method. Retrospective observation study of 17 adults with unilateral and 7 adults with bilateral DDH. Femoral lengths assessed using CT measurements. Results. Unilateral DDH. The ipsilateral femur was longer in 11 patients (63%) The degree of femoral lengthening was between 5 and 10 mm. Bilateral DDH. The femur with the greater degree of DDH was longer by a mean of 7.5 19.3 mm . Conclusion. In the presence of DDH, asymmetry of femoral lengths is common and unpredictable. Careful femoral length assessment ( with CT leg lengths) is advised preoperatively in patients with DDH. This will alert the surgeon and patient to the possible risk of post operative ipsilateral leg lengthening

Introduction: Despite early screening, infants continue to present late ( > 4 months) with DDH. The impact of late diagnosis is significant. Established DDH causes significant morbidity and may have major medicolegal implications. Aim: To review the incidence of late presenting DDH nationally for a single year and assess the patterns of referral. To identify the reasons for the late presentation of DDH in the presence of early clinical screening. Methods: In a retrospective study all cases of late DDH presenting in 2004 were identified using inpatient database. Patient records were retrieved and data collected. Results: Fifty nine cases of DDH were diagnosed at greater than 4 months. There was an additional 26 cases of isolated acetabular dysplasia treated at greater than four months. The mean age of diagnosis was 14.6 months (range 4–72). Many of the late referrals had risk factors for DDH. Conclusion: Despite routine clinical screening at birth and six weeks, children continue to present with late DDH. This represents a significant workload for our tertiary unit

There is a very long way from diagnosis to treatment of the developmental dysplasia of the hip. Everything is complex: clinical examination is subtle and requires a long training. Treatment is not as simple as could be thought. The risks include approximate examinations and of standard, ready-made ones. The discussion has not been settled as to whether all children with hip instability can be clinically detected at birth. The complexity of the problem arises from the fact that only 10% of children who have instability at birth develop long-term problems if they are left untreated. It is well known, affirmed by several different studies that at birth the incidence of hip instability in approximately 1–4% of patients, with figure being higher in girls. There is also a consensus that a large majority of these unstable hips will become stable during the first few days of life, even without treatment. What is not known, however, is how many of those hip that become stable will become completely normal as the child grows. These two fundamental issues are of the utmost importance. They emphasize the significance of early examination (first 48 hours) in order to detect instability and employ careful follow-up of any newborn in whom hip instability has been identified. Some children are at particular risk of hip instability. Those infants are labeled as “high risk”. They include children born in families with hip instability, those presented by breech, first born children or products of oligohydramniotic pregnancies, particularly girls, those with the generalized joint laxity, those with torticollis and scoliosis, those with foot deformities and increased birth-weight over 4000g. Whilst all children should be screened at birth by a doctor experienced in clinical examination with particular attention directed to those children, who are considered high risk. It must be emphasized that clinical examination is the most important for the detection of hip instability in newborns. Clinical examination should be very delicate, gentle, based on feelings rather than signs. Clinically, hip instability can be divided into: 1. irreducible dislocation, 2. reducible dislocation, 3. dislocatability, 4. subluxability. The clinical tests of instability were described by Ortolani and Barlow. Fully dislocated irreducible hip is a very rare condition and may be associated with neuromuscular abnormality. It represents dislocation well before delivery. In this form acetabulum is vacant, femoral head palpable posteriorly. There are no singns of Ortolani and Barlow tests. We can only find the sings of “pump”, which means there exists a movement along the long axis of the leg. This is the most severe pathology of the hip in DDH.The reducible dislocation is characterized by the Ortolani maneuver. With the hip flexed 90 degrees, we abduct the hip and than we feel and hear the click which is the sign of the reduction of the hip. Dislocatable and subluxatable are the most common types of pathology of the hip in DDH. This deformity arises at the end of pregnancy. This is characterized by positive Barlow test, which is the provoked-dislocation test. Using it we can dislocate or subluxate the hip. It is very rare to find restricted hip movements in newborns. The limited abduction of the affected hip is the sign typical for older children, more the 3 months of age. It is crucial to repeat the clinical examination even during the same office visit. Ultrasonography has changed our diagnostic ability for DDH. These direct examinations help us in hip evaluation in the first days of the newborn period. The exact Graf classification and methodology makes possible to classify all types of hip pathology irrespective of the examiner. Another important feature of ultrasonography is the ability to monitor the treatment not only in newborn period. How to start with the prevention of DDH in newborn period? There is no any really good screening without collaboration of orthopedics surgeons and pediatricians. To achieve this, we must control our own environment, especially maternity hospitals and constantly keep pediatricians, pediatric nurses and obstetricians informed. There is no consensus in screening programs – general or limited. I personally recommend limited program. All newborns should be examined clinically after the delivery. The infants with positive or doubtful clinical signs and those with signs of high risk should be examined ultrasonographically immediately after delivery within first 2 weeks. The other children should be screened ultrasonographically at the time when most of the hips are mature enough. It is important, that if we live in the region with high percentage of late detected DDH (more than 3 months of age) the general clinical and ultasonographical screening program should be used

The purposes of this study were to review retrospectively the 25-year survival of cemented and cementless THA for hip dysplasia and to compare the effect of fixation methods on the long-term survival in patients with DDH. 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. The studied subjects were 76 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 survival at 25 years regarding any revision as the endpoint was 46% in Group-C and 76% in Group-UC. These difference was significant using Log-rank test (P=0.008). The cup survival at 25 years was 47% in Group-C and 83% in Group-UC (P= 0.0003). The stem survivals at 25 years were 95% in Group-C and 92% in Group-UC. (P= 0.416). Cementless THA in patients with DDH showed a higher survival rate at 25 years 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 25 years than cemented THA with the Bioceram in patients with OA secondary to DDH

Introduction: There is some debate about the pros and cons of selective screening of DDH in neonates as opposed to general screening. General screening puts a lot of stress on the resources available, especially in the modern day NHS, but the advocates state that this minimises the cost incurred in treating a missed DDH (by selective screening) with surgery later on. Aim: The aim of this retrospective study was to find out the effectiveness of the Southampton selective screening of babies with risk factors for DDH by finding out the number of patients presenting late with an established DDH. Materials And Methods: 6116 babies out of 26,932 live births (22.7%) in Southampton were screened between 1998 and 2003. The details of the individual outcomes and the reasons for the late presentation were obtained from the patient notes and the records of the screening program which are maintained in the clinics and by the senior author. Results: 248 new patients had Pavlik’s harness fitted for the treatment of DDH which presents a treatment rate of 0.92%. 8 patients (0.03%) presented late because they did not undergo ultrasound scanning as they did not have the risk factors as required by this selective program. 10 (0.036%) failed Pavlik’s and needed late surgery to have their DDH treated. The total operation rate was 0.066%. Discussion: The late presentation of patients in this screening program is very low and comparable to the other papers from this department and from around the world. The cost implications of treating these 8 late presenting patients was found to be a lot cheaper than carrying out a general screening program which would mean, in this case 4 times more than the cost of the present screening program

Patients with DDH are known to be at risk of early degenerative changes to their hips. To date, no consensus exists as to the most appropriate management of this group, with many surgical options being associated with specific complications such as dislocation and early wear. In addition, modern resurfacing methods are considered by many to be contra-indicated in patients with DDH due to the technical difficulty of the procedure. This prospective study analyses a single surgeon series of known DDH hips that underwent metal on metal resurfacing from November 1999 to July 2004 inclusive. There were 31 resurfacings carried out on 28 patients (11 males, 17 females). The mean age of the study group at the time of surgery was 43.9+/−9.1 years. No patient was lost to follow up. Pre-operatively, 23 hips were classified as Crowe I (n=9), II (n=5), III (n=5) and IV (n=4). Patients were followed up to a mean of 46.4+/−18.1 months. The mean Harris Hip scores were 54.9+/−9.3 pre-operatively and 98.1+/−4.9 post-operatively (p< 0.001, Student’s t-test). Using the UCLA activity profile, the mean scores were 3.2+/−1.0 pre-operatively and 6.4+/−1.8 post-operatively (p< 0.001, Student’s t-test). Although the management of young patients with early degenerative changes secondary to DDH remains controversial, the results of this study suggest that not only is resurfacing technically possible even in advanced cases, it also offers excellent functional outcomes and should be considered in appropriate cases

Aims. Brace treatment is the cornerstone of managing developmental dysplasia of the hip (DDH), yet there is a lack of evidence-based treatment protocols, which results in wide variations in practice. To resolve this, we have developed a comprehensive nonoperative treatment protocol conforming to published consensus principles, with well-defined a priori criteria for inclusion and successful treatment. Methods. This was a single-centre, prospective, longitudinal cohort study of a consecutive series of infants with ultrasound-confirmed DDH who underwent a comprehensive nonoperative brace management protocol in a unified multidisciplinary clinic between January 2012 and December 2016 with five-year follow-up radiographs. The radiological outcomes were acetabular index-lateral edge (AI-L), acetabular index-sourcil (AI-S), centre-edge angle (CEA), acetabular depth ratio (ADR), International Hip Dysplasia Institute (IHDI) grade, and evidence of avascular necrosis (AVN). At five years, each hip was classified as normal (< 1 SD), borderline dysplastic (1 to 2 SDs), or dysplastic (> 2 SDs) based on validated radiological norm-referenced values. Results. Of 993 infants assessed clinically and sonographically, 21% (212 infants, 354 abnormal hips) had DDH and were included. Of these, 95% (202 infants, 335 hips) successfully completed bracing, and 5% (ten infants, 19 hips) failed bracing due to irreducible hip(s). The success rate of bracing for unilateral dislocations was 88% (45/51 infants) and for bilateral dislocations 83% (20/24 infants). The femoral nerve palsy rate was 1% (2/212 infants). At five-year follow-up (mean 63 months (SD 5.9; 49 to 83)) the prevalence of residual dysplasia after successful brace treatment was 1.6% (5/312 hips). All hips were IHDI grade I and none had AVN. Four children (4/186; 2%) subsequently underwent surgery for residual dysplasia. Conclusion. Our comprehensive protocol for nonoperative treatment of infant DDH has shown high rates of success and extremely low rates of residual dysplasia at a mean age of five years. Cite this article: Bone Joint J 2023;105-B(8):935–942

DDH incidence falls from 5–20 per 1000 at birth to 1–2 per 1000 by 3 weeks. Some patients present late and frequently require surgical intervention. If the hip cannot be contained without tension, these children undergo open reduction +/− a femoral shortening, varus and derotation osteotomy. Salter’s osteotomy, may be performed either at index surgery or later in the presence of persisting acetabular dysplasia. Our aim was to see if we could predict which cases of persistent DDH would require both femoral and pelvic surgery to contain the affected hip, using a single plain AP radiograph of the pelvis in the outpatient setting. We performed a retrospective study of all children older than 18 months with persistent DDH of one or both hips, over the last 5 years, who had undergone femoral and/or pelvic surgery to contain the hip. Plain AP pelvic radiographs were standardised according to the method described by Tonnis. From these radiographs the acetabular indices and child’s age in months, were recorded. Syndromic and children with non-standard x-rays were excluded. Thirty nine hips (34 female, 5 male), age range of 18–102 months, formed our study group. 53% of hips having femoral surgery later required pelvic surgery for persisting acetabular dysplasia. Examining the data in these cases, the difference between the acetabular index of the normal and affected hip was always greater than 20 degrees and the child’s age in months. Using this method we conclude that it is possible to predict which cases of persistent DDH will require pelvic surgery to fully contain the affected hip and that this can be done with one AP pelvic radiograph in the outpatient clinic. The benefit is avoidance of unnecessary pelvic osteotomies, and being able to determine the cases which should have a pelvic osteotomy at index procedure

Introduction: To measure the incidence of late presenting DDH following the introduction of selective ultrasound screening of neonatal hips with associated risk factors. Method: Retrospective cohort study of children with late diagnosed DDH in a defined population of Greater Glasgow Region. A hip ultrasound program was introduced in the year 1997 for secondary screening of children with risk factors for DDH. The departmental and theatre database was used to identify children with late diagnosed DDH. (Defined as diagnosed 3 months after birth) Demographic details, age at presentation, presence of risk factors (Breech presentation, family history, clicks, caesarian section) and details of treatment were recorded. The number of live births for each year was obtained from the General Registrar Office for Scotland. The incidence of late presenting DDH was calculated taking in to account the year of child’s birth. The incidence of late DDH was then compared between the period 1992 –1996 and 1997– 2001. Results: 78 children were identified, of which 49 babies were between 1992 – 96 and 29 between 1997 –01. The average age at diagnosis was 17 months (Median 15 months, range 5 –84 months). The average annual incidence from 1992 –6 was 0.84 per 1000 live births and from 1997 – 2001 was 0.57 per 1000 live births. This decrease in incidence of late DDH was not significant at 5% level (chi squared p = 0.088). 64 children (82%) with late diagnosed DDH had no factors that could be perceived as risk factors for the condition. Discussion: Targeted ultrasound screening of babies with risk factors appears to have reduced the average incidence of late DDH from 0.84 to 0.57 per 1000 live births. However this reduction in incidence is not statistically significant. The vast majority of late presenters (82%) do not have risk factors. It remains unclear whether universal ultrasound screening program, practiced in some parts of United Kingdom is a cost effective alternative to eliminate the incidence of late presenting DDH

Aims: The purpose of this study is the evaluation of the ultrasound screening process for DDH in a population of neonates from the prefecture of Chania, in Western Crete, an area with a history of excessively high incidence of DDH. Methods: Within the period between 1/7/99 and 1/7/01 (24 months) 1247 neonates (2494 hips) were examined clinically and ultrasonograþcally (transverse, oblique, dynamique views), all babies whose parents both descend from this area for generations. They were referred by a paediatrician for one or more of the following reasons: limited hip abduction (48%), hip laxity (6%), positive family DDH history (27%), musculoskeletal congenital abnormalities (11%), breech delivery (5.1%), paediatricianñs or parentsñ insecurity (18%).Results: We had the following þndings: signiþcant dysplasia-Graf III in 3.7%, milder dysplasia Ð Graf IIc, d in 7.2%, immature but satisfactory hips Ð Graf IIa, b in 19.3% and normal hips in 69.5% of the hips. Double diapers (sheets) were used in 43%, Frejka in 3% and Pavlik harness in 4.2% of the cases. In two cases the dysplasia persisted and we had to use a spica cast. Satisfactory results have been observed in all but one case. X-ray control was necessary in six children. Conclusion: Hip ultrasound, in experienced hands, is a safe, quick, well tolerated, non-inventory method for DDH screening, treatment and follow-up in neonates Ð babies in their þrst year of life

Normal acetabular development in developmental dysplasia of the hip (DDH) depends upon early and maintained congruent reduction. Computed tomography is an accepted method for evaluating this and attempts to quantify hip reduction, by various angular and linear measurements, have been reported. The aim of this study was to assess initial CT scans, following open reduction in the older child with DDH, with comparison of outcome to evaluate prognostic value. Method: Thirty consecutive patients underwent open reduction for DDH, with a mean age of 25.9 months at the time of operation. Acetabular morphology and the position of the femoral head were evaluated on the initial CT scan, taken on the first postoperative day, and AP pelvic radiograph taken at the latest follow-up. Results: The acetabulae of the dislocated hips were found to be significantly more anteverted than the normal. The dislocated hips also had significantly increased lateral displacement both initially and at latest follow-up. Posterior displacement of the proximal femoral metaphysis should raise concern due to an association with the need for further surgical intervention. These results did not however correlate with outcome. In conclusion, despite the significant differences noted between DDH and normal hips they did not predict acetabular development or persistent acetabular dysplasia

Purpose of Study. To evaluate the results of using external fixation to stabilise femoral derotation osteotomy involved in DDH surgery. Methods and results. A retrospective analysis was performed on 44 patients undergoing 48 femoral osteotomies for DDH surgery between the years 2001 and 2009 by a single surgeon (senior author MC). The external fixator was used either during the primary procedure involving femoral shortening to aid in hip reduction (4 patients) or to correct femoral malrotation in a reduced hip as a secondary procedure(40 patients). As the external fixator frame was within the hip spica it was not a cause of concern to the parents or the child. There was no evidence of any pin tract infection and all patients eventually progressed to satisfactory bony union. One patient had delayed union which was treated successfully with conservative management and one patient had a malunion requiring a further osteotomy and extended treatment with the external fixator. Conclusion. External fixation is a viable alternative for the traditional internal fixation used for femoral osteotomy involving DDH Surgery. Our study has shown that it produces satisfactory results with minimal complications. Apart from minimising tissue scarring in the muscle and subcutaneous planes, it gives a cosmetically better scar. If there is further need for revision surgery it provides healthy tissue planes for dissection. Furthermore it eliminates the need for additional surgery required for removal of plates

The aim of this research was to elaborate indications for application of some methods of surgical treatment of DDH in teenagers. There are some significant problems with surgical treatment of DDH in teenagers. The most serious one is that the results of routine reconstructive methods usually satisfy neither the patients nor the orthopaedists. In addition, in most of the cases it is too early for total hip arthroplasty. From 1985 to 1996, we operated twenty teenagers with late stages of DDH. Group A was eight patients (12 to 14 years old) with marginal hip luxation (acetabulum angle was more than 40°). Group B was seven patients (10 to12 years old) with iliac hip dislocation (acetabulum angle was more than 50°) and Group C was five patients (11 to 14 years old) with iliac hip dislocation (plane acetabulum). In Group A we performed our first two-stage method of surgical treatment. For the first stage we performed corrective transtrochanteric femur osteotomy (AO plate fixation) and partial acetabuloplasty, and corrected not more than half of the acetabulum angle deficiency. The second stage was performed four to six months later. We removed the femur AO plate and again performed a partial acetabuloplasty. A spherical acetabulum with normal angle and stable hip joint were the results of this method. In Group B we performed our second two-stage method of surgical treatment. For the first stage we performed a corrective and shortening (2 to 3 cm) transtrochanteric femur osteotomy (AO plate fixation), open reduction of the hip and partial acetabuloplasty and corrected not more than half of acetabulum angle deficiency. The second stage was performed 4 to 6 months later and we removed the femur AO plate and performed a Salter osteotomy. A spherical acetabulum with normal angle and a stable hip joint were also the results of the application of this method. In Group C we performed the well-known Ilizarov technique of femur reconstruction (modification of Schanz osteotomy with correction of femur shortening). Normalisation of gait and reduction of the Trendelenburg sign were the results of the application of this method. The results of these methods were studied 3 to 10 years after the end of postoperative rehabilitation. Good results were obtained in 16 cases, satisfactory in four (one in Group A, two in Group B and one in Group C)

Aims. To assess if congenital foot deformity is a risk factor for developmental dysplasia of the hip (DDH). Methods. Between 1996 and 2012, 60,844 children were born in Sør-Trøndelag county in Norway. In this cohort study, children with risk factors for DDH were examined using ultrasound. The risk factors evaluated were clinical hip instability, breech delivery, a family history of DDH, a foot deformity, and some syndromes. As the aim of the study was to examine the risk for DDH and foot deformity in the general population, children with syndromes were excluded. The information has been prospectively registered and retrospectively analyzed. Results. Overall, 494 children (0.8%) had DDH, and 1,132 (1.9%) a foot deformity. Of the children with a foot deformity, 49 (4.3%) also demonstrated DDH. There was a statistically significant increased association between DDH and foot deformity (p < 0.001). The risk of DDH was highest for talipes calcaneovalgus (6.1%) and club foot (3.5%), whereas metatarsus adductus (1.5%) had a marginal increased risk of DDH. Conclusion. Compared with the general population, children with a congenital foot deformity had a significantly increased risk for DDH and therefore we regard foot deformity as a true risk factor for DDH. Cite this article: Bone Joint J 2020;102-B(11):1582–1586

Aim: To assess the effectiveness and need for X-rays undertaken at 9 to 12 months of age in cases were children have a strong family history of DDH and have had a normal ultra-sound scan at 6 weeks of age. Materials and Methods: A retrospective study was undertaken over a five-year period. 122 children were identified as having a positive family history of DDH with a normal ultra-sound scan at 6 weeks. 56% were female and 44% were male. 6 were breech (4.9%). The mean ultra-sound was undertaken at 8.9 weeks. The mean X-ray was undertaken at 11.6 months. Acetabular dysplasia was diagnosed if the acetabular index was over 30 degrees. All X-rays were reviewed by one specialist. Results: 3 children were noted to have late acetabular dysplasia (2.5%). One case was bilateral and 2 cases were unilateral. Conclusion: The study showed a sub-group of cases where there was an incidence of acetabular dysplasia where the ultra-sound was normal at 6 weeks in those with a strong family history of DDH. It was felt that the finding of this dysplasia supports the policy to X-ray these cases at one year because of the significantly increased risk of acetabular dysplasia in this group

Introduction. Neck and cup impingement resulted in producing larger amount of wear and risk for dislocation after total hip arthroplasty. DDH had more complex to adjust combined cup and femoral neck anteversion during surgery. Dislocation is the second most prevalent complication in total hip replacement with a 2–4% incidence. These resulted in significant financial burden to health care system. Sixteen million US dollars or more cost had in Japanese health insurance system every year. Purpose of this study was to evaluate neck-cup impingement with neck changeable M/L taper Kinectiv stem for DDH patients. Materials & Methods. Single surgeon's series were analyzed neck cup impingement of 1152 primary total hip surgeries with DDH. 269 hips in men, surgical approach were 754 mini-one antero-lateral, 284 mini- Watson-Jones, and 114 Hardinge. Acetabular cups were seated 20 degrees anteversion. Kinectiv Stem (Zimmer, Warsaw, IN) was inserted manually with standard technique. Femoral head selection was performed 26mm CoCr basis. 32mm were used for 75 years old or more, and 36mm were 80 years or older. First trial was performed with straight type of neck and 26mm femoral head based on preoperative templating. At neck and head trial to evaluated antero-superior impingement with “flex+add.+IR” and postero-inferior impingement with “ext.+add.+ER”. If the neck and cup impingement occurred even if no dislocation, necks were replaced counter version or larger offset. Results. Neck trial was 2 to 3 times during surgery (ave. 1.9). Version was changed 395(33%) cases. Surgeon selected larger offset in 246, 235 longer length, 99 shorter length. Larger offset with longer length were used in 229 (20%), 117 (10%) had larger offsets and shorter length compared to 2D templating before surgery. We had 2 dislocations (0.48%) with10 degree extended lip PE (2/359: 0.56%) and 2 for flat PE liner (2/793: 0.25%) fixed with manual reduction. All were using very short neck (E; minus 4 in length and S; minus 4 in length, plus 4 in offset) with smaller arc of movement type because of tight to redact compared expected proper positions. All dislocated cases were revised with larger femoral head. Our first series of 1500 Versys system with 10 degree extended lips had 0.74% (14/1880) (2004–9) dislocation rate. Kinectiv neck changeable stem had 66% reduction of dislocation rate (p<0.05). Averaged hospital stay was 7 (3–12) days. Discussion. One Kinectiv stem had 60 variety of necks based on 4 mm head center difference. Large amount of variation especially anteverted or retroverted neck selection might reduce neck-cup impingement compared to other straight type of femoral stems. Combined anteversion is very important especially in DDH patients, because of larger femoral anteversion. Proper offset and leg length are also very important issues for any type of patients. This type of stem had more advantages than straight type monolithic stems to reduce wear and dislocation caused by impingement. Care must be taken for reducing impingement with selecting shorter length or offset during surgery. Lower dislocation rate are very effective to health insurance system