Introduction: Osteonecrosis of the femoral head with joint space narrowing in young patients aged less than fifty years old was treated with posterior rotational osteotomy. Changes of the acetabular roof were observed after operation. Early remodeling of the acetabular roof after operation was studied radiographically. Materials and Methods: Eighteen hips in 15 patients treated by posterior rotational osteotomy were subjects for this study. The age of the patients ranged from 15 to 50 (mean of 36 years). Eleven patients were women, 4 were men. The etiologic factors were steroid administration in 9 patients, alcoholic abuse in 1 patient, trauma in 7 patients, and no apparent factor in 1 patient. Changes of the acetabular roof on antero-posterior radiographs were observed at 6 months, 1 year, and 2 years postoperatively. Atrophic change and uniform shape of the acetabular roof was studied in each period. Results: At 6 months after operation, atrophic change was noted on all 18 hips. None of uniform shape was found. Atrophic change of 10 hips (56%) was found 1 year postoperatively. Shape of acetabular roof was improved and uniformed in 8 hips. In all 18 hips 2 years after operation, shape of acetabular roof was remodeled and uniformed. Discussion: From these results, we thought acetabular roof of femoral head involving necrosis with joint narrowing was remodeled at an early period postoperatively

To propose a modified approach to measuring femoro-epiphyseal acetabular roof (FEAR) index while still abiding by its definition and biomechanical basis, and to compare the reliabilities of the two methods. To propose a classification for medial sourcil edges. We retrospectively reviewed a consecutive series of patients treated with periacetabular osteotomy and/or hip arthroscopy. A modified FEAR index was defined. Lateral center-edge angle, Sharp's angle, Tonnis angle on all hips, as well as FEAR index with original and modified approaches were measured. Intra- and inter-observer reliability were calculated as intraclass correlation coefficients (ICC) for FEAR index with both approaches and other alignments. A classification was proposed to categorize medial sourcil edges. ICC for the two approaches across different sourcil groups were also calculated. After reviewing 411 patients, 49 were finally included. Thirty-two patients (40 hips) were identified as having borderline dysplasia defined by an LCEA of 18 to 25 degrees. Intra-observer ICC for the modified method were good to excellent for borderline hips; poor to excellent for DDH; moderate to excellent for normal hips. As for inter-observer reliability, modified approach outperformed original approach with moderate to good inter-observer reliability (DDH group, ICC=0.636; borderline dysplasia group, ICC=0.813; normal hip group, ICC=0.704). The medial sourcils were classified to 3 groups upon its morphology. Type II(39.0%) and III(43.9%) sourcils were the dominant patterns. The sourcil classification had substantial intra-observer agreement (observer 4, kappa=0.68; observer 1, kappa=0.799) and moderate inter-observer agreement (kappa=0.465). Modified approach to FEAR index possessed greater inter-observer reliability in all medial sourcil patterns. The modified FEAR index has better intra- and inter-observer reliability compared with the original approach. Type II and III sourcils accounts for the majority to which only the modified approach is applicable

Aims. A borderline dysplastic hip can behave as either stable or unstable and this makes surgical decision making challenging. While an unstable hip may be best treated by acetabular reorientation, stable hips can be treated arthroscopically. Several imaging parameters can help to identify the appropriate treatment, including the Femoro-Epiphyseal Acetabular Roof (FEAR) index, measured on plain radiographs. The aim of this study was to assess the reliability and the sensitivity of FEAR index on MRI compared with its radiological measurement. Patients and Methods. The technique of measuring the FEAR index on MRI was defined and its reliability validated. A retrospective study assessed three groups of 20 patients: an unstable group of ‘borderline dysplastic hips’ with lateral centre edge angle (LCEA) less than 25° treated successfully by periacetabular osteotomy; a stable group of ‘borderline dysplastic hips’ with LCEA less than 25° treated successfully by impingement surgery; and an asymptomatic control group with LCEA between 25° and 35°. The following measurements were performed on both standardized radiographs and on MRI: LCEA, acetabular index, femoral anteversion, and FEAR index. Results. The FEAR index showed excellent intraobserver and interobserver reliability on both MRI and radiographs. The FEAR index was more reliable on radiographs than on MRI. The FEAR index on MRI was lower in the stable borderline group (mean -4.2° (. sd. 9.1°)) compared with the unstable borderline group (mean 7.9° (. sd. 6.8°)). With a FEAR index cut-off value of 2°, 90% of patients were correctly identified as stable or unstable using the radiological FEAR index, compared with 82.5% using the FEAR index on MRI. The FEAR index was a better predictor of instability on plain radiographs than on MRI. Conclusion. The FEAR index measured on MRI is less reliable and less sensitive than the FEAR index measured on radiographs. The cut-off value of 2° for radiological FEAR index predicted hip stability with 90% probability. Cite this article: Bone Joint J 2019;101-B:1578–1584

Aims: A main condition in succesfull rearthroplasty of acetabular component is the way of stabilizing this component in physiological site, with a full support on bone. Segmental and cavitary acetabular defect are often caused by aseptic loosening of the implants. The use of bulky corticocancellous grafts, which would be loaded is recommended. Methods: Acetabular roof reconstruction technique for revision cemented THA, according to Zuk is presented in a series 42 patients (19 male and 23 female aged 56– 68 yr). No screws and bone pins were used for cortico-cancellous graft þxation. Results: In 22 patients autogenic graft was sufþciently remodeled within 12 months, in 16 cases with frozen allogenic graft it lasted 20 months on average. Longer remodeling time depended on the size of acetabular defect, coexisting conditions and postoperative complication. In 2 cases an autolysis of the graft occurred; one patient underwent prolonged corticosteroid therapy before; the other one was exposed extensively to chemical substances prior to surgery. Aseptic loosening of the acetabular roof in this cases followed. Conclusions: Reconstruction of acetabular roof defect in this method is relatively simple and can diminish complication rate bounded with potential electrolysis harmfull effect. A mean remodeling time of reconstructed acetabular bone roof with this method was equal as with stabilized graft (pins and screws)

The definition of osseous instability in radiographic borderline dysplastic hips is difficult. A reliable radiographic tool that aids decision-making specifically, a tool that might be associated with instability-therefore would be very helpful for this group of patients. The aims of this study were:. (1) To compare a new radiographic measurement, which we call the Femoro-Epiphyseal Acetabular Roof (FEAR) index, with the lateral centre-edge angle (LCEA) and acetabular index (AI), with respect to intra- and interobserver reliability; (2) to correlate AI, neck-shaft angle, LCEA, iliocapsularis volume, femoral antetorsion, and FEAR index with the surgical treatment received instable and unstable borderline dysplastic hips; and (3) to assess whether the FEAR index is associated clinical instability in borderline dysplastic hips. We defined and validated the FEAR index in 10 standardized radiographs of asymptomatic controls using two blinded independent observers. Interrater and intrarater coefficients were calculated, supplemented by Bland-Altman plots. We compared its reliability with LCEA and AI. We performed a case-control study using standardized radiographs of 39 surgically treated symptomatic borderline radiographically dysplastic hips and 20 age-matched controls with asymptomatic hips (a 2:1 ratio), the latter were patients attending our institution for trauma unrelated to their hips but who had standardized pelvic radiographs between January 1, 2016 and March 1, 2016. Patient demographics were assessed using univariate Wilcoxon two-sample tests. There was no difference in mean age (overall: 31.5 ± 11.8 years [95% CI, 27.7–35.4 years]; stable borderline group: mean, 32.1± 13.3 years [95%CI, 25.5–38.7 years]; unstable borderline group: mean, 31.1 ± 10.7 years [95% CI, 26.2–35.9 years]; p = 0.96) among study groups. Treatment received was either a periacetabular osteotomy (if the hip was unstable) or, for patients with femoroacetabular impingement, either an open or arthroscopic femoroacetabular impingement procedure. The association of received treatment categories with the variables AI, neck-shaft angle, LCEA, iliocapsularis volume, femoral antetorsion, and FEAR index were evaluated first using Wilcoxon two-sample tests (two-sided) followed by stepwise multiple logistic regression analysis to identify the potential associated variables in a combined setting. Sensitivity, specificity, and receiver operator curves were calculated. The primary endpoint was the association between the FEAR index and instability, which we defined as migration of the femoral head either already visible on conventional radiographs or recentering of the head on AP abduction views, a break of Shenton's line, or the appearance of a crescent-shaped accumulation of gadolinium in the posteroinferior joint space at MR arthrography. The FEAR index showed excellent intra- and interobserver reliability, superior to the AI and LCEA. The FEAR index was lower in the stable borderline group (mean, −2.1 ± 8.4; 95% CI, −6.3 to 2.0) compared with the unstable borderline group (mean, 13.3 ± 15.2; 95% CI, 6.2–20.4) (p < 0.001) and had the highest association with treatment received. A FEAR index less than 5° had a 79% probability of correctly assigning hips as stable and unstable, respectively (sensitivity 78%; specificity 80%). A painful hip with a LCEA of 25° or less and FEAR index less than 5° is likely to be stable, and in such a situation, the diagnostic focus might more productively be directed toward femoroacetabular impingement

We wanted to evaluate the clinical and radiological results of acetabular revision using the acetabular reinforcement ring and allograft impaction in patients with severe acetabular bony defect.

41 hips revision arthroplasty using reinforcement ring were performed between April 1997 and October 2005 and were followed up for more than two years. The cause of primary arthroplasty was AVN in 18 cases, secondary osteoarthritis (OA) in 17 cases, fracture in cases and primary OA in 1 case. The cause of revision arthroplasty was acetabular cup loosening in 20 cases, massive osteolysis in 14 cases, infection in 4 cases, liner dissociation in 2 cases, and recurrent dislocation in 1 case. The average period between primary and revision arthroplasty was 11.4 years (range 0.6 to 29.1 years). Acetabular defects were classified based on the AAOS classification and Paprosky classification system. All were treated with autografts or allografts. Muller ring was used in 18 cases, Burch-Schneider ring was used in 14 cases, and Ganz ring in 9 cases. Clinical evaluations were performed according to the Harris hip score (HHS), and the radiographic results were evaluated by progression of acetabular component loosening, union of bone grafts, periacetabular osteolysis, and migration of the hip center.

The mean preoperative Harris hip score of 64.9 was improved to 91.8 points at the latest follow-up. There were 39 cases of type 3 defect, 2 cases of type 4 defect according to the AAOS classification and 8 cases of type 2B defect, 3 cases of type 2C defect, 28 cases of type 3A defect, and 2 cases of type 3B defect according to Paprosky classification.

Radiographically, the bone grafts were well united except one case. The mean preoperative hip center of rotation which was vertically 32.3mm, horizontally 33.2 mm migrated to vertically 26 mm, horizontally 33.2 mm postoperatively and it was statistically significant.

The mean preoperative abductor lever arm of 41.7 mm changed to 45 mm postoperatively which was statistically insignificant. However the mean preoperatiave body lever arm of 89.4 mm changed to 96.9 mm postoperatively which was statistically significant. Postoperative complications were cup loosening in 1 case, dislocation in 2 cases, and recurrence of deep infection in 1 case.

Clinically and radiographically, acetabular reconstruction using reinforcement ring showed very promising short term result. We conclude that reinforcement ring can provide stable support for grafted bone in severe bone defect. But meticulous surgical technique to get initial firm stability of ring and optimal indication in mandactory for the successful result.

Aims. The objective of this study was to present the outcomes of rotational acetabular osteotomy (RAO) over a 30-year period for osteoarthritis (OA) secondary to dysplasia of the hip in pre- or early-stage OA. Methods. Between September 1987 and December 1994, we provided treatment to 47 patients (55 hips) with RAO for the management of pre- or early-stage OA due to developmental hip dysplasia. Of those, eight patients (11 hips) with pre-OA (follow-up rate 79%) and 27 patients (32 hips) with early-stage OA (follow-up rate 78%), totalling 35 patients (43 hips) (follow-up rate 78%), were available at a minimum of 28 years after surgery. Results. In the pre-OA group, the mean Merle d'Aubigné score improved significantly from 14.5 points (SD 0.7) preoperatively to 17.4 points at final follow-up (SD 1.2; p = 0.004) and in the early-stage group, the mean score did not improve significantly from 14.0 (SD 0.3) to 14.6 (SD 2.4; p = 0.280). Radiologically, the centre-edge angle, acetabular roof angle, and head lateralization index were significantly improved postoperatively in both groups. Radiological progression of OA was observed in two patients (two hips) in the pre-OA group and 17 patients (18 hips) in the early-stage group. Kaplan-Meier survival analysis, with radiological progression of OA as the primary outcome, projected a 30-year survival rate of 81.8% (95% confidence interval (CI) 0.59 to 1.00) for the pre-OA group and 42.2% (95% CI 0.244 to 0.600) for the early-stage group. In all cases, the overall survival rate stood at 51.5% (95% CI 0.365 to 0.674) over a 30-year period, and when the endpoint was conversion to total hip arthroplasty, the survival rate was 74.0% (95% CI 0.608 to 0.873). Conclusion. For younger patients with pre-OA, joint preservation of over 30 years can be expected after RAO. Cite this article: Bone Joint J 2024;106-B(5 Supple B):25–31

Aims. The aims of this study were to compare clinically relevant measurements of hip dysplasia on radiographs taken in the supine and standing position, and to compare Hip2Norm software and Picture Archiving and Communication System (PACS)-derived digital radiological measurements. Methods. Preoperative supine and standing radiographs of 36 consecutive patients (43 hips) who underwent periacetabular osteotomy surgery were retrospectively analyzed from a single-centre, two-surgeon cohort. Anterior coverage (AC), posterior coverage (PC), lateral centre-edge angle (LCEA), acetabular inclination (AI), sharp angle (SA), pelvic tilt (PT), retroversion index (RI), femoroepiphyseal acetabular roof (FEAR) index, femoroepiphyseal horizontal angle (FEHA), leg length discrepancy (LLD), and pelvic obliquity (PO) were analyzed using both Hip2Norm software and PACS-derived measurements where applicable. Results. Analysis of supine and standing radiographs resulted in significant variation for measurements of PT (p < 0.001) and AC (p = 0.005). The variation in PT correlated with the variation in AC in a limited number of patients (R. 2. = 0.378; p = 0.012). Conclusion. The significant variation in PT and AC between supine and standing radiographs suggests that it may benefit surgeons to have both radiographs when planning surgical correction of hip dysplasia. We also recommend using PACS-derived measurements of AI and SA due to the poor interobserver error on Hip2Norm. Cite this article: Bone Joint J 2021;103-B(11):1662–1668

Aims

The aim of this study was to investigate the agreement in interpretation of the quality of the paediatric hip ultrasound examination, the reliability of geometric and morphological assessment, and the relationship between these measurements.

Satisfactory intermediate and long-term results of rotational acetabular osteotomy (RAO) for the treatment of early osteoarthritis secondary to developmental dysplasia of the hip have been reported. The purpose of this study is to examine the 30-year results of RAO. Between 1987 and 1994, we treated 49 patients (55 hips) with RAO for diagnosis of pre- OA or early-stage OA. Of those patients, 35 patients (43 hips) were available at a minimum of 28 years. The follow-up rate was 78.2% and the mean follow-up was 30.5 years. The mean age at the time of surgery was 34 years. Clinical evaluation was performed with the Merle d'Aubigne and Postel rating scale, and radiographic analyses included measurements of the center-edge angle, acetabular roof angle, and head lateralization index on preoperative, postoperative AP radiographs of the pelvis. Postoperative joint congruency was classified into four grades. The radiographic evidence of progression of OA was defined as the minimum joint space less than 2.5mm. The mean preoperative clinical score was 14.0, which improved to a mean of 15.3 at the time of the latest follow-up. The mean center-edge angle improved from 0.6° preoperatively to 34° postoperatively, the mean acetabular roof angle improved from 28.4°preoperatively to 1.0°postoperatively, the mean head lateralization index improved from 0.642 preoperatively to 0.59 postoperatively. Postoperative joint congruency was excellent in 11 hips, good in 29 hips, and fair in 3 hips. Nineteen patients (20 hips) had radiographic OA progression, and 10 patients (11 hips) were converted to THA. Kaplan-Meier survivorship analysis, with radiographic OA progression as the end point, predicted survival of 75.6% at 20 years and 48.8% at 30 years, and with THA conversion as the end point, 90.2% at 20 years and 71.2% at 30 years. The RAO is an effective surgical procedure for symptomatic dysplastic hips of pre- and early-stage OA and could change the natural history of the dysplastic hip

Aims. This study reports mid-term outcomes after periacetabular osteotomy (PAO) exclusively in a borderline hip dysplasia (BHD) population to provide a contrast to published outcomes for arthroscopic surgery of the hip in BHD. Methods. We identified 42 hips in 40 patients treated between January 2009 and January 2016 with BHD defined as a lateral centre-edge angle (LCEA) of ≥ 18° but < 25°. A minimum five-year follow-up was available. Patient-reported outcomes (PROMs) including Tegner score, subjective hip value (SHV), modified Harris Hip Score (mHHS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) were assessed. The following morphological parameters were evaluated: LCEA, acetabular index (AI), α angle, Tönnis staging, acetabular retroversion, femoral version, femoroepiphyseal acetabular roof index (FEAR), iliocapsularis to rectus femoris ratio (IC/RF), and labral and ligamentum teres (LT) pathology. Results. The mean follow-up was 96 months (67 to 139). The SHV, mHHS, WOMAC, and Tegner scores significantly improved (p < 0.001) at last follow-up. According to SHV and mHHS, there were three hips (7%) with poor results (SHV < 70), three (7%) with a fair score (70 to 79), eight (19%) with good results (80 to 89), and 28 (67%) who scored excellent (> 90) at the last follow-up. There were 11 subsequent operations: nine implant removals due to local irritation, one resection of postoperative heterotopic ossification, and one hip arthroscopy for intra-articular adhesions. No hips were converted to total hip arthroplasty at last follow-up. The presence of preoperative labral lesions or LT lesions did not influence any PROMs at last follow-up. From the three hips that had poor PROMs, two have developed severe osteoarthritis (> Tönnis II), presumably due to surgical overcorrection (postoperative AI < -10°). Conclusion. PAO is reliable in treating BHD with favourable mid-term outcomes. Concomitant LT and labral lesions did not negatively influence outcomes in our cohort. Technical accuracy with avoidance of overcorrection is essential in achieving successful outcomes. Cite this article: Bone Joint J 2023;105-B(7):735–742

Aims. The aim of this study was to report the long-term results of rotational acetabular osteotomy (RAO) for symptomatic hip dysplasia in patients aged younger than 21 years at the time of surgery. Patients and Methods. We evaluated 31 patients (37 hips) aged younger than 21 years at the time of surgery retrospectively. There were 29 female and two male patients. Their mean age at the time of surgery was 17.4 years (12 to 21). The mean follow-up was 17.9 years (7 to 30). The RAO was combined with a varus or valgus femoral osteotomy or a greater trochanteric displacement in eight hips, as instability or congruence of the hip could not be corrected adequately using RAO alone. Results. The mean Merle d’Aubigné clinical score improved significantly from 15.4 to 17.2 (p < 0.0001). The mean centre-edge (CE) angle improved from -2.6° to 26°, the mean acetabular roof angle improved from 3.0° to 5.2°, and the mean head lateralization index improved from 0.68 to 0.62. Progression of radiological osteoarthritis (OA) was seen in seven hips, but no patient underwent total hip arthroplasty. Conclusion. RAO is an effective form of correction for a severely dysplastic hip in adolescent and young adult patients. Cite this article: Bone Joint J 2019;101-B:390–395

Introduction: Operative treatment of secondary osteoarthritis due to congenital hip disease (CHD) in adults presents a challenging issue. Various classifications have been proposed for congenital hip disease in search for the best treatment option. Aim of this prospective study is to find measurements important in preoperative planning and their correlation with postoperative results. Materials and Methods: We have included 64 patients (70 hips) with CHD consecutively scheduled for operation. Preoperatively congenital hip disease was classified according to Crowe, Hartofilakidis and Eftekhar and center of rotation was determined using Ranawat’s method. Distance between ideal and actual center rotation was measured. Further, distance between medial acetabular wall and medial pelvic rim (medial bone bulk) in the line of ideal center of rotation was measured. Another measurement was distance between ideal acetabular roof point and medial pelvic rim. On the postoperative radiographs centre of the femoral head was recorded. Correlation between Crowe, Hartofilakidis and Eftekhar classifications with distance between ideal and postoperative center rotation and medial bone bulk were calculated using Pearson correlation. Correlation was also analyzed using information about distance between ideal acetabular roof point and medial pelvic rim. Results: Data analysis showed that there is the strongest connection between degree of CHD determined using Eftaker classification and distance between ideal and actual rotation center (r=0.417, p=0.011). Crowe and Hartofilakidis classifications also shows statistically significant connection, however not that strong (r= 0.384, p=0.021 for Crowe and r=0.373, p=0.025 for Hartofilakidis). Eftaker classification shows the strongest correlation with medial bone bulk r=0.425, a p=0.010. Similar is Crowe classification (r=0.341, p=0.042), while there is no statistically significant correlation with Hartofilakidis classification. Results also shows that when there is higher degree of congenital hip disease there is thinner bone bulk in line of ideal acetabular roof (for Crowe r= −0.360, p=0.031, for Hartofilakidis r= −0.354, p=0.34). Conclusion: Results show that severity of dysplasia according to Crowe, Hartofilakidis and Eftekhar correlates with postoperative position of rotation center. Eftekhar classification gives the best insight to how much medial bone bulk is available. For bone bulk on the acetabular roof predictions can be made using both Crowe and Hartofilakidis system. However, one classification still does not provide with all information we found important for correct endoprothesis placement in relation to center of rotation especially about acetabular depth, and bone mass on the medial acetabular wall and acetabular roof

Aims. Rotational acetabular osteotomy (RAO) is an effective joint-preserving surgical treatment for acetabular dysplasia. The purpose of this study was to investigate changes in muscle strength, gait speed, and clinical outcome in the operated hip after RAO over a one-year period using a standard protocol for rehabilitation. Patients and Methods. A total of 57 patients underwent RAO for acetabular dysplasia. Changes in muscle strength of the operated hip, 10 m gait speed, Japanese Orthopaedic Association (JOA) hip score, and factors correlated with hip muscle strength after RAO were retrospectively analyzed. Results. Three months postoperatively, the strength of the operated hip in flexion and abduction and gait speed had decreased from their preoperative levels. After six months, the strength of flexion and abduction had recovered to their preoperative level, as had gait speed. At one-year follow-up, significant improvements were seen in the strength of hip abduction and gait speed, but muscle strength in hip flexion remained at the preoperative level. The mean JOA score for hip function was 91.4 (51 to 100)) at one-year follow-up. Body mass index (BMI) showed a negative correlation with both strength of hip flexion (r = -0.4203) and abduction (r = -0.4589) one year after RAO. Although weak negative correlations were detected between strength of hip flexion one year after surgery and age (r = -0.2755) and centre-edge (CE) angle (r = -0.2989), no correlation was found between the strength of abduction and age and radiological evaluations of CE angle and acetabular roof obliquity (ARO). Conclusion. Hip muscle strength and gait speed had recovered to their preoperative levels six months after RAO. The clinical outcome at one year was excellent, although the strength of hip flexion did not improve to the same degree as that of hip abduction and gait speed. A higher BMI may result in poorer recovery of hip muscle strength after RAO. Radiologically, acetabular coverage did not affect the recovery of hip muscle strength at one year’s follow-up. A more intensive rehabilitation programme may improve this. Cite this article: Bone Joint J 2019;101-B:1459–1463

Aims. Several studies have reported the safety and efficacy of subcapital re-alignment for patients with slipped capital femoral epiphysis (SCFE) using surgical dislocation of the hip and an extended retinacular flap. Instability of the hip and dislocation as a consequence of this surgery has only recently gained attention. We discuss this problem with some illustrative cases. Materials and Methods. We explored the literature on the possible pathophysiological causes and surgical steps associated with the risk of post-operative instability and articular damage. In addition, we describe supplementary steps that could be used to avoid these problems. Results. The causes of instability may be divided into three main groups: the first includes causes directly related to SCFE (acetabular labral damage, severe abrasion of the acetabular cartilage, flattening of the acetabular roof and a bell-shaped deformity of the epiphysis); the second, causes not related to the SCFE (acetabular orientation and poor quality of the soft tissues); the third, causes directly related to the surgery (capsulotomy, division of the ligamentum teres, shortening of the femoral neck, pelvi-trochanteric impingement, previous proximal femoral osteotomy and post-operative positioning of the leg). Conclusion. We present examples drawn from our clinical practice, as well as possible ways of reducing the risks of these complications, and of correcting them if they happen. Cite this article: Bone Joint J 2017;99-B:16–21

In this paper operations are discussed that improve the dysplastic acetabular roof in developmental dislocation of the hip (DDH) of children up to 10 years. In the first year of life acetabular dysplasia can be treated successfully by flexion-abduction splints and plaster casts in „human position“. From the second year on, only slight dysplasias can heal spontaneously or be treated conservatively. Then the steep acetabular roof has to be osteotomized and levered down to a normal angle and coverage to avoid redislocation or residual dysplasia. Different procedures have been described in the course of time. Two osteotomies are chiseling in the anterior to posterior direction. Salters innominate osteotomy levers the whole acetabulum with the lower part of the pelvis in an anterolateral direction around an axis passing through the pubic symphysis and the posterior part of the osteotomy. In Pembertons osteotomy the hinge for turning down the acetabular roof is the last, posterior, transverse cortical segment over the tri-radiate cartilage, short before the sciatic notch. Osteotomies chiseling from lateral in medial direction have been described already by Albee (1915) and Jones (1920). Lance (1925) propagated this technique in Europe. Here the acetabular roof is partially osteotomized in a thickness of 5–7 mm. Only the lateral part of the acetabulum is brought into the horizontal position. Wiberg in 1939 used this technique, but in 1953 he was the first to publish a full osteotomy what Dega called 1973 a transiliac osteotomy. Dega had originally learned the technique of Lance, but in 1963 when he reduced high dislocations after the technique of Colonna, he performed also a full transiliac osteotomy. After the Symposium of Chapchal in Basel 1965 we started in Berlin also with the complete acetabular osteotomy. With the control of an image intensifier the blade of the osteotome is driven toward the posterior rim of the tri-radiate cartilage leaving only a small bony rim above. Anteriorly the blade passes through the ant. inf. iliac spine. Posteriorly it just enters the sciatic notch. Here we check the blade position by direct palpation. The acetabulum is bent down partly in the small rim of bone left and mainly in the triradiate cartilage. Angles up to 50° have been achieved, which you cannot reach by other techniques. In the beginning we have combined after Mittelmeier and Witt this acetabuloplasty with a varus osteotomy of the femur. In our long-time follow-up (Brüning et al. 1988,1990) however, we found in almost 50% a subcapital coxa valga or a so-called head-in-neck-position of the femoral head. Then we avoided varusosteotomies and had good results without it (Pothmann). To keep the acetabular roof in the new position we used first bone wedges from the varus osteotomy, then deproteinized bone wedges from animals, and today deep frozen wedges of human femoral heads of the bone bank, sterilized at 121 degrees C for 20 min. (Ekkernkamp, Katthagen). A firm layer of cortical bone laterally is necessary. Reinvestigations have proven the stability of this material too ( Pothmann). This type of acetabular osteotomy in our and other authors opinion is the best. Salters osteotomy is not as efficient in severe dysplasia. And in older children it produces a decrease in anteversion of the acetabulum, which may limit internal rotation of the hip and cause osteoarthritis if it does not improve. In Pembertons osteotomy one cannot use the image intensifier, which is of great help to perform the osteotomy exactly and also the levering of the acetabulum to the optimal coverage. Our first long-time follow-up of children with additional varus-osteotomies (Brüning et al.) reviewed 90 hip joints in 67 children. The age at operation was in average 3.6 years, the age at follow-up 15 years. Clinical results. 98% of the patients had no pain or only occasional, no limitation of movement and normal or almost normal gait. The Trendelenburg sign was negative in 71% of the cases, grade 1 in 15.5% and grade 3 in 13.5%. Radiological evaluation. The mean value of the AC-angle (acetabular index) preoperatively was 33.8°, postoperatively normal with 16.3°. The acetabular angle of the weightbearing zone was at follow-up 9.7°, which is normal too. At the age of less than 18 years the CE angle of 25,9° was normal too, as well the instability (protrusion) index of Reimers of 12.3 % and the distance femoral head to teardrop figure with 8.8 mm. In our study group of hip dysplasia we introduced a score of normal values of hip measurements and 3 grades of deviation from normal, slightly pathological, severely pathological and extremely. When we counted normal values and slightly pathological ones together as a good result, we found for the different measurements of the acetabulum percentages mainly between 82 and 93 %. Remarkable were two measurements of the femoral neck, the epiphyseal index with only 50 % of normal and slightly pathological angles and the head-neck index with 47.7% respectively. This was due to the head-in-neck position of the femoral neck after varus osteotomy as we have mentioned already. Acetabular coverage is achieved best in transiliac osteotomies up to 10 years. Then, only by triple pelvic osteotomies the acetabulum in total can be redirected to a normal coverage. But this operation is more difficult. Residual dysplasias therefore should be treated as early as possible in the way demonstrated here

Patients with acetabular dysplasia commonly undergo peri-acetabular osteotomy after skeletal maturity to reduce the risk of the late development of osteoarthritis. Several studies have suggested that deformity of the femoral head influences the long-term outcome. We radiologically examined 224 hips in 112 patients with acetabular dysplasia and early-stage osteoarthritis. There were 103 women and nine men with a mean age of 37.6 years (18 to 49). A total of 201 hips were placed in the acetabular dysplasia group and 23 in a normal group. The centre–edge angle and acetabular head index were significantly smaller (both p < 0.001), and the acetabular angle, acetabular roof angle and roundness index were significantly greater in the acetabular dysplasia group than those in the normal group (all p < 0.001). There were significant correlations between the roundness index and other parameters. Femoral head shape may be influenced by the severity of the acetabular dysplasia. Cite this article: Bone Joint J 2013;95-B:1192–6

Objectives. We have previously investigated an association between the genome copy number variation (CNV) and acetabular dysplasia (AD). Hip osteoarthritis is associated with a genetic polymorphism in the aspartic acid repeat in the N-terminal region of the asporin (ASPN) gene; therefore, the present study aimed to investigate whether the CNV of ASPN is involved in the pathogenesis of AD. Methods. Acetabular coverage of all subjects was evaluated using radiological findings (Sharp angle, centre-edge (CE) angle, acetabular roof obliquity (ARO) angle, and minimum joint space width). Genomic DNA was extracted from peripheral blood leukocytes. Agilent’s region-targeted high-density oligonucleotide tiling microarray was used to analyse 64 female AD patients and 32 female control subjects. All statistical analyses were performed using EZR software (Fisher’s exact probability test, Pearson’s correlation test, and Student’s t-test). Results. CNV analysis of the ASPN gene revealed a copy number loss in significantly more AD patients (9/64) than control subjects (0/32; p = 0.0212). This loss occurred within a 60 kb region on 9q22.31, which harbours the gene for ASPN. The mean radiological parameters of these AD patients were significantly worse than those of the other subjects (Sharp angle, p = 0.0056; CE angle, p = 0.0076; ARO angle, p = 0.0065), and all nine patients required operative therapy such as total hip arthroplasty or pelvic osteotomy. Moreover, six of these nine patients had a history of operative or conservative therapy for developmental dysplasia of the hip. Conclusions. Copy number loss within the region harbouring the ASPN gene on 9q22.31 is associated with severe AD. A copy number loss in the ASPN gene region may play a role in the aetiology of severe AD. Cite this article: T. Sekimoto, M. Ishii, M. Emi, S. Kurogi, T. Funamoto, Y. Yonezawa, T. Tajima, T. Sakamoto, H. Hamada, E. Chosa. Copy number loss in the region of the ASPN gene in patients with acetabular dysplasia: ASPN CNV in acetabular dysplasia. Bone Joint Res 2017;6:439–445. DOI: 10.1302/2046-3758.67.BJR-2016-0094.R1

The purpose of our study was to find out the midterm results of the Müller acetabular roof reinforcement ring in primary and revision total hip arthroplasty. From 1988 to 1998, 48 total hip arthroplasties using the acetabular roof reinforcement ring (39 patients) was performed by one surgeon (PDB). We reviewed all patients who had a minimum of five year follow up. There were 37 hips (31 patients) with a mean follow up of 7 years (5 to 12 years). Acetabular deficiencies were classified according to the AAOS classification. Acetabular reconstruction was done using the Müller acetabular roof reinforcement ring with the polyethylene cup cemented to the ring, and morcellized cancellous bone graft. Müller straight stem femoral prosthesis was used in all cases for femoral reconstruction. All patients were followed up annually and outcome assessed using Harris hip score. There were 27 primary procedures and 10 revisions. 30 patients (81%) had cavitary, 2 (5%) had segmental and 5 (14%) had combined defects. Survival analysis was done with failure defined as radiological evidence of loosening of the acetabular component. Statistical analysis was done using SPSS for Windows (SPSS Inc, Chicago, Illinois). 5 patients died due to unrelated causes and 2 patients were lost for follow up. The mean Harris hip score improved from 42 preoperatively to 82 postoperatively (p< 0. 001)(Wilcoxon Signed Rank test). Both mean pain and function score showed improvement from 12 to 39 postoperatively (p< 0. 001) and 12 to 32 (p< 0. 001) respectively. 5 patients had radiological loosening of the ring. The migration rate was 13%. The cumulative survival rate at 12 years, excluding all patients who died and were lost for follow up, was 79. 3% (95% confidence interval 71. 4 to 87. 2, standard error 4). There was no statistical difference in the failure rate between primary and revision procedures (chi-square test). This series show satisfactory medium term results with Müller roof reinforcement ring and cancellous bone graft in acetabular deficiencies with poor bone stock

The term of hip dysplasia means an abnormality of shape, size or spatial configuration of the acetabulum. It also concerns the femoral head, with mutual relationships, proportions and alignment between the femoral head and the acetabulum the most crucial factors. The reason of any symptoms in hip dysplasia is the dysplastic acetabulum and its disproportion in relation to the femoral head. Dysplasia of the acetabulum appearing at puberty has been attributed to secondary “absorption” of bony acetabulum. The presence of fatigue fractures at a later age has been considered as resulting from trauma. However, the fragments of the acetabular rim should be ascribed to overloading of the rim in dysplastic hips, causing fracture and separation of its segment. They are sometimes associated with cysts in the acetabular roof. Limbus tears with or without an associated bony fragment are known to occur after traumatic dislocation of the hip but also without any history of injury. There is no explanation of their cause or their relation to acetabular dysplasia. Limbus tears have been diagnosed by arthroscopy, arthrography and CT scans. Clinical signs. No hip dysplasia in adults is really symptom-free. A casual examination applied between the painful episodes may appear so normal, that the articular origin of the pain may be doubted. In most cases pain is elicited by passive movement of the thigh into full flexion, adduction and internal rotation. This combination of movements brings the proximal and anterior parts of the femoral neck into the contact with the rim of the acetabulum, exactly at the point where the labrum is likely to be damaged. Preop imaging. An anteroposterior radiograph, or “faux profil” view of Lequesne de Seze may demonstrate a congruent but short acetabular roof (Type II) or an incongruent hip with a shallow acetabulum and a more vertical than normal acetabular roof (Type I). Type I hip is potentially or really unstable. The femoral head has migrated laterally or anteriorly or in both directions, distorting the spherical shape of actebular inlet into an oval. A simple 3-dimensional classification is recommended by myself using conventional X-ray and CT scan on equatorial level. The CE angle and sectors angle acc. Anda are used to describe the anterior, lateral and posterior coverage. To check the possibilities of reduction, the anteroposterior radiograph is made in max. abduction of the hip. To simulate the correction movement of the acetabular part we use our own “Super pelvis” software. Intra-op control. For intraoperative correction control we use a C-arm, which also controls step by step all stages of the periacetabular osteotomy. To check the final correction the X-ray of both hips is absolutely obligatory. What we should check is: the displacement of the acetabular fragment (to avoid lateralization, if necessary to make medialisation) and the positions of the anterior and posterior acetabular rim. If this is impossible with the normal a-p X-ray, the C-arm is used for achieving the “faux profil”. The computer assisted orthopaedic surgery system appears the most accurate intra-op control