AIMS. We present a retrospective study of bilateral CDH. We analysed the correlation of complications to the confounding factors. MATERIAL AND METHODS. We reviewed all bilateral CDH patients treated by the same surgeon at Southampton between 1988-2006. The patient recruitment was carried out as follows: . Group A – failed Pavlik harness;. Group B – late presentations not treated in Pavlik harness. RESULTS. The series included 50 patients (5 males; 45 females). The average age at presentation was 21 weeks (1-160). The average age at reduction was 15 months (4-45). The average follow-up was 6.7 years (4-15). 4 hips required revision due to loss of reduction. The number of surgical interventions throughout the treatment course ranged 4-12 (average – 7.3). AVN occurred in 17 hips (17%). Previous Pavlik harness treatment, CR and higher height of dislocation (HD) were associated with an increased rate of AVN. 42 pelvic (PO) and 12 femoral (FO) osteotomies (54%) were performed. CR and greater HD increased the pelvic osteotomy rate, while Pavlik harness treatment failure did not affect it. The mean AI demonstrated a gradual decline following reduction. While there was no difference between OR vs CR, and Group A vs B, the HD≥3 was associated with a significant acetabular development delay when compared to HD≤2. CONCLUSIONS. Despite the complexity of CDH cases, it is possible to achieve an acceptable level of inevitable complication (AVN – 17%, PO – 42%, FO – 12%, revision reduction – 4%). The rate of AVN was independently negatively affected by CR and prolonged immobilisation. Only the hips with initial HD of ≤2 had their acetabular index return to normal (<21°) before the age of 4 years. This is the first comprehensive analysis of bilateral CDH cases, emphasising the difficulty of treatment of this condition and providing the foundation for an outcomes-predicting system

Introduction: Fractures of the femoral stem component in total hip Arthroplasty have been a well documented complication. The incidence over recent years has decreased due to improvements in surgical technique and implant design and manufacture. Methods/Results: We report two cases of femoral stem fracture. Both occurred in CDH stems from the C-stem system (Depuy International, Leeds, UK). These are the first reported fractures in this stem. Both patients were women weighing 83kgs and 98kgs at the time of fracture giving them BMI’s of 31 and 41 respectively. In both cases the BMI had increased since the time of operation. Discussion: The design of the CDH stem is fundamentally different from the rest of the standard stems with absence of the medial strut. In addition to this factor, both stems fractured through the insertion hole which acted as a stress raiser. Finally both patients BMI’s were above 25. At the time of operation no weight limit was imposed on this prosthesis. We conclude that if possible, a standard C-stem should be inserted but if a CDH stem is used attention to patients’ weight is paramount

Fractures of the femoral stem component in total hip Arthroplasty have been a well documented complication. The incidence over recent years has decreased due to improvements in both surgical technique and implant design and manufacture. We report two cases of femoral stem fracture. Both occurred in CDH stems from the C-stem system (Depuy International, Leeds, UK). Both patients were women weighing 83kgs and 89kgs at the time of fracture. The fractures occurred at 46 and 24 months respectively. The design of the CDH stem is fundamentally different from the rest of the primary stems with absence of the medial strut. In addition to this factor, both stems fractured through the insertion hole, which acted as a stress raiser. Also of note was the fact that both patients BMI’s were above 25. No weight restrictions have been imposed by the company on this implant. We conclude that if at all possible, a primary C-stem should be inserted but if a CDH stem is used attention to patients’ weight is paramount

Aims: Evaluation of the clinical and radiological results after primary surgical treatment of CDH in children with late discovered CDH. Methods: We have studied 64 hips of 58 patients (51 female and 7 male), who were between 18 months-8 years old with late discovered CDH. The study was made between 1991–2000. Teratological and neuromuscular cases were excluded. None of the patients have had previous treatment before admission in hospital. Preoperative radiographic evaluation of the cases was made based on the Tšnnis classiþcation system (12-gr.I, 26-gr.II, 19-gr.III, 7-gr.IV). Preliminary traction was used in 5 hips (4 patients). 8 of them were treated by open reduction, 18 by open reduction and pericapsular osteotomy of the ilium described by Pemberton, 38 by combined pelvic osteotomy (29 Pem-berton osteotomy, 9 Chiari osteotomy) and femoral derotation and/or varus osteotomy (with femoral shortening in 8 cases). Postoperatively, a plaster cast was applied for 6 weeks. Average follow-up period was 6.8 years. Results: The radiological results are based on Severin Classiþcation. We obtained in 77.5% of the cases excellent, good and satisfactory results. Using the clinical rating system of Fergusson and Howard, the results were good and satisfactory in 78.8 of the cases. Avascular necrosis occurred in 6 cases, being rated as group II and III according to the Kalamchi and Mac Ewen classiþcation system. Conclusions: In case of late discovered CDH, the results of conservative treatment are not satisfactory, the surgical treatment being recommended. Four years old or elder children can be treated safely with one stage operation consisting of open reduction, pelvic osteotomy with or without femoral derotation and varus osteotomy (with shortening if it is necessary)

Aim: In Germany an ultrasound screening for CDH is recommended for all children in the þrst 6 weeks of life. We evaluated this program together with the German Association of health insurance carriers over þve years to show if an early ultrasound of the hip can reduce the number and the required operative procedures of children with CDH. Methods: From 1997 to 2002, we documented monthly all otherwise healthy children with CDH aged ten weeks up to þve years in all German orthopaedic paediatric departments with a registration card and questionnaire. Results: Overall we registered 645 children, 534 with single operative procedure. 68% received a closed reduction of the hip, 11% open, while 21% required an osteotomy of the acetabulum and/or femur. The percentage of the single operative procedures did not change over the years. The number of children, who underwent no ultrasound of the hip before diagnosis decreased from 20% in the þrst year to 10% in the last. The þrst ultrasound examination revealed no pathological þndings in 20% of the cases. Children received the þrst screening more and more at the age four to six weeks than during the þrst days of life. Nevertheless, the yearly number of cases declined by 50%. Conclusion: Despite the ultrasound-screening-program late or undiagnosed CDH still exists in our country. A possible reason can be the quality of ultrasound examination, the form of treatment as well as a later worsening of CDH and the so-called endogenous dysplasia

Aims: Stemmed cup is the evolution of Ring cup. The iliac stem is positioned in direction of sacro-iliac sin-condrosis, in axis with weight-bearing lines. It allows an optimal stability in the iliac bone avoiding the dameged acetabular region. The stemmed cup is indicated:. Ð in CDH primary implant. Ð in revision surgery (grade 2–4 according to Paproskyñs classiþcation). In severe bone loss cases (grade 3–4) we preferred to use auto or homologous bone grafts impacted to þll the bone defect. Methods:We report about 168 stemmed cup implants in 159 patients (9 bilateral cases). 37 CDH was treated as a primary implant (6 bilateral patients). The average age is 69 years (range 38–87). The mean follow up is 36 months (range 6 months Ð 6 years). 21 cases were lost at follow up. We evaluated all patients by X-rays at 1,3,6 months and every year and CT in some cases to check the iliac stem position. Results: 13 patients died because of non-related surgery. Superþcial infections 5 cases; deep infections 6 cases (two-stages revision); proximal migration < 1 cm. In 9 cases without loosening; malpositioning of the stem 7 cases; sciatic nerve palsy 5 cases (1 permanent case); DVT 3 cases. Radiolucency around stem < 2 mm. 19 cases, radiolucency around the cup in 11 cases; bone grafts resorption 10 out of 57 cases. Mean preoperative Harris Hip Score was 60; mean postoperative HHS 85. Conclusions: The good mid-term results reported conþrm that stemmed cup is a valid solution in revision surgery with mid and severe bone loss but also in CDH when conventional cup are not indicated

Objectives. There are several reports clarifying successful results following open reduction using Ludloff’s medial approach for congenital (CDH) or developmental dislocation of the hip (DDH). This study aimed to reveal the long-term post-operative course until the period of hip-joint maturity after the conventional surgical treatments. Methods. A long-term follow-up beyond the age of hip-joint maturity was performed for 115 hips in 103 patients who underwent open reduction using Ludloff’s medial approach in our hospital. The mean age at surgery was 8.5 months (2 to 26) and the mean follow-up was 20.3 years (15 to 28). The radiological condition at full growth of the hip joint was evaluated by Severin’s classification. Results. All 115 hips successfully attained reduction after surgery; however, 74 hips (64.3%) required corrective surgery at a mean age of 2.6 years (one to six). According to Severin’s classification, 69 hips (60.0%) were classified as group I or II, which were considered to represent acceptable results. A total of 39 hips (33.9%) were group III and the remaining seven hips (6.1%) group IV. As to re-operation, 20 of 21 patients who underwent surgical reduction after 12 months of age required additional corrective surgeries during the growth period as the hip joint tended to subluxate gradually. Conclusion. Open reduction using Ludloff’s medial approach accomplished successful joint reduction for persistent CDH or DDH, but this surgical treatment was only appropriate before the ambulating stage. Cite this article: Bone Joint Res 2014;3:1–6

The various surgical prosthetic solutions in coxarthrosis on a dysplastic basis were evaluated in a critical way. In our institute more than 3,750 hip prostheses were implanted from 1994 to 1999, and 366 (9.76%) were used for dysplastic coxarthrosis. This high percentage can be explained by the particular geographical position of our institute that has patients coming from the Lombardia region area where CDH is endemic. Our evaluations consider the highest number of possible parameters in order to realize which is the most modern and reliable surgical solution. Of course, each case is individual and our advantage is to have a prosthesis that is the most suitable for each patient. The number and type of prostheses used were: 27 ABG, 35 CONUS, 25 CUSTOM MADE, 7 HN, 5 MALLORY, 35 OMNIFLEX, 3 PARHOFER PLASMAPORE, 4 PERSONALISED CUSTOM MADE, 3 RIPPEN, 18 RMHS, 45 SAMO PG, 130 ZWEYMULLER, 18 P507, 6 OMNIFIT, and 5 GYPSE. From our unique perspective we can consider that in the last several years the use of a cemented prosthesis is progressively disappearing (less than 13%). The use of a cementless prosthesis in young patients (age range 20 to 65) preserves bone stock during implantation, placement and replacement when necessary. If the patient’s age and general conditions allow, we generally operate both dysplastic hips in one stage. All cases were evaluated with DEXA, which provides qualitative and quantitative data about the periprosthetic bone stock. Various parameters were studied, including restoration of normal biomechanics, centre of rotation, equalisation of limb-length, the Trendelenburg sign, and nerve complications

Introduction: Angular and torsional deviations of femur are usually combined with Congenital Dislocation of the Hip (CDH) and increase the complications of hip arthroplasty. The aim of this study is to evaluate surgical and reconstructive options for the treatment of CDH. Material and Methods: In this retrospective study, we evaluated the results and complications of 55 primary cementless total hip arthroplasties, all of whom had Crowe type-IV developmental dysplasia of the hip. The arthroplasty was performed in combination with a subtrochanteric shortening osteotomy and with placement of the acetabular component at the level of the anatomic hip center. The patients were evaluated at a mean of 8,1 years postoperatively. Results: From 1984, more than 2000 cases of arthroplasty have been performed in dysplastic hip, 565 cases had a previous femoral osteotomy; 128 cases needed correction of femoral side deformity; 64 had a greater trochanteric osteotomy. In 9 cases rotational abnormality and shortening were controlled with plate and distal femur osteotomy. 55 cases were treated by a shortening subtrochanteric osteotomy. Only non-cemented stems were used. 4 failures occurred for the incorrect fixation of the metaphysis. The fixation can be obtained only by prosthetic press-fit, but it is preferable to use metal wires. There was no sciatic injury; indeed shortening osteotomy provides an easy control of deformity and lengthening, with a maximum of 4 cm. One case was reviewed for heterotopic calcification (grade 4). One infection of the soft tissue was medically cured. There were two revisions for polyethylene failure at 8 and 12 years postoperative. Discussion: The anatomic abnormalities associated with CDH and previous femoral osteotomy increase the complexity of hip arthroplasty. We had best results with the femoral shortening subtrochanteric osteotomy where a rapid consolidation was obtained. Moreover, the functional result was better for the management of the insertion of the muscle tendons in particular the mediogluteus and also for the relatively correct positioning in favour of the reciprocal relationship of the pelvic-trochanter. The detachment of the greater trochanter associated with a metaphyseal proximal shortening, remains an effective technique for the treatment of malformations that are difficult to treat, but there is a high risk of pseudarthrosis of greater trochanter. Conclusion: Femoral shortening subtrochanteric osteotomy preserves the proximal femoral anatomy, avoids the problems associated with reattachment of the greater trochanter, and facilitating a cementless femoral reconstruction in relatively young patients

Aim

This study presents the early results of a novel procedure, both in timing and surgical technique, aimed to treat those cases of congenital hip dysplasia that present late or fail conservative treatment.

Introduction: It has been proposed that the presence of the capital femoral ossific nucleus confers protection against ischaemic injury or avascular necrosis (at the time of reduction of a congenitally dislocated hip). The current literature is contradictory.

Materials & Methods: A prospective study was undertaken of the clinical and radiological outcomes following closed or open reduction. 50 hips were included in the study. These cases had either presented late or had failed conservative treatment. In 28 hips treatment was intentionally delayed until the appearance of the ossific nucleus (but not beyond 13 months) and in 22 the ossific nucleus was present at clinical presentation. 6 hips reached the age of 13 months without an ossific nucleus appearing and progressed to treatment. The significant avascular necrosis rate (> grade 1) was 7% for closed reduction and 14% for open. However, the amended rate if hips were excluded that had failed Pavlik harness treatment was 0.0% and 9% respectively (4% overall). Further surgical procedures were necessary in 57% of hips undergoing closed reduction and 41% after open, which compares favourably with other series.

Discussion: It is concluded that the presence of the ossific nucleus is an important factor in the prevention of AVN, particularly after late closed reduction. Intentional delay in the timing of surgery does not condemn a hip to open surgery but there is a comparable rate of secondary procedures becoming necessary particularly after closed reduction. The delayed strategy to await the appearance of the ossific nucleus for previously untreated dislocation allows a simple treatment algorithm to be employed which produces good clinical and radiological outcomes. The use of the Pavlik harness has been abandoned in cases of irreducible dislocation of the hip.

Introduction: The anatomic abnormalities associated with the dysplastic hip increase the complexity of hip arthroplasty, in addition previous femural osteotomy can deformate proximal femur.

Despite the fact that uncemented cup and stems are specifically designed for dysplasia to recover the true acetabular region in Crowe IV and sometimes Crowe III additional surgical procedure are required.

Purpose of the study is to analize surgical procedure and then reconstruction options on severe hip dysplasia.

Materials and methods: From 1984 till today 2308 cases of arthroplasty were performed in dysplastic hip, 565 cases have a previous femoral osteotomy; out of these 2308 cases 128 cases need treatment for corrections of femural side deformity.

64 cases were subjected to a greater trochanteric osteotomy. In 12 cases proximal femural shortening was associated. In 9 cases rotational abnormality and shortening were controlled with a distal femur osteotomy.

55 cases were treated by a shortening subtrochanteric osteotomy that allows corrections of any deformity. Only uncemented stems were used and in the majority of cases a specific device for displastic hip (Wagner Conus produced by Zimmer).

Discussion: Long-term results in these patients are steadily inferior to that in the general population (70% survival at 15 yrs). On femural side early failures are the reflection of learning curve and are due to insufficient fixation of the osteotomy.

Despite this, the more promising outcomes are concerning shortening subtrochanteric osteotomy with uncemented stem but only early and mid-term data are available.

Introduction

The anatomic abnormalities associated with the dysplastic hip increase the complexity of hip arthroplasty, in addition previous femural osteotomy can deformate proximal femur. Despite the fact that uncemented cup and stems are specifically designed for dysplasia to recover the true acetabular region in Crowe IV and sometimes Crowe III additional surgical procedure are required. Purpose of the study is to verify surgical procedures and explore reconstruction options on severe hip dysplasia.

Pelvic bone defect in patients with severe congenital dysplasia of the hip (CDH) lead to abnormalities in lumbar spine and lower limb alignment that can determine total hip arthroplasty (THA) patients' outcome. These variables may be different in uni- or bilateral CDH. We compared the clinical outcome and the spinopelvic and lower limb radiological changes over time in patients undergoing THA due to uni- or bilateral CHD at a minimum follow-up of five years. Sixty-four patients (77 hips) undergoing THA due to severe CDH between 2006 and 2015 were analyzed: Group 1 consisted of 51 patients with unilateral CDH, and group 2, 113 patients (26 hips) with bilateral CDH. There were 32 females in group 1 and 18 in group 2 (p=0.6). The mean age was 41.6 years in group 1 and 53.6 in group 2 (p<0.001). We compared the hip, spine and knee clinical outcomes. The radiological analysis included the postoperative hip reconstruction, and the evolution of the coronal and sagittal spinopelvic parameters assessing the pelvic obliquity (PO) and the sacro-femoro-pubic (SFP) angles, and the knee mechanical axis evaluating the tibio-femoral angle (TFA). At latest follow-up, the mean Harris Hip Score was 88.6 in group 1 and 90.7 in group 2 (p=0.025). Postoperative leg length discrepancy of more than 5 mm was more frequent in group 1 (p=0.028). Postoperative lumbar back pain was reported in 23.4% of the cases and knee pain in 20.8%, however, there were no differences between groups. One supracondylar femoral osteotomy and one total knee arthroplasty were required. The radiological reconstruction of the hip was similar in both groups. The PO angle improved more in group 1 (p=0.01) from the preoperative to 6-weeks postoperative and was constant at 5 years. The SFP angle improved in both groups but there were no differences between groups (p=0.5). 30 patients in group 1 showed a TFA less than 10º and 17 in group 2 (p=0.7). Although the clinical outcome was better in terms of hip function in patients with bilateral CDH than those with unilateral CDH, the improvement in low back and knee pain was similar. Patients with unilateral dysplasia showed a better correction of the PO after THA. All spinopelvic and knee alignment parameters were corrected and maintained over time in most cases five years after THA

Total hip arthroplasty (THA) for congenital hip dysplasia (CDH) presents a challenge. In high-grade CDH, key surgical targets include cup placement in the anatomical position and leg length equality. Lengthening of more than 4 cm is associated with sciatic nerve injury, therefore shortening osteotomies are necessary. We present our experience of different shortening osteotomies including advantages and disadvantages of each technique. 89 hips, in 61 pts (28 bilateral cases), for high CDH were performed by a single surgeon from 1997 to 2022. 67 patients were female and 22 were male. Age ranged from 38 to 68 yrs. In all patients 5–8cm of leg length discrepancy (LLD) was present, requiring shortening femoral osteotomy. 12 patients underwent sequential proximal femoral resection with trochanteric osteotomy, 46 subtrochanteric, 6 midshaft, and 25 distal femoral osteotomies with simultaneous valgus correction were performed. All acetabular prostheses were placed in the true anatomical position. We used uncemented high porosity cups. Patients were followed up for a minimum of 12 months. All osteotomies healed uneventfully except 3 non-unions of the greater trochanter in the proximal femur resection group. No femoral shaft fractures in proximally based osteotomies. No significant LLD compared to the unaffected or reconstructed side. 2 patients suffered 3 and 5 degrees malrotation of the femur in the oblique sub-trochanteric group. 3 patients suffered transient sciatic nerve palsies. Shortening femoral osteotomies in the treatment of DDH are necessary to avoid injury to the sciatic nerve. In our series, we found transverse subtrochanteric osteotomies to be the most technically efficient, versatile and predictable in their clinical outcome, due to the ability to correct rotation and preserve the metaphyseal bone integrity, allowing for better initial stem stability. Distal femoral osteotomies allowed for controllable correction of valgus knee deformity

Since September 1964, neonates born in New Plymouth have undergone clinical examination for Neonatal Instability of the Hip (NIH) in a structured clinical screening programme. Forty one thousand, five hundred and sixty three babies were born during the period of this study, of which 1,638 were diagnosed as having unstable hips. Six hundred and thirty three with persisting instability were splinted (1.6%), with five hips failing splintage. In addition, three unsplinted hips progressed to CDH, and there were four late-presenting (walking) cases of CDH, giving an overall failure rate for the programme of 0.29 per 1000 live births, with a late-presenting (walking) CDH incidence of 0.1 per 1000 live births. This study confirms that clinical screening for NIH by experienced orthopaedic examiners significantly lowers the incidence of late-presenting (walking) CDH

Aim: In Germany an ultrasound screening examination to determine CDH is recommended for all children in the first 6 weeks of life. We evaluated this ultrasound-screening-program together with the German Association of health insurance carriers over five years to show if an early ultrasound of the hip can reduce the number and the required operative procedures of children with CDH. Methods: From 1997 to 2002, we documented monthly all children with CDH aged ten weeks up to five years from all German paediatric orthopaedic departments with a registration card and questionnaire. Children with neuromuscular diseases or teratologic dislocation of the hip, enrolled in out-patient treatment programs, as well as children born abroad were excluded. Results: Overall we registered 645 children, 534 with single operative procedure. 68% received a closed reduction of the hip, 11% open, while 21% required an oste-otomy of the acetabulum and/or femur. The percentage of the single operative procedures did not change over the years. The number of children, who underwent no ultrasound of the hip before diagnosis decreased from 20% in the first year to 10% in the last. The first ultrasound examination revealed no pathological findings in 20% of the cases. During the five years children received the first screening more and more at the age four to six weeks than during the first days of life. Nevertheless, the yearly number of cases declined by 50%. Conclusion: Despite the German ultrasound-screening-program late or undiagnosed CDH still exists in our country. A possible reason can be the quality of ultrasound examination, the form of treatment as well as a later worsening of CDH and the so-called endogenous dysplasia. The aim must be the improvement of diagnosis and treatment

Aims: In opposition to stemmed THR, Hip Resurfacing offers considerable advantages like bone preservation, however a correction of the pathological rotation and offset of the upper femur in higher grade CDH cases is not possible during implantation without subtrochanteric osteotomy. The aim of this study is the comparison of short term clinical and radiological results of Hip Resurfacing in higher grade CDH without osteotomy and primary osteoarthritis to examine if the clinical results are affected because of this disadvantage. Methods: Comparison of the clinical and radiological results of 38 BHR arthroplasties with acetabular bone grafting in CDH cases Eftekhar grade B and 76 BHR in primary osteoarthritis, AVN or Epiphyseolysis capitis femoris cases with a follow up from 6 months to 3 years. Results: Up to one year postoperatively the BHR with acetabular grafting showed slightly lower Harris Hip Scores than the primary osteoarthritis cases with differences up to 5 points. In opposition to that the range of motion and the number of positive Trendelenburg signs were not different. Also a difference in the rate of complications was not detectable. Conclusions: In our opinion the slightly slower rehabilitation of BHR with acetabular grafting in higher grade CDH depended on the partial weight bearing over 3 months postoperatively and the higher number of cases with an affected contralateral hip but not on the resultant pathology

Total hip joint replacement (THJR) for high riding congenital hip dislocation (CDH) is often performed in young patients, and presents unique problems with acetabular cup placement and leg length inequality. A database and the NZ Joint Registry were used to identify 76 hips in 57 patients with a diagnosis of CDH who underwent THJR in the Wellington region between 1994 and 2015. Records and radiographs of 46 hips in 36 patients classified pre-operatively as Crowe II, III or IV were reviewed. Surgical technique used a direct lateral approach, the uncemented acetabular component was located in the anatomic hip center and a primary femoral stem was used in all but one hip. Whether a step-cut sub-trochanteric femoral osteotomy was performed depended on degree of correction, tension on the sciatic nerve, and restoration of leg length. For the 36 patients classified as Crowe II or higher, the average age at operation was 44 years (26 – 66), female:male ratio was 4.5:1 and follow-up averaged 10 years (2 – 22.3). Of the 15 hips classified as Crowe IV, 10 required a step-cut sub-trochanteric femoral osteotomy to shorten the femur, but 5 were lengthened without undo tension on the sciatic nerve. Nine Crowe IV hips received a conventional proximally coated tapered primary femoral component. Oxford hip scores for 76% of patients was excellent (> 41/48), and 24% had good scores (34 – 41). All femoral osteotomies healed. Five hips have been revised, one at 2 years for femoral loosening, one at 5 years for dislocation, two at 12 years for liner exchanges, and one at 21 years for femoral loosening. THJR using primary prostheses for CDH can provide durable long-term results

Evaluation of the anatomical features, details of surgical technique and results of the THA in patients with CDH (type C1 and C2 by G. Hartofilakidis). From 2001 to 2016 years one surgical team performed 683 THA in patients with CDH. We retrospectively studied 561 total hip arthroplasties in 349 patients, follow-up rate was 82.1%, from 12 to 188 months (mean 69.4). The results were evaluated by clinical examination, X-rays analysis, Harris Hip Score. Unilateral high hip dislocation was observed in 175 patients (31.2%), in these cases often have underdeveloped half of the pelvis on the side of the dislocation. Type C1 was observed in 326 cases and type C2 – in 235 cases. Type C1 in comparison with C2 has less leg length discrepancy, developed shape of proximal femur, presence of supraacetabular osteophyte. The mean displacement of femoral head was 47.6 mm (from 29 to 55) for C1 and 63.4 mm (from 41 to 78) for C2. Average offset in C1 was 50.1 mm (37–63) and in C2 − 44.3 mm (34–52). Shortening osteotomy by T. Paavilainen performed in 165 cases (50.6%) with C1 dysplasia and in 235 cases (100%) with C2. The features of surgical technique were small size of the cups with obligatory additional screw fixation of the cup and small offset of the stems. The cup was positioned into the true acetabulum in 99.1% cases of C2 type, for C1 – only 69.0%). The cups size 44 mm were used in 97.3% cases for type C2 and in 78.6% cases for type C1. For shortening osteotomy in 76.3% cases Wagner Cone stems were used. Early complications included 9 dislocations (1.6%), 8 femoral nerve neuropathies (1.4%) and 3 infections (0.5%). There is no sciatic nerve palsy. Late complications included dislocation in two hips (1.1%), nonunion of the greater trochanter (8.4%), aseptic loosening of the femoral component − 2 (0.8 %), aseptic loosening of the cup − 11 (1.6%). Average Harris Hip score improved from 39.5 to 83.6 with unsignificant diffence between types C1 and C2 (from 37.3 to 81.4 and from 40.4 to 85.1 consequently). Revision rate was 2.1% for type C1 and 5.5% for type C2. Hip replacement surgery in patients with high hip dislocation is very challenging. Type C2 dysplasia has only one surgical option with good long-term results – placement of the cup into the true acetabulum and shortening osteotomy. Its advantages include leg length alignment and decreased risk of sciatic nerve injury. Type C1 dysplasia presents more heterogenic group of patients and allows to use several surgical options – different placement of the cup and surgical approach without shortening osteotomy. Functional results in patients with type C1 are a little bit worse in comparison with type C2, but C1 had less risk of complications. The main problem of shortening osteotomy by Paavilainen is delayed union and non-union of great trochanter