Aims

The aim of this study was to evaluate the suitability of the tapered cone stem in total hip arthroplasty (THA) in patients with excessive femoral anteversion and after femoral osteotomy.

Aims

Perthes’ disease (PD) often results in femoral head deformity and leg length discrepancy (LLD). Our objective was to analyze femoral morphology in PD patients at skeletal maturity to assess where the LLD originates, and evaluate the effect of contralateral epiphysiodesis for length equalization on proximal and subtrochanteric femoral lengths.

Aims. Total hip arthroplasty (THA) in patients with post-polio residual paralysis (PPRP) is challenging. Despite relief in pain after THA, pre-existing muscle imbalance and altered gait may cause persistence of difficulty in walking. The associated soft tissue contractures not only imbalances the pelvis, but also poses the risk of dislocation, accelerated polyethylene liner wear, and early loosening. Methods. In all, ten hips in ten patients with PPRP with fixed pelvic obliquity who underwent THA as per an algorithmic approach in two centres from January 2014 to March 2018 were followed-up for a minimum of two years (2 to 6). All patients required one or more additional soft tissue procedures in a pre-determined sequence to correct the pelvic obliquity. All were invited for the latest clinical and radiological assessment. Results. The mean Harris Hip Score at the latest follow-up was 79.2 (68 to 90). There was significant improvement in the coronal pelvic obliquity from 16.6. o. (SD 7.9. o. ) to 1.8. o. (SD 2.4. o. ; p < 0.001). Radiographs of all ten hips showed stable prostheses with no signs of loosening or migration, regardless of whether paralytic or non-paralytic hip was replaced. No complications, including dislocation or infection related to the surgery, were observed in any patient. The subtrochanteric shortening osteotomy done in two patients had united by nine months. Conclusion. Simultaneous correction of soft tissue contractures is necessary for obtaining a stable hip with balanced pelvis while treating hip arthritis by THA in patients with PPRP and fixed pelvic obliquity. Cite this article: Bone Jt Open 2021;2(9):696–704

Aims

The main aims were to identify risk factors predictive of a radiolucent line (RLL) around the acetabular component with an interface bioactive bone cement (IBBC) technique in the first year after THA, and evaluate whether these risk factors influence the development of RLLs at five and ten years after THA.

Aims. Complex total hip arthroplasty (THA) with subtrochanteric shortening osteotomy is necessary in conditions other than developmental dysplasia of the hip (DDH) and septic arthritis sequelae with significant proximal femur migration. Our aim was to evaluate the hip centre restoration with THAs in these hips. Methods. In all, 27 THAs in 25 patients requiring THA with femoral shortening between 2012 and 2019 were assessed. Bilateral shortening was required in two patients. Subtrochanteric shortening was required in 14 out of 27 hips (51.9%) with aetiology other than DDH or septic arthritis. Vertical centre of rotation (VCOR), horizontal centre of rotation, offset, and functional outcome was calculated. The mean followup was 24.4 months (5 to 92 months). Results. The mean VCOR was 17.43 mm (9.5 to 27 mm) and horizontal centre of rotation (HCOR) was 24.79 mm (17.2 to 37.6 mm). Dislocation at three months following acetabulum reconstruction required femoral shortening for offset correction and hip centre restoration in one hip. Mean horizontal offset was 39.72 (32.7 to 48.2 mm) compared to 42.89 (26.7 to 50.6 mm) on the normal side. Mean Harris Hip Score (HHS) of 22.64 (14 to 35) improved to 79.43 (68 to 92). Mean pre-operative shortening was 3.95 cm (2 to 8 cm). Residual limb length discrepancy was 1.5 cm (0 to 2 cm). Sciatic neuropraxia in two patients recovered by six months, and femoral neuropraxia in one hip recovered by 12 months. Mean Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) was 13.92 (9 to 19). Mean 12-item short form survey (SF-12) physical scores of 50.6 and mental of 60.12 were obtained. Conclusion. THA with subtrochanteric shortening is valuable in complex hips with high dislocation. The restoration of the hip centre of rotation and offset is important in these hips. Level of evidence IV. Femoral shortening useful in conditions other than DDH and septic sequelae. Restoration of hip centre combined with offset to be planned and ensured

Aims

The modified Dunn procedure has the potential to restore the anatomy in hips with severe slipped capital femoral epiphyses (SCFE). However, there is a risk of developing avascular necrosis of the femoral head (AVN). In this paper, we report on clinical outcome, radiological outcome, AVN rate and complications, and the cumulative survivorship at long-term follow-up in patients undergoing the modified Dunn procedure for severe SCFE.

Aims

The aims of this study were to review the surgical technique for a combined femoral head reduction osteotomy (FHRO) and periacetabular osteotomy (PAO), and to report the short-term clinical and radiological results of a combined FHRO/PAO for the treatment of selected severe femoral head deformities.

Aims

There is no consensus about the best method of achieving equal leg lengths at total hip arthroplasty (THA) in patients with Crowe type-IV developmental dysplasia of the hip (DDH). We reviewed our experience of a consecutive series of patients who underwent THA for this indication.

Introduction. In DDH cases often have high anteversion. They also often have high hip center. THA for those cases sometimes requires subtrochanteric derotational/shortening osteotomy. To achieve good results of the surgery, accurate preoperative planning based on biomechanics of the high anteversion cases, method for accurate application of the plan, and stable fixation are very important. At ISTA 2008, we have reported that the location of the anteversion exist several centimeters below the lesser trochanter. Independently from the extent of anteversion, femoral head, grater trochanter, and lesser trochanter are aligned in the same proportion. We have also reported in 2007, in improper high anteversion cases, many cases grow osteophytes posterior side of femoral head to reduce it functionally. In 2014, we reported about development of the stem for subtrochanteric osteotomy. (ModulusR)[Fig.1] In the present study, we established systematic planning way for estimate proper derotation and shortening and apply it for the surgery. Methods. Leg alignment during walking were well observed. According to the CT, 3D geometry of the femur, anteversion in hip joint and its compensation by the osteophyte, and knee rotation were measured. It was divided into proximal part and distal part at several centimeter below the lesser trochanter. Adequate hip local anteversion was determined by local original anteversion – compensation if IR-ER can be done. Keeping that anteversion for the proximal part, distal part was rotated as knee towards front. Thus derotation angle was decided. Using 3D CAD (Magics®) proper size of Modulus R was selected and overlapping with canal was extracted then its center of gravity was calculated. This level is decided as the height of osteotomy to obtain equal fixation to both proximal and distal part.[Fig.2] If the derotation angle is less than 15 degree, modular neck adjustment was selected first. By trial reduction and motion test, according to the instability osteotomy was performed. In the high hip center cases, original hip center was reconstructed. Shortening length was determined not to make leg elongation more than 3cm. ModulusR were used for the replacement and fixation of the osteotomy. Results. Eight cases were operated with this procedures. Standard Modulus was used in one case. In the case rotational fixation was well obtained but proximal stress shielding happened. ModulusR was used in other seven cases. In one ModulusR case vertical clack; which was fixed by metal band; happened in proximal part by the repeated rotational adjustment. But in all ModulusR cases, weight baring could be started in 1 week and good union was observed. Every patient feels knee direction became better than before.[Fig.3,4]. Discussion. In intraoperative stability test, much better stability was obtained after derotational osteotomy was done than the adjustment only by modular neck direction. Reducing anteversion by osteotomy was supposed to have advantage. Limitation of this paper is that the adequate hip local anteversion was estimated from femoral geometry and osteophytes and knee direction during walking. Future improvement would to use 2D-3D matching while walking to determine accurate hip local anteversion

Introduction. Total hip arthroplasty (THA) for a highly dislocated hip can be problematic and technically challenging. Our previous study on cemented THA with subtrochanteric femoral shortening osteotomy revealed a high incidence (20%) of non-union. Therefore, in 2008, we introduced reverse hybrid THA using S-ROM stem for the treatment of a highly dislocated hip. The purpose of this study was to assess the short-term clinical outcomes of this new method. Patients and methods. Between 2008 and 2014, 13 consecutive reverse hybrid THAs were performed on nine female patients with highly dislocated hips. The average age at the time of operation was 66 years (range, 55–85 years). The acetabular component was fixed in the true acetabulum with bone cement. Transverse osteotomy was performed below the lesser trochanter to shorten the femur and to prevent over-lengthening. The proximal sleeve of the S-ROM stem was then fixed within the proximal fragment, and the distal fin provided rotational stability of the distal fragment. Thus, the two fragments were fixed to each other with the S-ROM stem, and the resected segment was longitudinally cut for grafting at the junction. The postoperative follow-up period was an average of 4 years (range, 1–7 years), and no patients were lost. Preoperative and final Japanese Orthopaedic Association (JOA) hip score, operation time, bleeding amount, intraoperative and postoperative complications, bone healing at the osteotomy site, implant loosening, and revision surgery were retrospectively investigated. Results. The mean JOA hip score improved from 56 points preoperatively to 82 points postoperatively. The operation time and amount of bleeding were an average of 208 min and 643 g, respectively. The mean length of femoral resection was 4 cm (range, 2–6 cm), and the tip of the greater trochanter migrated an average distance of 7 cm (range, 5–9 cm) distally. The calculated limb lengthening was an average of 3 cm (range, 2–4 cm). Intraoperative fracture was seen in two patients, but no repeat operation was required. Two patients experienced postoperative dislocation in their hips, but additional surgery was not necessary. Postoperative nerve palsy did not occur in any patient, and all the osteotomy sites showed complete bone union. There was no implant loosening seen in any patient, and there was also no need for revision surgery. Discussion and conclusions. To achieve satisfactory outcomes with this method, resection of necessary and sufficient length of femur and accomplishment of adequate fixation between the proximal and distal fragments are necessary. In this study, dislocation occurred in two patients, and no nerve palsy was seen. Larger femoral heads may be recommended to eradicate dislocations. In cases where metaphysis of the femur is hypoplastic or the medullary canal is wide, reaming and stem insertion should be carefully performed. In this series, no additional surgery was required for the intra- and post-operative complications, and the osteotomy sites achieved bone union in all patients. Therefore, we recommend the use of this method, although longer follow-up periods are necessary

Aim. To assess the survivorship of a tapered fluted Titanium monoblock stem in conjunction with subtrochanteric shortening for patients with High Dislocation performed at 2 centres. Methods. This was a retrospective study of 84 hips in 52 patients between two centres. All patients had a high dislocation. Thirty five patients had bilateral dysplasia. All patients had total hip arthroplasty with a subtrochanteric shortening osteotomy. The acetabular component was placed at the level of the anatomic hip centre. The femoral component was the “Wagner Cone prosthesis” which is a monoblock Titnium Alloy stem, tapered and fluted. The acetabular component varied. All patients had a follow up examination with a Harris Hip Score and a plain radiograph. The radiographs were assessed for osteotomy complications, change in stem position, evidence of loosening, heterotopic ossification & stress shielding if any. Notes were reviewed for complications. Results. The mean age at operation was 55 yrs (range 20–83). The mean follow up was 9 years (range3–20). Eight patients were lost to follow up (16%). All the rest of the femoral components survived that were available for follow up −84% (worst case scenario). Six patients (7.8%) had an early complication that needed a reoperation. The Mean Harris Hip Score (HHS) improved from 42 points to 88 points. Conclusion. The success rate of patients undergoing Cementless Arthroplasty using the Wagner cone stem in conjunction with a subtrochanteric shortening osteotomy is very high. The complication rate is however larger than in the normal population

Down’s syndrome is associated with a number of musculoskeletal abnormalities, some of which predispose patients to early symptomatic arthritis of the hip. The purpose of the present study was to review the general and hip-specific factors potentially compromising total hip replacement (THR) in patients with Down’s syndrome, as well as to summarise both the surgical techniques that may anticipate the potential adverse impact of these factors and the clinical results reported to date. A search of the literature was performed, and the findings further informed by the authors’ clinical experience, as well as that of the hip replacement in Down Syndrome study group. The general factors identified include a high incidence of ligamentous laxity, as well as associated muscle hypotonia and gait abnormalities. Hip-specific factors include: a high incidence of hip dysplasia, as well as a number of other acetabular, femoral and combined femoroacetabular anatomical variations. Four studies encompassing 42 hips, which reported the clinical outcomes of THR in patients with Down’s syndrome, were identified. All patients were successfully treated with standard acetabular and femoral components. The use of supplementary acetabular screw fixation to enhance component stability was frequently reported. The use of constrained liners to treat intra-operative instability occurred in eight hips. Survival rates of between 81% and 100% at a mean follow-up of 105 months (6 to 292) are encouraging. Overall, while THR in patients with Down’s syndrome does present some unique challenges, the overall clinical results are good, providing these patients with reliable pain relief and good function.

Cite this article: Bone Joint J 2013;95-B, Supple A:41–5.

Background. Subtrochanteric femoral shortening and corrective osteotomy are considered to be an integral part of total hip arthroplasty for a completely dislocated hip or severe deformity of the proximal femur. A number of alternative femoral osteotomy techniques, transverse, oblique, step-cut, and V-shaped, have been described. Becker and Gustilo reported the “double-chevron subtrochanteric shortening derotational femoral osteotomy,” which is reasonable in that the osteotomy site is torsionally more stable and can be stabilized with a shorter stem. We have simplified this procedure, and performed it without a trochanteric osteotomy. We describe a simplified double-chevron osteotomy and provide the clinical results from a series of 22 successful procedures. Methods. In this series, we performed 22 cementless total hip arthroplasties combined with double-chevron subtrochanteric osteotomies between 1997 and 2002. There were 17 females and 2 males. Their average age at the time of the operation was 59 years old (range, 41–74 years old). Thirteen of these hips were congenitally dislocated hips (Crowe IV), and 8 hips were after proximal femoral osteotomies using a procedure described by Schanz or valgus osteotomy, and 1 hip was an ankylosed hip in malposition. Results. The mean length of the operation was 128 minutes (range, 80–215 minutes). The mean total blood loss was 1442 g (range, 809–2007 g), which included both the intraoperative blood loss and postoperative blood loss. After an average of 7.6 years of follow-up, the Japanese Orthopaedic Association Hip Score improved from 48 to 79. The mean amount of intraoperative femoral resection was 29 mm (range, 10–45 mm). The postoperative highest point of the greater trochanter was lowered by a mean of 50 mm (range, 6–74 mm) compared with its preoperative point on the radiograph. The calculated measurement (lowered greater trochanter minus intraoperative femoral resection) of leg lengthening was a mean 21 mm (range, −4–51 mm). Two acetabular component migrated, and one case required revision surgery. The other components showed no evidence of migration or loosening. There were radiolucent lines of less than 2 mm thickness in zones 1, 2, and 3 in one acetabular as previously mentioned revision case. One femoral component had subsidence 3 mm. Four femoral components had radiolucencies. One osteotomy site failed union and was varus deformity. After 6 years after the operation, the case required revision using cementless long stem. All femoral components achieved fixation with an optimal interface at the latest follow-up. Three types of complications were observed. There were no cases of neurologic abnormality, infection. There were 4 early dislocations, 3 proximal splits, and 1 nonunion at the osteotomy site. All femoral fragment fractures during the operation and all dislocations after the operation were in the Crowe IV group. Conclusions. Our study shows that double-chevron subtrochanteric osteotomy provided acceptable results for subtrochanteric femoral shortening and corrective osteotomy. The operation procedure is simple and the operation time is much shorter. However, THA combined with subtrochanteric osteotomy is a technically demanding treatment option

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

Restoration of an anatomical hip centre frequently requires limb lengthening, which increases the risk of nerve injury in the treatment of Crowe 4 DDH. The objective was to perform a prospective evaluation of SDTSO with Cemented Exeter Femoral Component.

15 female patients (18 hips – 3 bilateral) with a mean age at time of operation of 51 years were followed-up for a mean of 77 months (11 to 133). 16 cemented and 2 uncemented acetabular components were implanted. Exeter cemented DDH stems were used in all cases. No patient was lost to follow-up.

Charnley-d'Aubigné-Postel scores for pain, function and range of movement were improved from a mean of 2, 2, 3 to 5, 4, 5 respectively. One osteotomy failed to unite at 14 months and was revised successfully. Clinical healing was achieved at a mean of 6 months and radiological at a mean of 9 months. The mean length of the excised segment was 3cm and the mean true limb lengthening was 2cm. A 3.5mm DCP plate with unicortical screws was used to reduce the osteotomy, and intramedullary autografting was performed in all cases. Mean subsidence was 1mm and no stem was found loose at the latest follow-up. No sciatic nerve palsy was observed and no dislocation.

Cemented Exeter femoral components perform well in the treatment of Crowe IV DDH with SDTSO. Transverse osteotomy is necessary to achieve derotation and reduction can be maintained with a DCP plate. Intramedullary autografting prevents cement interposition at the osteotomy site.

Restoration of an anatomical hip centre frequently requires limb lengthening, which increases the risk of nerve injury in the treatment of Crowe 4 Developmental Dysplasia of the Hip (DDH). Prospective evaluation of the use of subtrochanteric derotational femoral shortening with a cemented Exeter stem. 15 female patients (18 hips – 3 bilateral) with a mean age at time of operation of 51 years followed-up for a mean of 114 months (range 52 to 168). 16 cemented and 2 uncemented acetabular components were implanted. Exeter cemented DDH stems were used in all cases. No patient lost to follow up. All 18 Crowe IV hips reviewed. Charnley-D’Aubigne-Postel score for pain, function and range of movement were improved from a mean of 2-2-3 to 5-4-5 respectively. One osteotomy failed to unite at 14 months and revised successfully. Clinical healing was achieved at a mean of 6 months while radiological evidence of union at a mean of 9 months. The mean length of the excised segment was 3 cm and the mean true limb lengthening was 2 cm. 3.5mm DCP plate with unicortical screws was used to reduce the osteotomy, and intramedullary autografting performed in all cases. Mean subsidence was 1 mm and no stem was found to be loose at the latest follow up. No sciatic nerve palsy was observed and there were no post-operative dislocations. Cemented Exeter femoral components perform well in the treatment of Crowe IV DDH with when a subtrochanteric derotational shortening osteotomy (SDSO) was necessary. A transverse osteotomy is necessary to achieve derotation and reduction can be maintained with a DCP plate. Intramedullary autografting prevents cement interposition at the osteotomy site and promotes healing

Background: the purpose of this paper is to evaluate the functional and clinical results of the developmental high dislocated hips after subtrochanteric transverse shortening osteotomy fixed axially and rotationally by cementless femoral stem and the asetabular component placed into the anatomical place. Methods: in a retrospective study, we evaluated the results and complications of twenty-four consecutive primary cementless total hip arthroplasty in eighteen patients (sixteen female and two male) all of whom had Crowe IV (Hartofilakidis type III) high dislocations. The arthroplasty was performed in combination with a subtrochanteric transverse shortening osteotomy and Zweymüller femoral stem(SL plus) without any fixation instruments for the osteotomy site and with placement of the acetabular component at the level of anatomic hip center. All of the patients were evaluated at a mean of 4 years postoperatively. Results: the mean Harris Hip score increased from 17.25 points preoperatively to 84.87 points at the time of final follow up (p< 0.01). Seven of the twenty four hips had an early or late complications and/or reoperations. None of the subtrochanteric osteotomies were followed by non-union and no other complications concerning the femoral site is seen. There was one instance of isolated loosening of asetabuler component. Two hips dislocated postoperatively which were treated by closed reduction and bracing for 12 weeks. One siatic neurapraxic injury was identified which resolved within 6 months’ time. Intraoperative femoral cracks were seen in three hips. One of them on the proximal part (trochanteric site) and the other two on the distal femur. All were fixed by cerclage and cables without any further pain and complications. Conclusions: subtrochanteric shortening osteotomy and cementless total hip arthoplasty for the treatment of developmental dysplasia and dislocations of the hip were associated with high rates of successful fixation of the femoral component and the asetabulum. The osteotomy site has a healing potential within the eight weeks’ time without any complications. The mean Harris hip score was 84.87 points. The complication rate is higher than that associated with primary total hip arthroplasty for the degenerative arthritis

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

This paper reviews the current knowledge relating to the management of adult patients with congenital hip disease. Orthopaedic surgeons who treat these patients with a total hip replacement should be familiar with the arguments concerning its terminology, be able to recognise the different anatomical abnormalities and to undertake thorough pre-operative planning in order to replace the hip using an appropriate surgical technique and the correct implants and be able to anticipate the clinical outcome and the complications.