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(iii) Surgical tactics in the difficult primary hip replacement
MINI-SYMPOSIUM: PRIMARY HIP REPLACEMENT
(iii) Surgical tactics in the difficult primary hip replacement
Conditions associated with complex primary total hip arthroplasty either as a result of the primary pathology or in combination with previous treatments Developmental dysplasia Perthes Slipped upper femoral epiphysis Avascular necrosis Severe primary osteoarthritis Aggressive rheumatoid arthritis Protrusio acetabuli Neuromuscular conditions Fractures about the hip Skeletal dysplasias Septic arthritis Paget’s disease
Christopher J Brew
Abstract The term complex primary total hip arthroplasty (THA) is used when THA is performed on patients with any combination of abnormal anatomy, bone loss and compromised soft tissues. This is often as a result of the development of secondary osteoarthritis complicating an underlying primary pathology. Those most commonly associated are developmental hip dysplasia, protrusio acetabuli, skeletal dysplasias, previous fractures or surgical procedures about the hip and neuromuscular conditions, but this is by no means an exhaustive list. The importance of preoperative planning and the use of reconstructive techniques including bone grafting, as well as the use of modular and customized implants to overcome these significant surgical challenges, are discussed.
Table 1
Preoperative assessment The indications for surgery include uncontrolled pain with functional impairment and radiographic evidence of secondary degenerative change. Contraindications include the presence of infection and a surgically unfit patient. A detailed history should be taken including any known diagnosis of childhood hip problems and any previous operations on the hips. A standard examination of the hip should be performed, paying particular attention to true and apparent leg length discrepancy, which can often be significant, Thomas’s test for fixed flexion deformity, range of motion and any neuromuscular abnormality should be carefully assessed. In the primary setting a significant recent leg length change that is noticed by the patient should alert the surgeon to severe progressive bone loss and ensure an up to date radiograph is available. A plain anteroposterior (AP) radiograph of the pelvis centred on the symphysis with a marker ball for templating should be obtained (Figure 1a). Depending on the underlying pathology a true lateral radiograph can be useful to assess for abnormal bone alignment of the proximal femur, which is often present after previous corrective osteotomies. Furthermore it can be used to assess for increased femoral neck anteversion, as may regularly be seen with dysplastic hips. Computed Tomography (CT) can be utilized in cases of significantly altered anatomy and is useful for estimating the size of bony defects, the integrity of the anterior and posterior columns and any deficiencies in the walls of the acetabulum, thereby informing detailed planning for reconstruction.
Keywords acetabular reconstruction; complex primary total hip arthroplasty; femoral osteotomy; impaction bone grafting; structural bone graft
Introduction Primary total hip arthroplasty (THA) is one of the most successful and rewarding operations performed, with approximately 77 000 carried out every year in the United Kingdom.1,2 The vast majority of these procedures are carried out for primary osteoarthritis, but a smaller proportion of primary cases are performed to treat secondary osteoarthritis resulting from other underlying pathologies. (Table 1). The very nature of these pathologies means that the surgeon can be faced with performing a hip replacement on a patient with any combination of compromised bone stock, abnormal primary or secondary anatomy as a result of previous treatments and compromised soft tissue states. Such procedures are therefore termed complex primary THA and can present significant surgical challenges. Often some of the principles and techniques used in revision surgery can be applied in the primary setting to address these issues, particularly in terms of acetabular reconstruction. The purpose of this paper is to review some of the common conditions associated with complex primary THA, identify the associated surgical challenges they present and discuss techniques to address them.
Protrusio acetabuli Protrusio acetabuli is a hip joint deformity in which the medial wall of the acetabulum projects into the pelvis, with associated medial displacement of the femoral head. The causes can be divided into primary idiopathic (Otto pelvis), which mainly affects women, and secondary causes such as Paget’s disease, osteomalacia, inflammatory arthritis, ankylosing spondylitis, sickle cell disease, Marfans syndrome and trauma to the medial wall of the acetabulum.3,4
Christopher J Brew MD FRCS (Tr & Orth) Consultant Orthopaedic Surgeon, Bradford Royal Infirmary, Bradford, West Yorkshire, UK. Conflict of interests: none declared.
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migration of the femoral head. The centre-edge angle is measured from a vertical line drawn through the centre of femoral head and a line subtended from the centre of the head to the lateral edge of the acetabular roof. Normal values for adults average 36 (range 20 e46 ) and an average of 30 in children (range 15 e40 ). Therefore a centre-edge angle of >40 is thought to be indicative of a deepened acetabulum.4,7 Surgical challenges of protrusio Difficult dislocation of the hip due to medial migration of femoral head. There is a risk of acetabular wall fracture if forced. Consideration should be given to cutting the femoral neck in-situ if difficulty in dislocation is encountered. If the posterior approach is utilized the sciatic nerve may be found much closer to the posterior aspect of the hip joint than usual. This must be taken into consideration during the approach to minimize risk of injury. Particular care must be taken if cutting the neck in-situ in this regard. Careful acetabular reaming to avoid further medialization and compromise of the often very thin medial wall. It is important to avoid converting a contained medial bone defect into an uncontained defect. Therefore reaming should concentrate more on the periphery of the acetabulum and if an uncemented component is used, the aim should be to obtain a peripheral rim fit. The contained medial bone defect can be filled with morcellized bone using established impaction bone grafting techniques (Figure 2). Any defect in the medial wall can be plugged with a disc of bone from the femoral head or a medial wall metal mesh to ensure the defect is fully contained prior to undertaking impaction grafting. This has the effect of placing the acetabular component in an anatomical position, restoring the correct centre of hip rotation thereby improving survival of the acetabular component.8 Avoid lengthening of the leg following restoration of the hip centre by performing a low neck cut, particularly if using uncemented implants, and consider using modular components with adequate range of offsets. Mullaji et al. reported excellent medium term results in 23 cases of protrusio in the younger patient (mean age 46 years) treated using autologous impaction bone grafting in combination with cementless porous coated hemispheric cups. At mean follow up of 4.2 years (2e10 years) satisfactory graft consolidation was seen in all cases.9 Good results were also reported using cemented cups with autologous impaction grafting of the acetabulum, with Rosenberg et al. reporting a 90% survival rate at 12 years in 36 THA’s carried out for protrusio.10 Thin slices of femoral head have also been used as autografts to build up the medial wall with no evidence of relapse of the protrusio at an average of 4 years following surgery in 61 THA’s.11 As an alternative to bone grafting in large defects, Blumenfeld et al. reported the use of the cup-in-cup technique. This involved implanting a large porous tantalum acetabular shell into the supportive medial host bone and then cementing another tanatalum shell inside this in the correct orientation to restore the correct centre of rotation of the hip.12
Figure 1 (a) Bilateral severely osteoarthritic hips associated with significant acetabular bone loss. (b) acetabular reconstruction using rim mesh with impaction bone grafting.
Clinical examination may reveal a positive Trendelenburg test due to the compromised lever arm of the hip abductors. In more severe cases fixed flexion deformities of the pelvis with a compensatory hyperlordosis of the lumbar spine are often present, with limitation of flexion and moreso abduction. In very severe cases intra pelvic swelling can be felt on abdominal, rectal or vaginal palpation. The limiting point of medial migration of the femoral head occurs when the greater trochanter abuts against the lateral aspect of the pelvis, preventing any further progression. Long standing protrusio can result in the development of secondary osteoarthritic changes, with symptoms warranting THA. Radiological diagnosis is made from an anteroposterior radiograph of the pelvis. Protrusio acetabuli is present if the medial acetabular line crosses the ilioischial line (Kholer’s Line) by > 3 mm in men and >6 mm in women. Friedenberg5 used the centre-edge angle, initially introduced by Wiberg,6 to assess acetabular development as a method to monitor medial
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The most common classification systems used are those described by Hartofilakidis et al.13e15 and Crowe et al.16 Hartofilakidis classification describes the position of the femoral head in relation to the true acetabulum: Type A e Mild dysplasia (femoral head in true acetabulum); Type B e Low dislocation (femoral head articulates with false acetabulum but overlaps with true acetabulum); Type C e High dislocation (femoral head completely dislocated and migrated superiorly, articulating only with false acetabulum). Crowe et al. described the extend of proximal migration of the femoral head as a proportion of the height of the undeformed femoral head: Type 1 e (<0.1); Type 2 e Type 3 e Type 4 e
50%e74% (0.1e0.15); 75%e100% (0.16e0.2); >100% (>0.2).
Crowe also described the degree of subluxation/dislocation by a second measurement derived by dividing the vertical distance between the tear drop and the headeneck junction of the femur by the vertical height of the pelvis taken from the ischial tuberosities to the top of the iliac crests (ratio shown in brackets). Both systems have been demonstrated to have satisfactory inter and intra observer reliability. However the Crowe classification is arguably more involved in determining the exact level of the headeneck junction, which can introduce variability, and also requires a whole pelvic radiograph (including iliac crests). For preoperative templating of the femora the radiograph needs to be centred on the symphysis pubis. The latter films therefore often truncate the iliac crests and specific films are needed for the classification (Figure 3a). The advantages of the Hartofilakidis classification is that it is easy to apply and gives an immediate indication of the anatomical challenges that will be encountered if THA is to be attempted, the Crowe classification providing a more quantitative assessment. There are many anatomic abnormalities that can present in the dysplastic hip, making preoperative planning absolutely essential in order to minimize the risk of complications. Features often encountered in the dysplastic hip include a small and deformed femoral head, often subluxed or dislocated. There may be the formation of a false acetabulum and it is vital that the presence of a false acetabulum is recognized preoperatively so that the true acetabulum can located at the time of surgery. The acetabular component should ideally be placed in the anatomic position, although some authors report acceptable outcomes with placement of a high but not lateral hip centre.17,18 The advantages of placing of a high hip centre are that it may be technically easier than defining the dysplastic true acetabulum intraoperatively and may reduce the need for bone grafting and acetabular augmentation, as well as utilizing living host bone. However, placement of a high hip centre has been shown to cause excessive shear stresses and increased component loosening, as well as increased dislocation rates.19 Correction of leg length discrepancy is also made more difficult if the normal hip centre is not restored.
Figure 2 Impaction bone autografting to medial wall of acetabulum in protrusio.
Short term follow up (average 28 months) revealed no loosening or migration of the components.
Adult hip dysplasia Developmental dysplasia of the hip (DDH) is the most common cause of secondary osteoarthritis in the UK and represents a significant caseload for the orthopaedic surgeon. The term ‘dysplasia’ is a broad term and implies abnormal development of the hip, which can affect all aspects of the hip on both the acetabular and femoral side to varying degrees. This can therefore present a number of significant surgical challenges when attempting to perform THA on these complex and often relative young patients. It is important that the surgeon is aware of the common deformities likely to be encountered in the dysplastic hip and is competent in the various reconstructive techniques on both the femoral and acetabular side before attempting reconstruction. The more severe the dysplasia, the more potential surgical reconstructive challenges the surgeon will be likely to face and therefore it is useful to classify the degree of dysplasia as part of the preoperative planning.
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Migrated <50% of the height of undeformed head
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can commence to medialize and recreate an acetabulum capable of accommodating the acetabular component. When reaming, more bone should be taken posteriorly in order to avoid perforation of the thin anterior wall. Due to the deficient anterior wall, care must also be taken not to place the cup in excessive anteversion in order to minimize the risk of anterior dislocation, particularly if increased femoral anteversion is not fully appreciated. Hartofilakides et al. have described a technique called cotyloplasty of creating a controlled fracture of the medial wall with autograft augmentation and the use of a small cemented cup in order to medialize the acetabular component sufficiently.15 The acetabular trial can then be introduced to assess coverage. In some cases there is deficient superolateral bony coverage resulting in the need for acetabular reconstruction using bone graft or trabecular metal augments. This type of acetabular defect is also seen in other complex primary cases, especially in aggressive forms of osteoarthritis and avascular necrosis. The reconstructive techniques discussed are applicable to all cases where a superolateral acetabular defect is encountered and not just cases of DDH.
Acetabular reconstruction Structural bone graft The success of THA in dysplastic hips is determined by how accurately the normal hip centre is restored and by stable fixation of the implants.20 Often, in dysplastic hips, the superolateral aspect of the acetabulum is deficient. When using a cementless cup for reconstruction it has been suggested that as long as there is adequate bony support from the anterior and posterior acetabular walls, up to 75e80% acetabular component bone coverage is adequate.21 However if there is a larger uncontained defect there are various acetabular reconstruction techniques that can be employed, depending on the nature of the defect and surgeon preference. Bulk femoral head autograft or allograft can been used to reconstruct the deficient acetabulum supero-laterally by fashioning a segment of femoral head much like a segment of orange (Figure 4) or shaping a graft in the form of a Figure 7 and placing it in an inverted position in the superolateral defect and fixing it
Figure 3 (a) Dysplastic right hip with high dislocation (Hartofilakidis Type C). First stage revision for infection left hip. (b) Right hip reconstruction with subtrochanteric osteotomy and acetabular rim mesh combined with impaction bone grafting. Left hip second stage reconstruction using a constrained cup.
During exposure the hip is dislocated from the false acetabulum. The true acetabulum is often not easily apparent, as the true acetabulum itself is often filled with soft tissue pulvinar. There is often a ledge of bone dividing the false from the true acetabulum and this must not be mistaken for the inferior edge of the true acetabulum in order to avoid a high hip centre, but can be used as a landmark for further inferior dissection. Key landmarks include identifying the transverse acetabular ligament, which marks the inferior border of the true acetabulum, which often appears shallow. It is usually filled with soft tissue and bone and can be oblong or triangular in nature with deficient bone supero-laterally in many cases. In order to recreate the normal centre of rotation of the hip it is important to find the true medial and inferior margins of the acetabulum. This is achieved by removing the curtain osteophyte and pulvinar from the cotyloid fossa to identify the true medial wall and by placing a retractor inferiorly, under the transverse acetabular ligament, thereby marking the correct level for accurate placement of the acetabular component. Once the landmarks of the true acetabulum have been identified reaming
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Figure 4 Acetabular reconstruction using bulk autograft.
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be less technically demanding than the placement of a large rim mesh. The augments are available in a range of diameters and thicknesses allowing virtually any size of defect to be accommodated (Figure 5).
to the ilium with partially threaded 4.5 mm cancellous screws. However, structural allografts have had unfavourable outcomes in the mid to long-term, with high rates of cup migration and graft failure when used with either cementless or cemented acetabular components. Hooten et al. reported 44% migration at a mean of 46 months.22 Shinar et al. reported the 16.5 year follow up of 70 hips treated with bulk structural bone graft (55 were autograft) predominantly in patients with DDH in combination with cemented cups. 36% had been revised for aseptic loosening and a further 26% had signs of loosening. The authors noted that the younger the patient, and the greater the extent of coverage of the acetabular component by graft, the higher the failure rate.23 However Hendrich et al. reported 91.6% survival rates at 11 years in 56 dysplastic hips treated with cementless cups and bulk bone grafting although this dropped to 88.9% with loosening as an end point.24 Good mid term results using femoral head bulk autograft and cementless cups in patients with DDH were also described by Schofer et al. with a 6.7% revision rate at a mean of 5.6 year follow up of 118 THA’s.25 Kim et al. reported a 94% survival rate of 83 THA’s at 10 years using similar techniques.26
Technique: careful acetabular reaming is used to assess the size of the defect and smooth off the host bone to fashion a congruent defect shape. An acetabular cup trial is then placed in the acetabulum in the correct anatomical orientation and the defect size and shape can be assessed and fashioned until it is suitably filled with the appropriate augment trial. Once the correct augment size and shape has been selected it is held in place with two or three 6.5 mm cancellous screws depending on the manufacturer. The acetabular trial is then re-inserted to ensure the correct cup orientation can be obtained without impingement on the trial. The metal augments can be shaped with the use of a burr and drilled through if necessary. It is important to remember to place the acetabular component in the anatomical position, which is not necessarily in the same orientation as the augment. Morsellised bone graft is impacted in any gaps between the augment and host bone and can be impacted over the augment if desired. The cement is then pressurized and the cup inserted in the usual way.
Impaction bone grafting with rim mesh Acetabular reconstruction using a stainless steel rim mesh fixed to the pelvis with 3.5 mm cortical screws at approximately 1 cm intervals around the rim of the superolateral acetabular defect acts to convert an uncontained defect into a contained one, thereby allowing the well established technique of impaction bone grafting to be utilized to restore bone stock.27,28 A cemented acetabular component can then be placed in an anatomic position (Figure 1b). Like the other acetabular reconstruction techniques described, this method can be used to reconstruct any acetabulum with similar superolateral bony defects, whether in severe osteoarthritis or as a result of revision surgery. However Somford et al. and Bolder et al. have described this method with considerable success in DDH with a 96% survivorship at 10 years in 28 THA’s and 27 THA’s respectively.20,29 In the longer term Busch et al. reported a survival rate of 73% at 20 years and 52% at 25 years with this technique in 42 hips in patients younger than 50 years old and conclude that although survivorship declines after 20 years, impaction grafting with a cemented cup provides a successful way to restore bone stock in these young patients.30 For both structural bone graft and impaction grafting techniques, the larger the defect with a large area of graft covering the acetabular component, the higher the risk of revision.23,31
Femoral osteotomy In high dislocations a femoral shortening osteotomy, possibly combined with some de-rotation to compensate for increased femoral neck anteversion, may be required. If the femur has to be translated more than 3 cm a shortening osteotomy may be required in order to facilitate reduction of the hip in the true acetabulum without placing undue tension on the sciatic nerve, which may result in a palsy if the amount of lengthening required is not appreciated.33 This can be planned for preoperatively at the templating stage, so that appropriate femoral implants and necessary equipment for plating the femur can be made available if the need is predicted. Subtrochanteric osteotomies have been described in many forms including transverse, double-chevron, step and Z osteotomies.34e40 By far the most common is a transverse osteotomy, which allows both shortening and correction of excessive anteversion by de-rotating the proximal femur. This technique has been used successfully with both press-fit uncemented femoral components36e39,41,42 and cemented stems.34,35 When used with a cemented stem the osteotomy is stabilized with a small fragment dynamic compression plate using unicortical screws (Figure 3b). Despite some concerns about nonunion due to interposition of cement in the osteotomy site, the nonunion rates described by Howie et al. and Charity et al. are low with one infected nonunion in 33 osteotomies and one nonunion in 18 osteotomies respectively.34,35
Porous metal acetabular augmentation The mixed outcomes with bone grafting large acetabular defects have led to the use of porous metal augments in combination with impaction bone grafting to prevent cement interposition between host bone and augment, as well as to fill any residual defects and promote bony ingrowth. This has been used with considerable success in the short term, with Borland et al. describing only one revision for augment breakage out of 24 patients at an average follow up of 5 years.32 This technique has the advantages of not requiring the ordering of large amounts of allograft bone, some of which can be wasted in fear of underestimating the amount needed, and can
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Technique: the acetabular component is placed first to restore the correct hip centre. The proximal femur is prepared to accept the femoral trial using rasps and a burr if necessary. The lateral aspect of the proximal femur is exposed, minimizing soft tissue stripping. A longitudinal line is marked using diathermy or methylene blue on the lateral femur at the level of the osteotomy. A transverse osteotomy is performed just distal to the lesser trochanter. The hip is reduced and with some traction applied to the distal femur and the amount of femoral overlap is assessed
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Figure 5 (a) Preoperative radiograph showing avascular necrosis of femoral head and acetabular bone loss with subsequent femoral shortening. (b) Templating confirms extent of superolateral acetabular defect. (c) Reconstruction using trabecular metal augmentation and impaction bone grafting.
is often age-dependent. The majority of displaced acetabular fractures are currently managed by open reduction and internal fixation, particularly in the young.44 However in selected cases total hip arthroplasty can be performed acutely. The indications for acute THA following acetabular fracture include intra articular comminution with full thickness loss of articular cartilage, acetabular and femoral head impaction involving over 40% of joint surface including the main weight bearing surface. This can be complex surgery and the surgeon should be familiar with extensile approaches and internal fixation techniques including cable fixation of the acetabulum45 as well as bone grafting techniques in order to gain stability and allow early mobilization following THA. McKinley et al. suggested that performing acute THA should be the treatment of choice in the elderly, as initial ORIF has been shown to adversely affect late THA by compromising the blood supply and the soft tissue envelope by the formation of often extensive scar formation and heterotopic ossification. There were more complications seen in patients who underwent initial ORIF, including higher infection and dislocation rates, lower prosthetic survival rates and worse functional outcome.46 Mears et al. in a series of 57 patients undergoing acute THA for displaced acetabular fracture followed for a mean of 8.1 years (2e12 years) described some subsidence in the early postoperative period but all cups subsequently stabilized and none were revised at the latest follow up. The authors therefore concluded in selected patients with fracture patterns that are unlikely to respond favourably to ORIF that acute THA is a favourable option.47
and marked on the distal femur. A second parallel cut is performed to excise the appropriate amount of femur. Any rotational deformity can be corrected and the position noted with reference to the original longitudinal mark. The osteotomy is then stabilized with a small fragment, six-hole dynamic compression plate using unicortical screws. This can be done with the trial stem insitu for added stability and to ensure appropriate screw length. The stem is cemented using third generation techniques. Any cement escape at the osteotomy site is allowed to prevent cement being forced into osteotomy site elsewhere and then cleared out before curing. Autologous bone chips can then be packed into osteotomy site if any small gaps are apparent. The patient is usually mobilized partial weight bearing for 6e8 weeks building up to full weight bearing at 3 months. Shortening of the femur is not always necessary but sometimes de-rotation of the proximal femur is needed for anteversion of over 40 . However the use of modern fully modular tapered stemmed uncemented prostheses that can accommodate very narrow femoral canals and permit rotation of the proximal component independently of the stem may avoid having to use a de-rotation osteotomy. The usefulness of these devices was noted by Silber et al., who reported sixteen out of nineteen patients required modular components due to variability in femoral size and shape.43
Fractures about the hip Acetabular fractures Acetabular fracture configurations vary greatly depending on the energy transferred and the quality of the underlying bone, which
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However THA is more usually performed late for secondary osteoarthritis after previous open reduction and internal fixation or after initial failed conservative treatment. Previous reports on late THA following initial open or closed treatment of acetabular fractures have shown less favourable results than when THA was performed for degenerative disease.48,49 However Bellabarba et al. compared the use of cementless cups in patients with post traumatic arthritis and those with non traumatic arthritis and concluded that the intermediate term clinical results were similar for both groups regardless of whether the fracture had been fixed or not.50 However THA after fracture was shown to be a longer procedure with greater blood loss, especially if previous ORIF had been performed, although bone deficiency was found to be less in this group.
infection, dislocation, intraoperative fracture, non-union and aseptic loosening.54e56 Therefore some of these complications may be minimized by the appropriate use of customized implants (Figure 6b and c).
Neuromuscular abnormalities Patients undergoing THA with neurological conditions can present all of the challenges discussed above in terms of abnormal anatomy, but in addition can further tax the surgeon in dealing with muscle spasticity, paresis, contractures and tremors which potentially combine to produce imbalanced muscle tone across the hip. These factors combine to increase the risk of dislocation and aseptic loosening. For these reasons THA is rarely performed in these patients due to their complexity and frequently associated medical morbidities. Neuromuscular patients include a range of underlying conditions such as cerebral palsy (CP), Parkinson’s disease, poliomyelitis, cerebrovascular accident and spinal injuries to mention a few. Painful hips affect approximately 25e75% of patients with CP due to an imbalance between strong hip flexors and adductors overpowering the weaker extensors and abductors. This results in contractures and bony abnormalities including excessive anteversion and valgus of the femoral neck, abnormal development of the acetabulum and secondary osteoarthritis. Resection arthroplasty has been described for end stage disease but good outcomes in terms of functional improvement and pain relief have been described with the use of THA.57e59 In patients with neurological disorders there is an increased risk of dislocation due to muscle imbalance across the hip. The use of constrained acetabular components and, more recently, dual-mobility cups in patients with spastic disorders has been used with considerable success.60 By way of contrast, in poliomyelitis there is flaccid paralysis of the muscles across the hip joint resulting in dysplasia, subluxation and contractures. Evidence on the place of arthroplasty is really limited to few case reports with mixed results. Interestingly a review of the Scottish National Arthroplasty register by Meek et al.61 showed patients undergoing THA who had had a cerebral vascular accident (CVA) had a lower dislocation rate than the control population and it was hypothesized this was due to lower mobility levels. Queally et al. hypothesize that there are broadly two groups of patients with neurological dysfunction. The first includes those suffering from Parkinson’s disease or CVA and, due to relative immobility and medical treatments, they consider the risk of dislocation to be relatively low in this group and they suggest the use of unconstrained implants. This is contrasted with the second group consisting of patients with CP, poliomyelitis and spinal injury who are more likely to sublux and dislocate and therefore they recommend the use of constrained implants in this group.59 In summary THA is rarely performed in patients with neurological conditions due to the complexity of the surgery and the high risk of complications. However, in selected patients and with the use of modular femoral implants combined when necessary with constrained acetabular components, adequate soft tissue releases and the involvement of a multidisciplinary team, the current literature supports the use of THA as a viable treatment option for this difficult group.
Femoral fractures Proximal femoral fractures are extremely common in the elderly population and present a considerable proportion of the trauma workload. They are also seen in the younger polytrauma patient, who may present years later with a malunion associated with the development of secondary degenerative changes in the hip (Figure 6a). Failure of fracture fixation and the development of secondary osteoarthritis is an indication for conversion to THA. This at first glance may appear to be a relatively straightforward prospect, but there are a few potential pitfalls that the surgeon must be aware of before embarking on such procedures. Careful assessment of any in-situ metalwork to ensure appropriate removal kit is available. Ensure any metalwork that is intended to be left in-situ will not interfere with implants eg when reaming the acetabulum. Judet views are required and three-dimensional imaging should obtained if there is any doubt. Detailed templating is essential to ensure there is no need for a corrective femoral osteotomy and to ensure that standard implants will suffice. Otherwise customized implants can be considered.51,52 Alternatively, for femoral deformity at the metaphyseal ediaphyseal level, a corrective osteotomy placed at the apex of the deformity and stabilized with a fully coated, modular long-stemmed implant can be performed.53,54 The femoral canal may be sclerotic and the entry point difficult to find due to distorted anatomy. Careful use of hand reamers and a power burr may be needed to develop the entry point. Consider the use of image guidance when reaming to minimize the risk of fracture and perforation in those with significant deformity. When converting a failed DHS/cannulated screw fixation consider dislocation of the hip prior to removal of any metalwork to minimize the risk of fracture occurring through stress risers left by empty screw holes. If a cemented stem is used, bone wax is useful to plug screw holes to reduce cement leakage into soft tissues and minimize the risk of thermal damage. If a posterior approach is used beware the sciatic nerve lying in dense scar tissue closely adherent to the posterior aspect of the hip, posing an increased risk of iatrogenic injury. Corrective femoral osteotomy performed concurrently with THA is associated with increased complication rates including
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Figure 6 (a) Osteoarthritic hip with acetabular protrusio combined with an ipsilateral proximal femoral malunion. (b) Insertion of custom made short cemented stem into proximal femoral fragment. (c) Comparison with standard length stem.
Conclusion
centre. Careful templating will help appreciate the possible need for modular or customized implants, ensuring their availability at the time of surgery, thereby maximizing the probability of a good outcome for the patient. A
Complex primary hip replacement can present a significant surgical challenge. An understanding of the varied underlying pathologies followed up with meticulous preoperative planning is required to overcome the intraoperative problems often encountered as a result of distorted anatomy and associated bone loss. The surgeon must be familiar with the use of reconstructive bone grafting techniques in order to restore the normal hip
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REFERENCES 1 9th National Joint Registy Annual report 2012.
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2 Sottish Arthroplasty Project Biennial report 2012. 3 Sathappan SS, Strauss EJ, Ginat D, Upasani V, Di Cesare PE. Surgical challenges in complex primary total hip arthroplasty. Am J Orthop (Belle Mead NJ) 2007 Oct; 36: 534e41. 4 Van de Velde S, Fillman R, Yandow S. Protrusio acetabuli in Marfan syndrome. History, diagnosis, and treatment. J Bone Joint Surg Am 2006 Mar; 88: 639e46. 5 Friedenberg ZB. Protrusio acetabuli in childhood. J Bone Joint Surg Am 1963; 45: 373e8. 6 Wiberg G. Studies on dysplastic acetabula and congenital subluxation of the hip joint. With special reference to the complication of osteoarthritis. Acta Chir Scand 1939; 83: 5e135. 7 McBride MT, Muldoon MP, Santore RF, Trousdale RT, Wenger DR. Protrusio acetabuli: diagnosis and treatment. J Am Acad Orthop Surg 2001 MareApr; 9: 79e88. 8 Bayley JC, Christie MJ, Ewald FC, Kelley K. Long-term results of total hip arthroplasty in protrusio acetabuli. J Arthroplasty 1987; 2: 275e9. 9 Mullaji AB, Marawar SV. Primary total hip arthroplasty in protrusio acetabuli using impacted morsellised bone grafting and cementless cups: a medium-term radiographic review. J Arthroplasty 2007 Dec; 22: 1143e9. 10 Rosenberg WW, Schreurs BW, de Waal Malefijt MC, Veth RP, Slooff TJ. Impacted morsellized bone grafting and cemented primary total hip arthroplasty for acetabular protrusion in patients with rheumatoid arthritis: an 8- to 18-year follow-up study of 36 hips. Acta Orthop Scand 2000 Apr; 71: 143e6. 11 Hirst P, Esser M, Murphy JC, Hardinge K. Bone grafting for protrusio acetabuli during total hip replacement. A review of the Wrightington method in 61 hips. J Bone Joint Surg Br 1987 Mar; 69: 229e33. 12 Blumenfeld TJ, Bargar WL. Surgical technique: a cup-in-cup technique to restore offset in severe protrusio acetabular defects. Clin Orthop Relat Res 2012 Feb; 470: 435e41. 13 Hartofilakidis G, Karachalios T. Idiopathic osteoarthritis of the hip: incidence, classification, and natural history of 272 cases. Orthopedics 2003 Feb; 26: 161e6. 14 Hartofilakidis G, Stamos K, Ioannidis TT. Low friction arthroplasty for old untreated congenital dislocation of the hip. J Bone Joint Surg Br 1988 Mar; 70: 182e6. 15 Hartofilakidis G, Stamos K, Karachalios T, Ioannidis TT, Zacharakis N. Congenital hip disease in adults. Classification of acetabular deficiencies and operative treatment with acetabuloplasty combined with total hip arthroplasty. J Bone Joint Surg Am 1996 May; 78: 683e92. 16 Crowe JF, Mani VJ, Ranawat CS. Total hip replacement in congenital dislocation and dysplasia of the hip. J Bone Joint Surg Am 1979 Jan; 61: 15e23. 17 Doehring TC, Rubash HE, Shelley FJ, Schwendeman LJ, Donaldson TK, Navalgund YA. Effect of superior and superolateral relocations of the hip center on hip joint forces. An experimental and analytical analysis. J Arthroplasty 1996 Sep; 11: 693e703. 18 Russotti GM, Harris WH. Proximal placement of the acetabular component in total hip arthroplasty. A long-term follow-up study. J Bone Joint Surg Am 1991 Apr; 73: 587e92. 19 Yoder SA, Brand RA, Pedersen DR, O’Gorman TW. Total hip acetabular component position affects component loosening rates. Clin Orthop Relat Res 1988 Mar; 79e87. 20 Bolder SB, Melenhorst J, Gardeniers JW, Slooff TJ, Veth RP, Schreurs BW. Cemented total hip arthroplasty with impacted morcellized bone-grafts to restore acetabular bone defects in congenital hip dysplasia. J Arthroplasty 2001 Dec; 16(8 suppl 1): 164e9.
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21 Rogers BA, Garbedian S, Kuchinad RA, Backstein D, Safir O, Gross AE. Total hip arthroplasty for adult hip dysplasia. J Bone Joint Surg Am 2012 Oct 3; 94: 1809e21. 22 Hooten Jr JP, Engh Jr CA, Engh CA. Failure of structural acetabular allografts in cementless revision hip arthroplasty. J Bone Joint Surg Br 1994 May; 76: 419e22. 23 Shinar AA, Harris WH. Bulk structural autogenous grafts and allografts for reconstruction of the acetabulum in total hip arthroplasty. Sixteen-year-average follow-up. J Bone Joint Surg Am 1997 Feb; 79: 159e68. 24 Hendrich C, Engelmaier F, Mehling I, Sauer U, Kirschner S, Martell JM. Cementless acetabular reconstruction and structural bone-grafting in dysplastic hips. Surgical technique. J Bone Joint Surg Am 2007 Mar; 89(suppl 2 Pt.1): 54e67. 25 Schofer MD, Pressel T, Schmitt J, Heyse TJ, Boudriot U. Reconstruction of the acetabulum in THA using femoral head autografts in developmental dysplasia of the hip. J Orthop Surg Res 2011; 6: 32. 26 Kim M, Kadowaki T. High long-term survival of bulk femoral head autograft for acetabular reconstruction in cementless THA for developmental hip dysplasia. Clin Orthop Relat Res 2010 Jun; 468: 1611e20. 27 Schreurs BW, Bolder SB, Gardeniers JW, Verdonschot N, Slooff TJ, Veth RP. Acetabular revision with impacted morsellised cancellous bone grafting and a cemented cup. A 15- to 20-year follow-up. J Bone Joint Surg Br 2004 May; 86: 492e7. 28 Schreurs BW, Busch VJ, Welten ML, Verdonschot N, Slooff TJ, Gardeniers JW. Acetabular reconstruction with impaction bonegrafting and a cemented cup in patients younger than fifty years old. J Bone Joint Surg Am 2004 Nov; 86-A: 2385e92. 29 Somford MP, Bolder SB, Gardeniers JW, Slooff TJ, Schreurs BW. Favorable survival of acetabular reconstruction with bone impaction grafting in dysplastic hips. Clin Orthop Relat Res 2008 Feb; 466: 359e65. 30 Busch VJ, Gardeniers JW, Verdonschot N, Slooff TJ, Schreurs BW. Acetabular reconstruction with impaction bone-grafting and a cemented cup in patients younger than fifty years old: a concise follow-up, at twenty to twenty-eight years, of a previous report. J Bone Joint Surg Am 2011 Feb 16; 93: 367e71. 31 Rigby M, Kenny PJ, Sharp R, Whitehouse SL, Gie GA, Timperley JA. Acetabular impaction grafting in total hip replacement. Hip Int 2011 Jul-Aug; 21: 399e408. 32 Borland WS, Bhattacharya R, Holland JP, Brewster NT. Use of porous trabecular metal augments with impaction bone grafting in management of acetabular bone loss. Acta Orthop 2012 Aug; 83: 347e52. 33 Garvin KL, Bowen MK, Salvati EA, Ranawat CS. Long-term results of total hip arthroplasty in congenital dislocation and dysplasia of the hip. A follow-up note. J Bone Joint Surg Am 1991 Oct; 73: 1348e54. 34 Charity JA, Tsiridis E, Sheeraz A, et al. Treatment of Crowe IV high hip dysplasia with total hip replacement using the Exeter stem and shortening derotational subtrochanteric osteotomy. J Bone Joint Surg Br 2011 Jan; 93: 34e8. 35 Howie CR, Ohly NE, Miller B. Cemented total hip arthroplasty with subtrochanteric osteotomy in dysplastic hips. Clin Orthop Relat Res 2010 Dec; 468: 3240e7. 36 Yasgur DJ, Stuchin SA, Adler EM, DiCesare PE. Subtrochanteric femoral shortening osteotomy in total hip arthroplasty for high-riding developmental dislocation of the hip. J Arthroplasty 1997 Dec; 12: 880e8. 37 Reikeraas O, Lereim P, Gabor I, Gunderson R, Bjerkreim I. Femoral shortening in total arthroplasty for completely dislocated hips: 3e7 year results in 25 cases. Acta Orthop Scand 1996 Feb; 67: 33e6.
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49 Berry DJ. Total hip arthroplasty following acetabular fracture. Orthopedics 1999 Sep; 22: 837e9. 50 Bellabarba C, Berger RA, Bentley CD, et al. Cementless acetabular reconstruction after acetabular fracture. J Bone Joint Surg Am 2001 Jun; 83-A: 868e76. 51 Benum P, Aamodt A. Uncemented custom femoral components in hip arthroplasty. A prospective clinical study of 191 hips followed for at least 7 years. Acta Orthop 2010 Aug; 81: 427e35. 52 Koulouvaris P, Stafylas K, Sculco T, Xenakis T. Custom-design implants for severe distorted proximal anatomy of the femur in young adults followed for 4-8 years. Acta Orthop 2008 Apr; 79: 203e10. 53 Mortazavi SM, Restrepo C, Kim PJ, Parvizi J, Hozack WJ. Cementless femoral reconstruction in patients with proximal femoral deformity. J Arthroplasty 2011 Apr; 26: 354e9. 54 Papagelopoulos PJ, Trousdale RT, Lewallen DG. Total hip arthroplasty with femoral osteotomy for proximal femoral deformity. Clin Orthop Relat Res 1996 Nov; 151e62. 55 Huo MH, Zatorski LE, Keggi KJ. Oblique femoral osteotomy in cementless total hip arthroplasty. Prospective consecutive series with a 3-year minimum follow-up period. J Arthroplasty 1995 Jun; 10: 319e27. 56 Peters CL, Beck M, Dunn HK. Total hip arthroplasty in young adults after failed triple innominate osteotomy. J Arthroplasty 2001 Feb; 16: 188e95. 57 Buly RL, Huo M, Root L, Binzer T, Wilson Jr PD. Total hip arthroplasty in cerebral palsy. Long-term follow-up results. Clin Orthop Relat Res 1993 Nov; 148e53. 58 Weber M, Cabanela ME. Total hip arthroplasty in patients with cerebral palsy. Orthopedics 1999 Apr; 22: 425e7. 59 Queally JM, Abdulkarim A, Mulhall KJ. Total hip replacement in patients with neurological conditions. J Bone Joint Surg Br 2009 Oct; 91: 1267e73. 60 Sanders RJ, Swierstra BA, Goosen JH. The use of a dual-mobility concept in total hip arthroplasty patients with spastic disorders: no dislocations in a series of ten cases at midterm follow-up. Arch Orthop Trauma Surg 2013 Jul; 133: 1011e6. 61 Meek RM, Allan DB, McPhillips G, Kerr L, Howie CR. Epidemiology of dislocation after total hip arthroplasty. Clin Orthop Relat Res 2006 Jun; 447: 9e18.
38 Paavilainen T, Hoikka V, Solonen KA. Cementless total replacement for severely dysplastic or dislocated hips. J Bone Joint Surg Br 1990 Mar; 72: 205e11. 39 Becker DA, Gustilo RB. Double-chevron subtrochanteric shortening derotational femoral osteotomy combined with total hip arthroplasty for the treatment of complete congenital dislocation of the hip in the adult. Preliminary report and description of a new surgical technique. J Arthroplasty 1995 Jun; 10: 313e8. 40 Semenowicz J, Szymanski S, Walo R, Czuma P, Pijet B. Total hip arthroplasty with shortening subtrochanteric Z osteotomy in the treatment of developmental dysplasia with high hip dislocation. Ortop Traumatol Rehabil 2012 Jul-Aug; 14: 341e9. 41 Bruce WJ, Rizkallah SM, Kwon YM, Goldberg JA, Walsh WR. A new technique of subtrochanteric shortening in total hip arthroplasty: surgical technique and results of 9 cases. J Arthroplasty 2000 Aug; 15: 617e26. 42 Krych AJ, Howard JL, Trousdale RT, Cabanela ME, Berry DJ. Total hip arthroplasty with shortening subtrochanteric osteotomy in Crowe type-IV developmental dysplasia. J Bone Joint Surg Am 2009 Sep; 91: 2213e21. 43 Silber DA, Engh CA. Cementless total hip arthroplasty with femoral head bone grafting for hip dysplasia. J Arthroplasty 1990 Sep; 5: 231e40. 44 Matta JM. Fractures of the acetabulum: accuracy of reduction and clinical results in patients managed operatively within three weeks after the injury. J Bone Joint Surg Am 1996 Nov; 78: 1632e45. 45 Mouhsine E, Garofalo R, Borens O, et al. Acute total hip arthroplasty for acetabular fractures in the elderly: 11 patients followed for 2 years. Acta Orthop Scand 2002 Dec; 73: 615e8. 46 McKinley JC, Robinson CM. Treatment of displaced intracapsular hip fractures with total hip arthroplasty: comparison of primary arthroplasty with early salvage arthroplasty after failed internal fixation. J Bone Joint Surg Am 2002 Nov; 84-A: 2010e5. 47 Mears DC, Velyvis JH. Acute total hip arthroplasty for selected displaced acetabular fractures: two to twelve-year results. J Bone Joint Surg Am 2002 Jan; 84-A: 1e9. 48 Romness DW, Lewallen DG. Total hip arthroplasty after fracture of the acetabulum. Long-term results. J Bone Joint Surg Br 1990 Sep; 72: 761e4.
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(iii) Surgical tactics in the difficult primary hip replacement
Conditions associated with complex primary total hip arthroplasty either as a result of the primary pathology or in combination with previous treatments Developmental dysplasia Perthes Slipped upper femoral epiphysis Avascular necrosis Severe primary osteoarthritis Aggressive rheumatoid arthritis Protrusio acetabuli Neuromuscular conditions Fractures about the hip Skeletal dysplasias Septic arthritis Paget’s disease
Christopher J Brew
Abstract The term complex primary total hip arthroplasty (THA) is used when THA is performed on patients with any combination of abnormal anatomy, bone loss and compromised soft tissues. This is often as a result of the development of secondary osteoarthritis complicating an underlying primary pathology. Those most commonly associated are developmental hip dysplasia, protrusio acetabuli, skeletal dysplasias, previous fractures or surgical procedures about the hip and neuromuscular conditions, but this is by no means an exhaustive list. The importance of preoperative planning and the use of reconstructive techniques including bone grafting, as well as the use of modular and customized implants to overcome these significant surgical challenges, are discussed.
Table 1
Preoperative assessment The indications for surgery include uncontrolled pain with functional impairment and radiographic evidence of secondary degenerative change. Contraindications include the presence of infection and a surgically unfit patient. A detailed history should be taken including any known diagnosis of childhood hip problems and any previous operations on the hips. A standard examination of the hip should be performed, paying particular attention to true and apparent leg length discrepancy, which can often be significant, Thomas’s test for fixed flexion deformity, range of motion and any neuromuscular abnormality should be carefully assessed. In the primary setting a significant recent leg length change that is noticed by the patient should alert the surgeon to severe progressive bone loss and ensure an up to date radiograph is available. A plain anteroposterior (AP) radiograph of the pelvis centred on the symphysis with a marker ball for templating should be obtained (Figure 1a). Depending on the underlying pathology a true lateral radiograph can be useful to assess for abnormal bone alignment of the proximal femur, which is often present after previous corrective osteotomies. Furthermore it can be used to assess for increased femoral neck anteversion, as may regularly be seen with dysplastic hips. Computed Tomography (CT) can be utilized in cases of significantly altered anatomy and is useful for estimating the size of bony defects, the integrity of the anterior and posterior columns and any deficiencies in the walls of the acetabulum, thereby informing detailed planning for reconstruction.
Keywords acetabular reconstruction; complex primary total hip arthroplasty; femoral osteotomy; impaction bone grafting; structural bone graft
Introduction Primary total hip arthroplasty (THA) is one of the most successful and rewarding operations performed, with approximately 77 000 carried out every year in the United Kingdom.1,2 The vast majority of these procedures are carried out for primary osteoarthritis, but a smaller proportion of primary cases are performed to treat secondary osteoarthritis resulting from other underlying pathologies. (Table 1). The very nature of these pathologies means that the surgeon can be faced with performing a hip replacement on a patient with any combination of compromised bone stock, abnormal primary or secondary anatomy as a result of previous treatments and compromised soft tissue states. Such procedures are therefore termed complex primary THA and can present significant surgical challenges. Often some of the principles and techniques used in revision surgery can be applied in the primary setting to address these issues, particularly in terms of acetabular reconstruction. The purpose of this paper is to review some of the common conditions associated with complex primary THA, identify the associated surgical challenges they present and discuss techniques to address them.
Protrusio acetabuli Protrusio acetabuli is a hip joint deformity in which the medial wall of the acetabulum projects into the pelvis, with associated medial displacement of the femoral head. The causes can be divided into primary idiopathic (Otto pelvis), which mainly affects women, and secondary causes such as Paget’s disease, osteomalacia, inflammatory arthritis, ankylosing spondylitis, sickle cell disease, Marfans syndrome and trauma to the medial wall of the acetabulum.3,4
Christopher J Brew MD FRCS (Tr & Orth) Consultant Orthopaedic Surgeon, Bradford Royal Infirmary, Bradford, West Yorkshire, UK. Conflict of interests: none declared.
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migration of the femoral head. The centre-edge angle is measured from a vertical line drawn through the centre of femoral head and a line subtended from the centre of the head to the lateral edge of the acetabular roof. Normal values for adults average 36 (range 20 e46 ) and an average of 30 in children (range 15 e40 ). Therefore a centre-edge angle of >40 is thought to be indicative of a deepened acetabulum.4,7 Surgical challenges of protrusio Difficult dislocation of the hip due to medial migration of femoral head. There is a risk of acetabular wall fracture if forced. Consideration should be given to cutting the femoral neck in-situ if difficulty in dislocation is encountered. If the posterior approach is utilized the sciatic nerve may be found much closer to the posterior aspect of the hip joint than usual. This must be taken into consideration during the approach to minimize risk of injury. Particular care must be taken if cutting the neck in-situ in this regard. Careful acetabular reaming to avoid further medialization and compromise of the often very thin medial wall. It is important to avoid converting a contained medial bone defect into an uncontained defect. Therefore reaming should concentrate more on the periphery of the acetabulum and if an uncemented component is used, the aim should be to obtain a peripheral rim fit. The contained medial bone defect can be filled with morcellized bone using established impaction bone grafting techniques (Figure 2). Any defect in the medial wall can be plugged with a disc of bone from the femoral head or a medial wall metal mesh to ensure the defect is fully contained prior to undertaking impaction grafting. This has the effect of placing the acetabular component in an anatomical position, restoring the correct centre of hip rotation thereby improving survival of the acetabular component.8 Avoid lengthening of the leg following restoration of the hip centre by performing a low neck cut, particularly if using uncemented implants, and consider using modular components with adequate range of offsets. Mullaji et al. reported excellent medium term results in 23 cases of protrusio in the younger patient (mean age 46 years) treated using autologous impaction bone grafting in combination with cementless porous coated hemispheric cups. At mean follow up of 4.2 years (2e10 years) satisfactory graft consolidation was seen in all cases.9 Good results were also reported using cemented cups with autologous impaction grafting of the acetabulum, with Rosenberg et al. reporting a 90% survival rate at 12 years in 36 THA’s carried out for protrusio.10 Thin slices of femoral head have also been used as autografts to build up the medial wall with no evidence of relapse of the protrusio at an average of 4 years following surgery in 61 THA’s.11 As an alternative to bone grafting in large defects, Blumenfeld et al. reported the use of the cup-in-cup technique. This involved implanting a large porous tantalum acetabular shell into the supportive medial host bone and then cementing another tanatalum shell inside this in the correct orientation to restore the correct centre of rotation of the hip.12
Figure 1 (a) Bilateral severely osteoarthritic hips associated with significant acetabular bone loss. (b) acetabular reconstruction using rim mesh with impaction bone grafting.
Clinical examination may reveal a positive Trendelenburg test due to the compromised lever arm of the hip abductors. In more severe cases fixed flexion deformities of the pelvis with a compensatory hyperlordosis of the lumbar spine are often present, with limitation of flexion and moreso abduction. In very severe cases intra pelvic swelling can be felt on abdominal, rectal or vaginal palpation. The limiting point of medial migration of the femoral head occurs when the greater trochanter abuts against the lateral aspect of the pelvis, preventing any further progression. Long standing protrusio can result in the development of secondary osteoarthritic changes, with symptoms warranting THA. Radiological diagnosis is made from an anteroposterior radiograph of the pelvis. Protrusio acetabuli is present if the medial acetabular line crosses the ilioischial line (Kholer’s Line) by > 3 mm in men and >6 mm in women. Friedenberg5 used the centre-edge angle, initially introduced by Wiberg,6 to assess acetabular development as a method to monitor medial
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The most common classification systems used are those described by Hartofilakidis et al.13e15 and Crowe et al.16 Hartofilakidis classification describes the position of the femoral head in relation to the true acetabulum: Type A e Mild dysplasia (femoral head in true acetabulum); Type B e Low dislocation (femoral head articulates with false acetabulum but overlaps with true acetabulum); Type C e High dislocation (femoral head completely dislocated and migrated superiorly, articulating only with false acetabulum). Crowe et al. described the extend of proximal migration of the femoral head as a proportion of the height of the undeformed femoral head: Type 1 e (<0.1); Type 2 e Type 3 e Type 4 e
50%e74% (0.1e0.15); 75%e100% (0.16e0.2); >100% (>0.2).
Crowe also described the degree of subluxation/dislocation by a second measurement derived by dividing the vertical distance between the tear drop and the headeneck junction of the femur by the vertical height of the pelvis taken from the ischial tuberosities to the top of the iliac crests (ratio shown in brackets). Both systems have been demonstrated to have satisfactory inter and intra observer reliability. However the Crowe classification is arguably more involved in determining the exact level of the headeneck junction, which can introduce variability, and also requires a whole pelvic radiograph (including iliac crests). For preoperative templating of the femora the radiograph needs to be centred on the symphysis pubis. The latter films therefore often truncate the iliac crests and specific films are needed for the classification (Figure 3a). The advantages of the Hartofilakidis classification is that it is easy to apply and gives an immediate indication of the anatomical challenges that will be encountered if THA is to be attempted, the Crowe classification providing a more quantitative assessment. There are many anatomic abnormalities that can present in the dysplastic hip, making preoperative planning absolutely essential in order to minimize the risk of complications. Features often encountered in the dysplastic hip include a small and deformed femoral head, often subluxed or dislocated. There may be the formation of a false acetabulum and it is vital that the presence of a false acetabulum is recognized preoperatively so that the true acetabulum can located at the time of surgery. The acetabular component should ideally be placed in the anatomic position, although some authors report acceptable outcomes with placement of a high but not lateral hip centre.17,18 The advantages of placing of a high hip centre are that it may be technically easier than defining the dysplastic true acetabulum intraoperatively and may reduce the need for bone grafting and acetabular augmentation, as well as utilizing living host bone. However, placement of a high hip centre has been shown to cause excessive shear stresses and increased component loosening, as well as increased dislocation rates.19 Correction of leg length discrepancy is also made more difficult if the normal hip centre is not restored.
Figure 2 Impaction bone autografting to medial wall of acetabulum in protrusio.
Short term follow up (average 28 months) revealed no loosening or migration of the components.
Adult hip dysplasia Developmental dysplasia of the hip (DDH) is the most common cause of secondary osteoarthritis in the UK and represents a significant caseload for the orthopaedic surgeon. The term ‘dysplasia’ is a broad term and implies abnormal development of the hip, which can affect all aspects of the hip on both the acetabular and femoral side to varying degrees. This can therefore present a number of significant surgical challenges when attempting to perform THA on these complex and often relative young patients. It is important that the surgeon is aware of the common deformities likely to be encountered in the dysplastic hip and is competent in the various reconstructive techniques on both the femoral and acetabular side before attempting reconstruction. The more severe the dysplasia, the more potential surgical reconstructive challenges the surgeon will be likely to face and therefore it is useful to classify the degree of dysplasia as part of the preoperative planning.
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Migrated <50% of the height of undeformed head
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can commence to medialize and recreate an acetabulum capable of accommodating the acetabular component. When reaming, more bone should be taken posteriorly in order to avoid perforation of the thin anterior wall. Due to the deficient anterior wall, care must also be taken not to place the cup in excessive anteversion in order to minimize the risk of anterior dislocation, particularly if increased femoral anteversion is not fully appreciated. Hartofilakides et al. have described a technique called cotyloplasty of creating a controlled fracture of the medial wall with autograft augmentation and the use of a small cemented cup in order to medialize the acetabular component sufficiently.15 The acetabular trial can then be introduced to assess coverage. In some cases there is deficient superolateral bony coverage resulting in the need for acetabular reconstruction using bone graft or trabecular metal augments. This type of acetabular defect is also seen in other complex primary cases, especially in aggressive forms of osteoarthritis and avascular necrosis. The reconstructive techniques discussed are applicable to all cases where a superolateral acetabular defect is encountered and not just cases of DDH.
Acetabular reconstruction Structural bone graft The success of THA in dysplastic hips is determined by how accurately the normal hip centre is restored and by stable fixation of the implants.20 Often, in dysplastic hips, the superolateral aspect of the acetabulum is deficient. When using a cementless cup for reconstruction it has been suggested that as long as there is adequate bony support from the anterior and posterior acetabular walls, up to 75e80% acetabular component bone coverage is adequate.21 However if there is a larger uncontained defect there are various acetabular reconstruction techniques that can be employed, depending on the nature of the defect and surgeon preference. Bulk femoral head autograft or allograft can been used to reconstruct the deficient acetabulum supero-laterally by fashioning a segment of femoral head much like a segment of orange (Figure 4) or shaping a graft in the form of a Figure 7 and placing it in an inverted position in the superolateral defect and fixing it
Figure 3 (a) Dysplastic right hip with high dislocation (Hartofilakidis Type C). First stage revision for infection left hip. (b) Right hip reconstruction with subtrochanteric osteotomy and acetabular rim mesh combined with impaction bone grafting. Left hip second stage reconstruction using a constrained cup.
During exposure the hip is dislocated from the false acetabulum. The true acetabulum is often not easily apparent, as the true acetabulum itself is often filled with soft tissue pulvinar. There is often a ledge of bone dividing the false from the true acetabulum and this must not be mistaken for the inferior edge of the true acetabulum in order to avoid a high hip centre, but can be used as a landmark for further inferior dissection. Key landmarks include identifying the transverse acetabular ligament, which marks the inferior border of the true acetabulum, which often appears shallow. It is usually filled with soft tissue and bone and can be oblong or triangular in nature with deficient bone supero-laterally in many cases. In order to recreate the normal centre of rotation of the hip it is important to find the true medial and inferior margins of the acetabulum. This is achieved by removing the curtain osteophyte and pulvinar from the cotyloid fossa to identify the true medial wall and by placing a retractor inferiorly, under the transverse acetabular ligament, thereby marking the correct level for accurate placement of the acetabular component. Once the landmarks of the true acetabulum have been identified reaming
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Figure 4 Acetabular reconstruction using bulk autograft.
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be less technically demanding than the placement of a large rim mesh. The augments are available in a range of diameters and thicknesses allowing virtually any size of defect to be accommodated (Figure 5).
to the ilium with partially threaded 4.5 mm cancellous screws. However, structural allografts have had unfavourable outcomes in the mid to long-term, with high rates of cup migration and graft failure when used with either cementless or cemented acetabular components. Hooten et al. reported 44% migration at a mean of 46 months.22 Shinar et al. reported the 16.5 year follow up of 70 hips treated with bulk structural bone graft (55 were autograft) predominantly in patients with DDH in combination with cemented cups. 36% had been revised for aseptic loosening and a further 26% had signs of loosening. The authors noted that the younger the patient, and the greater the extent of coverage of the acetabular component by graft, the higher the failure rate.23 However Hendrich et al. reported 91.6% survival rates at 11 years in 56 dysplastic hips treated with cementless cups and bulk bone grafting although this dropped to 88.9% with loosening as an end point.24 Good mid term results using femoral head bulk autograft and cementless cups in patients with DDH were also described by Schofer et al. with a 6.7% revision rate at a mean of 5.6 year follow up of 118 THA’s.25 Kim et al. reported a 94% survival rate of 83 THA’s at 10 years using similar techniques.26
Technique: careful acetabular reaming is used to assess the size of the defect and smooth off the host bone to fashion a congruent defect shape. An acetabular cup trial is then placed in the acetabulum in the correct anatomical orientation and the defect size and shape can be assessed and fashioned until it is suitably filled with the appropriate augment trial. Once the correct augment size and shape has been selected it is held in place with two or three 6.5 mm cancellous screws depending on the manufacturer. The acetabular trial is then re-inserted to ensure the correct cup orientation can be obtained without impingement on the trial. The metal augments can be shaped with the use of a burr and drilled through if necessary. It is important to remember to place the acetabular component in the anatomical position, which is not necessarily in the same orientation as the augment. Morsellised bone graft is impacted in any gaps between the augment and host bone and can be impacted over the augment if desired. The cement is then pressurized and the cup inserted in the usual way.
Impaction bone grafting with rim mesh Acetabular reconstruction using a stainless steel rim mesh fixed to the pelvis with 3.5 mm cortical screws at approximately 1 cm intervals around the rim of the superolateral acetabular defect acts to convert an uncontained defect into a contained one, thereby allowing the well established technique of impaction bone grafting to be utilized to restore bone stock.27,28 A cemented acetabular component can then be placed in an anatomic position (Figure 1b). Like the other acetabular reconstruction techniques described, this method can be used to reconstruct any acetabulum with similar superolateral bony defects, whether in severe osteoarthritis or as a result of revision surgery. However Somford et al. and Bolder et al. have described this method with considerable success in DDH with a 96% survivorship at 10 years in 28 THA’s and 27 THA’s respectively.20,29 In the longer term Busch et al. reported a survival rate of 73% at 20 years and 52% at 25 years with this technique in 42 hips in patients younger than 50 years old and conclude that although survivorship declines after 20 years, impaction grafting with a cemented cup provides a successful way to restore bone stock in these young patients.30 For both structural bone graft and impaction grafting techniques, the larger the defect with a large area of graft covering the acetabular component, the higher the risk of revision.23,31
Femoral osteotomy In high dislocations a femoral shortening osteotomy, possibly combined with some de-rotation to compensate for increased femoral neck anteversion, may be required. If the femur has to be translated more than 3 cm a shortening osteotomy may be required in order to facilitate reduction of the hip in the true acetabulum without placing undue tension on the sciatic nerve, which may result in a palsy if the amount of lengthening required is not appreciated.33 This can be planned for preoperatively at the templating stage, so that appropriate femoral implants and necessary equipment for plating the femur can be made available if the need is predicted. Subtrochanteric osteotomies have been described in many forms including transverse, double-chevron, step and Z osteotomies.34e40 By far the most common is a transverse osteotomy, which allows both shortening and correction of excessive anteversion by de-rotating the proximal femur. This technique has been used successfully with both press-fit uncemented femoral components36e39,41,42 and cemented stems.34,35 When used with a cemented stem the osteotomy is stabilized with a small fragment dynamic compression plate using unicortical screws (Figure 3b). Despite some concerns about nonunion due to interposition of cement in the osteotomy site, the nonunion rates described by Howie et al. and Charity et al. are low with one infected nonunion in 33 osteotomies and one nonunion in 18 osteotomies respectively.34,35
Porous metal acetabular augmentation The mixed outcomes with bone grafting large acetabular defects have led to the use of porous metal augments in combination with impaction bone grafting to prevent cement interposition between host bone and augment, as well as to fill any residual defects and promote bony ingrowth. This has been used with considerable success in the short term, with Borland et al. describing only one revision for augment breakage out of 24 patients at an average follow up of 5 years.32 This technique has the advantages of not requiring the ordering of large amounts of allograft bone, some of which can be wasted in fear of underestimating the amount needed, and can
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Technique: the acetabular component is placed first to restore the correct hip centre. The proximal femur is prepared to accept the femoral trial using rasps and a burr if necessary. The lateral aspect of the proximal femur is exposed, minimizing soft tissue stripping. A longitudinal line is marked using diathermy or methylene blue on the lateral femur at the level of the osteotomy. A transverse osteotomy is performed just distal to the lesser trochanter. The hip is reduced and with some traction applied to the distal femur and the amount of femoral overlap is assessed
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Figure 5 (a) Preoperative radiograph showing avascular necrosis of femoral head and acetabular bone loss with subsequent femoral shortening. (b) Templating confirms extent of superolateral acetabular defect. (c) Reconstruction using trabecular metal augmentation and impaction bone grafting.
is often age-dependent. The majority of displaced acetabular fractures are currently managed by open reduction and internal fixation, particularly in the young.44 However in selected cases total hip arthroplasty can be performed acutely. The indications for acute THA following acetabular fracture include intra articular comminution with full thickness loss of articular cartilage, acetabular and femoral head impaction involving over 40% of joint surface including the main weight bearing surface. This can be complex surgery and the surgeon should be familiar with extensile approaches and internal fixation techniques including cable fixation of the acetabulum45 as well as bone grafting techniques in order to gain stability and allow early mobilization following THA. McKinley et al. suggested that performing acute THA should be the treatment of choice in the elderly, as initial ORIF has been shown to adversely affect late THA by compromising the blood supply and the soft tissue envelope by the formation of often extensive scar formation and heterotopic ossification. There were more complications seen in patients who underwent initial ORIF, including higher infection and dislocation rates, lower prosthetic survival rates and worse functional outcome.46 Mears et al. in a series of 57 patients undergoing acute THA for displaced acetabular fracture followed for a mean of 8.1 years (2e12 years) described some subsidence in the early postoperative period but all cups subsequently stabilized and none were revised at the latest follow up. The authors therefore concluded in selected patients with fracture patterns that are unlikely to respond favourably to ORIF that acute THA is a favourable option.47
and marked on the distal femur. A second parallel cut is performed to excise the appropriate amount of femur. Any rotational deformity can be corrected and the position noted with reference to the original longitudinal mark. The osteotomy is then stabilized with a small fragment, six-hole dynamic compression plate using unicortical screws. This can be done with the trial stem insitu for added stability and to ensure appropriate screw length. The stem is cemented using third generation techniques. Any cement escape at the osteotomy site is allowed to prevent cement being forced into osteotomy site elsewhere and then cleared out before curing. Autologous bone chips can then be packed into osteotomy site if any small gaps are apparent. The patient is usually mobilized partial weight bearing for 6e8 weeks building up to full weight bearing at 3 months. Shortening of the femur is not always necessary but sometimes de-rotation of the proximal femur is needed for anteversion of over 40 . However the use of modern fully modular tapered stemmed uncemented prostheses that can accommodate very narrow femoral canals and permit rotation of the proximal component independently of the stem may avoid having to use a de-rotation osteotomy. The usefulness of these devices was noted by Silber et al., who reported sixteen out of nineteen patients required modular components due to variability in femoral size and shape.43
Fractures about the hip Acetabular fractures Acetabular fracture configurations vary greatly depending on the energy transferred and the quality of the underlying bone, which
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However THA is more usually performed late for secondary osteoarthritis after previous open reduction and internal fixation or after initial failed conservative treatment. Previous reports on late THA following initial open or closed treatment of acetabular fractures have shown less favourable results than when THA was performed for degenerative disease.48,49 However Bellabarba et al. compared the use of cementless cups in patients with post traumatic arthritis and those with non traumatic arthritis and concluded that the intermediate term clinical results were similar for both groups regardless of whether the fracture had been fixed or not.50 However THA after fracture was shown to be a longer procedure with greater blood loss, especially if previous ORIF had been performed, although bone deficiency was found to be less in this group.
infection, dislocation, intraoperative fracture, non-union and aseptic loosening.54e56 Therefore some of these complications may be minimized by the appropriate use of customized implants (Figure 6b and c).
Neuromuscular abnormalities Patients undergoing THA with neurological conditions can present all of the challenges discussed above in terms of abnormal anatomy, but in addition can further tax the surgeon in dealing with muscle spasticity, paresis, contractures and tremors which potentially combine to produce imbalanced muscle tone across the hip. These factors combine to increase the risk of dislocation and aseptic loosening. For these reasons THA is rarely performed in these patients due to their complexity and frequently associated medical morbidities. Neuromuscular patients include a range of underlying conditions such as cerebral palsy (CP), Parkinson’s disease, poliomyelitis, cerebrovascular accident and spinal injuries to mention a few. Painful hips affect approximately 25e75% of patients with CP due to an imbalance between strong hip flexors and adductors overpowering the weaker extensors and abductors. This results in contractures and bony abnormalities including excessive anteversion and valgus of the femoral neck, abnormal development of the acetabulum and secondary osteoarthritis. Resection arthroplasty has been described for end stage disease but good outcomes in terms of functional improvement and pain relief have been described with the use of THA.57e59 In patients with neurological disorders there is an increased risk of dislocation due to muscle imbalance across the hip. The use of constrained acetabular components and, more recently, dual-mobility cups in patients with spastic disorders has been used with considerable success.60 By way of contrast, in poliomyelitis there is flaccid paralysis of the muscles across the hip joint resulting in dysplasia, subluxation and contractures. Evidence on the place of arthroplasty is really limited to few case reports with mixed results. Interestingly a review of the Scottish National Arthroplasty register by Meek et al.61 showed patients undergoing THA who had had a cerebral vascular accident (CVA) had a lower dislocation rate than the control population and it was hypothesized this was due to lower mobility levels. Queally et al. hypothesize that there are broadly two groups of patients with neurological dysfunction. The first includes those suffering from Parkinson’s disease or CVA and, due to relative immobility and medical treatments, they consider the risk of dislocation to be relatively low in this group and they suggest the use of unconstrained implants. This is contrasted with the second group consisting of patients with CP, poliomyelitis and spinal injury who are more likely to sublux and dislocate and therefore they recommend the use of constrained implants in this group.59 In summary THA is rarely performed in patients with neurological conditions due to the complexity of the surgery and the high risk of complications. However, in selected patients and with the use of modular femoral implants combined when necessary with constrained acetabular components, adequate soft tissue releases and the involvement of a multidisciplinary team, the current literature supports the use of THA as a viable treatment option for this difficult group.
Femoral fractures Proximal femoral fractures are extremely common in the elderly population and present a considerable proportion of the trauma workload. They are also seen in the younger polytrauma patient, who may present years later with a malunion associated with the development of secondary degenerative changes in the hip (Figure 6a). Failure of fracture fixation and the development of secondary osteoarthritis is an indication for conversion to THA. This at first glance may appear to be a relatively straightforward prospect, but there are a few potential pitfalls that the surgeon must be aware of before embarking on such procedures. Careful assessment of any in-situ metalwork to ensure appropriate removal kit is available. Ensure any metalwork that is intended to be left in-situ will not interfere with implants eg when reaming the acetabulum. Judet views are required and three-dimensional imaging should obtained if there is any doubt. Detailed templating is essential to ensure there is no need for a corrective femoral osteotomy and to ensure that standard implants will suffice. Otherwise customized implants can be considered.51,52 Alternatively, for femoral deformity at the metaphyseal ediaphyseal level, a corrective osteotomy placed at the apex of the deformity and stabilized with a fully coated, modular long-stemmed implant can be performed.53,54 The femoral canal may be sclerotic and the entry point difficult to find due to distorted anatomy. Careful use of hand reamers and a power burr may be needed to develop the entry point. Consider the use of image guidance when reaming to minimize the risk of fracture and perforation in those with significant deformity. When converting a failed DHS/cannulated screw fixation consider dislocation of the hip prior to removal of any metalwork to minimize the risk of fracture occurring through stress risers left by empty screw holes. If a cemented stem is used, bone wax is useful to plug screw holes to reduce cement leakage into soft tissues and minimize the risk of thermal damage. If a posterior approach is used beware the sciatic nerve lying in dense scar tissue closely adherent to the posterior aspect of the hip, posing an increased risk of iatrogenic injury. Corrective femoral osteotomy performed concurrently with THA is associated with increased complication rates including
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Figure 6 (a) Osteoarthritic hip with acetabular protrusio combined with an ipsilateral proximal femoral malunion. (b) Insertion of custom made short cemented stem into proximal femoral fragment. (c) Comparison with standard length stem.
Conclusion
centre. Careful templating will help appreciate the possible need for modular or customized implants, ensuring their availability at the time of surgery, thereby maximizing the probability of a good outcome for the patient. A
Complex primary hip replacement can present a significant surgical challenge. An understanding of the varied underlying pathologies followed up with meticulous preoperative planning is required to overcome the intraoperative problems often encountered as a result of distorted anatomy and associated bone loss. The surgeon must be familiar with the use of reconstructive bone grafting techniques in order to restore the normal hip
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REFERENCES 1 9th National Joint Registy Annual report 2012.
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2 Sottish Arthroplasty Project Biennial report 2012. 3 Sathappan SS, Strauss EJ, Ginat D, Upasani V, Di Cesare PE. Surgical challenges in complex primary total hip arthroplasty. Am J Orthop (Belle Mead NJ) 2007 Oct; 36: 534e41. 4 Van de Velde S, Fillman R, Yandow S. Protrusio acetabuli in Marfan syndrome. History, diagnosis, and treatment. J Bone Joint Surg Am 2006 Mar; 88: 639e46. 5 Friedenberg ZB. Protrusio acetabuli in childhood. J Bone Joint Surg Am 1963; 45: 373e8. 6 Wiberg G. Studies on dysplastic acetabula and congenital subluxation of the hip joint. With special reference to the complication of osteoarthritis. Acta Chir Scand 1939; 83: 5e135. 7 McBride MT, Muldoon MP, Santore RF, Trousdale RT, Wenger DR. Protrusio acetabuli: diagnosis and treatment. J Am Acad Orthop Surg 2001 MareApr; 9: 79e88. 8 Bayley JC, Christie MJ, Ewald FC, Kelley K. Long-term results of total hip arthroplasty in protrusio acetabuli. J Arthroplasty 1987; 2: 275e9. 9 Mullaji AB, Marawar SV. Primary total hip arthroplasty in protrusio acetabuli using impacted morsellised bone grafting and cementless cups: a medium-term radiographic review. J Arthroplasty 2007 Dec; 22: 1143e9. 10 Rosenberg WW, Schreurs BW, de Waal Malefijt MC, Veth RP, Slooff TJ. Impacted morsellized bone grafting and cemented primary total hip arthroplasty for acetabular protrusion in patients with rheumatoid arthritis: an 8- to 18-year follow-up study of 36 hips. Acta Orthop Scand 2000 Apr; 71: 143e6. 11 Hirst P, Esser M, Murphy JC, Hardinge K. Bone grafting for protrusio acetabuli during total hip replacement. A review of the Wrightington method in 61 hips. J Bone Joint Surg Br 1987 Mar; 69: 229e33. 12 Blumenfeld TJ, Bargar WL. Surgical technique: a cup-in-cup technique to restore offset in severe protrusio acetabular defects. Clin Orthop Relat Res 2012 Feb; 470: 435e41. 13 Hartofilakidis G, Karachalios T. Idiopathic osteoarthritis of the hip: incidence, classification, and natural history of 272 cases. Orthopedics 2003 Feb; 26: 161e6. 14 Hartofilakidis G, Stamos K, Ioannidis TT. Low friction arthroplasty for old untreated congenital dislocation of the hip. J Bone Joint Surg Br 1988 Mar; 70: 182e6. 15 Hartofilakidis G, Stamos K, Karachalios T, Ioannidis TT, Zacharakis N. Congenital hip disease in adults. Classification of acetabular deficiencies and operative treatment with acetabuloplasty combined with total hip arthroplasty. J Bone Joint Surg Am 1996 May; 78: 683e92. 16 Crowe JF, Mani VJ, Ranawat CS. Total hip replacement in congenital dislocation and dysplasia of the hip. J Bone Joint Surg Am 1979 Jan; 61: 15e23. 17 Doehring TC, Rubash HE, Shelley FJ, Schwendeman LJ, Donaldson TK, Navalgund YA. Effect of superior and superolateral relocations of the hip center on hip joint forces. An experimental and analytical analysis. J Arthroplasty 1996 Sep; 11: 693e703. 18 Russotti GM, Harris WH. Proximal placement of the acetabular component in total hip arthroplasty. A long-term follow-up study. J Bone Joint Surg Am 1991 Apr; 73: 587e92. 19 Yoder SA, Brand RA, Pedersen DR, O’Gorman TW. Total hip acetabular component position affects component loosening rates. Clin Orthop Relat Res 1988 Mar; 79e87. 20 Bolder SB, Melenhorst J, Gardeniers JW, Slooff TJ, Veth RP, Schreurs BW. Cemented total hip arthroplasty with impacted morcellized bone-grafts to restore acetabular bone defects in congenital hip dysplasia. J Arthroplasty 2001 Dec; 16(8 suppl 1): 164e9.
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21 Rogers BA, Garbedian S, Kuchinad RA, Backstein D, Safir O, Gross AE. Total hip arthroplasty for adult hip dysplasia. J Bone Joint Surg Am 2012 Oct 3; 94: 1809e21. 22 Hooten Jr JP, Engh Jr CA, Engh CA. Failure of structural acetabular allografts in cementless revision hip arthroplasty. J Bone Joint Surg Br 1994 May; 76: 419e22. 23 Shinar AA, Harris WH. Bulk structural autogenous grafts and allografts for reconstruction of the acetabulum in total hip arthroplasty. Sixteen-year-average follow-up. J Bone Joint Surg Am 1997 Feb; 79: 159e68. 24 Hendrich C, Engelmaier F, Mehling I, Sauer U, Kirschner S, Martell JM. Cementless acetabular reconstruction and structural bone-grafting in dysplastic hips. Surgical technique. J Bone Joint Surg Am 2007 Mar; 89(suppl 2 Pt.1): 54e67. 25 Schofer MD, Pressel T, Schmitt J, Heyse TJ, Boudriot U. Reconstruction of the acetabulum in THA using femoral head autografts in developmental dysplasia of the hip. J Orthop Surg Res 2011; 6: 32. 26 Kim M, Kadowaki T. High long-term survival of bulk femoral head autograft for acetabular reconstruction in cementless THA for developmental hip dysplasia. Clin Orthop Relat Res 2010 Jun; 468: 1611e20. 27 Schreurs BW, Bolder SB, Gardeniers JW, Verdonschot N, Slooff TJ, Veth RP. Acetabular revision with impacted morsellised cancellous bone grafting and a cemented cup. A 15- to 20-year follow-up. J Bone Joint Surg Br 2004 May; 86: 492e7. 28 Schreurs BW, Busch VJ, Welten ML, Verdonschot N, Slooff TJ, Gardeniers JW. Acetabular reconstruction with impaction bonegrafting and a cemented cup in patients younger than fifty years old. J Bone Joint Surg Am 2004 Nov; 86-A: 2385e92. 29 Somford MP, Bolder SB, Gardeniers JW, Slooff TJ, Schreurs BW. Favorable survival of acetabular reconstruction with bone impaction grafting in dysplastic hips. Clin Orthop Relat Res 2008 Feb; 466: 359e65. 30 Busch VJ, Gardeniers JW, Verdonschot N, Slooff TJ, Schreurs BW. Acetabular reconstruction with impaction bone-grafting and a cemented cup in patients younger than fifty years old: a concise follow-up, at twenty to twenty-eight years, of a previous report. J Bone Joint Surg Am 2011 Feb 16; 93: 367e71. 31 Rigby M, Kenny PJ, Sharp R, Whitehouse SL, Gie GA, Timperley JA. Acetabular impaction grafting in total hip replacement. Hip Int 2011 Jul-Aug; 21: 399e408. 32 Borland WS, Bhattacharya R, Holland JP, Brewster NT. Use of porous trabecular metal augments with impaction bone grafting in management of acetabular bone loss. Acta Orthop 2012 Aug; 83: 347e52. 33 Garvin KL, Bowen MK, Salvati EA, Ranawat CS. Long-term results of total hip arthroplasty in congenital dislocation and dysplasia of the hip. A follow-up note. J Bone Joint Surg Am 1991 Oct; 73: 1348e54. 34 Charity JA, Tsiridis E, Sheeraz A, et al. Treatment of Crowe IV high hip dysplasia with total hip replacement using the Exeter stem and shortening derotational subtrochanteric osteotomy. J Bone Joint Surg Br 2011 Jan; 93: 34e8. 35 Howie CR, Ohly NE, Miller B. Cemented total hip arthroplasty with subtrochanteric osteotomy in dysplastic hips. Clin Orthop Relat Res 2010 Dec; 468: 3240e7. 36 Yasgur DJ, Stuchin SA, Adler EM, DiCesare PE. Subtrochanteric femoral shortening osteotomy in total hip arthroplasty for high-riding developmental dislocation of the hip. J Arthroplasty 1997 Dec; 12: 880e8. 37 Reikeraas O, Lereim P, Gabor I, Gunderson R, Bjerkreim I. Femoral shortening in total arthroplasty for completely dislocated hips: 3e7 year results in 25 cases. Acta Orthop Scand 1996 Feb; 67: 33e6.
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Ó 2013 Elsevier Ltd. All rights reserved.
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49 Berry DJ. Total hip arthroplasty following acetabular fracture. Orthopedics 1999 Sep; 22: 837e9. 50 Bellabarba C, Berger RA, Bentley CD, et al. Cementless acetabular reconstruction after acetabular fracture. J Bone Joint Surg Am 2001 Jun; 83-A: 868e76. 51 Benum P, Aamodt A. Uncemented custom femoral components in hip arthroplasty. A prospective clinical study of 191 hips followed for at least 7 years. Acta Orthop 2010 Aug; 81: 427e35. 52 Koulouvaris P, Stafylas K, Sculco T, Xenakis T. Custom-design implants for severe distorted proximal anatomy of the femur in young adults followed for 4-8 years. Acta Orthop 2008 Apr; 79: 203e10. 53 Mortazavi SM, Restrepo C, Kim PJ, Parvizi J, Hozack WJ. Cementless femoral reconstruction in patients with proximal femoral deformity. J Arthroplasty 2011 Apr; 26: 354e9. 54 Papagelopoulos PJ, Trousdale RT, Lewallen DG. Total hip arthroplasty with femoral osteotomy for proximal femoral deformity. Clin Orthop Relat Res 1996 Nov; 151e62. 55 Huo MH, Zatorski LE, Keggi KJ. Oblique femoral osteotomy in cementless total hip arthroplasty. Prospective consecutive series with a 3-year minimum follow-up period. J Arthroplasty 1995 Jun; 10: 319e27. 56 Peters CL, Beck M, Dunn HK. Total hip arthroplasty in young adults after failed triple innominate osteotomy. J Arthroplasty 2001 Feb; 16: 188e95. 57 Buly RL, Huo M, Root L, Binzer T, Wilson Jr PD. Total hip arthroplasty in cerebral palsy. Long-term follow-up results. Clin Orthop Relat Res 1993 Nov; 148e53. 58 Weber M, Cabanela ME. Total hip arthroplasty in patients with cerebral palsy. Orthopedics 1999 Apr; 22: 425e7. 59 Queally JM, Abdulkarim A, Mulhall KJ. Total hip replacement in patients with neurological conditions. J Bone Joint Surg Br 2009 Oct; 91: 1267e73. 60 Sanders RJ, Swierstra BA, Goosen JH. The use of a dual-mobility concept in total hip arthroplasty patients with spastic disorders: no dislocations in a series of ten cases at midterm follow-up. Arch Orthop Trauma Surg 2013 Jul; 133: 1011e6. 61 Meek RM, Allan DB, McPhillips G, Kerr L, Howie CR. Epidemiology of dislocation after total hip arthroplasty. Clin Orthop Relat Res 2006 Jun; 447: 9e18.
38 Paavilainen T, Hoikka V, Solonen KA. Cementless total replacement for severely dysplastic or dislocated hips. J Bone Joint Surg Br 1990 Mar; 72: 205e11. 39 Becker DA, Gustilo RB. Double-chevron subtrochanteric shortening derotational femoral osteotomy combined with total hip arthroplasty for the treatment of complete congenital dislocation of the hip in the adult. Preliminary report and description of a new surgical technique. J Arthroplasty 1995 Jun; 10: 313e8. 40 Semenowicz J, Szymanski S, Walo R, Czuma P, Pijet B. Total hip arthroplasty with shortening subtrochanteric Z osteotomy in the treatment of developmental dysplasia with high hip dislocation. Ortop Traumatol Rehabil 2012 Jul-Aug; 14: 341e9. 41 Bruce WJ, Rizkallah SM, Kwon YM, Goldberg JA, Walsh WR. A new technique of subtrochanteric shortening in total hip arthroplasty: surgical technique and results of 9 cases. J Arthroplasty 2000 Aug; 15: 617e26. 42 Krych AJ, Howard JL, Trousdale RT, Cabanela ME, Berry DJ. Total hip arthroplasty with shortening subtrochanteric osteotomy in Crowe type-IV developmental dysplasia. J Bone Joint Surg Am 2009 Sep; 91: 2213e21. 43 Silber DA, Engh CA. Cementless total hip arthroplasty with femoral head bone grafting for hip dysplasia. J Arthroplasty 1990 Sep; 5: 231e40. 44 Matta JM. Fractures of the acetabulum: accuracy of reduction and clinical results in patients managed operatively within three weeks after the injury. J Bone Joint Surg Am 1996 Nov; 78: 1632e45. 45 Mouhsine E, Garofalo R, Borens O, et al. Acute total hip arthroplasty for acetabular fractures in the elderly: 11 patients followed for 2 years. Acta Orthop Scand 2002 Dec; 73: 615e8. 46 McKinley JC, Robinson CM. Treatment of displaced intracapsular hip fractures with total hip arthroplasty: comparison of primary arthroplasty with early salvage arthroplasty after failed internal fixation. J Bone Joint Surg Am 2002 Nov; 84-A: 2010e5. 47 Mears DC, Velyvis JH. Acute total hip arthroplasty for selected displaced acetabular fractures: two to twelve-year results. J Bone Joint Surg Am 2002 Jan; 84-A: 1e9. 48 Romness DW, Lewallen DG. Total hip arthroplasty after fracture of the acetabulum. Long-term results. J Bone Joint Surg Br 1990 Sep; 72: 761e4.
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