Introduction. Different classification systems for acetabular deficiencies, including AAOS and Paprosky, are commonly used. Classification of these bone defects is often performed based on Xrays or CT images. Although the amount of bone loss is rarely measured quantitatively in these images, objective and quantitative data on the degree of bone loss could facilitate correct and consistent classification. Recently, a computerized CT-based tool was presented to quantitatively asses bone loss: TrABL (Total radial Acetabular Bone Loss). This study demonstrates on an extended patient population that TrABL combined with standard classification systems provides more detailed, quantitative information on bone defects. Methods. CT scans of 30 severe acetabular defects, classified Paprosky IIIA and IIIB, were collected and analysed with TrABL. The tool automatically calculated the total amount of bone that was missing around the acetabulum, seen from the hip's original rotation centre. Six anatomical regions were defined for which the degree of bone loss was expressed: anterosuperior, anteroinferior, inferior, posteroinferior, posterosuperior and medial. Results. Statistical analysis highlighted that total bone loss was highest in the posterosuperior region (63%±27%). Bone loss was lowest inferiorly. No statistical differences were found between the anterosuperior, anteroinferior, posteroinferior, and medial regions. The majority of the defects suffered at least 25% bone loss in more than half of the regions. All defects had at least one region with the same degree of bone loss. The quantitative 3D data of TrABL provided more information compared to general classification schemes. This information has shown to be crucial during implant selection and preoperative planning for multiple clinical cases. Conclusion. Classification of acetabular bone deficiencies into existing systems can be refined by the quantitative data provided by TrABL. As a result, the ease and consistency regarding the treatment selection for particular categories of challenging defects will increase

Acetabular cages are necessary when an uncemented or cemented cup cannot be stabilised at the correct anatomic level. Impaction grafting with mesh for containment of bone graft is an alternative for some cases in centers that specialise in this technique.

At our center we use three types of cage constructs –

(A) Conventional cage ± structural or morselised bone grafting. This construct is used where there is no significant bleeding host bone. This construct is susceptible to cage fatigue and fracture. This reconstruction is used in young patients where restoration of bone stock is important.

(B) Conventional cage in combination with a porous augment where contact with bleeding host bone can be with the ilium and then by the use of cement that construct can be unified. The augment provides contact with bleeding host bone and if and when ingrowth occurs, the stress is taken off the cage.

(C) Cup Cage Construct – in this construct there must be enough bleeding host bone to stabilise the ultra-porous cup which functions like a structural allograft supporting and eventually taking the stress off the cage. This construct is ideal for pelvic discontinuity with the ultra-porous cup, i.e., bridging and to some degree distracting the discontinuity. If, however, the ultra-porous cup cannot be stabilised against some bleeding host bone, then a conventional stand-alone cage must be used.

In our center the cup cage reconstruction is our most common technique where a cage is used, especially if there is a pelvic discontinuity.

Acetabular bone loss and presence of pelvic discontinuity were assessed according to the Gross classification. Sixty-seven cup-cage procedures with an average follow-up of 74 months (range, 24–135 months; SD, 34.3) months were identified; 26 of 67 (39%) were Gross Type IV and 41 of 67 (61%) were Gross Type V (pelvic discontinuity). Failure was defined as revision surgery for any cause, including infection.

The 5-year Kaplan-Meier survival rate with revision for any cause representing failure was 93% (95% confidence interval, 83.1–97.4), and the 10-year survival rate was 85% (95% CI, 67.2–93.8). The Merle d'Aubigné-Postel score improved significantly from a mean of 6 pre-operatively to 13 post-operatively (p < 0.001). Four cup-cage constructs had non-progressive radiological migration of the ischial flange and they remain stable.

Reconstruction of an acetabulum following severe bone loss can be challenging. The aim of this study was to determine the outcome of acetabular reconstruction performed using trabecular metal shell for severe bone loss.

Between June 2003 and June 2006 a total of 29 patients with significant acetabular bone stock deficiency underwent revisions using trabacular metal shell. According to Paprosky classification, there were 18 patients with grade IIIA and 11 patients with grade IIIB defects. Nineteen patients required augments to supplement the defects. Functional clinical outcomes were measured by WOMAC and Oxford hip. Detailed radiological assessments were also made.

At most recent follow up (average 5.5 years, range 3.5–8.5) the mean Oxford hip score improved from 12 preoperatively to 27.11 postoperatively and WOMAC score from 17.57 preoperatively to 34.14 postoperatively The osseointegration was 83% according to Moore's classification. There were two reoperations; one was for instability, and one for aseptic loosening. One patient has a chronic infection and one had a periprosthetic fracture, both treated conservatively.

Despite challenges faced with severe preoperative acetabular defects the early results using this technique in Grade III A and B is encouraging.

Aim. Aim of this monocentric, prospective study was to evaluate the safety, efficacy, clinical and radiographical results at 24-month follow-up (N = 6 patients) undergoing hip revision surgery with severe acetabular bone defects (Paprosky 2C-3A-3B) using a combination of a novel phase-pure betatricalciumphosphate - collagen 3D matrix with allograft bone chips. Method. Prospective follow-up of 6 consecutive patients, who underwent revision surgery of the acetabular component in presence of massive bone defects between April 2018 and July 2019. Indications for revision included mechanical loosening in 4 cases and history of hip infection in 2 cases. Acetabular deficiencies were evaluated radiographically and CT and classified according to the Paprosky classification. Initial diagnosis of the patients included osteoarthritis (N = 4), a traumatic fracture and a congenital hip dislocation. 5 patients underwent first revision surgery, 1 patient underwent a second revision surgery. Results. All patients were followed-up radiographically with a mean of 25,8 months. No complications were observed direct postoperatively. HHS improved significantly from 23.9 preoperatively to 81.5 at the last follow-up. 5 patients achieved a defined good result, and one patient achieved a fair result. No periprosthetic joint infection, no dislocations, no deep vein thrombosis, no vessel damage, and no complaint about limbs length discrepancy could be observed. Postoperative dysmetria was found to be + 0.2cm (0cm/+1.0cm) compared to the preoperative dysmetria of − 2.4 cm (+0.3cm/−5.7cm). Conclusions. Although used in severe acetabular bone defects, the novel phase-pure betatricalciumphosphate - collagen 3D matrixshowed complete resorption and replacement by newly formed bone, leading to a full implant integration at 24 months follow-up and thus represents a promising method with excellent bone regeneration capacities for complex cases, where synthetic bone grafting material is used in addition to autografts

Introduction. Total hip arthroplasties in younger patients often requires revision because these patients frequently have acetabular deficiencies, which hamper proper implantation of the cup essential for good long-term prosthesis survival. For 30 years, we have used a biological acetabular-reconstruction technique with bone-impaction grafting in all patients <50 years with an acetabular deficiency at surgery, always in combination with a cemented total hip implant. Methods. We evaluated all 150 consecutive patients (177 hips) < 50 years with an acetabular reconstruction by bone-impaction grafting surgically-treated from 1978–2004 at our clinic. Mean follow-up was 10.3 (range, 2.0–28.3) years with no patient lost to follow-up. Mean index surgery age was 38.1 (range, 16–49) years. Clinical, radiological, and statistical analysis of all patients was performed. Results. Twenty-eight of 177 hips were revised at a mean of 10.5 years (range, 5 days to 23.2 years). Reasons for revision were: aseptic loosening (n=17), septic loosening (n=3), recurrent dislocations (n=3), traumatic loosening (n=2), neuropathy (n=1), wear (n=1), and fracture (n=1). Ten-year and 15-year survival with endpoint revision of any component for any reason was 91% and 78%. Ten-year survival with endpoint aseptic loosening was 96% for the cup and 97% for the stem. Conclusion. Performing a total hip implant in combination with acetabular bone impaction grafting in younger patients with acetabular bone stock loss seems to be an attractive approach as the long-term results are acceptable and fulfill the NICE-criteria, showing a ten -year survival of more than 90% with endpoint revisions for any reason

Developmental dysplasia of the hip (DDH) represents a heterogeneous group of deformities that are commonly associated with secondary osteoarthritis. Affected hips may require total hip arthroplasty (THA) for endstage disease and these cases can present unique challenges for the reconstructive surgeon. While the severity of deformity varies greatly, optimizing THA can be challenging even in the “mildly” dysplastic hip. These disorders are commonly characterised by acetabular deficiency with inadequate coverage of the anterolateral femoral head and proximal femoral abnormalities including excessive femoral antetorsion, coxa valga and femoral stenosis. In more severe cases, major femoral head subluxation or dislocation can add additional complexity to the procedure. In addition to the primary deformities of DDH, secondary deformities from previous acetabular or proximal femoral osteotomies may also impact the primary THA. Primary THA in the DDH hip can be optimised by detailed understanding of the bony anatomy, careful pre-operative planning, and an appropriate spectrum of techniques and implants for the given case. This presentation will review the abnormal hip morphologies encountered in the dysplastic hip and will focus on the more challenging aspects of THA. These include acetabular reconstruction of the severely deficient socket and in the setting of total dislocation, femoral implant procedures combined with corrective osteotomy or shortening, and issues related to arthroplasty in the setting of previous pelvic osteotomy. Despite the complexity of reconstruction for various dysplastic variants the clinical outcomes and survivorship of these procedures are good to excellent for most patients. Nevertheless, more complex procedures are associated with an increased complication rate and this should be considered in the surgical decision-making process

Acetabular impaction grafting (AIG) for the reconstruction of acetabular defects in total hip arthroplasty has the potential to recreate anatomy whilst also allowing the restoration of bone stock. The incorporation of impacted, morcellised bone graft has been demonstrated in histological studies and is a well established technique in revision hip surgery where there is loss of bone stock. We have studied our results of fullAIG when used in primary total hip arthroplasty, with particular emphasis on the results of AIG in cavitary and segmental defects. Between 1995 and 2003, 129 cemented primary THAs were performed using full acetabular impaction grafting to reconstruct acetabular deficiencies. These were classified as cavitary in 74 and segmental in 55 hips. Eighty-one patients were reviewed at mean 9.1 (6.2–14.3) years post-operatively. There were seven acetabular component revisions due to aseptic loosening, and a further 11 cases that had migrated »5 mm or tilted »5° on radiological review — ten of which reported no symptoms. Kaplan–Meier analysis of revisions for aseptic loosening demonstrates 100% survival at nine years for cavitary defects compared to 82.6% for segmental defects. Our results suggest that the medium-term survival of this technique is excellent when used for purely cavitary defects but less predictable when used with large rim meshes in segmental defects

Introduction. Impaction bone grafting for reconstitution of acetabular bone stock in revision hip surgery has been used for nearly 30 years. We report results in a group of patients upon whom data has been collected prospectively with a minimum ten year follow-up. Material and Methods. Acetabular impaction grafting was performed in 305 hips in 293 patients revised for aseptic loosening between 1995 and 2001. In this series 33% of cases required stainless steel meshes to reconstruct medial wall or rim defects prior to graft impaction. These meshes were the the only implants used for this purpose in this series. All Paprosky grades of defect were included. Clinical and radiographic outcomes were collected in surviving patients at a minimum of 10 years following the index operation; mean follow-up was 12.4 years (SD 1.5; range 10.0–16.0). Results. Kaplan-Meier survivorship with revision for aseptic loosening as the endpoint was 86% (95% CI 81.1 to 90.9%). Clinical scores for pain relief and function remained satisfactory (mean OHS 33.3, Harris hip score for pain 36.7, Harris hip score for function 27.3). Of the 125 hips still available with at least 10 years of radiographic follow-up, 97 appeared stable and 28 were judged to be radiologically loose; however, there was no significant difference in the pain and function scores between the two groups. The overall complication rate was 11.5%, including 1% peri-operative death, 3.3% dislocation and 0.3% deep infection. Discussion. This is the largest series of medium- to long-term results of acetabular impaction bone grafting with a cemented cup for revision hip arthroplasty reported to date. The technique is particularly successful when used for Paprosky grade 1 and 2 deficiencies; grade 3 deficiencies may be better managed with a different method for reconstructing larger defects e.g. trabecular metal augments. Conclusion. This series shows good long-term results for impaction bone grafting of acetabular deficiencies in revision hip surgery, with survivorship of 86% for aseptic loosening at 13.5 years and satisfactory clinical outcomes

Major bone loss involving the acetabulum can be seen during revision THA due to component loosening, migration or osteolysis and can also occur as a sequela of infected THA. Uncemented porous ingrowth components can be used for reconstruction of the vast majority of revision cases, where smaller segmental or cavitary defects are typically present. But when stable structural support on host bone is lacking, highly porous metal acetabular augments have been described as an alternative to large structural allograft, avoiding the potential for later graft resorption and the resulting loss of mechanical support that can follow. The fundamental concept behind these acetabular augments is the provision of critical additional fixation, structural support and increased contact area against host bone over the weeks following surgery while the desired ingrowth into porous implant surfaces is occurring. Technique: Three separate patterns of augment placement have been utilised in our practice since the development of these implants: Type 1 - augment screwed onto the superolateral acetabular rim in a “flying buttress” configuration for treatment of a segmental rim defect, Type 2 – augment placed superiorly against host and then fixed (with cement) to the acetabular component adjacent to the cup to fill a mainly elliptical cavitary defect, and Type 3 – augment(s) placed medial to the cup to fill a protrusio type cavitary or combined cavitary segmental defect of the superomedial or medial wall, and allow peripheral cup placement against the still intact acetabular rim. In all cases the acetabular component and augment interface is fixed together with cement, with care to prevent any cement extrusion between any implant and the bone. When possible, we now prefer to place the acetabular component first and fix it provisionally with 2 or more screws, and then place the augments second as this is technically quicker and easier. This order of insertion is only possible though in type 1 and a few select type 2 cases. Type 3 cases always require placement of one or more augments first, before cup insertion. Supplemental cancellous bone graft is used routinely. Results: From 2000 through 2007, porous tantalum acetabular augments were used very selectively in 85 revision THA procedures out of total of 1,789 revision hip cases performed at our institution in that time frame. All cases had associated massive acetabular deficiency precluding stable mechanical support for a cup alone. Fifty-eight hips had complete radiographic as well as clinical follow at minimum 5 years. The majority of patients had either Paprosky type 3A defects (28/58, 48%) or 3B defects (22/58, 38%). Ten out of 58 had pre-operative pelvic discontinuities. At 5 years, 2/58 (3%) were revised for aseptic loosening and another 6/58 demonstrated incomplete radiolucencies between the acetabular shell and zone 3. One of the revised cups and 5 of 6 of the cups with radiolucencies had an associated pelvic discontinuity. Summary: Highly porous metal acetabular augments are an infrequently needed, but extremely valuable, versatile and reliable adjunctive fixation method for use with uncemented acetabular components during complex revision THA associated with major bone deficiency. Intermediate term durability and apparent radiographic incorporation has been very good despite the complex reconstructions originally required. This technique can allow the avoidance of structural bone grafting for even the most massive of bone defect problems, but additional followup is needed to see how durable these encouraging results are over the longer term

Major bone loss involving the acetabulum can be seen during revision THA due to component loosening, migration or osteolysis and can also occur as a sequela of infected THA. Uncemented porous ingrowth components can be used for reconstruction of the vast majority of revision cases, where smaller segmental or cavitary defects are typically present. But when stable structural support on host bone is lacking, highly porous metal acetabular augments have been described as an alternative to large structural allograft. The fundamental concept behind these acetabular augments is the provision of critical additional fixation, structural support and increased contact area against host bone over the weeks following surgery while the desired ingrowth into porous implant surfaces is occurring. Three separate patterns of augment placement have been utilised in our practice since the development of these implants a decade ago: Type 1 - augment screwed onto the superolateral acetabular rim in a “flying buttress” configuration for treatment of a segmental rim defect, Type 2 – augment placed superiorly against host and then fixed to the acetabular component adjacent to the cup to fill a mainly elliptical cavitary defect, and Type 3 – augment(s) placed medial to the cup to fill a protrusio type cavitary or combined cavitary segmental defect of the superomedial or medial wall, and allow peripheral cup placement against the still intact acetabular rim. In all cases the acetabular component and augment interface is fixed together with cement, with care to prevent any cement extrusion between any implant and the bone. When possible, we now prefer to place the acetabular component first and fix it provisionally with 2 or more screws, and then place the augments second as this is technically quicker and easier. This order of insertion is only possible in type 1 and a few select type 2 cases. Type 3 cases always require placement of one or more augments first, before cup insertion. Supplemental cancellous bone graft is used routinely, but the need for structural bone is avoided. From 2000 through 2007, porous tantalum acetabular augments were used very selectively in 85 revision THA procedures out of total of the 1,789 revision hip cases performed at our institution. All cases had associated massive acetabular deficiency precluding stable mechanical support for a cup alone. Fifty-eight hips had complete radiographic and clinical follow at minimum 5 years. The majority of patients had either Paprosky type 3A defects (28/58, 48%) or 3B defects (22/58, 38%). Ten out of 58 had pre-operative pelvic discontinuities. Three separate patterns of augment placement were utilised: Type 1 - augment screwed onto the superolateral acetabular rim (21%), Type 2 – augment fixed to the acetabular component adjacent to the cup to fill a mainly elliptical cavitary defect (34%), and Type 3 – augment(s) placed medial to the cup to fill a protrusio type cavitary or combined cavitary segmental defect of the superomedial medial wall (45%). At 5 years, 2/58 (3%) were revised for aseptic loosening and another 6/58 demonstrated incomplete radiolucencies between the acetabular shell and zone 3. One of the revised cups and 5 of 6 of the cups with radiolucencies had an associated pelvic discontinuity. Highly porous metal acetabular augments are an infrequently needed, but extremely valuable, versatile and reliable adjunctive fixation method for use with uncemented acetabular components during complex revision THA associated with major bone deficiency. Smaller patients are more likely to require this approach as reaming away defects to allow insertion of a jumbo cup is more difficult with a smaller AP dimension to the acetabular columns and less local bone for implant support. Intermediate term durability and apparent radiographic incorporation has been very good despite the complex reconstructions originally required. This technique can allow the avoidance of structural bone grafting for even the most massive of bone defect problems, but additional followup is needed to see how durable these encouraging results are over the longer term

Total hip arthroplasty for developmental dysplasia of the hip (DDH) remains a difficult and challenging problem. How to reconstruct acetabular deficiencies has become increasingly important. One of the major causes inducing loosening of acetabular reinforcement ring with hook (Ganz ring) is insufficient initial stability. In this study, three-dimensional finite element models of the pelvis with different degrees of bone defect and acetabular components were developed to investigate the effects of the number of screws, screw insert position (Fig. 1), and bone graf quality on the initial stability under the peak load during normal walking. The size of pelvic bone defect, the number of screws and the position of screws were varied, according to clinical experience, to assess the change of initial stability of the Ganz ring. The Ganz ring was placed in the true acetabulum and the acetabular cup was cemented into the Ganz ring with 45 degrees abduction and 15 degrees of screws. The Insert position, nodes on the sacroiliac joint and the pubic symphysis were fixed in all degrees of freedom as the boundary condition. The peak load during normal walking condition was applied to the center of the femoral head (Fig. 2). According to the Crowe classification, as the degree of acetabular dysplasia was increased, the relative micromotion between the Ganz ring and pelvis was also increased. The peak micromotion increased as the stiffness of bone graft decreased. Increasing the numbers of screws, the relative micromotion tended to be reduced and varied the screw insertion position that affects the relative micromotion in the Ganz ring-pelvic interface (Fig. 3). This study showed that increasing the number of inserted screws can reduce the relative micromotion. Both the insert position and graft bone property affect the stability of the Ganz ring while the insert position has a greater impact. The current study is designed to lay the foundation for a biomechanical rationale that will support the choice of treatment

Anatomic reduction (subcapital re-alignment osteotomy) via surgical hip dislocation – increasingly popular. While the reported AVN rates are very low, experiences seem to differ greatly between centres. We present our early experience with the first 29 primary cases and a modified fixation technique. We modified the fixation from threaded Steinman pins to cannulated 6.5mm fully-threaded screws: retrograde guidewire placement before reduction of the head ensured an even spread in the femoral neck and head. The mean PSA (posterior slip angle) at presentation (between 12/2008 and 01/2011) was overall 68° (45–90°). 59% (17/29) were stable slips (mean PSA 68°), and 41% (12/29) were unstable slips unable to mobilise (mean PSA 67°). The vascularity of the femoral head was assessed postoperatively with a bone scan including tomography. The slip angle was corrected to a mean PSA of 5.8° (7° anteversion to 25° PSA). We encountered no complications related to our modified fixation technique. All cases with a well vascularised femoral head on the post-operative bone scan (15/17 stable slips and 8/12 unstable slips) healed with excellent short term results. Both stable slips with decreased vascularity on bone scan (2/17, 12%) had been longstanding severe slips with retrospectively suspected partial closure of the physis, which has been described as a factor for increased risk of avascular necrosis (AVN). One of these cases was complicated by a posterior redislocation due to acetabular deficiency. In the unstable group, 4/12 cases (33%) had avascular heads intra-operatively and cold postoperative bone scans, 3 have progressed to AVN and collapse. Anatomic reduction while sparing the blood supply of the femoral head is a promising concept with excellent short term results in most stable and many unstable SCFE cases. Extra vigilance for closed/closing physes in longstanding severe cases seems advisable. Regardless of treatment, some unstable cases inevitably go on to AVN

Impaction bone grafting (IBG) of the acetabulum in cemented primary total hip replacement is a useful technique in the management of acetabular deficiencies. It has the capacity to restore anatomy and bone stock with good long-term outcome. We present 125 consecutive cases of IBG with a cemented polyethylene component. All patients who received full IBG of the acetabulum in primary cemented Exeter total hip replacements and who underwent surgery between August 1995 and August 2003 were identified. All operative and follow-up data was collected prospectively and no patients were lost to follow-up. All patients underwent pre-operative and regular post-operative hip scores with the Harris, Oxford and the modified Charnley scoring systems. Data on indication, surgical technique, socket position and migration and revision was reviewed at a mean follow-up of 7.6 (range 5 to13.4) years. Between August 1995 and August 2003, 113 patients (85 females) with an average age of 67.8 (range 22.9–99.2) years underwent 125 primary Exeter cemented total hip replacements with IBG of acetabular defects. Acetabular defects were classified according to the AAOS classification as cavitatory in 62 hips and as segmental, requiring application of a rim mesh prior to IBG, in 63 hips. Life tables were constructed demonstrating 86.4% survival of the acetabular component at 13.4 years with revision for any reason as the endpoint and 89.3% survival with revision for aseptic loosening as the endpoint. Of the seven patients who underwent revision for aseptic loosening, all had pre-operative segmental acetabular defects requiring application of a rim mesh. No patient who underwent IBG for a cavitatory defect required revision surgery for aseptic loosening. Survival of the Exeter cemented femoral component was 100% at 13.4 years with revision for aseptic loosening as the endpoint. There were 11 radiographic failures of the acetabular component, which have not been revised at latest review. One of these is symptomatic but not fit for revision surgery, two were asymptomatic at time of death and eight are asymptomatic but under review. This is the largest series of IBG in the acetabulum in cemented primary THR. Our results suggest that the medium term survival of this technique is good, particularly when used for cavitatory defects. Although there were radiographic failures, these are largely asymptomatic and may not require revision

Purpose:. Acetabular bone loss during revision total hip arthroplasty (THA) poses a challenge for reconstruction as segmental and extensive cavitary defects require structural support to achieve prosthesis stability. Trabecular metal (TM) acetabular augments structurally support hemispherical cups. Positive short-term results have been encouraging, but mid- to long-term results are largely unknown. The purpose of this study was to determine the continued efficacy of TM augments in THA revisions with significant pelvic bone loss. Methods:. Radiographs and medical records of 51 patients who had undergone THA revision with the use of a TM augment were retrospectively reviewed. Acetabular defects were graded according to the Paprosky classification of acetabular deficiencies based on preoperative radiographs and operative findings. Loosening was defined radiographically as a gross change in cup position, change in the abduction angle (>5°), or change in the vertical position of the acetabular component (>8 mm) between initial postoperative and most recent follow-up radiographs (Figure 1). Results:. Eleven patients had incomplete radiographic follow-up and were excluded. The study population included 17 men and 23 women, averaging 68.1 ± 14.1 years of age (range, 37–91), with average radiographic follow-up of 19.0 months (range, 2.4–97.4). Reasons for revision included osteolysis (n = 20, 38.5%), component loosening (n = 18, 15.4%), and periprosthetic fracture (n = 6, 11.5%). All patients underwent revision THA using a TM multi-hole revision acetabular cup and TM acetabular augment(s) to fill bony defects. Morcellized allograft was used in 9 patients. There were 33 Paprosky Type IIIA and seven Paprosky Type IIIB defects. One patient with Paprosky Type IIIB had catastrophic failure of the reconstructive construct three months postoperatively. The remaining 39 acetabular revisions demonstrated signs of bony ingrowth at the latest follow-up. There were no radiolucent lines suggestive of loosening, and no significant differences in abduction angle (p = 0.78), vertical distance between the superolateral edge of the cup and the trans-ischial reference line (p = 0.96), or the vertical distance between the center of the femoral head and trans-ischial reference line (p = 0.75) between the initial postoperative and most recent follow-up radiographs (Figure 2). Discussion and Conclusion:. Achieving fixation and long-term stability in THA revisions with segmental and/or cavitary bone loss is challenging. TM augments provide a modular structural system to achieve bony ingrowth, while avoiding large structural allografts, cages, and custom implants. At latest follow-up, 39 revision hips remained well-fixed with no evidence of loosening. One patient with a significant surgical history of infection, periprosthetic femur fracture, and 2 prior revision surgeries before acetabular reconstruction had an early clinical failure. Trabecular metal augments can be used for reconstruction of acetabular bone loss with good mid-term results. Continued follow-up is warranted for radiographic evaluation of bony integration and implant stability to determine long-term survivorship of these implants

The number of joint revision surgeries is rising, and the complexity of the cases is increasing. In 58% of the revision cases, the acetabular component has to be revised. For these indications, literature decision schemes [Paprosky 2005] point at custom pre-shaped implants. Any standard device would prove either unfeasible during surgery or inadequate in the short term. Studies show that custom-made triflanged implants can be a durable solution with good clinical results. However, the number of cases reported is few confirming that the device is not in widespread use. Case Report. A patient, female 50 yrs old, diagnosed having a pseudotumor after Resurfacing Arthroplasty for osteo-arthritis of the left hip joint. The revision also failed after 1 y and she developed a pelvic discontinuity. X-ray and Ct scans were taken and sent to a specialized implant manufacturer [Mobelife, Leuven, Belgium]. The novel process of patient-specific implant design comprises three highly automated steps. In the first step, advanced 3D image processing presented the bony structures and implant components. Analysis showed that anterior column was missing, while the posterior column was degraded and fractured. The acetabular defect was diagnosed being Paprosky 3B. The former acetabular component migrated in posterolateral direction resulting in luxation of the joint. The reconstruction proposal showed the missing bone stock and anatomical joint location. In the second step, a triflanged custom acetabular metal backing implant was proposed. The bone defect (35ml) is filled with a patient-specific porous structure which is rigidly connected to a solid patient-specific plate. The proposed implant shape is determined taking into account surgical window and surrounding soft tissues. Cup orientation is anatomically analyzed for inclination and anteversion. A cemented liner fixation was preferred (Biomet Advantage 48mm). Screw positions and lengths are pre-operatively planned depending on bone quality, and transferred into surgery using jig guiding technology (Materialise NV, Leuven, Belgium). In the third step, the implant design was evaluated in a fully patient-specific manner in dedicated engineering (FEA) software. Using the novel automated CT-based methodology, patient-specific bone quality and thickness, as well as individualised muscle attachments and muscle and joint forces were included in the evaluation. Implants and jig were produced with Additive Manufacturing techniques under ISO 13485 certification, using respectively Selective Laser Melting (SLM) techniques [Kruth 2005] in medical grade Ti6Al4V material, and the Selective Laser Sintering technique using medical grade epoxy monomer. The parts were cleaned ultrasonically, and quality control was performed by optical scanning [Atos2 scanning device, GOM Intl. AG, Wilden, Switzerland]. Sterilization is performed in the hospital. CONCLUSION. A unique combination of advanced 3D planning, patient-specific designed and evaluated implants and drill guides is presented. This paper illustrates, by means of a clinical case, the novel tools and devices that are able to turn reconstruction of complex acetabular deficiencies into a reliable procedure

Down syndrome (DS), is a genetic disorder caused by a third copy of the 21st chromosome (Trisomy 21), featuring typical facial characteristics, growth delays and varying degrees of intellectual disability. Some degree of immune deficiency is variably present. Multiple orthopaedic conditions are associated, including stunted growth (90%), ligamentous laxity (90%), low muscle tone (80%), hand and foot deformities (60%), hip instability (30%), and spinal abnormalities including atlanto-axial instability (20%) and scoliosis. Hip disease severity varies and follows a variable time course. Rarely a child presents with DDH, but during the first 2 years the hips are characteristically stable but hypermobile with well-formed acetabulae. Spontaneous subluxation or dislocation after 2 presents with painless clicking, limping or giving way. Acute dislocation is associated with moderate pain, increased limp and reduced activity following minor trauma. Hips are reducible under anesthesia, but recurrence is common. Eventually concentric reduction becomes rarer and radiographic dysplasia develops. Pathology includes: a thin, weak fibrous capsule, moderate to severe femoral neck anteversion and a posterior superior acetabular rim deficiency. A number of femoral and acetabular osteotomies have been reported to treat the dysplasia, with acetabular redirection appearing to be most successful. However, surgery can be associated with a relatively high infection rate (20%). Additionally, symptomatic femoral head avascular necrosis can occur as a result of slipped capital femoral epiphysis. Untreated dysplasia patients can walk with a limp and little pain into the early twenties even with fixed dislocation. Pain and decreasing hip function is commonly seen as the patient enters adult life. Occasionally the hip instability begins after skeletal maturity. Total hip arthroplasty (THA) is the standard treatment when sufficient symptoms have developed. The clinical outcomes of 42 THAs in patients with Down syndrome were all successfully treated with standard components. The use of constrained liners to treat intra-operative instability occurred in eight hips and survival rates were noted between 81% and 100% at a mean follow-up of 105 months (6 – 292 months). A more recent study of 241 patients with Down syndrome and a matched 723-patient cohort from the Nationwide Inpatient Sample compared the incidence of peri-operative medical and surgical complications in those who underwent THA. Compared to matched controls, Down syndrome patients had an increased risk of complications: peri-operative (OR, 4.33; P<.001), medical (UTI & Pneumonia OR, 4.59; P<.001) and surgical (bleeding OR, 3.51; P<.001), Mean LOS was 26% longer (P<.001). While these patients can be challenging to treat, excellent surgical technique and selective use of acetabular constraint can reliably provide patients with excellent pain-relief and improved function. Pre-operative education of all clinical decision makers should also reinforce the increased risk of medical and surgical complications (wound hemorrhage), and lengths of stay compared to the general population

Introduction. Acetabular bone deficiency, especially proximal and lateral deficiency, is a difficult technical problem during primary total hip arthroplasty (THA) in developmental hip dysplasia (DDH). We report a configuration-based classification of hip, including a definition of shallow acetabulum. We also report a new reconstruction method using a medial reduced cemented socket and additional bulk bone in conjunction with impaction morselized bone grafting (Ad-BBG method). We aimed to evaluate usefulness of the classification and the method's clinical/radiographic outcomes. Methods. Forty percent of 330 THAs for DDH were defined as shallow dysplastic hips. The Ad-BBG method was performed on 102 hips (78% of shallow hips). For the 24 remaining hips, THA was performed using the conventional interposition bulk bone grafting (8 hips)or without bone grafting by using rigid lateral osteophyte (16 hips). Operative Technique: Theresected femoral head was sectioned at 1–2-cm thickness, and a suitable size of the bulk bone graft was placed on the lateral iliac cortex and fixed by polylactate absorbable screws. Autogenous impaction morselized bone grafting, with or without hydroxyapatite granules, was performed along with the implantation of medial reduced cemented socket. Radiographic criteria used for determining loosening were migration or a total radiolucent zone between the prosthesis/bone cement and host bone. The follow-up period was 10.2 ± 2.6 (range, 6.0–15.0) years. Results. Acetabular component was revised in only one case with a shallow and Crowe Type IV acetabulum. Within 2 years postoperatively, most Ad-BBGs cases showed successful bone remodeling and bone graft reorientation without collapse on radiographs. Discussion and Conclusions. Osteointegration and mid-term good clinical outcomes were achieved in acetabular reconstruction for primary THA using the medial reduced cemented socket and bone grafting methods including the Ad-BBG technique in conjunction with impaction morselized bone grafting for shallow dysplastic hip

Total hip arthroplasty (THA) is frequently performed as a salvage procedure for the acetabular fracture when posttraumatic osteoarthritis, posttraumatic avascular necrosis, or fixation failure with subluxation develop. Special considerations for this situation include previous surgical exposure with dense scar tissue, the type and location of implants, the location and amount of heterotopic ossification, indolent infection, previous sciatic nerve palsy, and the pathoanatomy of existing acetabular defect. These factors can influence the choice of surgical exposure and the reconstructive method. The outcomes of THA after acetabular fracture are generally less favorable than those of the nontraumatic degenerative arthritis. Reason for this high failure is the low mean age and the high activity level of the patient. Other important reasons for failure include the problem of acetabular bone deficiency and compromised bone quality. We evaluated the results of cementless THA in patient who had previous acetabular fracture. We also compared this result with those of patients with posttraumatic avascular necrosis of the femoral head. Forty-five consecutive cementless THAs were performed for the treatment of post-traumatic osteoarthritis after acetabular fracture between December 1993 and December 2008. Of these patients, 15 patients were died or lost to follow-up monitoring before the end of the minimum one year follow-up period. This left 30 patients (30 hips) as the subjects of our retrospective review. We evaluated the clinical and radiographic results of these patients and compared with the results of THA in patients with post-traumatic AVN of the femoral head which had without acetabular damage. Two hips required revision of the cup secondary to early migration of the acetabular cup (1 hip) and postoperative deep infection (1 hip). There was no significant difference in clinical and radiographic results between two groups except implanted acetabular component size and required bone graft (p<0.05). The Kaplan-Meier ten-year survival rate, with revision as the end-point, was 90% and 96.7% with loosening of acetabular component as the end-point. Our series suggested that compared with cemented components, uncemented sockets may improve the results of arthroplasty after previous acetabular fracture. In conclusion, cementless THA following acetabular fracture presents unique challenge to the surgeon, careful preoperative assessment and secure component fixation with proper bone grafting is essential to minimize problems

Introduction. Acetabular bone deficiency, especially proximal and lateral deficiency, is a difficult technical problem during primary total hip arthroplasty (THA) in developmental hip dysplasia (DDH). We report a configuration-based acetabular classification, a modification of the Crowe's classification, of DDH, including a definition of shallow acetabuli. We also report a new reconstruction method using a medial reduced cemented socket andadditional bulk bone in conjunction with impaction morselized bone grafting (Ad-BBG method). We aimed to evaluate usefulness of the classification and the method's clinical/radiographic outcomes. Methods. One hundred thirty one hips of 330 THAs for DDH (40%) were defined shallow. The Ad-BBG methodwas performed on 102 hips (78% shallow hips). For the 24 remaining hips, THA was performed using the conventional interposition bulk bone grafting (Ip-BBG) (8 hips)or without bone grafting by using rigid lateral osteophyte (16 hips). Japanese Orthopaedic Association (JOA) scores and the Merle d'Aubigne and Postel (M&P) scores were used in follow-up; radiographs were analyzed retrospectively. The criteria used for determining loosening were migration or a total radiolucent zone between the prosthesis/bone cement and host bone. The follow-up period was 9.2 ± 2.6 (range, 5.0–14.0) years. Operative Technique. Theresected femoral head was sectioned at 1–2-cm thickness, and a suitable size of the bulk bone graft was placed on the lateral iliac cortex and fixed by polylactate absorbable screws. Autogenous impaction morselized bone grafting, with or without hydroxyapatite granules, was performed along with the implantation of medial reduced cemented prosthetic hip socket. The same surgical team performed all surgical procedures. Results. Acetabular component was revised in only one case with a shallow and Crowe Type IV acetabulum. The mean JOA and M&P scores improved from preoperative 39.3 and 6.8 points to postoperative 93.9 and 17.2 points, respectively. Within 2 years postoperatively, most Ad-BBGs cases showed successful bone remodeling and bone graft reorientation on radiographs. Conclusions. We had good results of acetabular reconstruction in primary THA using the medial reduced cemented socket and bone grafting methods including the Ad-BBG technique in conjunction with impaction morselized bone grafting for shallow dysplastic hip. Osteointegration and good clinical outcomes were achieved in most cases. However, long-term outcomes should be subject of further investigation. Summary. Reconstruction methods for shallow dysplastic hip using medial reduced cemented socket and additional bulk bone grafting in conjunction with impaction morselized bone grafting are presented

Purpose. The purpose of the present study is to assess 5–10 years' follow-up results after acetabular impaction bone grafting (IBG) in primary cemented total hip arthroplasty (THA) for cases with acetabular bone defect. Patients and methods. We performed 36 primary cemented THA with acetabular IBG in 33 patients between November 2004 and May 2009. As one patient died due to unrelated disease at 6 months after the surgery, 35 hips of 32 patients were included in this study. The average age at the surgery was 62.4 years, and the average follow-up period was 7.9 years (5–10 years). Diagnoses were osteoarthritis due to acetabular dysplasia in 28 hips (26 patients), Rheumatoid arthritis (RA) in 4 hips (3 patients), rapidly destructive coxopathy (RDC) in 1 hip (1 patient), idiopathic acetabular protrusion in 1 hip (1 patient), and acromegaly in 1 hip (1 patient). For clinical assessment, the Merle d'Aubigné and Postel hip score was assessed and degree of post-operative improvement was classified according to their method as very great improvement, great improvement, fair improvement, and failure. Perioperative complications were also recorded. Acetabular bone defects were assessed at the surgery and categorized using AAOS acetabular bone defect classification system. For radiological assessment, anteroposterior radiographs of the bilateral hip joints were analyzed preoperatively and post-operatively. Radiolucent lines (RLL) of more than 2 mm around the acetabular components were assessed using the DeLee and Charnley zone classification. Acetabular component loosening was assessed according to the Hodgkinson et al. classification system, and type 3 (complete demarcation line) and type 4 (migration) were classified as “loosening”. Results. The mean Merle d'Aubigné and Postel hip score improved from 9.8 points before the operation to 15.9 points at the final follow-up. Degree of post-operative improvement was assessed as “very great” in 11 hips, “great” in 23 hips and “fair” in 1 hip. Dislocation, DVT, and infection were recorded in 1 hip, 1 hip, and 1 hip, respectively. Re-operation was performed for the acute infection (without loosening) case at 5.3 years after the primary THA. Acetabular bone defects were classified as segmental defect (AAOS type I) in 29 hips, cavitary defect (AAOS type II) in 3 hips and combined segmental and cavitary defect (AAOS type III) in 3 hips. Metal meshes were used for segmental defects of 29 AAOS type I hips and 2 AAOS type III hips, and for medial wall defect of 1 AAOS III hip. On radiographic assessment, no metal device breakage was detected during the follow-up period. There were no clear lines around the cup and all cups were assessed as stable at the final follow-up. Conclusion. Acetabular impaction bone grafting in primary cemented THA is technically demanding procedure. However, postoperative functional improvement is remarkable and stable radiographic findings were achievable independent from original diagnoses. This procedure is one of useful options to restore acetabular bone deficiency in cemented primary THA for cases with acetabular bone defect