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Revision total hip arthroplasty (rTHA) presents significant challenges, particularly in patients with severe acetabular bone defects. Traditional treatment options often fall short, leading to the emergence of custom-made 3D-printed acetabular implants. Accurate assessment of implant positioning is crucial for ensuring optimal postoperative outcomes and for providing feedback to the surgical team. This single-center, retrospective cohort study evaluates the accuracy of standard 2D radiographs versus 3D CT scans in assessing the positioning of these implants, aiming to determine if 2D imaging could serve as a viable alternative for the postoperative evaluation. We analyzed the implant positions of seven rTHA patients with severe acetabular defects (Paprosky ≥ Type IIIA) using an alignment technique that integrates postoperative 2D radiographs with preoperative CT plans. Two independent investigators, one inexperienced and one experienced, measured the positioning accuracy with both imaging modalities. Measurements included translational shifts from the preoperatively templated implant position in the craniocaudal (CC), lateromedial (LM), and ventrodorsal (VD) directions, as well as rotational differences in anteversion (AV) and inclination (INCL). The study demonstrated that 2D radiographs, when aligned with preoperative CT data, could accurately assess implant positions with precision nearly comparable to that of 3D CT scans. Observed deviations were 1.4 mm and 2.7 mm in CC and LM directions, respectively, and 3.6° in AV and 0.7° in INCL using 2D imaging, all within clinically acceptable ranges. For 3D CT assessments, mean interobserver variability was up to 0.9 mm for translational shifts and 1.4° for rotation, while for 2D alignment, observer differences were 1.4 mm and 3.2° for translation and rotation, respectively. Comparative analysis of mean results from both investigators, across all dimensions (CC, LM, AV, and INCL) for 2D and 3D matching, showed no significant differences. In conclusion, conventional anteroposterior 2D radiographs of the pelvis can sufficiently determine the positioning of custom-made acetabular implants in rTHA. This suggests that 2D radiography is a viable alternative to 3D CT scans, potentially enhancing the implementation and quality control of advanced implant technologies.

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Large acetabular bone defects are challenging in hip revision surgery. Clinical assessment is crucial to evaluate modern technologies in surgical reconstruction. We aimed to better understand the bone remodeling that occurs following acetabular reconstruction. Our objectives were: (1) To characterize changes in the shape of the pelvis by studying sequential computed tomography (CT) scans collected immediately and 1-year postoperatively and (2) to identify which part of the pelvis is most susceptible to remodeling. We used the CT scans taken at two timepoints, of 24 patients with acetabular bone defects classified as Paprosky IIIB, treated with three-dimensional (3D)-printed custom-made acetabular implants. Segmented 3D models of the bony pelvis were co-registered using three different techniques. A global co-registration of the full pelvis was conducted, followed by the co-registration of the innominate bone and then ilium only, on the ipsilateral reconstructed side. The relative movements of the ilium, ischium, and pubis were analyzed from visual inspection and using co-registration metrics (root mean square error and intersection over union). No bone remodeling was found in 14/24 patients (58%). The co-registration of the innominate bone indicated bone remodeling in five cases (21%), while the remaining five cases (21%) presented remodeling in the global co-registration but not the innominate bone co-registration, suggestive of changes occurring at the sacroiliac joint. Changes in the pelvic shape were greatest at the pubis and ischium. Bone remodeling may occur in complex cases of Paprosky type IIIB defects, after acetabular reconstruction (occurrence of 21%, 5/24 cases). Surgeons and engineers should consider this when monitoring implant migration.

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Background: Trabecular metal augments (TMAs) have been extensively used in revision total hip arthroplasty (THA) to address acetabular bone defects. However, limited data exists regarding TMA utilization during primary THA. This study aims to assess the clinical and radiographic outcomes of TMAs used during primary THA. Methods: A single-institution retrospective case series of primary THA patients treated with TMA between 2010 and 2019 was performed. Patient demographics, complications, and revisions were recorded. Cup position, center of rotation, leg length, and radiolucent lines were assessed radiographically. The Kaplan-Meier method was used to compute implant survivorship. Results: Twenty-six patients (30 hips) were included with average age of 52.6 ± 15.3 years (range: 22-78) and mean follow-up of 4.1 ± 2.1 years (range: 2.0-8.9). Most TMAs were indicated for developmental dysplasia of the hip (n = 18; 60.0%). On average, hip center of rotation was lowered 1.5 ± 1.3 cm and lateralized 1.2 ± 1.5 cm, while leg length and global offset were increased by 2.4 ± 1.2 cm and 0.4 ± 1.0 cm, respectively. At final follow-up, 3 hips (10.0%) required revision: one (3.3%) for aseptic loosening and 2 (6.7%) for instability. No patients had progressive radiolucent lines at final follow-up. Five-year survival with aseptic loosening and all-cause revision as endpoints was 100% (95% confidence interval: 90.0%-100.0%) and 92.1% (95% confidence interval: 81.3%-100.0%), respectively. One patient required revision for aseptic loosening after the 5-year mark. Conclusions: Trabecular metal augmentation during primary THA demonstrates satisfactory early to mid-term outcomes. TMA is a viable option for complex primary THA when bone loss is encountered or secondary support is required. Level of Evidence: Level IV.

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BACKGROUND: Acetabular bone loss is a technical challenge in total hip arthroplasty (THA). This study sought to report the functional and radiological results of acetabular reconstruction using impaction bone grafting (IBG) in patients with acetabular bone deficiency undergoing primary or revision THA. METHODS: In this prospective study, full history taking, preoperative clinical and radiological evaluation, and preoperative planning and templating were performed. The Paprosky classification and the American Academy of Orthopaedic Surgeons classification were used to assess the acetabular deficiencies. Clinical outcomes were assessed utilizing the Harris hip score (HHS) and a 4-question satisfaction questionnaire. Graft incorporation was evaluated in the last follow-up X-rays. RESULTS: This study included 50 patients with a mean age of 46.7 ± 15.3 years. The THA was primary in 14 (28%) patients and revision in 36 (72%) patients. The mean HHS improved significantly from 28.8 ± 24.1 preoperatively to 76.6 ± 6.1, with a mean follow-up period of 23 months. Overall, 88% of patients were very satisfied. Complete radiological graft incorporation to host bone was achieved in 35 (70%) patients, and the remaining patients had partial incorporation. Complete graft incorporation was associated more frequently with primary THA, autografts, cementless cups, decreased defect size, and decreased graft layer thickness. CONCLUSIONS: IBG for acetabular reconstruction in THA can achieve excellent clinical and radiological outcomes with a low complication rate. LEVEL OF EVIDENCE: Level IV.

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Purpose: This is a systematic review and meta(regression) analysis to assess the performance of custom triflange acetabular components (CTAC) in total hip arthroplasty (THA) revision surgery. Implant-related complications, failure rate, functional outcomes and implant and surgical technique-related predictors for outcome were assessed. Methods: This systematic review was performed according to PRISMA guidelines and registered with PROSPERO (2020 CRD42020209700). PubMed, Embase, Web of Science, COCHRANE Library and Emcare were searched. Studies on Paprosky type 3A and 3B or AAOS type 3 and 4 acetabular defects with a minimum follow-up of 12 months and cohorts > 10 patients were included. Results: Thirty-three studies were eligible for inclusion (n = 1235 hips, 1218 patients). The methodological quality of the studies was moderate (AQUILA: 7.4/11 points). Considerable heterogeneity was observed in terms of complications, re-operations and implant failure reporting. The total incidence of implant-related complications was 24%. The incidence of re-operation for any reason was 15%, and the implant failure rate was 12% at a mean of 46.9 months and the post-operative Harris Hip Score improved by a mean of 40 points. Several predictors for outcome were found, such as implant generation, follow-up length and study start date. Conclusions: The use of CTAC in revision THA has satisfactory complication and implant failure rates. The CTAC technique improves post-operative clinical outcomes and the meta-regression analysis showed that there is a clear association between improvements in the CTAC performance and the evolvement of this technique over time.

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Introduction: Developmental dysplasia of the hip (DDH) is the cause of 2.6-9.1% of all total hip prostheses implanted at any age and constitutes a challenge in revision surgeries. Objective: To present a case of severe acetabular dysplasia managed by the Stoppa-type approach. The Case: We report a case of a 26-year-old male patient with DDH initially treated with total hip replacement and then diagnosed with aseptic loosening (Paprosky 3A). Using a modified Stoppa approach; acetabular augmentation and bone autograft attached with endopelvic reconstruction plates were performed. Two years after the procedure our patient is asymptomatic, has no restrictions on his daily living activities, and is very satisfied with the result. Conclusions: The Stoppa approach was very useful for the endopelvic reconstruction of the acetabular roof, so it may be an option to treat severe acetabular defects. Level of evidence: IV.

Introducción: La displasia del desarrollo de cadera (DDH, por sus siglas en inglés) es la causa del 2,6-9,1 % del total de prótesis de cadera implantadas a cualquier edad y constituye un reto en las cirugías de revisión. Objetivo: Presentar un caso de displasia acetabular grave manejado por abordaje tipo Stoppa. El caso: Presentamos un caso de un paciente masculino de 26 años con DDH tratado inicialmente con reemplazo total de cadera y luego diagnosticado con aflojamiento aséptico (Paprosky 3A). Se utilizó un enfoque Stoppa modificado. Se realizó aumento acetabular y autoinjerto óseo unido con placas de reconstrucción endopélvica. Dos años después del procedimiento, el paciente es asintomático, no tiene restricciones en sus actividades de la vida diaria y está muy satisfecho con el resultado. Conclusiones: El abordaje de Stoppa fue muy útil para la reconstrucción endopélvica del techo acetabular, por lo que puede ser una opción para tratar defectos acetabulares graves. Grado de comprobación: IV.

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BACKGROUND: Post-operative dislocation and reconstruction of acetabular defects are two challenging topics in revision Total Hip Arthroplasty (rTHA). Cemented Dual Mobility (DM) cups on top of Kerboull Cross and bone graft have been successfully employed to overcome these challenges. The cementless augmented DM cups were recently introduced. In this study medium term results of the augmented cementless DM Coptos cups are reported and compared to the established technique of cemented DM cups and Kerboull plate. MATERIAL AND METHODS: This is a retrospective analysis of data collected on patients who received rTHA using DM cups in the period between June 2015 and September 2020. Two groups of patients were identified. The first group received cementless augmented DM-cups (NOVAE® Coptos TH-SERF) (Coptos TH cup group). The second comparable group who had Kerboull ring (KE ring group) and cemented DM cups (NOVAE® STICK). Demographic data, surgical technique, functional and radiological outcome as well as complications during the follow-up visits are reported. RESULTS: Forty-two patients with a mean age at the time of revision 48.8 ± 13.6 years. 29 patients received Coptos TH DM-cup, while 13 patients had Bone Graft (BG), KE ring and cemented DM cups for acetabular reconstruction. Acetabular defects were Paprosky types IIB and IIC in 31 patients and IIIA and B in 11 patients. The follow-up was 52.8 ± 21 months (mean ± STD); and the mean Harris Hip Score (HHS) at last visit was 91 ± 5. Good stability of all cups was reported. Full integration of the impaction graft was observed in 94% of the Coptos and 92% of the KE groups. One of the Coptos cups was readjusted and one case of single dislocation was recorded in the KE group. None of the DM cups in both groups was revised or awaiting revision. CONCLUSION: Coptos TH cups achieve similar results to the cemented DM on KE ring at the medium term but long term outcome remains to be seen.

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BACKGROUND: Increases in the numbers of surgical procedures for primary total hip arthroplasty (THA) inevitably lead to increases in the requirements for revision THA. The achievement of long-term stability is difficult or impossible by conventional implants in patients with severe destruction of the acetabulum. OBJECTIVE: This case report presents a successful treatment using a specific three-dimensional (3D)-printed porous titanium acetabular composite component without a flange in the management of Paprosky type IIIB acetabular defects. METHOD: A 65-year-old female diagnosed with right hip prosthetic loosening with a huge acetabular defect presented to our hospital. We designed the 3D model of the pelvis and created an individualized 3D-printed porous titanium acetabular composite component for revision THA. The procedure was performed through a posterolateral approach, and the component was implanted in the defect and fixed with cup screws using the drill guides. RESULTS: At the last follow-up at 2 years, the patient had a satisfactory hip joint function and no signs of loosening or other complications were found. CONCLUSIONS: The 3D-printed porous titanium acetabular composite component without a flange is showing promising clinical and radiological outcomes in the management of Paprosky type III acetabular defects.

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AIMS: Large acetabular bone defects encountered in revision total hip arthroplasty (THA) are challenging to restore. Metal constructs for structural support are combined with bone graft materials for restoration. Autograft is restricted due to limited volume, and allogenic grafts have downsides including cost, availability, and operative processing. Bone graft substitutes (BGS) are an attractive alternative if they can demonstrate positive remodelling. One potential product is a biphasic injectable mixture (Cerament) that combines a fast-resorbing material (calcium sulphate) with the highly osteoconductive material hydroxyapatite. This study reviews the application of this biomaterial in large acetabular defects. METHODS: We performed a retrospective review at a single institution of patients undergoing revision THA by a single surgeon. We identified 49 consecutive patients with large acetabular defects where the biphasic BGS was applied, with no other products added to the BGS. After placement of metallic acetabular implants, the BGS was injected into the remaining bone defects surrounding the new implants. Patients were followed and monitored for functional outcome scores, implant fixation, radiological graft site remodelling, and revision failures. RESULTS: Mean follow-up was 39.5 months (36 to 71), with a significant improvement in post-revision function compared to preoperative function. Graft site remodelling was rated radiologically as moderate in 31 hips (63%) and strong in 12 hips (24%). There were no cases of complete graft site dissolution. No acetabular loosening was identified. None of the patients developed clinically significant heterotopic ossification. There were twelve reoperations: six patients developed post-revision infections, three experienced dislocations, two sustained periprosthetic femur fractures, and one subject had femoral component aseptic loosening. CONCLUSION: Our series reports bone defect restoration with the sole use of a biphasic injectable BGS in the periacetabular region. We did not observe significant graft dissolution. We emphasize that successful graft site remodelling requires meticulous recipient site preparation.Cite this article: Bone Jt Open 2022;3(12):991-997.

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BACKGROUND: The annual rate of primary THA has been increasing with new designs promoting THA in the younger population, therefore increasing rates and complexity of hip revision surgeries. Different types of acetabular defects in hip revisions, usually make the use of primary cementless cups quite difficult. In complex defects, using cages with cemented cups or combining cementless cups with metal augments, are possible reconstruction solutions. The Delta TT acetabular revision system provides a solution to complex defects combining the advantages of both cage construct and primary implants, with modularity that helps restore anatomical hip centre and biomechanics. The aim of this study is to evaluate the short-term results of the use of the Delta TT revision system in acetabular revision surgeries. TYPE OF THE STUDY: A retrospective case series. METHODS: 24 patients underwent acetabular revision using (Delta TT) revision system, from 2018 to 2021. The mean follow-up was 20.75 months. Clinical and functional outcomes were assessed using Harris Hip Score. RESULTS: The use of the Delta TT revision system in acetabular revision surgery provided adequate pain relief, and early patient mobilization. The preoperative HHS mean of 29.88 improved to a mean of 85.21, at the last, follow-up. None of the patients developed periprosthetic infection or loosening or nerve palsy during the follow-up period. CONCLUSION: Short-term clinical outcomes for the use of the Delta TT revision cup system in acetabular revision are encouraging with good functional outcomes and patient satisfaction.

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OBJECTIVE: To investigate the application of impaction bone grafting (IBG) combined with Ti-alloy mesh for acetabular bone defect reconstruction in total hip arthroplasty (THA) revision and follow up the clinical outcomes and imaging findings. METHODS: The clinical and imaging data of patients who were admitted to our hospital from January 2000 to December 2020 and underwent acetabular bone defects reconstruction using IBG combined with titanium mesh were retrospectively analyzed. Preoperative and post-revision Oxford and Harris scores, and post-revision complications were evaluated. Radiographs were used to determine center of rotation (COR) of the hip joint, transparency line, bone graft fusion, and bone mineral density (BMD) around the hip joint. RESULTS: Significant improvement was observed in both Oxford and Harris scores (P < 0.05). The radiographs taken at the last follow-up examination showed no significant differences in the acetabulum COR, offsets, inclination angle, mean ratio of vertical value, and BMD analysis between the post-revision side and contralateral side (P > 0.05). The follow-up data showed restoration of the mesh implant and graft bone fusion. CONCLUSIONS: The application of IBG combined with titanium-alloy mesh in revision THA patients with acetabular defects was found to provide satisfactory outcomes. However, large-scale studies are still needed to further elucidate the long-term outcomes.

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INTRODUCTION: In conjunction with impaction bone grafting (IBG), metal meshes have been proposed to minimise defects of the medial and superolateral walls in order to convert combined complex uncontained segmental defects into contained cavitary defects to facilitate IBG. METHODS: The US National Library of Medicine (PubMed/MEDLINE), EMBASE, and the Cochrane Database of Systematic Reviews were queried for publications from January 1980 to March 2019 utilising keywords pertinent to total hip arthroplasty (THA), acetabular impaction bone grafting, clinical or functional outcomes, revision THA, or postoperative complications. RESULTS: 7 articles were found to be suitable for inclusion in the present study. The mean modified Coleman methodology score for methodological deficiencies of the studies was 45.3 (range 38-59). Severe acetabular bone loss was present in 56% of cases having moderate bone loss in 18%, and mild in 26%. The all-cause reoperation rate was 7.4%, while the all-cause revision rate of the acetabular component was 6.2%. CONCLUSIONS: IBG with mesh is effective for selected patients with acetabular bone defects. Most patients with moderate bone loss as well as selected patients with large superolateral defects can be successfully treated with IBG combined with mesh. There is limited data to show that IBG with mesh might be associated with decreased survival rates in patients with severe lateral defects (Paprosky IIIA) combined with ischial or medial wall osteolysis who require combined medial and lateral meshes. In addition, patients with severe superomedial migration of the cup (Paprosky IIIB) should not be treated with IBG and mesh.

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AIMS: After failed acetabular fractures, total hip arthroplasty (THA) is a challenging procedure and considered the gold standard treatment. The complexity of the procedure depends on the fracture pattern and the initial fracture management. This study's primary aim was to evaluate patient-reported outcome measures (PROMs) for patients who underwent delayed uncemented acetabular THA after acetabular fractures. The secondary aims were to assess the radiological outcome and the incidence of the associated complications in those patients. METHODS: A total of 40 patients underwent cementless acetabular THA following failed treatment of acetabular fractures. The postoperative clinical and radiological outcomes were evaluated for all the cohort. RESULTS: The median (interquartile range (IQR)) Oxford Hip Score (OHS) improved significantly from 9.5 (7 to 11.5), (95% confidence interval (CI) (8 to 10.6)) to 40 (39 to 44), (95% CI (40 to 43)) postoperatively at the latest follow-up (p < 0.001). It was worth noting that the initial acetabular fracture type (simple vs complex), previous acetabular treatment (ORIF vs conservative), fracture union, and restoration of anatomical centre of rotation (COR) did not affect the final OHS. The reconstructed centre of rotation (COR) was restored in 29 (72.5%) patients. The mean abduction angle in whom acetabular fractures were managed conservatively was statistically significantly higher than the surgically treated patients 42.6° (SD 7.4) vs 38° (SD 5.6)) (p = 0.032). We did not have any case of acetabular or femoral loosening at the time of the last follow-up. We had two patients with successful two-stage revision for infection with overall eight-year survival rate was 95.2% (95% CI 86.6% to 100%) with revision for any reason at a median (IQR) duration of follow-up 50 months (16 to 87) months following THA. CONCLUSION: Delayed cementless acetabular THA in patients with previous failed acetabular fracture treatments produces good clinical outcomes (PROMS) with excellent survivorship, despite the technically demanding nature of the procedure. The initial fracture treatment does not influence the outcome of delayed THA. In selected cases of acetabular fractures (either nondisplaced or with secondary congruency), the initial nonoperative treatment neither resulted in large acetabular defects nor required additional acetabular reconstruction at the time of THA. Cite this article: Bone Jt Open 2021;2(12):1067-1074.

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OBJECTIVE: To compare rapid prototyping technology (RP tech) in revision total hip arthroplasty (RTHA) with traditional examination methods and to see how they are different in evaluating acetabular anatomy and designing surgical procedure. METHODS: From February 2014 to March 2018, 43 RTHA patients with complex acetabulum defects were enrolled in this prospective study regardless of age or gender. Incomplete and unclear data were excluded. Three types of radiographic examination were performed on each patient before the revision surgery. Four groups of evaluations were designed: (i) X-ray; (ii) computed tomography (CT-scan); (iii) RP tech; and (iv) CT-aided RP tech. Discrepancies between preoperative radiographic analysis and intra-operative findings were separately compared by a team of surgeons. Premade surgical plans based on each evaluation method were compared with the final surgical procedure. The compliance of anatomic evaluation and surgical plan-design based on 3D RP tech and traditional radiographs were ranked manually by a of team surgeons into: (i) complete accordance; (ii) general accordance; and (iii) undetermined structure/procedure. The difference in ranks between RP tech and traditional radiographic methods were analyzed with a nonparametric Kruskal-Wallis test. P < 0.05 was considered significant. Multiple adjustments were taken for the statistical tests level according to the Bonferroni method. RESULTS: For anatomic analysis, the accordance in four groups of evaluating methods differed from each other (P < 0.05) except for the comparison of RP tech and CT-aided RP tech. RP tech displayed better anatomic evaluating accuracy than traditional methods (X-ray and CT) with the "complete accordance" rates of these groups being 88.37%, 4.65% and 27.91%, respectively. But CT-aided RP tech did not improve accuracy significantly compared with using RP tech individually, although the value seems high in the CT-aided RP group with the "complete accordance" rate of 95.35%. For surgery design, RP tech significantly showed better applicable surgical design compared with X-ray and CT (P < 0.05), and the "complete accordance" rates were 88.37%, 6.98% and 23.26%, but no significant difference was observed between RP tech and CT-aided RP tech, and the "complete accordance" rate of CT-aided RP tech group was 97.67%. RP tech showed remarkable improvement in bone defect assessment and surgical plan design. CONCLUSION: Using RP technology improved both sensibility and accuracy in acetabular defect evaluation with better locating and evaluating efficiency compared with X-ray and CT-scans. It also improved surgical schedule designing in complex acetabular defecting revision surgery. In particularly complex cases, CT aided RP tech may increase the accuracy of RP tech.

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PURPOSE: Reconstruction of extensive acetabular bone defects is one of the most challenging problems encountered by arthroplasty surgeons. Triflange patient matched implants (PMI) offer the potential advantages of immediate, rigid fixation with a superior individualized fit. The purpose of this study was to evaluate the clinical and radiographic midterm results of PMI in extensive acetabular defect reconstruction. MATERIALS AND METHODS: The current prospectively designed retrospective review examined 13 consecutive patients (5 males and 8 females) with a mean age of 69 years undergoing revision hip arthroplasty with Paprosky type 3B acetabular defects reconstructed using PMI between October 2011 and December 2016. A successful result was defined as a postoperative increase in Harris hip score (HHS) of >20 points with a radiographically stable implant (assessed with hip X-rays) and no need for additional acetabular reconstruction. RESULTS: Twelve out of the 13 patients in the study were available for follow-up with mean duration of 50 months. One patient died during the study period due to an unrelated cause. The mean HHS increased from 41 to 82 points. Eleven out of 12 acetabular components were well fixed and pelvic discontinuity healed in all patients. CONCLUSION: Custom triflange PMI is an excellent option for management of complex and extensive acetabular defects with or without pelvic discontinuity.

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Recent studies have shown high early failure rates with Cup Cage constructs in complex revision surgery for Paprosky 3B acetabular defects. As a result, the use of 3D printed custom-made acetabular components has become more common. In this case series, we present two cases that demonstrate the latest advancement in 3D printed implants for severe acetabular bone loss. The follow up was 3 and 7 years. Neither patient has undergone revision surgery of the acetabular component to date. One patient sustained a femoral peri-prosthetic fracture requiring plate fixation. This case study demonstrates that 3D printed implants have excellent intraoperative and immediate postoperative outcomes in revision surgery for severe acetabular bone defects.

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BACKGROUND: Paprosky type IIIa and IIIb acetabular defects remain technically challenging during revision hip arthroplasty. Numerous surgical options exist to counter extensive acetabular bone loss with high postoperative complication and revision rates reported. Our aim was to report comprehensive long-term outcomes of our experience with Trabecular Metal (TM) augments for these difficult cases. METHODS: 38 patients underwent revision total hip arthroplasty at our institution from 2009 to 2014 where a TM augment was used for acetabular deficiency. Prospective radiographic and Patient-Reported Outcome Measures were recorded and analyzed to a mean of 7.3 years (range: 5.4 to 10.8). RESULTS: No patient was excluded or lost to follow-up. Complications included 3 intraoperative fractures, 1 early infection requiring washout with implant retention, 1 early revision due to allograft resorption, and 6 patients who required late repeat revision surgery: 3 for late infection, 2 for aseptic loosening with augment fracture or dislocation, and 1 for recurrent dislocation. The estimated mean implant survivorship was 8.99 years. 93.5% of augments remaining were well osseointegrated while 97% of the acetabular shells were osseointegrated. Hip center of rotation was restored by a mean of 14 mm inferiorly without significant medialization. Short Form-12 (SF-12) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were significantly reduced postoperatively to a level comparable to the average individual. CONCLUSION: This long-term study details our experience of TM augments for the most severe acetabular defects. For such cases, no excellent surgical solution exists; in comparison to alternative methods, we advocate that this technique is reasonably safe and effective.

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BACKGROUND: Cemented primary total hip arthroplasty (THA) associated with acetabular reconstruction (AR) involving impacted bone grafting has been employed successfully in the revision of cavitary defects but the results are reportedly less predictable for segmental defects. The objective of the study is to evaluate the clinical and radiographic results of patients who had presented cavitary, segmental, and combined acetabular defects and received THA/AR involving impacted morselized cancellous bone autografts followed by rigorous postoperative management. METHODS: Clinical outcomes were assessed retrospectively of 154 patients who had been submitted to 169 THA/AR procedures performed by a single surgeon over a 15-year period. The Harris Hip Score system was applied to 103 patients, and the degree of acetabular migration was determined from radiograph images of 91 AR procedures, of which 40 were segmental/combined and 51 were cavitary reconstructions. RESULTS: The frequency of aseptic acetabular loosening was 3% while that of thromboembolic events was 4.1%. According to Harris Hip Score, 87.4% of outcomes were classified as excellent/good after an average follow-up period of 6.4 years irrespective of the type of acetabular defect. Horizontal and/or vertical acetabular migrations and changes in angular tilt were observed in all ARs, although the minor movements detected did not undermine the structural stability of the reconstructions or the functional capacity of patients. CONCLUSION: The described THA/AR technique can be used effectively in the reconstruction of segmental/combined and cavitary acetabular defects. The success of the technique as applied to segmental/combined defects was attributed in part to the rigorous rehabilitation protocol with temporary postoperative weight-bearing restriction.

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Hip implant failure is mainly due to aseptic loosening of the cotyle and is typically accompanied by defects in the acetabular region. Revision surgery aims to repair such defects before implantation by means of reconstruction materials, whose morselized bone graft represents the gold standard. Due to the limited availability of bone tissue, synthetic substitutes are also used. The aim of this study was to evaluate if a synthetic fully resorbable tri-calcium phosphate-based substitute can provide adequate mechanical stability when employed to restore severe, contained defects, in comparison with morselized bone graft. Five cadaveric pelvises were adopted, one side was reconstructed with morselized bone graft and the other with the synthetic substitute, consisting of dense calcium phosphate granules within a collagen matrix. During the biomechanical test, cyclic load packages of increasing magnitude were applied to each specimen until failure. Bone/implant motions were measured through Digital Image Correlation and were expressed in terms of permanent and inducible translations and rotations. The reconstruction types exhibited a similar behavior, consisting of an initial settling trend followed by failure as bone fracture (i.e., no failure of the reconstruction material). When 2.2 Body Weight was applied, the permanent translations were not significantly different between the two reconstructions (p = 0.06-1.0) and were below 1.0 mm. Similarly, the inducible translations did not differ significantly (p = 0.06-1.0) and were below 0.160 mm. Rotations presented the same order of magnitude but were qualitatively different. Overall, the synthetic substitute provided adequate mechanical stability in comparison with morselized bone graft, thus representing a reliable alternative to treat severe, contained acetabular defects.

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BACKGROUND: Acetabular reconstruction with bone impaction grafting in large defects has yielded conflicting results. METHODS: This was a retrospective study of a case series of five patients with a young age (≤50 years) at the time of surgery who had large acetabular defects reconstructed by bone impaction grafting and trabecular metal augments. The mean follow-up was 79 months. We describe the surgical technique in detail. RESULTS: Improvement was significant on the WOMAC and SF-36 scales (p < 0.05). The radiographs taken at the last follow-up examination showed no migration of the polyethylene cup (p = 0.31) or differences in the abduction angle (p = 0.27) compared to the radiographs from the immediate postoperative period. One patient presented two dislocation episodes as a complication. CONCLUSION: The combination of trabecular metal augments with the bone impaction grafting technique in young patients with large acetabular defects provides satisfactory results in the long term and restores the bone stock.

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