Combined trabecular metal acetabular shell and augment for acetabular revision with substantial bone loss

Automated design of bone-preserving, insertable, and shape-matching patient-specific acetabular components

Effective treatment of large acetabular defects remains among the most challenging aspects of revision total hip arthroplasty (THA), due to the deficiency of healthy bone stock and degradation of the support columns. Generic uncemented components, which are favored in primary THA, are often unsuitable in revision cases, where the bone-implant contact may be insufficient for fixation, without significant reaming of the limited residual bone. This study presents a computational design strategy for automatically generating patient-specific implants that simultaneously maximize the bone-implant contact area, and minimize bone reaming while ensuring insertability. These components can be manufactured using the same additive manufacturing methods as porous components and may reduce cost and operating-time, compared to existing patient-specific systems. This study compares the performance of implants generated via the proposed method to optimally fitted hemispherical implants, in terms of the achievable bone-implant contact surface, and the volume of reamed bone. Computer-simulated results based on the reconstruction of a set of 15 severe pelvic defects (Paprosky 2A-3B) suggest that the patient-specific components increase bone-implant contact by 63% (median: 63%; SD: 44%; 95% CI: 52.3%-74.0%; RMSD: 42%), and reduce the volume of reamed bone stock by 97% (median: 98%; SD: 4%; 95% CI: 95.9%-97.4%; RMSD: 3.7%).

Cup-Cage Construct for Treatment of Severe Acetabular Bone Loss in Revision Total Hip Arthroplasty: Clinical and Radiographic Outcomes at a Mean Follow-Up of 7.7 Years

BACKGROUND

Acetabular reconstruction in the context of massive acetabular bone loss is challenging. Achieving implant stability in these situations requires special considerations due to inadequate bone stock around the acetabulum. The cup-cage construct is a treatment option that addresses this issue. This study evaluates survivorship, complications, and functional outcomes using the cup-cage construct.

METHODS

A total of 131 cup-cage implants (129 patients) were identified from our retrospective review of revision total hip arthroplasties from January 2003 to January 2022. Among these cases, 100 (76.3%) were women, the mean age at the time of surgery was 68 years (range, 29 to 92; SD [standard deviation], 12.4), and the mean follow-up was 7.7 years (range, 0.02 to 20.3; SD, 5.1). Kaplan-Meier survivorship analysis was conducted with failure defined as revision surgery and/or failure of the cup-cage reconstruction.

RESULTS

At a mean follow-up of 7.7 years, the cup-cage construct survivorship due to all-cause failure was 83.9% (95% CI [confidence interval]: 77.6 to 90.2) at 5 years with 88 hips at risk, 74.8% (95% CI: 66.2 to 83.4) at 10 years with 38 hips at risk, and 69.8% (95% CI: 59.4 to 80.2) at 15 years with 11 hips at risk. The survivorship due to failure from aseptic loosening was 96.7% (95% CI: 93.6 to 99.8) at 5 years with 88 hips at risk and 95.5% (95% CI: 91.6 to 99.4) at 10 and 15 years with 38 and 11 hips at risk, respectively. The revision rate for aseptic loosening of the cup and/or cage, infection, dislocation, and aseptic loosening of the femoral stem was 5 of 131 (3.8%), 12 of 131 (9.1%), 10 of 131 (7.6%), and 2 of 131 (1.5%). The mean Leg length discrepancy (LLD) improved from 12.2 to 3.9 mm (P < 0.001).

CONCLUSION

The cup-cage construct is a reliable treatment option for the treatment of various acetabular defects. There are favorable survivorship, clinical, and radiographic outcomes, with a satisfactory complication rate.

Total hip arthroplasty with porous tantalum trabecular metal pads in patients with Crowe IV developmental dysplasia of the hip: a midterm followup study

PURPOSE

Crowe IV developmental dysplasia of the hip (DDH) is a catastrophic hip disease. Moreover, obtaining ideal clinical efficacy in conventional total hip arthroplasty (THA) is often difficult. In this study, we aimed to assess the mid-term clinical results of THA with porous tantalum trabecular metal (TM) pads for acetabular reconstruction in the treatment of Crowe IV DDH.

METHODS

A cohort of 28 patients (32 hips) diagnosed with Crowe type IV DDH who underwent acetabular reconstruction during THA using TM pads with scheduled follow-up between 2011 and 2018, were included in this study. Eight cases were men and 24 were women, with a mean age of 48.4 years (range, 36-72 years) and a mean follow-up was 74.3 months (range, 42-132 months). All patients underwent acetabular reconstruction using TM pads and total hip replacement with subtrochanteric osteotomy.

RESULTS

At the final follow-up, 28 hips (87.5%) demonstrated mild or no postoperative limping. The Harris Hip Score improved from 58.4 ± 10.6 preoperatively to 85.6 ± 8.9. The mean pain, stiffness, and function scores on the Western Ontario and McMaster University Osteoarthritis index were 86.5 ± 10.2, 87.3 ± 12.4 and 85.4 ± 11.6 respectively. The mean score of patient satisfaction was 90.4 ± 7.6. Additionally, the SF-12 physical summary score was 41.8 ± 5.6 and the SF-12 mental summary score was 51.6 ± 5.4. TM construct survivorship due to all-cause failure was 90.6% at 5 years with 3 hips at risk, 87.5% at 10 years with 4 hips at risk. The survivorship due to failure from aseptic loosening was 96.9% at 5 years with 1hips at risk and 93.75% at 10 years with 2 hips at risk.

CONCLUSION

This study demonstrated satisfactory mid-term clinical and radiological results with the application of TM pads for acetabular reconstruction combined with THA in patients with Crowe IV DDH.

TRIAL REGISTRATION NUMBER

ChiCTR1800014526, Date: 18/01/2018.

Trabecular Metal Augments During Complex Primary Total Hip Arthroplasty

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.

Evaluation and Management of Acetabular Bone Loss in Revision Total Hip Arthroplasty: A 10-year Update

Acetabular bone loss continues to be one of the most complex and challenging scenarios facing the orthopaedic surgeon. Preoperative planning and classification systems essentially have remained the same, with the Paprosky classification still being the most commonly used. Careful radiological assessment with well-defined criteria can accurately diagnose acetabular bone loss patterns with an associated chronic pelvic discontinuity before surgery. The use of cemented reconstruction techniques has declined, and contemporary practice trends have involved the increasing use of highly porous hemispherical shells in conjunction with modular porous metal augments, which can successfully treat most acetabular revisions. Noncemented treatment options for the management of acetabular bone loss during revision include conventional porous/modular highly porous hemispherical implants, nonmodular highly porous implants with cementable acetabular liners, cup-cage reconstruction, oblong cups, and triflange reconstruction. These options can be combined with modular porous metal augments, structural allografts, impaction grafting, or reconstruction cages. Acetabular distraction is a newer technique for chronic pelvic discontinuity, which is used in conjunction with off-the-shelf revision acetabular shells and modular porous metal augments. This review is an update over the past decade, highlighting studies with mid to long-term follow-up, and presents the advantages, disadvantages, and principles associated with each of the most commonly used reconstructive techniques.

Cup-cage constructs in revision total hip arthroplasty for pelvic discontinuity

Aims

Pelvic discontinuity is a challenging acetabular defect without a consensus on surgical management. Cup-cage reconstruction is an increasingly used treatment strategy. The present study evaluated implant survival, clinical and radiological outcomes, and complications associated with the cup-cage construct.

Methods

We included 53 cup-cage construct (51 patients) implants used for hip revision procedures for pelvic discontinuity between January 2003 and January 2022 in this retrospective review. Mean age at surgery was 71.8 years (50.0 to 92.0; SD 10.3), 43/53 (81.1%) were female, and mean follow-up was 6.4 years (0.02 to 20.0; SD 4.6). Patients were implanted with a Trabecular Metal Revision Shell with either a ZCA cage (n = 12) or a TMARS cage (n = 40, all Zimmer Biomet). Pelvic discontinuity was diagnosed on preoperative radiographs and/or intraoperatively. Kaplan-Meier survival analysis was performed, with failure defined as revision of the cup-cage reconstruction.

Results

The five-year all-cause survival for cup-cage reconstruction was 73.4% (95% confidence interval (CI) 61.4 to 85.4), while the ten- and 15-year survival was 63.7% (95% CI 46.8 to 80.6). Survival due to aseptic loosening was 93.4% (95% CI 86.2 to 100.0) at five, ten, and 15 years. The rate of revision for aseptic loosening, infection, and dislocation was 3/53 (5.7%), 7/53 (13.2%), and 6/53 (11.3%), respectively. The mean leg length discrepancy improved (p < 0.001) preoperatively from a mean of 18.2 mm (0 to 80; SD 15.8) to 7.0 mm (0 to 35; SD 9.8) at latest follow-up. The horizontal and vertical hip centres improved (p < 0.001) preoperatively from a mean of 9.2 cm (5.6 to 17.5; SD 2.3) to 10.1 cm (6.2 to 13.4; SD 2.1) and 9.3 cm (4.7 to 15.8; SD 2.5) to 8.0 cm (3.7 to 12.3; SD 1.7), respectively.

Conclusion

Cup-cage reconstruction provides acceptable outcomes in the management of pelvic discontinuity. One in four constructs undergo revision within five years, most commonly for periprosthetic joint infection, dislocation, or aseptic loosening.

Reconstruction of Paprosky IIIB acetabular defects with porous tantalum shells and augments using the footing technique

Aims

The use of a porous metal shell supported by two augments with the 'footing' technique is one solution to manage Paprosky IIIB acetabular defects in revision total hip arthroplasty. The aim of this study was to assess the medium-term implant survival and radiological and clinical outcomes of this technique.

Methods

We undertook a retrospective, two-centre series of 39 hips in 39 patients (15 male, 24 female) treated with the 'footing' technique for Paprosky IIIB acetabular defects between 2007 and 2020. The median age at the time of surgery was 64.4 years (interquartile range (IQR) 54.4 to 71.0). The median follow-up was 3.9 years (IQR 3.1 to 7.0).

Results

The cumulative medium-term survival of the acetabular construct was 89%. Two hips (5.1%) required further revision due to shell loosening, one hip (2.6%) due to shell dislocation, and one hip (2.6%) due to infection. The median Harris Hip Score improved significantly from 47 points (IQR 41.5 to 54.9) preoperatively to 80 points (IQR 73.5 to 88.6) at the latest follow-up (p < 0.001).

Conclusion

The reconstruction of Paprosky IIIB acetabular defects with porous tantalum shells and two augments using the 'footing' technique showed excellent medium-term results. It is a viable option for treating these challenging defects.

How modular porous metal augments have changed the management of acetabular bone loss at primary or revision total hip arthroplasty

The advent of modular porous metal augments has ushered in a new form of treatment for acetabular bone loss. The function of an augment can be seen as reducing the size of a defect or reconstituting the anterosuperior/posteroinferior columns and/or allowing supplementary fixation. Depending on the function of the augment, the surgeon can decide on the sequence of introduction of the hemispherical shell, before or after the augment. Augments should always, however, be used with cement to form a unit with the acetabular component. Given their versatility, augments also allow the use of a hemispherical shell in a position that restores the centre of rotation and biomechanics of the hip. Progressive shedding or the appearance of metal debris is a particular finding with augments and, with other radiological signs of failure, should be recognized on serial radiographs. Mid- to long-term outcomes in studies reporting the use of augments with hemispherical shells in revision total hip arthroplasty have shown rates of survival of > 90%. However, a higher risk of failure has been reported when augments have been used for patients with chronic pelvic discontinuity.

Survival analysis of 3D printed acetabular implants in revision total hip arthroplasty associated with severe pelvic discontinuities

BACKGROUND

Surgeons still face difficulties when performing aseptic acetabular revision on patients with extensive defects. Advances in three-dimensional printing technology (3DP) have afforded to the surgeons to create a patient-specific implant matching the morphology and topography of the defect.

OBJECTIVE

The aim of the current research was to determine the survivorship in the treatment of acetabular bone defects with pelvic discontinuity (PD).

METHODS

In order to reconstruct Paprosky type III defects with PD, twenty-three patients underwent revision total hip arthroplasty (THA) utilizing 3D-printed implants (Mobelife). The primary outcomes were the implant-associated failure rate correlated with survivorship. As secondary variables, complications and the effect of age, sex, comorbidities, history of infections and the presence of other lower limb arthroplasties on a new revision were analyzed.

RESULTS

Patients were followed out to a mean of 67.22 ± 39.44 months (range, 0.9-127 months). Mobelife implant mean survival was 102.57 ± 9.90 months (95% CI 83.17-121.96). The cohort's implant one-year survival rate was 87%; at ten years, it dropped to 78.3%. There were four revisions: three due to periprosthetic joint infection (PJI) and one case due to aseptic loosening. Cox regression analysis did not identify any variable as predictor of failure.

CONCLUSION

The use of 3DP patient-specific acetabular components has shown encouraging results and it is a viable treatment option for addressing acetabular defects with combined PD in aseptic THA revision.

Does Using Highly Porous Tantalum in Revision Total Hip Arthroplasty Reduce the Rate of Periprosthetic Joint Infection? A Systematic Review and Meta-Analysis

Background

Studies suggest tantalum (Ta) implants may have inherent antibacterial properties. However, there is no consensus regarding the effectiveness of Ta in preventing periprosthetic joint infection (PJI) after revision total hip arthroplasty (rTHA).

Methods

We searched 5 main databases for articles reporting the rate of PJI following rTHA using Ta implants from inception to February 2022. The PJI rates of the Ta group were meta-analyzed, compared with the control group, and represented as relative risks (RRs) in forest plots.

Results

We identified 67 eligible studies (28,414 joints) for assessing the prevalence of PJI following rTHA using Ta implants. Among these studies, only 9 compared the Ta implant group with a control group. The overall PJI rate following rTHA using Ta implants was 2.9% (95% confidence interval [CI]: 2.2%-3.8%), while it was 5.7% (95% CI = 4.1%-7.8%) if only septic revisions were considered. Comparing the Ta and control groups showed a significantly lower PJI rate following all-cause rTHA with an RR = 0.80 (95% CI = 0.65-0.98, P < .05). There was a trend toward lower reinfection rates in the Ta group after rTHA in septic cases, although the difference was not statistically significant (RR = 0.75, 95% CI = 0.44-1.29, P = .30).

Conclusions

Ta implants are associated with a lower PJI rate following all-cause rTHA but not after septic causes. Despite positive results, the clinical significance of Ta still remains unclear since the PJI rate was only reduced by 20%.

Level of Evidence

IV.

Primary Staged Bilateral Total Hip Arthroplasty in a Patient With Short Stature and Hartofilakidis Type I Developmental Dysplasia of the Hip

Syndromes associated with osteochondrodysplasia, short stature, and DDH are rarely reported in the literature. Total hip arthroplasty (THA) in such cases is a complex procedure with a high rate of complications and difficulties. In this case report, we describe the staged bilateral complex primary THA of a patient with the rare occurrence of a syndrome involving osteochondrodysplasia and DDH, highlighting the surgical challenges and importance of the right prosthesis selection.

Forged to heal: The role of metallic cellular solids in bone tissue engineering

Metallic cellular solids, made of biocompatible alloys like titanium, stainless steel, or cobalt-chromium, have gained attention for their mechanical strength, reliability, and biocompatibility. These three-dimensional structures provide support and aid tissue regeneration in orthopedic implants, cardiovascular stents, and other tissue engineering cellular solids. The design and material chemistry of metallic cellular solids play crucial roles in their performance: factors such as porosity, pore size, and surface roughness influence nutrient transport, cell attachment, and mechanical stability, while their microstructure imparts strength, durability and flexibility. Various techniques, including additive manufacturing and conventional fabrication methods, are utilized for producing metallic biomedical cellular solids, each offering distinct advantages and drawbacks that must be considered for optimal design and manufacturing. The combination of mechanical properties and biocompatibility makes metallic cellular solids superior to their ceramic and polymeric counterparts in most load bearing applications, in particular under cyclic fatigue conditions, and more in general in application that require long term reliability. Although challenges remain, such as reducing the production times and the associated costs or increasing the array of available materials, metallic cellular solids showed excellent long-term reliability, with high survival rates even in long term follow-ups.

Treatment of Severe Acetabular Defects With an Antiprotrusio Cage and Trabecular Metal Augments - Clinical and Radiographic Results After a Mean Follow-Up of 6.6 Years

BACKGROUND

Large acetabular bone defects present a serious challenge in revision total hip arthroplasty. The off-label use of antiprotrusio cages in combination with tantalum augments is a promising treatment option in these difficult situations.

METHODS

Between 2008 and 2013, 100 consecutive patients underwent acetabular cup revision with a cage-augment combination in Paprosky 2 and 3 defect types (including pelvic discontinuities). There were 59 patients available for follow-up. The primary endpoint was the explantation of the cage-and-augment construct. The secondary endpoint was acetabular cup revision for any reason. Also, radiographic and functional outcomes (Western Ontario and McMaster Universities Osteoarthritis Index, Harris Hip Score) were evaluated. Implant survival rates were determined using a Kaplan-Meier analysis. The significance level was set at P < .05.

RESULTS

Explantation-free survivorship of the "Cage-and-Augment" system was 91.9% after a mean follow-up of 6.2 years (range, 0 to 12.8). All 6 explantations were due to periprosthetic joint infection (PJI). The overall revision-free implant survival rate was 85.7%, including 6 additional liner revisions due to instability. In addition, 6 early PJI occurred, which were successfully treated with debridement, irrigation, and implant retention. We did observe one patient who had radiographic loosening of the construct without necessity for treatment.

CONCLUSION

The combination of an antiprotrusio cage with tantalum augments is a promising technique in treating large acetabular defects. A major risk of PJI and instability due to large bone and soft tissue defects needs special attention.

Management of Acetabular Bone Loss in Hip Revision Arthroplasty: Case Series Presentation

Considering the increase in life expectancy in the general population and the need for a more active lifestyle, total hip arthroplasty has become an absolutely necessary surgical intervention to maintain these desired results. Along with the evolution of medicine and the increase in the quality and performance of the materials used to make prostheses, the number of patients who benefit from total hip replacement is constantly increasing, and proportionally, the number of patients who will require revision arthroplasty is increasing. Before discussing the need for hip arthroplasty revision, it is necessary to carry out a rigorous clinical and imaging examination for differential diagnosis with other pathologies such as low back pain, the presence of bone or soft tissue tumors, arterial occlusions and claudication, or other systemic diseases. One of the biggest challenges for the orthopedic surgeon in planning a hip revision is the compensation of the remaining acetabular bone defect, either as a result of the osteolysis process or following the process of removing the acetabular component, which in some cases can lead to severe bone loss that is difficult to anticipate in the preoperative planning. In this paper, we will present the short-term results of the use of reinforcement cages fixed with screws and cemented retentive acetabular cups in the case of hip revisions with extensive bone loss. The discussions that derive from the presented series of cases are related to the use of reinforcement cages, which are based on the principle of primary stability obtained with the help of screw fixation but whose risk of osteolysis and implant fixation damage is greater than in the case of implants that also associate biological integration at bone level. The use of reinforcement cages together with the retentive acetabular cup in the case of elderly patients with associated comorbidities, a moderate level of physical activity, and severe muscle insufficiency at the hip level as a result of not using the affected pelvic limb is still a viable solution that allows the patient to walk immediately after the surgery, avoiding the risk of dislocation (especially in patients who use the posterolateral approach) and avoiding morbidity induced by prolonged bed rest.

Partial retention of the acetabular cement mantle in aseptic revision hip arthroplasty: is it a viable option?

INTRODUCTION

Choosing the most appropriate reconstruction method when addressing a cemented cup at hip revision surgery can be a difficult decision. The aim of this study is to look into the practice and results of retaining a well-fixed medial acetabular cement mantle while removing loose superolateral cement. This practice goes against a preconceived principle that if some of the cement is loose it must all be removed. So far, no significant series looking at this is available in the literature.

METHODS

We assessed a cohort of 27 patients in our institution where this practice was carried out and assessed their outcomes clinically and radiographically.

RESULTS

Of the 27 patients, 24 had follow-up ⩾2 years (2.9-17.8, mean 9.3 years). There was 1 subsequent revision for aseptic loosening at 11.9 years, 1 first-stage revision of both stem and cup for infection at 1 month, and 2 patients died without a 2-year review. 2 patients did not have radiographs available for review. 2 of the 22 patients with radiographs available had changes in lucent lines, which were not clinically significant.

CONCLUSION

Based on these results we conclude that retaining well-fixed medial cement during socket revision is a viable reconstruction option in carefully selected cases.

Cemented acetabular components combined with trabecular metal augments provide excellent long-term survivorship for severe acetabular bone loss

BACKGROUND

Acetabular bone loss is a challenging problem for revision hip surgeons. This study aimed to explore long-term outcomes of patients who have undergone cemented acetabular revision in conjunction with trabecular metal augmentation and impaction bone grafting in cases with significant segmental bone loss.

METHODS

All patients who underwent cemented acetabular revision requiring impaction bone grafting and trabecular metal augments with a minimum Paprosky score of 2B and minimum follow up of 5 years were identified. Pre- and postoperative WOMAC scores were compared. An assessment of pre- and postoperative hip centre of rotation was performed and compared to native centre of rotation. Immediate postoperative centre of rotation was then compared to radiographs at latest follow up to measure for migration of acetabular components.

RESULTS

42 patients were identified. Mean age was 53 years old with 7 males and 35 female patients. Mean follow-up was 9.5 years. Preoperative WOMAC score was 30 and there was an increase to 90 (p < 0.01) at latest follow-up. No hips were revised for loosening or infection. There was a mean improvement in centre of rotation of 6.80 mm (CI, 4.57-9.03 mm) which was significant (p < 0.00002). There was no change of position of centre of rotation from immediate postoperative radiographs and those at latest follow up (p = 0.3).

CONCLUSIONS

Cemented acetabular components work well in conjunction with trabecular metal augments and impacted bone grafts in reconstructing complex acetabular defects. Together they provide immediate and long-term component stability, with excellent long-term clinical and radiological outcomes.

Standardized 3D-printed trabecular titanium augment and cup for acetabular bone defects in revision hip arthroplasty: a mid-term follow-up study

BACKGROUND

The aim of this study was to assess the feasibility and outcomes of standardized three-dimensional (3D)-printed trabecular titanium (TT) cups and augments to reconstruct most acetabular defects.

METHODS

We included 58 patients with Paprosky type II and III acetabular bone defects who underwent revision hip arthroplasty between 2015 and 2018. Patients who were revised without 3D-printed augments, and cases who were lost to follow-up and died during follow-up were excluded. Radiographic and clinical outcomes were evaluated. A Kaplan-Meier survivorship curve was generated. The mean follow-up was 64.5 (range 49-84) months.

RESULTS

In total, 48 (82.8%) acetabular revisions were performed using standardized 3D-printed TT cups and augments, and a retrospective review was conducted on 43 revisions. The average position of the vertical center of rotation and leg length discrepancy were significantly decreased from 42.4 ± 9.1 mm and 38.4 ± 10.7 mm to 22.8 ± 3.4 mm and 4.1 ± 3.0 mm, respectively. Non-progressive radiolucent lines were observed in 3 (7.5%) acetabular components with no indications for revision. The mean Harris hip score, Oxford hip score and EuroQol five-dimensional questionnaire score increased from 33.0 ± 10.7, 11.4 ± 3.4 and 0.29 ± 0.09 to 80.3 ± 8.8, 35.8 ± 2.4 and 0.71 ± 0.10, respectively. The revision-free survival rate of the acetabular component was 93.0% (40/43), with a rate of revision for aseptic loosening of 2.3% (1/43).

CONCLUSION

Standardized 3D‑printed TT augments and cups could be used to reconstruct the majority of Paprosky type II and III acetabular defects in revision hip arthroplasty and demonstrated encouraging results at mid-term follow-up.

The Dome Technique for Managing Massive Anterosuperior Medial Acetabular Bone Loss in Revision Total Hip Arthroplasty: Short-Term Outcomes

Purpose

The dome technique is a technique used in performance of revision total hip arthroplasty (THA) involving intraoperative joining of two porous metal acetabular augments to fill a massive anterosuperior medial acetabular bone defect. While excellent outcomes were achieved using this surgical technique in a series of three cases, short-term results have not been reported. We hypothesized that excellent short-term clinical and patient reported outcomes could be achieved with use of the dome technique.

Materials and Methods

A multicenter case series was conducted for evaluation of patients who underwent revision THA using the dome technique for management of Paprosky 3B anterosuperior medial acetabular bone loss from 2013-2019 with a minimum clinical follow-up period of two years. Twelve cases in 12 patients were identified. Baseline demographics, intraoperative variables, surgical outcomes, and patient reported outcomes were acquired.

Results

The implant survivorship was 91% with component failure requiring re-revision in only one patient at a mean follow-up period of 36.2 months (range, 24-72 months). Three patients (25.0%) experienced complications, including re-revision for component failure, inter-prosthetic dual-mobility dissociation, and periprosthetic joint infection. Of seven patients who completed the HOOS, JR (hip disability and osteoarthritis outcome score, joint replacement) survey, five patients showed improvement.

Conclusion

Excellent outcomes can be achieved using the dome technique for management of massive anterosuperior medial acetabular defects in revision THA with survivorship of 91% at a mean follow-up period of three years. Conduct of future studies will be required in order to evaluate mid- to long-term outcomes for this technique.

Revision Total Hip Arthroplasty Utilizing an Acetabular Reinforcement Ring with a Metal Augment: A Minimum Eight-Year Follow-Up Study

Background and Objectives: An acetabular reinforcement ring (ARR) with a structural allograft is conventionally used to treat large acetabular bone defects or discontinuity during revision hip arthroplasty. However, ARR is prone to failure due to bone resorption and lack of incorporation. Here, we investigated the surgical outcomes of the patients who underwent revision total hip arthroplasty (THA) using ARR combined with a metal augment (MA). Materials and Methods: We retrospectively reviewed data from 10 consecutive patients who had a minimum 8-year follow-up after revision hip arthroplasty using ARR with MA in Paprosky type III acetabular defect. We collected patient demographics, surgical details, clinical scores (including Harris Hip Score (HHS)), postoperative complications, and 8-year survival rates. Results: Six male and four female patients were included. The mean age was 64.3 years, and the mean follow-up duration was 104.3 months (96.0-112.0 months). Trauma-related diagnosis was the most common reason for index surgery. Three patients underwent all component revision, and seven underwent cup revision. Six were confirmed as Paprosky type IIIA and four as type IIIB. The mean HHS at the final follow-up was 81.5 (72-91). One patient was diagnosed with prosthetic joint infection at the 3-month follow-up; therefore, the minimum 8-year survival rate with our technique was 90.0% (95% confidence interval, 90.3-118.5%). Conclusions: The satisfactory mid- to long-term results of revision THA suggest that ARR combined with tantalum MA is a viable revision option for treating severe acetabular defects with pelvic discontinuity.

Trabecular titanium implants in complex acetabular revision surgery

INTRODUCTION

Acetabular revision surgery is a surgical challenge, especially when complex bone defects appear. This makes primary fixation and osseointegration of the implants difficult, which conditions the appearance of complications. Trabecular titanium implants attempt to solve these problems.

OBJECTIVES

To evaluate our clinical-radiological results, the survival of the implants and the appearance of mid-term complications in acetabular revision surgery in a series of 37 acetabular replacements with Paprosky type IIIA and IIIB bone defects in which a trabecular titanium Cup-Cage revision implant was used.

MATERIAL AND METHOD

We conducted an observational, descriptive and retrospective study of 37 cases with complex acetabular defects (20 type IIIA and 17 type IIIB, five of them with pelvic discontinuity) in which the acetabular component was replaced by trabecular titanium cups between 2011 and 2019. We analyzed clinical results (pain and functionality) and radiological parameters (restoration of the hip rotation centre and the mobilization of the implants), as well as the appearance of complications.

RESULTS

The mean follow-up was 61 months. We obtained a median improvement of 8 points on the Merlé D'Aubigné-Postel functionality scale and 6 points on the VAS scale of pain perceived by the patient. We recorded two cases of acetabular loosening, one case of dislocation and three surgical wound infections without affecting the implant.

CONCLUSIONS

The use of trabecular titanium Cup-Cage implants could be a valid option in acetabular revision surgery with complex acetabular defects, presenting good clinical and radiological results and in terms of complications and survival of the implants, mainly due to their good primary fixation and subsequent osseointegration.

[Translated article] Trabecular titanium implants in complex acetabular revision surgery

INTRODUCTION

Acetabular revision surgery is a surgical challenge, especially when complex bone defects appear. This makes primary fixation and osseointegration of the implants difficult, which conditions the appearance of complications. Trabecular titanium implants attempt to solve these problems.

OBJECTIVES

To evaluate our clinical-radiological results, the survival of the implants and the appearance of mid-term complications in acetabular revision surgery in a series of 37 acetabular replacements with Paprosky type IIIA and IIIB bone defects in which a trabecular titanium Cup-Cage revision implant was used.

MATERIAL AND METHOD

We conducted an observational, descriptive and retrospective study of 37 cases with complex acetabular defects (20 type IIIA and 17 type IIIB, five of them with pelvic discontinuity) in which the acetabular component was replaced by trabecular titanium cups between 2011 and 2019. We analysed clinical results (pain and functionality) and radiological parameters (restoration of the hip rotation centre and the mobilisation of the implants), as well as the appearance of complications.

RESULTS

The mean follow-up was 61 months. We obtained a median improvement of 8 points on the Merlé D'Aubigné-Postel functionality scale and 6 points on the VAS scale of pain perceived by the patient. We recorded two cases of acetabular loosening, one case of dislocation and three surgical wound infections without affecting the implant.

CONCLUSIONS

The use of trabecular titanium Cup-Cage implants could be a valid option in acetabular revision surgery with complex acetabular defects, presenting good clinical and radiological results and in terms of complications and survival of the implants, mainly due to their good primary fixation and subsequent osseointegration.

Medial wall reconstruction using metal disc augments in revision total hip arthroplasty

PURPOSE

Medial acetabular bone defects are frequently encountered in revision total hip arthroplasty (THA), but few studies have focused on their reconstruction. This study aimed to report the radiographic and clinical results after medial acetabular wall reconstruction using metal disc augments in revision THA.

METHODS

Forty consecutive revision THA cases using metal disc augments for medial acetabular wall reconstruction were identified. Post-operative cup orientation, the centre of rotation (COR), stability of acetabular components and peri-augments osseointegration were measured. The pre-operative and post-operative Harris Hip Score (HHS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) were compared.

RESULTS

The mean post-operative inclination and anteversion were 41.88 ± 6.70° and 16.73 ± 5.35°, respectively. The median vertical and lateral distance between the reconstructed CORs and the anatomic CORs were -3.45 mm (interquartile range [IQR]: -11.30 mm, -0.02 mm) and 3.18 mm (IQR: -0.03 mm, 6.99 mm). Thirty-eight cases completed the minimum two year clinical follow-up, whereas 31 had a minimum two year radiographic follow-up. Acetabular components were radiographically stable with bone ingrowth in 30 cases (30/31, 96.8%) while one case was classified as radiographic failure. Osseointegration around disc augments was observed in 25 of 31 cases (80.6%). The median HHS improved from 33.50 (IQR: 27.50-40.25) pre-operatively to 90.00 (IQR: 86.50-96.25) (p < 0.001), whereas the median WOMAC significantly improved from 38.02 (IQR: 29.17-46.09) to 85.94 (IQR: 79.43-93.75) (p < 0.001).

CONCLUSION

In revision THA with severe medial acetabular bone defect, disc augments could provide favorable cup position and stability, peri-augments osseointegration, with satisfactory clinical scores.

Metal Augments Used in Revision Hip Arthroplasty: A Systematic Review and Single-Arm Meta-Analysis

BACKGROUND

Porous metal augments are used in complex hip arthroplasty; however, few studies have assessed their efficacy and safety. This systematic review analyzed the use of augments in revision hip arthroplasty and summarized the clinical research findings.

METHODS

We used combinations of "revision," "replacement," "arthroplasty," "augment," "acetabular," and "hip" to search PubMed, Web of Science, EMBASE, Cochrane Library databases, and clinical trial registration platform "Clinicaltrials" for relevant literature. The functional score, restoration of hip center of rotation, revision of implants, and complications were analyzed. Patients were divided into 3 subgroups according to the mean follow-up period. Overall, 19 reports involving 647 patients (655 hips) were selected. The mean age at the time of surgery was 63 years (range, 24-106) and the mean follow-up duration was 66 months (range, 11-204).

RESULTS

Harris Hip Score increased from approximately a mean of 40 points preoperatively to a mean of 84 points postoperatively. The vertical distance between hip center of rotation and teardrop was restored from a preoperative distance of 41.9 to 21.7 mm postoperatively. The overall acetabular revision rate was 4.7%, and the incidence of complications was 8.2%. There were significant differences in the reoperation, acetabular revision, and complication rates among the subgroups.

CONCLUSION

Metal augments used in revision hip arthroplasty are a safe and effective treatment option to correct acetabular defects.

[Strategies for cup revision]

Hip arthroplasty revision management can range from simple procedures using standard implants to complex surgical interventions requiring the combined use of revision cups, metal augments, bone grafts, and antiprotrusio cages. The adequate restoration of biomechanics and function of the hip joint with reconstruction of the original center of rotation can be challenging. We present an overview of various available techniques with the associated implant and anchoring strategies and the respective clinical results depending on the acetabular defect situation.

Early outcomes of using custom-made augments in revision total hip arthroplasty

INTRODUCTION

The continuing high demand for revision total hip arthroplasty (RTHA) requires not only additional economic costs, but also the search for new, effective methods to manage the reconstruction of acetabular bone loss. This study focuses on the assessment of the clinical and radiographic outcomes after RTHA using custom-made augments (CMA) in the short-term follow-up period.

MATERIALS AND METHODS

We retrospectively analyzed the results of using CMAs in 19 patients (20 hips). The average follow-up period was 41.3 months. All surgery was performed on defect types III and IV as per the Gross and Saleh classification.

RESULTS

There was a statistically significant difference when comparing the Oxford Hip Score before RTHA of 15.0 (Std. deviation-5.9) and after RTHA of 36.3 (Std. deviation-6.3) (p = 0.01). All implants were radiologically stable. CMA has demonstrated a good ability to restore position of hip centre of rotation (HCOR). In the postoperative period, two patients (2 hips) had dislocations. Only one of two patients underwent re-revision due to dislocation.

CONCLUSION

Treatment of uncontained loss of bone stock in RTHA using CMA shows promising clinical and radiographic results at short-term follow-up period; however, dislocation rate is 10% in this study.

The application of custom-made 3D-printed titanium augments designed through surgical simulation for severe bone defects in complex revision total hip arthroplasty

Background

With the development of radiology and three-dimensional (3D) printing technology, custom-made 3D-printed titanium augments have been more widely used. However, the radiological and clinical outcomes of custom-made augments lack reports. To better understand the clinical effect of using 3D-printed titanium augments and the significance of accurate placement, the aim of this study was to assess the outcomes when using custom-made 3D-printed titanium augments and to validate the idea that surgical simulation should be done before designing custom-made augments.

Methods

A retrospective review was conducted on 31 surgical simulations and revision total hip arthroplasties using custom-made 3D-printed titanium augments. The safe zone, cup position, and hip rotation center were measured on anteroposterior radiographs. Clinical outcomes were assessed with a mean 21.1 months of follow-up.

Results

All patients were positioned within the safe zone, and none of the acetabular cups nor the custom-made augments had any evidence of migration at the latest follow-up. A strong correlation was found between the planned cup position and the postoperative position. The average vertical position of the center of rotation was significantly increased from 3.55 cm to 2.35 cm. The mean Harris Hip Score was increased from 40.81 preoperatively to 65.46 postoperatively. Complications included gait abnormality, groin pain, fracture of the greater trochanter, and partial palsy of the sciatic nerve. However, patient satisfaction reached 92.3%.

Conclusion

Surgical simulations help to design custom-made augments accurately and improve surgical plans. Acetabular components supported with custom-made 3D-printed augments is a useful method to bridge severe bone deficiencies. In this study, both the radiologic results and clinical outcomes were favorable.

Level of evidence

Level 4.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10195-022-00656-5.

A Change in the Classical Order of Setting of Porous Metal Augments with Locked Cups in Hip Revision Surgery: Technical Note and Case Report

Introduction

Reconstruction of acetabular bone defects by the combination of trabecular metal augments and porous cups can be complex when extensive bone loss and poor-quality bone exists. The onset of porous cups with an interlocking mechanism may simplify surgical technique due to its superior initial mechanical stability. We endorse the possibility for a change in the classical order of setting of the augments and the cup.

Methods

We present a technical modification and a series of cases of three patients with Paprosky IIB and IIIA acetabular defects operated with a combination of porous metal augments and a porous cup. In all the three patients, the setting of the cup was done first and secured with locked screws, and then the augments were set in place as a wedge and fixed with screws in a standard fashion.

Results

The postoperative X-ray showed good position of implants with restoration of the center of rotation, and the patients had good recovery. Radiological evaluation in the midterm follow-up did not show mobilization of implants. Discussion. The use of metal porous augments is widely used for severe acetabular defects, being a versatile system to adapt to the different size defects. Nevertheless, its use may be technically demanding and time consuming. It is not infrequent that the setting of the augments conditions the final position of the cup with a possible interference with initial stability and eventually bone ingrowth of the cup. The interlocking mechanism offers an additional biomechanical stability and thus may allow us to place the cup first in the desired position with a less demanding technique.

Conclusion

With the use of locked-screw porous metal cups, the order of setting of implants may be changed in order to obtain a better restoration of the center of rotation and increased host-bone implant contact with a simplified surgical technique.

Reconstruction of Paprosky Type III Acetabular Defects by Three‐Dimensional Printed Porous Augment: Techniques and Clinical Outcomes of 18 Consecutive Cases

Objective

To introduce the surgical technique of reconstruction of Paprosky type III acetabular defects by 3D printed porous augments.

Methods

First, CT scans of pelvis were obtained to establish the 3D reconstruction model of 3D printed porous augment. Then, a nylon pelvis model was printed to simulate operation with the surgeons. At this time, the augment was designed and modified according to the surgeon's suggestions and the 3D printing principles. Eighteen patients with Paprosky type III acetabular defects receiving reconstructive surgery by 3D printed porous augments were included in current study. Their data, including general information, intra‐operative findings, imaging results, functional scores, and complications were retrospectively analyzed.

Results

The mean follow‐up time lasted 33.3 ± 2.0 (24–56) months. The average limb‐length discrepancy (LLD) was 31.7 ± 4.2 (3–59) mm preoperatively, 7.7 ± 1.4 (1–21) mm postoperatively (P < 0.0001), and 7.5 ± 1.2 (0–18) mm at the latest follow‐up. The mean vertical position of hip center of rotation (HCOR) from the interteardrop line changed from preoperative 50.7 ± 3.9 (23.3–75.3) mm to postoperative 22.9 ± 1.9 (10.1–40.3) mm (P < 0.0001), with the latest follow‐up revealing an HCOR of 22.3 ± 1.7 (11.0–40.5) mm. Follow‐up study showed that no hip had radiolucencies and radiological loosening of the acetabular components and augment. The average Harris hip score (HHS) improved from 40.3 ± 4.5 (10.5–71) before operation to 88.4 ± 1.9 (75–97) at the last follow‐up (P < 0.0001). Moreover, follow‐up exhibited that no periprosthetic joint infection, hip dislocation, fracture, and re‐revision occurred.

Conclusion

Surgical treatment of Paprosky type III acetabular defect with 3D printed porous augment was simple, achieved good match between porous augment and the defect bone surface and the acetabular component, ideally restored LLD and HCOR after operation, significantly improved HHS and attained good early clinical outcomes. It is a promising personalized solution for patients with severe acetabular bone defect.

The Diagnosis and Treatment of Acetabular Bone Loss in Revision Hip Arthroplasty: An International Consensus Symposium

Despite growing evidence supporting the evaluation, classification, and treatment of acetabular bone loss in revision hip replacement, advancements have not been systematically incorporated into a single document, and therefore, a comprehensive review of the treatment of severe acetabular bone loss is needed. The Stavros Niarchos Foundation Complex Joint Reconstruction Center at Hospital for Special Surgery held an Acetabular Bone Loss Symposium on June 21, 2019, to answer the following questions: What are the trends, emerging technologies, and areas of future research related to the evaluation and management of acetabular bone loss in revision hip replacement? What constitutes the optimal workup and management strategies for acetabular bone loss? The 36 international experts convened were divided into groups, each assigned to discuss 1 of 4 topics: (1) preoperative planning and postoperative assessment; (2) implant selection, management of osteolysis, and management of massive bone loss; (3) the treatment challenges of pelvic discontinuity, periprosthetic joint infection, instability, and poor bone biology; and (4) the principles of reconstruction and classification of acetabular bone loss. Each group came to consensus, when possible, based on an extensive literature review. This document provides an overview of these 4 areas, the consensus each group arrived at, and directions for future research.

Do trabecular metal cups achieve better results when compared to hemispherical porous titanium cups in acetabular revision surgery?

BACKGROUND

Trabecular metal (TM) cups were introduced in order to achieve better ingrowth and stability of the cup in acetabular revision surgery. As their use has evolved over time, we have queried whether TM cups would improve results in terms of the rate of aseptic loosening when compared to historical uncemented porous titanium cups used in revision surgery for acetabular bone loss in Hospital La Paz (Madrid, Spain).

METHODS

We retrospectively reviewed 197 acetabular revisions performed between 1991 and 2015. Titanium cups were used in 81 cases and TM cups in 116. The mean follow-up was 8.1 years (range 1-15); 12.0 ± 7.8 for titanium group and 5.4 ± 3.1 for TM group. The most common reason for revision was aseptic loosening. A Kaplan-Meier analysis was used to determine the survival of the cup, with radiological failure and re-revision due to aseptic loosening as the endpoints. Cox multivariate regression analyses were performed to assess different risk factors for failure.

RESULTS

1 TM cup and 1 titanium cup were re-revised due to aseptic loosening (p = 0.61). Radiological cup loosening was observed in 4 TM cups and 2 titanium cups (p = 1.0). At 6 years, the probability of not having radiological cup loosening was 97.4% (95% CI, 93.9-100) for the titanium cups and 95.1% for the TM cups (95% CI, 90.1-99.9) (p = 0.59). Another 5 cups were re-revised due to dislocation. Hips with a greater Paprosky defect showed a higher risk of loosening (p < 0.05, hazard risk (HR) 3.04; 95% CI, 0.97-9.54).

CONCLUSIONS

This study shows there was no significant difference in re-revision due to aseptic loosening or radiological loosening between titanium and TM cups in revision surgery for acetabular bone loss. Both types of cups demonstrate excellent results with a low failure rate and minimal complications.

Mid-term outcomes of tantalum cup- a single centre study

Introduction

The cementless acetabular implants are commonly used in primary and revision hip arthroplasty. Reconstruction of acetabulum in case of bone defects can be challenging. The aims of this single center study are to review the mid-term outcomes of porous tantalum cups (TM) and evaluate complications.

Methods

The midterm outcome of a trabecular metal tantalum modular uncemented cup was evaluated in 59 hips in 58 patients. In our group, we had 23 males and 35 females. The mean age was 70.11 years (range, 30 to 87 years). Four patients were lost to follow-up and 13 died during the period without having further surgeries attributed to the hip arthroplasty. The remaining 41 patients (42 revision hip arthroplasties) had complete data available.

Results

The mean follow-up was 87 months, ranging from 24 to 144 months. Standard pelvic anteroposterior (AP) radiographs were used to assess and preoperatively classify acetabular defects as per Paprosky classification. The serial radiographs showed excellent stability, bone opposition and graft incorporation. Four patients had further surgeries. Two of these were due to infection (one superficial and one deep infection). One of the patients had washout and then removal of metal work, the other patient only had a washout and symptoms settled. One patient had vascular compromise and went for surgery to stem the bleeding. One patient had re-revision due to stem loosening and hence required surgery but the revision cup remained stable. We noted a 96% survival at an average of 7.2 years follow-up.

Conclusion

The mid-term results with the trabecular metal cementless cup appeared to be promising in both primary and revision hip arthroplasty, even in the presence of considerable bone loss which requires bone grafting and augments.

Level of evidence

IV.

Primary Stability in Hip Revision Arthroplasty: Comparison of the Stability of Cementless Fixed Augments on a Modular Acetabular Cage System with and without Cranial Straps

The goal of this study is to evaluate the primary stability of a cementless augment-and-modular-cage system with and without the addition of cranial straps in a standardized in vitro setting. As the surrogate parameter for the evaluation of primary stability, the measurement of relative motion between the implant components themselves and the bone will be used. Acetabular revision components with a trabecular titanium augment in combination with a large fourth-generation composite left hemipelvis were assembled. These constructs were divided into two groups with (S) and without cranial straps (nS). A total of 1000 cycles was applied at each of three load levels. Relative movements (RM) between the components were measured. Load levels display a significant effect on the amount of RM at all interfaces except between shell/augment. The group assignment appears to have an effect on RM due to significantly differing means at all interfaces. Between bone/shell RM increased as load increased. NS displayed significantly more RM than S. Between shell/augment RM remained constant as load increased. Between shell/cup S showed more RM than nS while both groups' RM increased with load. We conclude a significant increase of primary stability between the shell and the bone through the addition of cranial straps. Relative motion between components (shell/cup) increases through the addition of cranial straps. A clinical impact of this finding is uncertain and requires further investigation. Finally, the cementless fixation of the augment against the rim-portion of the shell appears stable and compares favorably to prior investigation of different fixation techniques.

Midterm Outcomes After Reconstruction of Superolateral Acetabular Defects Using Flying Buttress Porous Tantalum Augments During Revision Total Hip Arthroplasty

BACKGROUND

Porous tantalum augments are versatile tools in reconstructing complex acetabular defects during revision total hip arthroplasty (THA). This study examines the clinical and radiographic outcomes of porous tantalum augments placed in the type I (flying buttress) configuration at two to 17-year follow-up in the largest cohort to-date in the literature.

METHODS

We retrospectively analyzed 59 consecutive revision THAs involving the use of flying buttress augments between 2003 and 2018. The mean patient age and follow-up duration were 63.9 ± 11.6 years (range, 35-87) and 8 years (range, 2-17), respectively. The Oxford hip score was used to assess clinical outcome. The modified Moore classification was used to assess acetabular augment and shell osseointegration. Kaplan-Meier survival analysis with 95% confidence interval (CI) was used to assess implant survivorship.

RESULTS

The mean Oxford hip score improved from 15.9 ± 6.2 preoperatively to 35.0 ± 6.5 at a mean follow-up of eight years (P < .0001). Radiographic assessment using the modified Moore classification demonstrated five signs of osseointegration in 49 hips (83.1%), four signs in six hips (10.2%), three signs in one hip (1.7%), and one sign in one hip (1.7%). Kaplan-Meier analysis demonstrated ten-year survivorship of 88.9% (95% CI 74.4-95.4) with all-cause revision as end point and 94.3% (95% CI 83.1-98.2) with revision for acetabular aseptic loosening as end point.

CONCLUSION

Treatment of superolateral acetabular defects during revision THA using porous tantalum augments placed in the type I (flying buttress) configuration provides excellent implant survivorship and favorable clinical outcomes at mid-term follow-up.

LEVEL OF EVIDENCE

Therapeutic Level IV.

Pelvic discontinuity: a challenge to overcome

Pelvic discontinuity (PD) has been a considerable challenge for the hip revision arthroplasty surgeon. However, not all PDs are the same. Some occur during primary cup insertion, resembling a fresh periprosthetic fracture that separates the superior and inferior portions of the pelvis, while others are chronic as a result of gradual acetabular bone loss due to osteolysis and/or acetabular implant loosening.

In the past, ORIF, various types of cages, bone grafts and bone cement were utilized with little success. Today, the biomechanics and biology of PD as well as new diagnostic tools and especially a variety of new implants and techniques are available to hip revision surgeons. Ultraporous cups and augments, cup-cage constructs and custom triflange components have revolutionized the treatment of PD when used in various combinations with ORIF and bone grafts. For chronic PD the cup-cage construct is the most popular method of reconstruction with good medium-term results.

Dislocation continues to be the leading cause of failure in all situations, followed by infection. Ultimately, surgeons today have a big enough armamentarium to select the best treatment approach. Case individualization, personal experience and improvisation are the best assets to drive treatment decisions and strategies.

Cite this article: EFORT Open Rev 2021;6:459-471. DOI: 10.1302/2058-5241.6.210022

Long-term results of combined porous tantalum augments and titanium-coated cups for Paprosky type III bone defects in acetabular revision

PURPOSE

The use of porous tantalum augments and titanium-coated cups in primary total hip arthroplasty (THA) with acetabular defects has shown satisfactory outcomes in our centre. The aim of this study was to report the long-term radiological and clinical outcomes of using this combination for Paprosky type III acetabular bone defects in acetabular revision.

PATIENTS AND METHODS

Between January 2007 and January 2015, 45 patients with Paprosky type III acetabular defects underwent acetabular revision using a combination of porous tantalum augments and titanium-coated cups. Among these, 41 patients (41 hips) had complete follow-up. Thirty-one patients had a Paprosky type IIIA defect, and ten patients had a Paprosky type IIIB defect. No patients had pelvic discontinuity. There were 20 males and 21 females with an average age of 63.2 years (range 35-80) at the time of revision surgery.

RESULTS

The mean follow-up was 122.8 months (range 69-165). The Harris Hip Score (HHS) improved significantly from 32.1 points (range 17-58) pre-operatively to 85.3 points (63-98) at the last follow-up. The Short Form-12 (SF-12) and Hip Dysfunction and Osteoarthritis Outcome Score (HOOS) improved significantly for each item at the last follow-up. Two patients had a high hip centre post-operatively. One patient had recurrent dislocation but did not require re-revision. No further revision of the acetabular components was required, and all hips remained stable at the last follow-up with bony ingrowth of the acetabular components according to the criteria of Moore et al. CONCLUSION: The combination of tantalum augments and conventional titanium-coated cups achieved satisfactory long-term radiographic and clinical outcomes for Paprosky type III acetabular bone defects without pelvic discontinuity.

Trabecular Metal Augments for Severe Acetabular Defects in Revision Hip Arthroplasty: A Long-Term Follow-Up

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.

The Dome Technique, an Option for Massive Anterosuperior Medial Acetabular Bone Loss: A Retrospective Case Series

BACKGROUND

Acetabular bone loss in revision total hip arthroplasty can be very challenging even for fellowship-trained surgeons. Although it is uncommon, massive anterosuperior medial defects may be encountered, but treatment options have been limited and better ones are needed.

QUESTIONS/PURPOSES

The primary purpose of this case series is to describe a novel surgical treatment, which we call the dome technique, that can be used to address these challenging defects. The dome technique allows for the systematic reconstruction of massive anterosuperior medial defects of the acetabulum. We sought to illustrate the utility of this procedure in three patients with failed acetabular components and massive anterosuperior medial defects.

METHODS

We undertook a retrospective chart review of three patients who had had Paprosky 3B bone defects and undergone revision total hip arthroplasty by the senior author between 2013 and 2016 using the dome technique. The procedure involved the use of tantalum metal augments pieced together to fill the medial defect and recreate the column support needed for jumbo cup placement. The dome technique is unusual because it allows for intra-operative customization to obtain the proper fit.

RESULTS

At a mean of 23.6 months' follow-up (range, 10 to 37 months), all patients had good functional outcomes; none was in need of further revision.

CONCLUSIONS

In three patients, the dome technique allowed for the anterosuperior column to be recreated by piecing together two porous metal augments to fill the medial bony void and create a stable column for a jumbo cup to be press fit. By recreating the deficient anterosuperior medial bone, the acetabulum can be downsized in a stepwise manner (with further surgery) and reconstructed in a stable fashion. This novel procedure is a unique option for the treatment of this challenging problem.

Surgical Treatment of Pelvic Discontinuity: A Systematic Review and Meta-Analysis

BACKGROUND

Pelvic discontinuity is a rare condition that is treated with a range of implant constructs. However, surgical failure rates are high, and outcome data are inconsistent. It is therefore difficult to gain a clear picture of whether recently developed constructs (antiprotrusio cage [APC], cup-cage, custom triflange, and porous metal) provide better outcomes in terms of mechanical failure and complications in the short to long terms. This study investigated the failure and complication rates associated with cage constructs and porous metal technologies.

METHODS

A systematic review and meta-analysis were performed according to the Meta-analysis Of Observational Studies in Epidemiology (MOOSE) guidelines to evaluate the studies showing pelvic discontinuity in revision total hip arthroplasty. Data retrieved included the intervention performed, length of follow-up, mechanical failure, and other complication rates (dislocation, infection, neurological, loosening, migration). Study quality was assessed with the Methodological Index for Non-Randomized Studies (MINORS) instrument. Pooled mechanical failure and complication rates were calculated using MetaXL 5.3.

RESULTS

None of the included 30 articles (n = 585 hips) were of high quality. The meta-analyses revealed a mechanical failure rate of 14% for all constructs combined. Custom triflange (5%) and cup-cage (7%) had the lowest mechanical failure rates compared with the commonly used APC (25%) and porous metal (12%). The overall other complication rate was 28%, with cup-cage lower at 21% compared with APC (34%) and custom triflange (28%). Long-term evidence investigating both interventions and porous metal technology is limited.

CONCLUSIONS

Mechanical failure rates for cup-cage and custom triflange were lowest. The other complication rate for cup-cage was lower than the pooled average. The study quality was limited, indicating a need for better studies and/or a registry.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Reverse augmentation technique in hip revision arthroplasty: a new strategy for the management of acetabular reconstruction

BACKGROUND

The principle of acetabular total hip revision (THR) is based on acetabular reconstruction and restoration of the center of rotation. The use of augmentation in high cranial acetabular defects combined with a cementless revision shell was studied sufficiently. This study aimed to report a case with the use of an augment inside a cementless revision shell as a reverse augmentation technique.

METHODS

We describe the case of an 86-year-old female patient with a massive acetabular defect during second revision for total hip arthroplasty (THA). Two problems occurred: (1) a fixed cemented stem with a nonmodular head size of 33 mm and (2) a high acetabular defect with an elevated rotation center.

RESULTS

With the distraction technique, allograft filling was used to reconstruct the acetabular defect. A cementless revision shell (REDAPT, Smith and Nephew) with a size of 78 mm was used to stabilize the defect. Locking screws placed cranially and distally were used to stabilize the cup for secondary osseointegration. An augment was placed inside the cup to reconstruct the rotation center. A customized polyethylene liner (outer diameter, 54 mm/inner diameter, 33 mm) was positioned below the augment in the revision cup to reconstruct the center of rotation. An 18-month postoperative X-ray analysis showed a stable construct with full secondary osseointegration.

CONCLUSION

This is the first report of an augment used for a reverse technique inside a cementless shell to restore the center of rotation with the use of a customized polyethylene liner. This might be a reliable option for reconstruction of the center of rotation in large cementless revision cups in acetabular Paprosky type III defects. This technical note shows the possibility of using an augment as a reverse technique in a cementless revision cup.

Reconstruction options and outcomes for acetabular bone loss in revision hip arthroplasty

Revision total hip arthroplasty in the setting of acetabular bone loss is a challenging procedure and requires a solid understanding of current acetabular reconstruction options. Despite major developments in the field of revision hip surgery in recent decades, reconstruction of acetabular defects remains a major problem in order to achieve primary stability and durable fixation without sacrificing additional bone stock. Although there are several ways to classify acetabular bone defects, the Paprosky classification system is the most commonly used to describe the defects and guide treatment strategy. An understanding of the bone defects associated with detailed pre-operative assessment and planning are essential elements in order to achieve satisfactory outcomes. Multiple acetabular reconstructive options are currently available including impaction bone grafting with metal mesh, reinforcement rings and antiprotrusio cage, structural allografts, cementless hemispherical cups, extra-large "jumbo cups", oblong cups, modular porous metal augments, cup-cage constructs, custom- made triflange cups, and acetabular distraction. To date, debate continues as to which technique is most effective due to the lack of long-term studies of modern reconstruction systems. Further long-term studies are necessary to assess the longevity of the different implants. The purpose of this study was to review the current literature and provide a comprehensive understanding of the available reconstruction options with their clinical outcomes.

Cup-Cage Solution for Massive Acetabular Defects: A Systematic Review and Meta-Analysis

Our systematic review compiled multiple studies and evaluated survivorship and clinical outcomes of cup‐cage construct usage in the management of massive acetabular bone defects. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses (PRISMA) guidelines. Various combinations of “acetabular”, “pelvis”, “cup cage” and their corresponding synonyms were used to search relevant articles in the Cochrane, EMBASE, and PubMed databases. Basic information of the functional scores, implant revision rate, and complication rate were selected as outcomes for analysis. Finally, a total of 11 articles published between 1999 and 2019 were selected, which include 232 patients with an average age of 68.5 years (range, 30–90). The mean follow‐up period was 48.85 months (range, 1–140). Our study shows that the cup‐cage construct has a good clinical outcome with a low revision rate and a low complication rate. Improved clinical outcomes of cup‐cage constructs were seen with a revision rate of 8% and an all‐cause complication rate of 20%. The most commonly reported complication was dislocation, followed by aseptic loosening, infection, and nerve injuries. In summary, it is a promising method for managing large acetabular bone defects in total hip revision.

Reverse reaming distraction for acetabular reconstruction of chronic pelvic discontinuity

Background

The acetabular distraction technique demonstrates encouraging radiographic and clinical outcomes in treating chronic pelvic discontinuity. The aim of this study is to describe a modified distraction technique and to show our results.

Methods

This study identified 12 cases of chronic pelvic discontinuity undergoing primary or revision total hip arthroplasty (THA) with the technique of reverse reaming distraction between July 2015 and November 2018. All 12 patients had a minimum follow-up of 12 months. Radiographs were reviewed to inspect for component loosening. Clinical assessment included the Harris hip score (HHS) and an ambulatory scoring system.

Results

At the time of final follow-up, no patient was revised. One patient had up to 1 cm migration of the cup in a horizontal or vertical direction and more than 20° change in the abduction angle but was asymptomatic. In the remaining 11 patients, no migration of the component was detected. Both the HHS and ambulatory score showed improvement in all patients. There were no perioperative complications. No postoperative dislocation occurred.

Conclusions

Reverse reaming distraction is a feasible technique in treatment of chronic pelvic discontinuity, with encouraging results at early term. However, ongoing follow-up is required to determine the long-term prognosis in patients receiving this technique.

Comparison of the Primary Stability of Porous Tantalum and Titanium Acetabular Revision Constructs

Adequate primary stability of the acetabular revision construct is necessary for long-term implant survival. The difference in primary stability between tantalum and titanium components is unclear. Six composite hemipelvises with an acetabular defect were implanted with a tantalum augment and cup, using cement fixation between cup and augment. Relative motion was measured at cup/bone, cup/augment and bone/augment interfaces at three load levels; the results were compared to the relative motion measured at the same interfaces of a titanium cup/augment construct of identical dimensions, also implanted into composite bone. The implants showed little relative motion at all load levels between the augment and cup. At the bone/augment and bone/cup interfaces the titanium implants showed less relative motion than tantalum at 30% load (p < 0.001), but more relative motion at 50% (p = n.s.) and 100% (p < 0001) load. The load did not have a significant effect at the augment/cup interface (p = 0.086); it did have a significant effect on relative motion of both implant materials at bone/cup and bone/augment interfaces (p < 0.001). All interfaces of both constructs displayed relative motion that should permit osseointegration. Tantalum, however, may provide a greater degree of primary stability at higher loads than titanium. The clinical implication is yet to be seen

Tantalum implants for posterior lumbar interbody fusion: A safe method at medium-term follow-up?

INTRODUCTION

Intervertebral implants increase stability and improve results in lumbar interbody fusion (LIF). The aim of the present study was to assess clinical and radiological results of posterior lumbar interbody fusion (PLIF) using a tantalum intervertebral implant without associated interbody bone graft.

MATERIEL AND METHODS

A single-center retrospective study included 52 cases of single-level PLIF, using 2 tantalum intervertebral cages, without interbody bone graft: 42 for degenerative disc disease, 10 for isthmic spondylolisthesis. Minimum follow-up was 2 years. Clinical assessment used a visual analog (pain) scale (VAS), the Oswestry Disability Index (ODI) and the Roland Morris (RM) scale. Tantalum osseointegration and intersegment mobility were assessed on static and dynamic X-ray.

RESULTS

Forty-nine patients were included, with a mean 55months' follow-up (range, 25-74months). VAS, ODI and RM scores showed significant improvement at last-follow-up, at 4, 30 and 28 points respectively. There was no mechanical failure on static X-ray; all patients had less than 5° mobility on dynamic X-ray at last follow-up.

DISCUSSION

PLIF with tantalum intervertebral implant without interbody bone graft provided satisfactory clinical and radiological results at medium-term follow-up. The present findings showed reliable primary stability and osseointegration of the tantalum implant.

LEVEL OF EVIDENCE

IV.

Role of MRI in the assessment of interbody fusion with tantalum intervertebral implant

INTRODUCTION

Radiologic assessment of interbody fusion (IF) is controversial; thin-slice CT is the present gold standard despite artifacts due to the metal implant that hinder interpretation. The present study aimed to assess the contribution of MRI in IF assessment after instrumented posterior lumbar interbody fusion (PLIF) using tantalum intervertebral implants. The study hypothesis was that fusion following PLIF can be assessed on MRI.

MATERIALS AND METHOD

A single-center retrospective study included 52 single-level PLIF procedures (42 for degenerative disc disease and 10 for isthmic spondylolisthesis) using 2 tantalum intervertebral cages without interbody bone graft. Fusion was assessed at 1 year on static and dynamic X-ray and on MRI with a dedicated protocol. Two senior osteoarticular radiologists screened frontal and sagittal MRI slices for continuous cancellous interbody bridges. Consolidation was considered acquired (grade I) in case of continuous bridges on at least 2 successive frontal or sagittal slices, possible (grade II) in case of continuous bridge on just 1 slice, or absent (grade III) in case of no or discontinuous bridge.

RESULTS

Forty-eight patients were included, with a mean 55 months' follow-up (range, 25-74 months). There were no hardware failures. Intervertebral mobility on dynamic X-ray was systematically less than 5°. Fusion on MRI was grade I in 71% of cases, grade II in 8% and grade III in 21%. Interobserver agreement was 100% on X-ray and 81% on MRI, with kappa coefficient=0.56 (range, 0.35-0.77).

DISCUSSION

Tantalum implants without bone autograft enabled satisfactory standard radiographic study. MRI provided imperfect assessment of fusion, being contributive only in case of positive findings (71% in the present study); when no bridge is detected on MRI, no conclusion can be drawn. Progress in CT to reduce artifacts may improve fusion assessment, unless bone integration on both sides of the implant is considered to be sufficient for interbody continuity, without a continuous bone bridge between endplates being a requirement.

LEVEL OF EVIDENCE

IV.

Three-dimensional-printing Technology in Hip and Pelvic Surgery: Current Landscape

The use of three-dimensional (3D) printing is becoming more common, including in the field of orthopaedic surgery. There are currently four primary clinical applications for 3D-printing in hip and pelvic surgeries: (i) 3D-printed anatomical models for planning and surgery simulation, (ii) patient-specific instruments (PSI), (iii) generation of prostheses with 3D-additive manufacturing, and (iv) custom 3D-printed prostheses. Simulation surgery using a 3D-printed bone model allows surgeons to develop better surgical approaches, test the feasibility of procedures and determine optimal location and size for a prosthesis. PSI will help inform accurate bone cuts and prosthesis placement during surgery. Using 3D-additive manufacturing, especially with a trabecular pattern, is possible to produce a prosthesis mechanically stable and biocompatible prosthesis capable of promoting osseointergration. Custom implants are useful in patients with massive acetabular bone loss or periacetabular malignant bone tumors as they may improve the fit between implants and patient-specific anatomy. 3D-printing technology can improve surgical efficiency, shorten operation times and reduce exposure to radiation. This technology also offers new potential for treating complex hip joint diseases. Orthopaedic surgeons should develop guidelines to outline the most effective uses of 3D-printing technology to maximize patient benefits.

An alternative treatment option for Paprosky Type IIIb acetabular defect using multiple tantalum wedges - A case report

The treatment of severe acetabular defects in revision total hip arthroplasty (Paprosky type IIIa and IIIb) is demanding and choosing the appropriate surgical technique remains controversial. The introduction of trabecular metal augments has led to a variety of new treatment options. The authors present a case of a Paprosky Type IIIb acetabular defect due to eight subsequent revisions of the left hip. The patient was treated with an alternative treatment option using multiple tantalum wedges. Anatomical reconstruction was achieved and at 12 months follow-up, the patient was pain free and was able to walk without walking aids.

Cup-cage construct for massive acetabular defect in revision hip arthroplasty- A case series with medium to long-term follow-up

OBJECTIVE

Cup-cage reconstruction has emerged as a possible solution for managing massive acetabular defects with a few existing studies reporting encouraging results at mid-term follow-up. We present our experience with this unitised construct.

METHOD

Six patients (7 hips) with a mean age of 76 years (73-81) were revised due to catastrophic aseptic failure of a primary cup implanted 10-19 years previously, having a Paprosky type 3B acetabular defect.

RESULTS

At a mean follow-up of 72 months (63-140) no cases have required re-revision. Oxford Hip Scores improved from an average of 8 (1-17) preoperatively to an average of 36 (18-45) at the last follow-up. WOMAC scores preoperatively averaged 76 (49-96) and postoperatively averaged 26.5 points (0-69) at the last follow-up. SF-12 scores improved in both components. One patient showed non-progressive osteolysis around the ischial flange and one had less than 5 mm migration of the construct. One patient died of unrelated causes.

CONCLUSION

Our study presents one of the longest follow-up of cup-cage construct and supports the previously reported good results; it encourages the use of this construct in reconstruction of massive acetabular defect, with or without pelvic discontinuity.

Three-dimensional technology assisted trabecular metal cup and augments positioning in revision total hip arthroplasty with complex acetabular defects

BACKGROUND

Revision total hip arthroplasty (THA) with large acetabular defect remains a challenge. Though trabecular metal (TM) cup and augments have been introduced in defect reconstruction with good result, the accurate positioning of implant is important to avoid complications. Therefore, we aimed to evaluate the usefulness of three-dimensional (3D) simulation and 3D model in assisting implant positioning during complex revision THA.

METHODS

Sixteen patients (18 hips) who underwent revision THA with a Paprosky type III acetabular defect were analyzed retrospectively. Placement of acetabular cup and TM augments was simulated with 3D simulation software and 3D model preoperatively. Cup anteversion, abduction angle, and hip center were measured in each case preoperatively and postoperatively. Primary outcome was the percentage of outliers according to Lewinnek safe zone and Harris hip score (HHS). Secondary outcome was the correlation between the 3D planned and the postoperative value.

RESULTS

The percentage of outliers was significantly corrected from 77.78% (14/18) preoperatively to 38.88% (7/18) postoperatively (p = 0.04). There was a significant correlation between mean planned cup anteversion and postoperative value (13.39 vs 11.99, r = 0.894; p < 0.001). There was a significant correlation between mean planned abduction and postoperative value (42.67 vs 44.91, r = 0.921, p < 0.001). The number of planned and used augments was the same in all the cases. In 15 cases (83.33%), the size of planned and used TM augments was the same. The HHS was significantly improved at final follow-up (80.94 vs 27.50, p < 0.001). No cases presented dislocation or radiological signs of loosening.

CONCLUSION

Preoperative 3D simulation and model were considered the useful method to assist implant positioning in revision THA with complex acetabular defect, with moderate to high accuracy and satisfied clinical outcome.