High rate of failure of impaction grafting in large acetabular defects

Long-term outcomes of acetabular impaction grafting with cemented cups and trabecular metal for revision hip arthroplasty: a follow-up study

INTRODUCTION

Revision hip arthroplasty in the presence of complex acetabular deficiencies is challenging. Cement, allograft, reconstruction rings and porous trabecular metal now provide versatile options for acetabular fixation and restoration of acetabular offset. We compare acetabular impaction bone grafting (AIBG) and trabecular metal (TM) cups at long-term follow-up.

METHODS

53 patients who underwent revision hip arthroplasty were retrospectively reviewed from local joint registry data. 36 patients were revised using AIBG and 17 with TM. Median clinical follow-up was 9.57 (2.46-18.72) years and 9.65 (7.22-12.46) years, respectively. 82% of the TM group and 63% of the AIBG group were ⩾ Paprosky 2C. Re-revision was considered failure. Radiographs demonstrating 5 mm of femoral head migration and 5° of acetabular component inclination change were considered loose.

RESULTS

Patients receiving AIBG were younger (68 vs. 74 years) with a longer interval from initial arthroplasty to revision (17 vs. 13 years). Revisions in both groups were indicated most commonly for failed cementing (AIBG 88.9% vs. TM 70.5%). No TM reconstructions underwent re-revision, with only 1 failing at 6.3 years, compared with 9 AIBG re-revisions. When revising for sepsis, 33% of AIBG revisions failed.

CONCLUSIONS

AIBG demonstrated high failure rates at long-term follow-up when compared to TM constructs. We recommend the use of AIBG in small cavitary defects only. We strongly advise against its use in the setting of significant bony defects and for prosthetic joint infection.

A Registry Study On Acetabular Revisions Using Jumbo Cups: Do We Really Need A More Complex Revision Strategy?

BACKGROUND

The increasing global performance of total hip arthroplasty (THA) has led to a corresponding rise in revision surgeries, primarily due to cup implant failure, with aseptic loosening and periprosthetic infection being common causes. Various techniques and implants, including jumbo cups (JCs), are employed to manage residual bone loss post-cup removal, facilitating enhanced surface area for improved host bone contact and biological osteointegration. The purpose of the present study was to determine the outcomes of acetabular revision arthroplasty using JC implants over a 20-year follow-up period by reporting overall survival, complications leading to re-revision surgery, and surgical strategy in the case of re-revision.

METHODS

A cohort study based on a large regional registry was conducted, examining revision THA surgeries utilizing JCs between 2000 and 2020. The study included all the revision acetabular procedures performed with cementless JCs, identified with a diameter ≥ 62 mm in women or ≥ 66 mm in men. All iliac fixation cups were excluded. Data on demographics, revision surgery indications, components, fixation types, causes of failure, and reintervention strategies were collected and analyzed. A total of 541 JCs implanted from January 2000 to December 2020 were evaluated. The most common revision indications were "cup aseptic loosening" (54.5%) and "total aseptic loosening," which included both the cup and stem (32%).

RESULTS

Jumbo cup survival rates were 92.5% at 5 years, 85.8% at 10 years, and 81.5% at 15 years. Among the 70 failures, the main causes were "cup aseptic loosening" (40%), "total aseptic loosening" (17.1%), and "septic loosening" (12.8%). Revisions primarily involved acetabular cup revision surgery (54 cases), component explantation (11 cases), or insert/head revision (5 cases).

CONCLUSIONS

This registry-based study of JCs in revision THA demonstrates excellent 15-year survival rates and acceptable failure rates. It supports JCs as a viable option, offering relative surgical simplicity compared to alternatives like anti-protrusion cages, bone grafts, and augments.

Cost-effectiveness of decellularised bone allograft compared with fresh-frozen bone allograft for acetabular impaction bone grafting during a revision hip arthroplasty in the UK

OBJECTIVES

Fresh-frozen allograft is the gold-standard bone graft material used during revision hip arthroplasty. However, new technology has been developed to manufacture decellularised bone with potentially better graft incorporation. As these grafts cost more to manufacture, the aim of this cost-effectiveness study was to estimate whether the potential health benefit of decellularised bone allograft outweighs their increased cost.

STUDY DESIGN

A Markov model was constructed to estimate the costs and the quality-adjusted life years of impaction bone grafting during a revision hip arthroplasty.

SETTING

This study took the perspective of the National Health Service in the UK.

PARTICIPANTS

The Markov model includes patients undergoing a revision hip arthroplasty in the UK.

INTERVENTION

Impaction bone grafting during a revision hip arthroplasty using either decellularised bone allograft or fresh-frozen allograft.

MEASURES

Outcome measures included: total costs and quality-adjusted life years of both interventions over the lifetime of the model; and incremental cost-effectiveness ratios for both graft types, using base case parameters, univariate sensitivity analysis and probabilistic analysis.

RESULTS

The incremental cost-effectiveness ratio for the base case model was found to be £270 059 per quality-adjusted life year. Univariate sensitivity analysis found that changing the discount rate, the decellularised bone graft cost, age of the patient cohort and the revision rate all had a significant effect on the incremental cost-effectiveness ratio.

CONCLUSIONS

As there are no clinical studies of impaction bone grafting using a decellularised bone allograft, there is a high level of uncertainty around the costs of producing a decellularised bone allograft and the potential health benefits. However, if a decellularised bone graft was manufactured for £2887 and lowered the re-revision rate to less than 64 cases per year per 10 000 revision patients, then it would most likely be cost-effective compared with fresh-frozen allograft.

Custom-made implants for massive acetabular bone loss: accuracy with CT assessment

BACKGROUND

Custom-made implants are a valid option in revision total hip arthroplasty to address massive acetabular bone loss. The aim of this study was to assess the accuracy of custom-made acetabular implants between preoperative planning and postoperative positioning using CT scans.

METHODS

In a retrospective analysis, three patients who underwent an acetabular custom-made prosthesis were identified. The custom-made designs were planned through 3D CT analysis considering surgical points of attention. The accuracy of intended implants positioning was assessed by comparing pre- and postoperative CT analyzing the center of rotation (CoR), anteversion, inclination, screws, and implant surface in contact with the bone.

RESULTS

The three cases presented satisfactory accuracy in positioning. A malpositioning in the third case was observed due to the posterization of the CoR of the implant of more than 10 mm. The other CoR vectors considered in the third patient and all vectors in the other two cases fall within 10 mm. All the cases were positioned with a difference of less than 10° of anteversion and inclination with respect to the planning.

CONCLUSIONS

The current case series revealed promising accuracy in the positioning of custom-made acetabular prosthesis comparing the planned implant in preoperative CT with postoperative CT.

Impaction bone grafting for contained acetabular defects in total hip arthroplasty

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.

Osseointegration and Success in Hip Arthroplasty Acetabular Revision Using Structured Homologous Graft: Average 9.6 Years Follow-up

Objective  To evaluate the clinical and radiographic results and survival of the acetabular revision surgery of total hip arthroplasty with cemented implant without the use of reinforcement ring, associated with structural homologous bone grafting. Methods  A total of 40 patients (44 hips) operated from 1995 to 2015 were retrospectively analyzed. Radiographs were evaluated according to the classification of the acetabular bone defect, graft shape, and the presence of osseointegration. Cases were considered as failures when the migration of the implant was > 5 mm in any direction, and/or the progression of radiolucency lines around the acetabular component were > 2 mm. We verified the association of radiographic findings with cases of failure using statistical tests and analyzed survival using the Kaplan-Meier curve. Results  Of the 44 hips, 45.5% of the acetabular defects were Paprosky type 3A and 50% were 3B. In 65% of the hips, the graft configuration was classified as Prieto type 1 and in 31% as type 2. No radiographic evidence of osseointegration was observed in 13.6% of the cases. We observed 9 (20.5%) reconstruction failures. A correlation was observed between reconstruction failure and the absence of radiographic signs of graft osseointegration. Conclusion We observed good clinic and radiographic results, with survival of 79.54% in a mean follow-up of 9.65 years. Also, there was an association between absence of radiographic signs of osseointegration of the structural graft and failure in this series of patients with large bone defects. The failures did not correlate with the severity of the acetabular bone defect, thickness, or graft configuration.

THA in patients with neglected acetabular fractures

Introduction: Total hip arthroplasty (THA) outcomes in patients with neglected acetabular fractures are less favourable compared to THA for osteoarthritis or inflammatory arthritis. These poorer clinical outcomes are largely due to an unexpected bone deficiency, and the procedure is more time-consuming and complicated for cases that require acetabular reconstruction and bone grafting. The clinical outcomes of THA in neglected acetabular fractures are not often studied. Methods: This study is a retrospective single surgeon series of THA for 51 neglected acetabular fractures in 49 patients treated with THA alone, open reduction and internal fixation with THA, or acetabular defect reconstruction THA. Our series aims to focus on the surgical technique and describe the functional and radiological outcomes of neglected acetabular fractures treated with different THA approaches by a single surgeon. Results: Using the Harris Hip score at the mean long-term follow-up, there was a clear improvement in 90% of patients in the present study. The long-term results are encouraging in terms of clinical improvement, radiographic restoration of acetabular bone stock, and the centre of restoration. Discussion: The series shows that with proper planning and reconstruction using structural bone grafting techniques, a neglected fracture-dislocation with loss of structural support can be satisfactorily treated using primary components alone. Bony reconstruction and use of primary cementless components ensure long-term survival and preserve bone stock for an easier revision of THA, if necessary, in the future.

Extended Ischiopubic Fixation Using Porous Metal Augments in Cementless Acetabular Reconstruction during Revision Total Hip Arthroplasty

Objectives

The aims of this study were to introduce the definition, indication, and surgical technique of extended ischiopubic fixation (EIF) and to investigate the early clinical, radiographic results and complications of hips revised with EIF.

Methods

Patients who underwent revision THA utilizing the technique of EIF which was defined as securing the porous metal augment >5 mm deep into the ischium and/or pubic ramus to gain adequate mechanical support and fresh host bone for bony ingrowth in a single institution from February 2015 to February 2020 were retrospectively reviewed. After applying the inclusion and exclusion criteria, a total of 30 hips (28 patients) were eligible for the study and were enrolled. Four patients were lost to follow‐up postoperatively. The data of the remaining 24 patients (26 hips) were analyzed. The patients' clinical results were assessed using of the Harris Hip Score and any complications including postoperative periprosthetic joint infection, intraoperative fracture, postoperative periprosthetic fracture, dislocation, nerve palsy, hematoma or wound complication were documented. The radiographic results were assessed with the construct stability, the position of the center of rotation, and cup orientation.

Results

The median age of these 25 patients was 62.00 (interquartile: 54.25–68.25) years, with a median body mass index (BMI) of 22.60 kg/m² (interquartile: 21.49–25.12 kg/m²). A total of 12 (48%) patients were female. At a median duration of follow‐up of 49.16 months, 20 (80%) patients rated their satisfaction level as “very satisfied,” five (20%) were “satisfied.” The median HHS improved from 36.00 (interquartile range: 31.25–49.75) preoperatively to 81.00 (interquartile range: 74.75–88.25) at the most recent follow‐up (p < 0.001). No complications such as periprosthetic joint infection, intraoperative fracture, periprosthetic fracture, dislocation, nerve palsy, hematoma, or wound complication were identified. All constructs were considered to have obtained stable fixation. The median vertical and horizontal distance between the latest postoperative centers of rotation to the anatomic center of rotation improved from 13.62 and 8.68 mm preoperatively to 4.42 and 4.19 mm at final follow‐up (p < 0.001).

Conclusions

Early follow‐up of patients reconstructed with porous metal augments using the EIF technique demonstrated satisfactory clinical results with no particular complications, stable fixation, and restoration of the center of rotation.

Mid-term results in revision hip arthroplasty with impaction bone grafted cup reconstruction for acetabular defects

Acetabular defects are a challenging condition for surgeons in revision THA. A crucial aim is an anatomical restoration of the centre of rotation (COR) through grafts. The aim of this study was to determine the cup survival after biological restoration of acetabular defects in THA and the effect of Paprosky classification, age, BMI, and number of previous operations on cup survival. Retrospectively patients with a cup exchange and an impaction of cortico-cancellous or bulk grafts between 2009 and 2012 were included with a follow up with a minimum of 5 year. Implant failure was defined as radiographic loosening or explantation of the cup. The acetabular defect situation was classified to Paprosky. 82 patients (58 female 70.7%) were included. 26 patients were not available to contact. 56 patients (40 female 71.4%) remained for survival analysis with mean age of 75.6 ± 8 years. Survival of the cup after 5 years was 90% and after 7.8 years 88%. There was no difference in survival concerning defect classification, type of implant or graft, age, BMI, and number of previous operations. Patients on the follow up reached an HHS of 67.4 ± 19, a WOMAC Score of 33.4 ± 25.4 points and an unsatisfactory result in the SF-36. Impaction bone grafting of acetabular defects is a good option with satisfactory biomechanical results and survival for small defects. Predictive factors for cup survival could not be clarified in our study. So, the correct indication, knowing the limits of the methods and the correct choice of implant allow a defect-oriented approach and are decisive for the success of the operation.

Trabecular metal augments in severe malignancy-associated acetabular bone loss

INTRODUCTION

Acetabular reconstruction is a challenging problem in orthopaedic oncology, especially in extended defects (Paprosky Type 3A and Type 3B). In revision total hip arthroplasty (THA), 1 option is trabecular metal (TM) augments with a porous metal acetabular component. This study evaluated the use of TM augments in periacetabular malignant bone disease.

METHODS

15 patients were identified from our institutional database from 2000 to 2020 with either Paprosky Type 3A or Type 3B acetabular bone loss due to periacetabular malignancies that underwent at least 1 complex THA reconstruction with TM augments. Postoperative complications were documented, and clinical and radiographic outcomes were analysed. Radiological loosening or revision of the acetabular component were defined as endpoints.

RESULTS

There were 7 primary and 8 metastatic cancer patients. 5 were Type 3A and 10 were Type 3B defects after tumour resection. The average follow-up time was 23.8 (range 1.5-47) months. 1 patient required revision for acetabular component loosening after 7 months from the initial implantation. An additional 4 patients required surgical intervention for infection, they had stable TM augments at latest follow-up.

CONCLUSION

TM augments with a porous metal acetabular component may be an alternative to the traditional cemented constructs.

Uncemented Cups and Impaction Bone Grafting for Acetabular Bone Loss in Revision Hip Arthroplasty: A Review of Rationale, Indications, and Outcomes

Total hip arthroplasty (THA) is increasingly performed in young patients and the number of revisions is estimated to rise over time. Acetabular osteolysis and bone loss are frequently encountered during revision and may be classified and treated in different ways. Impaction bone grafting (IBG) with morselized allograft offers a viable option. IBG was introduced over 40 years ago in combination with cemented cups, and is also used with uncemented cups. The impacted bone chips act as a void filler to restore bone stock; once incorporated they are substituted by host bone. Surgery entails assessment of the defect, acetabular preparation, preparation of the morselized graft, impaction of the graft, and cup implantation. Satisfactory medium- and long-term results have now been reported in most studies. With the advent of high-porosity cups, indications have been extended, enhancing the potential of IBG, in which primary stability of the cup to the host bone is essential for a successful procedure. Synthetic bone substitutes have also been used in combination with allogenic grafts and may extend the original technique for which long-term studies are warranted.

Acetabular impaction grafting with mesh for acetabular bone defects: a systematic review

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.

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.

A Review and Description of Acetabular Impaction Bone Grafting: Updating the Traditional Technique

Restoring acetabular bone loss in revision hip arthroplasty is a major challenge for the orthopaedic surgeon. This paper discusses the traditional cemented technique of impaction bone grafting as applied to the acetabulum, as well as the evolution of the technique to employ uncemented implants. Some of the recent published literature regarding these techniques is reviewed and the personal experiences of the senior author with these techniques are also reported.

Comparison of 3D Printing Rapid Prototyping Technology with Traditional Radiographs in Evaluating Acetabular Defects in Revision Hip Arthroplasty: A Prospective and Consecutive Study

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.

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.

Custom-made 3D-printed cup-cage implants for complex acetabular revisions: evaluation of pre-planned versus achieved positioning and 1-year migration data in 10 patients

Background and purpose - The use of custom-made 3D-printed titanium implants for the reconstruction of large acetabular defects has been successively introduced in the last decade. In an observational cohort study we evaluated the agreement between preoperatively planned and actually achieved cup-cage position as well as 1-year follow-up migration of the cup-cage component.Patients and methods - 10 patients with Paprosky III defects underwent revision surgery using a custom-made 3D-printed cup-cage. The position of the implant on postoperative CT scan was compared with the preoperative plan and the postoperative CT scan was compared with the 1-year follow-up CT scan.Results - There was a median deviation in postoperative position versus planned in inclination of 3.6° (IQR 1.0-5.4), in anteversion of -2.8° (IQR -7.5 to 1.2), and in rotation of -1.2° (IQR -3.3 to 0.0). The median deviation in position of the center of rotation (COR) was -0.5 mm (IQR 2.9 to 0.7) in the anteroposterior (AP) plane, -0.6 mm (IQR -1.8 to -0.1) in the mediolateral (ML) plane, and 1.1 mm (IQR -1.6 to 2.8) in the superoinferior (SI) plane. The migration between postoperative and 1-year follow-up caused a mean change in inclination of 0.04° (IQR -0.06 to 0.09), in anteversion of -0.13° (IQR -0.23 to -0.06), and in rotation of 0.05° (IQR -0.46 to 1.4). The migration of COR was -0.08 mm (IQR -0.18 to -0.04) in the AP plane, 0.14 mm (IQR -0.08 to 0.22) in the ML plane, and 0.06 mm (IQR -0.02 to 0.35) in the SI plane. There was no re-revision.Interpretation - The early results show good agreement between planned and achieved cup-cage position and small measured migration values of the cup-cage component at the 1-year follow-up.

Do custom 3D-printed revision acetabular implants provide enough value to justify the additional costs? The health-economic comparison of a new porous 3D-printed hip implant for revision arthroplasty of Paprosky type 3B acetabular defects and its closest alternative

PURPOSE

Total hip arthroplasty (THA) is a common operation for patients suffering from hip arthrosis. It has been proven effective in improving quality of life while being cost-effective. Meanwhile, the number of revision hip arthroplasty is growing and those may require bone reconstruction and are potential indications for 3D custom implants. In these specific indications, medical 3D-printing has grown over the years and the use of 3D-printed implants has become more frequent. To date, the cost-effectiveness of 3D-printed implants for acetabular revision THA has not been evaluated. Therefore we performed a health economic analysis to: (1) analyse the cost-effectiveness of the aMace implant compared to its closest alternative on the market, (2) have a better insight into Belgian costs of revision hip arthroplasties and (3) estimate the budget impact in Belgium.

HYPOTHESIS

3D-printed acetabular implants provide good value-for-health in Paprosky type 3B defects in a Belgian setting.

MATERIAL AND METHODS

Custom Three-flanged Acetabular Components (CTAC) were compared to a 3D-printed implant (aMace) by means of a Markov model with four states (successful, re-revision, resection and dead). The cycle length was set at 6 months with a 10-year time horizon. Data was obtained through systematic literature search and provided by a large social security agency. The analysis was performed from a societal perspective. All amounts are displayed in 2019 euros. Discount rates were applied for future cost (3%) and QALY (1.5%) estimates.

RESULTS

Revision hip arthroplasty has an average societal cost of €9950 without implant. Based on the outcomes of our model, aMace provides an excellent value for money compared to CTAC. The Incremental Cost-Effectiveness Ratio (ICER) was negative for all age groups. The base case of a 65 year old person, showed a QALY gain of 0.05 with a cost reduction of €1265 compared to CTAC. The advantage of using aMace was found to be greater if a patient is younger. The re-revision rates of both CTAC and aMace and the utility of successful revision have the highest impact on costs and effects. A Monte Carlo simulation showed aMace to be a cost-effective strategy in 90% of simulations for younger patients and in 88% of simulations for patients above 85 years old. In Belgium it would imply a cost reduction of €20500 on an annual basis.

CONCLUSIONS

Based on the findings of this model, the new 3D-printed aMace implant has the potential to bring an excellent value for money when used in revision arthroplasty of Paprosky type 3B acetabular defects. For all patients, aMace resulted in a dominant, cost-saving strategy in Belgium compared to CTAC.

LEVEL OF EVIDENCE

III, comparative medico economical diagnostic tool.

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.

Bone impaction grafting with trabecular metal augments in large defects in young patients: unravelling a new perspective in surgical technique

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.

Two stage cementation and screw augmentation of large acetabular defects in low demand patients: Early results and surgical technique

INTRODUCTION

The reconstruction of large acetabular defects in revision hip arthroplasty represents a challenge to the surgeon and increases the complexity of the case. There are different options to overcome the problem of acetabular deficiency. In the elderly low demand patients, the main objective of revision surgery is to provide pain relief, allow immediate full weight bearing, and an early return to function.

METHODS

This article presents our experience in acetabular revision surgery using a novel technique of two stage cementation and screw augmentation in low demand patients. We report on the surgical technique and present the early results in 10 patients.

RESULTS

There were 6 females and 4 males with average age of 83.8 years. Patients were followed up for an average of 18.1 months. All patients were pain free and full weight bearing at the time of the final follow up with radiographs showing maintenance of implant position. None of the patients underwent revision surgery and there were no radiographic signs of failure detected in the early follow-up period.

CONCLUSION

This is a suitable technique in the management of large acetabular defects in revision hip arthroplasty, especially in the low demand patient population. It is a simple cost-effective technique that reduces the complexity of the acetabular revision, operative time, and morbidity associated with prolonged complex revision surgery.

Good implant survival after acetabular revision with extensive impaction bone grafting and uncemented components

Aims

This single-centre observational study aimed to describe the results of extensive bone impaction grafting of the whole acetabular cavity in combination with an uncemented component in acetabular revisions performed in a standardized manner since 1993.

Methods

Between 1993 and 2013, 370 patients with a median age of 72 years (interquartile range (IQR) 63 to 79 years) underwent acetabular revision surgery. Of these, 229 were more than ten years following surgery and 137 were more than 15 years. All revisions were performed with extensive use of morcellized allograft firmly impacted into the entire acetabular cavity, followed by insertion of an uncemented component with supplementary screw fixation. All types of reoperation were captured using review of radiographs and medical charts, combined with data from the local surgical register and the Swedish Hip Arthroplasty Register.

Results

Among patients with possible follow-up of ten and 15 years, 152 and 72 patients remained alive without revision of the acetabular component. The number of deaths was 61 and 50, respectively. Of those who died, six patients in each group had a reoperation performed before death. The number of patients with a reoperation was 22 for those with ten-year follow-up and 21 for those with 15 years of follow-up. The Kaplan-Meier implant survival rate for aseptic loosening among all 370 patients in the cohort was 96.3% (95% confidence interval (CI) 94.1 to 98.5) after ten years and 92.8% (95% CI 89.2 to 96.6) after 15 years.

Conclusion

Extensive bone impaction grafting combined with uncemented revision components appears to be a reliable method with favourable long-term survival. This technique offers the advantage of bone stock restoration and disputes the long-standing perception that uncemented components require > 50% of host bone contact for successful implant survival. Cite this article: Bone Joint J 2020;102-B(2):198–204.

Calcium Phosphate Bone Graft Substitutes with High Mechanical Load Capacity and High Degree of Interconnecting Porosity

Bone graft substitutes in orthopedic applications have to fulfill various demanding requirements. Most calcium phosphate (CaP) bone graft substitutes are highly porous to achieve bone regeneration, but typically lack mechanical stability. This study presents a novel approach, in which a scaffold structure with appropriate properties for bone regeneration emerges from the space between specifically shaped granules. The granule types were tetrapods (TEPO) and pyramids (PYRA), which were compared to porous CaP granules (CALC) and morselized bone chips (BC). Bulk materials of the granules were mechanically loaded with a peak pressure of 4 MP; i.e., comparable to the load occurring behind an acetabular cup. Mechanical loading reduced the volume of CALC and BC considerably (89% and 85%, respectively), indicating a collapse of the macroporous structure. Volumes of TEPO and PYRA remained almost constant (94% and 98%, respectively). After loading, the porosity was highest for BC (46%), lowest for CALC (25%) and comparable for TEPO and PYRA (37%). The pore spaces of TEPO and PYRA were highly interconnected in a way that a virtual object with a diameter of 150 µm could access 34% of the TEPO volume and 36% of the PYRA volume. This study shows that a bulk of dense CaP granules in form of tetrapods and pyramids can create a scaffold structure with load capacities suitable for the regeneration of an acetabular bone defect.

Reconstruction for pelvic discontinuity and massive acetabular defects

OBJECTIVE

The acetabular reconstruction with massive acetabular defects and pelvic discontinuity is a complex surgery with important difficulties for the orthopaedic surgeon. The objective of this study is to show the short and midterm results of the acetabular revision with the Cup-Cage construct in a consecutive serie of cases.

MATERIAL AND METHODS

Retrospectively we reviewed 22 consecutive patients with massive acetabular defects (8 Paprosky IIIa and 9 IIIB); 5 pelvic discontinuities; 2 pelvic fractures during the implantation of primary artroplasty, and one pelvic pseudoarthrosis. All were reoperated with a trabecular metal acetabular component and a Cup-Cage. We did clinical and radiological follow-up to detect machanical failures and loosening of the implant.

RESULTS

With a middle follow-up of 45.06 months (12-73 months) we did not see any radiographic failure of the implant (component migration, osteolysis neither rupture of the implant or screws). The complications (13,63%) included one recurrent luxation, one infection and one recurrent subluxation. The Merle d'Aubigné-Postel score improved from 6.91 to 14.36 and the punctuation in the range of motion from 2.91 to 4.36 on average of the values preoperatively and postoperatively respectively and improvement in Harris Hip Score 30 (16-55) to 72 (40-90) in the latest follow up.

CONCLUSION

The acetabular reconstruction with the Cup-Cage system is a valid alternative for the reconstruction of massive acetabular defects (Paprosky type IIIA and IIIB) and pelvic discontinuities offering good results at short and midterm follow-up.

Acetabular "up-and-in" defect treated with in-situ femoral head autograft technique during total hip arthroplasty

A 56-year-old male laborer with severe superior and medial acetabular protusio was treated with a cementless left total hip arthroplasty (THA) using an inexpensive technique that preserved the incarcerated femoral head in situ. The head was never dislocated, so the ligamentum was not disrupted. Wires stabilized the femoral head while reaming to prevent it from spinning, and multiple screws united the cup, autograft, and pelvis. At 2-year follow-up, the patient has pain-free hip function, radiographic union, and no component loosening or graft resorption.

Post-operative hip centre restoration and migration after impaction bone grafting in revision and complex primary hip arthroplasty

INTRODUCTION/OBJECTIVES

Although impaction grafting proved efficacy in the reconstruction of acetabular defects in primary and revision hip arthroplasty, its role in large segmental defects is still debatable. Our objective is to determine hip centre restoration and last follow-up migration after acetabular reconstruction with impaction grafting in different types of acetabular defects.

METHODS

This is a single-centre retrospective radiographic study of (107) total hip arthroplasty (42 primary and 65 revision) in (104) patients using impaction grafting. The available radiographs were examined for normal, preoperative, immediate postoperative, and last follow-up vertical (Y) and horizontal (X) hip centre. Maximum acetabular defect distance (MADD), presence, and size of the mesh were recorded.

RESULTS

In type I and II AAOS defects, the post-operative hip centre was not significantly different from the normal hip centre on the contralateral healthy side. In type III defects, there was a significant variation between the normal hip centre and the post-operative hip centre (P value 0.034 and 0.001 for Y and X, respectively). At 44-month follow-up of 36 hips, 31 (86%) hips migrated. The mean migration ± SD was 5.72 ± 3.7, 2, 4.15 ± 1.2, and 11.26 ± 3.9 mm for types I, II, and III, respectively (P value 0.211). Hips with MADD > 15 mm, especially with large mesh sizes migrate significantly more (P value = 0.042, 0.037, and 0.039, respectively).

CONCLUSION

Hip centre restoration was better, and migration was less for type I and II AAOS rather than for type III. Other options for reconstruction should be considered.

[Allogeneic bone transplantation in hip revision surgery : Indications and potential for reconstruction]

The increasing number of people having joint replacements will lead to increasing numbers of revision operations. The transplantation of allogeneic bones might reconstruct bone defects and improve long-term anchorage of the implant. A sufficient primary stability of the implanted construct is necessary to achieve osseous incorporation as well as tight contact between the implanted allogeneic and host bones. Transplantation of bone can contribute to downgrading acetabular defects and so avoid bigger reinforcement implants. An improvement of bone stock due to reconstruction of femoral bony defects might also reduce the size of the stem necessary since the indication might be limited in case of extensive bone defects. According to good longterm results of modular revision stems the Impaction-Bone-Grafting has not yet generally been established.

Lateral rim mesh in primary total hip arthroplasty

Aims

The aim of this study was to analyze the effect of a lateral rim mesh on the survival of primary total hip arthroplasty (THA) in young patients, aged 50 years or younger.

Patients and Methods

We compared a study group of 235 patients (257 hips) who received a primary THA with the use of impaction bone grafting (IBG) with an additional lateral rim mesh with a group of 306 patients (343 hips) who received IBG in the absence of a lateral rim mesh during the same period from 1988 to 2015. In the mesh group, there were 74 male and 183 female patients, with a mean age of 35 years (13 to 50). In the no-mesh group, there were 173 male and 170 female patients, with a mean age of 38 years (12.6 to 50). Cox regression analyses were performed to study the effect of a lateral rim mesh on acetabular component survival. Kaplan–Meier analyses with 95% confidence intervals (CIs) were performed to estimate the survival of the acetabular implant.

Results

The hazard ratio for the use of lateral rim mesh, adjusted for potential confounders, for acetabular revision for any reason was 0.50 (95% CI 0.13 to 1.93; p = 0.31) and for acetabular revision for aseptic loosening was 0.29 (95% CI 0.020 to 4.04; p = 0.35). The Kaplan–Meier analysis showed a ten-year survival for aseptic loosening of the acetabular of 98% (95% CI 95 to 100, n = 65 at risk) in the mesh group and 94% (89 to 98, n = 76 at risk) in the no-mesh group. The 15-year survival for aseptic acetabular loosening was 90% (81 to 100, n = 35 at risk) in the mesh group and 85% (77 to 94, n = 45 at risk) in the no-mesh group (p = 0.23).

Conclusion

This study shows that the use of a lateral rim mesh in primary THA in young patients is not associated with a higher risk of revision of the acetabular component. Therefore, we consider a lateral rim mesh combined with IBG to be effective in reconstructing segmental acetabular defects in primary THA.

Locally administered bisphosphonate in hip stem revisions using the bone impaction grafting technique: a randomised, placebo-controlled study with DXA and five-year RSA follow-up

BACKGROUND:

Bisphosphonates have previously been shown to increase the density of impacted graft bone. In the present study we hypothesise that bisphosphonates also reduce early stem subsidence. We examined the effect of locally applied bisphosphonate to allografts on prosthetic micromotion and bone density in femoral stem revision with impaction grafting.

METHODS:

37 patients were randomised to either clodronate or saline as local adjunct to the morsellised allograft bone. 24 patients were finally analysed per protocol and evaluated by dual-energy x-ray absorptiometry (DXA) during the first year and with radiostereometric analysis (RSA) for 5 years.

RESULTS:

There were no significant differences neither in bone density, nor in migratory behaviour between the groups. The femoral stems had subsided 3.6 mm in both groups (p = 0.99) at 5 years and there was no difference as measured over time with mixed models analysis. The clinical outcome was good in both groups.

CONCLUSION:

Clodronate as a local addendum to allograft bone in hip revision did not increase bone density or reduce micromotion of the implant.

Long-term results of acetabular reconstruction using irradiated allograft bone

AIMS

The management of acetabular defects at the time of revision hip arthroplasty surgery is a challenge. This study presents the results of a long-term follow-up study of the use of irradiated allograft bone in acetabular reconstruction.

PATIENTS AND METHODS

Between 1990 and 2000, 123 hips in 110 patients underwent acetabular reconstruction for aseptic loosening, using impaction bone grafting with frozen, irradiated, and morsellized femoral heads and a cemented acetabular component. A total of 55 men and 55 women with a mean age of 64.3 years (26 to 97) at the time of revision surgery are included in this study.

RESULTS

At a mean follow-up of 16.9 years, there had been 23 revisions (18.7%), including ten for infection, eight for aseptic loosening, and three for dislocation. Of the 66 surviving hips (58 patients) that could be reassessed, 50 hips (42 patients; 75.6%) were still functioning satisfactorily. Union of the graft had occurred in all hips with a surviving implant. Survival analysis for all indications was 80.6% at 15 years (55 patients at risk, 95% confidence interval (CI) 71.1 to 87.2) and 73.7% at 20 years (eight patients at risk, 95% CI 61.6 to 82.5).

CONCLUSION

Acetabular reconstruction using frozen, irradiated, and morsellized allograft bone and a cemented acetabular component is an effective method of treatment. It gives satisfactory long-term results and is comparable to other types of reconstruction. Cite this article: Bone Joint J 2018;100-B:1449-54.

Clinical and radiological outcomes of acetabular revision with the Delta Revision TT cup

INTRODUCTION:

This study evaluates mid-term results of acetabular revision using a hemispherical acetabular cup in Trabecular Titanium with a cage construct.

METHODS:

We reviewed 36 acetabular revisions performed with the Delta Revision TT cup in 34 patients (mean age = 75, range: 45-92 years). Acetabular defect types (Paprosky classification) included (1) 2B ( n = 5), (2) 2C ( n = 7), (3) 3A ( n = 15), and (4) 3B ( n = 9). Morcellised bone allografts were used in 24 cases, and synthetic bone used in 11. Outcomes were evaluated using the Harris Hip Score (HHS), and the Verbal Rating Scale (VRS) for pain measurement. X-ray visualisation of cup position was used to discern signs of mobilisation and bone graft incorporation. Survivorship at post-revision follow-up (mean = 39.8; range 12-91.5 months) was calculated.

RESULTS:

HHS increased from 40.5 to 87 ( p < 0.01). 68% of cases were pain free; by comparison, 32% had an average VRS score of 1.9 (range 1-3). The average cup inclination angle was 40.8° (30-52°) postoperatively, compared with 41.2° (30-52°) at follow-up; there were no signs of loosening or mobilisation. Centre of rotation was fully restored in 21 (58.3%) hips. According to Gie classification; bone graft incorporation grades were (1) 3 ( n = 21), (2) 2 ( n = 12) and (3) 1 ( n = 2). The survival rate was 100% for aseptic loosening and 91.7% for any cause of revision.

CONCLUSIONS:

The Delta Revision TT cup promises good clinical and radiographic results at short- to mid-term follow-up, with high rates of survival rate and bone integration.

The use of an Ossis custom 3D-printed tri-flanged acetabular implant for major bone loss: minimum 2-year follow-up

INTRODUCTION

Custom 3D-printed acetabular implants are a new technology used in hip surgery with ever-increasing frequency. They offer patient-specific implants to optimise filling of bone defects and implant-bone contact, without the need for excessive bone resection.

METHODS

This is a retrospective cohort study of 46 consecutive patients who underwent an Ossis unilateral custom 3D-printed acetabular implant. Clinical (Oxford Hip Score OHS-60), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS) and radiological (restoration of biomechanical hip centre, osteointegration, wear, heterotrophic ossification) results were assessed.

RESULTS

Patient mean age was 68 years and follow-up was 38 months (minimum 24 months). 10 patients were excluded from the outcome analysis; 2 patients died, 1 required revision for deep infection and 7 were lost to follow-up. Of the 36 patients included, 21 had severe osteolysis. 7 were revised for infection, 3 for tumoural defects, 3 for metallosis, 1 for dysplasia and 1 for trauma (Paprosky 2a [n=6], 2b [n=2], 2c [n=5], 3a [n=6], 3b [n=11], pelvic dissociation [n=6]). OHS significantly improved postoperatively (16-8-48.4 p=0.027). Postoperative functional scores were good (WOMAC 98; HHS 79). The biomechanical hip centre was restored in all patients. 1 patient had early implant migration with subsequent stabilisation. 2 patients had radiographs concerning for failure of osteointegration. 1 patient had recurrent dislocations.

CONCLUSIONS

The mid-term results of the Ossis custom 3D-printed tri-flanged acetabular implant for the management of severe acetabular defects are encouraging. The improvement in functional scores and radiographic outcomes are comparable to similar designs. In addition, no cases have required revision for aseptic loosening.

Revision Total Hip Arthroplasty for Paprosky Type III Acetabular Defect With Structural Allograft and Tantalum Trabecular Metal Acetabular Cup

There are several surgical options for addressing Paprosky type III acetabular defects during revision total hip arthroplasty. In physiologically young and active patients, using structural bone graft to restore bone defects and provide adequate initial support for the revision acetabular component is one such option. This study reports the mid-term results of using a structural allograft accompanied by a trabecular metal-coated hemispherical cup for Paprosky type III defects. A retrospective analysis was performed of the data collected for 20 consecutive hips in 20 patients (mean age, 56.2 years; range, 43-68 years) with minimum 3-year follow-up (mean, 5.4 years; range, 3.3-10.3 years) who had a structural allograft accompanied by a trabecular metal-coated hemispherical cup for Paprosky type III defects. Only 1 hip had cup migration, which was less than 3 mm in vertical and less than 5° in inclination and recognized as loosening without symptoms. All grafts showed good incorporation with trabecular bridging over the graft and host bone. The mean modified Harris hip score showed significant improvement, from 29.7 (range, 11-52) preoperatively to 84.1 (range, 77-91) at the latest follow-up (P<.05). The use of a structural allograft combined with a tantalum trabecular metal acetabular cup in acetabular revision for Paprosky type III defects had a satisfactory mid-term clinical result. This is a viable option for patients with large acetabular shelf defects. [Orthopedics. 2018; 41(6):e861-e867.].

Results of trabecular metal augments in Paprosky IIIA and IIIB defects

Aims

The advent of trabecular metal (TM) augments has revolutionized the management of severe bone defects during acetabular reconstruction. The purpose of this study was to evaluate patients undergoing revision total hip arthroplasty (THA) with the use of TM augments for reconstruction of Paprosky IIIA and IIIB defects.

Patients and Methods

A retrospective study was conducted at four centres between August 2008 and January 2015. Patients treated with TM augments and TM shell for a Paprosky grade IIIA or IIIB defect, in the absence of pelvic discontinuity, and who underwent revision hip arthroplasty with the use of TM augments were included in the study. A total of 41 patients with minimum follow-up of two years were included and evaluated using intention-to-treat analysis.

Results

There were 36 (87.8%) patients with a Paprosky IIIA defect and five (12.2%) patients with a Paprosky IIIB defect. The mean age was 56.7 years (28 to 94). There were 21 (51.2%) women and 20 (48.8%) men. The mean follow-up was 39.4 months (12 to 96). One (2%) patient died after eight years. No failures were noted in the series. The mean survivorship was 100% at the time of latest follow-up.

Conclusion

The results of this multicentre study showed encouraging short- and mid-term results for the use of TM augments in the management of Paprosky grade IIIA and IIIB defects. Cite this article: Bone Joint J 2018;100-B:903–8.

A 2- to 16-Year Clinical Follow-Up of Revision Total Hip Arthroplasty Using a New Acetabular Implant Combined With Impacted Bone Allografts and a Cemented Cup

BACKGROUND

Treatment of acetabular bone loss with impaction bone grafting (IBG) at revision total hip arthroplasty is highly dependent on mechanical stability and graft compression for clinical success. Here, we describe a new technique to further compress and stabilize the acetabular graft bed with a thin, perforated titanium shell.

METHODS

We retrospectively analyzed 170 cases of acetabular revision arthroplasty 7 years (standard deviation 2.8) after IBG combined with a graft-compressing titanium shell implant. The patients were reviewed by clinical score and radiography. Three patients were lost to follow-up. The medical journals of the 33 deceased cases were reviewed for any reoperation. Of the 170 cases, 74 had a cavitary acetabular bone defect, 93 had combined segmental and cavitary bone defects, and 3 had a pelvic dissociation. Bone graft incorporation was assessed and correction of the hip center of rotation was calculated.

RESULTS

Five cases (3%) were reoperated for mechanical loosening. One more was assessed as loose but asymptomatic and was not planned for revision. There were 3 reoperations for recurrent dislocation, 2 for deep infection and 1 for technical error. Reoperation for any reason, as the end point of survivorship, showed a survival rate of 92% after 10 years. Hip score according to Merle, d'Aubigne, and Postel increased from 10.8 (preoperatively) to 16.4 at follow-up. The clinical and radiological results were excellent.

CONCLUSION

IBG combined with the compressing shell results in excellent results for this challenging condition.

Acetabular Revision Using Trabecular Metal Augments for Paprosky Type 3 Defects

BACKGROUND

Trabecular Metal (TM) augments are one option when reconstructing bone loss during acetabular side revision surgery.

METHODS

We studied 38 consecutive patients with Paprosky type 3 defects that were revised using a TM shell and one or more augments over a 6-year period. There were 29 Paprosky type 3A defects and 9 Paprosky type 3B defects. The mean age of the patients at the time of surgery was 68.2 years (range 48-84). The mean length of follow-up was 36 months (range 18-74).

RESULTS

The mean preoperative short form 12 health survey improved from 27.7 before operation to 30.1 at the time of final follow-up (P = .001). The mean Western Ontario and McMaster Universities Osteoarthritis Index score improved from 53 preoperatively to a mean of 78.8 at final follow-up (P < .0001). There was evidence of radiographic loosening in 7 of the cup-augment constructs. One patient developed a deep infection requiring re-revision. Two patients required revision for aseptic loosening.

CONCLUSION

The use of TM in complex acetabular reconstruction is associated with good outcome in the short to medium term.

Determination of structural femoral head allograft viability and integrity with a novel diagnostic tool: SPECT/CT. A preliminary study

OBJECTIVE

To evaluate the viability and integrity of fresh frozen bulk femoral head allografts obtained from the institutional bone bank that were used to reconstruct severe acetabular defects and to validate the SPECT/CT method which gives both anatomical and functional data for this purpose.

METHODS

We retrospectively reviewed 9 patients (6 female, 3 male; mean age 63.6 years). Preoperative and postoperative leg lengths, existence of the Trendelenburg sign, range of motion of the hip, visual analogue score (VAS), Harris Hip Score (HHS) and any complication were assesed at each follow-up. Radiographically, position of the cup, signs of loosening or migration, and union of the graft were all determined. At the latest follow-up, patients were evaluated with hybrid SPECT/CT.

RESULTS

The average duration of follow-up was 38.1 months (24-50 months). The overall mean HHS and VAS scores were significantly improved (p<0.05). When hybrid SPECT/CT results were evaluated, the vascular phase of scintigraphy showed hyperaemia of the graft and the bone phase of scintigraphy showed normal or increased radiotracer uptake in the graft site in 7 patients. SPECT/CT images were used to determine the exact localisation of osteoblastic activity. 1 patient with minor resorption of the graft without clinical symptoms revealed mild osteoblastic activity. The patient who had no activity in the graft site was rerevised because of infection.

CONCLUSIONS

Institutional bank allografts are still excellent options for treating large acetabular defects in revision total hip arthroplasty where trabecular metals are not available or in common use. The Hybrid SPECT/CT method is a reliable, noninvasive method for evaluating both the integrity and viability of a bulk graft in 3-D.

Revision Total Hip Arthroplasty Using the Kerboull Acetabular Reinforcement Device and Structural Allograft for Severe Defects of the Acetabulum

BACKGROUND

The purpose of this study is to review our experience with Kerboull reinforcement device combined with bulk allograft for management of severe acetabular defects.

METHODS

We investigated the results of revision total hip arthroplasty (THA) in 65 hips of 59 patients (10 male, 49 female) with Paprosky type 3A or 3B acetabular bone defects. Functional outcome was assessed using the Merle d'Aubigne hip score. Post-operative radiographs were examined for evidence of cup loosening. The mean age at revision THA was 59.1 years (23-85) and mean follow-up duration was 11.2 years (2-15).

RESULTS

The Merle d'Aubigne hip score improved from 10.6 points (5-15) before surgery to 17.1 points (15-18) (P < .05) at the time of last investigation. In this series, mean coverage of the bone graft was 83.0% (34.6-100) of the loading portion in the horizontal plane on radiography immediately after revision. However, consolidation of the bone graft was completed within 12 months for all cases. There were 4 radiological failures due to acetabular aseptic loosening at a mean of 10.8 years (8-13) after index surgery; all 4 cases demonstrated massive bone loss that no part of the rounded plate could be placed on the host bone. Kaplan-Meier analysis showed that the 15.2-year survival rate was 85.1% (95% confidence interval 71-99) with re-revision surgery for any reason as the end point.

CONCLUSION

Despite massive bone defects, we achieved favorable results for revision THA using bulk allograft and the Kerboull reinforcement device.

Revision Total Hip Arthroplasty Using a Cementless Cup Supporter and Iliac Autograft: A Minimum of 15-Year Follow-Up

BACKGROUND

Bone deficiency in revision total hip arthroplasty is a surgical challenge. The Murata-Chiba cup supporter (MC support ring) is an acetabular component supporter for a cementless porous-coated cup. The purpose of this study is to examine the clinical and radiographic outcomes of reconstruction of acetabular bone deficiency using iliac autografts supported by an MC support ring in a revision setting with minimum 15-year follow-up.

METHODS

Fifty-nine consecutive revision total hip arthroplasties (57 patients) using the MC support ring were followed for a minimum of 15 years. Nine hips had American Academy of Orthopaedic Surgeons type II deficiency and 24 had type III defects of the acetabulum. Clinical outcomes were evaluated using the Harris hip score. Radiographic evaluation included assessment for loosening and bone graft incorporation. Kaplan-Meier survival analysis was performed.

RESULTS

At a minimum 15-year follow-up (mean, 17.6 years), 32 patients (33 hips) were alive, 17 patients (18 hips) were deceased, and 8 patients (8 hips) were lost to follow-up. The mean Harris hip score improved from 44.3 to 77.2 at final follow-up. Four hips required reoperation due to deep infection (2 hips) and liner dissociation (2 hips), but no acetabular components were revised for aseptic loosening. Incorporation of the bone graft occurred in all cases. One unrevised patient had radiographic failure. Survivorship at 15 years with re-revision or radiographic failure as the end point was 90.6% (95% confidence interval, 83.0%-98.8%).

CONCLUSION

The reconstruction of acetabular bone deficiency using autografts supported by an MC support ring provided satisfactory clinical and radiological results at 17.6 years postoperatively.

[Biological downsizing : Acetabular defect reconstruction in revision total hip arthroplasty]

BACKGROUND

Periacetabular bony defects remain a great challenge in revision total hip arthroplasty. After assessment and classification of the defect and selection of a suitable implant the primary stable fixation and sufficient biological reconstitution of a sustainable bone stock are essential for long term success in acetabular revision surgery. Biological defect reconstruction aims for the down-sizing of periacetabular defects for later revision surgeries.

TECHNIQUE

In the field of biological augmentation several methods are currently available. Autologous transplants feature a profound osseointegrative capacity. However, limitations such as volume restrictions and secondary complications at the donor site have to be considered. Structural allografts show little weight bearing potential in the long term and high failure rates. In clinical practice, the usage of spongious chips implanted via impaction bone grafting technique in combination with antiprotrusio cages for the management of contained defects have shown promising long time results. Nevertheless, when dealing with craniolateral acetabular and dorsal column defects, the additional implantation of macroporous metal implants or augments should be considered since biological augmentation has shown little clinical success in these particular cases.

PROSPECT

This article provides an overview of the current clinically available biological augmentation methods of peri-acetabular defects. Due to the limitations of autologous and allogeneic bone transplants in terms of size and availability, the emerging field of innovative implantable tissue engineering constructs gains interest and will also be discussed in this article.

The cup-cage reconstruction for pelvic discontinuity has encouraging patient satisfaction and functional outcome at median 6-year follow-up

INTRODUCTION

The aim of this study was to review the clinical, radiological and patient-reported outcomes with the use of cup-cage construct for pelvic discontinuity at our institution.

METHODS

24 patients were identified at median 6-year (minimum 2 year, maximum 10 years) follow-up. 1 patient was converted to excision arthroplasty for infection. A further 3 patients required revision for instability but the cup-cage construct was not revised.

RESULTS

We noted encouraging pain relief (mean WOMAC pain 85.6) and good functional outcome (mean WOMAC function 78.2, mean UCLA 5, mean OHS 78.6). Patient satisfaction with regards pain relief, function and return to recreational activities were noted to be good.

CONCLUSIONS

The cup-cage construct is a viable method of dealing with complex pelvic discontinuity. However, the failure rate due to loosening (4 cases) in this and other reports does prompt the need for further refinement of the technique and technology in this very challenging group of patients, as well as continued evaluation at the mid- and long-term so as to confirm the ongoing success of this method of reconstruction.

Acetabular Defect Reconstruction with Trabecular Metal Augments: Study with Minimum One-year Follow-up

Purpose

High rates of mechanical failure have been reported in type III acetabular defects. Recently porous trabecular metal augments have been introduced with, excellent biomechanical characteristics and biocompatibility, allowing early stability and greater bone ingrowth. The aim of the study was to assess the short term clinical and radiological outcome of the trabecular metal augments.

Materials and Methods

We performed, 22 revision total hip arthroplasties (THA) and 6 primary THA (total 28) using trabecular metal augments to reconstruct acetabular defect between 2011 to 2015. Among 28 patients, 18 were males, 10 females. Mean age of patients was 61.21 years. Paprosky classification for acetabular bone defects was used. Eighteen cases were classified as grade 3 A and 10 cases as grade 3B. Hip center was calculated in each case preoperatively and compared postoperatively to check whether it has been brought down. Clinical outcome assessed using Harris hip score (HHS) and radiological outcomes as osteolysis in acetabular zones and osseointegration, according to Moore's criteria.

Results

HHS improved from 58.00 to 86.20. Centre of rotation of hip joint corrected from 38.90 mm preoperatively to 23.85 mm postoperatively above the interteardrop line. Among 28 patients, 18 patients had three or more signs of osseointegration (Moore's criteria), during final follow up and 10 had one/two signs. No radiolucency, osteolysis, or loosening found during follow up radiographic examination.

Conclusion

Our study showed that trabecular metal augments were highly satisfactory in short term. However, long term study is required for better evaluation.

Acetabular revision in total hip arthroplasty with tantalum augmentation and lyophilized bovine xenograft

Objective

To evaluate a mixed technique of acetabular reconstruction, which uses trabecular metal in the form of tantalum augments associated with lyophilized bovine xenograft.

Methods

Fifteen patients were evaluated prospectively, who underwent acetabular reconstruction with impacted lyophilized bovine xenograft associated with the use of tantalum augments. The main outcome was the failure of the tantalum–bone interface.

Results

The population had a mean age of 58.33 years ± 14.27; the majority was female, 80%. Of the total subjects, 66.7% were operated for failure in primary arthroplasty. The mean follow-up time was 45.2 months ± 11.39. The failure rate of the method in the period and population studied was 6.7%.

Conclusion

An extremely high index (93.3%) of success was observed in an average time of 45.2 months of follow-up. Data were comparable to current literature, demonstrating that the technique employed and proposed is adequate for hip reconstruction in young patients.

The Influence of Liquids on the Mechanical Properties of Allografts in Bone Impaction Grafting

Allografts are used to compensate for bone defects resulting from revision surgery, tumor surgery, and reconstructive bone surgery. Although it is well known that the reduction of fat content of allografts increases mechanical properties, the content of liquids with a known grain size distribution has not been assessed so far. The aim of the study was to compare the mechanical properties of dried allografts (DA) with allografts mixed with a saline solution (ASS) and with allografts mixed with blood (AB) having a similar grain size distribution. Fresh-frozen morselized bone chips were cleaned chemically, sieved, and reassembled in specific portions with a known grain size distribution. A uniaxial compression was used to assess the yield limit, initial density, density at yield limit, and flowability of the three groups before and after compaction with a fall hammer apparatus. No statistically significant difference could be found for the yield limit between DA and ASS (p = 0.339) and between ASS and AB (p = 0.554). DA showed a statistically significant higher yield limit than AB (p = 0.022). Excluding the effect of the grain size distribution on the mechanical properties, it was shown that allografts have a lower yield limit when lipids are present. The liquid content of allografts seems to play an inferior role as no statistically significant difference could be found between DA and ASS. It is suggested, in accordance with other studies, to chemically clean allografts before implantation to reduce the contamination risk and the fat content.

Promising early results for trabecular metal acetabular components used at revision total hip arthroplasty

Aims

The aim of this study was to compare the incidence of aseptic loosening after the use of a cemented acetabular component and a Trabecular Metal (TM) acetabular component (Zimmer Inc., Warsaw, Indiana) at acetabular revision with bone impaction grafting.

Patients and Methods

A total of 42 patients were included in the study. Patients were randomised to receive an all- polyethylene cemented acetabular component (n = 19) or a TM component (n = 23). Radiostereometric analysis and conventional radiographic examinations were performed regularly up to two years post-operatively or until further revision.

Results

The proximal migration was significantly higher in the cemented group. At two years, the median proximal migration was 1.45 mm and 0.25 mm in the cemented and TM groups, respectively (p = 0.02). One cemented component was revised due to dislocation. There were no revisions in the TM group.

Conclusion

Lower proximal migration in the TM group suggests that this design might be associated with a lower risk of aseptic loosening in the long term compared with an all polyethylene cemented component. Longer follow-up is required to confirm the clinical advantages of using this component at acetabular revision. Cite this article: Bone Joint J 2017;99-B:880–6.

Minimum Five-Year Outcomes with Porous Tantalum Acetabular Cup and Augment Construct in Complex Revision Total Hip Arthroplasty

BACKGROUND

The use of a trabecular metal revision shell with metal augmentation to fill segmental or irregular defects during complex revision hip arthroplasty has been shown to provide good short-term results in prior published series. Longer-term results of the several cup-augment constructs used clinically are not known. The objective of this study was to report, with minimum 5-year radiographic and clinical follow-up, the outcome of these various constructs in revision total hip arthroplasty.

METHODS

Eighty-four patients (85 hips) underwent revision total hip arthroplasty with use of porous tantalum augments between 2000 and 2007 at a single institution and were retrospectively reviewed. Fifty-seven of the patients (58 hips) had clinical and radiographic follow-up at a minimum of 5 years. At the time of revision, the majority of the hips had acetabular defects classified as Paprosky Type 3A (28 of 58, 48%) or Type 3B (22 of 58, 38%). Eleven (19%) of the hips also had preoperative pelvic discontinuity. All hips were assessed clinically at a minimum of 5 years with use of the Mayo hip score. Postoperative radiographs were reviewed for implant stability, the presence and location of radiolucent lines and healing of the discontinuity if present.

RESULTS

In 2 (3%) of the 58 hips, the constructs failed because of aseptic loosening of the acetabular component and re-revision was indicated. Six (10%) of the 58 hips demonstrated a radiolucent line between the trabecular metal shell and bone in DeLee and Charnley zone 3. In 1 hip that underwent re-revision and in 5 of the 6 hips with a zone-3 radiolucency, a pelvic discontinuity was present at the time of the index revision. The mean preoperative Mayo hip score was 35.7, which improved to 61.9 at 3 months and was 61.7 at the minimum 5-year follow-up.

CONCLUSIONS

With failure defined as aseptic loosening requiring repeat revision surgery, this cohort demonstrated 97% survivorship and maintained satisfactory hip function at the minimum 5 years after the index revision surgery. Six of the 11 hips with preoperative pelvic discontinuity either failed or developed a radiolucency in zone 3 and are considered at risk for future revision. Pelvic discontinuity should prompt consideration of the addition of adjunctive fixation or the use of alternative techniques.

LEVEL OF EVIDENCE

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

High proximal migration in cemented acetabular revisions operated with bone impaction grafting; 47 revision cups followed with RSA for 17 years

BACKGROUND

Bone impaction grafting is a biologically and mechanically appealing option in acetabular revision surgery, allowing restitution of the bone stock and restoration of the biomechanics. We analysed differences in proximal migration of the revision acetabular components when bone impaction grafting is used together with a cemented or an uncemented cup.

PATIENTS AND METHODS

43 patients (47 hips), revised due to acetabular loosening and judged to have less than 50% host bone-implant contact were included. The hips were randomised to either an uncemented (n = 20) or a cemented (n = 27) revision cup. Radiostereometry and radiography was performed postoperatively, at 3 and 6 months, 1, 2, 3, 5, 7, 10 and 13 and 17 years postoperatively. Clinical follow-up was performed at 1, 2 and 5 years postoperatively and thereafter at the same interval as in the radiographic follow-up.

RESULTS

There were no differences in the base line demographic data between the 2 groups. At the last follow-up (17 years) 14 hips (10 cemented, 4 uncemented) had been re-revised due to loosening. 3 additional cups (1 uncemented and 2 cemented) were radiographically loose. There was a higher early proximal migration in the cemented cups.

DISCUSSION

Cups operated on with cement showed a higher early migration measured with RSA and also a higher number of late revisions. The reason for this is not known, but factors such as inclusion of cases with severe bone defects, use of smaller bone chips and issues related to the impaction technique might have had various degrees of influence.

Bone grafts, bone graft extenders, substitutes and enhancers for acetabular reconstruction in revision total hip arthroplasty

Acetabular bone loss is a relevant concern for surgeons dealing with a failed total hip arthroplasty.

Since the femoral head is no longer available, allografts represent the first choice for most reconstructive solutions, either as a structural buttress or impacted bone chips.

Even though fresh-frozen bone is firmly recommended for structural grafts, freeze-dried and/or irradiated bone may be used alternatively for impaction grafting. Indeed, there are some papers on freeze-dried or irradiated bone impaction grafting, but their number is limited, as is the number of cases.

Xenografts do not represent a viable option based on the poor available evidence but bioactive bioceramics such as hydroxyapatite and biphasic calcium phosphates are suitable bone graft extenders or even substitutes for acetabular impaction grafting.

Bone-marrow-derived mesenchymal stem cells and demineralised bone matrix seem to act as reliable bone graft enhancers, i.e. adjuvant therapies able to improve the biological performance of standard bone grafts or substitutes. Among these therapies, platelet-rich plasma and bone morphogenetic proteins need to be investigated further before any recommendations can be made.

Cite this article: EFORT Open Rev 2016;1:431-439. DOI:10.1302/2058-5241.160025