The survival and fate of acetabular reconstruction with impaction grafting for large defects

Precision pore structure optimization of additive manufacturing porous tantalum scaffolds for bone regeneration: A proof-of-concept study

Currently, the treatment of bone defects in arthroplasty is a challenge in clinical practice. Nonetheless, commercially available orthopaedic scaffolds have shown limited therapeutic effects for large bone defects, especially for massiveand irregular defects. Additively manufactured porous tantalum, in particular, has emerged as a promising material for such scaffolds and is widely used in orthopaedics for its exceptional biocompatibility, osteoinduction, and mechanical properties. Porous tantalum has also exhibited unique advantages in personalised rapid manufacturing, which allows for the creation of customised scaffolds with complex geometric shapes for clinical applications at a low cost and high efficiency. However, studies on the effect of the pore structure of additively manufactured porous tantalum on bone regeneration have been rare. In this study, our group designed and fabricated a batch of precision porous tantalum scaffolds via laser powder bed fusion (LPBF) with pore sizes of 250 μm (Ta 250), 450 μm (Ta 450), 650 μm (Ta 650), and 850 μm (Ta 850). We then performed a series of in vitro experiments and observed that all four groups showed good biocompatibility. In particular, Ta 450 demonstrated the best osteogenic performance. Afterwards, our team used a rat bone defect model to determine the in vivo osteogenic effects. Based on micro-computed tomography and histology, we identified that Ta 450 exhibited the best bone ingrowth performance. Subsequently, sheep femur and hip defect models were used to further confirm the osteogenic effects of Ta 450 scaffolds. Finally, we verified the aforementioned in vitro and in vivo results via clinical application (seven patients waiting for revision total hip arthroplasty) of the Ta 450 scaffold. The clinical results confirmed that Ta 450 had satisfactory clinical outcomes up to the 12-month follow-up. In summary, our findings indicate that 450 μm is the suitable pore size for porous tantalum scaffolds. This study may provide a new therapeutic strategy for the treatment of massive, irreparable, and protracted bone defects in arthroplasty.

Use of morselized bone allograft in revision hip arthroplasty for massive acetabular defect: A systematic review and meta-analysis

Purpose

Many treatment options are available for the revision of large acetabular defects. Debate continues as to which technique is most effective. This meta-analysis aimed to determine the rates of failure of acetabular bone defects Paprosky type III or American Academy of Orthopaedic types III-IV treated with morselized allograft in association with cemented cup or cementless cup or reinforcement devices.

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 1 April 2024 utilizing keywords pertinent to total hip arthroplasty (THA), acetabular impaction bone grafting and revision THA. The main outcome measure was the 9-year implant failure rate.

Results

Thirty-nine articles were eligible for inclusion in the current study. We found 41 treatment approaches that we grouped into three different treatment options: 1 = morselized allograft and cemented cup (10 studies); 2 =morselized allograft and cementless cup (nine studies); 3 = morselized allograft and device (22 studies). The overall implant failure rate was 2.1% (95% confidence interval [CI], 1.6%-2.8%) at a mean of 9.2 years. There was no significant difference in failure rates between different treatment options (1.6% [95% CI, 0.9%-2.6%]) for morselized allograft and cemented cup; 2.1% (95% CI, 1.4%-3.2%) for morselized allograft and cementless cup; 2.5% (95% CI, 1.7%-3.7%) for morselized allograft and device) between the three different types of treatment (heterogeneity between groups p = 0.351).It was determined that the number one cause of failure was aseptic loosening (80.5%), followed by infection (13.1%) and dislocation (6.4%). THA with reinforcement devices has a higher incidence of infection (3.6 vs. 0.7%, p = 0.001) and dislocation (1.4 vs. 0.6%, p = 0.010) than THA with a cemented cup.

Conclusions

The use of morselized allograft in hip revision of large acetabular defects has low implant failure rates, independently of the associated type of implant. Reinforcement devices increase the risk of re-revision for infection and dislocation.

Level of Evidence

Level III.

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.

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.

Impaction Bone Grafting Combined with Titanium Mesh for Acetabular Bone Defects Reconstruction in Total Hip Arthroplasty Revision: A Retrospective and Mini-Review Study

Objective

To investigate the application of impaction bone grafting (IBG) combined with Ti‐alloy mesh for acetabular bone defect reconstruction in total hip arthroplasty (THA) revision and follow up the clinical outcomes and imaging findings.

Methods

The clinical and imaging data of patients who were admitted to our hospital from January 2000 to December 2020 and underwent acetabular bone defects reconstruction using IBG combined with titanium mesh were retrospectively analyzed. Preoperative and post‐revision Oxford and Harris scores, and post‐revision complications were evaluated. Radiographs were used to determine center of rotation (COR) of the hip joint, transparency line, bone graft fusion, and bone mineral density (BMD) around the hip joint.

Results

Significant improvement was observed in both Oxford and Harris scores (P < 0.05). The radiographs taken at the last follow‐up examination showed no significant differences in the acetabulum COR, offsets, inclination angle, mean ratio of vertical value, and BMD analysis between the post‐revision side and contralateral side (P > 0.05). The follow‐up data showed restoration of the mesh implant and graft bone fusion.

Conclusions

The application of IBG combined with titanium‐alloy mesh in revision THA patients with acetabular defects was found to provide satisfactory outcomes. However, large‐scale studies are still needed to further elucidate the long‐term outcomes.

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.

Impaction bone grafting in hip re-revision surgery

AIMS

Bone stock restoration of acetabular bone defects using impaction bone grafting (IBG) in total hip arthroplasty may facilitate future re-revision in the event of failure of the reconstruction. We hypothesized that the acetabular bone defect during re-revision surgery after IBG was smaller than during the previous revision surgery. The clinical and radiological results of re-revisions with repeated use of IBG were also analyzed.

METHODS

In a series of 382 acetabular revisions using IBG and a cemented component, 45 hips (45 patients) that had failed due to aseptic loosening were re-revised between 1992 and 2016. Acetabular bone defects graded according to Paprosky during the first and the re-revision surgery were compared. Clinical and radiological findings were analyzed over time. Survival analysis was performed using a competing risk analysis.

RESULTS

Intraoperative bone defect during the initial revision included 19 Paprosky type IIIA and 29 Paprosky type IIIB hips; at re-revision, seven hips were Paprosky type II, 27 type IIIA and 11 were type IIIB (p = 0.020). The mean preoperative Harris Hip Score was 45.4 (SD 6.4), becoming 80.7 (SD 12.7) at the final follow-up. In all, 12 hips showed radiological migration of the acetabular component, and three required further revision surgery. The nine-year cumulative failure incidence (nine patients at risk) of the acetabular component for further revision surgery was 9.6% (95% confidence interval (CI) 2.9 to 21.0) for any cause, and 7.5% (95% CI 1.9 to 18.5) for aseptic loosening. Hips with a greater hip height had a higher risk for radiological migration (odds ratio 1.09, 95% CI 1.02 to 1.17; p = 0.008).

CONCLUSION

Bone stock restoration can be obtained using IBG in revision hip surgery. This technique is also useful in re-revision surgery; however, a better surgical technique including a closer distance to hip rotation centre could decrease the risk of radiological migration of the acetabular component. A longer follow-up is required to assess potential fixation deterioration. Cite this article: Bone Joint J 2021;103-B(3):492-499.

Reconstruction of Acetabular Defects With Impaction Grafting in Primary Cemented Total Hip Arthroplasty Produces Favorable Results: Clinical and Radiographic Outcomes Over 6.4 Years on Average

BACKGROUND

Cemented primary total hip arthroplasty (THA) associated with acetabular reconstruction (AR) involving impacted bone grafting has been employed successfully in the revision of cavitary defects but the results are reportedly less predictable for segmental defects. The objective of the study is to evaluate the clinical and radiographic results of patients who had presented cavitary, segmental, and combined acetabular defects and received THA/AR involving impacted morselized cancellous bone autografts followed by rigorous postoperative management.

METHODS

Clinical outcomes were assessed retrospectively of 154 patients who had been submitted to 169 THA/AR procedures performed by a single surgeon over a 15-year period. The Harris Hip Score system was applied to 103 patients, and the degree of acetabular migration was determined from radiograph images of 91 AR procedures, of which 40 were segmental/combined and 51 were cavitary reconstructions.

RESULTS

The frequency of aseptic acetabular loosening was 3% while that of thromboembolic events was 4.1%. According to Harris Hip Score, 87.4% of outcomes were classified as excellent/good after an average follow-up period of 6.4 years irrespective of the type of acetabular defect. Horizontal and/or vertical acetabular migrations and changes in angular tilt were observed in all ARs, although the minor movements detected did not undermine the structural stability of the reconstructions or the functional capacity of patients.

CONCLUSION

The described THA/AR technique can be used effectively in the reconstruction of segmental/combined and cavitary acetabular defects. The success of the technique as applied to segmental/combined defects was attributed in part to the rigorous rehabilitation protocol with temporary postoperative weight-bearing restriction.

Clinical and radiological survivorship of the Thackray cross plate with rim reinforcement ring for cemented acetabular revision

INTRODUCTION

Acetabular component revision surgery can be a challenging task due to the encountered bone defects. Both cemented and uncemented techniques are described. We report on the survivorship of the Thackray cross plate with rim reinforcement ring for cemented acetabular revision.

PATIENTS AND METHODS

This is a retrospective case series of all patients treated with the implant with a minimum follow-up of 2 years. Acetabular defects were characterized according to the Paprosky classification. Data on potential risk factors for failure of the construct as well as the Oxford Hip Score (OHS) were collected. Kaplan-Meier survival analysis with radiographic aseptic loosening or revision for aseptic loosening as the end point was performed.

RESULTS

From 2000 to 2017, 35 revisions in 18 male and 17 female patients with an average age of 72 years were included. Bone allograft was used in 26 cases and additional implants (medial or supero-lateral mesh) in 13. Seven patients have deceased and the fate of all revisions is known. At an average clinical follow-up of 9.7 (2.6 to 19.6) years, there were no further re-revisions for construct failure. Five hips have demonstrated radiological evidence of aseptic loosening. Radiologically loose components were associated with more severe grades of acetabular bone defects (Paprosky Type 3) (60% vs 3%, p = 0.006). Kaplan-Meier survival analysis demonstrates 79.8% overall survivorship at 7 years. Survivorship for Type 2 defects was significantly higher compared to Type 3 (90% vs 0% at 7 years, Logrank test p = 0.002, Cox proportional hazards p = 0.03). The final median OHS was 38 (12-48) and was not affected by component loosening.

CONCLUSION

This is a cost-effective device that protects the underlying bone graft (81% complete remodeling) and prevents subsidence of the cemented cup (2 mm on average). It should be used with caution in high-grade defects and perhaps not advised.

Mid-term results of revision surgery using double-trabecular metal cups alone or combined with impaction bone grafting for complex acetabular defects

BACKGROUND

Revision surgery for complex acetabular defects is still technically challenging. In this study, we discussed and compared the clinical and radiological outcomes of revision surgery between two methods using double-trabecular metal (TM) cups alone or combined with impacting bone grafting (IBG).

METHODS

The records of 18 patients (18 hips) who underwent revision surgery using double-trabecular metal (double-TM) cups between 2008 and 2016 were retrospectively reviewed. All the patients were diagnosed with Paprosky III acetabular defects. The acetabular defects were reconstructed by double-TM cups alone or in combination with IBG. We used the modified Harris Hip Score (mHHS), University of California, Los Angeles (UCLA), and Short Form 36 (SF-36) to evaluate the clinical outcomes. Pelvis plain X-ray was used to assess hip center of rotation (COR), abduction angle and anteversion angle of acetabular cup, and incorporation of the bone graft to host bone.

RESULTS

The median follow-up time was 61.0 (IQR 56.0 to 65.8) months. No patients underwent re-revision for loosening or any other reasons. Complications included 3 patients (16.7%) with early dislocation and 3 patients (16.7%) with delayed wound healing. The average mHHS and UCLA preoperatively were 44.1 ± 4.0 (range 35 to 50) and 2.6 ± 0.7 (range 2 to 4), respectively and at the last follow-up were 73.7 ± 4.2 (range 68 to 85) and 7.3 ± 0.5 (range 7 to 8), respectively. The mean SF-36 scores at the last follow-up were improved significantly than preoperative scores, especially in bodily pain category (P < 0.05). The average limb-length discrepancy (LLD) decreased significantly from 24.2 ± 2.6 (range 20 to 32) mm preoperatively to 5.8 ± 1.8 (range 3 to 9) mm at the last follow-up, respectively. However, there was no significant difference between two methods at the last follow-up in terms of mHHS, UCLA, SF-36, LLD, and hip COR (P > 0.05). Radiographic evaluation demonstrated bone graft incorporation in all hips in the follow-up.

CONCLUSIONS

Defect reconstruction using double-TM cups alone or combined with IBG are practical and reliable treatment options for Paprosky III acetabular defects without pelvic discontinuity. Nevertheless, high postoperative complication rate, especially in terms of dislocation, remains a challenge.

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.

Fixation Stability of Uncemented Acetabular Cups With Respect to Different Bone Defect Sizes

BACKGROUND

In total hip arthroplasty, acetabular press-fit cups require a proper bone stock for sufficient primary implant fixation. The presence of acetabular bone defects compromises the primary fixation stability of acetabular press-fit cups. The aim of the present study is to determine the fixation stability of a cementless acetabular cup regarding standardized bone defects in an experimental setup.

METHODS

An acetabular defect model was developed and transferred to a biomechanical cup-block model. The lack of superior cup coverage was divided into 4 stages of superior rim loss (33%, 50%, 67%, and 83%) in the anterior-posterior direction and into 4 stages of mediolateral wall absence (11%, 22%, 33%, and 50%). This resulted in 11 different defect cavities, which were compared to the intact cavity in push-in and lever-out tests of one press-fit cup design (56 mm outer diameter). Thereby, push-in force, lever-out moment, lever-out angle, and interface stiffness were determined.

RESULTS

The determined lever-out moments range from 15.53 ± 1.38 Nm (intact cavity) to 1.37 ± 0.54 Nm (83%/50% defect). Smaller defects (33%/11%, 33%/22%, and 50%/11%) reduce the lever-out moments by an average of 33.9% ± 2.8%.

CONCLUSION

The lack of mediolateral acetabular coverage of 50% was assessed as critical for cementless cup fixation, whereby the contact zone between implant and bone in the defect is lost. A lack of 20% to 30% mediolateral coverage appears to be acceptable for press-fit cup fixation in the presence of primary stability. A defect of 50%/50% was identified as the threshold for using additional fixation methods.

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.

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.

ACETABULAR RECONSTRUCTION IN PAPROSKY TYPE III DEFECTS

Objectives

Severe pelvic deficiency presents a difficult problem in hip arthroplasty. Specifically, the goals are to restore the pelvic bone stock, place the acetabular component in the correct anatomical position, and optimize joint stability. Currently, many surgical techniques have been developed for prosthetic revision surgery for acetabular complex defects, but no consensus has been reached on the best treatment. The objective of this study was to review mid-term cases of severe bone defect (Paprosky type III) treated with a bone allograft and ring Bursch-Schneider anti-protrusion cage (BSAC).

Methods

A retrospective consecutive series review of the first 23 complex acetabular reconstructions performed between 2006 and 2011 was conducted. The series included the learning curve of the procedure and a minimum 5-year follow-up.

Conclusion

Our study confirmed the efficacy of using a frozen morselized allograft combined with a metal ring-type BSAC for acetabular reconstruction. The anatomical location of the center of rotation of the hip must be recovered for long-term success. In massive loosening cases, the anatomical center of rotation can only be restored by bone density reconstruction using a graft protected by a ring to improve the centering of the head. Level of Evidence IV, Case Series.

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.

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.

Revision total hip arthroplasty using the Kerboull acetabular reinforcement device for Paprosky type III defects involving the inferior margin of the acetabulum: a minimum five-year follow-up study

Aims

The purpose of this retrospective study was to evaluate the minimum five-year outcome of revision total hip arthroplasty (THA) using the Kerboull acetabular reinforcement device (KARD) in patients with Paprosky type III acetabular defects and destruction of the inferior margin of the acetabulum.

Patients and Methods

We identified 36 patients (37 hips) who underwent revision THA under these circumstances using the KARD, fresh frozen allograft femoral heads, and reconstruction of the inferior margin of the acetabulum. The Merle d'Aubigné system was used for clinical assessment. Serial anteroposterior pelvic radiographs were used to assess migration of the acetabular component.

Results

At a mean follow-up of 8.2 years (5 to 19.3), the mean Merle d'Aubigné score increased from 12.5 (5 to 18) preoperatively to 16.5 (10 to 18) (p < 0.0001). The survival rate at ten years was 95.3% (sd 4.5; 95% confidence interval (CI) 86.4 to 100) and 76.5% (sd 9.9, 95% CI 57.0 to 95.9) using aseptic loosening and radiological loosening as the endpoints, respectively.

Conclusion

These results show that the use of the KARD with reconstruction of the inferior margin of the acetabulum in revision THA is associated with acceptable clinical results and survival at mid-term follow-up with, however, a high rate of migration of the acetabular component of 21.6%. Cite this article: Bone Joint J 2018;100-B:725-32.

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.

Decreased migration with locally administered bisphosphonate in cemented cup revisions using impaction bone grafting technique

Background and purpose - Impaction bone grafting (IBG) in revision hip surgery is an established method in restoring bone stock deficiencies. We hypothesized that local treatment of the morsellized allograft with a bisphosphonate in cemented revision would, in addition to increased bone density, also reduce the early migration of the cup as measured by radiostereometry (RSA). Patients and methods - 20 patients with aseptic cup loosening underwent revision using the IBG technique. The patients were randomized to either clodronate (10 patients) or saline (10 patients, control group) as local adjunct to the morsellized bone. The outcome was evaluated by dual-energy X-ray absorptiometry (DXA) during the first year regarding periacetabular bone density and with radiostereometric analysis (RSA) for the first 2 years regarding cup migration. Results - 2 patients were lost to follow-up: 9 patients remained in the clodronate and 9 in the control group. Less proximal migration was found in the clodronate group compared with the controls, measured both over time (mixed-models analysis, p = 0.02) as well as at the specified time points up to 2 years (0.22 mm and 0.59 mm respectively, p = 0.02). Both groups seemed to have stabilized at 1 year. We found similar bone mineral density measured by DXA, and similar RSA migration in the other directions. No cups were re-revised. Interpretation - Local treatment of the allograft bone with clodronate reduced early proximal migration of the revised cup but without any measurable difference in periacetabular bone density.

Excellent long-term results of the Müller acetabular reinforcement ring in primary cup revision

Background and purpose - The original Müller acetabular reinforcement ring (ARR) was developed to be used for acetabular revisions with small cavitary and/or segmental defects or poor acetabular bone quality. Long-term data for this device are scarce. We therefore investigated long-term survival and radiographic outcome for revision total hip arthroplasty using the ARR. Patients and methods - Between October 1984 and December 2005, 259 primary acetabular revisions using an ARR were performed in 245 patients (259 hips). The mean follow-up time was 10 (0-27) years; 8 hips were lost to follow-up. The cumulative incidence for revision was calculated using a competing risk model. Radiographic assessment was performed for 90 hips with minimum 10 years' follow-up. It included evaluation of osteolysis, migration and loosening. Results - 16 ARRs were re-revised: 8 for aseptic loosening, 6 for infection, 1 for suspected infection, and 1 due to malpositioning of the cup. The cumulative re-revision rate for aseptic loosening of the ARR at 20 years was 3.7% (95% CI 1.7-6.8%). Assuming all patients lost to follow-up were revised for aseptic loosening, the re-revision rate at 20 years was 6.9% (95% CI 4.1-11%). The overall re-revision rate of the ARR for any reason at 20 years was 7.0% (95% CI 4.1-11%). 21 (23%) of the 90 radiographically examined ARR had radiographic changes: 12 showed isolated signs of osteolysis but were not loose; 9 were determined loose on follow-up, of which 5 were revised. Interpretation - Our data suggest that the long-term survival and radiographic results of the ARR in primary acetabular revision are excellent.

Favorable Early Results of Impaction Bone Grafting With Reinforcement Mesh for the Treatment of Paprosky 3B Acetabular Defects

BACKGROUND

We present the early institutional experience with the use of impaction bone grafting, mesh augmentation, and cement fixation of an all-polyethylene cup for the treatment of Paprosky 3B acetabular defects during revision total hip arthroplasty.

METHODS

Between 2005 and 2014, 21 patients (9 men, 12 women) with Paprosky 3B acetabular defects who underwent revision total hip arthroplasty using this technique were reviewed clinically and radiographically. Average age and body mass index were 72.4 (range, 48-91) years and 24.5 (range, 18.9-31) kg/m², respectively. All patients underwent revision for aseptic loosening. Surgical technique included the use of a peripheral mesh to contain the defect, followed by impaction of morselized fresh-frozen bone graft and cement fixation of a polyethylene cup.

RESULTS

Complications occurred in 6 patients (29%) including limp (2), sciatic nerve palsy that resolved (1), limb length discrepancy (1), and greater trochanteric fracture (1). After an average follow-up of 47 months (range, 13-128 months), the average Hospital for Special Surgery hip score was 35.5 (range, 20-40). Radiographic assessment revealed cephalad cup migration of 2.29 mm (range, 0-20 mm) and medial migration of 1.57 mm (range, 0-6 mm). One patient has radiographic loosening and no symptoms 120 months postoperatively. No patient returned to the operating room for a related reason or is scheduled to undergo acetabular re-revision surgery.

CONCLUSION

Impaction bone grafting is a reliable technique for the treatment of Paprosky 3B acetabular defects. It restores bone stock like no other available for addressing these defects. Longer follow-up is required to assess potential deterioration of fixation.

A cemented cup with acetabular impaction bone grafting is more cost-effective than an uncemented cup in patients under 50 years

PURPOSE

Acetabular deficiencies in young patients can be restored in several ways during total hip arthroplasty. Currently, cementless cups are most frequently used. Impaction bone grafting of acetabular defects is a more biological approach, but is it cost-effective in young patients on the long term?

METHODS

We designed a decision model for a cost-utility analysis of a cemented cup with acetabular impaction bone grafting versus an uncemented cup, in terms of cost per quality-adjusted life year (QALY) for the young adult with acetabular bone deficiency, in need for a primary total hip arthroplasty. Outcome probabilities and effectiveness were derived from the Radboud University Nijmegen Medical Centre and the Norwegian Hip Register. Multiple sensitivity analyses were used to assess the contribution of the included variables in the model's outcome.

RESULTS

Cemented cups with impaction bone grafting were more cost-effective compared to the uncemented option in terms of costs per QALY. A scenario suggesting equal primary survival rates of both cemented and uncemented cups still showed an effect gain of the cemented cup with impaction bone grafting, but at higher costs.

CONCLUSIONS

Based on this model, the first choice of treatment of the acetabular bone deficient osteoarthritic hip in a young patient is reconstruction with impaction bone grafting and a cemented cup.

Reconstruction of non-contained acetabular defects with impaction grafting, a reinforcement mesh and a cemented polyethylene acetabular component

This review summarises the technique of impaction grafting with mesh augmentation for the treatment of uncontained acetabular defects in revision hip arthroplasty.

The ideal acetabular revision should restore bone stock, use a small socket in the near-anatomic position, and provide durable fixation. Impaction bone grafting, which has been in use for over 40 years, offers the ability to achieve these goals in uncontained defects. The precepts of modern, revision impaction grafting are that the segmental or cavitary defects must be supported with a mesh; the contained cavity is filled with vigorously impacted morselised fresh-frozen allograft; and finally, acrylic cement is used to stabilise the graft and provide rigid, long-lasting fixation of the revised acetabular component.

Favourable results have been published with this technique. While having its limitations, it is a viable option to address large acetabular defects in revision arthroplasty.

Cite this article: Bone Joint J 2017;99-B(1 Supple A):25–30.

Is the size of the acetabular bone lesion a predictive factor for failure in revisions of total hip arthroplasty using an impacted allograft?

OBJECTIVE

The aim of this study was to determine the acetabular bone lesion size (in millimeters) from which impacted bone graft failure starts to occur more frequently, through simple anteroposterior hip radiographs, and whether measurement of the defect on simple radiographs maintains the same pattern in inter and intraobserver assessments.

METHODS

Thirty-eight anteroposterior pelvic-view radiographs from patients undergoing revision of an acetabular prosthesis were retrospectively analyzed and assessed. In the vertical plane, the bilacrimal line was measured in millimeters from the farthest point found on the bone edge of the acetabular osteolysis to the top edge of the cementation or of the acetabular implant in uncemented cases. The base was taken to be a line perpendicular to bilacrimal line, with the aim of eliminating any pelvic tilt effects. This measurement was named the vertical size of failure. Radiographs produced four years after the operation were analyzed to investigate any failure of the technique.

RESULTS

The graft failure rate in the study group was 26.3%. The failures occurred in cases with an initial bone defect larger than 11 mm. No cases with measurements smaller than this evolved with failure of the revision. The highest incidence of graft failure occurred in cases described as advanced according to the "Paprosky" classification.

CONCLUSION

Failure of acetabular revision arthroplasty using an impacted graft did not present any statistically significant correlation with the vertical extent of the lesion on simple anteroposterior radiographs, as a predictor of treatment failure.

The biological approach in acetabular revision surgery: impaction bone grafting and a cemented cup

Acetabular impaction bone grafting (IBG) in combination with a cemented cup in revision total hip arthroplasty (THA) is a proven and well-recognised technique which has been used in clinical practice for more than 35 years. Nowadays, with cemented prostheses tending to lose a larger part of the THA market every year in primary and revision cases, and many young surgeons being only trained in implanting uncemented prostheses, this technique is considered by many as technically demanding and time consuming, making its use less appealing. Despite this image and many new innovative techniques using uncemented implants in acetabular revisions over the last 25 years, IBG with a cemented cup is still one of the few techniques that really can reconstitute bone and respects human biology. In this era of many biologically-based breakthroughs in medicine, it is hard to explain that the solution of most orthopaedic surgeons for the extensive bone defects as frequently seen during acetabular revision surgery, consists of implanting bigger and larger metal implants. This review aims to put the IBG method into a historical perspective, to describe the surgical technique and present the clinical results.

Reconstruction of acetabulum in revision total hip arthroplasty for pelvic discontinuity: report of a difficult case requiring four revision arthroplasty

Background

Massive bone defects of the acetabulum with pelvic discontinuity are one of the major problems in revision total hip arthroplasty. Several techniques have been described for repair of acetabular defect; however, reconstruction of acetabulum with massive bone defect is still a major problem. We describe a patient who required four revision total hip arthroplasty during a 24-year period.

Findings

The acetabulum with pelvic discontinuity was successfully reconstructed by stabilization of the posterior column with a plate commonly used for fracture treatment, and stabilization of the anterior column by reinforcement device commonly used for acetabular reconstruction. Fixation of both acetabular columns provided significant improvement of component stability.

Conclusions

In the case of pelvic discontinuity with massive acetabular bone defect, reconstruction by stabilizing both acetabular columns using reconstruction plate and KT plate is one of the better surgical options.

Does cup-cage reconstruction with oversized cups provide initial stability in THA for osteoporotic acetabular fractures?

BACKGROUND

The incidence of acetabular fractures in osteoporotic patients is increasing. Immediate total hip arthroplasty (THA) has potential advantages, but achieving acetabular component stability is challenging and, at early followup, reported revision rates for loosening are high.

QUESTIONS/PURPOSES

This study measured acetabular component stability and the initial surface contact achieved between the acetabular component and unfractured region of the pelvis after THA using an oversized acetabular component and cup-cage reconstruction.

METHODS

Between November 2011 and November 2013, we treated 40 acute acetabular fractures in patients older than 70 years of age. Of these, 12 (30%) underwent immediate THA using an oversized acetabular component with screws inserted only into the ilium and a cup-cage construct. Postoperatively all patients were mobilized without weightbearing restrictions. Indications for immediate THA after acetabular fractures were displaced articular comminution deemed unreducible. Eleven of the 12 were prospectively studied to evaluate the initial stability of the reconstructions using radiostereometric analysis. One of the patients died of a pulmonary embolism after surgery, and the remaining 10 (median age, 81 years; range, 72-86 years) were studied. Of these, five were analyzed at 1 year and five were analyzed at 2 years. Acetabular component migration was defined as acceptable if less than the limits for primary THA that predict later loosening (1.76 mm of proximal migration and 2.53° of sagittal rotation). The contact surface between the acetabular component and ilium in direct continuity with the sacroiliac joint, and the ischium and pubis in direct continuity with the symphysis pubis, was measured on postoperative CT scans.

RESULTS

At 1 year the median proximal migration was 0.83 mm (range, 0.09-5.13 mm) and sagittal rotation was 1.3° (range, 0.1°-7.4°). Three of the 10 components had migration above the suggested limits for primary THA at 1 year postoperatively. The contact surface achieved at surgery between the acetabular component and pelvis ranged from 11 to 17 cm(2) (15%-27% of each component).

CONCLUSIONS

The majority of acetabular components in this cohort were stable despite the small contact surface achieved between the component and pelvic bone. Three of 10 migrated in excess of the limits that predict later loosening in primary THA but it remains to be seen whether these limits apply to this selected group of frail osteoporotic patients. We continue to use this technique routinely to treat patients with the same indications, but since the analysis of these data we have added screw fixation of the acetabular component to the ischial tuberosity and the superior pubic ramus.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

THA revisions using impaction allografting with mesh is durable for medial but not lateral acetabular defects

BACKGROUND

Most acetabular revisions are managed with cementless hemispherical or elliptical metal implants relying on bone ingrowth. Nonetheless, loss of acetabular bone stock and inability to achieve secure component fixation represent challenges in the setting of revision total hip arthroplasty. Impaction bone grafting (IBG) using allograft represents one option for treatment of this problem. However, cup migration and bone graft resorption are limitations when IBG is used for large segmental defects, and the precise role of IBG as well as the use of mesh (and the kinds of defects for which mesh does not work well) in this setting remains unknown.

QUESTIONS/PURPOSES

We therefore evaluated patients undergoing acetabular revision surgery using IBG and a cemented cup in large bone defects to determine (1) the frequency with which the hip center could be restored in hips with Paprosky 3A and 3B defects and in hips with or without the use of metallic mesh during surgery; (2) survivorship of IBG acetabular-revision reconstructions in patients with severe Paprosky 3A and 3B defects; and (3) risk factors for failure of the reconstruction, including the use of mesh and defect severity (3A versus 3B).

METHODS

Between 1997 and 2009, we performed 226 acetabular revisions using IBG. During that time, indications for using IBG in this setting included Paprosky 3A and 3B defects without pelvic discontinuity. Of these, 204 (90.2%) were available for followup at a minimum of 5 years (mean, 10 years; range, 5-17 years). There were 100 hips with an intraoperative bone defect of Paprosky 3A and 104 with a 3B. Medial or rim acetabular uncontained defects were treated with medial and/or lateral metallic mesh in 142 hips. We determined the postoperative radiological cup position and acetabular reconstruction of the hip center according to Ranawat in both groups. We assessed the appearance of cup loosening and the possible risk factors with regression analysis.

RESULTS

Mean postoperative acetabular abduction angle and vertical, horizontal, and hip rotation center distances improved (p < 0.001 in all parameters). Nine hips showed radiological loosening in the group with bone defect 3A and 16 in Group 3B. The survival rate for loosening at 15 years was 83% (95% confidence interval [CI], 71%-95%) for Group 3A and 73% (95% CI, 60%-84%) for Group 3B (p = 0.04). The survivorship for loosening when using mesh or not at 15 years was: no mesh 89% (95% CI, 74%-99%), medial mesh 85% (95% CI, 72%-97%), lateral mesh 80% (95% CI, 67%-91%), and medial and lateral meshes 54% (95% CI, 31%-76%) (p = 0.008). After controlling the most relevant confounding variables we found that the most important factor associated with loosening was lateral mesh use (p = 0.008; hazard ratio, 2.942; 95% CI, 1.328-6.516).

CONCLUSIONS

IBG provides an improvement in reconstruction of the hip rotation center in acetabular revision surgery. Although results are good for contained or medial large defects, hips with a rim or lateral segmental defect may need other options for reconstruction of these challenging surgeries.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Acetabular revision with impaction bone grafting and a cemented polyethylene acetabular component

We present the results of 62 consecutive acetabular revisions using impaction bone grafting and a cemented polyethylene acetabular component in 58 patients (13 men and 45 women) after a mean follow-up of 27 years (25 to 30). All patients were prospectively followed. The mean age at revision was 59.2 years (23 to 82).

We performed Kaplan–Meier (KM) analysis and also a Competing Risk (CR) analysis because with long-term follow-up, the presence of a competing event (i.e. death) prevents the occurrence of the endpoint of re-revision.

A total of 48 patients (52 hips) had died or had been re-revised at final review in March 2011. None of the deaths were related to the surgery. The mean Harris hip score of the ten surviving hips in ten patients was 76 points (45 to 99).

The KM survivorship at 25 years for the endpoint ‘re-revision for any reason’ was 58.0% (95% confidence interval (CI) 38 to 73) and for ‘re-revision for aseptic loosening’ 72.1% (95% CI 51 to 85). With the CR analysis we calculated the KM analysis overestimates the failure rate with respectively 74% and 93% for these endpoints. The current study shows that acetabular impaction bone grafting revisions provide good clinical results at over 25 years.

Cite this article: Bone Joint J 2015;97-B:1338–44.

Fate of bone grafting for acetabular defects in total hip replacement

BACKGROUND

The use of allografts and autografts in the management of acetabular defects have been reported with varying results. Trabecular metal is an expensive option in the management of these defects. This study aims to assess the fate and efficacy of bone grafting for acetabular bone defects in total hip arthroplasty.

MATERIALS AND METHODS

A total of 30 hips in 28 patients with acetabular deficiencies were treated with bone grafting and total hip replacement (THR). Seventeen hips had American Academy of Orthopedic Surgeons (AAOS) type 2 (Paprosky type 2c) deficiency and 13 had AAOS type 3 (Paprosky type 3a) defects of the acetabulum. Allografts were used in 15 patients and autografts were used in the remaining 13. Cemented total hip arthroplasty was done in 18 hips and uncemented THR in 12. Seven patients underwent the procedure for, acetabular erosion and symptoms following hemiarthroplasty (4 out of 7), or, acetabular revision for failure (3 out of 7) following total hip arthroplasty. Acetabular deficiencies in other patients were due to posttraumatic causes, advanced primary hip arthritis and second stage treatment of postinfective arthritis. A mesh was used in 6 hips and screws were used in 13 hips for graft fixation.

RESULTS

Patients were followed up clinicoradiologically for a period of 10 months to 4 years (mean 23.4 months). One patient required staged revision due to infection. Two patients had early asymptomatic cup migration. One patient had graft lysis and change in cup inclination with persistent pain. He was not keen on further intervention at last followup. Other patients were pain free at the time of followup with radiographs showing maintenance of graft and implant position.

CONCLUSION

Bone grafting is a suitable option in the management of acetabular defects in total hip arthroplasty, especially in resource challenged countries.

Acetabular reconstruction with impaction bone grafting and cemented polyethylene socket in total hip revision arthroplasty

Background and aims:

Bone deficiency in revision total hip arthroplasty is a challenge to the surgeon. One option for restoration of the bone stock is impaction bone grafting and use of a cemented socket. The aim of this study was to evaluate the mid-term clinical outcome of impaction bone grafting and cemented socket revisions.

Material and methods:

A total of 59 patients (60 hips) underwent revision arthroplasty with impaction bone grafting and application of a cemented socket on the acetabular side in the Turku University Hospital from 1999 to 2004. The study end-point was re-revision for any reason. The cumulative percentages for survival were followed and estimated with Kaplan–Meier curves. Associations between occurrence of re-revision and potential risk factors were analyzed with logistic regression. Results were quantified by odd ratios and 95% confidence intervals. The mean age of the patients was 69 years (33% male). A total of 3% of the patients had a class I Paprosky acetabular defect, 38% had class II, and 55% had class III.

Results:

The overall survival rate was 73%. The mean follow-up time was 7 years. The most common reason for re-revision was aseptic loosening of the acetabular component (13 patients, 81% of re-revisions). Cox’s regression analysis did not identify any risk factors for re-revision.

Conclusion:

Our results were inferior compared to some previous studies. Impaction bone grafting of acetabular defects in revision total hip arthroplasty may not always provide a reliable bone stock in long-term.

Massive bone defect compromises postoperative cup survivorship of acetabular revision hip arthroplasty with impaction bone grafting

We evaluated 66 acetabular revision arthroplasties using cemented cup with impaction bone grafting (IBG) to detect the extent that bone defect affects the outcome. We defined the maximum acetabular defect distance (MADD), which indicates the greatest depth of the grafted layer. Cup survival analysis with aseptic loosening as the endpoint revealed that the "MADD≤20mm" group showed higher survivorship than the "MADD>20mm" group (95% vs. 74%, P=0.034), and that the simple-wall-defect group (none or one mesh used) showed higher survivorship than the complex-wall-defect group (two meshes used) (96% vs. 73%, P=0.044). A favorable indication for acetabular IBG reconstruction is cases in which those cups can be placed at≤20mm MADD with a simple wall defect.

Bone defect determines acetabular revision surgery

Cup revision can be a highly complex operation depending on the bone defect. In acetabular defects of less than 30% (Paprosky types 1 and 2), porous hemispherical cementless cups fixed with screws give good results. Modern trabecular metal designs improve these good results. Morsellised allografts are useful for filling cavitary defects. In acetabular defects greater than 30% (Paprosky types 3A and 3B), impacted morsellised allografts with a cemented cup technique produce good results. Difficult cases with pelvic discontinuity require reconstruction of the acetabulum with acetabular plates or large cup-cages to solve these difficult problems.

Clinical and radiographic outcomes of acetabular impaction grafting without cage reinforcement for revision hip replacement: a minimum ten-year follow-up study

Impaction bone grafting for the reconstitution of bone stock in revision hip surgery has been used for nearly 30 years. Between 1995 and 2001 we used this technique in acetabular reconstruction, in combination with a cemented component, in 304 hips in 292 patients revised for aseptic loosening. The only additional supports used were stainless steel meshes placed against the medial wall or laterally around the acetabular rim to contain the graft. All Paprosky grades of defect were included. Clinical and radiographic outcomes were collected in surviving patients at a minimum of ten years after the index operation. Mean follow-up was 12.4 years (sd 1.5) (10.0 to 16.0). Kaplan-Meier survival with revision for aseptic loosening as the endpoint was 85.9% (95% CI 81.0 to 90.8) at 13.5 years. Clinical scores for pain relief remained satisfactory, and there was no difference in clinical scores between cups that appeared stable and those that appeared radiologically loose.

Reconstruction of massive uncontained acetabular defects using allograft with cage or ring reinforcement

We retrospectively reviewed 44 consecutive patients (50 hips) who underwent acetabular re-revision after a failed previous revision that had been performed using structural or morcellised allograft bone, with a cage or ring for uncontained defects. Of the 50 previous revisions, 41 cages and nine rings were used with allografts for 14 minor-column and 36 major-column defects. We routinely assessed the size of the acetabular bone defect at the time of revision and re-revision surgery. This allowed us to assess whether host bone stock was restored. We also assessed the outcome of re-revision surgery in these circumstances by means of radiological characteristics, rates of failure and modes of failure. We subsequently investigated the factors that may affect the potential for the restoration of bone stock and the durability of the re-revision reconstruction using multivariate analysis.

At the time of re-revision, there were ten host acetabula with no significant defects, 14 with contained defects, nine with minor-column, seven with major-column defects and ten with pelvic discontinuity. When bone defects at re-revision were compared with those at the previous revision, there was restoration of bone stock in 31 hips, deterioration of bone stock in nine and remained unchanged in ten. This was a significant improvement (p <  0.001). Morselised allografting at the index revision was not associated with the restoration of bone stock.

In 17 hips (34%), re-revision was possible using a simple acetabular component without allograft, augments, rings or cages. There were 47 patients with a mean follow-up of 70 months (6 to 146) available for survival analysis. Within this group, the successful cases had a minimum follow-up of two years after re-revision. There were 22 clinical or radiological failures (46.7%), 18 of which were due to aseptic loosening. The five and ten year Kaplan–Meier survival rate was 75% (95% CI, 60 to 86) and 56% (95% CI, 40 to 70) respectively with aseptic loosening as the endpoint. The rate of aseptic loosening was higher for hips with pelvic discontinuity (p = 0.049) and less when the allograft had been in place for longer periods (p = 0.040).

The use of a cage or ring over structural allograft bone for massive uncontained defects in acetabular revision can restore host bone stock and facilitate subsequent re-revision surgery to a certain extent.

Cite this article: Bone Joint J 2014;96-B:319–24.

Supercharging irradiated allografts with mesenchymal stem cells improves acetabular bone grafting in revision arthroplasty

PURPOSE

The procedure of bone allografting associated with a reinforcement device is widely used for acetabulum revision. However in absence of biologic fixation of the allograft, failure of the reconstruction may occur. We made the hypothesis that it would be possible to load these grafts with bone marrow derived mesenchymal stem cells (MSC) to rescue the osteogenic capacity of an allogenic dead bone and therefore enhance incorporation of allografts with the host bone and decrease the number of failures related to the allograft.

METHOD

We identified 60 patients who had undergone acetabular component revision for aseptic failure of cemented implants associated with massive periacetabular osteolysis and Paprosky type 3A or 3B classification (without pelvic discontinuity) between 1996 and 2001. The study group of 30 patients received MSCs in the allograft and at the host graft junction. The average total number of MSCs received by each patient was 195,000 cells (range 86,000-254,000 cells). The control group of 30 patients had no MSCs in the allograft. Patients were matched for the size of periacetabular osteolysis (Paprosky type 3A or 3B). We compared the evolution of the allografts and evaluated cup migration and revision of the hips as end points at a minimum of 12 years or until failure.

RESULT

Better radiographic graft union rates and less allograft resorption were observed with allografts loaded with stem cells. Allograft resorption was significantly decreased in the group with allograft loaded with MSCs (1.2 cm(2) -range 0-2.3 cm(2)-of resorption on radiographs in the group with MSCs; versus 6 cm(2), range 2.1-8.5 cm(2) in the group without MSCs). The rate of mechanical failure was highest (p = 0.01) among the 30 patients with allograft without stem cells (9/30; 30 %) compared with no failures for patients with allograft loaded with stem cells. Revision of the cup was necessary in nine patients in the control group. No revision was performed in the 30 patients of the study group with MSCs.

CONCLUSION

For acetabular defect reconstruction, loading the allograft with MSCs has resulted in a lower rate of failure as compared with allograft without MSCs.

Method of fixation does not influence the overall risk of rerevision in first-time cup revisions

BACKGROUND

During the last two decades, uncemented fixation has been increasingly preferred worldwide during cup revision surgery. In Sweden, the number of uncemented cup revisions has been increasing during the last decade. However, it is unclear whether the risk of rerevision differs between cemented and uncemented cups.

QUESTION/PURPOSES

We determined (1) the risk of rerevision after cemented and uncemented fixation; (2) the influence of concomitant stem revision on the risk of rerevision of the cup; (3) the difference in risk of rerevision of an uncemented cup revision compared with liner revision only; and (4) whether the surgical incision influenced the risk of rerevision.

METHODS

Between 1979 and 2010, 19,342 first-time cup revisions were reported to the Swedish Hip Arthroplasty Register. From these, 749 were excluded (hip resurfacing, cases with tumor diagnoses, and missing data) leaving 18,593 (73% cemented) for further analysis. We used a Cox regression model adjusted for age, sex, primary diagnosis, method of fixation, concomitant stem revision, and cemented/uncemented fixation to assess risk of rerevision.

RESULTS

The relative risk for rerevision for any reason did not differ between cemented and uncemented fixation (relative risk [RR], 0.94). If the stem was not revised at index revision, the risk of further cup revision increased twofold (RR, 1.91). Liner revisions were associated with a 70% increased risk for rerevision of the cup as a result of any reason and especially because of dislocation (RR, 2.94). The surgical incision did not influence the overall risk for rerevision (direct lateral/posterolateral: RR, 1.02) or the risk of rerevision resulting from dislocation (RR, 0.91).

CONCLUSIONS

We found no difference in the overall risk of rerevision between cemented and uncemented fixation. Liner exchange had a higher risk for rerevision when compared with cases being rerevised with a new uncemented cup.

Acetabular impaction bone grafting in total hip replacement

The increasing need for total hip replacement (THR) in an ageing population will inevitably generate a larger number of revision procedures. The difficulties encountered in dealing with the bone deficient acetabulum are amongst the greatest challenges in hip surgery. The failed acetabular component requires reconstruction to restore the hip centre and improve joint biomechanics. Impaction bone grafting is successful in achieving acetabular reconstruction using both cemented and cementless techniques. Bone graft incorporation restores bone stock whilst providing good component stability. We provide a summary of the evidence and current literature regarding impaction bone grafting using both cemented and cementless techniques in revision THR.

Cite this article: Bone Joint J 2013;95-B, Supple A:98–102.

Systematic review on outcomes of acetabular revisions with highly-porous metals

PURPOSE

The purpose of this study was to systematically review the literature and report the clinical and radiographic outcomes of highly-porous acetabular cups in revision settings.

METHOD

A literature search of four electronic databases of EMBASE, CINAHL-plus, PubMed, and SCOPUS yielded 25 studies reporting the outcomes of 2,083 revision procedures with highly-porous acetabular components. There was lack of high quality evidence (level I and level II studies) and only two studies with level III evidence, while the remainder were all level IV studies. In addition, a majority of the studies had small sample sizes and had short to mid-term follow-up. The mean age of the patients was 65 years (range, 58-72 years) and the mean follow-up was 3.6 years (range, two to six years). Outcomes evaluated were aseptic survivorship, Harris hip scores, migration rates, incidence of peri-acetabular radiolucencies and radiographic restoration of the hip centre.

RESULTS

The mean aseptic survivorship was 97.2% (range, 80-100%). The Harris hip scores improved from a mean pre-operative score of 42 points, (range, 29-75 points), to a mean postoperative score of 79 points (range, 69-94 points). The mean incidence of cup migration and prevalence of peri-acetabular radiolucencies was 2.4% (range, 0-8.8%) and 4.6% (range, 0-19%), respectively, at final follow-up. The vertical hip centre-of-rotation was restored significantly from a mean of 39.2 mm (range, 27.6-50 mm) pre-operatively, to a mean of 24.1 mm (range, 7.4-47 mm), postoperatively.

CONCLUSION

The short-term clinical and radiographic results of highly-porous metals in revision hip arthroplasty are excellent with a low rate of loosening in the presence of both major and minor bone loss.

The results of acetabular impaction grafting in 129 primary cemented total hip arthroplasties

Between 1995 and 2003, 129 cemented primary THAs were performed using full acetabular impaction grafting to reconstruct acetabular deficiencies. These were classified as cavitary in 74 and segmental in 55 hips. Eighty-one patients were reviewed at mean 9.1 (6.2-14.3) years post-operatively. There were seven acetabular component revisions due to aseptic loosening, and a further 11 cases that had migrated >5mm or tilted >5° on radiological review - ten of which reported no symptoms. Kaplan-Meier analysis of revisions for aseptic loosening demonstrates 100% survival at nine years for cavitary defects compared to 82.6% for segmental defects. Our results suggest that the medium-term survival of this technique is excellent when used for purely cavitary defects but less predictable when used with large rim meshes in segmental defects.

Acetabular cup positioning in revision total hip arthroplasty with Paprosky type III acetabular defects: Martell radiographic analysis

PURPOSE

This study evaluates acetabular cup position in the setting of revision total hip arthroplasty (THA) with severe acetabular bone defects.

METHODS

With a definition of safe zone of abduction (30-50°) and anteversion (5-25°), acetabular cup position was measured by a digital image analysis program for 34 patients with Paprosky type III acetabular bone defects.

RESULTS

There were 24 cups (71%) for abduction and 26 cups (76%) for anteversion located in the safe zone. Nineteen cups (56%) were within the safe zone for both abduction and anteversion. There was no dislocation, however one cup out of the safe zone resulted in early cup failure due to aseptic loosening.

CONCLUSIONS

The acetabular cup positioning in patients with Paprosky type III defects was 'optimal' in half of the cases. The prevalence of optimal acetabular cup position was similar to those reported in primary THA, suggesting that the presence of a large acetabular bone defect may not be a significant risk factor for suboptimal acetabular cup positioning in the setting of revision THA.