Acetabular reconstruction with morcellized allograft and ring support: a medium-term review

Periprosthetic acetabular fractures as a complication of total hip arthroplasty

Periprosthetic acetabular fractures are rare but potentially devastating complications of total hip arthroplasty. As the number of total hip arthroplasties performed annually increases, so has the incidence of periprosthetic fractures, with the topic being spotlighted more frequently in the orthopaedic community. There is a particular sparsity of literature regarding periprosthetic acetabular fractures, with periprosthetic femoral fractures after total hip arthroplasty being traditionally far more commonly reported. This article aims to provide an up-to-date review of the epidemiology, risk factors, diagnostic challenges, classifications, and management strategies for periprosthetic acetabular fractures after total hip arthroplasty.

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.

Clinical study of outcomes after revision surgery using porous titanium custom-made implants for severe acetabular septic bone defects

PURPOSE

Acetabular bone loss is a challenging problem in revision total hip arthroplasty (rTHA). Severe bone loss is not uncommon especially in periprosthetic joint infection. Surgical options, including revision shells, rings, and cages-with or without bone allograft-are affected by high complication rates and unsatisfactory clinical results. We report our mid-term results of non-flanged, custom-made acetabular components in staged rTHA.

METHODS

We retrospectively reviewed all patients undergoing two-stage revision with acetabular custom-made implants between 2014 and 2016 at a single institution. Harris Hip Scores, Oxford Hip Scores, and Visual Analogue Scales for pain were obtained, and radiographical follow-up was performed. Complications were reported and analysed.

RESULTS

We included 19 patients (19 hips) with an average follow-up of 42.3 ± 11.8 months. At the time of re-implantation, significant acetabular bone loss according to Paprosky classification (IIC, IIIA-B, and pelvic discontinuity) was detected in our patients. Clinical outcomes showed statistically significant improvement from pre-operative visit to last follow-up (p < 0.01). All custom-made implants had radiological osseointegration, and we did not find any implant complications, such as loosening or malposition. No mismatch between pre-operative planning and intra-operative findings was observed. To date, we report one septic failure managed with second staged revision, and one re-operation for recurrent THA dislocation.

CONCLUSIONS

Custom-made acetabular implants showed excellent clinical and radiographic mid-term outcomes with a low rate of related complications, providing implant stability on residual host bone, restoring hip biomechanics, and allowing biological osseointegration. Further long-term studies are needed to confirm preliminary results.

Acetabular custom-made implants for severe acetabular bone defect in revision total hip arthroplasty: a systematic review of the literature

PURPOSE

The management of acetabular bone loss is a challenging problem in revision total hip arthroplasty (rTHA). The aim of this systematic review is to summarize and critically analyze indications, complications, clinical and radiological outcomes of custom-made acetabular components in rTHA.

METHODS

A systematic review of English literature was performed on Medline. Retrospective or prospective studies with minimum 2 years of follow-up (FU) were included. The PRISMA 2009 flowchart and checklist were considered to edit the review. Rates of intra- or post-operative complications, aseptic loosening (AL), periprosthetic joint infection (PJI), reoperations and re-revisions rates were extrapolated.

RESULTS

18 articles with a level of evidence of IV were included. Six hundred and thirty-four acetabular custom components (627 patients) with a mean FU of 58.6 ± 29.8 months were analyzed. The studies showed good clinical and functional outcomes. Custom-made acetabular components allowed a stable fixation with 94.0 ± 5.0% survival rate. The estimated rate of re-operations and re-revisions were 19.3 ± 17.3% and 5.2 ± 4.7%, respectively. The incidence of PJI was 4.0 ± 3.9%.

CONCLUSIONS

The acetabular custom-made implants represent a reliable solution for pelvic discontinuity and particular cases of bone loss classified as Paprosky Type IIIA-B or type III-IV according to American Academy of Orthopaedic Surgeons system where the feature of the defect cannot be handled with standard implants. This strategy allows to fit the implant to the residual host bone, bypassing the bony deficiency and restoring hip biomechanics. Satisfactory clinical and radiological outcomes at mid-term follow-up are reported in literature.

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.

Custom Triflange Acetabular Components for Large Acetabular Defects: Minimum 10-Year Follow-up

Compromise of bony support presents a difficult problem in acetabular revision surgery. Although various methods have been proposed to cope with this problem, they have had variable results and little long-term follow-up. The authors reviewed the results of 37 patients undergoing custom triflange revision surgery. Two patients were lost to follow-up, leaving 35 patients with minimum 10-year clinical and radiographic follow-up. Thirty-two (91%) of 35 components were unrevised and functioning well at minimum 10-year follow-up. One component placed for pelvic discontinuity loosened at 12 years after surgery but was converted to a conventional total hip. One component had failure of 3 ischial screws at 6 months; however, at 11 years, the patient had no additional clinical or radiographic evidence of loosening. The average Harris hip score was 28 preoperatively and 90 postoperatively. Two components (6%) were removed for infection. There were no dislocations, fractures, or nerve injuries. Revision of large acetabular defects with a custom triflange component resulted in reliably good to excellent results at minimum 10-year follow-up. [Orthopedics. 2018; 41(3):e316-e320.].

Major acetabular defects treated with the Burch-Schneider antiprotrusion cage and impaction bone allograft in a large series: a 5- to 7- year follow-up study

INTRODUCTION

Major bone defects are the greatest challenge in hip revision arthroplasty.

METHODS

In a prospective, consecutive nonrandomised study we followed up 74 patients with Type III (AAOS) acetabular bone defects who underwent revision hip arthroplasty with bone grafting and implantation of a Burch-Schneider anti-protrusion cage (APC). The patients were examined pre- and postoperatively according to a standardised clinical and radiological protocol. No patient was lost to follow-up.

RESULTS

9 patients died before follow-up. In 9 other patients the APC was revised within the follow-up period. In 4 of these patients the revision was necessary because of aseptic loosening. In the remaining 5 cases joint infection, recurrent dislocation and 1 trauma were the reasons for revision. 56 patients were included in the statistical analysis. In the follow-up group the mean Harris Hip Score increased from 39.9 preoperatively to 73.2. 85% of the patients assessed their operation result as good or excellent.

CONCLUSIONS

In a large consecutive series the Burch-Schneider anti-protrusion cage proved to be a valuable option in the treatment of major acetabular bone defects in hip revision surgery.

Custom Acetabular Cages Offer Stable Fixation and Improved Hip Scores for Revision THA With Severe Bone Defects

BACKGROUND

Revision THA is particularly challenging in hips with severe acetabular bone loss. When the extent or geometry of the acetabular bone loss precludes more-straightforward techniques such as jumbo hemispheric cementless shells, reconstruction with morselized allograft protected by a custom cage may offer an alternative, but, to our knowledge, few series have reported on results with this approach.

QUESTIONS/PURPOSES

For patients with severe (Paprosky IIIB) defects, we asked: do individualized custom cages result in (1) improved Harris hip scores; (2) restoration of hip center; and (3) a low incidence of surgical complications?

METHODS

Twenty-six patients (26 hips) with a massive acetabular defect were involved in this study from 2003 to 2013. During this period, one patient was lost to followup and one died, leaving 24 patients (eight males, 16 females) in this retrospective analysis. The customized cages were individualized to each patient's bone defect based on rapid-prototype three-dimensional printed models. Mean followup was 67 months (range, 24-120 months). Harris hip scores were assessed before surgery and at each followup. Postoperative radiographs were evaluated for cage position, migration, and graft incorporation. Complications and reoperations were assessed by chart review.

RESULTS

The mean Harris hip score improved from 36 (SD, 8; range, 20-49) to 82 (SD, 18; range, 60-96) (p < 0.001). Individualized custom cages resulted in generally reliable restoration of the hip center. No rerevisions have been performed. None of the cups showed radiographic migration, but one cage was believed to be loose, based on a circumferential 2-mm radiolucent line. Cancellous allografts appeared to be incorporated in 23 of 24 patients. One deep infection and one superficial infection were observed and treated with irrigation, débridement, and vacuum-sealing drainage. One dislocation and one suspected injury of the superior gluteal nerve also were observed and treated conservatively.

CONCLUSIONS

Individualized custom cages using rapid prototyping and three-dimensional printing appeared to provide stable fixation and improved hip scores at short-term followup in this small, single-center series. As further improvements in the design and manufacturing process are made, future studies should evaluate larger patient groups for longer times, and, ideally, compare this approach with alternatives for these complex bone defects.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Clinical evaluation and surgical options in acetabular reconstruction: A literature review

The purpose of this paper is to review the clinical indications for acetabular reconstruction in patients with underlying peri-prosthetic segmental and cavitary defects, evaluate steps in pre-operative planning, and present the American Academy of Orthopaedic Surgeons (AAOS) and Paprosky classification systems to categorize acetabular defects. We also present a review of the current surgical techniques to reconstruct the acetabular socket which includes a cementless acetabular component with morselized bone, structural allograft, jumbo and oblong cups, reinforcement rings, bone cages, custom triflange acetabular constructs, and trabecular metal components.

Acetabular Reconstruction with Reinforcement Ring and Morsellised Graft: Technique and Medium-term Result

Background

Acetabular bone defects are commonly seen in both primary and secondary total hip arthroplasty, creating difficulties in restoring anatomical hip centres, which results in high mechanical failure rate.

Methods

Total hip arthroplasty with acetabular reinforcement rings were performed in 18 hips in 18 patients from 1996 to 2011 in United Christian Hospital. Both clinical and radiographical assessment were performed during follow-up.

Results

Eight patients died of unrelated diseases with average follow-up of 30.5 months. At the latest follow-up, none of them showed radiographic signs of loosening or migration of implants and none of them required revision surgery. The remaining 10 patients with mean age of 77.9 years (range, 65–88] at the time of operation were followed-up for an average of 67.4 months (range, 11–121). The average Harris hip score was 78.3 (range, 58.5–87). The average vertical and horizontal difference of hip centres was 1.5 mm superiorly ( p = 0.431) and 0.4 mm medially ( p = 0.619) respectively when postoperative hip centres were compared to their contralateral hips. The average inclination of the polyethylene cup was 47.8 degrees (range, 42–58). There was no evidence of radiographic loosening during our follow-up and none of them required revision surgery.

Conclusion

Acetabular reconstruction with the use of acetabular reinforcement rings and morsellised bone grafts showed satisfactory clinical and radiographic results at a medium-term follow-up.

Options for managing severe acetabular bone loss in revision hip arthroplasty. A systematic review

Revision hip arthroplasty in the presence of severe acetabular bone loss is challenging and requires a solid understanding of current techniques. A literature search of multiple databases applying specific criteria revealed a total of 50 articles of level IV scientific evidence comprising 2415 patients (2480 hips) managed with reinforcement devices (roof-reinforcement rings and anti-protrusio cages), custom-made triflanged acetabular components (CTACs), jumbo cups and tantalum metal (TM) systems. Overall, patients had improved postoperative hip scores for each technique. The use of reinforcement devices resulted in a mean revision rate of 8.2% and a mean complication rate of 29.21%. CTACs were associated with a revision rate of 15.9% and had a complication rate of 24.5%. Jumbo cups were revised in 8.8% of patients and had a complication rate of 18.4%. TM systems had an overall revision rate of 8.5% with complications seen in 18.5% of patients. CTACs had considerably higher revision rates compared to the other techniques. Jumbo cups and TM systems had lower complication rates compared to the use of reinforcement devices and CTACs. The most frequently occurring complications seen throughout the series were aseptic loosening, dislocation and infection.

Acetabular reconstruction with the Burch-Schneider antiprotrusio cage and bulk allografts: minimum 10-year follow-up results

Reconstruction of severe pelvic bone loss is a challenging problem in hip revision surgery. Between January 1992 and December 2000, 97 hips with periprosthetic osteolysis underwent acetabular revision using bulk allografts and the Burch-Schneider antiprotrusio cage (APC). Twenty-nine patients (32 implants) died for unrelated causes without additional surgery. Sixty-five hips were available for clinical and radiographic assessment at an average follow-up of 14.6 years (range, 10.0 to 18.9 years). There were 16 male and 49 female patients, aged from 29 to 83 (median, 60 years), with Paprosky IIIA (27 cases) and IIIB (38 cases) acetabular bone defects. Nine cages required rerevision because of infection (3), aseptic loosening (5), and flange breakage (1). The average Harris hip score improved from 33.1 points preoperatively to 75.6 points at follow-up (P < 0.001). Radiographically, graft incorporation and cage stability were detected in 48 and 52 hips, respectively. The cumulative survival rates at 18.9 years with removal for any reason or X-ray migration of the cage and aseptic or radiographic loosening as the end points were 80.0% and 84.6%, respectively. The use of the Burch-Schneider APC and massive allografts is an effective technique for the reconstructive treatment of extensive acetabular bone loss with long-lasting survival.

Revision of complex acetabular defects using cages with the aid of rapid prototyping

This study details a method using rapid prototyping (RP) technique to assist in acetabular revision with complex bone defects. Hemi-pelvic RP models were built among 25 patients with complex acetabular bone defects. Each patient was scheduled to undergo revision using either commercially available or customized cages based on individualized RP models. Average follow-up was 4.4 years (range, 1 to 9 years). The average Harris hip score was 36.1 (range, 20 to 58) preoperatively and reached an average of 82.6 (range, 60-96) at the last follow-up. No mechanical failure or loosening was observed. One patient experienced hip dislocation 4 days postoperatively. The resultant findings of this study merit consideration of RP as a helpful clinical complement for dealing with some complex bone defect of acetabulum.

Revision with impacted bone allografts and the Kerboull cross plate for massive bone defect of the acetabulum

We retrospectively reviewed 31 hips with massive bone defect because of aseptic loosening of the acetabulum treated with impacted bone allografts with the Kerboull-type acetabular device. Mean age at surgery was 67.9 years, and mean duration of follow-up was 6.3 years. Thickness of the bone graft was evaluated by postoperative radiography. Seven hips showed radiological failure associated with 6 breakages of the device, and 24 hips showed stability on follow-up radiographs. Of the 13 hips showing a bone graft thickness of greater than 20 mm on follow-up radiographs, 7 were classified as failure group. If an acetabular reinforcement device with a bone graft of more than 20 mm thickness is necessary, then a structural allograft should be considered in the weight-bearing area of the support ring in addition to the morselized bone graft.

[Acetabular reinforcement rings in revision total hip arthroplasty: midterm results in 298 cases]

BACKGROUND

Acetabular revision in total hip arthroplasty (THA), especially for loose or migrated cup components with collateral bone loss, remains a great surgical challenge. The aim should always be a functionally favorable reconstruction of the rotation center with sufficient load capacity of the acetabulum. Commonly used implants in Europe are the Mueller ring, the Ganz ring, and the Burch-Schneider cage.

PATIENTS AND METHODS

We report our results of 298 patients (298 hips) with a median follow-up period of 4 (range 0-17) years in a retrospective series.

RESULTS

Follow-up data were available in 224 cases (75%). A radiographic examination was performed in 176 (59%) patients. Another 54 patients (18%) had died in the follow-up period, while another three patients (1%) were lost to follow-up. Eighteen patients (16%) underwent re-revision, in nine cases for aseptic loosening and in the remaining nine cases for infection. In seven additional cases (2%), radiological and clinical failure was found during follow-up. The overall survival rate was 94% at 5 years and 89% at 8 years.

CONCLUSION

Revision THA using acetabular reinforcement rings results in acceptable midterm results. However, septic complications and lysis of the bone graft with consecutive failure of the reinforcement ring remain problematic.

The survival of support rings in complex acetabular revision surgery

Between 1980 and 2000, 63 support rings were used in the management of acetabular deficiency in a series of 60 patients, with a mean follow-up of 8.75 years (2 months to 23.8 years). There was a minimum five-year follow-up for successful reconstructions. The indication for revision surgery was aseptic loosening in 30 cases and infection in 33. All cases were Paprosky III defects; IIIA in 33 patients (52.4%) and IIIB in 30 (47.6%), including four with pelvic dissociation. A total of 26 patients (43.3%) have died since surgery, and 34 (56.7%) remain under clinical review. With acetabular revision for infection or aseptic loosening as the definition of failure, we report success in 53 (84%) of the reconstructions. A total of 12 failures (19%) required further surgery, four (6.3%) for aseptic loosening of the acetabular construct, six (9.5%) for recurrent infection and two (3.2%) for recurrent dislocation requiring captive components. Complications, seen in 11 patients (18.3%), included six femoral or sciatic neuropraxias which all resolved, one grade III heterotopic ossification, one on-table acetabular revision for instability, and three early post-operative dislocations managed by manipulation under anaesthesia, with no further instability.

We recommend support rings and morcellised bone graft for significant acetabular bone deficiency that cannot be reconstructed using mesh.

Technical factors affecting cup stability in bone impaction grafting

Favourable long-term clinical results can be achieved by the bone impaction technique in bone stock deficient acetabuli. Originally, firm impaction of manually prepared bone grafts using a rongeur was performed. An alternative technique for producing bone grafts is reaming from the pelvic wall or femoral head, which produces smaller-sized slurry bone grafts. These slurry grafts can be manually compressed in the bone defect using an acetabular reamer en reverse. In an artificial acetabular cavitary defect model both reconstruction techniques were compared in combination with a cemented cup. Mechanical testing was performed with a sequentially increasing dynamic load. Roentgen stereophotogrammetric analysis was used to determine initial cup stability. At all testing levels the initial stability of the cups reconstructed with slurry grafts and reversed reaming was significantly less in comparison to the original impaction technique. The original technique with firm impaction with a hammer and impactors of relatively large-sized bone grafts provides optimal initial stability. The reversed reaming technique of slurry grafts cannot be recommended for bone grafting of acetabular defects.

Acetabular reconstruction in revision hip surgery using femoral head block allograft

This prospective study analyzed the clinical and radiological results of 140 consecutive cases of acetabular revision using large frozen femoral head allografts and cemented all-polyethylene acetabular components. Mean follow-up was 10 years (range: 5-16 years). Thirty patients died, seven were lost to follow-up, and 26 had failed and undergone further surgery. Nineteen failures were due to aseptic failure and collapse of the graft. Kaplan-Meier survival analysis calculated a mean survival at 10 years of 88.5% for revision for any reason. We compared all reported techniques of acetabular reconstruction for similar defects and recommend a surgical strategy based on the available evidence, but weighted towards a preference to reconstitute bone stock rather than removing further bone in the revision situation.

Acetabular revision with a modular anti-protrusio acetabular component

Current anti-protrusio cages are non-porous-coated and 1 piece and they require liner cementation. These factors limit bone ingrowth, trials, and modularity. Results of a completely modular porous-coated anti-protrusio component (MAPC) are presented. Sixty-three acetabular revisions with MAPC were performed from 1998-2001 by 2 surgeons. Average follow-up was 29 months (range, 24-50). 30/63 (48%) had Paprosky type 3A or B defects. 55/63 (87%) MAPCs remain in place. Four components were removed for infection, 3 for loosening, and 1 for malposition. Eight hips dislocated, requiring 6 reoperations. Two MAPCs are radiographically loose but asymptomatic. At short-term follow-up, these results are comparable to conventional 1-piece anti-protrusio cages. Advantages include the potential for bone ingrowth and long-term fixation, surgical technique similar to large hemispherical components, ability to trial, and modularity.

Bone transplantation

Bony deficiency, particularly loss of bone stock associated with failed joint replacements or tumours, is a challenging problem in orthopaedic surgery. Bone transplantation techniques provide solutions that can be tailored to the clinical problem. However, the risks of bone transplantation are well documented and the biology of allograft incorporation remains unpredictable and poorly understood.

Wear and periprosthetic osteolysis: the problem

The dominant long-term problem in total hip replacement surgery, and an important problem in total knee replacement surgery, is wear of the polyethylene and its resulting periprosthetic osteolysis. Several of the key features of this unique disease are presented focusing on the importance of periprosthetic osteolysis, comprehension of the general progressive nature of periprosthetic osteolysis, understanding of the diverse radiographic evidence of this disease, and the consequences that can occur from the disease.