Clinical and radiological outcomes of trabecular metal systems and antiprotrusion cages in acetabular revision surgery with severe defects: a comparative study

Outcomes of Lateral Transfibular Approach for Total Ankle Replacement

Total ankle replacement through a lateral transfibular approach with trabecular metal implants was introduced in 2012 and originally was advertised as a safer approach in terms of wound healing issues. Further studies showed no significant difference comparing anterior and lateral approach for infections and would healing issues, whereas the main advantage is deformity correction, acting on coronal, sagittal, and rotational deformities and on fibular length issues. It showed a survival rate of 97.7% at 5 years follow-up.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

IV.

The modern Burch-Schneider antiprotrusio cage for the treatment of acetabular defects: is it still an option? A systematic review

BACKGROUND

A number of papers have been published about the clinical performance of modern rough-blasted titanium Burch-Schneider antiprotrusio cages (BS-APCs) for the treatment of acetabular bone defects. However, no systematic review of the literature has been published to date.

METHODS

The US National Library of Medicine (PubMed/MEDLINE), EMBASE, and the Cochrane Database of Systematic Reviews were queried for publications using keywords pertinent to Burch-Schneider antiprotrusio cage, revision THA, and clinical outcomes.

RESULTS

8 articles were found to be suitable for inclusion in the present study in which 374 cases (370 patients) had been treated with modern BS-APCs. Most acetabular bone defects were type 3 according to the Paprosky classification (type 2C: 18.1%, 3A: 51%, and 3B: 28.9%). The overall re-revision rate for the 374 acetabular reconstructions with modern BS-APCs was 11.5% (43 cases). The short-term survival rate of the modern BS-APC construct was 90.6% (339 out of 374 cases), while the mid-term survival rate was 85.6% (320 out of 374 cases), and the long-term survival rate 62% (54 out of 87 cases). The most common reasons for revision were aseptic loosening (5.6%), periprosthetic joint infection (3.8%), dislocation (2.7%), and acetabular periprosthetic fracture (1.9%).

CONCLUSIONS

There was moderate quality evidence to show that the use of modern rough blasted titanium BS-APCs in cases of acetabular bone loss has an unacceptably high failure rate (38%). Given that antiprotrusio cages do not provide any biological fixation, we would not recommend the routine use of modern BS-APCs in complex revision THA cases. By contrast, the satisfactory short- to mid-term outcome of modern BS-APCs in combination with their low cost compared to highly porous acetabular implants, make us feel that BS-APCs might still be used in selected elderly or low-demand patients without severe superomedial acetabular bone loss.

Long-term functional results of revision hip replacement using Burch-Schneider cages

Introduction

One of the most common and effective treatments for end-stage hip osteoarthritis is total hip arthroplasty (THA). According to the WHO, 1.5 million, more than 500,000, and approximately 100,000 THAs are performed annually in the world, in the USA, and in Russia, respectively. The use of Burch-Schneider cages has progressively increased since their introduction in 1975, with more than 125,000 cages being implanted by 2006. This design for revision surgery remains valid today.The objectives were to conduct a retrospective analysis of anti-protrusion cages in revision THA and evaluate long-term functional results.

Methods

Fifty-eight revision surgeries were performed at Botkin Hospital from 2003 to 2020 with anti-protrusion Burch-Schneider cages because of aseptic loosening of the acetabular component. The average age of the examined patients was 61.2 (±12.9) years. The maximum follow-up duration was 17 years. The average follow-up duration was 10.5 (±4.1) years. We used the functional Harris, WOMAC, SF-36, and FJS-12 scales to evaluate functional results. The patients were distributed into the following groups according to the Paprosky classification: 2C, 3A, and 3B.

Results

Group 2C showed good functional results, with a Harris score of 87 (±6.9), an FJS-12 score of 63.2 (±4.8), a WOMAC score of 175 (±16.7), and an Oxford Hip score of 39.06 (±9.1). Group 3A also showed good functional scores, with a Harris score of 78 (±7.1), an FJS-12 score of 61.2 (±5.1), a WOMAC score of 168 (±17.1), and an Oxford Hip score of 42.12 (±8.7). Group 3B showed satisfactory functional results, with a Harris score of 70 (±5.9), an FJS-12 score of 58.9 (±4.4), a WOMAC score of 166 (±18.1), and an Oxford Hip score of 48.4 (±9.4).Among patients who underwent revision surgery using Burch-Schneider rings, 16 needed to undergo repeat revision surgery. Periprosthetic infection occurred in 5 patients, aseptic loosening in 7, and periprosthetic fracture in 3.

Conclusions

The anti-protrusion Burch-Schneider system is a necessary and up-to-date element of THA and can be used with great efficacy in revision THA. Despite the rapid development of technologies and the appearance of new, highly efficient devices, there is still room for systems such as Burch-Schneider rings. However, there are relatively few indications for their use, with the main indications for the use of anti-protrusion systems being conditions related to bone defects of the acetabular roof and bone mass loss of the acetabular floor.

Improvement of surgical time and functional results after do-it-yourself 3D-printed model preoperative planning in acetabular defects Paprosky IIA-IIIB

INTRODUCTION

The correct positioning of the implant in revision total hip arthroplasty (rTHA) is critical to obtaining substantial functional outcomes, and to avoiding complications. Current literature supports three-dimensional (3D)-printed models as potentially useful tools for preplanning, as well as the "do it yourself (DIY)" methodology to reduce both the time and costs of this procedure. However, no study has determined the efficacy of both methods combined in a cohort of patients with severe acetabular defects. In the lack of bibliography, we performed rTHA after preoperative planning by DIY-3D-printed models to evaluate its influence in: 1) the surgical time, 2) the functional scores, 3) the intra and postoperative complications, and 4) the reconstruction of the center of rotation (COR) of the hip.

HYPOTHESIS

Preoperative planning through 3D-DIY printed models will both improve the accuracy of the implant positioning, and the surgical time, leading the latter to improved functional scores and reduced complications.

MATERIALS & METHODS

A comparative study of 21 patients with Paprosky IIB to IIIB acetabular defects who underwent rTHA after 3D-printed model preoperative planning by the DIY method between 2016 and 2019 was conducted. A historical cohort of 24 patients served as the comparator. Surgical time, reconstruction of the COR, functional scores, and complications were analyzed.

RESULTS

The mean follow-up was 32.4 (range, 12 to 60) months. All the patients showed significant improvement of the Harris hip score (HHS) after the operation (3D group: 26.58±10.73; control group 22.47±15.43 (p=0.00)). In the 3D-printed model preoperative planning group the mean operation time and the intraoperative complications were significantly lower (156.15±43.03min vs 187.5±54.38min (p=0.045); and 19% vs 62.5% (p=0.003), respectively), and the HHS and patient satisfaction score (PSS) were significantly greater (83.74±8.49 vs 75.59±11.46 (p=0.019); and 8.17±0.88 vs 7.36±1.17 (p=0.023), respectively). No differences were found in the postoperative complications, nor in the restoration of the COR as determined from the acetabular index, verticalization or horizontalization, although the acetabular index was closer to the intended one in the 3D-printed model planning group (46.67°±7.63 vs 49.22±8.1 (p=0.284)).

CONCLUSION

Preoperative planning of severe acetabular defects through 3D-printed models shortens the surgical time, leading to a decrease in complications and thus to better functional outcomes and greater patient satisfaction. Moreover, the DIY philosophy could decrease both the time and costs of traditional 3D planning.

LEVEL OF EVIDENCE

III, retrospective case matched study.

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.

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

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

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

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

Porous Tantalum and Titanium in Orthopedics: A Review

Porous metal is metal with special porous structures, which can offer high biocompatibility and low Young's modulus to satisfy the need for orthopedic applications. Titanium and tantalum are the most widely used porous metals in orthopedics due to their excellent biomechanical properties and biocompatibility. Porous titanium and tantalum have been studied and applied for a long history until now. Here in this review, various manufacturing methods of titanium and tantalum porous metals are introduced. Application of these porous metals in different parts of the body are summarized, and strengths and weaknesses of these porous metal implants in clinical practice are discussed frankly for future improvement from the viewpoint of orthopedic surgeons. Then according to the requirements from clinics, progress in research for clinical use is illustrated in four aspects. Various creative designs of microporous and functionally gradient structure, surface modification, and functional compound systems of porous metal are exhibited as reference for future research. Finally, the directions of orthopedic porous metal development were proposed from the clinical view based on the rapid progress of additive manufacturing. Controllable design of both macroscopic anatomical bionic shape and microscopic functional bionic gradient porous metal, which could meet the rigorous mechanical demand of bone reconstruction, should be developed as the focus. The modification of a porous metal surface and construction of a functional porous metal compound system, empowering stronger cell proliferation and antimicrobial and antineoplastic property to the porous metal implant, also should be taken into consideration.

Highly porous titanium cup in cementless total hip arthroplasty: registry results at eight years

PURPOSE

Highly porous cups were developed to improve osseointegration and reduce the rate of aseptic loosening. Highly porous titanium cups could mix the reliability of titanium metal with an enhanced porosity, improving the bony ingrowth. The aim of this report was to assess the survival rates and reasons for revision of a highly porous titanium cup, Fixa Ti-Por (Adler Ortho, Milan, Italy), fabricated using an additive manufacturing.

METHODS

The Registry of Prosthetic Orthopedic Implants (RIPO), the Emilia-Romagna region arthroplasty registry, was enquired about cementless cups, implanted since July 2007. Ti-Por cups were compared to all the other cementless sockets, acting as a control group. The survival rates and reasons for revision were evaluated and compared. Comparisons with the same articular couplings were also provided.

RESULTS

When all the articular couplings were included, Ti-Por performed better, achieving a statistically higher survival rate than the control group (98.7% vs 97.9%) and a statistically lower incidence of cup aseptic loosening. In case of ceramic on polyethylene couplings, Ti-Por achieved similar survival rate: cup aseptic loosening in Ti-Por group was 0.2%, whereas the control group rated 0.4%. In ceramic-on-ceramic implants, the survival rate was similar in the two groups, Ti-Por achieving a cup aseptic loosening rate of 0.1% (vs 0.14% in the control group).

CONCLUSION

Highly porous titanium cups showed trustworthy results at eight years, reducing the rate of aseptic loosening. Longer follow-ups, ion analyses, and pre-clinical in vivo studies would be helpful to better define the reliability of these devices and their advantages.

A single centre study of 41 cases on the use of porous tantalum metal implants in acetabular revision surgery

Background

This study aims at investigating cup survival of porous tantalum revision cups and identifies risk factors for failure.

Methods

We retrospectively reviewed 41 patients treated between 2010 and 2012. Main indications were aseptic loosening in 83% and two-stage exchange after periprosthetic joint infection in 17% of cases. Mean follow-up period was 72 months. Femoral megaprostheses were used in 13% of cases. Most defects were classified as Paprosky 3b (29%). Function was assessed using the Harris Hip score.

Results

Aseptic cup survivorship was 80% at 104 months (95% Confidence Interval 67.4–92.4). Overall implant survival was 73%. Major bone loss defects (Paprosky types 2c to 3b) were associated with a significantly higher rate of failure than minor defects (P = 0.002). There were eight cases of aseptic loosening (19.5%) and two of infection (4.9%). Previous surgeries, indication for acetabular revision, patient-related risk factors and use of megaprostheses did not significantly influence implant survival. The Harris Hip Score improved from a median of 40 (Interquartile range 31–45) to 82 (interquartile range 65–88) postoperative (P < 0.0001).

Conclusions

In summary, the use of porous tantalum metal implants in acetabular revision surgery achieves good to excellent short- term and mid-term functional results and an acceptable complication rate relative to the extent of defect and previous surgery. However, one should be aware of potential limitations of the implants in addressing large defects and discontinuity.

Acetabular reinforcement rings associated with allograft for severe acetabular defects

Acetabular revisions with severe bone defects can be challenging procedures. Several grading systems have been set into place to help the surgeon adequately gauge the degree of bone loss within the acetabulum. Internationally innovative research in orthopedics and bio-engineering has helped with progression of successful techniques and rings to re-establish the normal anatomy of the hip. The purpose of this review is to evaluate the outcomes of the different acetabular reinforcement rings in the setting of severe acetabular defects. A successive report of relevant data from the literature of multiple techniques will be provided. The procedures include the cup-cage, the Müller ring, the Ganz Ring, the Kerboull acetabular reinforcement device (KARD), the graft augmentation prosthesis (GAP) ring, and the Burch-Schneider ring. The main focus of this overview is rings only; other devices such as trabecular augments, custom-made cages, or oblong cups are not discussed. Furthermore, a special emphasis on the surgical technique of the KARD is also given. Procedures using these rings are usually associated with bone grafts either bulk or morselized. When considering the available data on these various rings used for reconstruction of the severely damaged acetabulum, the cup-cage, the KARD, and the Burch-Schneider ring appear to be reliable options for more successful long-term outcomes.