Tritanium Acetabular Cup in Revision Hip Replacement: A Six to Ten Years of Follow-Up Study

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

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

Outcomes of novel 3D-printed fully porous titanium cup and a cemented highly cross-linked polyethylene liner in complex and revision total hip arthroplasty

INTRODUCTION

A novel fully porous acetabular titanium shell has been designed to reduce stiffness mismatch between bone and implant and promote osseointegration in complex (cTHA) and revision total hip arthroplasty (rTHA). A highly cross-linked polyethylene (XLPE) liner is cemented within the cup to reduce wear rates and increase survivorship. This study reported the outcomes of an XLPE liner cemented into a novel 3D-printed fully porous cup in cTHA and rTHA.

METHODS

Presented was a multicenter retrospective review of 40 patients (6 cTHA and 34 rTHA) who underwent THA with a fully porous titanium acetabular cup and cemented XLPE liner. Data were collected on demographics, surgical information, outcomes, including osseointegration and migration and implant survivorship.

RESULTS

On average, patients were 71.42 ± 9.97 years old and obese (BMI: 30.36 ± 6.88 kg/m²) and were followed up for a mean time of 2.21 ± 0.77 years. Six patients underwent cTHA and 34 patients underwent rTHA. The mean hospital length of stay was 5.34 ± 3.34 days. Three (7.5%) 90-day readmissions were noted. Harris Hip Scores improved, on average, from 53.87 ± 12.58 preoperatively to 83.53 ± 12.15 postoperatively (P<0.001). One case of acetabular shell aspetic loosening with migration was noted. Thirty-nine of the 40 acetabular components were fully osseointegrated without migration. Two patients underwent re-revision surgery for PJI and one patient received acetabular shell+liner re-revision due to aseptic loosening. Kaplan-Meier analysis showed an all-cause revision-free survival rate of 95.0% at 6 months and 1 year, and 92.0% at 4-years. Aseptic acetabular cup, liner dislocation/loosening, and fracture-free survival was 100% at 6 months and 1-year, and 97.1% at 2 years.

CONCLUSION

The combined use of a novel 3D-printed fully porous titanium acetabular shell and cemented XLPE acetabular liner yielded excellent rates of osseointegration, and all-cause and acetabular aseptic loosening survivorship at a minimum 1-year follow-up. Further long-term studies are needed to assess the longevity of this construct.

Extended Fixation for Paprosky Type III Acetabular Defects in Revision Total Hip Arthroplasty with a Minimum Follow-Up of 2 Years

OBJECTIVE

Revision of total hip arthroplasty for patients with severe acetabular bone defects is challenging. This study aims to report the minimum 2 years outcome of the iliac extended fixation technique in patients with Paprosky type III acetabular defects.

METHODS

Fifty-seven revision total hip arthroplasty patients were retrospectively reviewed who underwent reconstruction with the concept of iliac extended fixation from 2014 to 2017 in our hospital. We proposed a new concept of "iliac extended fixation" in revision total hip arthroplasty as fixation extending superiorly 2 cm beyond the original acetabular rim with porous metal augments, which was further classified into intracavitary and extracavitary fixation. Patients were assessed using the Harris Hip Score and the Western Ontario and McMaster Universities Osteoarthritis Index Score. Radiographs and patient-reported satisfaction were assessed.

RESULTS

At an average follow-up of 63 months (range 25-88 months), the postoperative Harris Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index scores were significantly improved at the last follow-up (p < 0.001). The center of rotation was significantly improved (p < 0.05). Fifty-three (93.0%) patients were satisfied with the outcome. The extracavitary iliac extended fixation group had higher rate of osteointegration in zone 1A (the superior lateral zone) than the intracavitary iliac extended fixation group (82.3% vs 55.0%, p = 0.015), and significantly more horizontal screws fixation (5.1 ± 24.7° vs 42.3 ± 36.8°, p < 0.001).

CONCLUSION

Intracavitary and extracavitary iliac extended fixation with porous metal augments and cementless cups are effective in reconstructing severe superior acetabular bone defects. The difference in screw direction might reflect the different biomechanics of augment fixation.

Minimum 2-Year Outcomes of a Novel 3D-printed Fully Porous Titanium Acetabular Shell in Revision Total Hip Arthroplasty

Background

Fully porous acetabular shells are an appealing choice for patients with extensive acetabular defects undergoing revision total hip arthroplasty (rTHA). This study reports on the early outcomes of a novel 3-D printed fully porous titanium acetabular shell in revision acetabular reconstruction.

Methods

A multicenter retrospective study of patients who received a fully porous titanium acetabular shell for rTHA with a minimum of 2 years of follow-up was conducted. The primary outcome was rate of acetabular revision.

Results

The final study cohort comprised 68 patients with a mean age of 67.6 years (standard deviation 10.4) and body mass index of 29.5 kg/m² (standard deviation 5.9). Ninety-four percent had a preoperative Paprosky defect grade of 2A or higher. The average follow-up duration was 3.0 years (range 2.0-5.1). Revision-free survivorship at 2 years was 81% for all causes, 88% for acetabular revisions, and 90% for acetabular revision for aseptic acetabular shell failure. Eight shells were explanted within 2 years (12%): 3 for failure of osseointegration/aseptic loosening (4%) after 15, 17, and 20 months; 3 for infection (4%) after 1, 3, and 6 months; and 2 for instability (3%). At the latest postoperative follow-up, all unrevised shells showed radiographic signs of osseointegration, and none had migrated.

Conclusions

This novel 3-D printed fully porous titanium shell in rTHA demonstrated good survivorship and osseointegration when used in complex acetabular reconstruction at a minimum of 2 years.

Level of evidence

IV, case series.

In vivo evaluation of osseointegration ability of sintered bionic trabecular porous titanium alloy as artificial hip prosthesis

Hydroxyapatite (HA) coatings have been widely used for improving the bone-implant interface (BII) bonding of the artificial joint prostheses. However, the incidence of prosthetic revisions due to aseptic loosening remains high. Porous materials, including three-dimensional (3D) printing, can reduce the elastic modulus and improve osseointegration at the BII. In our previous study, we identified a porous material with a sintered bionic trabecular structure with in vitro and in vivo bio-safety as well as in vivo mechanical safety. This study aimed to compare the difference in osseointegration ability of the different porous materials and HA-coated titanium alloy in the BII. We fabricated sintered bionic trabecular porous titanium acetabular cups, 3D-printed porous titanium acetabular cups, and HA-coated titanium alloy acetabular cups for producing a hip prosthesis suitable for beagle dogs. Subsequently, the imaging and histomorphological analysis of the three materials under mechanical loading in animals was performed (at months 1, 3, and 6). The results suggested that both sintered bionic porous titanium alloy and 3D-printed titanium alloy exhibited superior performances in promoting osseointegration at the BII than the HA-coated titanium alloy. In particular, the sintered bionic porous titanium alloy exhibited a favorable bone ingrowth performance at an early stage (month 1). A comparison of the two porous titanium alloys suggested that the sintered bionic porous titanium alloys exhibit superior bone in growth properties and osseointegration ability. Overall, our findings provide an experimental basis for the clinical application of sintered bionic trabecular porous titanium alloys.

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

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

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Excellent mid-term outcomes with a hemispheric titanium porous-coated acetabular component for total hip arthroplasty: 7-10 year follow-up

INTRODUCTION

Third-generation hemispheric, titanium porous-coated (HTPC) acetabular cups have been shown to achieve good biologic fixation through enhanced porous ingrowth surfaces. They also allow for a wide range of bearing options, including polyethylene, dual-mobility, and ceramic liners. The purpose of the study is to review the mid-term clinical outcomes an HTPC acetabular cup with a minimum of 7-year follow-up.

METHODS

A retrospective, observational study was conducted on all consecutive patients who underwent total hip arthroplasty (THA) with an HTCP acetabular cup at an urban, tertiary referral centre. Descriptive statistics were used describe baseline patient characteristics. Outcomes collected included postoperative complications, survival free of reoperations, and presence of osteolysis at latest imaging follow-up. Implant survival was analysed using the Kaplan-Meier method.

RESULTS

118 cases (114 primary, 4 revision) underwent THA with the HTCP acetabular cup at an average follow-up of 8.16 ± 0.85 years (range 7.02-10.28 years). Mean patient age at the time of surgery was 61.29 ± 12.04 years. All cases utilised a high-molecular-weight polyethylene (HMWPE) liner. None of the acetabular cups showed loosening or migration at the latest follow-up. There were 2 revisions in our study, 1 for abductor mechanism disruption and 1 due to surgical site infection where the acetabular cup was revised. Kaplan-Meier survivorship analysis for all-cause revision at 7 and 10-year follow-up showed a survival rate of 99.1% (95% confidence interval, 94.1-99.9%). Survivorship analysis for aseptic acetabular revision at 10-year follow-up showed a survival rate of 100%.

CONCLUSIONS

At long-term follow-up, no radiologic and minimal clinical complications were identified in this series. The HTPC acetabular cup system, used in conjunction with a HMWPE liner, demonstrates excellent outcomes and survivorship when compared to earlier mid-term studies published in the literature.

Is there a problem with modular dual mobility acetabular components in revision total hip arthroplasty at mid-term follow-up?

AIMS

Modular dual mobility (MDM) acetabular components are often used with the aim of reducing the risk of dislocation in revision total hip arthroplasty (THA). There is, however, little information in the literature about its use in this context. The aim of this study, therefore, was to evaluate the outcomes in a cohort of patients in whom MDM components were used at revision THA, with a mean follow-up of more than five years.

METHODS

Using the database of a single academic centre, 126 revision THAs in 117 patients using a single design of an MDM acetabular component were retrospectively reviewed. A total of 94 revision THAs in 88 patients with a mean follow-up of 5.5 years were included in the study. Survivorship was analyzed with the endpoints of dislocation, reoperation for dislocation, acetabular revision for aseptic loosening, and acetabular revision for any reason. The secondary endpoints were surgical complications and the radiological outcome.

RESULTS

The overall rate of dislocation was 11%, with a six-year survival of 91%. Reoperation for dislocation was performed in seven patients (7%), with a six-year survival of 94%. The dislocations were early (at a mean of 33 days) in six patients, and late (at a mean of 4.3 years) in four patients. There were three intraprosthetic dissociations. An outer head diameter of ≥ 48 mm was associated with a lower risk of dislocation (p = 0.013). Lumbrosacral fusion was associated with increased dislocation (p = 0.004). Four revision THAs (4%) were further revised for aseptic acetabular loosening, and severe bone loss (Paprosky III) at the time of the initial revision was significantly associated with further revision for aseptic acetabular loosening (p = 0.008). Fourteen acetabular components (15%) were re-revised for infection, and a pre-revision diagnosis of reimplantation after periprosthetic joint infection (PJI) was associated with subsequent PJI (p < 0.001). Two THAs had visible metallic changes on the backside of the cobalt chromium liner.

CONCLUSION

When using this MDM component in revision THA, at a mean follow-up of 5.5 years, there was a higher rate of dislocation (11%) than previously reported. The size of the outer bearing was related to the risk of dislocation. There was a low rate of aseptic acetabular loosening. Longer follow-up of this MDM component and evaluation of other designs are warranted. Cite this article: Bone Joint J 2021;103-B(7 Supple B):66-72.

Highly Porous Titanium Acetabular Components in Primary and Revision Total Hip Arthroplasty: A Systematic Review

BACKGROUND

A number of papers have been published reporting on the clinical performance of highly porous coated titanium acetabular cups in primary and revision total hip arthroplasty (THA). 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 utilizing the following keywords: "tritanium" OR "highly-porous" AND "titanium" OR "acetabular" AND "trabecular" AND "titanium".

RESULTS

Overall, 16 studies were included in this review (11,366 cases; 60% females, 2-7 years mean follow-up). The overall survival rate of highly porous titanium acetabular components in primary cases was 99.3% (10,811 of 10,886 cases), whereas the rate of aseptic loosening was 0.1%. The overall survival rate of the highly porous titanium acetabular components in revision THA cases was 93.5% (449 of 480 cases), whereas the rate of aseptic loosening was 2.1%.

CONCLUSION

There was moderate quality evidence to show that the use of highly porous titanium acetabular components in primary and revision THA cases is associated with satisfactory clinical outcomes in the short- and medium-term, without showing any evidence of cup migration or radiolucency. Taking into consideration that there is no evidence yet regarding the long-term survivorship of these components, we feel that further research of higher quality is required to generate more evidence-based conclusions regarding the longevity of highly porous titanium acetabular implants compared with conventional titanium counterparts.

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

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