The Oxinium Arthrogram: A Sign of Oxidized Zirconium Implant Failure

Dramatic Failure of an OXINIUM Total Knee Arthroplasty With a Massive Pseudotumor Formation

Since the early 2000s, oxidized zirconium implants have emerged as a valuable option in total hip and knee arthroplasty due to their wear resistance and suitability for patients with metal hypersensitivity. The surface of these components is created through a heating and oxidation process of a zirconium alloy, resulting in a thin layer with favorable wear properties. However, there have been few reports of severe metallosis resulting from inadvertent wear of oxidized zirconium components through various mechanisms, including dissociation of the polyethylene liner and joint instability. We present a case involving a dramatic failure of an oxidized zirconium total knee arthroplasty, necessitating a staged revision arthroplasty.

Surface engineering of orthopedic implants for better clinical adoption

Musculoskeletal disorders are on the rise, and despite advances in alternative materials, treatment for orthopedic conditions still heavily relies on biometal-based implants and scaffolds due to their strength, durability, and biocompatibility in load-bearing applications. Bare metallic implants have been under scrutiny since their introduction, primarily due to their bioinert nature, which results in poor cell-material interaction. This challenge is further intensified by mechanical mismatches that accelerate failure, tribocorrosion-induced material degradation, and bacterial colonization, all contributing to long-term implant failure and posing a significant burden on patient populations. Recent efforts to improve orthopedic medical devices focus on surface engineering strategies that enhance the interaction between cells and materials, creating a biomimetic microenvironment and extending the service life of these implants. This review compiles various physical, chemical, and biological surface engineering approaches currently under research, providing insights into their potential and the challenges associated with their adoption from bench to bedside. Significant emphasis is placed on exploring the future of bioactive coatings, particularly the development of smart coatings like self-healing and drug-eluting coatings, the immunomodulatory effects of functional coatings and biomimetic surfaces to tackle secondary infections, representing the forefront of biomedical surface engineering. The article provides the reader with an overview of the engineering approaches to surface modification of metallic implants, covering both clinical and research perspectives and discussing limitations and future scope.

Pseudoarthrogram sign - a rare radiological appearance of implant failure in the knee

We present the radiological findings in the case of a failed unicompartmental knee arthroplasty (UKA). Although uncommon, these features are highly specific for implant failure and are an indication to consider revision. The aim of this case report is to highlight these characteristic appearances across multiple imaging modalities to both surgeons and radiologists should they encounter this in their practise.

First Italian Experience with the Oxinium Metal-Backed Fixed-Bearing Medial Journey II Unicompartmental Knee System: Promising Short-Term Outcomes of 145 Cases

(1) Background: Unicompartmental knee arthroplasty (UKA) provides a viable alternative to total knee arthroplasty (TKA) in patients with isolated medial osteoarthritis (OA). From 2007 to 2021, 23% of all primary knee arthroplasties in Italy were UKAs. We retrospectively evaluated clinical outcomes and satisfaction in patients implanted with a new oxinium metal-backed fixed-bearing medial unicompartmental prosthesis at a 24-month follow-up. (2) Methods: From December 2020 to December 2021, 145 patients were treated by a single surgeon at a single institution using the hypoallergenic Journey II prosthesis. Clinical outcome measures included the Knee Society Knee Score (KSKS), Knee Society Function Score (KSFS), Oxford Knee Society (OKS) score, University of California Los Angeles Activity Score (UCLA), the Physical Component Summary (PCS), and the Mental Component Summary (MCS), and were calculated preoperatively and at 12 and 24 months. The Forgotten Joint Score-12 (FJS-12) was calculated at 12 and 24 months. Patient satisfaction was collected at 24 months. The scores were compared using the Friedman test. (3) Results: All clinical scores improved significantly from baseline to 24 months (p < 0.0001), except for the FJS-12, which from 12 to 24 months did not improve significantly (p = 0.041). Patient satisfaction was 9.32 ± 0.74 out of 10. No patient experienced complications or required revision surgery. (4) Conclusions: The Journey II unicompartmental prosthesis is a valuable treatment option for end-stage medial OA, improving knee function, providing pain relief, and ensuring high patient satisfaction at 24 months.

Peculiar reaction of oxidized zirconium from a total knee arthroplasty prosthesis: A case report

Oxidized zirconium (OxiniumTM) prostheses, made up of a metallic alloy of zirconium with a ceramic surface formed by oxidizing the outer layer, were developed as an alternative bearing surface to reduce polyethylene wear and decrease failure of total knee arthroplasty (TKA). We report a unique catastrophic failure of an Oxinium TKA with consequent accelerated wear and severe metallosis. Intraoperatively, we observed extensive wear grooving of the femoral component with exposure of the underlying silver layers and the complete wear of polyethylene on the medial side. Metallic debris had a peculiar arthrogram appearance, noted within the cut surface of the femur and tibia, indicative of the osteolysis that occurred, leading up to the failure of the implants. The histopathologic examination revealed a collection of macrophages with foreign-body reactions and black-pigmented metal-induced wear particles. Oxinium has clear benefits regarding superior wear properties; however, surgeons need to be aware that there is a risk of exposure to the underlying layers that may precede accelerated wear, deformation, and metallosis. Uncovering the deeper layers could result in the appearance of an arthrogram on plain radiographs. Early identification of polyethylene wear and prompt revision is crucial to avoid the rapid progression of subsequent metallosis and catastrophic implant failure, specifically when using oxidized zirconium components for TKA. To the best of our knowledge, this is the first report presenting a detailed histologic analysis to provide insight into the mechanisms of the failed Oxinium components.

Oxidized Zirconium Bearing Surface Failure in Total Knee Arthroplasty: A Unique Case Report of Isolated Medial Compartment with Catastrophic Results

Introduction

Oxidized Zirconium (OXINIUM™) is a metal alloy with a ceramic surface, utilized to increase the longevity of knee and hip implantations and reduce polyethylene wear. Polyethylene-based spacers are effective in infection control and prosthetic stability. Therefore, understanding the interactions between the polyethylene spacer and metallic counterparts is essential in surgical decision-making. Furthermore, understanding how patients may present when catastrophic failure of these components arises is imperative. Herein, we present a unique case of atraumatic OXINIUM™ wear in a middle-aged female after uneventful primary total knee arthroplasty (TKA), highlighting atypical clinical features and addressing the surgical management of this unexpected implant failure.

Case Report

A 51-year-old African American female presented from an outside facility with persistent left knee pain after undergoing a TKA with a Smith and Nephew OXINIUM™ coated knee. The patient presented to the senior author's clinic with worsening symptoms 2-year postoperatively from her primary left TKA by another surgeon. After a thorough work-up which was essentially unremarkable-3 years from her initial surgery - the recommendation was made for surgical revision given clinical concern for instability. During the initial surgical approach, significant sparking of the tissue was noted on the use of electrocautery. Once the capsule was dissected, black synovial fluid with soft tissue involvement was noted. Intraoperative analysis of the polyethylene spacer revealed disintegration in the medial compartment with loss of the zirconium coating along the femoral component. There was no evidence of polyethylene spacer wear within the lateral compartment. The primary components were explanted and replaced with a nickel-free implant. Following revision, the patient reported complete resolution of her symptoms with improvement in active range of motion.

Conclusion

This case illustrates a unique presentation of atraumatic prosthetic surface coating failure after an uneventful primary TKA with well-aligned post-operative radiographs. Instability in the posterior stabilized total knee caused the polyethylene liner to come out of place, causing articulation of femoral and tibial components, creating the metal debris. Patients who present with persistent symptoms-of unknown etiology - after primary TKA should be considered for enhanced screenings and early surgical intervention.

Biocompatible Ti3Au-Ag/Cu thin film coatings with enhanced mechanical and antimicrobial functionality

BACKGROUND

Biofilm formation on medical device surfaces is a persistent problem that shelters bacteria and encourages infections and implant rejection. One promising approach to tackle this problem is to coat the medical device with an antimicrobial material. In this work, for the first time, we impart antimicrobial functionality to Ti3Au intermetallic alloy thin film coatings, while maintaining their superior mechanical hardness and biocompatibility.

METHODS

A mosaic Ti sputtering target is developed to dope controlled amounts of antimicrobial elements of Ag and Cu into a Ti3Au coating matrix by precise control of individual target power levels. The resulting Ti3Au-Ag/Cu thin film coatings are then systematically characterised for their structural, chemical, morphological, mechanical, corrosion, biocompatibility-cytotoxicity and antimicrobial properties.

RESULTS

X-ray diffraction patterns reveal the formation of a super hard β-Ti3Au phase, but the thin films undergo a transition in crystal orientation from (200) to (211) with increasing Ag concentration, whereas introduction of Cu brings no observable changes in crystal orientation. Scanning and transmission electron microscopy analysis show the polyhedral shape of the Ti3Au crystal but agglomeration of Ag particles between crystal grains begins at 1.2 at% Ag and develops into large granules with increasing Ag concentration up to 4.1 at%. The smallest doping concentration of 0.2 at% Ag raises the hardness of the thin film to 14.7 GPa, a 360% improvement compared to the ∼4 GPa hardness of the standard Ti6Al4V base alloy. On the other hand, addition of Cu brings a 315-330% improvement in mechanical hardness of films throughout the entire concentration range of 0.5-7.1 at%. The thin films also show good electrochemical corrosion resistance and a > tenfold reduction in wear rate compared to Ti6Al4V alloy. All thin film samples exhibit very safe cytotoxic profiles towards L929 mouse fibroblast cells when analysed with Alamar blue assay, with ion leaching concentrations lower than 0.2 ppm for Ag and 0.08 ppm for Cu and conductivity tests reveal the positive effect of increased conductivity on myogenic differentiation. Antimicrobial tests show a drastic reduction in microbial survival over a short test period of < 20 min for Ti3Au films doped with Ag or Cu concentrations as low as 0.2-0.5 at%.

CONCLUSION

Therefore, according to these results, this work presents a new antimicrobial Ti3Au-Ag/Cu coating material with excellent mechanical performance with the potential to develop wear resistant medical implant devices with resistance to biofilm formation and bacterial infection.

Polyethylene Luxation in an Oxinium Fixed-bearing Unicompartmental Knee Replacement Leading to Metallosis: A Case Reports for an Early and a Late Presentation

Introduction

Polyethylene (PE) subluxation is a rare complication after fixed-bearing unicompartmental knee replacement. We present two cases of PE luxation with a rapid onset of metallosis in a unicompartmental knee replacement made of Oxinium, one early presentation 3 months after surgery and the other case 6 years after.

Case Report

Case 1: A 84-year-old male underwent a fixed-bearing medial unicompartmental knee replacement in his left knee. Standard surgery was carried out with robotic assistance. Three months after surgery, he felt acute pain in the anterior portion of his knee. Radiographs showed that the PE was luxated anteriorly and a radiopaque "cloud" that blurs the vision of the implants suggesting metallosis. In the revision surgery, abundant blackish liquid and metallic-like debris were deposited in the synovial tissue and capsule around the knee. The tibial and femoral components presented extensive wear areas, suggesting extensive metal-to-metal contact. Both components were removed, and a posterior stabilized total knee prosthesis was placed. Case 2: A 50-year-old male patient underwent a fixed-bearing medial unicompartmental knee replacement. After 6 years, he complained of insidious pain in the posteromedial side of his knee. During the physical examination, significant joint effusion, a loss of extension, and a limited flexion were observed, with flexion reaching only up to 80°. The patient did not report systemic symptoms associated with metallosis, and no signs of systemic involvement were found. Radiographs show similar findings than in case 1, but the radiopaque "cloud" was limited to the knee. In the revision surgery, both components were removed. The tibial and femur components had extensive wear, especially in the posterior-central portion. A posterior stabilized total knee prosthesis was used.

Conclusion

Emphasis on careful engagement between the PE and the tibial component is a must, checking that no tissue or cement gets in the way of the anchoring system. Furthermore, prosthesis designs must look for models with a more friendly, engaging system to prevent early presentation. The radiographs assessing the height of the PE - especially in the posterior area - must be carried out. In the case of metallosis and PE luxation, we suggest performing a revision surgery with total knee arthroplasty; however, there is little evidence for a strong recommendation.

Updates on Biomaterials Used in Total Hip Arthroplasty (THA)

One of the most popular and effective orthopedic surgical interventions for treating a variety of hip diseases is total hip arthroplasty. Despite being a radical procedure that involves replacing bone and cartilaginous surfaces with biomaterials, it produces excellent outcomes that significantly increase the patient's quality of life. Patient factors and surgical technique, as well as biomaterials, play a role in prosthetic survival, with aseptic loosening (one of the most common causes of total hip arthroplasty failure) being linked to the quality of biomaterials utilized. Over the years, various biomaterials have been developed to limit the amount of wear particles generated over time by friction between the prosthetic head (metal alloys or ceramic) and the insert fixed in the acetabular component (polyethylene or ceramic). An ideal biomaterial must be biocompatible, have a low coefficient of friction, be corrosion resistant, and have great mechanical power. Comprehensive knowledge regarding what causes hip arthroplasty failure, as well as improvements in biomaterial quality and surgical technique, will influence the survivability of the prosthetic implant. The purpose of this article was to assess the benefits and drawbacks of various biomaterial and friction couples used in total hip arthroplasties by reviewing the scientific literature published over the last 10 years.

Bilateral Failure of Oxidized Zirconium Implants in Total Knee Arthroplasty

Oxidized zirconium was first introduced in total hip arthroplasty procedures to merge the strengths of metal and ceramic into one prosthetic. The subsequent adoption of oxidized zirconium (oxinium) for total knee arthroplasty is attributed to the theory of causing less wear on the tibial components compared to the alternative, cobalt chromium. However, the superficial layer of the femoral component is occasionally breached, exposing the softer zirconium substrate. Multiple mechanisms leading to zirconium substrate exposure have been explained, including collateral ligament instability and polyethylene wear. Such a failure may lead to damage to the periprosthetic tissues and often requires a revision procedure. In the current case report, we present a case of bilateral total knee arthroplasty with oxidized zirconium components that resulted in catastrophic failure and subsequent revision with hinged knee prostheses.

Fracture of the oxidized zirconium femoral component after total knee arthroplasty

BACKGROUND

Femoral component fracture is a rare complication of total knee arthroplasty (TKA).

CASE

We report a case of oxidized zirconium (Oxinium) femoral component fracture after total knee arthroplasty. The fracture site was the junction of the central and medial flanges. The patellar component and polyethylene insert had delamination at the contact point of the fracture line, and the tibial tray had loosening at the medial side. There was no cement adherence at the component fracture site, suggesting that debonding had occurred at the cement-implant interface in this area. Examination with a scanning electron microscope revealed beach marks, which are characteristic findings of metal fatigue.

CONCLUSION

We considered that the cause of femoral component fracture was a fatigue fracture due to poor fixation of the component to the bone caused by poor osteotomy technique or poor cementing technique. To our knowledge, this is the first case of Oxinium femoral component fracture.

3D Bioprinted Implants for Cartilage Repair in Intervertebral Discs and Knee Menisci

Cartilage defects pose a significant clinical challenge as they can lead to joint pain, swelling and stiffness, which reduces mobility and function thereby significantly affecting the quality of life of patients. More than 250,000 cartilage repair surgeries are performed in the United States every year. The current gold standard is the treatment of focal cartilage defects and bone damage with nonflexible metal or plastic prosthetics. However, these prosthetics are often made from hard and stiff materials that limits mobility and flexibility, and results in leaching of metal particles into the body, degeneration of adjacent soft bone tissues and possible failure of the implant with time. As a result, the patients may require revision surgeries to replace the worn implants or adjacent vertebrae. More recently, autograft - and allograft-based repair strategies have been studied, however these too are limited by donor site morbidity and the limited availability of tissues for surgery. There has been increasing interest in the past two decades in the area of cartilage tissue engineering where methods like 3D bioprinting may be implemented to generate functional constructs using a combination of cells, growth factors (GF) and biocompatible materials. 3D bioprinting allows for the modulation of mechanical properties of the developed constructs to maintain the required flexibility following implantation while also providing the stiffness needed to support body weight. In this review, we will provide a comprehensive overview of current advances in 3D bioprinting for cartilage tissue engineering for knee menisci and intervertebral disc repair. We will also discuss promising medical-grade materials and techniques that can be used for printing, and the future outlook of this emerging field.