Postmortem Retrieval Analysis of Metallosis and Periprosthetic Tissue Metal Concentrations in Total Knee Arthroplasty

Retrieval analysis in total knee arthroplasty

Retrieval analysis in total knee arthroplasty (TKA) has been little studied in the literature. A narrative review of the literature to understand the current importance of retrieval analysis in TKA has been conducted. On August 27, 2024, a literature search was performed in PubMed using "TKA retrieval analysis" as keywords. A total of 160 articles were found, of which only 19 were analyzed because they were directly related to the subject of this article. Rotating-platform (mobile-bearing) TKA has no surface damage advantage over fixed-bearing TKA. TKAs with central locking mechanisms are more prone to debond from the cement mantle. No major wear of the polyethylene (PE) component in TKA using oxidized zirconium components occurs. Femoral components of cobalt-chromium roughen more than oxidized zirconium femoral components. The use of a polished tibial tray over an unpolished design is advised. At short-run assessment (15 months on average), antioxidant-stabilized highly crosslinked PE components are not clinically different in surface damage, density of crosslinking, or oxidation compared to standard remelted highly crosslinked PE components. A correlation between implant position and PE component surface damage has been reported. It shows the importance of optimizing component position to reduce PE component damage. Contemporary knee tumor megaendoprostheses show notable volumetric metal wear originated at the rotating hinge. Retrieval analysis in TKA renders relevant data on how different prosthetic designs described in the literature perform. Such information can help to improve future prosthetic designs to increase prosthetic survival.

Metal Release in Total Knee Arthroplasty: A Review of Mechanisms, Adverse Local Tissue Reactions, and Biological Effects

Compared to the hip, where investigators associate metal release with adverse local tissue reactions (ALTRs), metal-related complications in total knee arthroplasty (TKA) remain controversial and underexplored. Primary TKA systems use monobloc components, limiting corrosion and subsequent concerns. However, like the joints they replace, metal components degrade in vivo. In this narrative review, we aimed to summarize clinically relevant knowledge on metal release within the context of TKA for practicing orthopaedic surgeons. We asked: do ALTRs associated with metal release occur in the knee, and if so, to what extent? To answer this research question, we identified in vivo degradation mechanisms, including wear, mechanically assisted crevice corrosion, and electrocautery damage. Next, we synthesized case reports and retrospective clinical studies documenting ALTRs in primary and revision TKAs. Then, we reviewed the biological response to cobalt chrome debris, focusing on genotoxicity, immune responses, and hypersensitivity. While clinical evidence suggests that patients rarely experience severe biological reactions like pseudotumors, ALTRs associated with metal release can and do occur following TKA. To overcome knowledge gaps related to the prevalence of ALTR in TKA, prospective clinical trials are needed.

Retrieval Analysis of Titanium Nitride Coatings for Orthopaedic Implants

BACKGROUND

The first generation of titanium nitride (TiN) coatings for orthopaedic implants was clinically introduced in the 1990s because of their promising biocompatibility, wear resistance, and corrosion resistance. This study evaluated the in vivo performance of early TiN-coated knee and hip implants, focusing on the bearing surfaces and mechanisms of in vivo damage.

METHODS

There were 13 TiN-coated implants (5 knee and 8 hip) retrieved from 8 patients as part of a multi-institutional implant retrieval program. The average implantation time was 4.25 years for knees and 17.5 years for hips. Implant revisions occurred for various reasons, including polyethylene wear, loosening, pain, infection, and instability. Components were examined using a semiquantitative scoring method, and surface roughness measurements were performed using white-light interferometry. Surface morphology, chemistry, and particle characterization were also assessed by scanning electron microscopy.

RESULTS

For hips, mild corrosion was found on femoral head tapers, along with severe scratching on certain femoral heads. Knee implants exhibited low burnishing and scratching for both mechanisms. Roughness measurements (Sa) were 37.3 nm (interquartile range = 22.0 to 62.4) for hips and 85.3 nm (interquartile range = 66.3 to 110) for knees. The observed scratch depth in both hip and knee implants due to third-body particles ranged from 0.3 to 1.3 μm. The coating coverage remained intact in the majority of the implants, with 2 cases of small, localized cohesive chipping and substrate exposure.

CONCLUSIONS

The results of this study confirm the potential in vivo durability of early TiN coatings and will be useful in benchmarking wear tests for modern TiN-coated orthopaedic implants.

Isolation and characterisation of wear debris surrounding failed total ankle replacements

Aseptic loosening and osteolysis continue to be a short- to mid-term problem for total ankle replacement (TAR) devices. The production of wear particles may contribute to poor performance, but their characteristics are not well understood. This study aimed to determine the chemical composition, size and morphology of wear particles surrounding failed TARs. A recently developed wear particle isolation method capable of isolating both high- and low-density materials was applied to 20 retrieved periprosthetic tissue samples from 15 failed TARs of three different brands. Isolated particles were imaged using ultra-high-resolution imaging and characterised manually to determine their chemical composition, size, and morphology. Six different materials were identified, which included: UHMWPE, calcium phosphate (CaP), cobalt chromium alloy (CoCr), commercially pure titanium, titanium alloy and stainless steel. Eighteen of the 20 samples contained three or more different wear particle material types. In addition to sub-micron UHMWPE particles, which were present in all samples, elongated micron-sized shards of CaP and flakes of CoCr were commonly isolated from tissues surrounding AES TARs. The mixed particles identified in this study demonstrate the existence of a complex periprosthetic environment surrounding TAR devices. The presence of such particles suggests that early failure of devices may be due in part to the multifaceted biological cascade that ensues after particle release. This study could be used to support the validation of clinically-relevant wear simulator testing, pre-clinical assessment of fixation wear and biological response studies to improve the performance of next generation ankle replacement devices. STATEMENT OF SIGNIFICANCE: Total ankle replacement devices do not perform as well as total hip and knee replacements, which is in part due to the relatively poor scientific understanding of how they fail. The excessive production of certain types of wear debris is known to contribute to joint replacement failure. This is the first study to successfully isolate and characterise high- and low-density wear particles from tissues collected from patients with a failed total ankle replacement. This article includes the chemical composition and characteristics of the wear debris generated by ankle devices, all of which may affect their performance. This research provides clinically relevant reference values and images to support the development of pre-clinical testing for future total ankle replacement designs.

Cross-sectional association between systemic metal concentrations and immune markers in patients with total joint arthroplasty

Total joint arthroplasty (TJA) implants are composed of metal components. Although they are regarded safe, the long-term immunological effects of chronic exposure to the specific implant materials are unknown. We recruited 115 hip and/or knee TJA patients (mean age 68 years) who provided a blood draw for measurement of chromium, cobalt, titanium concentrations, inflammatory markers and systemic distribution of immune cells. We examined differences between the immune markers and the systemic concentrations of chromium, cobalt and titanium. CD66-b neutrophils, early natural killer cells (NK), and eosinophils were present in higher percentages in patients with chromium and cobalt concentrations greater than the median. The opposite pattern was observed with titanium where the percentages of CD66-b neutrophils, early NK, and eosinophils were higher in patients with undetectable titanium. Cobalt concentrations were positively correlated with a higher percentage of gamma delta T cells. Both chromium and cobalt concentrations were positively correlated with higher percentages of plasmablasts. Titanium concentrations were positively correlated with higher CD4 effector memory T cells, regulatory T cell count and Th1 CD4 helper cells. In this exploratory study, we observed altered distribution of immune cells in TJA patients with elevated systemic metal concentrations. Although these correlations were not strong, these exploratory findings warrant further investigation into the role of increased metals circulating in blood and its role in immune modulation.

Neurological emergency from rare spinal metalloma: Case report and literature review

Metallosis is a rare and poorly understood long-term complication of instrumented surgery that can result in an inflammatory pseudotumor termed metalloma. We describe a particularly unique case and compare it to 6 analogous cases identified by PubMed and/or Medline search through July 2020. A 79-year-old male with multiple prior spinal lumbar fusion procedures presented with progressive weakness and pain. Imaging revealed a large mass surrounding the right-sided paraspinal rod with extension into the spinal canal, neural foramina, extraforaminal spaces, psoas muscle, marrow spaces, and right sided pedicles. The case presented is a unique example of a unilateral metalloma with mixed-metal instrumentation that created a progressive neurologic deficit without infection, pseudoarthrosis, or hardware failure. This case highlights the lack of understanding regarding the pathophysiology of metallosis and metalloma in spinal instrumentation. We highlight the imaging findings of metalloma to encourage early identification for removal and decompression.

A Unique Case of Extra-articular Extravasation of Metal Into the Lower Leg Resulting From Oxidized Zirconium Wear Particles From Total Knee Arthroplasty

With an increasing number of joint replacements and the evolution of orthopaedic implants and hardware, there is increased occurrence and awareness of metal-related sensitivity. This has resulted in the development of devices using a variety of different materials to coat the implant. One popular option is to cover the metallic surface with a ceramic. One commercially available ceramic-coated prosthesis is coated with oxidized zirconium, with the trade name Oxinium. Although pseudotumor and metallosis resulting from ceramic joint arthroplasty implants have been documented, there is limited information on the occurrence of metallosis resulting from ceramic-coated knee implants. The purpose of this case report is to discuss a potential differential diagnosis for lower leg mass after total knee arthroplasty and to present a novel case of catastrophic failure of an Oxinium-coated total knee prosthesis (Smith and Nephew) that resulted in metallosis with extra-articular extravasation along the extensor digitorum longus tendon.

New materials for hip and knee joint replacement: What's hip and what's in kneed?

Over the last three decades there have been significant advancements in the knee and hip replacement technology that has been driven by an issue in the past concerning adverse local tissue reactions, aseptic and septic loosening. The implants and the materials we utilize have improved over the last two decades and in knee and hip replacement there has been a decrease in the failures attributed to wear and osteolysis. Despite these advancements there are still issues with patient satisfaction and early revisions due to septic and aseptic loosening in knee replacement patients. This article reviews the state of current implant material technology in hip and knee replacement surgery, discusses some of the unmet needs we have in biomaterials, and reviews some of the current biomaterials and technology that may be able to solve the most common issues in the knee and hip replacement surgery.

In vitro effects of macrophages on orthopaedic implant alloys and local release of metallic alloy components

AIMS

This study aimed to determine if macrophages can attach and directly affect the oxide layers of 316L stainless steel, titanium alloy (Ti6Al4V), and cobalt-chromium-molybdenum alloy (CoCrMo) by releasing components of these alloys.

METHODS

Murine peritoneal macrophages were cultured and placed on stainless steel, CoCrMo, and Ti6Al4V discs into a 96-well plate. Cells were activated with interferon gamma and lipopolysaccharide. Macrophages on stainless steel discs produced significantly more nitric oxide (NO) compared to their control counterparts after eight to ten days and remained elevated for the duration of the experiment.

RESULTS

On stainless steel, both nonactivated and activated cell groups were shown to have a significant increase in metal ion release for Cr, Fe, and Ni (p < 0.001, p = 0.002, and p = 0.020 respectively) compared with medium only and showed macrophage-sized corrosive pits on the stainless steel surface. On titanium alloy discs there was a significant increase in aluminum (p < 0.001) among all groups compared with medium only.

CONCLUSION

These results indicated that macrophages were able to attach to and affect the oxide surface of stainless steel and titanium alloy discs. Cite this article: Bone Joint J 2020;102-B(7 Supple B):116-121.

Retrieval Analysis of Modern Knee Tumor Megaendoprosthesis Shows Considerable Volumetric Metal Wear Generated at the Rotating Hinge

Frequently occurring damage, as well as elevated blood metal ion levels, are reported in relation to a tumor and revision system for total knee arthroplasty (TKA), which applies a rotating hinge coupling with a metal-on-metal (MoM) articulation. As the patient collective for this specific system is small, there is no data on wear generated from the couplings. In this study, wear volume and influencing parameters were investigated at 44 retrieved TKAs with MoM couplings. A scoring system rating frequently occurring abrasive wear between 0 (no wear) and 3 (distinct wear) was established. The wear score was correlated to time in vivo, bone resection length, patient weight and polyethylene inlay damage. Volumetric wear was estimated applying coordinate measurements. An elevated wear score of two or higher was found in 43% of cases. The mean wear rate accounted to 7.8 mm³/year. The main influencing coefficient for the extent of wear is time in vivo. We found a tendency for higher wear scores with higher inlay degradation scores. Patient weight and bone resection length did not impact coupling wear. Assessment of wear damage by a semi-quantitative scoring system has proven to be a reliable option for non-destructive coupling evaluation. The generated wear volume is high.