Cytotoxicity and macrophage cytokine release induced by ceramic and polyethylene particles in vitro

Characterization of residual debris on packaged hip arthroplasty stems demonstrates the dominance of less than 10 μm sized particulate: Updated USP788 guidelines for orthopedic implants

Past evaluation of particle contamination on packaged implants has typically been conducted using US Pharmacopeia (USP) 788, a 1970s pharmaceutical guideline created to evaluate contaminant particles in injectable fluids and syringes. Our objective was to reestablish relevant acceptance criteria for residual orthopedic and other implant debris, including smaller particles (i.e., <10 μm in diameter). Packaged total hip arthroplasty (THA) titanium (Ti6Al4V)-alloy femoral stems were used (hydroxyapatite [HA]-coated and non-coated stems). Short-term ultrasonication and longer-term 24-hour soak/agitation methods were used to elute surface-bound contaminant particles, and released particles were analyzed via scanning electron microscopy, energy-dispersive x-ray analysis, image analysis, and particle characterization. For HA-coated THA-stems, >99% of eluted particles were calcium phosphate. For plain non-coated THA-stems, >99% of eluted particles were titanium-alloy-based. The number-based median size of particles in both groups was approximately 1.5 μm in diameter despite being composed of different materials. The total volume of particulate removed from HA-coated stems was 0.037 mm3 (671 × 103 particles total), which was approximately >50-fold more volume than that on plain non-coated stems at 0.0006 mm3 (89 × 103 particles total). Only non-coated THA stems passed reestablished USP788 acceptance criteria, compared by using equivalent total volumes of contaminant particulate within new and legacy guideline ranges of >10 and >25 μm ECD, that is, <1.0 × 107 particles for <1 μm diameter in size, <600,000 for <1-10 μm, <6000 for 10-25 μm and <600 for >25 μm. These results fill a knowledge gap on how much residual debris can be expected to exist on packaged implants and can be used as a basis for updating acceptance criteria (i.e., termed USP788-Implant [USP788-I]). Residual implant particulate assessment is critical given the increasing implant complexity and new manufacturing techniques (e.g., additive manufacturing).

Aluminum Nanoparticles Affect Human Platelet Function In Vitro

Endoprostheses are prone to tribological wear and biological processes that lead to the release of particles, including aluminum nanoparticles (Al NPs). Those particles can diffuse into circulation. However, the toxic effects of NPs on platelets have not been comprehensively analyzed. The aim of our work was to investigate the impact of Al NPs on human platelet function using a novel quartz crystal microbalance with dissipation (QCM-D) methodology. Moreover, a suite of assays, including light transmission aggregometry, flow cytometry, optical microscopy and transmission electron microscopy, were utilized. All Al NPs caused a significant increase in dissipation (D) and frequency (F), indicating platelet aggregation even at the lowest tested concentration (0.5 µg/mL), except for the largest (80 nm) Al NPs. A size-dependent effect on platelet aggregation was observed for the 5-20 nm NPs and the 30-50 nm NPs, with the larger Al NPs causing smaller increases in D and F; however, this was not observed for the 20-30 nm NPs. In conclusion, our study showed that small (5-50 nm) Al NPs caused platelet aggregation, and larger (80 nm) caused a bridging-penetrating effect in entering platelets, resulting in the formation of heterologous platelet-Al NPs structures. Therefore, physicians should consider monitoring NP serum levels and platelet activation indices in patients with orthopedic implants.

Third-Generation Ceramic-on-Ceramic Total Hip Arthroplasty in Patients with Osteonecrosis of the Femoral Head: A 10- to 16-year Follow-up Study

BACKGROUND

Long-term follow-up results of ceramic-on-ceramic (COC) total hip arthroplasty (THA), specifically, in patients with osteonecrosis of the femoral head (ONFH) are unknown. We evaluated (1) clinical results and radiological outcomes, (2) ceramic-related complications: noise and ceramic fracture, (3) osteolysis, and (4) survivorship after alumina COC THA in ONFH patients with longer than 10-year follow-up.

METHODS

From May 2003 to June 2009, 325 ONFH patients (403 hips) underwent primary THAs at our department. Among them, 231 patients (293 THAs) were followed for 10 to 16 (mean, 12.9) years. There were 148 men and 83 women, their mean age at the time of THA was 47.2 years, and their mean body index was 24.0 kg/m2. The postoperative CT scans were done in 160 hips.

RESULTS

Grinding sensation or squeak was noted in 6.8% (20/293), ceramic head fracture occurred in 2.4% (7/293) and acetabular osteolysis developed in 0.7% (2/293). All 7 ceramic fractures occurred in 28-mm short-neck heads. There was no detectable wear or prosthetic loosening, and the 16-year survivorship was 96.0% (95% confidence interval; 93.8% to 98.2%). The mean Harris hip score was 91.7 (range, 84 to 100) points at the final follow-up.

CONCLUSIONS

The 10- to 16-year results of alumina COC THAs were encouraging with an excellent survivorship. However, ceramic fracture and noise still remain matters of concern. We recommend not to use 28-mm short-neck ceramic head to avoid ceramic head fractures.

LEVEL OF EVIDENCE

III.

Particulate Debris Released From Breast Implant Surfaces Is Highly Dependent on Implant Type

BACKGROUND

Although breast implants (BIs) have never been safer, factors such as implant debris may influence complications such as chronic inflammation and illness such as ALCL (anaplastic large cell lymphoma). Do different types of BIs produce differential particulate debris?

OBJECTIVES

The aim of this study was to quantify, investigate, and characterize the size, amount, and material type of both loosely bound and adherent surface particles on 5 different surface types of commercial BIs.

METHODS

Surface particles from BIs of 5 surface types (n = 5/group), Biocell, Microcell, Siltex, Smooth, SmoothSilk, and Traditional-Smooth, were: (1) removed by a rinsing procedure and (2) removed with ultrapure adhesive carbon tabs. Particles were characterized (ASTM 1877-16) by scanning electron microscopy and energy-dispersive X-ray chemical analysis.

RESULTS

Particles rinsed from Biocell, Microcell and Siltex were <1 μm in diameter whereas SmoothSilk and Traditional-Smooth surfaces had median sizes >1 μm (range, 0.4-2.7 μm). The total mass of particles rinsed from the surfaces indicated Biocell had >5-fold more particulate compared with all other implants, and >30-fold more than SmoothSilk or Traditional-Smooth implants (>100-fold more for post-rinse adhesion analysis). Energy-dispersive X-ray analysis indicated that the particulate material for Biocell, Microcell, and Siltex was silicone (>50%), whereas particulates from SmoothSilk and Traditional-Smooth implants were predominantly carbon-based polymers, eg, polycarbonate-urethane, consistent with packaging (and were detected on all implant types). Generally, SmoothSilk and Traditional-Smooth implant groups released >10-fold fewer particles than Biocell, Microcell, and Siltex surfaces. Pilot ex vivo tissue analysis supported these findings.

CONCLUSIONS

Particulate debris released from BIs are highly dependent on the type of implant surface and are a likely key determinant of in vivo performance.

LEVEL OF EVIDENCE: 5

Heel Complications

Postoperative complications can be burdensome on both the patient and the surgeon. Attention in literature is often directed toward different forms of treatment and successful outcomes in surgery. The incentive of this article is to bring insight toward postoperative complications in rearfoot surgery, more specifically, the repair of the Achilles tendon with suture tape and suture anchors. This article directs attention to the recent reports on hypersensitivity reactions seen with the use of suture tape and nonabsorbable suture anchors and may encourage physicians to make patients aware of this potential complication when using these materials.

Does load-bearing materials influence hip capsule thickness in total hip replacement? An MRI case-matched study

BACKGROUND

Ceramic-on-ceramic (COC) total hip replacements (THR) have exhibited less instability and late dislocation. Hip capsule plays an important role in hip stability. Different surrounding soft tissue reactions have been observed according to the bearing material used but no study compared these data using MRI investigation. Therefore, we performed a retrospective case control study to compare hip capsule thicknesses according to the bearing materials in THR and in native hips.

HYPOTHESIS

Hip capsule is thicker after COC THR compared to ceramic- or metal-on-polyethylene (PE) bearings, or native hips.

MATERIALS AND METHOD

Magnetic resonance imaging (MRI) images, combined with a multi acquisition variable resonance image combination (MAVRIC) sequence, was used to measure the hip capsule thickness in 16 patients (29 hips) who had either COC (13 hips, median age at surgery: 64.8 years old, median follow-up at imaging: 2482 days), PE bearings (11 hips, median age at surgery: 48.4 years old (significantly different from COC THR), median follow-up at imaging: 1860 days (NS)), or a native hip with no implant (5 hips). Two independent radiologists measured capsular thicknesses in 4 different zones and were blinded regarding the bearing components. The imaged hips were classified into three groups: native, COC and PE.

RESULTS

The COC THR group had the thickest capsules (median 7.0mm, range 2.9-15.5mm). This result was statistically significant (p<0.0001) when compared to PE THR (median 4.9mm, range 2.2-10.5mm), and to native hips (median 4.1mm, range 2.7-6.9mm) measurements, respectively. Furthermore, painful hips had thinner capsules (4.6mm, range 2-10.5) compared to not painful hips (6.8mm, range 2.3-15.5) (p=0.0006).

DISCUSSION

This is the first in-vivo study measuring capsular thickness in THR with the objective of measuring variations according to the hip implant materials used. The results revealed a significantly thicker capsule for the COC bearing compared to either PE or native hips, and a thinner capsule in painful hips.

LEVEL OF EVIDENCE

III, retrospective non-consecutive cohort study.

Adverse Reaction to Zirconia in a Modern Total Hip Arthroplasty with Ceramic Head

Hypersensitivity reactions to zirconia (ZrO2) or similar ceramics is highly unusual. Owing to the stable oxide formed between the base metal and oxygen, ceramics are considered relatively biologically inert. We report the case of an otherwise healthy 50-year-old woman with a 5-year history of progressively worsening right hip pain who underwent a ceramic-on-polyethylene total hip replacement and subsequently developed hypersensitivity reaction. After metal allergy testing showed her to be highly reactive to zirconium, the femoral head was revised to a custom titanium implant and her symptoms resolved.

Alumina Ceramic Exacerbates the Inflammatory Disease by Activation of Macrophages and T Cells

(1) Background: Aluminum oxide (Al₂O₃) ceramic is one of the materials used for artificial joints, and it has been known that their fine particles (FPs) are provided by the wear of the ceramic. Al₂O₃ FPs have been shown to induce macrophage activation in vitro; however, the inflammatory effect in vivo has not been studied. (2) Methods: We examined the in vivo effect of Al₂O₃ FPs on the innate and adaptive immune cells in the mice. (3) Results: Al₂O₃ FPs promoted the activation of spleen macrophages; however, conventional dendritic cells (cDCs), plasmacytoid DCs (pDCs), and natural killer (NK) cells were not activated. In addition, increases in the CD4 and CD8 T cells was induced in the spleens of the mice treated with Al₂O₃ FPs, which differentiated into interferon-gamma (IFN-γ)-producing helper T1 (Th1) and cytotoxic T1 (Tc1) cells. Finally, the injection of Al₂O₃ FPs exacerbated dextran sulfate sodium (DSS)-induced inflammation in the colon, mediated by activated and increased number of CD4 and CD8 T cells. (4) Conclusions: These data demonstrate that FPs of Al₂O₃ ceramic may contribute to the exacerbation of inflammatory diseases in the patients.

The Inflammatory Effects of Breast Implant Particulate Shedding: Comparison With Orthopedic Implants

Currently, there is a dearth of information regarding the degree of particle shedding from breast implants (BIs) and what are the general biological consequences of BI debris. Thus, it is unclear to what degree BI debris compromises the long-term biological performance of BIs. For orthopedic implants, it is well established that the severity of biological reactivity to implant debris governs long-term clinical performance. Orthopedic implant particulate debris is generally in the range of 0.01 to 100 μm in diameter. Implant debris-induced bioreactivity/inflammation is mostly a peri-implant phenomenon caused by local innate immune cells (eg, macrophages) that produce proinflammatory cytokines such as tumor necrosis factor-α, interleukin-1β, interleukin-6, and prostaglandin 2 (PGE2). In orthopedics, there have been few systemic concerns associated with polymeric implant debris (like silicone) other than documented dissemination to remote organs (eg, liver, spleen, etc.) with no known associated pathogenicity. This is not true of metal implant debris where normal (well-functioning) implants can induce systemic reactions such as delayed type hypersensitivity. Diagnostic analysis of orthopedic tissues has focused on innate (macrophage mediated) and adaptive (lymphocyte-mediated hypersensitivity) immune responses. Orthopedic implant debris-associated lymphocyte cancers have not been reported in over 40 years of orthopedic literature. Adaptive immune responses such as hypersensitivity reactions to orthopedic implant debris have been dominated by certain implant types that produce specific kinds of debris (eg, metal-on-metal total joint prostheses). Orthopedic hypersensitivity responses and atypical BI bioreactivity such as BI-associated anaplastic large cell lymphoma share crossover markers for diagnosis. Differentiating normal innate immune reactivity to particles from anaplastic large cell lymphoma reactions from delayed type hypersensitivity reactions to BI-associated implant debris remains unclear but vital to patients and surgeons.

High prevalence of noise following Delta ceramic-on-ceramic total hip arthroplasty

Aims

We evaluated the short-term functional outcome and prevalence of bearing-specific generation of audible noise in 301 patients (336 hips) operated on with fourth generation (Delta) medium diameter head, ceramic-on-ceramic (CoC) total hip arthroplasties (THAs).

Patients and Methods

There were 191 female (63%) and 110 male patients (37%) with a mean age of 61 years (29 to 78) and mean follow-up of 2.1 years (1.3 to 3.4). Patients completed three questionnaires: Oxford Hip Score (OHS), Research and Development 36-item health survey (RAND-36) and a noise-specific symptom questionnaire. Plain radiographs were also analysed. A total of three hips (0.9%) were revised.

Results

There were 52 patients (54 hips, 17%) who reported noise, and in 25 (48%) of them the noise was frequently heard. In the multiple regression analysis, the only independent risk factor for noise was a specific THA brand, with a threefold increased risk (95% confidence intervals 1.39 to 6.45, p = 0.005) of noise compared with the reference THA brand. Patients with noisy hips had lower median OHS (43 versus 46.5, p = 0.002) and their physical functioning (p = 0.021) subscale in RAND-36 was reduced.

Conclusion

Noise was surprisingly common in this population. Cite this article: Bone Joint J 2017;99-B:44–50.

Soluble and particulate Co-Cr-Mo alloy implant metals activate the inflammasome danger signaling pathway in human macrophages: a novel mechanism for implant debris reactivity

Immune reactivity to soluble and particulate implant debris remains the primary cause of aseptic inflammation and implant loosening. However, the intracellular mechanisms that trigger immune cells to sense and respond to exogenous nonbiological agents such as metal particles or metal ions released from orthopedic implants remain unknown. Recent studies in immunology have outlined the importance of the intracellular inflammasome complex of proteins in sensing danger/stress signals triggered by nonbiological agents in the cytosol of macrophages. We hypothesized that metal implant debris can activate the inflammasome pathway in macrophages that causes caspase-1-induced cleavage of intracellular pro-IL-1beta into its mature form, resulting in IL-1beta secretion and induction of a broader proinflammatory response. We tested this hypothesis by examining whether soluble cobalt, chromium, molybdenum, and nickel ions and Co-Cr-Mo alloy particles induce inflammasome- mediated macrophage reactivity. Our results demonstrate that these agents stimulate IL-1beta secretion in human macrophages that is inflammasome mediated (i.e., NADPH-, caspase-1-, Nalp3-, and ASC-dependent). Thus, metal ion- and particle-induced activation of the inflammasome in human macrophages provides evidence of a novel pathway of implant debris-induced inflammation, where contact with implant debris is sensed and transduced by macrophages into a proinflammatory response.

Ceramic liner fracture after cementless alumina-on-alumina total hip arthroplasty

Advances in technology have reduced the risk of fracture of ceramic total hip arthroplasty implants, but concerns remain about fracture of both components. We retrospectively reviewed 133 patients (157 hips) who had cementless alumina-on-alumina total hip arthroplasties with a sandwich-type acetabular component. Six patients (seven hips) died and five patients (six hips) were interviewed by telephone (95% followup). The 122 patients (144 hips) examined had a minimum followup of 36 months (average, 45 months; range, 36-68 months). All acetabular cups and femoral stems were radiographically stable at the last followup. Five hips in five patients (3.5%) were revised because of ceramic liner fractures. Ceramic liner fractures occurred at a mean of 35 months (range, 24-48 months) postoperatively. Acetabular cups in the fracture group (n = 5) were more anteverted than those in the nonfracture group (n = 139). In three patients the fracture apparently occurred during squatting, resulting in hyperflexion and wide hip abduction. Early ceramic liner fracture was associated with impingement associated with excessive anteversion of the acetabular cup in Korean patients who habitually squat.

Comparative surface examinations on corund blasted titanium implants and explants in total hip arthroplasty

INTRODUCTION

Blasting techniques using corundum to create rough surfaces are used in many different processes for the surface treatment of hip implants. Recent evidence points an association between residual particles and early loosenings in the sense of third-body wear.

MATERIALS AND METHOD

The surfaces of five unused, original-packaged CLS stems and ARR-Titan supporting rings, respectively, were compared with five explanted CLS stems and ARR-Titan supporting rings.

RESULTS

The surface of the ARR-Titan supporting rings was adhered to Al2O3 particles at 23.2+/-2.5% on the implants and 12.3+/-3.0% on the explants (P < 0.0001). For the CLS stem, the surface to which Al2O3 particles adhered was 16.4+/-2.2 % on the implants, whereas the surface to which Al2O3 particles adhered was 12.4+/-3.3% on the explants (P = 0.0275).

DISCUSSION

The results of this study show that corundum particles can be found to cover a high percentage on rough-blasted titanium surfaces of ready-to-use devices. In contrast, this contamination is significantly less on the explants treated in an identical fashion prior to implantation.

Particles of all sizes provoke inflammatory responses in vivo

The aim of this study was to investigate whether all sizes of wear particles are capable of provoking inflammatory responses and whether there are different responses among different particle sizes. The knees of 40 female Balb/c mice were injected with polystyrene particles of three different diameters, 0.5 microm, 2.0 microm, and 75 microm, using a 0.1% vol/vol concentration. Seven days after particle injection, assessment of the synovial microcirculation using intravital microscopy, and histologic examination, were done. All the mice injected with polystyrene particles had enhanced leukocyte-endothelial cell interactions and histologic scores regardless of particle size when compared with control animals injected with sterile phosphate buffered saline. Polystyrene particles 0.5 microm in size provoked stronger membrane thickening and increased leukocyte-endothelial cell interactions than 75-microm particles. The fraction of rolling leukocytes was enhanced in the 2.0-microm particle group when compared with the 75-microm particle group. These results indicate that polystyrene particles of all sizes (0.5 microm, 2.0 microm, and 75 microm) are capable of inducing an inflammatory response. Small particles (0.5 microm, 2.0 microm) seem to provoke a stronger inflammatory response than larger particles (75 microm) in conditions with equal particle volume.

Ceramics in total hip replacement

Alumina-on-alumina total hip arthroplasty has been used for 32 years in Europe. The theoretical advantages of this combination are represented by its remarkable sliding characteristics, its very low wear debris generation, and its improved fracture toughness. These advantages are achieved if the material is processed properly with high density, high purity and small grains. We summarize the results obtained with the alumina-on-alumina combination concerning in vitro and in vivo wear behavior with special emphasis on wear debris characterization and quantification and histologic tissue examinations. Alumina-on-alumina seems to be one of the best choices in young and active patients provided that sound socket fixation is maintained in the long term.

Ceramic-on-ceramic bearings in total hip arthroplasty

The ideal bearing surface for total hip arthroplasty still is being sought. This bearing would be durable, cost-effective, easy to implant, inert, and produce minimal wear debris. Ceramic-on-ceramic bearings have continued to evolve and have enjoyed success in many European centers throughout the past 3 decades. A limited number of early reports from the United States discouraged widespread acceptance and use of ceramic-on-ceramic total hip arthroplasty. Once critically analyzed most of the failures from the early reports are attributable to design and material specific flaws. Vast improvements have been made in ceramic manufacturing leading to even more superior wear characteristics and higher burst strengths. The case for alumina-on-alumina ceramic bearings is becoming stronger as data accumulate clinically and in vitro. In a multicenter, prospective and randomized study, an alumina-on-alumina ceramic bearing is compared with a cobalt chrome-on-polyethylene bearing. After as many as 48 months there has been no significant difference in clinical performance between the two study groups. No ceramic head fracture or ceramic bearing failure has occurred. Therefore, this new alumina-on-alumina ceramic bearing is a safe option for total hip arthroplasty and may provide a more durable prosthesis especially in young and active patients.