Do tissues from THA revision of highly crosslinked UHMWPE liners contain wear debris and associated inflammation?

In silico approaches for enhancing retrieval analysis as a source for discovery of implant reactivity-related mechanisms and biomarkers

The ability to characterize implant debris in conjunction with corresponding immune and tissue-destructive responses renders retrieval analysis as an important tool for evaluating orthopedic devices. We applied advanced analytics and in silico approaches to illustrate the retrieval-based potential to elucidate host responses and enable discovery of corresponding biomarkers indicative of in vivo implant performance. Hip retrieval analysis was performed using variables based on immunostaining, polarized microscopy, and fretting-corrosion and oxidation analyses. Statistical analyses were performed in R. Hierarchical/k-means clustering and principal component analysis were used for data analysis and visualization. Correlation Engine (CE) and Ingenuity Pathway Analysis (IPA) were employed for in silico corroboration of putative biomarkers. Higher giant cell and histiocyte scores and positivity for CD68 and CD3 indicating infiltration with macrophages and T-cells, respectively, were detected mainly among older generation hips with higher ultra-high-molecular-weight-polyethylene loads. Our in silico analysis using pre-existing data on wear particle-induced loosening substantiated the role of CD68 in implant-induced innate responses and identified the CD68-related molecular signature that can be indicative of development of aseptic loosening and can be further corroborated for diagnostic/prognostic testing in clinical setting. Thus, this study confirmed the great potential of advanced analytics and in silico approaches for enhancing retrieval analysis applications to discovery of new biomarkers for optimizing implant-related preclinical testing and clinical management. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:263-271, 2020.

CD11b promotes the differentiation of osteoclasts induced by RANKL through the spleen tyrosine kinase signalling pathway

Macrophage surface antigen‐1 (Mac‐1, CD11b/CD18) has been implicated in the regulation of osteoclastogenesis. In the synovial tissues of patients with aseptic loosening after total hip replacement, CD11b was up‐regulated, which indicated that CD11b is closely involved in osteolysis around the prosthesis. We found that CD11b, but not CD18, promoted osteoclast (OC) maturation. Here, we show CD11b up‐regulated the levels of spleen tyrosine kinase (Syk), c‐Fos and nuclear factor of activated T cells, cytoplasmic‐1 (NFATc1), as well as the activity of extracellular‐regulated kinase (Erk), and as a result, osteoclast precursors (OCPs) differentiated and became tartrate‐resistant acid phosphatase (TRAP)‐positive. In addition, increased tumour necrosis factor‐α (TNF‐α) induced by ultra‐high molecular weight polyethylene (UHMWPE) particles up‐regulated the level of CD11b. Taken together, these findings suggest that CD11b is a positive regulator of osteoclastogenesis and that it functions by activating the Syk signalling pathway, while CD18 does not have the same effect.

Contributions of human tissue analysis to understanding the mechanisms of loosening and osteolysis in total hip replacement

Aseptic loosening and osteolysis are the most frequent late complications of total hip arthroplasty (THA) leading to revision of the prosthesis. This review aims to demonstrate how histopathological studies contribute to our understanding of the mechanisms of aseptic loosening/osteolysis development. Only studies analysing periprosthetic tissues retrieved from failed implants in humans were included. Data from 101 studies (5532 patients with failure of THA implants) published in English or German between 1974 and 2013 were included. "Control" samples were reported in 45 of the 101 studies. The most frequently examined tissues were the bone-implant interface membrane and pseudosynovial tissues. Histopathological studies contribute importantly to determination of key cell populations underlying the biological mechanisms of aseptic loosening and osteolysis. The studies demonstrated the key molecules of the host response at the protein level (chemokines, cytokines, nitric oxide metabolites, metalloproteinases). However, these studies also have important limitations. Tissues harvested at revision surgery reflect specifically end-stage failure and may not adequately reveal the evolution of pathophysiological events that lead to prosthetic loosening and osteolysis. One possible solution is to examine tissues harvested from stable total hip arthroplasties that have been revised at various time periods due to dislocation or periprosthetic fracture in multicenter studies.

The role of oxidative stress in aseptic loosening of total hip arthroplasties

This study investigated the hypothesis that wear particle-induced oxidative stress initiates osteolysis after total hip arthroplasty (THA). Patient radiographs were scored for osteolysis and periprosthetic tissues were immunostained and imaged to quantify polyethylene wear, inflammation, and five osteoinflammatory and oxidative stress-responsive factors. These included high mobility group protein-B1 (HMGB1), cyclooxygenase-2 (COX2), inducible nitric oxide synthase (iNOS), 4-hydroxynonenal (4-HNE), and nitrotyrosine (NT). The results show wear debris correlated with inflammation, 4-HNE, NT and HMGB1, whereas inflammation only correlated with NT and HMGB1. Similar to wear debris and inflammation, osteolysis correlated with HMGB1. Additionally, osteolysis correlated with COX2 and 4-HNE, but not iNOS or NT. Understanding the involvement of oxidative stress in wear-induced osteolysis will help identify diagnostic biomarkers and therapeutic targets to prevent osteolysis after THA.

Polyethylene particles in joint fluid and osteolysis in revision total knee arthroplasty

BACKGROUND

One of the most frequent reasons for total knee arthroplasty late failure is osteolysis. It has been related to foreign body reaction to polyethylene particles. The aim of this study is to analyse the number, size and morphology of polyethylene particles in synovial fluid in total knee arthroplasty revision and correlate them to the pathology and the degree of osteolysis.

METHODS

Synovial fluid was obtained in 12 patients before the revision total knee arthroplasty. Polyethylene particles were isolated and analysed through scanning electron microscopy. Samples of synovial tissue were analysed with optical microscopy while considering the parameters of particles and histiocytic infiltration. Osteolysis was analysed with plain radiography and the macroscopic aspect during surgery.

RESULTS

The statistical analysis showed a significant correlation between a high concentration of polyethylene particles in synovial fluid and a high degree of osteolysis. The concentration of particles in synovial fluid also showed a significant correlation with a high degree of particles and histiocytes in the histological analysis. There was a relationship between the size of particles and the degree of osteolysis. No relationship was found between the shape of the particles and the histological findings or the degree of osteolysis.

CONCLUSIONS

In an "in vivo" TKA scenario, the presence of a high concentration of polyethylene particles in the synovial fluid seems to be the cause of a highly active foreign body histological reaction, with an increased number of histiocytes, which seems to be the cause of a significant degree of osteolysis around the implant.

Effect of component design in retrieved bipolar hip hemiarthroplasty systems

Primary articulation of bipolar hemiarthroplasty systems is at the femoral head-liner interface. The purpose of this study was to compare observed damage modes on 36 retrieved bipolar systems with implant, demographic, intraoperative, and radiographic data to elucidate the effects of component design, specifically locking mechanism, on clinical performance. Retrieved bipolar hip hemiarthroplasty systems of 3 different design types were obtained, disassembled, and evaluated macro- and microscopically for varying modes of wear, including abrasion, burnishing, embedding, scratching, and pitting. Clinical record review and radiographic analysis were performed by a senior orthopedic surgery resident. Average bipolar hip hemiarthroplasty system term of service was 46 months (range, 0.27-187 months). All devices contained wear debris captured within the articulating space between the femoral head and liner. In 31% of patients without infection, lucency was observed on immediate prerevision radiographs. The system with a leaf locking mechanism showed significantly increased radiographically observed osteolysis (P=.03) compared with a system with a stopper ring locking mechanism. In addition, implant design and observed damage modes, including pitting and third-body particle embedding, were significantly associated with radiographically observed osteolysis.

Highly crosslinked polyethylene does not reduce the wear in total knee arthroplasty: in vivo study of particles in synovial fluid

The aim was to assess if the reduction in polyethylene wear with highly crosslinked polyethylene suggested by studies with knee simulators is confirmed in patients with a knee arthroplasty. The use of a conventional or a highly crosslinked polyethylene was randomly assigned intraoperatively. Twelve months after surgery a knee arthrocentesis was performed and the synovial fluid of 17 patients in each group was studied analysing the number, size and shape of the polyethylene particles by scanning electron microscope. We found no significant differences in the concentration, size or morphology of polyethylene particles between groups. The great variability in the number of particles between individuals suggests that in vivo polyethylene wear depends on many factors and probably the type of polyethylene is not the most significant.

Pyrroloquinoline quinine inhibits RANKL-mediated expression of NFATc1 in part via suppression of c-Fos in mouse bone marrow cells and inhibits wear particle-induced osteolysis in mice

The effects of pyrroloquinoline quinine (PQQ) on RANKL-induced osteoclast differentiation and on wear particle-induced osteolysis were examined in this study. PQQ inhibited RANKL-mediated osteoclast differentiation in bone marrow macrophages (BMMs) in a dose-dependent manner without any evidence of cytotoxicity. The mRNA expression of c-Fos, NFATc1, and TRAP in RANKL-treated BMMs was inhibited by PQQ treatment. Moreover, RANKL-induced c-Fos and NFATc1 protein expression was suppressed by PQQ. PQQ additionally inhibited the bone resorptive activity of differentiated osteoclasts. Further a UHMWPE-induced murine calvaria erosion model study was performed to assess the effects of PQQ on wear particle-induced osteolysis in vivo. Mice treated with PQQ demonstrated marked attenuation of bone erosion based on Micro-CT and histologic analysis of calvaria. These results collectively suggested that PQQ demonstrated inhibitory effects on osteoclast differentiation in vitro and may suppress wear particle-induced osteolysis in vivo, indicating that PQQ may therefore serve as a useful drug in the prevention of bone loss.

[Polyethylene particles in synovial fluid after knee arthroplasty with a conventional or highly cross-linked polyethylene. Preliminary study]

AIM OF THE STUDY

In recent years cross-linked polyethylenes have been developed in an attempt to reduce the wear, as has been demonstrated in knee simulators. The aim is to assess, by counting particles of polyethylene in synovial fluid, whether the reduction in wear is confirmed in patients with a highly crosslinked polyethylene prosthesis.

MATERIAL AND METHODS

A prospective randomised study was designed. During the implantation of a knee prosthesis, one group of patients was assigned the use of a conventional polyethylene (group A), and the other group a highly crosslinked polyethylene (X3, Stryker Orthopaedics) (group B). At 12 months after surgery a knee arthrocentesis was performed, and the number of polyethylene particles was counted in a scanning electron microscopy. Fourteen samples from each group were studied.

RESULTS

Both groups were comparable in all study variables. We found no significant differences in the concentration of polyethylene particles/ml (1.49 ± 0.85 million in group A vs 1.42 ± 0.91 million in group B, P=.60) or the total number of isolated particles. We found no differences either in size or morphology of particles between both groups.

DISCUSSION AND CONCLUSIONS

Although several in vitro studies in vitro using different types of highly crosslinked polyethylene found a significant reduction, we did not find that that wear was reduced in the knees of these patients. The great variability in the number of particles between individuals suggests that polyethylene wear in vivo depends on many factors, so perhaps the type of polyethylene is not the most significant factor.

The aqueous extract of Angelica sinensis, a popular Chinese herb, inhibits wear debris-induced inflammatory osteolysis in mice

BACKGROUND

More and more studies have shown Angelica sinensis' (AS) therapeutic action on chronic inflammatory diseases in recent years. We investigated effects of aqueous extract of AS on inflammatory cytokines release and wear debris particles-induced osteolysis.

MATERIALS AND METHODS

Ultra high molecular weight polyethylene (UHMWPE) particles were used to induce inflammation in RAW264.7 cell and C57BL/J6 mice. AS extract was obtained through a series of purification steps, and divided into high dose group and low dose group during the research of cell culture, tissue culture, and animal treatment. After 72 h culture with optimal particles, supernatants were collected for cytokine analysis. Calvaria were harvested from the mice model after 10 d treatment with the AS extract. Six calvaria of each group were cultured into medium for 72 h for analyzing cytokine generated in vivo. Histologic analyses and micro-computed tomography (micro-CT) scan were used to determine osteoclastogenesis and inflammatory bone resorption.

RESULTS

Concentration of tumor necrosis-alpha (TNF-α) and interleukin-1beta (IL-1β) was significantly attenuated by AS extract both in vitro and in vivo. The osteolysis area and the osteoclast numbers were decreased from 0.406 ± 0.0799 to 0.117 ± 0.0103 mm(2), and from 22.7 ± 5.0 to 11.3 ± 1.8, respectively (P < 0.01). Compared with the control group, the protection effects of AS extract was further confirmed with data of the more accurate 3-dimension micro-CT reconstruction.

CONCLUSIONS

This study suggests a potential resolution of inhibiting wear debris particles-induced inflammatory bone resorption, as well as a possible way of inhibiting aseptic loosening after joint replacement surgery.