Cytokine levels in synovial fluid from hips with well-functioning or loose prostheses

The effect of TNF-α on osteoblasts in metal wear-induced periprosthetic bone loss

Aims

This study aimed to examine the effects of tumour necrosis factor-alpha (TNF-α) on osteoblasts in metal wear-induced bone loss.

Methods

TNF-α immunoexpression was examined in periprosthetic tissues of patients with failed metal-on-metal hip arthroplasties and also in myeloid MM6 cells after treatment with cobalt ions. Viability and function of human osteoblast-like SaOs-2 cells treated with recombinant TNF-α were studied by immunofluorescence, terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNEL) assay, western blotting, and enzyme-linked immunosorbent assay (ELISA).

Results

Macrophages, lymphocytes, and endothelial cells displayed strong TNF-α immunoexpression in periprosthetic tissues containing metal wear debris. Colocalization of TNF-α with the macrophage marker CD68 and the pan-T cell marker CD3 confirmed TNF-α expression in these cells. Cobalt-treated MM6 cells secreted more TNF-α than control cells, reflecting the role of metal wear products in activating the TNF-α pathway in the myeloid cells. While TNF-α did not alter the immunoexpression of the TNF-receptor 1 (TNF-R1) in SaOs-2 cells, it increased the release of the soluble TNF-receptor 1 (sTNF-R1). There was also evidence for TNF-α-induced apoptosis. TNF-α further elicited the expression of the endoplasmic reticulum stress markers inositol-requiring enzyme (IRE)-1α, binding-immunoglobulin protein (BiP), and endoplasmic oxidoreductin1 (Ero1)-Lα. In addition, TNF-α decreased pro-collagen I α 1 secretion without diminishing its synthesis. TNF-α also induced an inflammatory response in SaOs-2 cells, as evidenced by the release of reactive oxygen and nitrogen species and the proinflammatory cytokine vascular endothelial growth factor.

Conclusion

The results suggest a novel osteoblastic mechanism, which could be mediated by TNF-α and may be involved in metal wear debris-induced periprosthetic bone loss.

Cite this article: Bone Joint Res 2020;9(11):827–839.

Innate immune response and implant loosening: Interferon gamma is inversely associated with early migration of total knee prostheses

To allow prediction of the risk of loosening prior to surgery, we investigated the relationship between innate immune cytokine response via TLR2 stimulation and early migration of six different knee prostheses using RSA (radiostereometry). This study included 114 patients of a prospective RSA-cohort who received a total knee arthroplasty. Whole blood cytokine responses were obtained by ex vivo stimulation with tripalmitoyl-S-glycerylcysteine (Pam3Cys-SK4) for assessment of the TLR2 immune response. Early migration was calculated using the maximum total point motion (MTPM) 1 year post surgery. Principal component analysis (PCA) was applied to the cytokine data to reduce the correlated data of individual cytokines and identified two components. Subsequently, linear mixed model analyses were applied with adjustments for gender, age, BMI, time-to-blood sampling, and prosthesis type. Component 1, consisting of IFNγ, IL-12p40, IL-10, IL-1β, TNFα, and IL-6, showed a significant inverse association (β = -0.128; p = 0.041) with MTPM. Further analysis showed that IFNγ (β = -0.161, p = 0.008) had the highest contribution to this association and is particularly found in patients receiving another prosthesis than Nexgen (β = -0.239; p < 0.001). In conclusion, patients with high levels of IFNγ upon stimulation of TLR2 are at lower risk of early migration of their knee prosthesis.

Are there biological markers for wear or corrosion? A systematic review

BACKGROUND

Identification of biomarkers associated with wear and tribocorrosion in joint arthroplasty would be helpful to enhance early detection of aseptic loosening and/or osteolysis and to improve understanding of disease progression. There have been several new reports since the last systematic review (which covered research through mid-2008) justifying a new assessment.

QUESTIONS/PURPOSES

We sought to determine which biomarkers have the most promise for early diagnosis and monitoring of aseptic loosening and/or osteolysis related to wear or corrosion in total joint arthroplasty.

METHODS

We performed a systematic review using MEDLINE and EMBASE databases, covering the period through December 2013, and identified 1050 articles. We restricted the definition of biomarker to biomolecules and imaging parameters useful for diagnosis and monitoring of disease progression, only including articles in English. We chose 65 articles for full review, including 44 from the original search and 21 from subsequent hand searches. We used the 22 articles in which patients with total joint arthroplasty who had aseptic loosening and/or periimplant osteolysis unrelated to sepsis had been compared with patients with total joint arthroplasty with stable implants. There were 90 comparisons of these two patient populations involving 35 different biomarkers.

RESULTS

Diagnostic accuracy was assessed in nine of the 90 comparisons with the highest accuracy found for tartrate-resistant acid phosphatase 5b (0.96), although a separate comparison for this biomarker found a lower accuracy (0.76). Accuracy of > 0.80 was also found for crosslinked n-telopeptide of type I collagen, osteoprotegerin, and deoxypyridinoline. The most studied markers, tumor necrosis factor-α and interleukin-1β, were found to differ in the affected and control groups in < 30% of the comparisons. Thirty of the 35 biomarkers were studied in four or fewer separate comparisons with nearly half of the biomarkers (17) studied in only one comparison. Many of the comparisons were not able to eliminate a number of confounding variables, and there was only one prospective study.

CONCLUSIONS

Currently, there are no validated biomarkers for early diagnosis and monitoring of the biological sequelae of wear or tribocorrosion, although there are some promising leads, including markers of bone turnover.

Clinical and microbiological findings in prosthetic joint replacement due to aseptic loosening

OBJECTIVES

A role for microorganisms in aseptic prosthetic loosening (AL) is postulated. We analyse the microbiological and clinical findings of patients with suspected AL, and compare them with patients with chronic prosthetic joint infection (PJI).

METHODS

Prospective study (2011-2012) of patients with presumed AL. Evaluation of tissue samples (≥5; TS) at the time of surgery and sonication fluid (SF) of prosthesis.

RESULTS

According to positive culture in TS/SF, 89 patients were divided into: Group1: (≥2 positive-TS; n = 12); Group2: single positive-TS and concordant SF (n = 10); Group3: one positive or non-concordant TS or SF (n = 38); and Group4: cultures negative (n = 29). Positive-SF was always concordant with TS in Group 1 (75%); it was positive in 74% in Group 3. Median months (prosthesis-age: implantation to revision arthroplasty) for PJI and Group 1-4 was 21, 46, 65, 63 and 81, respectively (P < 0.001); they also had a different dynamic trend in prosthesis failure (P < 0.001).

CONCLUSIONS

Several patients with suspected AL are misdiagnosed PJI. Results from SF correlated well with TS in Group 1, led us to consider single positive-TS as significant (Group 2) and to suggest that microorganisms were on the prosthesis (Group 3). We observed a correlation between microbiology and prosthesis-age, which supports that early loosening is more often caused by hidden PJI than late loosening.

Polyethylene particles stimulate expression of ITAM-related molecules in peri-implant tissues and when stimulating osteoclastogenesis in vitro

Wear particle-induced orthopaedic prosthesis loosening is associated with elevated osteoclast activity. The immunoreceptor tyrosine-based activation motif (ITAM)-related molecules OSCAR, FcRγ, TREM2 and DAP12 are important for osteoclast formation. The aim of this study was to determine if these molecules are involved in peri-implant loosening by investigating their expression in peri-implant tissues obtained at revision of joint replacement components containing polyethylene (PE) wear particles, and in osteoclasts formed in vitro in the presence of PE particles. The results showed that there was a marked and statistically significant increase in protein levels of the ITAM-related molecules in the revision tissues. The levels of OSCAR, FcRγ, TREM2 and DAP12 mRNA in the revision tissues were also increased. In vitro PE particles stimulated osteoclast resorption in the presence of 50 ng ml(-1) receptor activator NFκB (RANKL) and significantly elevated the expression of OSCAR, FcRγ, TREM2 and DAP12 during osteoclast formation. These findings suggest that the ITAM signalling molecules and their co-receptors have a role in pathogenic bone loss associated with implant PE wear.

Bacterial wound contamination during simple and complex spinal procedures. A prospective clinical study

BACKGROUND CONTEXT

Spinal procedures have a potential of intraoperative contamination. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) have been used to diagnose postoperative infections after spinal surgery. However, it has not been demonstrated if there is an association between surgical site contamination and clinical manifestation of postoperative infection based on inflammatory markers and patients' clinical course.

PURPOSE

The purpose of this prospective study was to evaluate the association between surgical site contamination and the development of a postoperative infection in simple and complex surgical procedures. C-reactive protein and ESR levels were observed. The correlation between their values, surgical time, type of surgical procedures, and contaminated surgical sites was investigated.

STUDY DESIGN

Prospective clinical study.

PATIENT SAMPLE

The study consisted of 40 patients divided into two groups. Group A included 20 patients (mean age, 46.2 years; 12 women and 8 men) who underwent an open discectomy for a lumbar herniated disc. Group B consisted of 20 patients (mean age, 67.9 years; 11 women and 9 men) who underwent a decompression and instrumented fusion for lumbar spinal stenosis. They were followed up for an average of 26.7 months (range, 11-40 months).

OUTCOME MEASURES

Samples were obtained for cultures in standard time intervals during surgery. The types of bacteria cultured were evaluated, and CRP and ESR levels were measured.

METHODS

Simple lumbar discectomy (Group A, 20 patients) and instrumented lumbar decompression for degenerative lumbar stenosis (Group B, 20 patients) were performed in a prospective consecutive series of patients. All patients were operated by the same surgeon in the same operating room. Surgical site preparation in each patient was done by a standard manner. Samples were obtained for cultures in standard time intervals during surgery. C-reactive protein and ESR levels were measured preoperatively on the 3rd, 7th, and 21st postoperative days, and the clinical course of each patient was recorded.

RESULTS

From 40 patients, three patients in Group A and five patients in Group B, a total of eight patients (20%) had positive cultures for bacteria. There was no statistical significance between contamination and duration of surgery in both groups. None of the patients with positive intraoperative cultures developed any clinical signs of superficial or deep postoperative spinal infection, and no additional antibiotic treatment was administered. Three patients with negative cultures developed a postoperative infection. There were no differences in CRP and ESR values between patients with contamination and noncontamination in both groups. C-reactive protein and ESR levels were significantly elevated in complex procedures (Group B) than in simple procedures (Group A). Statistical analysis of CRP and ESR values in both groups and types of bacteria cultured intraoperatively are presented.

CONCLUSIONS

The results of this study demonstrate that intraoperative contamination can occur during simple and complex spinal procedures. In the absence of postoperative signs of infection in patients with intraoperative contamination, there is no need of continuing antibiotic treatment. Postoperative kinetics of CRP and ESR showed to be the same in patients with and without intraoperative contamination. Higher levels of inflammatory markers were noted in complex spinal procedures where instrumentation was applied.

Biomarkers in arthroplasty: a systematic review

We performed a systematic review of all MEDLINE-published studies of biomarkers in arthroplasty. Thirty studies met the inclusion criteria; majority evaluated biomarkers for osteolysis, aseptic prosthetic loosening, and prosthetic infections. Four studies reported an elevated Cross-linked N-telopeptides of type I collagen (urine or serum) in patients with osteolysis or aseptic prosthetic loosening when compared to appropriate controls. Two or more studies each found elevated C-reactive protein, erythrocyte sedimentation rate, and interleukin-6 in patients with infected prosthetic joints compared to controls. Most other biomarkers were either examined by single studies or had inconsistent or insignificant associations with outcomes. We conclude that the majority of the biomarkers currently lack the evidence to be considered as biomarkers for arthroplasty outcomes. Further studies are needed.

Severe osteolysis and soft tissue mass around total hip arthroplasty: description of four cases and review of the literature with respect to clinico-radiographic and pathologic differential diagnosis

Periprosthetic osteolysis is a well known phenomenon caused by wear particle-induced bone resorption, particularly common and extensively reported in total hip arthroplasty. Its typical radiographic feature is a radiolucent area adjacent to an implant, sometimes associated with a soft tissue mass. Osteolytic changes may be caused by numerous other pathologic processes, including infection, metabolic disease, and neoplasia. Four cases of massive periprosthetic bone destruction associated with a large soft tissue mass around a failed total hip replacement are presented. In three cases, a diagnosis of periprosthetic osteolysis was correctly made and managed by revision surgery. However, in one case angiosarcoma of the ipsilateral hemipelvis went long unrecognized despite aggressive clinical course, requiring hind-quarter amputation and ultimately resulting in the patient's death. Periprosthetic malignancy in the form of either primary sarcoma or metastatic cancer is a very rare yet reported event in the setting of previous hip replacement, likely leading to catastrophic consequences when diagnosis is not established in a timely manner. The differential diagnosis of periprosthetic osteolysis should consider the entire spectrum of conditions that can present with radiolucent changes. Thorough review of patient's history and course of symptoms, along with careful evaluation of standard roentgenograms should be always performed and possibly integrated with imaging modalities such as CT, MRI, and bone scintigraphy in order to increase diagnostic accuracy. If uncertainty remains, biopsy should always be considered to rule out malignancy.

Over-expression of receptor activator of nuclear factor-kappaB ligand (RANKL), inflammatory cytokines, and chemokines in periprosthetic osteolysis of loosened total hip arthroplasty

Loosening of total hip arthroplasty (THA) caused by periprosthetic osteolysis induced by ultra-high molecular weight polyethylene (UHMWPE) particles is a major clinical problem. We investigated whether there are differences between loosened THA patients and primary THA patients in (1) receptor activator of nuclear factor-kappaB ligand (RANKL) expression on periprosthetic bone marrow cells; (2) RANKL levels, osteoprotegerin (OPG)/RANKL ratios, the levels of inflammatory cytokines and chemokines in synovial fluid. We used flow cytometric analysis to detect RANKL expression on periprosthetic bone marrow cells. We used enzyme-linked immunoassay and multiplex microsphere-based immunoassay to measure RANKL, OPG, cytokines, and chemokines in synovial fluid. We found loosened THA patients had higher RANKL expression on osteoblastic stromal cells, higher levels of RANKL, interleukin (IL)-6, IL-8, IL-10, interferon-gamma-inducible protein (IP)-10, monocyte chemoattractant protein (MCP)-1, monokine induced by interferon-gamma (MIG), and lower OPG/RANKL ratios in synovial fluid than primary THA patients. There was positive correlation between the levels of IL-6, IL-8, IL-10, IP-10, MCP-1, or MIG and RANKL levels in synovial fluid or RANKL expression on osteoblastic stromal cells. These suggest that UHMWPE particles induce over-expression of RANKL, IL-6, IL-8, IP-10, MCP-1, and MIG in human periprosthetic microenvironment. This results in periprosthetic osteolysis and loosening of THA.

Tenascin‐C levels in pseudosynovial fluid of loose hip prostheses

OBJECTIVE

Aseptic loosening is one of the most important problems that can occur after total hip arthroplasty (THA). In this study, we analysed levels of large tenascin-C (TN-C) variants and compared them in pseudosynovial fluid from patients with aseptic loosening after THA with those in synovial fluid from patients undergoing primary THA (control).

METHODS

Pseudosynovial fluid samples (n = 24) were obtained by aspiration at the time of revision THA performed due to aseptic loosening. Synovial fluid samples (n = 12) were obtained by aspiration at the time of primary THA. Expression of TN-C splice variants was examined using immunoblotting. TN-C levels were measured using an enzyme-linked immunosorbent assay (ELISA) system that we developed previously.

RESULTS

Western blotting showed the presence of large TN-C variants in pseudosynovial fluid of artificial joints with loosening. TN-C levels were approximately three times higher in pseudosynovial fluid of loose artificial joints (median 151.9 ng/mL) than in synovial fluid controls (median 50.1 ng/mL) (p = 0.035).

CONCLUSION

Levels of TN-C including large variant subunits are elevated in pseudosynovial fluid of loose artificial joints, indicating that TN-C is a useful novel biochemical marker of loose hip prostheses.

High levels of substance P and CGRP in pseudosynovial fluid from patients with aseptic loosening of their hip prosthesis

BACKGROUND

Aseptic loosening is the most important complication after total hip arthroplasty (THA). The nervous system has been implicated in the etiology and pathogenesis of joint diseases.

METHODS

We compared levels of substance P (SP) and calcitonin gene-related peptide (CGRP) in pseudosynovial fluid from patients with aseptic loosening after THA with those in synovial fluid from patients undergoing primary THA for osteoarthritis, who served as controls. Levels of SP and CGRP were measured using an enzyme immunoassay.

RESULTS

We found that SP and CGRP levels were significantly higher in the pseudosynovial fluid of loose artificial joints than in the synovial fluid of controls.

INTERPRETATION

SP and CGRP may have a role in aseptic loosening.

Effects of synovial fluid from aseptic prosthesis loosening on collagen production in osteoblasts

Synovial fluid from a loose prosthesis may act as a vehicle for factors that regulate bone turnover. The effect of such synovial fluid on osteoblasts has been studied. Synovial fluid obtained from patients who underwent revision hip arthroplasty because of aseptic prosthesis loosening was studied regarding the effect on protein synthesis, procollagen I mRNA expression, the secretion of procollagen I carboxyterminal propeptide (PICP) and osteocalcin in MG63 osteoblasts. Protein synthesis was increased and procollagen I mRNA expression was decreased by synovial fluid from patients with prosthesis loosening. Synovial fluid stimulated the total PICP in cell medium, but there was no change after correction for cell protein content in the cells. Synovial fluid in patients with prosthesis loosening has a general stimulatory effect on collagen formation and osteoblast proliferation because of a stimulatory effect on cell growth. Aseptic prosthesis loosening may be associated with an increase in bone formation.

Inflammatory response in 85 patients with loosened hip prostheses: a prospective study comparing inflammatory markers in patients with aseptic and septic prosthetic loosening

BACKGROUND

The most common complications of prosthetic hip joints are aseptic mechanical failure and infection. Delayed low-grade infections are seen most often, and they are also most difficult to distinguish from aseptic mechanical failures.

METHODS

We conducted a prospective study to compare inflammatory markers in patients diagnosed with aseptic or septic prosthetic loosening. The diagnostic criteria were based on the decisions of experienced orthopedic surgeons and microbiological analysis of periprosthetic tissue samples taken perioperatively.

RESULTS

Coagulase-negative staphylococci were the commonest pathogens in the infected patients. Pre- or perioperative elevation of C-reactive protein and erythrocyte sedimentation rate were significantly greater in the infection group, as were white blood cell count and levels of cytokines in synovial fluid. The patterns of infiltration of inflammatory cells in periprosthetic tissue were also significantly different between the groups.

INTERPRETATION

A combination of clinical judgment and multiple tissue samples constitutes a good platform for distinguishing between septic and aseptic loosening of prostheses. Moreover, the combined use of several laboratory and histopathological markers of inflammation, especially infiltration of polymorphonuclear cells, further helps the diagnosis.

Effects on osteoclast and osteoblast activities in cultured mouse calvarial bones by synovial fluids from patients with a loose joint prosthesis and from osteoarthritis patients

Aseptic loosening of a joint prosthesis is associated with remodelling of bone tissue in the vicinity of the prosthesis. In the present study, we investigated the effects of synovial fluid (SF) from patients with a loose prosthetic component and periprosthetic osteolysis on osteoclast and osteoblast activities in vitro and made comparisons with the effects of SF from patients with osteoarthritis (OA). Bone resorption was assessed by the release of calcium 45 (⁴⁵Ca) from cultured calvariae. The mRNA expression in calvarial bones of molecules known to be involved in osteoclast and osteoblast differentiation was assessed using semi-quantitative reverse transcription-polymerase chain reaction (PCR) and real-time PCR. SFs from patients with a loose joint prosthesis and patients with OA, but not SFs from healthy subjects, significantly enhanced ⁴⁵Ca release, effects associated with increased mRNA expression of calcitonin receptor and tartrate-resistant acid phosphatase. The mRNA expression of receptor activator of nuclear factor-kappa-B ligand (rankl) and osteoprotegerin (opg) was enhanced by SFs from both patient categories. The mRNA expressions of nfat2 (nuclear factor of activated T cells 2) and oscar (osteoclast-associated receptor) were enhanced only by SFs from patients with OA, whereas the mRNA expressions of dap12 (DNAX-activating protein 12) and fcrγ (Fc receptor common gamma subunit) were not affected by either of the two SF types. Bone resorption induced by SFs was inhibited by addition of OPG. Antibodies neutralising interleukin (IL)-1α, IL-1β, soluble IL-6 receptor, IL-17, or tumour necrosis factor-α, when added to individual SFs, only occasionally decreased the bone-resorbing activity. The mRNA expression of alkaline phosphatase and osteocalcin was increased by SFs from patients with OA, whereas only osteocalcin mRNA was increased by SFs from patients with a loose prosthesis. Our findings demonstrate the presence of a factor (or factors) stimulating both osteoclast and osteoblast activities in SFs from patients with a loose joint prosthesis and periprosthetic osteolysis as well as in SFs from patients with OA. SF-induced bone resorption was dependent on activation of the RANKL/RANK/OPG pathway. The bone-resorbing activity could not be attributed solely to any of the known pro-inflammatory cytokines, well known to stimulate bone resorption, or to RANKL or prostaglandin E₂ in SFs. The data indicate that SFs from patients with a loose prosthesis or with OA stimulate bone resorption and that SFs from patients with OA are more prone to enhance bone formation.

The cellular and molecular biology of periprosthetic osteolysis

The generation of prosthetic implant wear after total joint arthroplasty is recognized as the major initiating event in development of periprosthetic osteolysis and aseptic loosening, the leading complication of this otherwise successful surgical procedure. We review current concepts of how wear debris causes osteolysis, and report ideas for prevention and treatment. Wear debris primarily targets macrophages and osteoclast precursor cells, although osteoblasts, fibroblasts, and lymphocytes also may be involved. Molecular responses include activation of MAP kinase pathways, transcription factors (including NFkappaB), and suppressors of cytokine signaling. This results in up-regulation of proinflammatory signaling and inhibition of the protective actions of antiosteoclastogenic cytokines such as interferon gamma. Strategies to reduce osteolysis by choosing bearing surface materials with reduced wear properties should be balanced by awareness that reducing particle size may increase biologic activity. There are no approved treatments for osteolysis despite the promise of therapeutic agents against proinflammatory mediators (such as tumor necrosis factor) and osteoclasts (bisphosphonates and molecules blocking receptor activator of NFkappaB ligand [RANKL] signaling) shown in animal models. Considerable efforts are underway to develop such therapies, to identify novel targets for therapeutic intervention, and to develop effective outcome measures.

Preliminary dielectric studies of knee swelling fluid in the case of arthritis, which is hard to diagnose

This study addresses the problems connected with knee joint inflammatory swelling diagnosis, especially cases which have difficulty meeting rheumatic and laboratory criteria. A percentage of patients were considered who met the clinical criteria of the Association of Rheumatoid Arthritis (ARA), proceeded without any deviations within the range of rheumatoid factor (RF) laboratory results, and where only serum non-specific immuno-complexes (CIC) increased. The decision to execute a more effective treatment variant (salazopirin, for example, instead of NSAID), required criterial reliability in practice. The purpose of the study was to attempt to find physiochemical distinguishing features in the exudative liquid taken from the knee joints of two groups of patients: group A meeting the clinical criteria of immunological inflammation and a negative rheumatoid factor, and group B with other inflammation concerned with degenerative changes and with negative rheumatoid factor tests. The main area of interest was the question of whether dielectric scanning enables the distinction between immunology and degenerative inflammatory liquid. Analyses of dielectric joint liquid parameters in the domains of frequency and temperature made it possible to observe recurring changes in the shapes of diagrams in the event of the existence of immunological complexes in the studied environment. We found that (1) dielectric scanning diagrams after joint liquid analyses showed similar negative dielectric parameters in group A (inflammatory), B (degenerative) and C (post-accident) with scanning frequencies of about 10,000,000-3501,300 Hz and similar positive parameters of about 3501,300-1593,700 Hz, but qualitative difference dielectric parameters in group A with a frequency of 1593,700-1225,900 Hz, probably dependent on the inflammatory gamma-globulin concentration; (2) higher dielectric parameters (groups B, C) at a scanning frequency of 94,300-57,600 Hz probably dependent on ion concentration; (3) parametric changes of frequency scanning differentiating the diagrams between groups A and B, C, defining the outline pilot study recommended ranges of frequency and temperature testing for further investigations.

Malignant tumors at the site of total hip prosthesis. Analytic review of 46 cases

During the years 1974 to 2003, a total of 46 cases of malignant tumors at the site of total hip arthroplasty, 41 sarcomas, 4 lymphomas, and 1 epidermoid carcinoma, have been reported in the Western literature. Soft tissue sarcomas occurred in 31 and bone sarcomas in 10 cases. Malignant fibrous histiocytoma was the most common in 20 (65%) of all soft tissue sarcomas. The patients with malignant tumors had been operated on more often for secondary osteoarthritis and had more local complications than those in ordinary total hip arthroplasty series. Primary osteoarthritis was the indication in 63% and secondary osteoarthritis in 37% of the 38 reported cases. Tumor developed after 8 (17%) revisions. Deep infection complicated 4 (9%) of the cases. Four cases (9%) were preceded by a precondition for cancer, 2 postradiation necroses of the femoral head, 1 chronic sinus, and 1 Mafucci syndrome. Mean age of the patients at the time of first implantation was 59 years (range, 24-79 years). The mean latent period was 6 years (range, 0.5-20 years) from the first operation. Longer latency period did not correlate positively with the cancer risk. Sarcomas were highly aggressive. Of the 31 reported patients, 24 (77%) died within 1 year after the diagnosis. The number of reported sarcoma cases is low considering the total population behind the cases. In addition, one observed local sarcoma from Nordic cohorts was less than expected. Chronic, particle-induced inflammation around the prosthesis does not seem to increase the risk for carcinogenesis.

Serum interleukin 8 levels correlate with synovial fluid levels in patients with aseptic loosening of hip prosthesis

Levels of inflammatory cytokines (tumor necrosis factor alpha, interleukin [IL] 6, and IL-8) in serum from patients with osteolysis on radiographs after hip arthroplasty [osteolysis(+), n = 28], patients without osteolysis after hip arthroplasty [osteolysis(-), n = 24], and nonoperated healthy subjects [controls, n = 20] were determined. In addition, cytokine levels in synovial fluid from patients undergoing revision total hip arthroplasty (n = 14) for loosening were measured and compared with each other and with the area of osteolysis on radiographs. Serum IL-6 and IL-8 levels were significantly higher in the osteolysis(+) group than in the osteolysis(-) or the control groups. Furthermore, a significant correlation was found between the serum and synovial fluid IL-8 levels and between synovial fluid IL-8 levels and the area of osteolysis in patients undergoing revision total hip arthroplasty. Therefore, serum IL-8 levels could be a useful periprosthetic osteolysis marker.

Pseudosynovial fluid from loosened total hip prosthesis induces osteoclast formation

Interface tissue between the bone and loosening total hip implant is acidic and highly osteolytic. It is characterized by the formation of cathepsin K positive foreign body giant cells. Similar structures to those found in the normal joint surround the artificial hip joint. Cells in synovial membrane of the artificial hip generate synovial fluid that is called pseudosynovial fluid. Interface tissue fibroblasts are able to produce receptor activator of NF-kappaB ligand (RANKL), which can induce osteoclastogenesis during the loosening process. Western blot analysis indicated that RANKL is present in the pseudosynovial fluid. Pseudosynovial fluid induced cultured peripheral blood mononuclear cells to form multinuclear TRAP positive giant cells. In the presence of osteoprotegerin, the soluble RANKL decoy receptor, the number of TRAP positive multinuclear cells was reduced to half (p < 0.05). The multinuclear cells induced with pseudosynovial fluid contained active cathepsin K protein and were capable of bone matrix resorption in vitro. The cells were shown to express osteoclast phenotype markers, such as mRNA for cathepsin K, TRAP, and calcitonin receptor. It is therefore apparent that pseudosynovial fluid from patients with aseptic loosening of total hip prosthesis contains a potent osteoclastogenic factor RANKL that further suggests a favorable environment for osteoclast formation in the peri-implant tissues. It is thus concluded that suppression of RANKL activity may be beneficial in terms of increasing the lifetime of total hip prostheses.

Acute phase response in patients undergoing lumbar spinal surgery: modulation by perioperative treatment with naproxen and famotidine

In orthopaedic surgery, perioperative administration of non-steroidal anti-inflammatory drugs has been shown to reduce postoperative pain and analgesic consumption. In addition, preoperative administration of ibuprofen has proved to reduce interleukin-6 (IL-6) release, while that of ranitidine reduced postoperative IL-6-induced C-reactive protein synthesis in patients undergoing abdominal surgery. However, it has not been established whether the preoperative administration of both types of drugs may reduced the postoperative inflammatory reaction after instrumented spinal surgery. Accordingly, our objective was to investigate the effects of preoperative treatment with naproxen plus famotidine on the postoperative systemic inflammatory reaction in patients undergoing instrumented lumbar spinal surgery. Forty consecutive patients scheduled for elective instrumented spinal fusion were alternately assigned to receive either naproxen (500 mg/day, p.o.) plus famotidine (40 mg/day, p.o.) for 7 days before operation, or no adjuvant treatment. Haematological parameters, acute phase proteins, complement fractions, immunoglobulins and cytokines were determined 7 days and immediately before surgery, and on days 0, 1, 2 and 7 after surgery. Haematological parameters, clinical data, duration of surgery, blood loss, perioperative blood transfusion and postoperative complications were similar in the two groups, although pretreated patients showed lower increases in body temperature and required less analgesic medication. Compared with preoperative levels, IL-6 levels were significantly increased postoperatively in all patients with no differences between groups. C-reactive protein, alpha(1)-acid-glycoprotein and haptoglobin levels were also significantly increased postoperatively in all patients; however, they were significantly lower in pretreated patients. In conclusion, perioperative treatment with naproxen plus famotidine was well tolerated and reduced the acute phase response after instrumented spinal surgery. However, further research is needed to determine the best dose and timing of preoperative treatment administration, and to correlate these changes with long-term clinical results.

Bone turnover markers and cytokines in joint fluid: analyses in 10 patients with loose hip prosthesis and 39 with coxarthrosis

We analyzed bone turnover markers (osteocalcin, bone ALP, beta-crosslaps-CTX) and cytokines (IL-1, IL-8 and IL-10) in hip joint fluid in 10 patients before revision surgery and in 39 with idiopathic coxarthrosis. Patients with loose implants had lower concentrations of resorption marker than those with arthrosis (0.8 vs 1.3 ng/mL), but bone formation marker osteocalcin was reduced (4.2 vs 22.6 ng/mL). IL-8 and IL-10 levels were elevated in patients with implant failure (870 vs 340 pg/mL; 14.3 vs 4.0 pg/mL). We found a negative correlation between the bone resorption marker (CTX) and IL-10 in cases with prosthesis loosening and a positive correlation between IL-10 and time-to-revision. We conclude that enhanced local production of inflammatory cytokines leading to suppressed bone formation is a part of the loosening process. The expression of anti-inflammatory mediators is not sufficient to counteract the imbalance in bone turnover.

Effect of submicron polyethylene particles on an osseointegrated implant: an experimental study with a rabbit patello-femoral prosthesis

In a rabbit model of a weight bearing, articulating prosthetic joint we repeatedly injected submicron particles of Ultra-High-Molecular-Weight-Polyethylene (UHMWPE) produced in a hip simulator. The contralateral knee with the same prosthesis was injected with carrier (NaCl) without UHMWPE. Histomorphometrical studies on undecalcified cut and ground sections at 26 and 42 weeks involved quantifications of the entire bone to metal contact and the bone area around each implant. We found no statistically significant differences between test and control groups, and the UHMWPE debris did not induce any significant osteolysis, indicating that an osseointegrated implant with a sealed interface may not be affected by UHMWPE debris or progress to aseptic loosening.

Pro-inflammatory and anti-inflammatory cytokine increases after spinal instrumentation surgery

We investigated the effects of instrumentation on postoperative inflammatory reaction and identified standard changes in serum cytokine concentrations after spinal surgery. Pro-inflammatory cytokines [interleukin (IL)-6 and IL-8] and anti-inflammatory cytokines [IL-10, IL-1 receptor antagonist (ra), and soluble tumor necrosis factor receptors (sTNF-R) I and II] were assayed in serum from seven patients with lumbar spinal posterior decompression, six with spinal decompression and posterolateral fusion without instrumentation and seven with spinal decompression and posterolateral fusion with instrumentation. All cytokines after spinal instrumentation increased significantly more than in other groups on postoperative days 0 and 1. Seven days after SI, IL-6, -8, and -10 had normalized, but IL-1ra and sTNF-RI and sTNF-RII remained elevated. Both pro-inflammatory and anti-inflammatory cytokines were enhanced by implants in the acute phase, whereas only anti-inflammatory cytokines were enhanced by instruments in the subacute phase.

Correlation of synovial fluid cytokine levels with histological and clinical parameters of primary and revision total hip and total knee replacements

We retrieved synovial tissue and fluid samples from patients undergoing primary total hip replacement (THR) (n 15), revision of aseptically loose THR (n 12), primary total knee replacement (TKR) (n 13) and revision of aseptically loose TKR (n 6). Several histological parameters were assessed on a relative scale of 14. Primary TJRs were clinically evaluated for degree of osteoarthrosis. Revision TJRs were assessed for migration of the implant, gross loosening and the degree of radiolucency. Cytokine levels in synovial fluid were determined with ELISA. All cytokines were significantly higher in revision TJRs than in primary replacements, as were the degree of macrophage and giant cell infiltration. We found no relationship between any clinical variable and the levels of any cytokine, but migration of the implant was related to the presence of PE debris. A significant correlation was seen between the presence of macrophages and the levels of IL-1beta, IL-8 and IL-10, but not IL-6. No differences were noted between hips and knees for any of the variables, except in the levels of IL-6, where higher levels were found in THRs. These results suggest a unique role for IL-6 that requires further investigation.

Early-phase enhanced inflammatory reaction after spinal instrumentation surgery

STUDY DESIGN

The erythrocyte sedimentation rate, C-reactive protein, white blood cell count, and body temperature were measured prospectively in patients after two types of spinal surgery without complications and three cases of infection after spinal instrumentation surgery.

OBJECTIVES

To investigate the effects of instrumentation on postoperative inflammatory reaction, and to describe early detection of postoperative wound infection.

SUMMARY OF BACKGROUND DATA

In thoracic and abdominal surgery as well as hip arthroplasty, C-reactive protein has proved more valuable than erythrocyte sedimentation rate for early detection of postoperative infectious complications. It has not yet been established, however, how inflammatory parameters change after surgery when spinal instruments have been inserted into the body.

METHODS

For this study, two groups of patients were examined: a control group that underwent spinal decompression surgery without instrumentation (n = 36) and another group that underwent spinal decompression and fusion surgery with spinal instrumentation (n = 37). The erythrocyte sedimentation rate, C-reactive protein, white blood cell count, and body temperature were recorded 1 day before surgery and on days 0 to 4, 7, 11, 14, 21, 28, and 42 after surgery.

RESULTS

Inflammatory indexes (i.e., C-reactive protein, erythrocyte sedimentation rate, white blood cell count, and body temperature) were significantly higher for the surgery with instrumentation than for the spinal decompression surgery without instrumentation. Multiple regression analysis showed that C-reactive protein and erythrocyte sedimentation rate peaks significantly correlated with the use of instrumentation (C-reactive protein: P = 0.000257, erythrocyte sedimentation rate: P = 0.000132). In the patients with infection after spinal instrumentation surgery, C-reactive protein, white blood cell count, and body temperature started to increase again 4 to 11 days after surgery. The elevation of erythrocyte sedimentation rate levels was prolonged.

CONCLUSIONS

Erythrocyte sedimentation rate and C-reactive protein display a significantly higher reaction after spinal surgery with instrumentation. Renewed elevation of C-reactive protein, white blood cell count, and body temperature after postoperative days 4 to 7 may be a critical sign of postoperative infection.

Sealing effect of hydroxyapatite coating: a 12-month study in canines

This study addresses the clinical problems regarding access of wear debris to the bone-implant interface and the possible dissemination of polyethylene (PE) particles to distant organs. We inserted two implants into each knee of 7 dogs allowing access of joint fluid to the bone-implant interface with a 0.75 mm initial gap around the implant. Hydroxyapatite (HA)-coated and non-coated (Ti) titanium alloy implants were randomly allocated to each distal femoral condyle. PE particles were repeatedly injected into the right knee joint 3 weeks after surgery for a period of 49 weeks, while only vehicle was injected into the left knee joint. We found huge amounts of PE particles mainly in the bone-implant interface around Ti implants. Infiltration of mononuclear inflammatory cells was present around 3 of 7 Ti implants in relation to PE particles. HA implants had approximately 70% bone ongrowth. In contrast, no bone ongrowth was seen on any Ti implants, all being surrounded by a fibrous membrane. The number of PE particles was evaluated semi-quantitatively. More PE particles were found around Ti implants than with HA implants (p < 0.002). Specimens from iliac lymph nodes, liver, spleen and lung were examined and showed dissemination of PE particles only in regional lymph nodes.

Cemented first-time revisions of the femoral component: prospective 7 to 13 years' follow-up using second-generation and third-generation technique

In a prospective, consecutive study of first-time cemented femoral revisions, 109 hips were evaluated for a minimum of 7 years. There were 87 Charnley (18 standard, 69 long), 21 Spectron (3 standard, 18 long), and 1 Brunswick long-stem arthroplasties. There was an increased risk for rerevision in younger patients (P = .0001) and with use of standard stems (P = .002). Factors of importance for development of mechanical failure were younger age (P = .0001), presence of more pronounced bone defects (P < .005), use of standard stems (P < .0005), and presence of radiolucencies on the postoperative radiographs (Gruen zones 4 and 6) (P < .01). Our results confirm that cemented femoral revisions are a durable option in elderly patients, when improved cementing techniques and long-stem prostheses are used.