Objectives. The purpose of this study was to examine the bactericidal efficacy of hydrogen peroxide (H. 2. O. 2. ) on Cutibacterium acnes (C. acnes). We hypothesize that H. 2. O. 2. reduces the bacterial burden of C. acnes. Methods. The effect of H. 2. O. 2. was assessed by testing bactericidal effect, time course analysis, growth inhibition, and minimum bactericidal concentration. To assess the bactericidal effect, bacteria were treated for 30 minutes with 0%, 1%, 3%, 4%, 6%, 8%, or 10% H. 2. O. 2. in saline or water and compared with 3% topical H. 2. O. 2. solution. For time course analysis, bacteria were treated with water or saline (controls), 3% H. 2. O. 2. in water, 3% H. 2. O. 2. in saline, or 3% topical solution for 5, 10, 15, 20, and 30 minutes. Results were analyzed with a two-way analysis of variance (ANOVA) (p < 0.05). Results. Minimum inhibitory concentration of H. 2. O. 2. after 30 minutes is 1% for H. 2. O. 2. prepared in saline and water. The 3% topical solution was as effective when compared with the 1% H. 2. O. 2. prepared in saline or water. The controls of both saline and water showed no reduction of bacteria. After five minutes of exposure, all mixtures of H. 2. O. 2. reduced the percentage of live bacteria, with the topical solution being most effective (p < 0.0001). Maximum growth inhibition was achieved with topical 3% H. 2. O. 2. . Conclusion. The inexpensive and commercially available topical solution of 3% H. 2. O. 2. demonstrated superior bactericidal effect as observed in the minimum bactericidal inhibitory concentration, time course, and colony-forming unit (CFU) inhibition assays. These results support the use of topical 3% H. 2. O. 2. for five minutes before surgical skin preparation prior to shoulder surgery to achieve eradication of C. acnes for the skin. Cite this article: P. Hernandez, B. Sager, A. Fa, T. Liang, C. Lozano, M. Khazzam. Bactericidal efficacy of hydrogen peroxide on Cutibacterium acnes. Bone Joint Res 2019;8:3–10. DOI: 10.1302/2046-3758.81.BJR-2018-0145.R1

Polymethylmethacrylate (PMMA) Acrylic Bone Cement is a polymer used to anchor the prosthesis during Joint Replacement Surgery. Arthroplasty with Bone Cement is associated with late loosening, compromising prosthetic stability leading to Revision arthroplasty. Different irrigating solutions such as Hydrogen Peroxide or Saline are used during arthroplasty. The aim of the study was to analyse the effects of Hydrogen Peroxide on the mechanical properties of Bone Cement. Materials and Methods: Cement was mixed as per standard methods used in theatre, in a vacuum and at a temp of 18 degrees centigrade. Once the cement was mixed it was then placed in conical moulds and the exposed surface was either exposed to saline or Hydrogen Peroxide solution (6% from a standard theatre preparation). We studied the effect of Hydrogen Peroxide on Dough time, Curing time, Surface Analysis and Hardness of PMMA. Dough time was performed with latex examination gloves. Curing time was measured at 15 seconds intervals using a Vickers hardness transistor. Cement hardness was assessed using the same machine. Surface analysis was performed by preparing the samples using a grit rotaforce machine. Palacos Bone Cement was used and tests were conducted according to ASTM F-451 and ISO 5833 standards. Results: The samples exposed to hydrogen peroxide showed an increase in the dough time in comparison to the controls from 3.5 minutes to 5 minutes. Curing time showed a difference of 13.5 minutes for the controls as opposed to 17 minutes for the HP contaminated samples. Surface hardness reduced from a mean of 17.5hv to 14.3hv after exposure to hydrogen peroxide (p< 0.05). There was increased staining of the Hydrogen Peroxide sample, with surface irregularities, and an associated increase in surface porosity. Surface porosity increased from 120um (SD 11.2) to 180um (SD 8.7) (p< 0.05). Conclusion: We have shown that the use of hydrogen peroxide contamination of bone cement interferes with the biomechanical properties of the cement, leading to an overall reduction in strength and hardness of the cement. This may lead to an associated reduction in the strength of the bone cement interface and precipitate early micro-motion and loosening of the prosthesis

There are several different ways of preparing the femoral canal prior to cementing a hip prosthesis. This study investigated the mechanical strength of the cement-bone interface of four different types of preparation determined by the maximum tensile force required to separate a cemented prosthesis from its cancellous bone origin.

Forty-eight fresh-frozen ox femora were prepared for hip arthroplasty, In a four-way comparison, groups of eleven femora were prepared by irrigation using

syringe injected normal saline;

Specimens were secured to a Material-test System (MTS), and the femoral implant pulled from the femur uni-axially at a rate of 5mm/min. The ‘pull-out strength’ was defined as the maximum tension recorded by the MTS during separation. Cement interdigitation was also inspected for each technique by microscopy of eight bone-implant transverse sections taken from prepared specimens.

Following an analysis of variance and pair-wise Fisher comparison, the average pull-out strength of the cemented prosthesis was significantly higher (P< 0.001) using pulse-lavage brushing (mean 8049.2 N), and pulse-lavage brushing in combination with hydrogen-peroxide soaked gauze (mean 8489.1 N), than with normal saline irrigation (mean 947.1 N) or hydrogen-peroxide soaked gauze preparation (mean 1832.6 N). Prosthesis pull-out strength following pulse-lavage brushing in combination with hydrogen-peroxide soaked gauze was not significantly different (P> 0.05) than preparing with pulse-lavage brushing alone. Low and high power microscopy of specimen transverse sections revealed the greatest levels of cement penetration in specimens prepared using pulse-lavage brushing.

This study demonstrated that one of the most effective preparations of the femoral canal for optimal mechanical fixation between cement and cancellous bone is pulse- lavage brushing. The use of hydrogen-peroxide soaked gauze in femoral canal preparation, either alone or in combination with pulse-lavage brushing, may not significantly improve prosthesis fixation.

Aims. This study was performed to explore the effect of melatonin on pyroptosis in nucleus pulposus cells (NPCs) and the underlying mechanism of that effect. Methods. This experiment included three patients diagnosed with lumbar disc herniation who failed conservative treatment. Nucleus pulposus tissue was isolated from these patients when they underwent surgical intervention, and primary NPCs were isolated and cultured. Western blotting, reverse transcription polymerase chain reaction, fluorescence staining, and other methods were used to detect changes in related signalling pathways and the ability of cells to resist pyroptosis. Results. Western blot analysis confirmed the expression of cleaved CASP-1 and melatonin receptor (MT-1A-R) in NPCs. The cultured NPCs were identified by detecting the expression of CD24, collagen type II, and aggrecan. After treatment with hydrogen peroxide, the pyroptosis-related proteins NLR family pyrin domain containing 3 (NLRP3), cleaved CASP-1, N-terminal fragment of gasdermin D (GSDMD-N), interleukin (IL)-18, and IL-1β in NPCs were upregulated, and the number of propidium iodide (PI)-positive cells was also increased, which was able to be alleviated by pretreatment with melatonin. The protective effect of melatonin on pyroptosis was blunted by both the melatonin receptor antagonist luzindole and the nuclear factor erythroid 2–related factor 2 (Nrf2) inhibitor ML385. In addition, the expression of the transcription factor Nrf2 was up- or downregulated when the melatonin receptor was activated or blocked by melatonin or luzindole, respectively. Conclusion. Melatonin protects NPCs against reactive oxygen species-induced pyroptosis by upregulating the transcription factor Nrf2 via melatonin receptors. Cite this article: Bone Joint Res 2023;12(3):202–211

Introduction: One of the most common complications following total joint surgery is aseptic loosening. Improving the bone-cement interlock may increase implant longevity. An ideally prepared bony surface is dry; clean; free from marrow, fat and debris; free from active bleeding; and free from micro-organisms. Lavage removes debris, blood and fat from the interstices of the bone surface so as to allow optimal penetration of the cement. The hypothesis that we investigated in this study was that lavage with a detergent solution obtains a greater depth of cement penetration into bone compared with lavage using 0.9% saline, hydrogen peroxide or an alcohol solution. Methods: The cancellous bone of ovine femoral condyles were cut into 10×10×13mm blocks. Lavage solutions were delivered via a pulsatile system and directed towards one side of the bone block. All blocks were swabbed dry. A high viscosity cement was manually mixed and applied to the sandblasted surface of titanium alloy plate (10×10mm, weight 0.9g ±0.01g). The titanium plate and cement were placed on the irrigated bone block, and a known weight applied to achieve pressurisation. Time, temperature and method were controlled. The prosthesis-cement-bone composite was sectioned perpendicularly, and image analysis used to quantify penetration depths. 10 readings were recorded per block with 6 blocks per lavage group. Results: Cancellous bone porosity averaged 75.2% (±4.0) . The mean penetration depth in the saline group averaged 3.39mm (± 0.77); 3.04mm (± 0.59) using a 2% alcohol solution; 3.33mm (±0.79) using a 3% hydrogen peroxide solution; and 5.41mm (± 1.30) when using the detergent lavage. There was no significant difference in cement penetration depth between hydrogen peroxide and saline irrigation (p> 0.05), nor with hydrogen peroxide and alcohol irrigation (p> 0.05). Irrigation with saline however, afforded statistically superior cement penetration than that of alcohol lavage (p < 0.012). Irrigation with detergent solution demonstrated significantly greater depth of penetration than all three other lavage groups (saline p< 0.05; alcohol p< 0.05; hydrogen peroxide p< 0.05). Discussion: Detergents can physically remove particulate matter and emulsify and remove fats, thereby acting to maximise porosity of the cancellous bone network and optimise space for occupation by intruding cement. This study has proven the ability of a detergent solution to provide a clean, debris free cancellous network, which consequently provides a significantly greater depth of cement penetration than other commonly used irrigating agents. It was noted that cement penetration into cancellous bone followed the line and depth of cleaning from lavage. In conclusion, the hypothesis can be accepted, and lavage with a detergent solution affords a statistically greater depth of cement penetration into bone than that of the universally used 0.9% saline lavage

Cells of the intervertebral disc exist in an unusual environment compared to those of other tissues. Within the disc there are low levels of nutrients available, low oxygen levels and it is an acidic environment due to high lactate levels. Apoptosis (programmed or controlled cell death) has been reported in intervertebral discs, as well as necrosis (uncontrolled cell death). This study has focused on examining the sensitivity of nucleus pulpo-sus (NP) cells to several stimuli, in comparison to two other cells types. Ultra violet (UV) irradiation, serum starvation (with no foetal calf serum) and treatment with 2mM hydrogen peroxide were used to induce apoptosis in cultured bovine NP cells, HeLa (cancer cell line) and 293T cells (human embryo kidney derived) cells. Apoptosis was identified by nuclear morphology following staining with fluorescent Hoechst 33342 dye and propidium iodide; the incidence was measured at 24, 48 and 72 hours. Untreated controls were used for each treatment and at each time point. The incidence of apoptosis increased with time for all treatments. After 72 hours, UV treatment produced the highest levels of apoptosis with levels of apoptosis occurring in the order of HeLa (94%) > NP cells (29%) > 293T cells (15%). Treatment with hydrogen peroxide and serum starvation induced apoptosis at lower levels in all three cell types (maximum of 30%). Serum starvation induced apoptosis in only 10% of NP cells at 72 hours, compared to 20% in HeLa cells. None of the controls contained apoptotic cells. NP cells are stimulated to apoptose in response to UV irradiation, hydrogen peroxide and serum starvation. However, levels of apoptosis are much lower after UV treatment in comparison to HeLa cells (3 times lower), suggesting that they may have a protective mechanism to this apoptotic stimulus, compared to HeLa cells. The low levels of apoptosis observed in NP cells with serum starvation may be due to the low nutrient environment that they exist in normally

Introduction Bone morphogenetic protein-7 (BMP-7) is known to stimulate both cellular proliferation and extracellular matrix synthesis in the intervertebral disc but its protective role in apoptosis is unknown. The aim of this study was to determine whether BMP-7 protect cultured intervertebral disc cells following stimulation of apoptosis. Methods Nucleus pulposus tissues were obtained from consent individuals under surgical procedures and digested with collagenase prior to culturing. Cellular apoptosis was achieved by either tumor necrosis factor-alpha (TNF-β) or hydrogen peroxide (H2O2) incubation. BMP-7 (Stryker) was used at 100ng/ml, 5 hours prior to the addition of apoptotic stimulation. Cellular apoptosis was detected by TUNEL assay, caspase-3 activity and caspase-3 protein expression. Cellular proliferation and viability was assayed by H3-thymidine incorporation and MTS assay respectively. Collagen II and aggrecan protein levels were measured using western blots and immunostaining. Proteoglycan synthesis was determined by (35)S-sulfate incorporation method. Nitric oxide and alkaline phosphatase activity were measured. Results Both extrinsic and intrinsic apoptotic pathways were induced by TNF-β or hydrogen peroxide with increased proteolytic activity of caspase-3 as well as cellular shrinkage and nuclear condensation. Addition of BMP-7 prior to stimulation of apoptosis resulted in complete block of the apoptotic effects of both inducers as well as the cellular nitric oxide induced by TNF-β and BMP-7 increases cellular viability, proliferation and extracellular matrix production in an apoptotic environment with no osteoblastic activity induction of discal cells. Discussion BMP-7 prevents apoptosis of cultured human disc cells induced by either tumor necrosis factor-alpha (TNF-β) or hydrogen peroxide. Induction of apoptosis led to down regulation of extracellular matrix proteins, decreased cell viability, morphological changes and activation of caspase-3, however addition of BMP-7 alone prevented the effects observed. One possible mechanism of the anti-apoptotic effects of BMP-7 was shown by its retardation of the elevated levels of TNF-β induced nitric oxide

Leucocytes are white blood cells that help the body fight against bacteria, viruses and tumour cells. However, the activity of leucocytes has been implicated in other clinically important inflammatory conditions such as ischaemic heart disease, stroke, and during cardio-aortic and orthopaedic surgery. The main objectives of this study was to optimise methods for the isolation of leucocyte subpopulations (neutrophils and monocytes), and to assess in vitro the effects of PMA and fMLP on markers of leucocyte adhesion (CD11b, CD62L) and activation (intracellular hydrogen peroxide) (n=10). Leucocyte subpopulations were labelled by incubation with fluorescein isothiocya-nate (FITC) conjugated anti-human CD11b and CD62L antibodies. The cell surface expression of these labelled adhesion molecules were measured by flow cytometry. Intracellular production of hydrogen peroxide by neutrophils and monocytes was measured by flow cytometry, using the fluorochrome dichloroflurorescin diacetate (DCFH-DA). These were visualised by Immunofluorescence microscopy. During this study, methods of isolating leucocyte subpopulations from whole blood were optimised. This ensured that these cells were isolated with consistently high yields, purity and with no changes in cellular function. Following incubation with PMA and fMLP, neutrophils and monocytes displayed an increase in CD11b cell surface expression; a decrease in CD62L cell surface expression; and increased leucocyte activation. Leucocyte activation was represented by the intracellular production of hydrogen peroxide. In conclusion this study confirms that both PMA and fMLP have an intrinsic effect on markers of leucocyte function. These findings are in agreement with previous studies performed

Aim. Polypropylene (PPE) synthetic mesh is increasingly used in knee arthroplasty surgery to salvage a disrupted extensor mechanism. Despite its clinical success, it is associated with a high rate of periprosthetic joint infection (PJI), which is hypothesized to be caused by bacterial biofilm. The purpose of the current study is to describe the progression of PPE-based biofilm formation over time and to determine if intraoperative antiseptic solutions could be used to effectively remove biofilm when treating PJI. Method. Commercially available knotted monofilament PPE mesh. 1. was cut into 10mm circular shape, immersed in tryptic soy broth (TSB) with methicillin-sensitive staphylococcus aureus and cultured individually in 48-well plates for 10 days to elucidate the biofilm grown on mesh over time. At every 24 hours, a triplicate of samples was retrieved and biofilm on the mesh was dislodged by sonicating at 52 kHz for 15 minutes and quantified by counting colony-forming units (CFUs) after overnight growth. The biofilm growth was also verified using scanning electron microscopy. The effect of saline and antiseptic solutions was verified by exposing 1) 0.05% chlorohexidine gluconate. 2. , 2) acetic acid-based mixture. 3. , 3) diluted povidone-iodine (0.35%), 4) undiluted povidone-iodine (10%). 4. , and 5) 1:1 combination of 10% povidone-iodine & 3% hydrogen peroxide on immature and mature biofilms for 3 minutes, created by culturing with bacteria for 24 hours and 72 hours respectively. All experiments were performed in quintuples and repeated. Antiseptic treatments that produced a three-log reduction in CFU counts compared to controls were considered clinically significant. Results. PPE-mesh produced reliable CFU counts at 24 hours and reached peak growth at 72 hours. For immature biofilm, all formulations of povidone-iodine produced significant reductions in CFU counts compared to controls. Although not meeting the established threshold, saline irrigation removed 86.5% of CFUs, while formulation based on chlorohexidine and acetic acid removed 99.2% and 99.7% respectively. For mature biofilm, formulations based on povidone-iodine and acetic acid produced significant reductions in CFU counts. Conclusions. Our findings suggest biofilm may form on mesh as early as 24 hours after bacterial exposure. Povidone-iodine formulations were consistently the most effective in removing biofilm on mesh surfaces. We recommend that surgeons consider using an antiseptic solution, preferably povidone-iodine-based, in addition to regular saline lavage when attempting to salvage a PPE mesh in the setting of PJI. 1. Marlex mesh (CR Bard, Davol Inc, Warwick, RI), . 2. Irrisept (Irrimax Corp, Gainesville, FL), . 3. Bactisure (Zimmer-Biomet, Warsaw, IN), . 4. Aplicare (Inc, Meriden, CT)

Objectives. Oxidative stress plays a major role in the onset and progression of involutional osteoporosis. However, classical antioxidants fail to restore osteoblast function. Interestingly, the bone anabolism of parathyroid hormone (PTH) has been shown to be associated with its ability to counteract oxidative stress in osteoblasts. The PTH counterpart in bone, which is the PTH-related protein (PTHrP), displays osteogenic actions through both its N-terminal PTH-like region and the C-terminal domain. Methods. We examined and compared the antioxidant capacity of PTHrP (1-37) with the C-terminal PTHrP domain comprising the 107-111 epitope (osteostatin) in both murine osteoblastic MC3T3-E1 cells and primary human osteoblastic cells. Results. We showed that both N- and C-terminal PTHrP peptides at 100 nM decreased reactive oxygen species production and forkhead box protein O activation following hydrogen peroxide (H. 2. O. 2. )-induced oxidation, which was related to decreased lipid oxidative damage and caspase-3 activation in these cells. This was associated with their ability to restore the deleterious effects of H. 2. O. 2. on cell growth and alkaline phosphatase activity, as well as on the expression of various osteoblast differentiation genes. The addition of Rp-cyclic 3′,5′-hydrogen phosphorothioate adenosine triethylammonium salt (a cyclic 3',5'-adenosine monophosphate antagonist) and calphostin C (a protein kinase C inhibitor), or a PTH type 1 receptor antagonist, abrogated the effects of N-terminal PTHrP, whereas protein phosphatase 1 (an Src kinase activity inhibitor), SU1498 (a vascular endothelial growth factor receptor 2 inhibitor), or an anti osteostatin antiserum, inhibited the effects of C-terminal PTHrP. Conclusion. These findings indicate that the antioxidant properties of PTHrP act through its N- and C-terminal domains and provide novel insights into the osteogenic action of PTHrP. Cite this article: S. Portal-Núñez, J. A. Ardura, D. Lozano, I. Martínez de Toda, M. De la Fuente, G. Herrero-Beaumont, R. Largo, P. Esbrit. Parathyroid hormone-related protein exhibits antioxidant features in osteoblastic cells through its N-terminal and osteostatin domains. Bone Joint Res 2018;7:58–68. DOI: 10.1302/2046-3758.71.BJR-2016-0242.R2

Summary Statement. The problem facing this research is to promote rapid osteointegration of titanium implants and to minimise the risks of infections by the functionalization with different agents, each designed for a specific action. A patented process gives a multifunctional titanium surface. Introduction. A patented process of surface modification is described. It gives a multifunctional surface with a multiscale roughness (micro and nano topography), that is excellent for osteoblast adhesion and differentiation. It has a high degree of hydroxylation, that is relevant for inorganic bioactivity (apatite-HA precipitation) and it is ready for a functionalization with biological factors. A direct grafting of ALP has been obtained. Moreover, the growth of an antibacterial agent within the surface oxide layer can be useful in order to combine the osteoinduction ability to antimicrobial effects. The selection of an inorganic agent (metal nanoparticles) has the advantage to avoid an eventual development of antibiotic resistance by bacteria. Experimental Methods. Ti-cp and Ti6Al4V samples were polished or blasted, etched in diluted hydrofluoric acid (step 1a), oxidised in hydrogen peroxide (step 1b), incubated in Tresyl chloride (step 2a) and Alkaline phosphatase (ALP) enzyme (step 2b) [1, 2]. A water solution, containing a salt of the metal to be added to the surface as an inorganic antibacterial agent, can be introduced during the oxidation in hydrogen peroxide. Surface morphology and chemical composition were investigated by Scanning Electron Microscopy (SEM) and Field Emission Scanning Electron Microscopy (FESEM) equipped with Energy Dispersive Spectroscopy (EDS). The composition of the outermost surface layer and the chemical state of elements were analyzed by X-Ray Photoelectron Spectroscopy (XPS). The activity of grafted enzyme was studied by an enzymatic activity test. In vitro bioactivity was evaluated by soaking the samples in simulated body fluid and SEM observation to verify hydroxyapatite (HA) precipitation. Antibacterial activity has been determined by inhibition halo test against S aureus. Results and Discussion. A peculiar multi-scale topography, with spongy-like nanometric features, was obtained after the inorganic treatment (step 1a-1b). This morphology can be superimposed on the micro-or macro roughness deriving from acid etching or blasting, by properly optimizing the process parameters. Moreover, the treated surfaces present a high density of hydroxyl groups (XPS data) and they are bioactive (HA precipitation after soaking in SBF for 15 days). Metal (Ag, Cu, Zn) nanoparticles can be grown within the surface oxide layer and they are effective as antimicrobial inorganic agents. The amount of the metal nanoparticles can be tailored in order to have an antibacterial or a bacteriostatic surface. The effective grafting of ALP (step 2a-2b) has been shown by XPS because of the appearance of characteristic peaks in the carbon region. Moreover, it has been observed that ALP maintains its activity after grafting by an enzymatic activity test. ALP grafting improves HA precipitation kinetics. Conclusions. An innovative process was applied to titanium surfaces in order to obtain a better bone integration ability and antibacterial activity. A multi scale surface topography (micro and nano features) was successfully obtained together with an high hydroxylation degree. Modified surfaces are able to induce hydroxyapatite precipitation in vitro and to graft ALP, maintaining its activity and improving bioactivity. Metal nanoparticles embedded in the surface oxide layer have an antibacterial effect

The number of cemented femoral stems implanted in the United States continues to slowly decrease over time. Approximately 10% of all femoral components implanted today are cemented, and the majority are in patients undergoing hip arthroplasty for femoral neck fractures. The European experience is quite different. In the UK, cemented femoral stems account for approximately 50% of all implants, while in the Swedish registry, cemented stems still account for the majority of implanted femoral components. Recent data demonstrating some limitations of uncemented fixation in the elderly for primary THA, may suggest that a cemented femoral component may be an attractive alternative in such a group. Two general philosophies exist with regards to the cemented femoral stem: Taper slip and Composite Beam. There are flagship implants representing both philosophies and select designs have shown excellent results past 30 years. A good femoral component design and cementing technique, however, is crucial for long-term clinical success. The author's personal preference is that of a “taper slip” design. The cemented Exeter stem has shown excellent results past 30 years with rare cases of loosening. The characteristic behavior of such a stem is to allow slight subsidence of the stem within the cement mantle through the process of cement creep. One or two millimeters of subsidence in the long-term have been observed with no detrimental clinical consequences. There have been ample results in the literature showing the excellent results at mid- and long-term in all patient groups. The author's current indication for a cemented stem include the elderly with no clear and definitive cutoff for age, most likely in females, THA for femoral neck fracture, small femoral canals such as those patients with DDH, and occasionally in patients with history of previous hip infection. Modern and impeccable cement technique is paramount for durable cemented fixation. It is important to remember that the goal is interdigitation of the cement with cancellous bone, so preparing the femur should not remove cancellous bone. Modern technique includes distal plugging of the femoral canal, pulsatile lavage, drying of the femoral canal with epinephrine or hydrogen peroxide, retrograde fill of the femoral canal with cement with appropriate suction and pressurization of the femoral cement into the canal prior to implantation of the femoral component. The dreaded “cement implantation syndrome” leading to sudden death can be avoided by appropriate fluid resuscitation prior to implanting the femoral component. This is an extremely rare occurrence today with reported mortality for the Exeter stem of 1 in 10,000. A cemented femoral component has been shown to be clinically successful at long term. Unfortunately, the art of cementing a femoral component has been lost and is rarely performed in the US. The number of cemented stems, unfortunately, may continue to go down as it is uncommonly taught in residency and fellowship, however, it might find a resurgence as the limits of uncemented fixation in the elderly are encountered. National joint registers support the use of cemented femoral components, and actually demonstrate higher survivorship at short term when compared to all other uncemented femoral components. A cemented femoral component should be in the hip surgeons armamentarium when treating patients undergoing primary and revision THA

The number of cemented femoral stems implanted in the United States continues to slowly decrease over time. Approximately 10% of all femoral components implanted today are cemented, and the majority are in patients undergoing hip arthroplasty for femoral neck fractures. The European experience is quite different, in the UK, cemented femoral stems account for approximately 50% of all implants, while in the Swedish registry, cemented stems still account for the majority of implanted femoral components. Recent data demonstrating some limitations of uncemented fixation in the elderly for primary THA, may suggest that a cemented femoral component may be an attractive alternative in such a group. Two general philosophies exist with regards to the cemented femoral stem: Taper slip and Composite Beam. There are flagship implants representing both philosophies and select designs have shown excellent results past 30 years. A good femoral component design and cementing technique, however, is crucial for long-term clinical success. The authors' personal preference is that of a “taper slip” design. The cemented Exeter stem has shown excellent results past 30 years with rare cases of loosening. The characteristic behavior of such a stem is to allow slight subsidence of the stem within the cement mantle through the process of cement creep. One or two millimeters of subsidence in the long-term have been observed with no detrimental clinical consequences. There have been ample results in the literature showing the excellent results at mid- and long-term in all patient groups. The authors' current indications for a cemented stem include the elderly with no clear and definitive cutoff for age, most likely in females, THA for femoral neck fracture, small femoral canals such as those patients with DDH, and occasionally in patients with history of previous hip infection. Modern and impeccable cement technique is paramount for durable cemented fixation. It is important to remember that the goal is interdigitation of the cement with cancellous bone, so preparing the femur should not remove cancellous bone. Modern technique includes distal plugging of the femoral canal, pulsatile lavage, drying of the femoral canal with epinephrine or hydrogen peroxide, retrograde fill of the femoral canal with cement with appropriate suction and pressurization of the femoral cement into the canal prior to implantation of the femoral component. The dreaded “cement implantation syndrome” leading to sudden death can be avoided by appropriate fluid resuscitation prior to implanting the femoral component. This is a extremely rare occurrence today with reported mortality for the Exeter stem of 1 in 10,000. A cemented femoral component has been shown to be clinically successful at long term. Unfortunately, the art of cementing a femoral component has been lost and is rarely performed in the US. The number of cemented stems unfortunately may continue to go down as it is uncommonly taught in residency and fellowship, however it might find a resurgence as the limits of uncemented fixation in the elderly are encountered. National joint registers support the use of cemented femoral components, and actually demonstrate higher survivorship at short term when compared to all other uncemented femoral components. A cemented femoral component should be in the hip surgeons' armamentarium when treating patients undergoing primary and revision THA

This study aims to identify the efficiency of biomechanical and bioactive properties of the bovine cortical bone cage treated with conditionally surface demineralization. The procured bovine femoral bones were got rid of lipid, protein, and blood materials by chemical process such as 3% hydrogen peroxide and 70% ethanol. The long shaft bones were cut by band saw. Several bone cages were processed by milling machine. The cortical bone cages were demineralized by 0.6N HCl treatment with various conditions, which were the tendency of HCl treatment time, position, direction. After neutralization with pH 7.0, phosphate buffered saline washing and freeze drying process, the vial vacuum packed bone cages were sterilized by 25kGy gamma irradiation. The SEM and EDS system were proceeded for morphology and Ca content in various layers of bone cage. In vitro test for cell viability and differentiation, extracted supernatant from each bone cage by tissue culture was treated in MC3T3E1 cells. For indentifying releasing materials, the others were carried for quantitative analysis by ELISA. After each conditioned period, mRNA expression was compared by RT-PCR. The axial compression and bending strength were measured by universal testing machine (UTM) for biomechanical property. Between the outer layer and inner layer of bone cage for 2 hour’s HCl, there was concentrated Ca extracted layer. The tendency of Ca content and direction of demineralised treatment had effects on the compression and elastic strength. In vitro test, initial Osteogenic transcription factor’s mRNA expression and quantitative result of releasing material had rewarding regulation by HCl-treatment time and treated direction. Conditionally surface demineralized bone cage had good osteoconduc-tivity and osteoinductivity for spinal interbody fusion

The posterior midline approach used in spinal surgery has been associated with a significant rate of wound dehiscence. This study investigates anatomical study of the arterial supply of the cervical and thoracic spinal muscles and overlying skin at each vertebral level. It aimed to provide possible anatomical basis for such wound complications. A dissection and angiographic study was undertaken on 8 cadaveric neck and posterior torso from 6 embalmed and 2 fresh human cadavers. Harvested cadavers were warmed and hydrogen peroxide was injected into the major arteries. Lead oxide contrast mixture was injected in stepwise manner into the subclavian and posterior intercostal arteries of each specimen. Specimens were subsequently cross-sectioned at each vertebral level and bones elevated from the soft tissue. Radiographs were taken at each stage of this process and analysed. The cervical paraspinal muscles were supplied by the deep cervical arteries, transverse cervical arteries and vertebral arteries. The thoracic paraspinal muscles were supplied by the superior intercostal arteries, transverse cervical arteries and posterior intercostal arteries. In the thoracic region, two small vessels provide the longitudinal connection between the segmental arteries and in the cervical region, deep cervical arteries provide such connection from C3 to C6. The arterial vessels supplying the paraspinal muscles on the left and right side anastomose with each other, posterior to the spinous processes in all vertebral levels. At cervical vertebral levels, source arteries travel near the surgical field and are not routinely cauterised; Haematoma is postulated to be the cause of wound complications. At thoracic levels, source arteries travel in the surgical field and tissue ischemia is a contributing factor to wound complications, especially in operations over extensive levels. Post-operative wound complications is a multi-factorial clinical problem, the anatomical findings in this study provide possible explanations for wound dehiscence in the posterior midline approach. It is postulated that drain tubes may reduce the incidence of haematoma in the cervical level

Purpose. The purpose of this study is to compare using a novel cementing technique with hydroxyapatite granules at bone-cement interface with using the 3. rd. cementing technique on the acetabular component. Patients and Methods. Between 2005 and 2007, we performed 54 primary cemented THAs using the 3. rd. generation cementing technique with hydroxyapatite granules at bone-cement interface (Group A: 21 hips) or without them (Group B: 33 hips) in 49 patients with dysplastic hip (6 males, 43 female; mean age at operation, 67 years; age range, 48–84 years). Mean follow up was 5.3 years (range, 2.3–7.1 years), with none of the patients lost to follow up. According to Crowe's classification, subluxation was Group I in 31 hips, group II in 11 hips, group III in 8 hips, and group IV in 4 hips. We used Exeter flanged cup, Exeter stem with a 22-mm diameter metal head (Stryker, Benoist Girard, France) and Simplex-P bone cement (Stryker, Limerick, Ireland) in all hips. A posterolateral approach was performed for all patients. Bone graft was performed 25 hips (block bone graft: 11 hips; impaction bone grafting with a metal mesh: 13 hips) from autogeneic femoral head. Our 3. rd. cementing technique is to make multiple 6-mm anchor holes, to clean the the host acetabular bed with pulse lavage, to dry it with hydrogen peroxide and to use Exeter balloon pressurizer and Exeter flanged cup. Results. The outcomes showed no aseptic loosening and radiological loosening at final follow up. Radiolucent line around the acetabular component was present 14% in Group A and 42% in Group B at 4 years after operation. Kaplan-Meier survivorship analysis of appearance of a radioluent line around the acetabuler component as the end point was 85.7% on group A was significant higher than 57.6% on group B at 4 years. Conclusion. Radiolucent line around cemented acetabular component in total hip arthroplasty using the 3. rd. cementing technique with hydroxyapatite granules at bone-cement interface was significant higher survivorship than them of the 3. rd. cementing technique at 4 years after operation. We suggest that improved novel cementing technique will lead to greater long-term success outcomes of the acetabular component

Introduction: Staphylococcal bacteria, especially the coagulase negative Staphylococci, are responsible for the majority of orthopaedic device related infection. These infections are sub acute, and may not present for months or years following surgery. The virulence of these bacteria is related to their ability to form biofilm, a protective slime which allows them to survive the effects of the host immune system and antimicrobial therapy. Treatment of biofilm based infection almost always necessitates removal of the implant. Recent work has identified environmental stimuli which induce biofilm formation in Staphylococci. These include stressors such as high temperature, high osmolarity, anaerobiosis, nutrient depletion, salt, ethanol and subinhibitory concentrations of certain antimicrobial drugs. Given the ability of these bacteria to survive the “respiratory burst” from the cells of the mononuclear-macrophage system, we hypothesised that oxidative stress may be one such promoter of biofilm formation by Staphylococci. Methods and Materials:Staphylococcus epidermidis CSF41498 and Staphylococcus aureus RN422O were selected for study as these are known biofilm forming organisms. Hydrogen peroxide (H. 2. O. 2. ) was used as an oxidizing agent. Bacteria were incubated for 24 hours at 37°C in Brain-Heart Infusion (BHI, Oxoid) containing progressively weaker concentrations of H. 2. O. 2. to determine a Minimal Inhibitory Concentration (M.I.C.) for the representative strains. Bacterial viability was assessed by measuring the optical density of the incubated culture using a cell density meter (Ultraspec 10, Amersham Biosciences). The bacteria were then grown as a biofilm on a 96 well microtitre plate (Nunc) in the presence of subinhibitory concentrations of H. 2. O. 2. , using pure BHI as a control. Semiquantative determination of biofilm formation was performed by washing the plates, staining the adherent cells with crystal violet, and measuring the light absorbance of the adherent stained cells at 492 nm using a Multiskan plate reader (Flow Laboratories). Results: The M.I.C. of H. 2. O. 2. was 18 mM for both Staphylococcus epidermidis CSF41498 and Staphylococcus aureus RN422O. Concentrations of H. 2. O. 2. of 16 mM and below had no normal bacterial growth and replication. There was no difference in biofilm formation by Staphylococcus epidermidis csf41498 in the presence of 15 mM H. 2. O. 2. when compared to that of the control. However, H. 2. O. 2. had a significant inhibitory effect on biofilm formation by Staphylococcus aureus RN422O, even at a concentration well below the M.I.C. Conclusion: We conclude that oxidative stress may have an antibiofilm action on certain Staphylococcal species, which is independent from its bactericidal effect, and which is manifest at a concentration below the M.I.C. for that species

In hip joint simulator studies, wear measurement is usually performed gravimetrically. This procedure is reliable for metal-on-polyethylene or ceramic-on-polyethylene bearings, in which relatively high amounts of abrasive wear particles are produced. With modern hard-on-hard bearings, volumetric wear decreases significantly up to 100 to 200-fold. The gravimetric method reaches its detection limit with metal-on-metal bearings and even more so with ceramic-on-ceramic bearings. This study establishes a new method of determining wear in hard-on-hard bearings by measuring the amount of worn particles/ions in the serum of hip simulators. A wear study on three resurfacing hip implants (BHR. ®. , Smith& Nephew) was conducted using a hip joint simulator. Prior to the wear study, tests were performed to validate the detection power for high resolution-inductively coupled plasma-mass spectrometry (HR-ICP-MS). More importantly the system’s accuracy was compared to the gravimetric method, which is described in ISO 14243-2. The simulator was altered to run completely metal ion free. The ion concentration in the serum was measured every 100 000 cycles up to 1 500 000 cycles and subsequently in intervals of 500 000 cycles using HR-ICP-MS. The implants were neither removed from the simulator nor excessively cleaned during the course of the simulation. Serum was refreshed every 500 000 cycles. The serum samples were digested with purified nitric acid and hydrogen peroxide using a high pressure microwave autoclave in order to measure wear particles as well as dissolved ions. All steps were carried out under clean room conditions. Wear was calculated using the ion concentration and measured serum volume. Wear rates and transition from running-in to steady-state wear phases were calculated. A detection power better than 0.028 μg/l for Co (cobalt), 0.017 μg/l for Cr (chromium) and 0.040 μg/l for Mo (molybdenum) was found for HR-ICP-MS. The validation of HR-ICP-MS showed good agreement between gravimetric data and measured ion concentrations. The tested implants showed similar wear behaviour. Implant wear resulted in high ion concentrations during the first 380 000 to 920 000 cycles. During this period, a mean wear rate of 6.96 mm3/10E6 cycles was determined. Subsequently, the wear rate significantly decreased to a mean wear rate of 0.37 mm3/10E6 cycles. Thus, a mean ratio between running-in and steady-state wear of 18.8 was found. The mean overall wear volume at the end of the simulation was 4.42 mm3. This study showed that measuring the ion concentrations in the serum of hip simulators can be used to determine wear in metal-on-metal bearings. The main advantages of this new method are the ability to detect ultra-low wear rates and to precisely specify the duration of different wear phases. Because the implants do not have to be removed from the simulator and aggressive cleaning processes may be skipped, fluctuations in wear detection are extremely low. This in turn leads to a shorter duration of the simulation. Wear rates of the tested implants are low compared to polyethylene. Transferring the results to patient activity, wear would be the same during the first four to six months after implantation as in the next ten years. Minimizing the duration of running-in would be most effective in further reducing wear of metal-on-metal bearings

Introduction. Large diameter femoral heads offer increased range of motion and reduced risk of dislocation. However, their use in total hip arthroplasty has historically been limited by their correlation with increased polyethylene wear. The improved wear resistance of highly crosslinked UHWMPE has led a number of clinicians to transition from implanting traditionally popular sizes (28mm and 32 mm) to implanting 36 mm heads. Desire to further increase stability and range of motion has spurred interest in even larger sizes (> 36 mm). While the long-term clinical ramifications are unknown, in-vivo measurements of highly crosslinked UHMWPE liners indicate increases in head diameter are associated with increased volumetric wear [1]. The goal of this study was to determine if this increase in wear could be negated by using femoral heads with a ceramic surface, such as oxidized Zr-2.5Nb (OxZr), rather than CoCrMo (CoCr). Specifically, wear of 10 Mrad crosslinked UHMWPE (XLPE) against 36 mm CoCr and 44 mm OxZr heads was compared. Materials and Methods. Ram-extruded GUR 1050 UHMWPE was crosslinked by gamma irradiation to 10 Mrad, remelted, and machined into acetabular liners. Liners were sterilized using vaporized hydrogen peroxide and tested against either 36 mm CoCr or 44 mm OxZr (OXINIUM(tm)) heads (n=3). All implants were manufactured by Smith & Nephew (Memphis, TN). Testing was conducted on a hip simulator (AMTI, Watertown, MA) as previously described [2]. The 4000N peak load (4 time body weight for a 102 kg/225 lb patient) and 1.15 Hz frequency used are based upon data obtained from an instrumented implant during fast walking/jogging and have previously been shown to generate measurable XLPE wear [2,3]. Lubricant was a serum (Alpha Calf Fraction, HyClone Laboratories, Logan, UT) solution that was replaced once per week [2]. Liners were weighed at least once every million cycles (Mcycle) over the duration of testing (∼ 5 Mcycle). Loaded soak controls were used to correct for fluid absorption. Single factor ANOVA was used to compare groups (a = 0.05). Results. The predominant wear feature displayed on the articular surface of liners was burnishing. There were no signs of fatigue wear or of delamination. Mean wear rates (± std dev) of liners articulated against 36mm CoCr and 44 mm OxZr heads were 3.7 ± 0.4 mm. 3. /Mcycle and 2.7 ± 0.4 mm. 3. /Mcycle, respectively (Figure 1). This difference was statistically significant (p = 0.04). Discussion. Although large diameter heads offer biomechanical advantages, their use in total hip arthroplasty has historically been limited due to correlation with increased polyethylene wear. While highly crosslinked liners exhibit significantly improved wear resistance over conventional UHWMPE, their wear has also been shown to increase with head size [1]. Results presented here indicate that this increase in wear can be negated by using OxZr, rather than CoCr. Specifically, wear of XLPE liners was lower against 44 mm OxZr heads than against 36 mm CoCr heads

Aims

In this investigation, we administered oxidative stress to nucleus pulposus cells (NPCs), recognized DNA-damage-inducible transcript 4 (DDIT4) as a component in intervertebral disc degeneration (IVDD), and devised a hydrogel capable of conveying small interfering RNA (siRNA) to IVDD.