Healthcare associated infections (HAI) pose a major threat to patients admitted to hospitals, and infection rates following orthopaedic arthroplasty surgery are as high as 4%, while the infection rates are even higher after revision surgery. 405 nm High-Intensity Narrow Spectrum (HINS) light has been proven to reduce environmental contamination in hospital isolation rooms, and there is potential to develop this technology for application in orthopaedic surgery. Cultured rat osteoblasts were exposed to 405 nm light to investigate if bactericidal doses of light could be used safely in the presence of mammalian cells. Cell viability was measured by MTT reduction and microscopy techniques, function by alkaline phosphatase activity, and proliferation by the BrdU assay. Exposures of up to a dose of 36 J/cm. 2. had no significant effect on osteoblast cell viability, whilst exposure of a variety of clinically relevant bacteria, to 36 J/cm. 2. resulted in up to 100% kill. Exposure to a higher dose of 54 J/cm. 2. significantly affected the osteoblast cell viability, indicating dose dependency. Work also demonstrated that 405 nm light exposure induces reactive oxygen species (ROS) production in both mammalian and bacterial cells, as shown by fluorescence generated from 6-carboxy-2′,7′-dichlorodihydrofluorescein diacetate dye. The mammalian cells were significantly protected from dying at 54 J/cm. 2. by catalase, which detoxifies H. 2. O. 2. Bacterial cells were significantly protected by sodium pyruvate (H. 2. O. 2. scavenger) and by a combination of free radical scavengers (sodium pyruvate, dimethyl thiourea (·OH scavenger), catalase) at 162 and 324 J/cm. 2. Thus the cytotoxic mechanism of 405 nm light in mammalian cells and bacteria is likely oxidative stress involving predominantly H. 2. O. 2. generation, with other ROS contributing to the damage. Additional work describing the potential for incorporation of this antimicrobial light within operating theatre lighting systems will also be discussed, and this, coupled with the cell viability and cytotoxicity results, suggests that 405 nm light could have great potential for continual patient safe decontamination during orthopaedic replacement surgeries and thereby reduce the incidence of infections

Objectives. Surgeons face a substantial risk of infection because of the occupational exposure to blood-borne pathogens (BBPs) from patients undergoing high-risk orthopaedic procedures. This study aimed to determine the seroprevalence of four BBPs among patients undergoing joint arthroplasty in Shanghai, China. In addition, we evaluated the significance of pre-operative screening by calculating a cost-to-benefit ratio. Methods. A retrospective observational study of pre-operative screening for BBPs, including hepatitis B and C viruses (HBV and HCV), human immunodeficiency virus (HIV) and Treponema pallidum (TP), was conducted for sequential patients in the orthopaedic department of a large urban teaching hospital between 01 January 2009 and 30 May 2016. Medical records were analysed to verify the seroprevalence of these BBPs among the patients stratified by age, gender, local origin, type of surgery, history of previous transfusion and marital status. Results. Of the subjects who underwent arthroplasty surgery in our institution, pre-operative screening tests were available for 96.1% (11 609 patients). The seroprevalence of HBV, HCV, HIV and TP was 5.47%, 0.45%, 0.08% and 3.6%, respectively. A total of 761 seropositive cases (68.4%) were previously undiagnosed. Pre-operative screening for HIV resulted in a low cost to benefit ratio, followed by HCV and HBV. Conclusion. Routine HCV and HIV screening prior to joint arthroplasty is not a cost-effective strategy. Considering the high rate of undiagnosed patients and the shortage of protective options, targeted pre-operative screening for HBV and syphilis should be considered for the protection of healthcare workers in China who have not been vaccinated. Cite this article: Bone Joint Res 2017;6:566–571

Background. Stress shielding and wear induced aseptic loosening cause failure in arthroplasty surgery. To improve survivorship, the use of a low modulus, low wearing biomaterial may be a suitable alternative to hard bearing prostheses, such as cobalt chromium (CoCr). There has been considerable research interest in the use of polyetheretherketone (PEEK) based on observed clinical success especially in spinal surgery. This study investigated the wear performance of PEEK, carbon reinforced PEEK (CFR-PEEK) and acetal as bearing materials in an all polymer total knee arthroplasty (TKA) using a unidirectional pin on plate test. Methods. The following material combinations were tested: PEEK vs. UHMWPE, CFR-PEEK vs. UHMWPE, PEEK vs. PEEK, CFR-PEEK vs. PEEK, CoCr vs. UHMWPE, PEEK vs. XLPE, CFR-PEEK vs. CFR-PEEK, PEEK vs. Acetal, Acetal vs. XLPE and CoCr vs. XLPE.Tribological couples tested (Pin vs. Plate) Using a previously validated modification of ASTM F732, 20mm diameter spherically ended pins with a radius of 25mm were articulated against 40mm diameter plates. A load of 1000N was applied to generate a contact stress of about 70MPa similar to contact stresses previously reported in the knee. The lubricant used was 25% newborn calf serum containing 0.3% sodium azide to retard bacteria growth and 20mM EDTA to prevent calcium deposition. Three repeats of pin on plate combinations (including 2 passive soak controls) were tested for 2 million cycles at a cycle frequency of 1Hz and a stroke length of 10 mm. Gravimetric wear was analysed every 250,000 cycles and results converted to volumetric wear using material density. Results. All CFR-PEEK articulations were stopped due to excessive wear of the counter-surfaces. Results showed a linear wear rate of UHMWPE and XLPE plates over the test period. PEEK vs. XLPE showed similar wear rate to metal on polyethylene (MoP) bearings. Conclusion. At stresses representative of the knee, PEEK pins when articulated against XLPE plates generated volumetric wear similar to that noted in MoP bearings

Summary Statement. Routine metal allergy screening prior to joint arthroplasty is not essential and the use of cobalt chromium or stainless steel implants is recommended regardless of the patient's metal allergy status. Introduction. This study was undertaken to obtain a consensus amongst joint arthroplasty experts with regards to metal allergy screening prior to joint arthroplasty and the choice of implant in patients with potential metal allergy. Patients & Methods. A web based Delphi consensus study was used including orthopaedic surgeons that had previously published on the topic of knee, hip or shoulder arthroplasty. Two rounds of questionnaires were sent via electronic mail. Consensus was considered if agreement was 60% or higher. Results. 18 surgeons responded to the first and 17 to the second round of questionnaires. There was consensus that patients having metal arthroplasty surgery should not be routinely questioned about metal allergy prior to surgery. There was consensus that patch testing is not necessary even if metal allergy is suspected. Most respondents agreed in proceeding with cobalt chromium or stainless steel implant in patients suspected of metal allergy regardless of the results of cutaneous patch testing. Discussion/Conclusion. This consensus study suggests that routine metal allergy screening prior to joint arthroplasty is not essential. The use of traditional cobalt chromium/stainless steel implants is recommended regardless of the patient's metal allergy status

Aims. Osteoporosis and abnormal bone metabolism may prove to be significant factors influencing the outcome of arthroplasty surgery, predisposing to complications of aseptic loosening and peri-prosthetic fracture. We aimed to investigate baseline bone mineral density (BMD) and bone turnover in patients about to undergo arthroplasty of the hip and knee. Methods. We prospectively measured bone mineral density of the hip and lumbar spine using dual-energy X-ray absorptiometry (DEXA) scans in a cohort of 194 patients awaiting hip or knee arthroplasty. We also assessed bone turnover using urinary deoxypyridinoline (DPD), a type I collagen crosslink, normalised to creatinine. Results. The prevalence of DEXA proven hip osteoporosis (T-score ≤ -2.5) among hip and knee arthroplasty patients was found to be low at 2.8% (4 of 143). Spinal osteoporosis prevalence was higher at 6.9% (12 of 175). Sixty patients (42% (60 of 143)) had osteopenia or osteoporosis of either the hip or spine. The mean T-score for the hip was -0.34 (. sd. 1.23), which is within normal limits, and the mean hip Z-score was positive at 0.87 (. sd. 1.17), signifying higher-than-average BMD for age. The median urinary DPD/creatinine was raised in both female patients at 8.1 (interquartile range (IQR) 6.6 to 9.9) and male patients at 6.2 (IQR 4.8 to 7.5). Conclusions. Our results indicate hip and knee arthroplasty patients have higher BMD of the hip and spine compared with an age-matched general population, and a lower prevalence of osteoporosis. However, untreated osteoporotic patients are undergoing arthroplasty, which may negatively impact their outcome. Raised DPD levels suggest abnormal bone turnover, requiring further investigation. Cite this article: Bone Joint Res 2014;3:14–19

Infection rates following arthroplasty surgery are between 1–4%, with higher rates in revision surgery. The associated costs of treating infected arthroplasty cases are considerable, with significantly worse functional outcomes reported. New methods of infection prevention are required. HINS-light is a novel blue light inactivation technology which kills bacteria through a photodynamic process. The aim of this study was to investigate the efficacy of HINS-light for the inactivation of bacteria isolated from infected arthoplasty cases. Specimens from hip and knee arthroplasty infections are routinely collected to identify causative organisms. This study tested a range of these isolates for sensitivity to HINS-light. During testing, bacterial suspensions were exposed to increasing doses of HINS-light of (123mW/cm. 2. irradiance). Non-light exposed control samples were also set-up. Bacterial samples were then plated onto agar plates and incubated at 37°C for 24 hours before enumeration. Complete inactivation was achieved for all Gram positive and negative microorganisms. More than a 4-log reduction in Staphylococcus epidermidis and Staphylococcus aureus populations were achieved after exposure to HINS-light for doses of 48 and 55 J/cm. 2. , respectively. Current investigations using Escherichia coli and Klebsiella pneumoniae show that gram-negative organisms are also susceptible, though higher doses are required. This study has demonstrated that HINS-light successfully inactivated all clinical isolates from infected arthroplasty cases. As HINS-light utilises visible-light wavelengths it can be safely used in the presence of patients and staff. This unique feature could lead to possible applications such as use as an infection prevention tool during surgery and post-operative dressing changes

Infection rates following arthroplasty surgery are between 1–4%, with higher rates in revision surgery. The associated costs of treating infected arthroplasty cases are considerable, with significantly worse functional outcomes reported. New methods of infection prevention are required. HINS-light is a novel blue light inactivation technology which kills bacteria through a photodynamic process. The aim of this study was to investigate the efficacy of HINS-light for the inactivation of bacteria isolated from infected arthroplasty cases. Specimens from hip and knee arthroplasty infections are routinely collected to identify causative organisms. This study tested a range of these isolates for sensitivity to HINS-light. During testing, bacterial suspensions were exposed to increasing doses of HINS-light of (123 mW/cm. 2. irradiance). Non-light exposed control samples were also set-up. Bacterial samples were then plated onto agar plates and incubated at 37°C for 24 hours before enumeration. Complete inactivation (greater than a 4-log reduction) was achieved for all of the clinical isolates from infected arthroplasty cases. The typical inactivation curve showed a slow initial reaction followed by a period of rapid inactivation. The doses of HINS-light exposure required ranged from 118–2214 J/cm. 2. respectively. Gram-positive bacteria were generally found to be more susceptible than Gram-negative. This study has demonstrated that HINS-light successfully inactivated all clinical isolates from infected arthroplasty cases. As HINS-light utilises visible-light wavelengths it can be safely used in the presence of patients and staff. This unique feature could lead to possible applications such as use as an infection prevention tool during surgery and post-operative dressing changes

Aim of the study was to evaluate if abrasion-arthroplasty (AAP) and abrasion-chondroplasty (ACP) leads to a release of mesenchymal stem cell (MSC) like cells from the bone marrow to the joint cavity where they probably differentiate into a chondrogenic phenotype. Introduction. Cartilage demage is a sever problem in our aging society. About 5 million people only in Germany are affected. Osteoathritis is a degeneration of cartilage caused by aging or traumata 50 % of the people over 40 have signs of osteoarthritis. But the ability of self-regeneration of cartilage is strongly limited. There are different approaches to therapy osteoathritic lesions. Arthroscopic treatment of OA includes bone marrow stimulation technique such as abrasion arthroplasty (AAP) and microfracturing (MF). Beside the support of chondrocyte progenitor cells the environment is also important for the commitment to chondrocytes. Therefore insulin-like growth factor-1 (IGF-1) and transforming growth factor beta-1 (TGF-β1) are important factors during the regeneration process. In the present study we characterised the heamarthrosis and the released cells after AAP and its ability to differentiate into the chondrocyte lineage. Material and Methods. Postoperative haemarthrosis was taken 5, 22 or 44 hours after surgery. 7.5 mg Dexamethasone (Corticosteroid) was administered into the knee joint to prevent postoperative inflammation. Mononuclear cells were isolated from haemarthrosis from the drainage bottle by ficoll density gradient centrifugation. The isolated cells were characterised using fluorescence-activated cell-sorting (FACS) analysis for characteristic markers of MSC such as CD 44, 73, 90, 105. After expanding cells were cultured in a pellet culture. After 3 weeks, histochemistry and immunohistochemistry against Sox9, collagen II and proteoglycan were performed. The release of IGF1, BMP4 and BMP7 was analysed in haemarthrosis serum by ELISA and Luminex technology. Results. The isolated cells after AAP are positive for the mesenchymal stem cell marker CD105, CD90, CD73, CD 44 and negative for the marker of hematopoetic stem cells CD 34. Isolated cells after ACP couldn't be expanded for further characterizations. The staining of the 3D-culture revealed a positive signal for the chondrogen transcription factor Sox9 and the expression of extracellular markerproteins like collagen type II and proteoglycan. Both surgery techniques, AAP and ACP provides a chondrogenic environment. We were able to detect IGF-1, TGFß, BMP4 and BMP7 in the haemarthrosis. Discussion. The benefit of abrasion arthroplasty surgery and microfracturing is controversial discussed because they do not consistently result in hyaline cartilage. But the opening of the bone marrow allows the release of monocytic cells which have the potential to differentiate into a chondrogenic phenotype. In 3D-culture these cells express Sox9 and a collagen proteoglycan rich matrix. The haemarthrosis provides also a cartilage-stimulating environment. We could detect IGF1, TGFβ, BMP4 and 7 which could enhance the commitment concerning differentiation of MSCs to a chondrogenic lineage concerning the production of cartilage specific extracellular matrix. Taken together our study provides the evidence for a therapeutic benefit of opening bone marrow in order to generate neocartilage after AAP

Objectives

This study reports on a secondary exploratory analysis of the early clinical outcomes of a randomised clinical trial comparing robotic arm-assisted unicompartmental knee arthroplasty (UKA) for medial compartment osteoarthritis of the knee with manual UKA performed using traditional surgical jigs. This follows reporting of the primary outcomes of implant accuracy and gait analysis that showed significant advantages in the robotic arm-assisted group.

Objectives

We have increased the dose of tranexamic acid (TXA) in our enhanced total joint recovery protocol at our institution from 15 mg/kg to 30 mg/kg (maximum 2.5 g) as a single, intravenous (IV) dose. We report the clinical effect of this dosage change.

Objectives

To review the current best surgical practice and detail a multi-disciplinary approach that could further reduce joint replacement infection.