Aims. Trained immunity confers non-specific protection against various types of infectious diseases, including bone and joint infection. Platelets are active participants in the immune response to pathogens and foreign substances, but their role in trained immunity remains elusive. Methods. We first trained the innate immune system of C57BL/6 mice via
Aims. Methicillin-resistant Staphylococcus aureus (MRSA) can cause wound infections via a ‘Trojan Horse’ mechanism, in which neutrophils engulf intestinal MRSA and travel to the wound, releasing MRSA after apoptosis. The possible role of intestinal MRSA in prosthetic joint infection (PJI) is unknown. Methods. Rats underwent intestinal colonization with green fluorescent protein (GFP)-tagged MRSA by gavage and an intra-articular wire was then surgically implanted. After ten days, the presence of PJI was determined by bacterial cultures of the distal femur, joint capsule, and implant. We excluded several other possibilities for PJI development. Intraoperative contamination was excluded by culturing the specimen obtained from surgical site. Extracellular bacteraemia-associated PJI was excluded by comparing with the infection rate after
Aim. Tourniquet is widely used in extremity surgery. In order to prevent surgical site infection, correct timing of antimicrobial prophylaxis and tourniquet inflation is important. We aimed to evaluate the time for which the free drug concentration of cefuroxime is maintained above the minimal inhibitory concentration (T>MIC) in subcutaneous tissue and calcaneal cancellous bone during three clinically relevant tourniquet application scenarios. Method. Twenty-four female pigs were included. Microdialysis catheters were placed for sampling of cefuroxime concentrations bilaterally in calcaneal cancellous bone and subcutaneous tissue, and a tourniquet cuff was applied on a randomly picked leg of each pig. Subsequently, the pigs were randomized into three groups to receive 1.5 g of cefuroxime by
Tourniquet is widely used in extremity surgery. In order to prevent surgical site infection, correct timing of antimicrobial prophylaxis and tourniquet inflation is important. We aimed to evaluate the time for which the free drug concentration of cefuroxime is maintained above the minimal inhibitory concentration (T>MIC) in subcutaneous tissue and calcaneal cancellous bone during three clinically relevant tourniquet application scenarios. Twenty-four female pigs were included. Microdialysis catheters were placed for sampling of cefuroxime concentrations bilaterally in calcaneal cancellous bone and subcutaneous tissue, and a tourniquet cuff was applied on a randomly picked leg of each pig. Subsequently, the pigs were randomized into three groups to receive 1.5 g of cefuroxime by
Introduction. Recently, oxidative stress has been implicated in the development of osteonecrosis. Here we focused on vitamins with marked antioxidant potency to see whether their use might prevent the development of osteonecrosis associated with corticosteroid administration. Methods. Fifteen male Japanese white rabbits weighing about 3.5 kg were injected once into the right gluteal muscle with methylprednisolone (MPSL) 40 mg/kg (S Group). Ten other rabbits, in addition, received consecutive daily
INTRODUCTION. Adequate osseointegration of knee resurfacing implants for the treatment of focal cartilage defects is an important prerequisite for good clinical outcomes. Inadequate initial fixation and sustained micromotion may lead to osteolysis and ultimately implant failure. PET/CT with the bone seeking tracer 18F-sodium fluoride (18F-NaF) allows for localisation and quantification of abnormalities in bone metabolism. 18F-NaF PET/CT has been shown to correlate with loosening of implants in the hip and spine. Here, we asses osseointegration of the knee resurfacing implants using micro-computed tomography (µCT) and correlate µCT parameters to 18F-NaF uptake on PET/CT scans taken 3 and 12 weeks after surgery. We hypothesize that 18F-NaF uptake at 12 weeks and its relative decrease between 3 and 12 weeks correlates with osseointegration at 12 weeks postoperatively. Polymer implants with Young”s moduli approximately equal to- and below the Young's modulus of bone, with- and without surface modification were used in this study next to a control metal implant. METHODS. Five different osteochondral implants were implanted bilaterally in critically-sized osteochondral defects in 16 goats. At 3 and 12 weeks postoperatively, a 10-minute static PET/CT-scan (Philips, Gemini TF PET/CT) was made 60 minutes after
MSCs (mesenchymal stem cells) are bone marrow-derived cells capable of replication and differentiation in-vitro into several tissues including bone, cartilage, stroma, fat, muscle and tendon. MSCs can be isolated by relatively simple procedures and then expanded without losing the ability to differentiate into multiple lineages. As such, these cells have immense clinical potential in regenerative medicine and in orthopaedics for repair or replacement of damaged tissues. In this work we investigated the interaction between magnetic carbon nanotubes (CNTs) and MSCs and their ability to guide these cells injected intravenously in living mice by using an external magnetic field. CNTs did not affect cell viability and their ability to differentiate. Both the CNTs and the magnetic field did not alter cell growth rate, phenotype and cytoskeletal conformation. CNTs, when exposed to magnetic fields, are able to shepherd MSCs towards the magnetic source in vitro. Moreover, the application of a magnetic field alters the biodistribution of CNT-labelled MSCs after
The clinical success of posterior lumbar interbody fusion (PLIF) may be limited by pseudarthrosis, defined as the absence of solid fusion 1 year after surgery. Currently, CT is used to diagnose pseudarthrosis but is not able to be conclusive earlier than 1 year after surgery. No non-invasive technique is available to reliably assess bone graft incorporation in the early phase after PLIF. Positron Emission Tomography (PET) is a nuclear imaging modality that is able to identify changes at the cellular and molecular level in an early stage, well before manifestation of anatomical changes. PET/CT with the bone seeking tracer . 18. F-fluoride allows localization and quantification of bone metabolism. This study investigates whether an . 18. F-fluoride PET/CT scan early after PLIF is able to predict the fusion status at 1 year postoperative on CT. Twenty patients after PLIF were enrolled after written informed consent. At 6 weeks and at 1 year after PLIF,
We aimed to measure cerebral microemboli load during total hip [THA] and knee arthroplasty (TKA) using transcranial Doppler ultrasound (TCD) and to investigate whether cerebral embolic load influences neuropsychiatric outcome. The timing of the microemboli was also related to certain surgical activities to determine if a specific relationship exists and the presence of a patent foramen ovale was investigated. Patients undergoing primary THA and TKA underwent a battery of ten neuropsychiatric tests pre-operatively and at 6 weeks and 6 months post-operatively. Microembolic load was recorded using TCD onto VHS tape for subsequent analysis. Patent foramen ovale detection was performed using bolus
A prospective, randomized, double-blind study was done on 50 patients undergoing primary cementless total hip arthroplasty to determine the effect of tranexamic acid on intra- and postoperative blood losses and on the transfusions requirements. 50 patients were randomized to tranexamic acid (15 mg/kg) given as a bolus
Background: Confusion occurs in up to 60% of patients following neck of femur fracture, delaying hospital discharge. We investigated venous – arterial circulation shunts (v-aCS) and the influence of cerebral embolism before and during surgery on subsequent cognitive function. Methods: Cerebral emboli were counted in 16 patients with an inter-trochanteric or Garden III/IV fracture by transcranial Doppler (TCD) monitoring over 1 hour pre-operatively and intra-operatively. A v-aCS was diagnosed when 1 or more microbubbles were detected in the middle cerebral artery by TCD following
Background: Cerebral emboli may be detected by transcranial Doppler (TCD) in patients undergoing hip arthroplasty. Venous – arterial circulation shunts (v-aCS), cerebral embolism and postoperative organ dysfunction were investigated in elective hip arthroplasty. Methods: TCD was used to identify v-aCS in (i) elective hip arthroplasty (n=45), (ii) abdominal aortic aneurysm surgery (AAA) (n=20) and (iii) transurethral resection of prostate (TURP) (n=10). A v-aCS was diagnosed when 1 or more microbubbles were detected in the middle cerebral artery by TCD following
A prospective, randomized, double-blind study was done on 50 patients undergoing primary cementless total hip arthroplasty to determine the effect of tranexamic acid on intra- and postoperative blood losses and on the transfusions requirements. 50 patients were randomized to tranexamic acid (15 mg/kg) given as a bolus
Introduction. Tranexamic acid is an inhibitor of fibrinolysis that blocks the lysine-binding site of plasminogen to fibrin, and thereby decreases blood loss in patients undergoing surgery. Aims and objectives. A prospective, randomized, double-blind study was done on 100 patients undergoing primary cemented Unilateral Total Knee Arthroplasty to determine the effect of tranexamic acid on intra- and postoperative blood losses and on the transfusions requirements. Material and Methods. 100 patients undergoing unilateral cemented total knee Arthroplasty for osteoarthritis were enrolled for the study. All total knee replacement was done under combined spinal epidural anaesthesia with the use of tourniquet. 100 patients were randomized to tranexamic acid (15 mg/kg) given as a bolus
Summary. The two-step labeling protocol using Lysostaphin and bio-orthogonal click chemistry for staining bacteria is described. The click protocol is efficient in labeling staphylococci and is non-toxic. This protocol promises the efficient of infections that are difficult to assess by conventional imaging. Introduction. Infection diagnostics in clinics is time consuming, invasive and relays on microbiological cultures. New probes and labeling protocols enabling rapid and specific detection of infection in vivo shall improve the situation. We investigated the potential of a new click labeling protocol to detect staphylococci. Azido (N3) - modified Lysostaphin and DIBO (Di-benzocyclooctyne) - dye were used in the two-step bacteria-labeling protocol. N3 and DIBO were the counterparts of the bioorthogonal “click” reaction. In the first step, Lysostaphin-N3 bound to Staphylococcus aureus. In the second step, N3 clicked to DIBO thus achieving S. aureus selective labeling. Methods. S. aureus NCTC 10788 and E. coli NCTC 12241 (from National Collection of Type Cultures), primary sheep osteoblasts and C57BL/6 mice were used for this study. DIBO-Alexa488 (Invitrogen ®), DyeLight488 (Thermofisher ®), NHS-N3 (Lumiprobe ®), Lysostaphin (Sigma-Aldrich ®) were purchased. In vitro we used standard microbiological protocols to assess antimicrobial and labeling activity of the “click” probe (Lysostaphin-N3 plus DIBO-dye), one-step-labeled Lysostaphin-Dye and non-labeled Lysostaphin. Flow cytometry, Fluorescence microscopy, and Spectrophotometry were employed to measure binding of the probes to bacteria. The cytotoxicity of the probes on osteoblasts was performed using Presto Blue Cell Viability test (Invitrogen ®). In vivo we used Fluorescence Intravital Microscopy and mice with dorsal skin-fold chambers (approved by the local governmental animal care committee). Subsequently to anesthesia each mouse received S. aureus strain Cowan I intravenously. This was followed by
To quantify the intraoperative cerebral microemboli load during primary total knee arthroplasty (TKA) using transcranial Doppler ultrasound and to investigate whether a patent foramen ovale influences cerebral embolic load in general. Patients undergoing primary TKA, with no history of stroke, TIA, ongoing CNS disease or alcoholism were included. All operations were carried out under a standardised general anaesthetic and performed by two consultant orthopaedic surgeons. Microemboli l oad was recorded, using transcranial Doppler ultrasound (TCD), onto VHS tape for subsequent playback and analysis. Patent foramen ovale detection was performed using bolus
Osteoprotegerin (OPG) has been reported to be a novel protein that can suppress osteoclast differentiation and activation. This study examined the therapeutic effects of OPG on established periprosthetic osteolysis in a rat model. A bone cement prosthesis was inserted into the rat femur and polyethylene particles were continuously infused into the knee joint using an osmotic pump. After osteolysis was established in four weeks, rats were intravenously injected with vehicle (control group) or 1 mg/kg of OPG (OPG-1 group) or 10 mg/kg of OPG (OPG-10 group) every week until they were sacrificed at 8 weeks. Effects of direct injections of OPG into the knee joint were also investigated. Periprosthetic bone resorption was evaluated with bone mineral density and histomorphometric analysis of membranes composed of total area of interface membrane and inflammatory grading. Radiographs were evaluated for focal osteolysis with a blind manner. Periprosthetic bone resorption was significantly suppressed in OPG-10 group compared to the other groups (p <
0.05). Histomorphometric analyses showed less total area as well as less inflammatory grading of the interface membrane in OPG-10 group compared to other groups (p <
0.01). Radiographic osteolysis appeared to decrease in number in OPG-10 group. Direct injections of OPG into the knee joint appeared to be more effective compared to
Introduction: Surgery in the foot and ankle is usually performed under general or spinal anaesthesia. Peripheral nerve blocking is gaining the preference of both surgeons and patients. The aim of this study is to evaluate the adequacy of anaesthesia with the method of triple nerve blocking at the region of the knee. Materials and methods: One hundred and forty-four patients (79 men and 65 women) that were diagnosed with ankle and foot injuries or diseases underwent surgery using triple nerve blocking at the knee region as a method of anaesthesia. Surgical procedures included bone and soft tissue procedures and especially fracture fixation, osteotomies, tendon repairs, neuroma and tumor excisions, nerve decompressions and arthrodeses. The common peroneal, tibial and saphenous nerves were blocked with injection of 8 ml ropivacaine 2% for each nerve. The injection was performed by an Orthopaedic surgeon with the use of a neurostimulator. An anesthesiologist was available when necessary. Results: Ninety-four patients tolerated the procedure without the need of additional injection of anaesthesia or analgesia. In 45 patients additional injection of local anesthetic was necessary. Five patients needed
Aims: To compare the intraoperative cerebral microemboli load between primary total hip (THA) and knee arthroplsty (TKA) using transcranial Doppler ultrasound and to investigate whether a patent foramen ovale influences cerebral embolic load in general. The timing of the microemboli will be related to certain surgical activities to determine if a specific relationship exists. Methods: Patients undergoing primary TKA or THA, with no history of stroke, TIA, ongoing CNS disease or alcoholism included. All operations carried out under a standardised general anaesthetic and performed by two consultant orthopaedic surgeons. Microemboli load recorded, using transcranial Doppler ultrasound (TCD), onto VHS tape for subsequent playback and analysis. Patent foramen ovale detection performed using bolus
Aims: To quantify the intraoperative cerebral microemboli load during primary total hip arthroplasty (THA) using transcranial Doppler ultrasound and to investigate whether a patent foramen ovale influences cerebral embolic load in general. The timing of the microemboli will be related to certain surgical activities to determine if a specific relationship exists. Methods: Patients undergoing primary THA, with no history of stroke, TIA, ongoing CNS disease or alcoholism were included. All operations were carried out under a standardised general anaesthetic and performed by two consultant orthopaedic surgeons. Microemboli load was recorded, using transcranial Doppler ultrasound (TCD), onto VHS tape for subsequent playback and analysis. Patent foramen ovale detection was performed using bolus
