Biofabrication of soft tissue templates for engineering the bone-ligament interface.

Regenerating damaged tissue interfaces remains a significant clinical challenge, requiring recapitulation of the structure, composition, and function of the native enthesis. In the ligament-to-bone interface, this region transitions from ligament to fibrocartilage, to calcified cartilage and then to bone. This gradation in tissue types facilitates the transfer of load between soft and hard structures while minimizing stress concentrations at the interface. Previous attempts to engineer the ligament-bone interface have utilized various scaffold materials with an array of various cell types and/or biological cues. The primary goal of this study was to engineer a multiphased construct mimicking the ligament-bone interface by driving differentiation of a single population of mesenchymal stem cells (MSCs), seeded within blended fibrin-alginate hydrogels, down an endochondral, fibrocartilaginous, or ligamentous pathway through spatial presentation of growth factors along the length of the construct within a custom-developed, dual-chamber culture system. MSCs within these engineered constructs demonstrated spatially distinct regions of differentiation, adopting either a cartilaginous or ligamentous phenotype depending on their local environment. Furthermore, there was also evidence of spatially defined progression toward an endochondral phenotype when chondrogenically primed MSCs within this construct were additionally exposed to hypertrophic cues. The study demonstrates the feasibility of engineering spatially complex soft tissues within a single MSC laden hydrogel through the defined presentation of biochemical cues. This novel approach represents a new strategy for engineering the ligament-bone interface. Biotechnol. Bioeng. 2017;114: 2400-2411. © 2017 Wiley Periodicals, Inc.

A Long-term Retrospective Evaluation of Functional and Radiographic Outcomes of Pediatric Hip Surgery in Hurler Syndrome.

BACKGROUND: After successful hematopoietic stem cell transplantation, maintaining function and mobility have become key goals in the management of patients with Hurler syndrome, (mucopolysaccharoidosis type 1H). The aim of this study was to establish the functional and radiologic outcomes after hip surgery in patients with this condition who had reached skeletal maturity. METHODS: We prospectively followed 13 mucopolysaccharoidosis type 1H patients with closed triradiate cartilages who had undergone hip surgery in a single institution (Our Lady's Children's Hospital, Crumlin) in early childhood, after successful hematopoietic stem cell transplantation. Functional assessment was performed using the Harris Hip Score. Acetabular and femoral head morphology were defined using a pelvic radiograph. RESULTS: The average age at follow-up was 18.6 years (range, 13.2 to 23.8 y). The average length of follow-up from surgical intervention was 14.6 years (range, 10.3 to 21.6 y). The average Harris Hip Score at follow-up was 61.0 (range, 19 to 91). At follow-up, 4 patients were either wheelchair bound or required a walking frame to mobilize in the community. At follow-up, all hips were in-joint with an average center edge angle of 37.7 degrees (range, 0 to 63 degrees). All hips displayed characteristic medial flattening of the femoral head. Ten hips (of 26 hips) showed radiologic degenerative changes with loss of joint space <2 mm. CONCLUSIONS: Despite the surgical provision of stable well-covered hips, active intervention did not prevent the development of radiologic deterioration and clinically significant hip arthritis. We recommend that pediatric hip surgery in Hurler syndrome be designed with the possibility of early hip replacement in mind. LEVEL OF EVIDENCE: Level III.

Management of total femoral bone loss using a hybrid cement spacer surgical technique.

Standard treatment for an infected total hip arthroplasty is 2-stage revision. Bone loss in infected total hip arthroplasty presents specific challenges during the first stage. This is especially the case when there is massive or complete loss of the femoral bone stock. We describe a technique successfully used in the setting of total femoral bone loss using a hybrid cement spacer. We describe 2 cases illustrating the technique and perioperative course. This technique is a potential solution for total femoral bone loss that allows the individual to maintain mobility before definitive surgery.

Mitochondrial mutagenesis correlates with the local inflammatory environment in arthritis.

BACKGROUND: To examine the association between mitochondrial mutagenesis and the proinflammatory microenvironment in patients with inflammatory arthritis. METHODS: Fifty patients with inflammatory arthritis underwent arthroscopy and synovial tissue biopsies, synovial fluid and clinical assessment were obtained. Fifteen patients pre/post-TNFi therapy were also recruited. Normal synovial biopsies were obtained from 10 subjects undergoing interventional arthroscopy. Macroscopic synovitis/vascularity was measured by visual analogue scale. Cell-specific markers CD3 (T cells) and CD68 (macrophages) were quantified by immunohistology. TNFα, IL-6, IFNγ and IL-1ß were measured in synovial fluids by MSD multiplex assays. Synovial tissue mitochondrial mutagenesis was quantified using a mitochondrial random mutation capture assay (RMCA). The direct effect of TNFα on oxidative stress and mitochondrial function was assessed in primary cultures of rheumatoid arthritis synovial fibroblast cells (RASFCs). Mitochondrial mutagenesis, reactive oxygen species (ROS), mitochondrial membrane potential (MMP) and mitochondrial mass (MM) were quantified using the RMCA and specific cell fluorescent probes. RESULTS: A significant increase in mtDNA mutation frequency was demonstrated in inflamed synovial tissue compared with control (p<0.05), an effect that was independent of age. mtDNA mutations positively correlated with macroscopic synovitis (r=0.52, p<0.016), vascularity (r=0.54, p<0.01) and with synovial fluid cytokine levels of TNFα (r=0.74, p<0.024) and IFNγ (r=0.72, p<0.039). mtDNA mutation frequency post-TNFi therapy was significantly lower in patients with a DAS<3.2 (p<0.05) and associated with clinical and microscopic measures of disease (p<0.05). In vitro TNFα significantly induced mtDNA mutations, ROS, MM and MMP in RASFCs (all p<0.05). CONCLUSION: High mitochondrial mutations are strongly associated with synovial inflammation showing a direct link between mitochondrial mutations and key proinflammatory pathways.

Can a periarticular levobupivacaine injection reduce postoperative opiate consumption during primary hip arthroplasty?

BACKGROUND: Several reports have confirmed the ability of intraoperative periarticular injections to control pain after THA. However, these studies used differing combinations of analgesic agents and the contribution of each, including the local anesthetic agent, is uncertain. Understanding the independent effects of the various agents could assist in improved pain management after surgery. QUESTIONS/PURPOSES: We therefore determined the ability of intraoperative periarticular infiltration of levobupivacaine to (1) reduce postoperative pain, (2) reduce postoperative morphine requirements, and (3) reduce the incidence of nausea and urinary retention. PATIENTS AND METHODS: A double-blinded, randomized, placebo-controlled trial of patients undergoing primary THAs was performed. Patients were randomized to receive a periarticular infiltration of 150 mg levobupivacaine in 60 mL 0.9% saline (n = 45) or a placebo consisting of 60 mL 0.9% saline (n = 46). We obtained a short-form McGill pain score, visual analog scale (VAS), and morphine requirements via patient-controlled analgesia (PCA) as primary measures. Postoperative antiemetic requirements and need for catheterization for urinary retention were determined as secondary measures. RESULTS: Subjectively reported pain scores and the overall intensity scores were similar for both groups in the postoperative period. At the same time the mean morphine consumption was less in the levobupivacaine group, most notable in the first 12 hours after surgery: treatment group 11.5 mg vs control group 21.2 mg. We observed no differences in the frequency of postoperative nausea and vomiting or urinary retention. CONCLUSIONS: Our observations suggest periarticular injection of levobupivacaine can supplement available postoperative analgesic techniques and reduce postoperative morphine requirements after THA. LEVEL OF EVIDENCE: Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Diagnostic accuracy of magnetic resonance imaging and magnetic resonance arthrography of the hip is dependent on specialist training of the radiologist.

OBJECTIVE: Significant differences between magnetic resonance imaging reports and intraoperative findings at the time of hip arthroscopy were documented in our practice. We sought to examine the accuracy of radiological reporting of hip pathology based on the training level of the reporting radiologist. MATERIALS AND METHODS: A retrospective review of hip arthroscopies carried out between July 2008 and June 2009 identified 61 cases where original MRI scans had been reported by general community radiologists. These scans were then reviewed by musculoskeletal specialist radiologists who were blinded to both the original report and the surgical findings. Accuracy of both subsets of radiologists was compared to arthroscopic findings with regard to labral, acetabular, femoral and impingement lesions. RESULTS: Musculoskeletal radiologists performed better than community radiologists in terms of overall accuracy. Accuracy rates for MSK radiologists were 85, 79, 59, and 82% for labral, acetabular chondrosis, and femoral chondrosis and impingement lesions, respectively. Whereas accuracy rates for community radiologists were 70, 28, 52, and 59% (p values = 0.08, <0.001, 0.59, <0.001). Accuracy was significantly improved for both groups of radiologists when MR arthrograms were reviewed rather than conventional MRIs. CONCLUSIONS: This study establishes the relationship between accuracy of reporting and the training level of the performing radiologists.

The 25 most cited articles in arthroscopic orthopaedic surgery.

PURPOSE: The purpose of this study was to use Web of Knowledge to determine which published arthroscopic surgery-related articles have been cited most frequently by other authors by ranking the 25 most cited articles. We furthermore wished to determine whether there is any difference between a categorical "journal-by-journal" analysis and an "all-database" analysis in arthroscopic surgery and whether such a search methodology would alter the results of previously published lists of "citation classics" in the field. We analyzed the characteristics of these articles to determine what qualities make an article important to this subspecialty of orthopaedic surgery. METHODS: Web of Knowledge was searched on March 7, 2011, using the term "arthroscopy" for citations to articles related to arthroscopy in 61 orthopaedic journals and using the all-database function. Each of the 61 orthopaedic journals was searched separately for arthroscopy-related articles to determine the 25 most cited articles. An all-database search for arthroscopy-related articles was carried out and compared with a journal-by-journal search. Each article was reviewed for basic information including the type of article, authorship, institution, country, publishing journal, and year published. RESULTS: The number of citations ranged from 189 to 567 in a journal-by-journal search and from 214 to 1,869 in an all-database search. The 25 most cited articles on arthroscopic surgery were published in 11 journals: 8 orthopaedic journals and 3 journals from other specialties. The most cited article in arthroscopic orthopaedic surgery was published in The New England Journal of Medicine, which was not previously identified by a journal-by-journal search. CONCLUSIONS: An all-database search in Web of Knowledge gives a more in-depth methodology of determining the true citation ranking of articles. Among the top 25 most cited articles, autologous chondrocyte implantation/transplantation is currently the most cited and most popular topic in arthroscopic orthopaedic surgery and research. CLINICAL RELEVANCE: Analysis of the 25 most cited articles allows us to identify the most popular field of research in arthroscopic orthopaedic surgery and gives us insight into the quality and characteristics that are required for an article to become highly cited.

Analgesic control and functional outcome after knee arthroscopy: results of a randomized double-blinded trial comparing a hyaluronic acid supplement with bupivacaine.

OBJECTIVE: Hyaluronic acid (HA) is a naturally occurring substance within normal synovial joints. Although its efficacy in treating osteoarthritis has been evaluated, it has not been established whether it is of benefit after routine arthroscopic procedures. We hypothesized that immediate supplementation with HA after completion of arthroscopy would result in improved short-term analgesic and functional outcomes after knee arthroscopy. DESIGN: Double-blinded randomized controlled trial. SETTING: Tertiary referral center. PATIENTS: One hundred ten patients presenting for routine arthroscopic procedures were invited to participate in the study. After exclusion criteria were applied, 98 patients were randomized to receive either 10 mL of 0.5% bupivacaine or 3 mL of HA into the joint immediately after completion of surgery. INTERVENTIONS: After completion of surgery, all patients were randomized to receive either 10 mL of 0.5% bupivacaine or 3 mL of HA into the knee joint. MAIN OUTCOME MEASURES: Visual analogue scale (VAS) pain scores were obtained at baseline; 1, 2, and 24 hours; and 1, 2, and 6 weeks after surgery. Western Ontario and McMaster Universities (WOMAC) and Tegner-Lysholm scores were obtained at baseline and then at 1, 2, and 6 weeks after surgery. RESULTS: Forty-nine patients received intra-articular bupivacaine and 49 received HA. There was no statistical difference in any of the outcome measures (VAS pain scores, WOMAC, and Tegner-Lysholm) at any time point between the groups overall. CONCLUSIONS: There was no benefit of HA injection immediately at the end of knee arthroscopy in the first 6 weeks after surgery. CLINICAL RELEVANCE: Routine use of HA at the time of knee arthroscopy cannot be recommended.

Local anaesthetics and chondrotoxicty: What is the evidence?

PURPOSE: Recent reports have suggested that local anaesthetic agents have a toxic effect on articular chondrocytes. This is despite the widespread intra-articular use of local anaesthetic agents following arthroscopic procedures for a number of years. METHODS: We have reviewed the available basic science literature focusing on the studies assessing the effect of exposing articular chondrocytes to local anaesthetic agents. We attempt to highlight the key findings and, where possible, extrapolate the laboratory findings to the operating theatre. RESULTS: Basic science reports are analysed according to their setting of either in vitro, ex vivo or in vivo and according to cell line. A majority of work to date has been done using in vitro models. Only a small number of in vivo models using animal cell lines have been used and the best of these have conflicting results with regard lasting toxicity secondary to local anaesthetic exposure. CONCLUSIONS: Numerous reports suggest a toxic effect of local anaesthetic agents on articular chondrocytes, however, further work is warranted to establish the precise mechanism of toxicity and whether or not single bolus administration results in long-term deleterious outcomes. Determining the ideal in vitro model will help in extrapolating laboratory data to the operating theatre.

A novel in vitro model of ischaemic preconditioning: its effect on cell viability in human skeletal muscle and a possible explanation for the 'second window of protection'.

BACKGROUND: The ischaemia-reperfusion (IR) injury causes significant morbidity. Ischaemic preconditioning (IPC) is a technique for limiting the effects of the IR injury. Its potential has not yet been harnessed in orthopaedics. AIMS: To establish a novel in vitro IR model using a human skeletal muscle cell line. Secondly, to introduce simulated IPC to the model and examine the effect of this on cell viability. METHODS: A human skeletal muscle cell line was cultured in vitro. Placing the cells in a hypoxic buffer and a closed hypoxic environment simulated ischaemia. Reversing this process simulated reperfusion. IPC was simulated by alternate cycles of ischaemia and reperfusion. Cell viability comparisons were made between control and experimental groups of cells. RESULTS: A reproducible in vitro IR model was established. The addition of simulated IPC is associated with increased cell death at 12 and 24 h of reperfusion. Significantly greater cell survival is seen in the IPC group when measured at 72 h reperfusion. CONCLUSIONS: We hypothesise that IPC initially decreases cell number. The remaining cells are more robust. This selected cell line then expands over the course of 72 h and displays greater resistance to the IR injury. This theory can help explain delayed preconditioning.

Total joint arthroplasty in nonagenarians--a retrospective review of complications and resource use.

Increased age brings with it the potential for increased surgical risk. Assessment of specific age cohorts is necessary to plan future service provision and this is the case in hip and knee arthroplasty as the demand for these procedures is anticipated to increase. We retrospectively reviewed the outcomes, including complications, length of stay and blood transfusion rate, in a cohort of 35 nonagenarians undergoing primary or revision total hip and knee arthroplasty. All patients were pre-assessed by anaesthetists before being deemed suitable to undergo surgery in the unit. The mean length of hospital stay was 13.7 +/- 10 days (range 2-56). Thirty-one percent of patients required a blood transfusion. Patients who underwent primary total hip arthroplasty reported improved joint specific functional scores. In this appropriately selected group of nonagenarians, we found no evidence to suggest surgery be withheld on the basis of age alone. However, patients with multiple medical comorbidities warrant appropriate assessment and surgical intervention in an institution with appropriate support. Future planning needs to take into account the predicted increase in demand for arthroplasty surgery in this age group.

Pravastatin suppresses matrix metalloproteinase expression and activity in human articular chondrocytes stimulated by interleukin-1ß.

BACKGROUND: Matrix metalloproteinases are catabolic enzymes that play a key role in the articular cartilage degeneration evident in degenerative and inflammatory conditions of articular cartilage. The aim of this study is to assess the ability of pravastatin to modify matrix metalloproteinase (MMP) messenger RNA (mRNA) expression and enzyme activity in a culture of normal human chondrocytes stimulated by interleukin-1ß. MATERIALS AND METHODS: Normal human chondrocytes were stimulated with interleukin (IL)-1ß for 6 h to induce MMP expression, simulating a catabolic state, and then treated with pravastatin (1, 5 and 10 µM) for a further 18 h before cell lysates and supernatants were harvested. Cells stimulated with IL-1ß but not treated with pravastatin served as controls. Real-time polymerase chain reaction (PCR) was used to assess expression of MMP-3 and MMP-9 mRNA. MMP enzyme activity was assessed using a fluorescent MMP-specific substrate. Statistical analysis was performed using analysis of variance (ANOVA). RESULTS: MMP-3 and MMP-9 mRNA expression was reduced at all concentrations tested with statistically significant trends in reduction (p = 0.002 and <0.001, respectively). Analysis of culture supernatants revealed that pravastatin treatment led to a reduction in total MMP activity but not to a statistically significant degree (p = 0.07). CONCLUSIONS: Treatment with pravastatin of stimulated human chondrocytes leads to significant down-regulation of selected MMP genes and a non-significant reduction in MMP enzyme activity. Our results provide further evidence that statins may have a role to play in future treatment of disease affecting articular chondrocytes.

The role of preoperative cardiac investigation in emergency hip surgery.

BACKGROUND: Given the well recognized imperative to treat hip fractures as expeditiously as possible there can arise uncertainty regarding the balance between pre-operative medical optimization and delay of surgery. Echocardiography is often felt to considerably delay surgery with limited change to patient management. METHODS: We retrospectively reviewed forty-nine consecutive patients who had echocardiography prior to surgery for hip fracture and compared them to fifty-eight patients who did not have echocardiography. RESULTS: We found that those who had echocardiography were more likely to have medication changes (51.02% vs. 6.9%) but were unlikely to require angiography, bypass or valvular surgery prior to fracture fixation. Those undergoing echo had a longer time to surgery-3.30 days (SD=2.49) while those in the control group waited 1.5 days (SD=1.29), (p=0.005). Rates of spinal anaesthesia were similar in both groups. CONCLUSIONS: We feel that these results confirm the theory that echocardiography, as currently provided, significantly delays surgery for hip fracture and that this may negatively affect patient outcomes.

The effect of a new direct Factor Xa inhibitor on human osteoblasts: an in-vitro study comparing the effect of rivaroxaban with enoxaparin.

BACKGROUND: Current treatments for the prevention of thromboembolism include heparin and low-molecular weight heparins (LMWHs). A number of studies have suggested that long term administration of these drugs may adversely affect osteoblasts and therefore, bone metabolism. Xarelto™ (Rivaroxaban) is a new anti-thrombotic drug for the prevention of venous thromboembolism in adult patients undergoing elective hip and knee replacement surgery. The aim of this in vitro study was to investigate the possible effects of rivaroxaban on osteoblast viability, function and gene expression compared to enoxaparin, a commonly used LMWH. METHODS: Primary human osteoblast cultures were treated with varying concentrations of rivaroxaban (0.013, 0.13, 1.3 and 13 µg/ml) or enoxaparin (1, 10 and 100 µg/ml). The effect of each drug on osteoblast function was evaluated by measuring alkaline phosphatase activity. The MTS assay was used to assess the effect of drug treatments on cell proliferation. Changes in osteocalcin, Runx2 and BMP-2 messenger RNA (mRNA) expression following drug treatments were measured by real-time polymerase chain reaction (PCR). RESULTS: Rivaroxaban and enoxaparin treatment did not adversely affect osteoblast viability. However, both drugs caused a significant reduction in osteoblast function, as measured by alkaline phosphatase activity. This reduction in osteoblast function was associated with a reduction in the mRNA expression of the bone marker, osteocalcin, the transcription factor, Runx2, and the osteogenic factor, BMP-2. CONCLUSIONS: These data show that rivaroxaban treatment may negatively affect bone through a reduction in osteoblast function.

Human chondrocyte viability after treatment with local anesthetic and/or magnesium: results from an in vitro study.

PURPOSE: We aimed to assess the effect on chondrocyte viability of adding magnesium to a variety of commonly available local anesthetic agents. METHODS: Human chondrocytes were grown under standard culture conditions. Cells were exposed to a local anesthetic agent with the addition of magnesium (10%, 20%, or 50%). Cells were also exposed to the varying concentrations of magnesium and 0.9% saline solution. Untreated cells served as controls. The CellTiter 96 AQueous One Solution Cell Proliferation Assay was used to assess for cell viability 24 hours after exposure. One-way analysis of variance was used to test for statistical significance. RESULTS: Magnesium sulfate alone was no more toxic than normal saline solution (P > .3) compared with untreated cells. The addition of magnesium to the local anesthetic agents resulted in greater cell viability than when cells were treated with a local anesthetic alone (lidocaine [P = .033], levobupivacaine [P = .007], bupivacaine [P < .001], and ropivacaine [P < .001]). CONCLUSIONS: Our findings support the use of magnesium either alone or in combination with a local anesthetic rather than a local anesthetic alone, and this represents a potential strategy for the reduction of chondrocyte toxicity associated with intra-articular local anesthetic administration after arthroscopy. CLINICAL RELEVANCE: The addition of magnesium to a local anesthetic results in a reduced toxic effect to the articular chondrocyte. This may represent a potential approach to intra-articular analgesia.

Post-operative opiate requirements after hip arthroscopy.

PURPOSE: Although hip arthroscopy continues to evolve in its use and its popularity grows, little attention has been paid to the anaesthetic and analgesic management of patients undergoing this procedure. We aimed to report on our initial experience of the anaesthetic and analgesic requirements of a consecutive series of patients undergoing hip arthroscopy. METHODS: We reviewed the surgical and anaesthetic records of the initial, consecutive 85 patients undergoing hip arthroscopy for any reason at our hospital. Basic demographics, intra-operative findings, operative procedures, analgesic requirements in the form of opiate requirement and post-operative pain scores were reviewed. RESULTS: The mean intra-operative morphine dose was 7.1 mg (S.D. 3.2 mg). Thirty-nine patients (46%) required I.V. morphine at in the recovery room post-arthroscopy (mean 1.8 mg; S.D. 2.6 mg). Regression analysis showed that lower intra-operative opiate dose resulted in higher maximum VAS pain scores (P = 0.03) and rescue intravenous opiate (P < 0.001) requirement post-surgery. CONCLUSIONS: Adequate intra-operative morphine use can minimize post-operative pain and subsequent need for rescue analgesia.

Intra-operative imaging technique to aid safe placement of screws in percutaneous fixation of pelvic and acetabular fractures.

Percutaneous internal fixation of pelvic fractures is becoming increasingly more popular among trauma surgeons worldwide due to reduced surgical related morbidity and facilitation of early mobilisation. Visualisation of the pelvic bony anatomy during percutaneous fixation is difficult, making the procedure technically demanding. We present a simple and easy intra-operative imaging technique that helps to confirm safe positioning of screws, particularly in the narrow anterior acetabular column, by use of radiopaque contrast medium to define the appropriately drilled track.

Transcriptional responses in the adaptation to ischaemia-reperfusion injury: a study of the effect of ischaemic preconditioning in total knee arthroplasty patients.

BACKGROUND: Ischaemic preconditioning (IPC) has emerged as a method of reducing ischaemia-reperfusion injury. However, the complex mechanism through which IPC elicits this protection is not fully understood. The aim of this study was to investigate the genomic response induced by IPC in muscle biopsies taken from the operative leg of total knee arthroplasty patients in order to gain insight into the IPC mechanism. METHODS: Twenty patients, undergoing primary total knee arthroplasty, were randomly assigned to IPC (n = 10) and control (n = 10) groups. Patients in the IPC group received ischaemic preconditioning immediately prior to surgery. IPC was induced by three five-minute cycles of tourniquet insufflation interrupted by five-minute cycles of reperfusion. A muscle biopsy was taken from the operative knee of control and IPC-treated patients at the onset of surgery and, again, at one hour into surgery. The gene expression profile of muscle biopsies was determined using the Affymetrix Human U113 2.0 microarray system and validated using real-time polymerase chain reaction (RT-PCR). Measurements of C-reactive protein (CRP), erythrocyte sedimentation (ESR), white cell count (WCC), cytokines and haemoglobin were also made pre- and post-operatively. RESULTS: Microarray analysis revealed a significant increase in the expression of important oxidative stress defence genes, immediate early response genes and mitochondrial genes. Upregulation of pro-survival genes was also observed and correlated with a downregulation of pro-apoptotic gene expression. CRP, ESR, WCC, cytokine and haemoglobin levels were not significantly different between control and IPC patients. CONCLUSIONS: The findings of this study suggest that IPC of the lower limb in total knee arthroplasty patients induces a protective genomic response, which results in increased expression of immediate early response genes, oxidative stress defence genes and pro-survival genes. These findings indicate that ischaemic preconditioning may be of potential benefit in knee arthroplasty and other musculoskeletal conditions.

Prevalence of Internet use amongst an elective spinal surgery outpatient population.

Nationally 62% of individuals in Ireland have internet access. Previous published work has suggested that internet use is higher among those with low back pain. We aimed to determine the levels of internet access and use amongst an elective spinal outpatient population and determine what characteristics influence these. We distributed a self-designed questionnaire to patients attending elective spinal outpatient clinics. Data including demographics, history of surgery, number of visits, level of satisfaction with previous consultations, access to the internet, possession of health insurance, and details regarding use of the internet to research one's spinal complaint were collected. 213 patients completed the questionnaire. 159 (75%) had access to the internet. Of this group 48 (23%) used the internet to research their spinal condition. Increasing age, higher education level, and possession of health insurance were all significantly associated with access to the internet (p < 0.05). A higher education level predicted greater internet use while possession of insurance weakly predicted non-use (p < 0.05). In our practice, internet access is consistent with national statistics and use is comparable to previous reports. Approximately, one quarter of outpatients will use the internet to research their spinal condition. Should we use this medium to disseminate information we need to be aware some groups may not have access.