Enterococcus faecalis is a rare but recognized cause of prosthetic joint infection. It is notorious for formation of biofilm on prosthetic surfaces. We hypothesized that a ‘serum factor’ was responsible for transformation of E. faecalis from its planktonic form to a biofilm existence upon making contact with prostheses. Using a novel ‘proteomic approach’, we studied the protein expression profiles of this bacterium when grown on an artificial surface in a serum environment against a control.

E.faecalis 628 transconjugant formed by conjugation clinical strain (E55) and laboratory strain (JH2-2) was used to inoculate each of rabbit serum (RS) and Brain Heart Infusion (BHI) agar as a control and grown for 24 hours. Proteins were harvested for analysis in fractions including cell surface, membrane and cytosolic proteins. Recovered proteins were separated using 2-dimentional polyacrylamide gel electrophoresis (2D PAGE). Gels were stained and spots of interest harvested. These were analyzed using MALDI mass spectrometry followed by peptide mass fingerprinting using online database searches.

Two surface exclusion proteins Sea1 and PrgA were only expressed from the serum culture. These proteins are both encoded by genes very close to the gene for enterococcal aggregation substance PrgB, which plays an integral role in biofilm formation. PrgA and PrgB are both encoded by the prgQ operon and hence expressed simultaneously upon activation of the operon.

This tendency for serum only protein expression suggests the possibility of a pheromone-like activator in serum that could be a potential therapeutic target for management of biofilm associated E. faecalis prosthetic infections.

Necrotising Fasciitis is a life threatening rapidly progressing bacterial infection of the skin requiring prompt diagnosis and treatment. Optimum care warrants a combination of antibiotics, surgical debridement and intensive care support. All cases of Necrotising Fasciitis over 10 years in the North East of Scotland were reviewed to investigate trends and learn lessons to improve patient care, with the ultimate aim of developing and implementing new treatment algorithms.

All cases from August 2006-February 2016 were reviewed using a combination of paper based and electronic hospital records. Data including observations, investigations, operative interventions, microbiology and clinical outcomes was reviewed and analysed with pan-specialty input from Microbiology, Infectious Disease, Trauma & Orthopaedics, Plastic Surgery and Intensive Care teams.

36 cases were identified, including 9 intravenous drug abusers. The mean LRINEC Score was 7. Patients were commonly haemodynamically stable upon admission, but deteriorated rapidly. 18/31 of cases were polymicrobial. Streptococcus Pyogenes was the most common organism in monomicrobial cases. 29/36 patients were discharged, 6 patients died acutely, giving an acute mortality rate of 17%. In total 6 amputations or disarticulations were performed from a total of 82 operations carried out on this group, with radical debridement the most common primary operation. The mean time to theatre was 3.54 hours. A grossly elevated admission respiratory rate (50 resp/min) was associated with increased mortality.

Necrotising fasciitis presents subtly, but carries significant morbidity and mortality. A high index suspicion allows timely intervention. We strongly believe that a pan-specialty approach is the cornerstone for good outcomes.

Nasal carriers of methicillin sensitive Staphylococcus aureus (MSSA) have an increased risk for health-care associated infections. There is currently no national screening policy for the detection of MSSA in the UK. This study aimed to: evaluate the diagnostic performance of molecular and culture techniques in MSSA screening, determine the cause of any discrepancy between the diagnostic techniques, and model the potential effect of different diagnostic techniques on MSSA detection in orthopaedic patients. Paired nasal swabs for PCR assay and culture of S. aureus were collected from a study population of 273 orthopaedic outpatients due to undergo joint replacement surgery.

The prevalence of MSSA nasal colonisation was found to be between 22.4–35.6%. The current standard direct culturing methods for detecting S. aureus significantly underestimated the prevalence (p=0.005), failing to identify its presence in ∼1/3 of patients undergoing joint replacement surgery.

Modelling these results to national surveillance data, it was estimated that 800–1200 MSSA surgical site infections could be prevented annually in the UK by using alternative diagnostic methods to direct culture in pre-operative MSSA screening and eradication programmes.

Two-stage revision is the gold standard for managing infected total hip and knee arthroplasties. The aim was to assess the effect of duration between stages on reinfection rate at one year.

A systematic review and meta-analysis was conducted on all studies investigating reinfection rate with documented interval between first and second stages. Total hip (THR) and total knee replacements (TKRs) were included but analysed separately. The effect size of studies was stratified according to sample size then with study quality.

All papers up until November 2015 (including non-English language) were considered. From 3827 papers reviewed, 38 cohorts from 35 studies were included, comprising 23 THR and 15 TKR groups. Average study quality was 5.6/11 (range 3–8). Funnel plots calculated to assess for bias indicated significant asymmetry at lower sample sizes in both groups.

In the TKR group, studies with 0–3 months between stages showed a significantly lower reinfection rate than 3–6 months (9.5% 21/222 vs 20.7% 28/135, p<0.01). A similar trend was seen in the THR group (6.1% vs 10.7%, p<0.05). No difference was observed for either group between 3–6 and 6–9 months.

There is no consensus regarding the appropriate duration between surgeries in two-stage revisions for infection. Studies stratified by sample size and quality indicate an increased reinfection rate past three months. Published guidance is no substitute for clinical decision-making but the conclusions from this study are to recommend against routine delay of more than 3 months between first and second stage revisions for infected THR and TKR.

Kirschner wires are commonly used in paediatric fractures, however, the requirement for removal and the possibility of pin site infection provides opportunity for the development of new techniques that eliminate these drawbacks. Bioabsorbable pins that remain in situ and allow definitive closure of skin at the time of insertion could provide such advantages.

Three concurrent studies were performed to assess the viability of bioabsorbable pins across the growth plate. (1) An epidemiological study to identify Kirschner wire infection rates. (2) A mechanical assessment of a bioabsorbable pin compared to Kirschner wires in a simulated supracondylar fracture. (3) The insertion of the implants across the physis of sheep to assess effects of the bioabsorbable implant on the growth plate via macroscopic, pathohistological and micro-CT analysis.

An infection rate of 8.4% was found, with a deep infection rate of 0.4%. Mechanically the pins demonstrated comparable resistance to extension forces (p=) but slightly inferior resistance to rotation (p=). The in vivo component showed that at 6 months: there was no leg length discrepancy (p=0.6), with micro-CT evidence of normal physeal growth without tethering, and comparable physeal width (p=0.3).

These studies combine to suggest that bioabsorbable pins do not represent a threat to the growth plate and may be considered for physeal fracture fixation.

Following the neonatal examination the 6–8 week ‘GP check’ forms the second part of selective surveillance for developmental dysplasia of the hip (DDH) in the UK. We aim to investigate the effectiveness of this 6–8 week examination for DDH.

This is a observational study including all infants born in our region over 5 years. Early presentation was defined as diagnosis within 14 weeks of birth and late presentation after 14 weeks. Treatment record for early and late DDH as well as referrals for ultrasound (US) following the 6–8 week check were analysed. The attendance at the 6–8 week examination in those patients who went on to present with a late DDH was also analysed.

23112 live births, there were 141 confirmed cases of DDH. 400 referrals for ultrasound were received from GP; 6 of these had a positive finding of DDH. 27 patients presented after 14 weeks and were classified as late presentations. 25 of these patients had attended the 6–8 week examination and no abnormality had been identified. The sensitivity of the examination was 19.4%, its specificity was 98% and it had a positive predictive value of 1.5%

For many years the 6–8 week ‘check’ has been thought of as a safety net for those children with DDH not identified as neonates, however we found that 4 out of every 5 children with DDH were not identified. It is essential efforts are made to impove detection as the long term consequences of late presentation can be life changing.

Carpal tunnel syndrome (CTS) is the most common peripheral mononeuropathy seen in clinical practice. Approximately 34% of CTS patients undergo carpal tunnel decompression (CTD) surgery, in the UK. We investigated the change in epidemiology of CTD based on sex, age, socio-economic deprivation and geographical location, in Scotland, over the last 20 years.

76,076 CTD were performed between 1996–2015 (71% female, M:F ratio 1:2.4). The overall incidence rate of CTD was 73/100,000 person years. The mean age was 50–59 years old for both sexes. Socio-economic deprivation was associated with higher incidence rates of CTD (most deprived 89/100,000 person years and least deprived 64/100,000 person years) (p<0.01). NHS health boards with low populations and a more rural location had higher incidence rates; mean 98/100,000 person years (range 4–238/100,000 person years) compared to high population heath boards in urban locations; mean 74/100,000 person years (range 4–149/100,000 person years) (p<0.01). There has been a significant increase in number and overall incidence of CTD, in Scotland, during the study period: in 1996, 1,156 CTD performed (incidence 23/100,000 person years) vs. 2015, 5,292 CTD performed (incidence 87/100,000 person years) (p<0.01).

We conclude that middle aged females are still the most common demographic undergoing CTD but the incidence rate is increasing over time. There appears to be an association between CTD and socio-economic deprivation. The incidence of CTD, and change over time, differs between health boards.

Simulation in surgical training has become a key component of surgical training curricula, mandated by the GMC, however commercial tools are often expensive. As training budgets become increasingly pressurised, low-cost innovative simulation tools become desirable. We present the results of a low-cost, high-fidelity simulator developed in-house for teaching fluoroscopic guidewire insertion.

A guidewire is placed in a 3d-printed plastic bone using simulated fluoroscopy. Custom software enables two inexpensive web cameras and an infra-red led marker to function as an accurate computer navigation system. This enables high quality simulated fluoroscopic images to be generated from the original CT scan from which the bone model is derived and measured guidewire position. Data including time taken, number of simulated radiographs required and final measurements such as tip apex distance (TAD) are collected.

The simulator was validated using a DHS model and integrated assessment tool. TAD improved from 16.8mm to 6.6mm (p=0.001, n=9) in inexperienced trainees, and time taken from 4:25s to 2m59s (p=0.011). A control group of experienced surgeons showed no improvement but better starting points in TAD, time taken and number of radiographs.

We have also simulated cannulated hip screws, femoral nail entry point and SUFE, but the system has potential for simulating any procedure requiring fluoroscopic guidewire placement e.g. pedicle screws or pelvic fixation. The low cost and 3D-printable nature have enabled multiple copies to be built. The software is open source allowing replication by any interested party. The simulator has been incorporated successfully into a higher orthopaedic surgical training program.

‘Primum non nocere’ is one of the most well known moral principles associated with the medical profession. Often, in our bid to maintain and improve quality of life, we neglect to recognise those patients who are in fact nearing the end of theirs. Thus, our aim was to ascertain if we are recognising the ‘dying’ orthopaedic patient and whether key elements of management in accordance with SIGN are being addressed.

All hip-fracture deaths occurring at a District General Hospital over a 4-year period (2012–2015) were included. Paper and electronic notes were used to record patient demographics, days from admission to death, diagnosis of ‘dying’ and discussions regarding DNACPR and ceiling of care. Total numbers of investigations undertaken during the week prior to death were noted.

89 hip-fracture deaths occurred between 2012–2015, of which 57 were female with a mean age at death of 84 years. The number of days post-admission to death was 17.5 (range 0–109). 45 patients had a new DNACPR recorded and 13 were longstanding. 43 patients (48.3%) were diagnosed as dying at a mean of 7.2 days following admission, 31 of whom (72.1%) had ceiling of care discussed. Of this cohort, 32 had futile investigations during their last week of life and astoundingly 10 on the day of death.

Although some effort is being made to recognise the ‘dying’ orthopaedic patient, further work is needed to establish a clear ceiling of care pathway, which maintains and respects patient comfort and dignity during their last days of life.

Tranexamic Acid (TXA) is widely used to decrease bleeding by its antifibrinolytic mechanism. Its use is widespread within orthopaedic surgery, with level one evidence for its efficacy in total hip and knee replacement surgery; significantly reducing transfusion rates without increased thromboembolic disease. There is limited evidence for its use during hip fracture surgery, and we therefore sought to investigate its effects with a prospective cohort study.

We recorded intra-operative blood loss, pre and post-operative haemoglobin and creatinine levels, post-operative complications and mortality in all hip fracture patients over a six month period. During this time, we introduced one gram of TXA into our standardised hip fracture theatre checklist. It was subsequently given to all patients unless contra-indicated.

A total of 99 patients were included. 90-day mortality in the control group was 16%, there was no mortality in the TXA group (p<0.05). 14 patients required a transfusion in the control group and 3 in the TXA group (19% vs 11% transfusion rate, 0.36 units RCC vs 0.22 per patient respectively) Mean blood loss was 338 vs 235mls, Haemoglobin drop 23 vs 18g/dl control and TXA groups respectively.

We have demonstrated a significantly lower mortality rate with TXA. We have also shown lower rates of transfusion, blood loss and recorded haemoglobin drop with the use of TXA. We intend to continue this study to demonstrate this significantly, and fully clarify the safety profile of TXA in this frail cohort of patients.

Increasing demands on our emergency department (ED) has resulted in the reduction of manipulations (MUAs) at the ‘front door’. We hypothesised that MUAs undertaken in theatre is rising with adverse financial implications. We performed a retrospective audit of operating lists in our institution from 2013–2016. Cost estimates were determined by our finance department. We used the NICE guidelines on management of non-complex fractures (NG38 Feb2016) as our audit standard.

Data on 1372 cases performed over a three-month representative period during 2013–2016 was analysed. MUAs were 13% of the total theatre workload, with an annual increase in volume noted. Additionally, simple displaced distal radius fractures were routinely receiving a MUA (with or without K-wires) as a primary procedure in theatre. When this workload is combined it makes up 22% of the total theatre workload. Average theatre time was 57 minutes per case. Delays to definite procedure ranged from 8 to 120 hours. Cost of hospital admission and theatre utilisation was approximately £1000 per patient. Conversely, the cost of a MUA in the ED was estimated at £150. Given that we currently undertake around 15 manipulations in theatre a month, performing such work in the ED it would save approximately £153,000 a year to our health board.

This audit identifies that MUAs of common orthopaedic injuries undertaken in theatre can lead too significant clinical and financial costs. We have proposed a strong financial argument to management for a twice weekly ‘manipulation list’ in the ED which is currently under review.

The Low Contact Stress (LCS) mobile-bearing total knee replacement (TKR) was designed to minimize polyethylene wear, aseptic loosening and osteolysis. However, registry data suggests there is a significantly greater revision rate associated with the LCS TKR.

The primary aim of this study was to assess long-term survivorship of the LCS implant. Secondary aims were to assess survival according to mechanism of failure and identify predictors of revision.

We retrospectively identified 1091 LCS TKRs that were performed between 1993 and 2006. There was incomplete data available 33 who were excluded. The mean age of the cohort was 69 (SD 9.2) years and there were 577 TKRs performed in females and 481 in males. Mean follow up was 14 years (SD 4.3).

There were 59 revisions during the study period: 14 for infection, 18 for instability, and 27 for polyethylene wear. 392 patients died during follow up. All cause survival at 10-year was 95% (95%CI 91.7–98.3) and at 15-year was 93% (95%CI 88.6–97.8). Survival at 10-years according to mechanism of failure was: infection 99% (95%CI 94–100%), instability 98% (95%CI 94–100%), and polyethylene wear 98% (95%CI92–100). Of the 27 with polyethylene wear only 19 had associated osteolysis requiring component revision, the other 8 had simple polyethylene exchanges. Cox regression analysis, adjusting for confounding variables, identified younger age was the only predictor of revision (hazard ratio 0.96, 95%CI 0.94–0.99, p=0.003).

The LCS TKR demonstrates excellent long-term survivorship with a low rate of revision for osteolysis, however the risk is increased in younger patients.

Proliferation of synovial Mesenchymal Stromal/Stem Cells (MSCs) leads to synovial hyperplasia (SH) following Joint Surface Injury (JSI). Uncontrolled Yap activity causes tissue overgrowth due to modulation of MSC proliferation. We hypothesised that YAP plays a role in SH following JSI.

A spatiotemporal analysis of Yap expression was performed using the JSI model in C57Bl/6 mice. Synovial samples from patients were similarly analysed. Gdf5-Cre;Yap1fl/fl;Tom mice were created to determine the effect YAP1 knockout in Gdf5 lineage cells on SH after JSI.

In patients, Yap expression was upregulated in activated synovium, including a subset of CD55 positive fibroblast-like synoviocytes in the synovial lining (SL). Cells staining positive for the proliferation marker Ki67 expressed active YAP.

In mice, Yap was highly expressed in injured knee joint synovium compared to controls. Yap mRNA levels at 2 (p<0.05) and 8 days (p<0.001) after injury were increased.

Conditional Yap1 knockout in Gdf5 progeny cells prevented hyperplasia of synovial lining (SL) after JSI. Cellularity was significantly decreased in the SL but not in the sub-lining of injured Yap1 knockout- compared to control mice. The percentage of cells in synovium that were Tom+ increased in response to JSI in control and haplo-insufficient but not in YAP1 knockout mice (p<0.05).

Modulation of YAP and proliferation of MSCs in the synovium after JSI provides a system to study the role of SH after trauma in re-establishing joint homeostasis and is a potential novel therapeutic target for the treatment of post traumatic OA.