Aims. The evidence demonstrating the superiority of early MRI has led to increased use of MRI in clinical pathways for acute wrist trauma. The aim of this study was to describe the radiological characteristics and the inter-observer reliability of a new MRI based classification system for scaphoid injuries in a consecutive series of patients. Methods. We identified 80 consecutive patients with acute scaphoid injuries at one centre who had presented within four weeks of injury. The radiographs and MRI scans were assessed by four observers, two radiologists, and two hand surgeons, using both pre-existing classifications and a new MRI based classification tool, the Oxford Scaphoid MRI Assessment Rating Tool (OxSMART). The OxSMART was used to categorize scaphoid injuries into three grades: contusion (grade 1); unicortical fracture (grade 2); and complete bicortical fracture (grade 3). Results. In total there were 13 grade 1 injuries, 11 grade 2 injuries, and 56 grade 3 injuries in the 80 consecutive patients. The inter-observer reliability of the OxSMART was substantial (Kappa = 0.711). The inter-observer reliability of detecting an obvious fracture was moderate for radiographs (Kappa = 0.436) and MRI (Kappa = 0.543). Only 52% (29 of 56) of the grade 3 injuries were detected on plain radiographs. There were two complications of delayed union, both of which occurred in patients with grade 3 injuries, who were promptly treated with cast immobilization. There were no complications in the patients with grade 1 and 2 injuries and the majority of these patients were treated with early mobilization as pain allowed. Conclusion. This MRI based classification tool, the OxSMART, is reliable and clinically useful in managing patients with acute scaphoid injuries. Cite this article: Bone Jt Open 2022;3(11):913–920

Acute Kidney Injury (AKI) formerly known as “acute renal failure” results in rapid reduction in kidney function associated with a failure to maintain fluid, electrolyte and acid-base homeostasis. The UK NCEPOD published a report in 2010 on AKI that revealed many deficiencies in the care of patients with AKI. The UK Renal Association has published the final draft of Clinical Practice Guidelines for Acute Kidney Injury on the 08/01/2011. In our study we determined retrospectively the occurrence of this problem in a District General Hospital and its impact on recovery after lower limb arthroplasty. Data was collected retrospective study over 3 months between Oct to Dec 2010 from theatre registers and the hospital database system. 359 patients were identified. Preoperative (baseline) and postoperative blood investigations included Creatinine, Urea, K+, Na+, GFR, Haemoglobin were analysed. Data collection also included type of anaesthesia, timing of operation, duration of procedure and estimated blood loss. From the hospital database system and clinic letters we collected length of stay and time required for blood results to come back to baseline. A diagnosis of Acute Kidney Injury was based on the International Kidney Disease Improving Global Outcomes (KDIGO) staging classification as recently recommended by UK Renal Association. Stage I Creatinine increase by ≥ 26 μmol/L from baseline, Stage II Creatinine increase by 200-300% and Stage III Creatinine increase ≥ 300%. In our study 11.97% (43/359) of patients developed acute kidney injury following lower limb Arthroplasty. 18 patients (42%) developed Stage I (Cre increase ≥ 26 μmol/L), 17(39%) developed Stage II (Cre increase 200-300%) and 8 patients (19%) developed Stage III (Cre increase ≥ 300%) AKI. Most of these patients were operated during the afternoon session. Patients with acute kidney injury stayed longer in hospital (11.7days) compared to similar age group of patients (6.35days) admitted during the same period. 25% of patients took more than a month for renal parameters to come down to normal. AKI is a new definition and the incidence in our hospital is higher than the 1% expected nationally. Patients with AKI are often complex to treat and specialist timely referral and transfer to renal services if appropriate should be considered. The etiology of Acute Renal Injury is very complex and includes gentamicin antibiotic prophylactic, rapid blood loss in elderly frail patients, non-steroidal pain killers and preexisting cardiac and renal pathology. The need for careful postoperative observation cannot be overemphasised together with judicious blood replacement as required. Acute Kidney Injury following lower limb arthroplasty is a sensitive marker of postoperative care. A successful surgical outcome may not mean a successful renal outcome. Patients with AKI are often complex to treat the new AKI definition and staging system allows an earlier detection and management of this condition. Further prospective audit with large number of patients are required

Abstract. Introduction. Acute kidney injury (AKI) is a common post-operative complication which, in turn, significantly increases risk of other post-operative complications and mortality. This quality improvement project (QIP) aimed to evaluate and implement measures to decrease the incidence of AKI in post-operative Trauma and Orthopaedics (T&O) patients. Methods. Three data collection cycles were conducted using all T&O patients admitted to a single UK West Midlands NHS trust across three six-month periods between December 2018 and December 2020 (n=8215). Patients developing a post-operative AKI were identified using the Acute Kidney Injury Network criteria. Data was collected for these patients including demographic details and AKI risk factors such as ASA grade, hypovolaemia and use of nephrotoxic medications. Results. The percentage of post-operative AKI decreased from 2% (71 patients from 5899 operations) in the first cycles to 1.5% (19 from 1273 operations) by the final cycle. There was a high prevalence of modifiable risk factors for AKI, including post-operative hypovolaemia (50%) and use of nephrotoxic aminoglycosides (81%). Measures implemented between cycles included a pre-operative medication review identifying nephrotoxic medications, early post-operative assessment for consideration of intravenous fluids and junior doctor teaching on fluid therapy. There was a substantial decrease in use of multiple nephrotoxic medications (98% to 59%) and in use of aminoglycosides (88% to 42%) between the final cycles which may explain the reduction in observed AKI incidence. Conclusion. This QIP highlights the benefits of a multifaceted approach in the peri-operative period, through targeting of risk factors in preventing post-operative AKI

Aims. This study aimed to assess the risk of acute kidney injury (AKI) associated with combined intravenous (IV) and topical antibiotic therapy in patients undergoing treatment for periprosthetic joint infections (PJIs) following total knee arthroplasty (TKA), utilizing the Kidney Disease: Improving Global Outcomes (KDIGO) criteria for classification. Methods. We conducted a retrospective analysis of 162 knees (162 patients) that received treatment for PJI post-TKA with combined IV and topical antibiotic infusions at a single academic hospital from 1 January 2010 to 31 December 2022. The incidence of AKI was evaluated using the KDIGO criteria, focussing on the identification of significant predictors and the temporal pattern of AKI development. Results. AKI was identified in 9.26% (15/162) of the cohort, predominantly presenting as stage 1 AKI, which was transient in nature and resolved prior to discharge. The analysis highlighted moderate anaemia and lower baseline serum creatinine levels as significant predictors for the development of AKI. Notably, the study found no instances of severe complications such as wound dehiscence, skin erosion, or the need for haemodialysis following treatment. Conclusion. The findings suggest that the combined use of IV and topical antibiotic therapy in the management of PJIs post-TKA is associated with a low incidence of primarily transient stage 1 AKI. This indicates a potentially favourable renal safety profile, advocating for further research to confirm these outcomes and potentially influence treatment protocols in PJI management. Cite this article: Bone Joint Res 2024;13(10):525–534

MRI is increasingly used in acute wrist injuries but limited information exists regarding the impact on injury management. The aim of this study is to review the injury patterns, including scaphoid injuries and the impact on management and outcome when using MRI in the acute setting. We analysed the injury patterns presenting after an acute wrist injury where a scaphoid fracture might be suspected and a plain x-ray was normal. We assessed the true incidence of scaphoid fractures in this setting and the pattern of other injuries when investigated by early MRI. All acute injuries referred for an MRI from August 2004 to August 2007 were screened. The scans were done on average 6 days post injury (range 1–21 days). These were analysed and the films reviewed including a review of the medical records for injury, subsequent treatment details and outcome. Over a three year period a total of 218 patients were referred for a wrist MRI. Of these 110 (50.4%) were for suspected fractures of the scaphoid and 89 (81%) had a scaphoid MRI series done involving T1 and T2 fat saturated sequences with a scan time of five minutes. The remainder had a full six-sequence wrist MRI, with a scan time of 25 minutes. Overall the positive scaphoid fracture rate was 24% with mainly un-displaced waist fractures identified. The scans were completely normal in 33% removing the need for any further intervention. In 10% bone contusion was identified and a splint was provided for comfort. Of the associated injuries, 33% had associated fractures in the radius, ulna styloid, other carpal or metacarpal bones. In 12% an acute ligament injury was identified with scapho-lunate injury the most common in 8 cases. Additional bone contusion was seen in 20% of patients with an occult fracture. In 76% of wrist injuries with a normal x-ray, an MRI of the wrist lead to a change in the management plan. MRI use has significant positive socio-economic implications for the mainly younger working patients that present with these injuries, with a projected saving of over $80,000 over the period. It is an excellent second line investigation that provides clinically relevant information and can be performed on the day of injury

Acute Kidney Injury (AKI) is an increasingly prevalent complication of lower limb arthroplasty (LLA). Even a transient decrease in kidney function has been shown to be associated with increased mortality and development of subsequent Chronic Kidney Disease (CKD). We set out to determine which perioperative factors are associated with AKI development at our institution through a retrospective cohort methodology. Patients who underwent primary elective LLA from 01/10/16 to 31/09/17 were included, with relevant perioperative data collected from electronic patient records. AKI was classified according to the Acute Kidney Injury Network (AKIN) criteria. Overall 6.6% of 686 patients developed an AKI post-operatively. These individuals had a significantly longer length of stay (Median 7 days vs 5 days for no AKI [p<0.001]). Independent predictors of AKI on multivariate regression analysis included: Diabetes (OR 3.10, 95% CI 1.34 to 7.20; p=0.008) CKD (OR 5.07, 95% CI 2.60 to 9.86; p=<0.001) and male sex (OR female sex 0.33, 95% CI 0.17 to 0.63; p=0.001). A model including any of these three risk factors predicted 82.2% of patients with an AKI. The overall AKI rate for this model was 11.2% compared to 2.3% for those without any of the three criteria. Only 11% of patients had IV fluid continued beyond the recovery room. AKI is a significant problem in LLA. Knowledge of associated risk factors will allow for targeted interventions to decrease AKI incidence. Continuation of IV fluids until the first post-operative morning for high risk individuals may be a simple method of reducing AKI

Aims. There is increasing evidence to support the use of topical antibiotics to prevent surgical site infections. Although previous research suggests a minimal nephrotoxic risk with a single dose of vancomycin powder, fracture patients often require multiple procedures and receive additional doses of topical antibiotics. We aimed to determine if cumulative doses of intrawound vancomycin or tobramycin powder for infection prophylaxis increased the risk of drug-induced acute kidney injury (AKI) among fracture patients. Methods. This cohort study was a secondary analysis of single-centre Program of Randomized Trials to Evaluate Pre-operative Antiseptic Skin Solutions in Orthopaedic Trauma (PREP-IT) trial data. We included patients with a surgically treated appendicular fracture. The primary outcome was drug-induced AKI. The odds of AKI per gram of vancomycin or tobramycin powder were calculated using Bayesian regression models, which adjusted for measured confounders and accounted for the interactive effects of vancomycin and tobramycin. Results. Of the 782 included patients (mean age 48 years (SD 20); 59% male), 83% (n = 648) received at least one vancomycin dose (cumulative range 1 to 12 g). Overall, 45% of the sample received at least one tobramycin dose (cumulative range 1.2 to 9.6 g). Drug-induced AKI occurred in ten patients (1.2%). No association was found between the cumulative dose of vancomycin and drug-induced AKI (odds ratio (OR) 1.08 (95% credible interval (CrI) 0.52 to 2.14)). Additional doses of tobramycin were associated with a three-fold increase in the adjusted odds of drug-induced AKI (OR 3.66 (95% CrI 1.71 to 8.49)). Specifically, the risk of drug-induced AKI rose substantially after 4.8 g of tobramycin powder (7.5% (95% CrI 1.0 to 35.3)). Conclusion. Cumulative doses of vancomycin were not associated with an increased risk of drug-induced AKI among fracture patients. While the risk of drug-induced AKI remains less than 4% with three or fewer 1.2 g tobramycin doses, the estimated risk increases substantially to 8% after four cumulative doses. Level of evidence: Therapeutic Level III. Cite this article: Bone Jt Open 2022;3(4):284–290

BACKGROUND. High-dose antibiotic cement spacers are commonly used to treat prosthetic joint infections following knee arthroplasties. Several clinical studies have shown a high success rate with antibiotic cement spacers, however there is little data on the systemic complications of high-dose antibiotic spacers, particularly acute kidney injury (AKI). This study aims to determine the incidence of AKI and identify risk factors predisposing patients undergoing staged revision arthroplasty with antibiotic cement spacers. METHODS. A single-institution, retrospective review was used to collect and analyze clinical and demographic data for patients who underwent staged revision total knee arthroplasty with placement of an antibiotic-impregnated cement spacer from 2006 to 2016. A search was made through specific procedure (DRG) and diagnostic (CD) codes. Baseline descriptive data were collected for all patients including age, sex, medical comorbidities, type and quantity of antibiotics used in the cement spacer, pre- and postoperative hemoglobin (Hg), BMI, smoking status, peak creatinine levels, and random vancomycin levels. Acute kidney injury was defined as a more than 50% rise in serum creatinine from a preoperative baseline within 90 days postoperatively. RESULTS. A total of 54 staged revision TKA surgeries performed by 5 different surgeons between 2006 and 2016. The total incidence of AKI was 31% (n=17). There was a significant positive association between change in creatinine level and use of oral/intravenous antibiotics (p=0.03, Spearman's rho=0.33) and a significant positive association between AKI and the use of tobramycin cement (p=0.01, Spearman's rho=0.38). Factors that were not significantly associated with AKI include presence of preexisting hypertension (p = 0.26), hyperlipidemia (p = 0.83), coronary artery disease (p = 0.86), chronic kidney disease (p=0.56), and smoking status (p=.35). There was a trend towards increased risk of AKI in patients with diabetes mellitus (p= 0.12), however this was not significant. CONCLUSION. In single staged revision knee arthroplasty there is a significant association between acute kidney injury and type of oral/intravenous antibiotic used in the treatment. Both the use of intravenous vancomycin and tobramycin cement are independently associated with higher rates of AKI. Preexisting medical comorbidities are not independent risk factors for development of AKI. Serum creatinine and measurement of serum aminoglycoside and vancomycin levels should be performed after placement of an aminoglycoside-containing antibiotic cement spacer in a staged revision arthroplasty

Objectives

As per NICE guidance, one of the cornerstones of management of AKI is risk assessment. Aim of the audit is to identify the potential risk factors for postoperative AKI in hip fracture patients.

Whilst the SIGN Guidelines state that the use of prophylactic antibiotics in surgery unequivocally reduces major morbidity, reduces hospital costs and is likely to decrease overall consumption of antibiotics they state the chosen antibiotics must reflect local, disease-specific information about the common pathogens and their antimicrobial susceptibility. Growing healthcare concern regarding the rates of Clostridium Difficile (C. Diff) within the hospital setting have led to rationalised and better streamlined prescribing practice within the NHS. In NHS Lanarkshire this led to revised guidelines for prophylactic antibiotic use in Orthopaedics in 2010. Routine use of 3. rd. generation Cephalosporin has been replaced by Flucloxacillin 1g and Gentamicin 1mg/kg. Anecdotally the surgeons within our department were concerned that they were recognising more post-operative renal impairment than before 2010. Our study took 902 consecutive cases treated surgically with either Total Hip Replacement, Total Knee Replacement, Dynamic Hip Screw for fracture and Hemiarthroplasty for fracture since the introduction of the new antibiotic policy. We compared this with a similar number of cases treated with the same operations pre-2010. We looked at the pre admission Urea & Electrolystes compared with immediate post-operative results and applied the definition of Acute Kidney Injury (AKI) as defined by the Acute Kidney Injury Network. A. A rapid time course (less than 48 hours) and B. Reduction of kidney function either as an absolute increase in serum creatinine of ≥26.4μmol/l (≥0.3 mg/dl) or a percentage increase in serum creatinine of ≥50%. Based on this definition we found an increased rate of AKI of 13.7% after the introduction of the use of Gentamicin from 9.8% before its routine use. We wish to highlight that the routine widespread use of Gentamicin may be increasing the rate of acute renal dysfunction seen in Orthopaedic patients undergoing major surgery

Background. Polytrauma patients are at high risk of systematic inflammatory response syndrome (SIRS) due to an exaggerated unbalanced immune response that can lead to multiple organ failure and increased mortality. This response is often heightened following acute surgical management as a result, damage-control orthopaedics (DCO) was born. This allows the patient to be stabilised using external fixation allowing physiology to improve. This systematic review aims to compare DCO against early total care (ETC) (<24hrs intramedullary nailing) in polytraumatised patients with femoral shaft fractures using a diagnosis of acute lung injury (ALI) as the primary outcome measure. Method. A systematic review of MEDLINE, EMBASE, CENTRAL and AMED was carried out to identify all English language studies comparing ETC versus DCO using ALI as the primary outcome measure. Two authors independently screened the studies and performed data extraction. Risk of bias was assessed using the Cochrane risk of bias tool and the Risk-of-Bias Assessment Tool for Non-randomised Studies. Results. Three studies were selected for final inclusion. One multicentre RCT demonstrated a significantly higher odds ratio (6.69) of ALI in the subgroup receiving ETC compared to DCO. The two other studies were retrospective case series with one reporting no significant difference and the second study reporting a significant reduction in ARDS when a DCO approach was used (7.8% vs 15.1%). Meta-analysis was not possible due to heterogeneity. Conclusions. This review supports evidence that in the more unstable patients (Injury Severity Score≥30) treated surgically for femoral shaft fractures in the first 24 hours, DCO may have a protective effect over ETC for ALI. However further studies with large sample sizes are needed to provide clarity on the subject area. Level of Evidence. 1. Ethics. No approval required given the nature of this study (systematic review)

Background. Post-operative acute kidney injury is significant complication following surgery. Patients who develop AKI have an increased risk for progression into chronic kidney disease, end-stage renal failure and increased mortality risk. The patient outcomes following total knee replacement (TKR), who develop AKI has been a topic of interest in recent years as it may have patient and medicolegal implications. Nevertheless, there are no studies looking at the incidence, risk factors and outcomes of AKI following bilateral TKRs at the same sitting. Objectives. To determine the incidence, risk factors and outcomes of post-operative AKI following bilateral TKRs surgery at the same sitting. Methods. This was a retrospective single-centre study performed at the Princess Royal Hospital, which performed a total of 25 BTKR. The incidence, Surgical and patient risk factors were recorded and analysed. Results. The incidence of AKI as defined by NICE guidelines following bilateral TKRs was 20%. 16% (4 patients) had stage 1 and 4% (1 patient) had stage 2 AKI. The mean change in Creatinine between pre- and post-operative blood tests was +19μmol/L. There was a strong significant correlation between CKD and AKI (r=0.75, P<0.05). Furthermore, a moderate correlation was found between higher BMI and pre-operative Charlson index and AKI. AKI did not have an effect on the length of inpatient stay with the mean inpatient length of stay for patients who had an AKI of 10 days compared to 11days for those who did not. All AKIs were resolved within 72 hours. There were no associated mortalities with AKI. Conclusion. The incidence of AKI following bilateral TKR was 20%. Pre-operative chronic kidney disease as well as having a higher BMI were identified as risk factors for developing AKI. Pre-operative CKD optimisation and careful adequate hydration intra-operatively should be considered in these patients. AKI was not associated with an increased length of stay or mortality in our study

Following ischaemia-reperfusion (I-R) tissues undergo a neutrophil mediated oxidant injury. Vitamin C is a water-soluble endogenous anti-oxidant, which has been shown in previous studies to abrogate neutrophil mediated endothelial injury. Our aim was to evaluate Vitamin C supplementation in the prevention of I-R induced acute muscle injury. Sprague-Dawley rats (n-6/group) were randomised into control, I-R and I-R pretreated with Vitamin C (3.3g over 5 days). Cremasteric muscle was isolated on its neuro-vascular pedicle and I-R injury induced by clamping the pedicle for 3 hours, the tissue was subsequently reperfused for 60 minutes. Following reperfusion muscle function was assessed by electrical field stimulation: peak twitch (PTV), maximum tetanus (MTV) and fatigability values were recorded. Tissue neutrophil infiltration was assessed by tissue myeloperoxidase (MPO) activity and tissue oedema by wet:dry ratio (WDR). Ischaemia-reperfusion (I-R) resulted in a significant decrease in muscle function (PTV< MTV) there was no difference in fatigability values between groups. I-R also resulted in a significant increase in neutrophil infiltration (MPO) and tissue oedema (WDR). Pre-treatment with Vitamin C attenuated I-R injury as assessed by these parameters. This data suggests that oral Vitamin C reduce I-R induced acute muscle injury, possibly by attenuating neutrophil mediated tissue injury

Purpose. There are concerns with regard to the physiological effects of reamed intramedullary femoral fracture stabilisation in patients who have received a pulmonary injury. This large animal study used invasive monitoring techniques to obtain sensitive cardiopulmonary measurements and compared the responses to Early Total Care (reamed intramedullary femoral fracture fixation) to Damage Control Orthopaedics (external fixation), after the induction of acute lung injury. We hypothesised a greater cardiopulmonary response to intramedullary fracture fixation. Method. Acute lung injury (PaO2/FiO2 < 200 mmHg) was induced in 12 invasively monitored and terminally anaesthetised male sheep via the infusion of oleic acid into the right atrium. Each animal underwent surgical femoral osteotomy and fixation with either reamed intramedullary (n=6) or external fixation (n=6). Simultaneous haemodynamic and arterial blood-gas measurements were recorded at baseline and at 5, 30 and 60 minutes after fracture stabilisation. Results. The mean (S.E.) PaO2/FiO2 fell significantly (p<0.05) from 359(37) to 107 (23) and 382 (33) to 128 (18) in the externally fixated and intramedullary nailed groups respectively as a result of the acute lung injury. The further combined effect of surgical osteotomy and subsequent fracture fixation produced a mean (+/− S.E.) PaO2/FiO2 of 114 (21) and 113 (12), in the externally fixated and intramedullary nailed groups respectively, immediately after surgery. This was not significantly different either within or between groups. Similarly the pulmonary vascular resistance (PVR) measured at 4.7 (0.9) and 4.2 (0.5) in the externally fixated and intramedullary nailed groups respectively after lung injury changed to 4.9 (0.7) and 4.3 (0.6) after surgical osteotomy and subsequent fracture fixation which, again was not significantly different either within or between groups. No significant difference in either PaO2/FiO2 or PVR was detected at the monitored 5, 30 and 60 minute intervals that followed fracture stabilisation. Conclusion. Against a background of standardised acute lung injury, there appeared to be no further deterioration produced by the method of isolated femoral fracture fixation in two sensitive physiological parameters commonly used by intensive care physicians

INTRO. Two-stage revision arthroplasty for PJI may make use of an antibiotic-loaded cement spacer (ACS), as successful long- term prevention of reinfection have been reported using this technique.[i] However, there is little data on systemic complications of high-dose antibiotic spacers. Acute kidney injury (AKI) is of clinical significance, as the drugs most commonly utilized, vancomycin and aminoglycosides, can be nephrotoxic. We intended to determine the incidence of AKI in patients that underwent staged revision arthroplasty with an ACS, as well as to identify potential predisposing risk factors for the disease. METHODS. Local databases of six different orthopaedic surgeons were retrospectively reviewed for insertion of either a static or articulating antibiotic cement spacer by from 2007–2017. Dose of antibiotic powder implanted, as well as IV antibiotic used, was collected from operative records. Demographics, comorbidities, and preoperative and postoperative creatinine and hemoglobin values were recorded from the EHR. AKI was defined by a more than 50% rise in serum creatinine from preoperative baseline to at least 1.4 mg/dL, as described by Menge et al.[ii] Variables were analyzed for the primary outcome of AKI within the same hospital stay as insertion of the ACS. Categorical variables were analyzed with Chi-Square test, and continuous variables with univariate logistic regression. RESULTS. 75 patients (39 M, 36 F) receiving an ACS were identified, with a mean age of 70.0 (SD=10.6) and a mean BMI of 31.3 (SD=7.3). Incidence of in-hospital AKI was 13.3%. Patients reached AKI at a mean 6.7 days (SD=4.5), during a median length of stay of 13.5 days (IQR=21.8). No significant correlation was found between AKI and the variables of age (p=.430), BMI (p=.569) or gender (p=.181). AKI was also not associated with increased dose of vancomycin (p=.416), tobramycin (p=.440), or gentamycin (p=.846) within the cement spacer, or the comorbidities of hypertension (p=.094), diabetes (p=.146), coronary artery disease (p=1.00) and renal disease (p=.521). However, decreased baseline hemoglobin showed significantly increased risk for AKI (OR=1.67, p =.049), and increased creatinine showed a trend (OR=2.9, p=.059). Percentage of hemoglobin decrease (preoperative to postoperative) did not increase odds for AKI (p=.700). CONCLUSION. The incidence of acute kidney injury in patients that receive antibiotic cement spacers is relatively high when compared to the data reported in primary TKA. ii,[iii]. Our results suggest that patient related risk factors, such as low preoperative hemoglobin, may be involved in the etiology of AKI in this population. Therefore, it may be clinically appropriate to monitor anemic patients for AKI when implanting an ACS

Aims: There are concerns over the physiological effects of intramedullary femoral fracture stabilisation in patients with pulmonary injury. This large animal study used invasive monitoring to obtain sensitive cardiopulmonary measurements and compared the responses of ‘Early Total Care’ (intramedullary fracture fixation) and ‘Damage Control’ (external fixation), after the induction of lung injury. Methods: Acute lung injury (PaO2/FiO2 < 200 mmHg) was induced in 12 invasively monitored and terminally anaesthetised sheep via oleic acid infusion into the right atrium. Each animal underwent surgical femoral osteotomy and fixation with either reamed intramedullary (n=6) or external fixation (n=6). Haemodynamic and arterial blood-gas measurements were recorded at baseline, 5, 30 and 60 minutes after fracture stabilisation. Results: The mean (+/− S.E.) PaO2/FiO2 fell significantly (p< 0.05) from 401 (+/− 39) to 103 (+/− 35) and 425 (+/− 27) to 122 (+/− 21) in the externally fixated and intramedullary nailed groups respectively after acute lung injury. The further combined effect of surgical osteotomy and fracture fixation produced a mean (+/− S.E.) PaO2/FiO2 of 98 (+/− 21) and 114 (+/− 18), in the externally fixated and intramedullary nailed groups immediately after surgery. This was not significantly different within or between groups. Similarly the pulmonary vascular resistance (PVR) measured at 5.8 (+/− 0.8) and 4.8 (+/− 0.7) after lung injury in the externally fixated and intramedullary nailed groups changed to 5.7 (+/− 0.5) and 4.0 (+/− 0.7) after surgical osteotomy and fracture fixation (no significant difference within or between groups). The PaO2/FiO2 or PVR was not significantly different at the monitored 5, 30 and 60 minute intervals after fracture stabilisation. Conclusion: Against a background of standardised acute lung injury, there was no further deterioration produced by the method of isolated femoral fracture fixation in sensitive physiological parameters commonly used during intensive care monitoring

In September 2011 our departmental protocol for peri-operative prophylactic antibiotic administration was altered from cefuroxime to gentamicin/flucloxacillin, in response to reported links between cephalosporin use and Clostridium difficile (C. diff) infection. As both gentamicin and flucloxacillin are known to be nephrotoxic in some patients, we investigated whether the new regimen increases the risk of Acute Kidney Injury (AKI) in patients undergoing elective and trauma hip and knee surgery, classified by severity (AKI Network criteria). The incidence of C. diff was noted. 10 out of 202 (5%) patients receiving cefuroxime (group A) developed AKI, compared with 23 of 210 (11%) patients receiving gentamicin and flucloxacillin (group B) (p=0.012). The severity of the renal injury was higher in the group B patients with 16 sustaining stage II/III AKI, whereas in Group A only one patient sustained a stage II injury and none stage III. The increased AKI rate in group B was observed equally in hip fracture patients and elective hip/knee replacement patients. However, 3 of 80 (4%) patients with hip fractures who received doses of cefuroxime developed C. diff, with none in the other groups (p=0.04). The choice of prophylactic antibiotics depends on a careful assessment of benefits and risks. Our data suggests that whereas hip fracture patients may have benefitted from the protocol change with reduced C. diff incidence, elective hip and knee replacement patients sustained additional harm. Different antibiotic regimens may be appropriate for these two groups

In late 2011 there was a change in antimicrobial policy in orthopaedic surgery to reduce the Clostridium difficile (C. diff) rate, this was inducted top down from government, to PCT, to hospital trust. The previous antimicrobial policy was Cefuroxime, this was changed to Flucloxacillin and Gentimicin. Following this change it was noticed an increased number of patients appeared to suffer from acute kidney injury (AKI). This led us to evaluate the incidence of AKI pre and post antibiotic change and look at the causes behind this. In this retrospective study all patients admitted with fracture neck of femurs were identified from the National Hip Fracture database and data pulled. The degree of AKI was classified according to the validated RIFILE criteria. Evaluation showed 2–4 fold increase in AKI since antibiotic change. Although mortality was decreased in these patients, the incidence of AKI had increased significantly. However, C. difficile has been obliterated by this change. The investigation highlights potential problems with increased rates of AKI amongst NOF patients, since antibiotic change. Flucloxacillin may have significant impact on this patient group. Dose dependent antibiotics will now be given based on weight and eGFR. Further analysis of this new change needs to be evaluated

In 2011 health policy dictated a reduction in iatrogenic infections, such as Clostridium difficile (C. diff), this resulted in local change to antimicrobial policy in orthopaedic surgery. Previous antimicrobial policy was Cefuroxime, this was changed to Flucloxacillin and Gentimicin. Following this change an increased number of patients appeared to suffer from acute kidney injury (AKI). We initially evaluated the incidence of AKI pre and post antibiotic change and found a correlation between the Flucloxacillin and AKI. We then made changes to antibiotic policy to mitigate the increased rates of AKI and proceeded to evaluate the outcomes. In this prospective study all patients admitted with fracture neck of femurs were identified from the National Hip Fracture database and data obtained. The degree of AKI was classified according to the validated RIFILE criteria. Evaluation showed a 4 fold decrease, from 13% to only 3%, in AKI after introduction of the modified antibiotic policy. C.difficile continues to be non-existent since this change. Flucloxacillin obviously had a significant impact on this patient group. However, we have shown that with appropriate changes to antibiotic policy AKI associated morbidity can be significantly reduced. Dose dependent antibiotics will now be given based on weight and eGFR

Matsen in 1975 described Compartment Syndrome (CS) as a condition in which the circulation and function of tissues within a closed space are compromised by increased pressure within that space. Raised intra-compartmental pressures result in progressive venous obstruction, capillary stagnation and microvascular hypoxia. N-acetyl cysteine (NAC) is an anti-oxidant used clinically to reduce liver injury following paracetamol overdose. NAC has been shown previously to reduce lung injury following exposure to endotoxin. Our aim was to evaluate the efficacy of n-acetyl cysteine in the prevention of CS induced acute muscle injury. Sprague-Dawley rats (n=6/group) were randomised into Control, CS and CS pre-treated with N-Acetyl Cysteine (0.5g/kg i.p. 1 hr prior to induction). Cremasteric muscle was isolated on its neuro-vascular pedicle and CS injury was induced by placing the muscle in a specially designed pressure chamber. Arterial blood pressure was measured via a cannula placed in the carotid artery. To induce compartment syndrome chamber pressure was maintained at diastolic-10 mm Hg. After three hours pressure was released stimulating surgical fasciotomy. One hour after decompression muscle function was assessed by electrical field stimulation: peak twitch (PTV) and maximum tetanus (MTV) values were recorded. Tissue oedema was assessed by wet to dry ratio (WDR). Compartment Syndrome (CS) resulted in a significant decrease in muscle function (PTV, MTV). CS also resulted in a significant increase in tissue oedema (WDR). Pre-Treatment with N-Acetyl Cysteine attenuated CS injury as assessed by these parameters. These data show that administration of the anti-oxidant N-Acetyl Cysteine results in significant attenuation of the muscle injury and oedema caused by Compartment Syndrome. This work was supported by a grant from the Cappagh Trust