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

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

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

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

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

It has been reported that the total steroid dose and acute rejection episodes after organ transplantation is one of the risk factors for the development of osteonecrosis of the femoral head (ONFH), and ONFH in steroid-iduced subgroup may progress more aggressively to femoral head collapse requiring total hip arthroplasty. Despite inherent medical co-morbidities of solid organ transplantation patients, most authors recently have reported successful outcomes of THAs in those patients. But there are few comparative studies on the outcome of THAs for ONFH after different organ transplantations. The purpose of this study was to evaluate and compare a single tertiary referral institution's experience of performing primary THAs in kidney transplantation (KT) and liver transplantation (LT) patients with specific focus on the total steroid dose, clinical outcomes, and relationship between ONFH and absence or presence of acute rejection (AR). Between 1999 and 2010, 4,713 patients underwent organ transplantations (1,957 KT and 2,756 LT) and AR was occurred in 969 patients (20.6%) after transplantation. Among these patients, 131 patients (191 hips) underwent THA for ONFH, and they were retrospectively reviewed. In KT groups, there were 57 men and 36 women with a mean age of 43.7 years. In LT groups, there were 26 men and 13 women with a mean age of 50.4 years. We investigated the dose of steroid administration on both groups, the time period from transplantation to THA, Harris hips score (HHS), visual analogue scale (VAS) and complications. The mean follow up period was 8.1 years (range, 5 to 14 years). One-hundred and thirty-one (2.8%) patients [93 KT and 38 LT] underwent THA after transplantation. The total steroid dose after transplantations was significantly higher in KT group (10,420 mg) than that in LT group (4,567 mg), but the total steroid dose in the first 2 weeks after transplantation was significantly higher in LT group (3,478 mg) than that in KT group (2,564 mg). Twenty-three (2.4%) patients (19 KT and 4 LT) who underwent THA had an episode of AR. In LT group, the total steroid dose in AR groups was significantly higher than that in non-AR groups, whereas in KT group, there was no significant difference of the total steroid dose between AR group and non-AR group. The rate of THAs for ONFH was similar in both groups (2.4% in AR group, 2.9% in non-AR group). The mean time period from transplantation to THA was 986 days for KT and 1,649 days for LT patients. Both groups showed satisfactory HHS and VAS at final follow up, revealed no differences between the groups. The rate of THAs for ONFH was three times higher in KT patients than that in LT patients, but it was similar in both AR group and non-AR group. The total steroid dose was also higher in KT patients compared to LT patients. The clinical outcomes of THA were satisfactory with few complications in both KT and LT patients. Therefore, THAs seems to be a good option for the patients with symptomatic steroid-induced ONFH after KT and LT

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

Little is known about the relationship between head-neck corrosion and its effect on the periprosthetic tissues and distant organs of patients hosting well-functioning devices. The purpose of this study was to investigate in postmortem retrieved specimens the degree and type of taper damage, and the corresponding histologic responses in periprosthetic tissues and distant organs. Fifty postmortem THRs (34 primaries, 16 revisions) retrieved after 0.5 to 26 years were analyzed. Forty-three implants had a CoCrMo stem and seven had a Ti6Al4V stem. All heads were CoCrMo and articulated against polyethylene cups (19 XLPE, 31 UHMWPE). H&E sections of joint pseudocapsules, liver, spleen, kidneys and lymph nodes were graded 1–4 for the intensity of various inflammatory cell infiltrates and tissue characteristics. Corrosion damage of the taper surfaces was assessed using visual scoring and quantitated with an optical coordinate measuring machine. SEM analysis was used to determine the acting corrosion mode. Polyethylene wear was assessed optically. The majority of tapers had minimal to mild damage characterized by local plastic deformation of machining line peaks. Imprinting of the stem topography onto the head taper surface was observed in 18 cases. Column damage on the head taper surface occurred in three cases. All taper surfaces scored moderate or severe exhibited local damage features of fretting and/or pitting corrosion. Moderate or severe corrosion of the head and/or trunnion was present in nine hips. In one asymptomatic patient with bilateral hips, lymphocyte-dominated tissue reactions involving perivascular infiltrates of lymphocytes and plasmacytes were observed. In this patient, mild, focal lymphocytic infiltrates were also present in the liver and kidneys, and there was focal histiocytosis and necrosis of the para-aortic lymph nodes. These two implants, which had been in place for 58.6 and 60.1 months, had severe intergranular corrosion of the CoCrMo trunnion, and column damage and imprinting on the head taper. In the other 41 hips, macrophage responses in the joint pseudocapsule to metallic and/or polyethylene wear particles ranged widely from minimal to marked. Focal necrosis in the pseudocapsules of 12 arthroplasties was related to high concentrations of CoCrMo, TiAl4V, TiO, BaSO4 and polyethylene wear particles. High concentrations of these particles were also detected in para-aortic lymph nodes. Rare to mild macrophages were observed in liver and spleen. This is a comprehensive study of wear and corrosion within well-functioning postmortem retrieved THRs, and the resulting local and distant tissue reactions. One of eight patients with moderate or severe corrosion did have a subclinical inflammatory response dominated by lymphocytes after five years. To what extent such an inflammatory process might progress to become symptomatic is not known. Ionic and particulate products generated by corrosion disseminated systemically. The minor lymphocytic infiltrate in the liver and kidneys of one subject with bilateral severely corroded head-neck junctions might suggest possible metal toxicity. The diagnosis of adverse tissue reactions to corrosion of modular junctions can be challenging. Postmortem retrieval studies add to our understanding of the nature and progression of lymphocyte-dominated adverse local and potentially systemic tissue reactions to corrosion of modular junctions

Background. Joint replacement surgery has been shown to be successful in post solid organ transplantation patients. However, complication rates, revision rates, and overall mortality can be higher in this population compared to patients who have not undergone solid organ transplantation. Many transplant patients have a decreased life expectancy. Therefore, literature suggests that joint replacement surgery be offered to qualifying patients early on when symptomatic. This study compares the outcomes of patients who have undergone solid organ transplantation as well as a joint replacement to patients that have only undergone joint replacement surgery. Methods. We retrospectively gathered 42 transplant (T) patients over a ten year period, 2003–2013, that underwent a liver (21) or kidney (21) transplant as well as primary total knee arthroplasty (TKA) (23) or total hip arthroplasty (THA) (19). We then gathered 42 non-transplant (NT) patients matched for procedure, age, body mass index (BMI), American Society of Anesthesiologists (ASA) score, and age adjusted Charlson co-morbidity index (ACCI) score who only underwent TKA or THA with no transplant. We used Chi-Square, T test, and multivariate analysis to compare the two groups with regard to number of complications (NOC), readmissions at 30 and 90 days post surgery, length of stay (LOS), number of intensive care unit (ICU) admissions, and total direct cost (TDC) per hospital stay. Results. We found no significant difference between the two groups with regard to LOS (P=0.267), readmissions at 30 days (P=0.843) or 90 days (P=0.265), ICU admissions (P=0.326), or TDC per hospital stay (P=0.343). The T group had significantly higher NOC compared to the NT group (P=0.022). The type of transplant was associated with a higher NOC with kidney transplant patients having 6.75 (95% CI 1.318–34.565) times higher odds of complications compared to liver transplant patients (P=0.022). The average time between transplant surgery and joint replacement surgery was 2.9 years. Conclusion. Solid organ transplant patients are considered to be at higher risk for opportunistic infections compared to the general population. Limited data is available regarding the time at which transplant patients are at the highest risk for infection, or if one type of transplant is more at risk for complications than another after THA or TKA. This study suggests that transplant patients undergoing joint replacement surgery at an average of 2.9 years post-transplant are at higher risk for complications than a matched cohort of patients undergoing joint replacement alone, with kidney transplant patients being more at risk to experience a complication than liver transplant patients. To our knowledge, this is the first study to acknowledge the higher risk associated specifically with kidney transplant patients

Aim. Chronic bone infections and infected fractures are often treated with excision of the dead bone and implantation of biomaterials which elute antibiotics. Gentamicin has been a preferred drug for local delivery, but this could induce renal dysfunction due to systemic toxicity. This is a particular concern in patients with pre-existing chronic renal disease treated with new antibiotic carriers which achieve very high peak levels of gentamicin in the first few days after surgery. Method. 163 patients (109 males; average age 51.6 years) with Cierny-Mader Type 3 or 4 chronic osteomyelitis had a single-stage operation with excision of the dead bone, filling of the osseous defect with a calcium sulphate-hydroxyapatite carrier, containing gentamicin and immediate soft tissue closure. 2. No patient was given systemic gentamicin or other renal toxic antibiotics. Mean carrier volume was 10.9mls (range 1–30mls) and mean gentamicin dosing was 190.75mg (maximum 525mg). Seven patients had pre-existing renal disease (4 diabetic nephropathy, 1 nephrotic syndrome, 1 renal transplant and 1 previous acute kidney injury). Serum creatinine levels were collected pre-operatively and during the first seven days post-operatively. Glomerular filtration rate (GFR) was calculated using the CKD-epi creatinine equation. Renal function was defined using the Chronic Kidney Disease (CKD) Staging system. Results. 155 cases had adequate data to allow calculation of pre- and post-operative GFR. Pre-operative CKD staging demonstrated 118 Class I (normal renal function), 30 Class II, 3 Class IIIa, 3 Class IIIb, and 1 Class V disease. Mean pre-operative GFR (99.7ml/min/1.73m. 2. , SD 21.0) was no different to post-operative GFR (103.2ml/min/1.73m. 2. , SD 21.3), p= 0.0861. Four cases had a >10% decline in GFR below normal, with only one case dropping a CKD stage, from I (normal) to II (mildly decreased). Only 1/7 cases with pre-existing renal disease had a GFR drop of >10% (from 11ml/min/1.73m. 2. to 8ml/min/1.73m. 2. ). 70/155 (45.2%) had a temporary GFR drop post-operatively, with the biggest drop occurring a mean 3.06 days following surgery (SD 2.1). No patient had clinical signs of new acute renal impairment post-operatively. Conclusions. Renal function is not significantly affected by local implantation of gentamicin up to 525mg. The presence of pre-existing renal disease is not a contraindication to local gentamicin therapy

Introduction. The treatment of chronic bone infection often involves excision of dead bone and implantation of biomaterials which elute antibiotics. Gentamicin is a preferred drug for local delivery, but its systemic use carries a well-established risk of nephrotoxicity. We aim to establish the risk of renal injury with local delivery in a ceramic carrier. Materials and Methods. 163 consecutive patients with Cierny-Mader Type 3 or 4 chronic osteomyelitis were treated with a single-stage operation which included filling of the osseous defect with a calcium sulphate-hydroxyapatite carrier containing gentamicin. The mean carrier volume used was 10.9mls, leading to a mean implanted gentamicin dose of 191.3mg (maximum 525mg). Serum creatinine levels were collected pre-operatively and during the first seven days post-operatively. Renal impairment was graded using the Chronic Kidney Disease (CKD) Staging system, and AKI was assessed using the RIFLE criteria. Results. 155 cases had adequate data to allow calculation of pre- and post-operative GFR. 7 patients had pre-existing renal disease. 70 patients (45.2%) had a temporary eGFR drop post-operatively, with the greatest decrease occurring a mean 3.06 days following surgery. Twenty cases had a >10% decline in eGFR, but 12 resolved within 7 days. 7 patients transiently fell into the “Risk” category according to RIFLE criteria, but no patient had a change consistent with “Injury”, “Failure” or “Loss” of renal function and none had clinical signs of new acute renal impairment post-operatively. Conclusions. The implantation of up to 525mg of gentamicin contained within Cerament G, as part of the surgical treatment of osteomyelitis, is safe and carries minimal risk of significant acute kidney injury. A small, transient increase in serum creatinine may be observed in the early post-operative period, and attention should be paid to limit patients exposure to other nephrotoxic agents. The majority of patients will return to their baseline renal function within 7 days following the operation. The presence of pre-existing renal disease is not a contraindication to local gentamicin therapy

Periprosthetic joint infection (PJI) is one of the most devastating complications of total joint arthroplasty (TJA). Only a few studies have investigated PJI's impact on the most worrisome of all endpoints, mortality. The purpose of this study was to perform a large-scale study to determine the rates of PJI associated in-hospital mortality, and compare it to other surgical procedures. The Nationwide Inpatient Sample was queried from 2002 to 2010 to assess the risk of mortality for patients undergoing revision for PJI or aseptic failures. Elixhauser comorbidity index and ICD-9 codes were used to obtain patients’ medical conditions and identify PJI. Multiple logistic-regression analyses were used to determine the associated variables with mortality. In-hospital mortality was compared to the followings: coronary-artery bypass graft, mastectomy, prostatectomy, appendectomy, kidney transplant, carotid surgery, cholecystectomy, and coronary interventional procedures. PJI was associated with an increased risk (odds ratio 2.04) of in-hospital mortality (0.77%) compared to aseptic revisions (0.38%). The in-hospital mortality of revision THAs done for PJI (1.38%, 95%CI, 1.12–1.64%) was comparable to or higher than interventional coronary procedure (1.22%, 95%CI, 1.20–1.24%), cholecystectomy (1.13%, 95%CI, 1.11–1.15%), kidney transplantation (0.70%, 95%CI, 0.61%–0.79%) and carotid surgery (0.89%, 95%CI, 0.86%–0.93%) (Figure 1). The following comorbidities were independent risk factors for in-hospital mortality after TJA: liver disease, metastatic disease, fluid and electrolyte disorders, coagulopathy, weight loss and malnutrition, congestive heart failure, pulmonary circulation disorder, renal failure, and peripheral vascular disease. PJI is associated with a two-fold increase in mortality and have mortality rates comparable to kidney transplantation and carotid surgery. Considering the fact that patients with PJI often require multiple surgical procedures, the rate of actual in-hospital mortality for patients with PJI may be considerably higher. Surgeons should be cognizant of the potentially fatal outcome of PJI and must emphasize the importance of infection control to reduce the risk of mortality

Introduction. Little is known about the relationship between head-neck corrosion and its effect on periprosthetic tissues and distant organs in the majority of patients hosting apparently well-functioning devices. We studied the degree and type of taper damage and the histopathologic response in periprosthetic tissue and distant organs. Methods. A total of 50 contemporary THRs (34 primary, 16 revision) retrieved postmortem from 40 patients after 0.4–26 years were studied. Forty-three femoral stems were CoCrMo and 7 were Ti6Al4V. In every case, a CoCrMo-alloy head articulated against a cementless polyethylene cup (19 XLPE and 31 UHMWPE). H&E and IHC sections of the joint pseudocapsules and liver were graded 1–4 for the intensity of various inflammatory cell infiltrates and tissue necrosis. The nature of the tissue response in the joint capsule, liver, spleen, kidneys and lymph nodes was assessed. Wear and corrosion products in the tissues were identified using SEM and EDS. Taper surfaces were graded for corrosion damage using modified Goldberg scoring and examined by SEM to determine the acting corrosion mode. Correlations between damage scores and the histologic variables were generated using the Spearman test. Results. No correlation was seen between taper damage scores and the macrophage response in the joint pseudocapsule. The distribution of corrosion scores for heads and femoral trunnions is shown in Figure 1. Moderate or severe corrosion of the head and/or trunnion was present in 9 hips (8 CoCr/CoCr and 1 CoCr/TiAlV). One patient with bilateral hips had local ALVAL-like lymphocyte-dominated tissue reactions (Figure 2) and mild focal lymphocytic infiltrates in the liver and kidneys (Figure 3). This was associated with severe intergranular corrosion of the CoCrMo trunnion and column damage on the head taper. Particle-laden macrophages in pseudocapsules were significantly correlated with liver macrophages (r=.382, p=0.012) and liver lymphocytes (r=.367, p=0.013). Pseudocapsule macrophage responses to metallic and/or polyethylene wear particles ranged widely from minimal to marked. Focal tissue necrosis was related to high concentrations of particulate wear debris. A minimal number of metallic particle-laden macrophages were also detected in the liver and spleen; and macrophage granulomas were present in para-aortic lymph nodes, especially in revision cases. DISCUSSION. The generation of metal ions and particulates at corroded CoCrMo heads and CoCrMo or Ti6Al4V trunnions was a significant contributor to the presence of perivascular lymphocytes within the joint pseudocapsule, with 1 patient showing a histologic pattern consistent with ALVAL. Patient factors and the rate of corrosion are among variables influencing whether an ALVAL-type reaction will develop and whether or not it will become symptomatic. Macrophages in the joint pseudocapsules were positively correlated with inflammatory cells in the liver. In this study, the intensity of inflammatory infiltrates in distant organs was mild. However, several cases of organ dysfunction have been reported in association with catastrophic wear of CoCrMo components. It continues to be essential to minimize the generation of metal ions and particulates and to improve strategies for identifying and managing patients exposed to high levels of degradation products. For any figures or tables, please contact the authors directly

Spinal metastases are seen in 10–30% of cancer patients. Twenty percent of these metastases occur in the lumbo-sacral spine. Lumbo-sacral spine has different mechanical properties and encloses the cauda equina. Few studies took interest in this spinal segment. The objective of this study is to evaluate prognostic factors of lumbo-sacral spinal metastasis treated in our center. We retrospectively reviewed 376 patients who were operated in our center from 2010 to 2018. Eighty-nine patients presented lumbo-sacral metastases and thus were included. Data collected included age, smoking, tumor histology, American spinal injury association (ASIA) score, modified Tokuhashi score, modified Bauer score, ambulation status and adjuvant treatment. The mean population age was 60.9 years old (35–85). The tumor histology was predominantly lung (19 patients, 21.3%), breast (13 patients, 14.6%), kidney (11 patients, 12.4%) and prostate (9 patients 10.1%). Twenty-two patients (24.7%) were unable to walk preoperatively. Seventy-nine patients (88.8%) underwent a posterior open approach with corpectomy in 65 patients (73%). Eighteen patients regained ambulation post-operatively (81.8%). The mean survival was 24.03 months (CI95% 17,38–30,67, Range 0–90) and the median of survival was 9 months (CI95% 4.38–13.62). Better preoperative ASIA score had a significant favorable effect (p=0.03) on survival. Patients who regained their ability to walk had better survival (25.1 months (CI95% 18.2–32) VS 0.5 months (CI95% 0–1.1). Postoperative radiotherapy had a benefic effect on survival (p=0.019): Survival Increased from 10.5 months (CI95% 2.4–18.7) to 27.6 months (CI95% 19.5–35.8). The modified Tokuhashi and the modified Bauer scores underestimated the survival of the patients with lumbosacral metastases. Lumbosacral spinal metastases has better survival than expected by Tokuhashi and Bauer score. Surgical procedure have an important impact on survival and the ability to walk

Introduction. About 2% of primary total joint replacement arthroplasty (TJA) procedures become infected. Periprosthetic joint infection (PJI) is currently one of the main reasons requiring costly TJA revisions, posing a burden on patients, physicians and insurance companies. 1. Currently used drug-eluting polymers such as bone cements offer limited drug release profiles, sometimes unable to completely clear out bacterial microorganisms within the joint space. For this study we determined the safety and efficacy of an antibiotic-eluting UHMWPE articular surface that delivered local antibiotics at optimal concentrations to treat PJI in a rabbit model. Materials and Methods. Skeletally mature adult male New Zealand White rabbits received either two non-antibiotic eluting UHMWPE (CONTROL, n=5) or vancomycin-eluting UHMWPE (TEST, n=5) (3 mm in diameter and 6 mm length) in the patellofemoral groove (Fig. 1). All rabbits received a beaded titanium rod in the tibial canal (4 mm diameter and 12 mm length). Both groups received two doses of 5 × 10. 7. cfu of bioluminescent S. aureus (Xen 29, PerkinElmer 119240) in 50 µL 0.9 % saline in the following sites: (1) distal tibial canal prior to insertion of the rod; (2) articular space after closure of the joint capsule (Fig. 1). None of the animals received any intravenous antibiotics for this study. Bioluminescence signal (photons/second) was measured when the rabbits expired, or at the study endpoint (day 21). The metal rods were stained with BacLight. ®. Bacterial Live-Dead Stain and imaged using two-photon microscopy to detect live bacteria. Hardware, polyethylene implants and joint tissues were sonicated to further quantify live bacteria via plate seeding. Results. All control rabbits expired within 7 days (Fig. 2a). One rabbit in the test group expired at day 7 and another at day 15. All control rabbits had positive bioluminescence (live bacteria), while none of the test rabbits did (Fig 2b). Kidney (creatinine and BUN) and liver functions (ALT and ALP) remained normal for all rabbits. All control rabbits showed positive bacterial culture after sonication, while all test rabbits were negative. Two-photon imaging showed 75±10 % viability for bacteria adhered to the metal rods in the control and no viability in the test group. Discussion. This rabbit model showed that vancomycin eluted from UHMWPE is sufficient to eradicate S. aureus in joint space and in between the bone-implant interface of tibial canal. One limitation of this study is the lack of intravenous antibiotic treatment, which is standard clinical practice. In addition, joint infections are often associated with already formed biofilms, which were not tested in this study. However, safety data (normal kidney and liver functions) and complete eradication of S. aureus is an encouraging finding. Conclusion. Vancomycin-eluting UHMWPE effectively eliminated bacteria in a rabbit model of acute peri-prosthetic joint infection. This material is promising as a replacement liner to treat joint infections in revision surgery. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Aim. The use of piperacillin/tazobactam with vancomycin as empirical antimicrobial therapy (EAT) for prosthetic joint infection (PJI) has been associated with an increased risk of acute kidney injury (AKI), leading to propose cefepim as an alternative since 2017 in our reference center. The present study compared microbiological efficacy and tolerance of these two EAT strategies. Method. All patients with PJI empirically treated by vancomycin-cefepim (n=90) were prospectively enrolled in an observational study, and compared with vancomycin-piperacillin/tazobactam-treated historical controls (n=117), regarding: i) the proportion efficacious empirical regimen (i.e., at least one of the two molecules active against the identified organism(s) based on in vitro susceptibility testing); and ii) the incidence of empirical therapy-related adverse events (AE), classified according to the Common terminology criteria for AE (CTCAE). Results. Among the 146 (67.3%) documented infections, the EAT was considered as efficacious in 99 (99.0%) and 66 (98.5%) in the piperacillin-tazobactam and cefepim-treated patients, respectively (p=0.109). The rate of adverse events, and in particular AKI, was significantly higher in the vancomycin-piperacillin/tazobactam (n=38 [32.5%] and 32 [27.6%]) compared to the vancomycin-cefepim (n=13 [14.4%] and 5 [5.7%]) group (p=0.003 and <0.001, respectively). Of note, sex, age, and the proportion of patients receiving other nephrotoxics were similar among piperacillin/tazobactam- and cefepim-treated patients. However, in comparison with patients receiving cefepim, a higher modified Charlson's comorbitidy index (4 [IQR, 3–5] versus 2 [IQR, 2–4], p<0.001) has to be acknowledged, mainly related to a higher prevalence of baseline chronic renal injury (n=62, 53.4% versus n=34, 38.6%; p=0.035). Conclusions. The empirical use of vancomycin-cefepim in PJI was as efficient as vancomycin-piperacillin/tazobactam, and was associated with a significantly lower incidence of AKI

Aim. Focused high energy extracorporeal shockwave therapy (fhESWT) is used to support fracture healing in non-union cases and has been shown to have antibacterial effects. We trialed fhESWT as an adjunct to conventional treatment in a clinically relevant rabbit model of fracture related infection. Method. A complete humeral osteotomy was performed in 31 rabbits and fixed with a 7-hole-LCP. A fracture-related infection (FRI) was established with Staphylococcus aureus. After two weeks, a revision surgery was performed with debridement, irrigation and implant retention. Rabbits then received: no further treatment (controls); shockwaves (at day 2 and 6 after revision, 4'000 Impulses each time with 23kV); systemic antibiotics (rifampin and nafcillin) over one week in weight adjusted dosages; or the combination of antibiotics and shockwaves. Treatments were applied over one week. Blood cultures were taken before and after shockwave sessions. After an additional week without treatment, rabbits were euthanized, and quantitative bacteriology was performed on implants and tissues to determine infection burden. Indicator organs (brain, heart, liver, lungs, kidneys and spleen) were cultured to assess possible bacteraemia due to fhESWT. Results. All rabbits were infected at revision surgery as determined by bacteriological culture of debrided materials. fhESWT in combination with antibiotic treatment lowered the bacterial burden at euthanasia hundredfold compared to antibiotic treatment alone in all samples (p=0.38). This effect was most prevalent for the implant sample (p=0.08). No significant effect was seen for fhESWT alone compared to untreated controls. No signs of bacteraemia occurred. Conclusions. The additon of systemic antibiotics had the biggest effect on reduction of bacteria. Although further lowering the bacterial burden in our model the effect of fhESWT as an adjunct was not big enough to be statistically secured in this in vivo rabbit model. In certain difficult-to-treat infections the addition of fhESWT might be beneficial. The method appears to be safe in this model of acute FRI as no signs of bacteremia occurred despite the high energy and impulse number. Further investigations are needed to identify the correct indication

An interesting case with excellent accompanying images, highlighting the significance of tourniquets in controlling exsanguination, whilst also raising the issue of amputation versus reconstruction in severely injured limbs. A 39 year old male motorcyclist was BIBA to the Midland Regional Hospital in Tullamore, following a head-on collision with a bus at high velocity. On arrival, he was assessed via ATLS guidelines; A- intubated, B- respiratory rate 32, C - heart rate 140bpm, blood-pressure 55/15 and D- GCS 7/15. Injuries included partial traumatic amputation of the right lower limb with clearly visible posterior femoral condyles, a heavily comminuted distal tibial fracture and almost complete avulsion of the skin and fat at the popliteal fossa. Obvious massive blood loss at the scene had been tempered by a passer-by who applied a beach towel as a makeshift tourniquet. CT Brain demonstrated extra-dural and subarachnoid haemorrhages with gross midline shift. Unfortunately, the neurosurgical team in Beaumont concluded that surgical intervention would be inappropriate. However, his kidneys had not sustained ATN and were made available for donation. Two vital surgical issues were featured in this case. Firstly, it highlighted the importance of tourniquets in controlling exsanguination in a trauma situation. 1. Secondly, it raised the critical issue of amputation versus reconstruction in severely injured limbs. 2,3. . Without prompt placement of a make-shift tourniquet by a passer-by, this patient would have almost certainly died at the scene of the accident. Two kidneys were successfully donated as a result. The importance of appropriate tourniquet use cannot be overstated. This case highlights its potential life or limb-saving capabilities in emergency trauma situations. It also raises the critical issue of amputation versus reconstruction in acute emergency situations

Aim. Silver is known for its excellent antimicrobial activity, including activity against multiresistant strains. The aim of the current study was to analyze the biocompatibility and potential influence on the fracture healing process a silver-coating technology for locking plates compared to silver-free locking plates in a rabbit model. Methods. The implants used in this study were 7-hole titanium locking plates, and plasma electrolytic oxidation (PEO) silver coated equivalents. A total of 24 rabbits were used in this study (12 coated, 12 non-coated). An osteotomy of the midshaft of the humerus was created with an oscillating saw and the humerus stabilized with the 7 hole locking plates with a total of 6 screws. X-rays were taken on day 0, week 2, 4, 6, 8, and 10 for continuous radiographical evaluation of the fracture healing. All animals were euthanized after 10 weeks and further assessment was performed using X-rays, micro-CT, non-destructive four-point bending biomechanical testing and histology. Furthermore, silver concentration was measured in the kidney, liver, spleen and brain. Results. X-rays showed normal undisturbed healing of the osteotomy in all animals without any differences between the two groups over the entire X-ray analysis over 10 weeks (Figure 1). Callus formation was observed up to week 4 to 5 followed by callus remodeling after 6 weeks indicating physiological fracture healing pattern in both the silver and in the silver free group. Micro CT analysis revealed overall tissue (callus and cortical bone) volume as well as tissue density to be comparable between the two groups. Mechanical testing showed comparable stiffness with an average stiffness relative to contralateral bones of 75.7 ± 16.1% in the silver free control group compared to 69.7 ± 18.5% (p-value: 0.46). Histology showed no remarkable difference in the analysis of the healed osteotomy gap or in the surrounding soft tissue area. Silver content was found to be close to baseline values without differences between the two groups. Conclusions. This study shows that the presented antimicrobial silver surface modification for locking plates has a good biocompatibility without any negative influence on the fracture healing processes compared to the silver free control group. This allows for further clinical investigation of this silver technology for locking plates in fracture patients with an elevated infection risk, e.g. in patients with open fractures. For any figures or tables, please contact the authors directly