Aims. Echocardiography is commonly used in hip fracture patients to evaluate perioperative cardiac risk. However, echocardiography that delays surgical repair may be harmful. The objective of this study was to compare surgical wait times, mortality, length of stay (LOS), and healthcare costs for similar hip fracture patients evaluated with and without preoperative echocardiograms. Methods. A population-based, matched cohort study of all hip fracture patients (aged over 45 years) in Ontario, Canada between 2009 and 2014 was conducted. The primary exposure was preoperative echocardiography (occurring between hospital admission and surgery). Mortality rates, surgical wait times, postoperative LOS, and medical costs (expressed as 2013$ CAN) up to one year postoperatively were assessed after propensity-score matching. Results. A total of 2,354 of 42,230 (5.6%) eligible hip fracture patients received a preoperative echocardiogram during the study period. Echocardiography ordering practices varied among hospitals, ranging from 0% to 23.0% of hip fracture patients at different hospital sites. After successfully matching 2,298 (97.6%) patients, echocardiography was associated with significantly increased risks of mortality at 90 days (20.1% vs 16.8%; p = 0.004) and one year (32.9% vs 27.8%; p < 0.001), but not at 30 days (11.4% vs 9.8%; p = 0.084). Patients with echocardiography also had a mean increased delay from presentation to surgery (68.80 hours (SD 44.23) vs 39.69 hours (SD 27.09); p < 0.001), total LOS (19.49 days (SD 25.39) vs 15.94 days (SD 22.48); p < 0.001), and total healthcare costs at one year ($51,714.69 (SD 54,675.28) vs $41,861.47 (SD 50,854.12); p < 0.001). Conclusion. Preoperative echocardiography for hip fracture patients is associated with increased postoperative mortality at 90 days and one year but not at 30 days. Preoperative echocardiography is also associated with increased surgical delay, postoperative LOS, and total healthcare costs at one year. Echocardiography should be considered an urgent test when ordered to prevent additional surgical delay. Cite this article: Bone Joint J 2021;103-B(2):271–278

Aims. Elevated blood cobalt levels secondary to metal-on-metal (MoM) hip arthroplasties are a suggested risk factor for developing cardiovascular complications including cardiomyopathy. Clinical studies assessing patients with MoM hips using left ventricular ejection fraction (LVEF) have found conflicting evidence of cobalt-induced cardiomyopathy. Global longitudinal strain (GLS) is an echocardiography measurement known to be more sensitive than LVEF when diagnosing early cardiomyopathies. The extent of cardiovascular injury, as measured by GLS, in patients with elevated blood cobalt levels has not previously been examined. Methods. A total of 16 patients with documented blood cobalt ion levels above 13 µg/l (13 ppb, 221 nmol/l) were identified from a regional arthroplasty database. They were matched with eight patients awaiting hip arthroplasty. All patients underwent echocardiography, including GLS, investigating potential signs of cardiomyopathy. Results. Patients with MoM hip arthroplasties had a mean blood cobalt level of 29 µg/l (495 nmol/l) compared to 0.01 µg/l (0.2 nmol/l) in the control group. GLS readings were available for seven of the MoM cohort, and were significantly lower when compared with controls (-15.5% vs -18% (MoM vs control); p = 0.025)). Pearson correlation demonstrated that GLS significantly correlated with blood cobalt level (r = 0.8521; p < 0.001). However, there were no differences or correlations for other echocardiography measurements, including LVEF (64.3% vs 63.7% (MoM vs control); p = 0.845). Conclusion. This study supports the hypothesis that patients with elevated blood cobalt levels above 13 µg/l in the presence of a MoM hip implant may have impaired cardiac function compared to a control group of patients awaiting hip arthroplasty. It is the first study to use the more sensitive parameter of GLS to assess for any cardiac contractile dysfunction in patients with a MoM hip implant and a normal LVEF. Larger studies should be performed to determine the potential of GLS as a predictor of cardiac complications in patients with MoM arthroplasties. Cite this article: Bone Joint J 2024;106-B(3 Supple A):51–58

Echocardiography is commonly used in hip fracture patients to evaluate perioperative cardiac risk and identify cardiac abnormalities. However, echocardiography that delays surgical repair may be harmful. The objective of this study was to compare mortality, surgical wait times, length of stay (LOS), and health care costs for similar hip fracture patients managed with and without preoperative echocardiography. A population based, retrospective cohort study of all hip fracture patients (>age 45) in Ontario, Canada was conducted. The primary exposure was pre-operative echocardiography (between hospital admission and surgery). Patients receiving preoperative echocardiography were matched to those without using a propensity score incorporating patient demographic information, comorbidity status, and provider information. Mortality rates, surgical wait times, post-operative length of stay (LOS), and medical costs (expressed as 2013$ CAN) up to one year post-operatively were assessed after matching. There were 2354 (∼5.6%) of 42,230 eligible hip fracture patients that received preoperative echocardiograghy during the study period. After successfully matching 2298 (∼97.6%) patients, echocardiography was associated with significant increases in mortality at 90 days (20.1% vs. 16.8%, p=0.004) and one year (32.9% vs. 27.8%, p < 0 .001), but not 30-days (11.4% vs. 9.8%, p=0.084). Patients with echocardiography also had an increased (mean ± SD) delay (in hours) from presentation to surgery (68.80 ± 44.23 hours vs. 39.69 ± 27.09 hours, p < 0 .001) and only 38.1% of patients had surgery within 48 hours. Total LOS (in days) (mean 19.49 ± 25.39 days vs. 15.94 ± 22.48 days, p < 0 .001) and total healthcare costs at one year (mean: $51,714.69 ± 54,675.28 vs. $41,861.47 ± 50,854.12, p < 0 .001) were also increased. There was wide variability in echocardiography ordering practice in Ontario, with a range of 0% to 22.97% of hip fracture patients undergoing preoperative echocardiography at different hospital sites. Preoperative echocardiography for hip fracture patients is associated with increased postoperative mortality. It is also associated with increased surgical delay, post-operative LOS, and total health care costs at one year. Echocardiography should be considered an urgent test when ordered to prevent additional surgical delay, and further research is necessary to clarify indications for this common preoperative investigation

Echocardiography is commonly used in hip fracture patients to evaluate perioperative cardiac risk and identify cardiac abnormalities. However, echocardiography that delays surgical repair may be harmful. The objective of this study was to compare mortality, surgical wait times, length of stay (LOS), and health care costs for similar hip fracture patients managed with and without preoperative echocardiograms. A population based, retrospective cohort study of all hip fracture patients (>age 45) in Ontario, Canada was conducted. The primary exposure was pre-operative echocardiography (between hospital admission and surgery). Patients receiving preoperative echocardiograms were matched to those without using a propensity score incorporating patient demographic information, comorbidity status, and provider information. Mortality rates, surgical wait times, post-operative length of stay (LOS), and medical costs (expressed as 2013$ CAN) up to 1-year post-operatively were assessed after matching. There were 2354 (∼5.6%) of 42,230 eligible hip fracture patients that received a preoperative echocardiogram during the study period. After successfully matching 2298 (∼97.6%) patients, echocardiography was associated with significant increases in mortality at 90 days (20.1% vs. 16.8%, p=0.004) and 1 year (32.9% vs. 27.8%, p < 0 .001), but not 30-days (11.4% vs. 9.8%, p=0.084). Patients with echocardiography also had an increased (mean ± SD) delay (in hours) from presentation to surgery (68.80 ± 44.23 hours vs. 39.69 ± 27.09 hours, p < 0 .001) and only 38.1% of patients had surgery within 48 hours. Total LOS (in days) (mean 19.49 ± 25.39 days vs. 15.94 ± 22.48 days, p < 0 .001) and total healthcare costs at 1 year (mean: $51,714.69 ± 54,675.28 vs. $41,861.47 ± 50,854.12, p < 0 .001) were also increased. There was wide variability in echocardiography ordering practice in Ontario, with a range of 0% to 22.97% of hip fracture patients undergoing preoperative echocardiography at different hospital sites. Preoperative echocardiography for hip fracture patients is associated with increased postoperative mortality. It is also associated with increased surgical delay, post-operative LOS, and total health care costs at 1 year. Echocardiography should be considered an urgent test when ordered to prevent additional surgical delay, and further research is necessary to clarify indications for this common preoperative investigation

We performed transoesophageal echocardiography in 111 operations (110 patients) which included medullary reaming for fresh fractures of the femur and tibia, pathological lesions of the femur, and hemiarthroplasty of the hip. Embolic events of varying intensity were seen in 97 procedures and measured pulmonary responses correlated with the severity of embolic phenomena. Twenty-four out of the 25 severe embolic responses occurred while reaming pathological lesions or during cemented hemiarthroplasty of the hip and, overall, pathological lesions produced the most severe responses. Paradoxical embolisation occurred in four patients, all with pathological lesions of the femur (21%); two died. In 12 patients large coagulative masses became trapped in the heart. Extensive pulmonary thromboembolism with reamed bone and immature clot was found at post-mortem in two patients; there was severe systemic embolisation of fat and marrow in one who had a patent foramen ovale and widespread mild systemic fat embolisation in the other without associated foraminal defect. Sequential analysis of blood from the right atrium in five patients showed considerable activation of clotting cascades during reaming

We performed transoesophageal echocardiography on 20 patients with femoral neck fractures randomly treated with an uncemented Austin-Moore or cemented Hastings hemiarthroplasty. Cemented arthroplasty caused greater and more prolonged embolic cascades than did uncemented arthroplasty. Some emboli were more than 3 cm in length. In some patients the cascades were associated with pulmonary hypertension, diminished oxygen tension and saturation, and the presence of fat and marrow in aspirates from the right atrium

We performed transoesophageal echocardiography on 24 patients during reamed intramedullary nailing of 17 tibial and seven femoral fractures. In 14 patients there was only minimal evidence of emboli passing through the heart, but in six copious showers of small emboli (< 10 mm maximum dimension) were observed. In four other patients, there were also multiple large emboli (> 10 mm maximum dimension). Three of these patients developed fat embolism syndrome postoperatively and one died. Earlier nailing was associated with smaller quantities of emboli

Elevated blood cobalt secondary to metal-on-metal (MoM) hip arthroplasties has been shown to be a risk factor for developing cardiovascular complications including cardiomyopathy. Published case reports document cardiomyopathy in patients with blood cobalt levels as low as 13µg/l (13ppb, 221nmol/l). Clinical studies have found conflicting evidence of cobalt-induced cardiomyopathy in patients with MoM hips. Global longitudinal strain (GLS) is an echocardiography measurement known to be more sensitive than ejection fraction at diagnosing early cardiomyopathies. The extent of cardiovascular injury, as measured by GLS, in patients with elevated blood cobalt levels has not previously been examined. Sixteen patients with documented blood cobalt ion levels above 13µg/l were identified from a regional arthroplasty database. They were matched with eight patients awaiting hip arthroplasty with no history of cobalt implants. All patients underwent electrocardiogram and echocardiogram assessment for signs of cardiomyopathy including GLS. Patients with MoM hip arthroplasties had a mean blood cobalt level of 29µg/l (495nmol/l) compared to 0.01µg/l (0.2nmol/l) in the control group. There was no difference or correlation in ejection fraction (EF), left ventricular (LV) end systolic dimension, LV end diastolic dimension, fractional shortening, ventricular wall thickness or E/e’ ratio. However, GLS was significantly reduced in patients with MoM hip arthroplasties compared to those without (−15.2% v −18%, (MoM v control) p= 0.0125). Pearson correlation demonstrated that GLS is significantly correlated with blood cobalt level (r= 0.8742, p=0.0009). For the first time, this study has demonstrated reduced cardiac function in the presence of normal EF as assessed by GLS in patients with elevated cobalt above 13µg/l. As GLS is a more sensitive measure of systolic function than EF, routine echocardiogram assessment including GLS should be performed in all patients with MoM hip arthroplasties and elevated blood cobalt above 13µg/l. Further work is recommended to assess if these cardiac changes are present in patients with elevated blood cobalt levels below 13µg/l

An audit of fractured neck of femur patients indicated that the delay in acquiring an echocardiogram was delaying surgery (time to echo 5.4 days ± 3.4SD (n=72), time to surgery 7.5 days ± 5.5SD (n=72)). This instigated a change in policy with the introduction of routine ‘targeted’ echocardiography performed by a cardiac technician at the patient’s bedside. A re-audit has demonstrated an improvement in service (time to echo 1.0 days ± 0.7SD (n=96), time to surgery 2.9 days ± 1.9SD (n=118)). A targeted echocardiogram consists of an evaluation of left ventricular function expressed as normal, mild, moderate and severe (left ventricular ejection fraction > 50%, 40–50%, 30–40% and < 30%), the aortic valve (normal, non severe aortic stenosis, severe aortic stenosis, aortic regurgitation and aortic gradient). A targeted echo gives less information than a departmental echo where more parameters are measured, however the information provided is enough to guide the anaesthetists choice of anaesthesia and intraoperative anaesthetic management. Senior Echo technicians perform the investigation at the patients bedside on the trauma ward in the mornings of the working week using a portable machine. Each echocardiogram takes 2 to 5 minutes to perform. If obvious significant other pathology is seen, the patient is referred for a full departmental echocardiogram. A total of 28.4 patient bed days per month were saved following this change in practice, assuming days waiting for echo preoperatively equate to extra days spent in hospital. The total cost saving per month was £4435, based on the cost of routine targeted echocardiography (£10), departmental echocardiography (£60) and bed cost (£155 per night). Expedient surgery within this group of patients should not be compromised by delays in obtaining timely echocardiography. The cost of routine ‘targeted’ echocardiography is low and this change in practice can be justified in both clinical and economic terms

Boys affected by Duchenne Muscular Dystrophy (DMD) often develop significant scoliosis in the second decade of life and require scoliosis surgery. Our aim was to establish whether cardiac MRI (CMR) improves the preoperative risk assessment in DMD patients and evaluate the current risk of surgery. Case records were retrospectively reviewed for 62 consecutive DMD boys who underwent pre-surgical evaluation at a single tertiary neuromuscular centre between 2008–2013. 62 DMD patients aged 7–18 years underwent pre-operative assessment for a total of 70 procedures (45 spinal, 19 foot, 6 gastrostomy). Echocardiography data were available for 68 procedures. Echo revealed a median left ventricular (LV) shortening fraction (SF) of 29% (range: 7–44). 34% of boys (23/68) had abnormal SF <25%, 48% (31/65) showed dyskinesia and 22% (14/64) had LV dilatation. CMR was routinely performed on 35 patients. Of those who underwent CMR, median left ventricular ejection fraction (LVEF) was 52% (range: 27–67%), 71% of boys (25/35) had dyskinesia. Echocardiography shortening fraction (SF) correlated significantly with CMR LVEF (r. s. = 0.67; p<0.001). Increasing severity of dyskinesia on CMR correlated with reduced CMR LVEF (r. s. = −0.64; p<0.001) and reduced echo SF (r. s. = −0.47; p = 0.004). Although functional echocardiography and CMR data tended to correlate in 35 DMD boys who underwent both imaging modalities nine (26%) had discrepant results. Seven (20%) had evidence of dysfunction on CMR (LVEF < 55%) not detected on echocardiography (SF ≥ 27%); in two cases echocardiogram measured worse function than CMR. Based on multi-disciplinary risk assessment, surgery was considered too high risk in 23 out of 67 (34%) cases. In 21 cases (91%) this was due to underlying cardiomyopathy. The highest risk among older boys assessed for spinal surgery; 21 out of 43 (49%). Of 19 boys undergoing spinal surgery, six (32%) experienced complications: two wound infections; three patients required readmission to intensive care; one patient died in the post-operative period with acute heart failure

Using an established canine model of fat embolization, the effect of temporary mechanical blockade of embolic load during medullary canal pressurization was studied. Haemodynamic measurements, echocardiography and postmortem histomorphometry were used as outcome measures. There was statistically significant difference between the filter and the control groups, when the pulmonary vascular resistance, the percentage area of lungs occupied by fat and the percentage of pulmonary vasculature occupied by fat were compared. We have shown that mechanical blockade by a filter does stop the adverse effect on the lungs during canal pressurization. Acute intramedullary stabilization of femoral fractures in multiply injured patients still remains controversial. Intravasation of medullary fat has been suspected to trigger ARDS. This study investigates the effect of a filter placed into the ipsilateral common iliac vein during medullary canal pressurization. Using an established canine model, twelve mongrel dogs were randomized into two groups. A special filter was inserted percutaneously into the left common iliac vein in half the dogs where as the other half served as controls. In all dogs, the left femora and tibiae were pressurized by injection of bone cement and insertion of intramedullary rods. Hemodynamic measurements and echocardiography images were recorded continuously. After sacrifice, the lungs were harvested for analysis. The mean pulmonary artery pressure at three minutes of pressurization was 12 mm of Hg in the filter group and 28mm of Hg in the control group. The pulmonary vascular resistance in the control group was increased from the 3. rd. minute of pressurization throughout the experiment. This was statistically significant when compared with the baseline. There was no such change seen in the filter group. Transesophageal echocardiography showed less embolic shower in the filter group and histomorphometry demonstrated statistically signifant difference, when the percentage area of lungs and the percentage of pulmonary vasculature occupied by fat in the filter group as compared to the control group. This canine study has demonstrated that mechanical blockade by a venous filters can significantly reduce the embolic load on the lungs during canal pressurization

Aim: To evaluate the morbidity and mortality in the perioperative period of patients with aortic stenosis following fractures of the proximal femur. Patients and Methods: A retrospective review was undertaken of medical notes of all patients (n=20) admitted to our trauma unit over an 18 month period with fractures of the proximal femur and concomitant aortic stenosis confirmed by transthoracic echocardiography. Assessment was made of perioperative factors thought to be important in influencing outcomes in such patients as highlighted in the 2001 Report of the National Confidential Enquiry into Patient Outcome and Death (NCEPOD) “Changing the way we operate”. These included previous history of angina or ischaemic heart disease, preoperative optimisation by an anaesthetist or physician, maximum pressure gradient across the aortic valve and ventricular ejection fraction on transthoracic echocardiography, seniority of anaesthetist and surgeon performing the procedure, intraoperative invasive monitoring, postoperative high dependency care and complications and outcomes. Results: Prior to surgery three patients (15%) were seen by a physician and nine patients (45%) by an anaesthetist for medical optimisation. The mean maximum pressure gradient across the aortic valve on transthoracic echocardiography was 38.6 mmHg (range: 12 to 111 mmHg), and five patients (25%) were confirmed as having severe aortic stenosis. Anaesthesia was performed by consultant anaesthetists in 85% of cases with the remaining 15% carried out by trainees. No patients had intraoperative central venous pressure (CVP) monitoring, and only three of the 20 (15%) patients had intra-arterial blood pressure (IABP) monitoring. Only two patients spent one day in the High Dependency Unit postoperatively. The remainder of the patients were discharged back to the general ward where the mean length of stay was 28 days (range: 0 to 135). Postoperatively two patients (10%) developed arrhythmias, three (15%) experienced an episode of acute left ventricular failure and four (20%) developed hypotension. There were two deaths (10%). Conclusion: It is evident that patients with proximal femoral fracture and concomitant aortic stenosis are still not benefiting from the recommendations of the NCEPOD report in the perioperative period. The authors suggest the introduction of a dedicated multidisciplinary team for the management of patients with proximal femoral fractures and concomitant aortic stenosis

Introduction and Aims: Acute intramedullary stabilisation of femoral shaft fractures in multiply injured patients remains controversial. Intravasation of medullary fat during nailing has been suspected to trigger ARDS. This study investigates the effect of a filter placed into the ipsilateral common iliac vein during medullary canal pressurisation in a canine experiment. Method: Using an established model, 12 mongrel dogs were randomised into two groups. Under general anesthesia, cannulations were performed to measure left and right-sided pressures. Transoesophageal echocardiography was performed in all dogs. A special ‘TRAP ‘filter was inserted percutaneously into the left common iliac vein in six dogs, whereas the other six served as controls. In all dogs, the left femora and tibiae were then pressurised by injection of bone cement and insertion of intramedullary rods. Hemodynamic measurements and echocardiography images were recorded continuously. After one hour, the animals were sacrificed and the lungs were harvested for histomorphommetric analysis. Results: The mean pulmonary artery pressure at three minutes of pressurisation was 12mm of Hg in the filter group and 28mm of Hg in the control group. There was increase in the peak systolic pulmonary artery pressure and the right ventricular pressure after canal pressurisation in the control group, whereas no such changes were observed in the filter groups. The pulmonary vascular resistance as denoted by the difference between the mean pulmonary artery pressure and the end diastolic left ventricular pressure increased significantly (p< 0.05) at three, five, 10,15 and 30 minutes after pressurisation in the control group when compared to the baseline value. In the filter group, the pulmonary vascular resistance increased only slightly after pressurisation. Transesophageal echocardiography images were analysed by a blinded echocardiologist. There was evidence of moderate to severe embolisation in the control group with detection of large echogenic particles. In comparison, there was mild grade of embolisation in the filter group. Histological analysis showed statistically significant difference between the two groups, when comparison of the percentage of area of lung tissue occupied by fat, the percentage of pulmonary vasculature occupied by fat and the maximum size of the embolus were made (p< 0.05). Conclusion: This study has conclusively demonstrated that mechanical blockade by venous filters prior to medullary canal pressurisation, significantly reduces the embolic load and its effect on the lungs. A retrievable filter with a system to remove the accumulated marrow content is being developed for use in high-risk patients

Systemic emboli released during total knee replacement have been implicated as a cause of peri-operative morbidity and neurological dysfunction. We undertook a prospective, double-blind, randomised study to compare the cardiac embolic load sustained during computer-assisted and conventional, intramedullary-aligned, total knee replacement, as measured by transoesophageal echocardiography. There were 26 consecutive procedures performed by a single surgeon at a single hospital. The embolic load was scored using the modified Mayo grading system for echogenic emboli. Fourteen patients undergoing computer-assisted total knee replacement had a mean embolic score of 4.89 (3 to 7) and 12 undergoing conventional total knee replacement had a mean embolic score of 6.15 (4 to 8) on release of the tourniquet. Comparison of the groups using a two-tailed t-test confirmed a highly significant difference (p = 0.004). This study demonstrates that computer-assisted knee replacement results in the release of significantly fewer systemic emboli than the conventional procedure using intramedullary alignment

Introduction:. Although the risk of pulmonary embolism (PE) or other embolic events associated with total joint arthroplasty have been recorded for some time, to date no direct means of these events in human arthroplasty have reported. This prospective study was designed to clarify the pathophysiologic mechanism of PE after total knee arthroplasty (TKA). Methods:. Nine patients fulfilling the following selection criteria were included in this prospective study: diagnosis of osteoarthosis, age 60 to 75 years, cemented primary TKA. All patients had a baseline pulmonary perfusion scan 2 days prior to the surgery. TKA was performed in the standard manner under general anesthesia. Monitoring of the heart chambers during the course of the TKA was performed using a 5 MHz ultrasonic transducer placed into the esophagus. The 4-chamber view plane of the heart was then imaged using a 2-dimensional echocardiography. A tip of the catheter inserted from the contralateral femoral vein was also placed in the inferior vena cava to harvest the venous blood flowed from the suffered lower extremity before and after tourniquet release. All patients had pulmonary perfusion scans 3 hours after TKA and on the 21st postoperative day. The ventilation-perfusion scan was compared with the baseline perfusion scan. Results:. No symptomatic PE were identified. Using transesophageal echocardiographic monitoring, the heaviest flow of embolic particles in the right heart was observed 2 seconds after tourniquet release and lasted approximately 30 seconds. By squeezing the calf muscle, the heavy flow of embolic particles was again observed. The venous blood harvested through the catheter after tourniquet release had fat droplets and white coagula. All of patients had pulmonary perfusion defects 3 hours after TKA, but no pulmonary perfusion defects on the 21st postoperative day. Discussion and Conclusions:. Substantial amounts of embolic materials were seen in the right heart using transesophageal echocardiography in patients operated in the standard manner. It was demonstrated that these embolic materials consisted of fat droplets and white coagula. We also demonstrated that many embolic materials for PE and/or DVT originated in the calf. All of patients had pulmonary perfusion defects just after TKA. It was concluded that all of the patients who underwent TKA had asymptomatic PE just after the surgery. Therefore, all of the patients have a possibility of symptomatic PE just after TKA

Introduction: Early stabilization of the skeleton in multiply injured patients has shown to reduce mortality and chest morbidity. Reamed intramedullary nailing is the current method of choice for stablizing femoral and tibial shaft fracture. However several investigators have highlighted the adverse effect of early reamed nailing in polytrauma patients. Intravasation of medullary fat during canal pressurizaton has been suspected to produce a ‘second hit’ and trigger pneumonia and ARDS. The objective of this study is to investigate the effect of a filter placed into the ipsilateral common iliac vein during medullary canal pressurization. Methods: Using an established model of fat embolization, twelve mongrel dogs were randomized into two groups. Under general anaesthesia, cannulations of carotids and jugular veins and transesophageal echo-cardiography were performed in all animals. Under fluoroscopy control, a special filter was inserted percutaneously into the left common iliac vein in half the animals, where as the other half served as controls. In all dogs, the left knee was exposed; the femor and tiiba were sequentially reamed and then pressurized by injection of bone cement and insertion of intramedullary rods. Hemodynamic measurements and trans-esophageal echocardiography images were recorded continuously during the surgical procedure. After 45 minutes from pressurization, the dogs were sacrificed and the lungs and kidneys were harvested and fixed for histological analysis. Results: There was significant difference noticed in the right-sided pressures and oxygen tension between the filter and the control groups. The mean pulmonary artery pressure at 3 minutes of pressurization was 12mm of Hg in the filter group and 28mm of Hg in the control group. Transesophageal echocardiography showed less embolic shower in the filter group and also lesser dilatation of right ventricles. Histomorphometry with special staining demonstrated much less proportion of lungs to be occupied by fat in the filter group as compared to the control group. Discussion and Conclusion: This canine study has demonstrated that mechanical blockade by a venous filter can significantly reduce the emobilic load on the lungs in an established model of fat embolization. A suitable filter with suction system is being designed for possible use in high-risk patients

Aim. The incidence of hematogenous periprosthetic joint infections (hPJI) is unknown and the cases probably largely underreported. Unrecognized and untreated primary infectious foci may cause continuous bacteremia, further spread of microorganisms and thus treatment failure or relapse of infection. This study aimed at improving knowledge about primary foci and microbiological characteristics of this entity to establish preventive measures and improve diagnostic and therapeutic strategies to counteract hPJI. Method. We retrospectively analysed all consecutive patients with hPJI, who were treated at our institution from January 2010 until December 2016. Diagnosis of PJI was established if 1 of the following criteria applied:(i) macroscopic purulence, (ii) presence of sinus tract, (iii) positive cytology of joint aspirate (>2000 leukocytes/μl or >70% granulocytes), (iv) significant microbial growth in synovial fluid, periprosthetic tissue or sonication culture of retrieved prosthesis components, (v) positive histopathology. PJI was classified as hematogenous if the following criteria were fulfilled additionally: (1) onset of symptoms more than 1 month after arthroplasty AND (2) i) isolation of the same organism in blood cultures OR ii) evidence of a distant infectious focus consistent with the pathogen. Results. A total of 70 episodes of hPJI were included. Median age was 74 years (32–89 years), 36 were women and 29 men. Sites of PJI included 39 knees, 29 hips, one shoulder and one elbow joint. The pathogen was identified in 99% (n=69), the majority of episodes was monomicrobial (n=64, 91%). Blood cultures were collected in 39 cases (56%) and identified the pathogen in 67% (n=26). Isolated pathogens were Staphylococcus aureus (n=29), Streptococcus spp. (n=20) and Enterococcus faecalis (n=12), coagulase-negative staphylococci (n=6) and gram-negative bacilli (n=5). In 55% the primary focus was identified and included an intravascular (endocarditis, endoplastitis, thrombophlebitis; n=15), urogenitary (n=8), dental (n=6), gastrointestinal (n=5) and osteoarticular (n=2) and skin and soft tissue origin (n=1). The primary focus could not be identified in 29 cases (41%), primarily due to underuse of diagnostic workup. Conclusions. Causative agents were identified in the vast majority of hPJI with a predominance (75%) of high virulent microorganisms such as staphylococci, streptococci and gram-negative bacilli. Our results highlight the importance of a meticulous diagnostic workup including collection of blood cultures and performance of echocardiography in hematogenous PJI in order to cure the infection and prevent relapse. Awareness must be raised with regard to every prosthesis being endangered by hematogenous seeding from a distant infectious focus during the entire indwelling time

Circulating cobalt and chromium from metal-on-metal implants cause rare but fatal autopsy-diagnosed cardiotoxicity. Concern exists that milder cardiotoxicity may be common and under-recognized. Unacceptably high failure rates of metal-on-metal hip implants have prompted regulatory authorities to issue worldwide safety alerts. Despite this, approximately 1 million patients continue to live with metal-on-metal implants, putting them at risk of systemic toxicity. Although blood cobalt and chromium levels are easily measured and track local toxicity, no non-invasive tests for organ deposition exist. We recently demonstrated the utilisation of a T2* protocol (cardiovascular MRI) to detect cobalt and chromium deposition within the liver of a patient with elevated blood cobalt levels (confirmed by liver biopsy tissue analysis and X-ray fluorescence spectroscopy). We sought to detect and constrain the correlation between blood metal ions and a comprehensive panel of established markers of early cardiotoxicity. In addition we applied T2* protocols with the aim of detecting cardiac metal deposition. 90 patients were recruited through RNOH clinics into this prospective single centre blinded study. Patients were divided into 3 age and gender-matched groups according to type of implant and blood metal ion levels as follows: [Group A] Non-metal bearing hip implants; [Group B] Metal-on-metal implants, low blood metal ion levels (<7ppb); and [Group C] Metal-on-metal implants, high blood levels (>7ppb). All underwent detailed cardiovascular phenotyping using cardiac MRI (with T2*, T1 and ECV mapping, in addition to LV size and ejection fraction), advanced echocardiography (LV size and ejection fraction), and cardiac blood biomarker (Troponin and BNP) sampling in the same sitting at the Heart Hospital London. Primary outcomes were pre-specified. See study flow diagram – figure 1. (The study was registered with . clinicaltrials.gov. : NCT02331264). Blood cobalt levels were significantly different between groups (0.17ppb (range 0·10–0·47, SD 0·08) vs. 2·47 (0·72–6·9, SD 1·81) vs. 30·0 (7·54–118.0, SD 29·1) respectively for groups A, B and C). No significant between-group differences were found for LV size, ejection fraction (CMR or echocardiography), LA size, T1, T2*, ECV, BNP or troponin, with all results within normal ranges. There was no relationship between blood cobalt levels and either left ventricular ejection fraction or T2* (r=-0·022 and r=-0·108 respectively). Although small, the study was sufficiently powered to detect, as a minimum, a difference in ejection fraction of 4.8% (Cohen's d effect size 0·8). Using best available technologies, exposure of patients with metal-on-metal hip implants to high (but not extreme) blood cobalt and chromium levels has no detectable effect on the heart. We believe these findings will offer reassurance to one million patients worldwide living with a metal-on-metal hip implant and will support clinicians caring for such patients. For any figures or tables, please contact the authors directly by clicking on ‘Info & Metrics’ above to access author contact details

Elevated levels of circulating cobalt ions have been linked with a wide range of systemic complications including neurological, endocrine, and cardiovascular symptoms. Case reports of patients with elevated blood cobalt ions have described significant cardiovascular complications including cardiomyopathy. However, correlation between the actual level of circulating cobalt and extent of cardiovascular injury has not previously been performed. This review examines evidence from the literature for a link between elevated blood cobalt levels secondary to metal-on-metal (MoM) hip arthroplasties and cardiomyopathy. Correlation between low, moderate, and high blood cobalt with cardiovascular complications has been considered. Elevated blood cobalt at levels over 250 µg/l have been shown to be a risk factor for developing systemic complications and published case reports document cardiomyopathy, cardiac transplantation, and death in patients with severely elevated blood cobalt ions. However, it is not clear that there is a hard cut-off value and cardiac dysfunction may occur at lower levels. Clinical and laboratory research has found conflicting evidence of cobalt-induced cardiomyopathy in patients with MoM hips. Further work needs to be done to clarify the link between severely elevated blood cobalt ions and cardiomyopathy.

Cite this article: Bone Joint Res 2021;10(6):340–347.