Fifty-five adults who had sustained a tibial fracture, or a femoral fracture, or both, were subjected to a double-blind randomised study to determine the efficacy of methylprednisolone in treating the fat embolism syndrome. This drug maintained arterial oxygen levels, stabilised or reduced the serum level of free fatty acids, and decreased the risk of the fat embolism syndrome in a statistically significant proportion of patients. Gurd's criteria for the diagnosis of the fat embolism syndrome were found inadequate. Other more sensitive criteria for early diagnosis and effective management were determined. There were no deaths or serious morbidity in our series

Pulmonary embolism is a serious complication after arthroscopy of the knee, about which there is limited information. We have identified the incidence and risk factors for symptomatic pulmonary embolism after arthroscopic procedures on outpatients. The New York State Department of Health Statewide Planning and Research Cooperative System database was used to review arthroscopic procedures of the knee performed on outpatients between 1997 and 2006, and identify those admitted within 90 days of surgery with an associated diagnosis of pulmonary embolism. Potential risk factors included age, gender, complexity of surgery, operating time defined as the total time that the patient was actually in the operating room, history of cancer, comorbidities, and the type of anaesthesia. We identified 374 033 patients who underwent 418 323 outpatient arthroscopies of the knee. There were 117 events of pulmonary embolism (2.8 cases for every 10 000 arthroscopies). Logistic regression analysis showed that age and operating time had significant dose-response increases in risk (p < 0.001) for a subsequent admission with a pulmonary embolism. Female gender was associated with a 1.5-fold increase in risk (p = 0.03), and a history of cancer with a threefold increase (p = 0.05). These risk factors can be used when obtaining informed consent before surgery, to elevate the level of clinical suspicion of pulmonary embolism in patients at risk, and to establish a rationale for prospective studies to test the clinical benefit of thromboprophylaxis in high-risk patients

Several experimental models have been used to produce intravascular fat embolism. We have developed a simple technique to induce fat embolism using corn oil emulsified with distilled water to form fatty micelles. Fat embolism was produced by intravenous administration of these fatty micelles in anaesthetised rats, causing alveolar oedema, haemorrhage and increased lung weight. Histopathological examination revealed fatty droplets and fibrin thrombi in the lung, kidney and brain. The arteriolar lumen was filled with fatty deposits. Following fat embolism, hypoxia and hypercapnia occurred. The plasma phospholipase A. 2. , nitrate/nitrite, methylguidanidine and proinflammatory cytokines were significantly increased. Mass spectrometry showed that the main ingredient of corn oil was oleic acid. This simple technique may be applied as a new animal model for the investigation of the mechanisms involved in the fat embolism syndrome

Aims. The aim of this study was to assess whether it is possible to predict the mortality, and the extent and time of neurological recovery from the time of the onset of symptoms and MRI grade, in patients with the cerebral fat embolism syndrome (CFES). This has not previously been investigated. Methods. The study included 34 patients who were diagnosed with CFES following trauma between 2012 and 2018. The clinical diagnosis was confirmed and the severity graded by MRI. We investigated the rate of mortality, the time and extent of neurological recovery, the time between the injury and the onset of symptoms, the clinical severity of the condition, and the MRI grade. All patients were male with a mean age of 29.7 years (18 to 70). The mean follow-up was 4.15 years (2 to 8), with neurological recovery being assessed by the Glasgow Outcome Scale and the Mini-Mental State Examination. Results. In all, seven who had early-onset CFES (< 24 hours), and a severe Takahashi grade on MRI, died. There was a significant association between the time of onset of neurological signs and mortality (p = 0.035). Mortality was also significantly associated with a severe Takahashi grade (p < 0.001). Among the 27 surviving patients, 26 (96.3%) recovered completely. One (3.7%) had a cognitive deficit. The mean time to recovery was 4.7 weeks (2 to 13), with late recovery aftereight eight weeks being recorded in three patients. Conclusion. There was a significantly increased rate of mortality in patients with CFES who had an early onset of symptoms and a severe grade on MRI. Complete neurological recovery can be expected in most patients with CFES who survive. Cite this article: Bone Joint J 2022;104-B(1):142–149

We studied 4253 patients undergoing primary joint replacement between November 2002 and November 2007, of whom 4060 received aspirin only as chemical prophylaxis; 46 were mistakenly given low molecular weight heparin initially, which was stopped and changed to aspirin; 136 received no chemoprophylaxis and 11 patients received warfarin because of a previous history of pulmonary embolism. We identified the rate of clinical thromboembolism before and after discharge, and the mortality from pulmonary embolism at 90 days. The overall death rate was 0.31% (13 of 4253) and the rate of fatal pulmonary embolism was 0.07% (3 of 4253). Our data suggest that fatal pulmonary embolism is not common following elective primary joint replacement, and with modern surgical practice elective hip and knee replacement should no longer be considered high-risk procedures

We report a case of fatal pulmonary embolism following a simple ankle fracture in a 17-year-old girl. The diagnosis was confirmed at post-mortem. The risk factors for deep venous thrombosis and pulmonary embolism and their significance in orthopaedic fracture management are discussed

1. Blood from forty-one healthy volunteers, seventy-one patients with fractures but without symptoms of fat embolism and seven patients with clinical evidence of fat embolism was examined microscopically for fat droplets and chemically for triglycerides. 2. Fat droplets, after Millipore filtration of the blood, were seen evenly distributed in all three groups. 3. There was no significant difference in triglyceride concentration between serum and filtrate in the three groups. 4. The results do not support the thesis that the Gurd test is a reliable aid in the diagnosis of fat embolism

Intraoperative pulmonary fat and bone-marrow embolism is a serious complication of bone and joint surgery. We have investigated the occurrence and incidence of intraoperative embolism in patients undergoing elective lumbar spinal surgery with or without instrumentation. Sixty adult patients with lumbar degenerative disease were examined by intraoperative transoesophageal echocardiography while undergoing posterior lumbar surgery. Of these, 40 underwent surgery with instrumentation and 20 without. Moderate to severe (grade 2 or 3 according to the grading scale of Pitto et al) embolic events were seen in 80% of the instrumented patients but in none of the non-instrumented patients (p < 0.001). The insertion of pedicle screws was particularly associated with large numbers of pulmonary emboli, while the surgical approach, laminectomy, disc removal and bone harvesting were associated with small numbers of emboli. We consider that, as in arthroplasty and intramedullary fixation of fractures, these embolic events are relevant to the development of potentially fatal fat embolism during spinal surgery

1. A distinction must be made between the fat embolism syndrome, a clinical entity, and fat embolism demonstrated pathologically, which may be found after death following fracture with no prior evidence of the syndrome. 2. One hundred cases of the syndrome encountered over a period of four years have been studied in detail and the diagnostic criteria have been defined. These include one major feature, four minor features and fat macroglobulaemia. 3. Sixteen of the patients died–eight from severe pulmonary insufficiency of the syndrome, eight from other traumatic causes. 4. The prevention of shock is the best measure for prevention of the syndrome. The role of proteases in the production of shock and the place of protease inhibition in treatment of the syndrome are briefly discussed. 5. For the established case the aim of treatment is to ensure an adequate pressure of arterial oxygen

1. Reports of the lipaemia-clearing effect of heparin suggested that this drug might be of therapeutic value in fat embolism. 2. In an experimental trial with rats, heparin was found both to accelerate death and to increase the number of deaths after fat embolism. 3. It is accordingly concluded that a clinical trial of heparin in human fat embolism would not be warranted

We made a prospective study of the incidence of fatal pulmonary embolism in patients after total knee replacement with no prophylactic anticoagulation. There were 499 consecutive patients having 527 knee replacements. They all wore anti-thromboembolic stockings and were mobilised 48 hours after surgery. No patient was lost to follow-up. One patient died of pulmonary embolism 22 days after operation. There were no other deaths within three months of operation. The incidence of fatal pulmonary embolism was 0.19% (95% confidence interval: 0 to 0.6%). Fatal pulmonary embolism is rare after total knee replacement without prophylactic anticoagulation and the routine anticoagulation of these patients is of doubtful value

1. Fat embolism occurs in a high percentage of all cases of injury and it is a relatively frequent complication of fractures of the long bones in civilian accidents as well as battle casualties. 2. The diagnosis can usually be established by the clinical features together with certain physical signs which must however be sought deliberately. 3. Important clinical features are the mental disturbance, alternation of coma with full consciousness, petechial haemorrhages in the conjunctiva and skin, and typical changes in the retina. 4. Evidence is still conflicting as to whether the fat arises by embolism from an injured bone, or by general metabolic disturbance. 5. The fat is harmful not so much by reason of mechanical obstruction of vessels as by erosion and rupture of the vessel wall clue to the liberation of fatty acids. 6. Preventive treatment appears to be of some value but no satisfactory specific treatment is yet available for the established case. 7. Ligation of the profunda vein has been tried in two patients, one of whom recovered and the other died

The changes in a number of haemostatic factors after fractures of the tibia or femur were compared with those observed in patients with fat embolism complicating such fractures. After fractures uncomplicated by fat embolism there was a rise in the fibrinogen, α. 1. -antitrypsin and serum activation inhibitor. The plasminogen level and platelet count initially fell, but later increased to above the initial levels. Patients whose fractures were complicated by fat embolism had the same pattern of changes but quantitatively greater

Aims. The place of thromboprophylaxis in arthroplasty surgery remains controversial, with a challenging requirement to balance prevention of potentially fatal venous thrombo-embolism with minimising wound-related complications leading to deep infection. We compared the incidence of fatal pulmonary embolism in patients undergoing elective primary total hip arthroplasty (THA) between those receiving aspirin, warfarin and low molecular weight heparin (LMWH) for the chemical component of a multi-modal thromboprophylaxis regime. Patients and Methods. A prospective audit database was used to identify patients who had died within 42 and 90 days of surgery respectively between April 2000 and December 2012. A case note review was performed to ascertain the causes of death. Results. During this period 7983 THAs were performed. The rate of mortality was 0.43% and 0.58% at 42 and 90 days respectively. The groups comprised 1571 patients (19.7%) on warfarin, 1838 (23.0%) on LMWH and 4574 (57.3%) on aspirin. The 90-day mortality for these three groups was 0.38%, 1.09% and 0.43% respectively. The higher mortality rate for LMWH was significant (p < 0.05). There were six fatal pulmonary emboli (PEs) (0.08%). A total of three occurred within 42 days, all in the LMWH group. A total of three occurred between 42 and 90 days; one on warfarin, two on LMWH. The leading causes of death in all three groups were lower respiratory tract infections and myocardial infarction. Conclusion. We confirmed that fatal PE following elective THA with a multi-modal prophylaxis regime is rare. We further found that LMWH conferred no benefit over aspirin in this context, and is associated with a higher all-cause rate of mortality. Take home message: This study proposes that aspirin may be an appropriate thromboprophylaxis agent when used as part of a multi-modal regimen, suggesting current guidelines should be reviewed. Cite this article: Bone Joint J 2016;98-B:585–8

1. Three cases of acute peptic ulceration are reported after cerebral fat embolism complicating skeletal injuries. In two instances death occurred after perforation of an ulcer, and in the third intestinal haemorrhage led to death. 2. Although intracranial lesions and peptic ulceration have been reported on many occasions, so far as we know cerebral fat embolism as a cause has not been previously recognised. 3. The possible pathogenesis is discussed

1. A diagnostic procedure is described which is specific for fat embolism. It allows identification of the pathological fat globules On a stained slide. 2. The amount of pathological fat can be estimated by comparing the serum triglyceride levels before and after filtration. 3. The method is simple, reproducible and inexpensive

An episode of hypotension is common during cemented joint replacement, and has been associated with circulatory collapse and sudden death. We studied the mechanism of hypotension in two groups of six dogs after simulated bilateral cemented arthroplasty. In one group, with no lavage, the insertion of cement and prosthesis was followed by severe hypotension, elevated pulmonary artery pressure, decreased systemic vascular resistance and a 21% reduction in cardiac output. In the other group, pulsatile intramedullary lavage was performed before the simulated arthroplasties. Hypotension was less, and although systemic vascular resistance decreased, the cardiac output did not change. The severity of the hypotension, the decrease in cardiac output and an increase in prostaglandin metabolites were related to the magnitude of pulmonary fat embolism. Pulsatile lavage prevents much of this fat embolism, and hence the decrease in cardiac output. The relatively mild hypotension after lavage was secondary to transient vasodilation, which may accentuate the hypotension caused by the decreased cardiac output due to a large embolic fat load. We make recommendations for the prevention and management of hypotension during cemented arthroplasty

A case of fatal air embolism after Küntscher nailing of a fractured femur is described. Necropsy indicated that the only possible means of air entry was through the bone marrow. Subsequent discussion between the surgeon and the pathologist indicated that air must have been forced into the venous circulation through the marrow by repeated removal and reinsertion of nails, which allowed air to fill the punched-out marrow space when the nail was removed, the same air being forced into the marrow sinusoids when the nail was reinserted and hammered into position. This danger may be overcome 1) by allowing the site of operation to flood with blood by placing the patient in a "head up" position; 2) by flooding the operation site with saline; or 3) by assessing the calibre of nail required by radiological means rather than by trial and error

We carried out a prospective, randomised study of 62 patients to determine the efficacy of a foot sole pump (the A-V Impulse System) for the prevention of pulmonary embolism (PE) after hip surgery. PE was assessed by pulmonary perfusion scintigraphy before and after operation. We defined a PE as any new scintigraphic defect which was larger than a bronchopulmonary segment. The incidence of PE was 55% in the control group and 21% in the treatment group. The foot sole pump significantly reduced the incidence of PE (p = 0.008) and we encountered no side-effects from its use