Fracture Management in Chronic Kidney Disease: Challenges and Considerations for Orthopedic Surgeons.

Orthopedic surgeons treating fractures need to consider comorbidities, including chronic kidney disease (CKD), which affects millions worldwide. CKD patients are at elevated risk of fractures due to osteoporosis, especially in advanced stages. In addition, fractures in CKD patients pose challenges due to impaired bone healing and increased post-fracture complications including surgical site infection and nonunion. In this article, we will discuss factors that must be considered when treating fractures in CKD patients. Perioperative management includes careful adjustment of hemodialysis schedules, selection of anesthetic methods, and addressing bleeding tendencies. Tourniquet usage for fractures in limbs with arteriovenous fistulae should be cautious. Pain medication should be administered carefully, with opioids like hydromorphone preferred over nonsteroidal anti-inflammatory drugs. Medical management after fractures should address underlying factors and include physical rehabilitation to reduce the risk of subsequent fractures. A comprehensive approach to fracture management in CKD patients can improve outcomes.

Bleeding Control Protections Within US Good Samaritan Laws.

INTRODUCTION: In the United States, all 50 states and the District of Columbia have Good Samaritan Laws (GSLs). Designed to encourage bystanders to aid at the scene of an emergency, GSLs generally limit the risk of civil tort liability if the care is rendered in good faith. Nation-wide, a leading cause of preventable death is uncontrolled external hemorrhage. Public bleeding control initiatives aim to train the public to recognize life-threatening external bleeding, perform life-sustaining interventions (including direct pressure, tourniquet application, and wound packing), and to promote access to bleeding control equipment to ensure a rapid response from bystanders. METHODS: This study sought to identify the GSLs in each state and the District of Columbia to identify what type of responder is covered by the law (eg, all laypersons, only trained individuals, or only licensed health care providers) and if bleeding control is explicitly included or excluded in their Good Samaritan coverage. RESULTS: Good Samaritan Laws providing civil liability qualified immunity were identified in all 50 states and the District of Columbia. One state, Oklahoma, specifically includes bleeding control in its GSLs. Six states - Connecticut, Illinois, Kansas, Kentucky, Michigan, and Missouri - have laws that define those covered under Good Samaritan immunity, generally limiting protection to individuals trained in a standard first aid or resuscitation course or health care clinicians. No state explicitly excludes bleeding control from their GSLs, and one state expressly includes it. CONCLUSION: Nation-wide across the United States, most states have broad bystander coverage within GSLs for emergency medical conditions of all types, including bleeding emergencies, and no state explicitly excludes bleeding control interventions. Some states restrict coverage to those health care personnel or bystanders who have completed a specific training program. Opportunity exists for additional research into those states whose GSLs may not be inclusive of bleeding control interventions.

Life Over Limb: Why Not Both? Revisiting Tourniquet Practices Based on Lessons Learned From the War in Ukraine.

The use of tourniquets for life-threatening limb hemorrhage is standard of care in military and civilian medicine. The United States (U.S.) Department of Defense (DoD) Committee on Tactical Combat Casualty Care (CoTCCC) guidelines, as part of the Joint Trauma System, support the application of tourniquets within a structured system reliant on highly trained medics and expeditious evacuation. Current practices by entities such as the DoD and North Atlantic Treaty Organization (NATO) are supported by evidence collected in counter-insurgency operations and other conflicts in which transport times to care rarely went beyond one hour, and casualty rates and tactical situations rarely exceeded capabilities. Tourniquets cause complications when misused or utilized for prolonged durations, and in near-peer or peer-peer conflicts, contested airspace and the impact of high-attrition warfare may increase time to definitive care and limit training resources. We present a series of cases from the war in Ukraine that suggest tourniquet practices are contributing to complications such as limb amputation, overall morbidity and mortality, and increased burden on the medical system. We discuss factors that contribute to this phenomenon and propose interventions for use in current and future similar contexts, with the ultimate goal of reducing morbidity and mortality.

The Use of Tourniquets in the Russo-Ukrainian War.

AIM: The objective of the study was to evaluate the use of tourniquets in the Russo-Ukrainian war. METHODS: The type, number, and duration of tourniquets per limb, the clinical course of limb injuries, and the functional status of the injured limbs during the 24 hours post-injury were evaluated in military hospital facilities for the period of 2014-2022. Statistical frequencies and variances were analyzed. RESULTS: During active hostilities, the medical units of the Southern Operational Command received 2,496 patients with limb injuries that required the application of tourniquets. Lower extremity injuries were predominantly observed (84.4%). A single tourniquet was used in 1,538 cases (61.6%), whereas two tourniquets were used in 533 (21.4%), and three tourniquets in 425 cases (17.0%). During the 2014- 2021 period, Esmarch's tourniquet was most commonly used. However, in 2022, it was mostly replaced by the Combat Application Tourniquet and similar systems (e.g., Sich, Dnipro). The duration of the tourniquet use ranged from 50 to 380 minutes (mean 205.9 [standard error 8.1] min), which prolonged ischemia in a significant number of cases. Limb amputations, mainly due to extensive necrosis, were performed in 92 cases (3.7%). In addition to 101 deaths (4.0% of patients), 11 cases of severe tourniquet syndrome were encountered. The limb was salvaged in 9 cases (81.8%). CONCLUSION: Prompt triage and evacuation of injured combatants can save affected limbs, even when the duration of tourniquet use exceeds 2 hours. Tourniquet syndrome can be prevented using a hemostatic tourniquet.

Intraoperative tourniquet-induced hyperthermia in a pediatric patient: a forgotten association -a case report.

BACKGROUND: The intraoperative use of tourniquets is associated with several complications, including hyperthermia. We present the first documented case of tourniquet-induced hyperthermia in a pediatric patient at our institution. CASE: A 5-year-old female with no past medical history underwent tendon release surgery for congenital talipes equinovarus under general anesthesia. Following inflation of a pneumatic tourniquet to a pressure of 250 mmHg on her left thigh, the patient experienced a gradual increase in body temperature. Despite the implementation of cooling measures, the temperature continued to increase until it plateaued. The hyperthermia gradually resolved upon deflation of the tourniquet. CONCLUSIONS: Tourniquet-induced hyperthermia should be considered as a potential cause of intraoperative hyperthermia, particularly in the absence of typical signs of malignant hyperthermia. Early recognition and appropriate management, including deflation of the tourniquet and implementation of cooling measures, are crucial for preventing potential complications associated with hyperthermia.

A systematic review of tourniquet use in paediatric orthopaedic surgery: can we extrapolate from adult guidelines?

Purpose: Tourniquets are commonly used intraoperatively in orthopaedic surgery to control bleeding and improve visibility in the surgical field. Recent evidence has thrown into question the routine use of tourniquets in the adult population resulting in a British Orthopaedic Association standard for intraoperative use. This systematic review evaluates the evidence on the practice, benefits, and risks of the intraoperative use of tourniquets for trauma and elective orthopaedic surgery in the paediatric population. Methods: A prospectively registered systematic review was conducted using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (PROSPERO: CRD42022359048). A search of MEDLINE, Embase, the Cochrane Library and a Grey literature search was performed from their earliest record to 23 March 2023. Studies reporting tourniquet data in paediatric patients undergoing orthopaedic surgery were included. Data extracted included demographics, involved limb, trauma versus elective use, tourniquet use as primary or secondary measure, and tourniquet parameters and complications. Results: Thirty-nine studies were included. Tourniquet practices and information reporting varied considerably. Tourniquets were used uneventfully in the majority of patients with no specific benefits reported. Several physiological and biochemical changes as well as complications including nerve injury, compartment syndrome, skin burns, thrombosis, post-operative limb swelling, and pain were reported. Conclusions: Tourniquets are routinely used in both trauma and elective paediatric orthopaedic surgery with no high-quality research affirming benefits. Severe complications associated with their use are rare but do occur. High-quality studies addressing their benefits, the exact indication in children, and the safest way to use them in this population are necessary.

First aid and pre-hospital practices in snakebite victims: The persistent use of harmful interventions.

First aid intervention and pre-hospital (FAPH) practices are common in patients suffering from snakebite envenomation (SBE). In this study, we have reviewed the literature concerning the use of these practices in various regions of the world in the period 1947-2023 based on published prospective studies. A total of 71 publications fulfilled the inclusion criteria. In terms of the total number of patients in all studies that used each FAPH intervention, the most common practice was the application of tourniquets (45.8%). Other FAPH practices described include cuts/incisions (6.7%), the application of a variety of natural or synthetic substances at the bite site (5.6%), and ingestion of natural, usually herbal, remedies (2.9%). Washing the site of the bite was described in 9.1% of patients. There were other less frequent FAPH practices, including suction, splinting-immobilization, pressure-bandage, ice packs, application of a snake/black stone, and administration of alcoholic beverages. There were differences in the extent of application of FAPH interventions in different continents. Tourniquets were highest (55.7%) in Asia. Topical application of various products was common in South America, while pressure-bandage was only reported in Australia. We did not find any statistically significant variations in the frequency of the most frequent FAPH interventions at three-time intervals (before 2006, between 2006 and 2015, and after 2015). Our findings highlight the use of FAPH interventions in patients suffering SBE, some of which are known to be harmful. It is necessary to study these practices to a higher level of geographic granularity, using community-based surveys. Programs tailored to local contexts should be promoted, aimed at avoiding the use of harmful FAPH practices. It is also necessary to assess the efficacy and safety of some interventions through robust preclinical and clinical studies.

Extremity Tourniquet Self-Application by Antarctica Zodiac Crew Members.

Search and rescue teams and Antarctic research groups use protective cold-water anti-exposure suits (AES) when cruising on Zodiacs. Extremity tourniquet (ET) self-application (SA) donned with AESs has not been previously studied. Our study therefore assessed the SA of 5 commercial ETs (CAT, OMNA, RATS, RMT, and SWAT-T) among 15 volunteers who donned these suits. Tourniquet's SA ability, ease of SA, tolerance, and tourniquet preference were measured. All ETs tested were self-applied to the upper extremity except for the SWAT, which was self-applied with the rest to the lower extremity. Ease- of- SA mean values were compared using the Friedman and Durbin-Conover post hoc tests (P < 0.001). Regarding the upper extremity, OMNA achieved the highest score of 8.5 out of 10, while RMT, and SWAT received lower scores than other options (P < 0.001). For lower extremities, SWAT was found to be inferior to other options (P < 0.01). Overall, OMNA was the best performer. The RATS showed significantly lower tolerance than the other groups in repeated- measures ANOVA with a Tukey post hoc test (P < 0.01). Additionally, out of the 5 ETs tested, 60% of subjects preferred OMNA. The study concluded that SA commercial ETs are feasible over cold-water anti-exposure suits in the Antarctic climate.

Knowledge of stop the bleed techniques- a national survey.

OBJECTIVE: This article presents the dataset titled "Do you know how to Stop The Bleed®? [1]" The dataset contains the survey responses of 200 US persons aged 16 years and above regarding their knowledge of hemorrhage control, based on the American College of Surgeons Stop The Bleed® (STB) course [2]. RESULTS: Two hundred adults in the United States completed this web-based survey, which consisted of a quiz to assess STB knowledge. Factors that were not statistically correlated to STB knowledge retention included age, sex, race and education level up to college level. On the other hand, resuscitation coursework (p = 0.004) and income (p = 0.049) were important determinants of Stop the Bleed® knowledge. In particular, participants with CPR certification (p = 0.020) and/or a postgraduate degree (p = 0.015) scored higher than their counterparts in this sample cohort.

Effect of valproic acid upon skeletal muscle subjected to prolonged tourniquet application.

Background: Valproic acid (VPA), a histone deacetylase inhibitor, has shown improved outcomes when used as a pharmaceutical intervention in animal studies of hemorrhage, septic shock, and combined injuries. This study was designed to investigate the ability of VPA to mitigate ischemia-reperfusion injury produced by prolonged tourniquet application to an extremity. Methods: The ischemia-reperfusion model in anesthetized rats was established using hemorrhage and a 3-hour tourniquet application. VPA was administered intravenously prior to tourniquet wear and removal. Ischemia-reperfusion injury was evaluated by investigating pathway signaling, immune modulation of cytokine release, remote organ injury, and skeletal muscle function during convalescence. Results: We found that VPA sustained Protein kinase B (Akt) phosphorylation and Insulin-like growth factor signaling and modulated the systemic release of interleukin (IL)-1ß, tumor necrosis factor alpha, and IL-6 after 2 hours of limb reperfusion. Additionally, VPA attenuated a loss in glomerular filtration rate at 3 days after injury. Histological and functional evaluation of extremity skeletal muscle at 3, 7, and 21 days after injury, however, demonstrated no significant differences in myocytic degeneration, necrotic formation, and maximal isometric tetanic torque. Conclusions: Our results demonstrate that VPA sustains early prosurvival cell signaling, reduces the inflammatory response, and improves renal function in a hemorrhage with prolonged ischemia and reperfusion model. However, these do not translate into meaningful preservation in limb function when applied as a pharmaceutical augmentation to tourniquet wear. Level of evidence: IV.

Effect of dexmedetomidine on tourniquet-induced skeletal muscle injury

SUMMARY OBJECTIVE: The aim of this study was to investigate whether dexmedetomidine could reduce tourniquet-induced skeletal muscle injury. METHODS: C57BL6 male mice were randomly assigned to sham, ischemia/reperfusion, and dexmedetomidine groups. Mice in the ischemia/reperfusion and dexmedetomidine groups received normal saline solution and dexmedetomidine intraperitoneally, respectively. The sham group underwent the same procedure as the ischemia/reperfusion group, with the exception of tourniquet application. Subsequently, the ultrastructure of the gastrocnemius muscle was observed, and its contractile force was examined. In addition, Toll-like receptor 4 and nuclear factor-κB expression within muscles was detected by Western blot. RESULTS: Dexmedetomidine alleviated myocyte damage and increased the contractility of skeletal muscles. Moreover, dexmedetomidine significantly inhibited the expression of Toll-like receptor 4/nuclear factor-κB in the gastrocnemius muscle. CONCLUSION: Taken together, these results demonstrate that dexmedetomidine administration attenuated tourniquet-induced structural and functional impairment of the skeletal muscle, partly through inactivation of the Toll-like receptor 4/nuclear factor-κB pathway.

Impact of time and distance on outcomes following tourniquet use in civilian and military settings: A scoping review.

BACKGROUND: The last two decades have seen the reintroduction of tourniquets into guidelines for the management of acute limb trauma requiring hemorrhage control. Evidence supporting tourniquet application has demonstrated low complication rates in modern military settings involving rapid evacuation timeframes. It is unclear how these findings translate to patients who have prolonged transport times from injury in rural settings. This scoping review investigates the relationship between time and distance on metabolic complications, limb salvage and mortality following tourniquet use in civilian and military settings. METHODS: A systematic search strategy was conducted using PubMed, Embase, and SafetyLit databases. Study characteristics, setting, mechanism of injury, prehospital time, tourniquet time, distance, limb salvage, metabolic response, mortality, and tourniquet removal details were extracted from eligible studies. Descriptive statistics were recorded, and studies were grouped by ischemia time (< 2 h, 2-4 h, or > 4 h). RESULTS: The search identified 3103 studies, from which 86 studies were included in this scoping review. Of the 86 studies, 55 studies were primarily in civilian environments and 32 were based in military settings. One study included both settings. Blast injury was the most common mechanism of injury sustained by patients in military settings (72.8% [5968/8200]) followed by penetrating injury (23.5% [1926/8200]). In contrast, in civilian settings penetrating injury was the most common mechanism (47.7% [1633/3426]) followed by blunt injury (36.4% [1246/3426]). Tourniquet time was reported in 66/86 studies. Tourniquet time over four hours was associated with reduced limb salvage rates (57.1%) and higher mortality rates (7.1%) compared with a tourniquet time of less than two hours. The overall limb salvage and mortality rates were 69.6% and 6.7% respectively. Metabolic outcomes were reported in 28/86 studies with smaller sample sizes and inconsistencies in which parameters were reported. CONCLUSION: This scoping review presents literature describing comparatively safe tourniquet application when used for less than two hours duration. However, there is limited research describing prolonged tourniquet application or when used for protracted distances, such that the impact of tourniquet release time on metabolic outcomes and complications remains unclear. Prospective studies utilizing the development of an international database to provide this dataset is required.

Combined femoral artery block and femoral nerve block reduces thigh tourniquet-induced hypertension.

STUDY OBJECTIVE: Tourniquet hypertension (TH) is thought to be caused by sympathetically mediated C-fibers in the femoral epicardium following prolonged intraoperative inflation of the tourniquet, and we hypothesized that blocking the femoral artery at the same time as a conventional femoral nerve block would reduce the incidence of TH. DESIGN: A prospective, double-blind, randomized, controlled trial. SETTING: Operating room and hospital ward in the Third Hospital of Hebei Medical University. PATIENTS: A total of 72 patients receiving high tibial osteotomy under general anesthesia were recruited from June 2022 to September 2022. INTERVENTIONS: Patients were randomly assigned to receive either a classical femoral nerve block (CFNB) or a modified femoral nerve block (MFNB). Patients in the CFNB group received a 30 mL of 0.5% ropivacaine femoral nerve block and patients in the MFNB group received a 20 mL of 0.5% ropivacaine femoral nerve block combined with a 10 mL of 0.5% ropivacaine femoral artery block. MEASUREMENTS: The primary outcome assessed was the incidence of TH. Data on intraoperative esmolol dosage, analgesic effect, complications and hemodynamics during surgery were also recorded. MAIN RESULTS: Incidence of TH was significantly higher in the CFNB group compared with the MFNB group (71.88% vs 31.25%, P = 0.002). The systolic blood pressure in the CFNB group was significantly higher than that in the MFNB group at 45, 60, 75 and 90 min after tourniquet inflation (P = 0.029, P = 0.020, P = 0.009, P = 0.007). There was also a significant increase in intraoperative esmolol dosage in the CFNB group (65.63 ± 44.15 vs 22.19 ± 33.74, P < 0.001). Postoperative pain scores and patient satisfaction were not statistically significant between the two groups. CONCLUSIONS: The present study demonstrated that modified femoral nerve block reduced intraoperative esmolol dosage and the incidence of TH.

Extremity tourniquets raise blood pressure and maintain heart rate.

BACKGROUND: Tourniquets have been modified and used for centuries to occlude blood flow to control hemorrhage. More recently, the occlusion of peripheral vessels has been linked to resultant increases in blood pressure, which may provide additional therapeutic potential, particularly during states of low cardiac output. OBJECTIVE: The objective of this study was to investigate a causal relationship between tourniquet application and blood pressure in healthy adults. METHODS: Healthy adult volunteers were recruited to participate in this IRB-approved study. Each participant met inclusion criteria and demonstrated baseline normotension. Brachial cuff blood pressure and heart rate were recorded pre- and post-tourniquet application to the bilateral legs. RESULTS: Twenty-seven adults aged 22 to 35 years participated and were included in analysis. The average systolic blood pressure was 122 ± 7 mmHg, diastolic blood pressure was 72 ± 9 mmHg, and heart rate was 70 ± 13 bpm. Following bilateral tourniquet application over the femoral vasculature, we observed a statistically significant increase in systolic (7 mmHg, p < 0.001) and diastolic (4 mmHg, p = 0.05) blood pressures with no significant change in heart rate (2 bpm, p > 0.05). CONCLUSIONS: The elevations in systolic and diastolic blood pressures establish a dependent relationship between tourniquet application to the lower extremities and blood pressure elevation. These results may support new indications for tourniquet-use or extremity vessel occlusion in settings of hemodynamic instability.

Ensayo clínico para determinar si el momento de administración del ácido tranexámico en la cirugía de prótesis total de rodilla con torniquete influye en el sangrado perioperatorio / Clinical trial to determine whether the timing of tranexamic acid administration influences perioperative bleeding in total knee arthroplasty

Antecedentes y objetivos: El momento óptimo para la administración de ácido tranexámico en la artroplastia de rodilla con torniquete no está claro. El objetivo principal de nuestro estudio era demostrar si su administración tras la inducción anestésica reduce el sangrado postoperatorio respecto a administrarlo antes de la liberación del torniquete. Nuestro objetivo secundario era determinar si una segunda dosis reduce significativamente el sangrado. Material y métodos: Ensayo clínico prospectivo con 212 pacientes programados para prótesis total de rodilla, aleatorizados en 4 grupos. El ácido tranexámico se administró antes de la isquemia en los «grupos preinducción» (1 y 2) y justo antes de la liberación del torniquete en los «grupos preliberación» (3 y 4). Los grupos 2 y 4 recibieron una segunda dosis 3h después. La variable principal fue el sangrado postoperatorio (visible y el calculado). Las variables secundarias fueron la variación de hemoglobina, complicaciones y transfusión. Resultados: El sangrado total calculado fue 1563ml (IC 95%: 1445-1681) en los grupos preinducción frente a 1576ml (IC 95%: 1439-1713) en los preliberación (p=0,9); los de dosis única sangraron 1579ml (IC 95%: 1452-1706) frente a 1559ml (IC 95%: 1431-1686) en los de 2 dosis (p=0,82). La hemoglobina al alta fue 10,4 (IC 95%: 10,2-10,7) con una dosis frente a 10,8g/dl (IC 95%: 10,6-11,1) con 2 dosis (p=0,06). Conclusiones: No se detectaron diferencias en sangrado ni transfusión dependiendo del momento de administración del ácido tranexámico. Una segunda dosis tampoco tuvo impacto significativo.(AU)

Background and objectives: The ideal timing of tranexamic acid administration in total knee arthroplasty with tourniquet remains unclear. Our primary objective was to prove if administering it before surgical incision, instead of before releasing the tourniquet, reduces postoperative bleeding. A second objective was to determine whether a second dose reduces post-operative bleeding. Material and methods: A prospective, double-blind clinical trial was performed on 212 patients scheduled for total knee arthroplasty. They were randomised into 4 groups. Tranexamic acid was administered before the surgical incision in “pre-induction groups” (1 and 2), and just before the tourniquet release in “pre-release groups” (3 and 4). Groups 2 and 4 received a second dose 3hours post-surgery. Main outcome was postoperative bleeding (visible blood loss and calculated total bleeding). Secondary outcomes were haemoglobin variations, complications and transfusion rate. Results: The mean calculated total bleeding was 1563ml (95%CI: 1445 to 1681) in preinduction groups versus 1576ml (95%CI: 1439 to 1713) in pre-release groups (P=.9); 1579ml (95%CI: 1452 to 1706) in single-dose groups versus 1559ml (95%CI: 1431 to 1686) in double-dose groups (P=.82). One patient was transfused. The mean haemoglobin at discharge was 10.4g/dl (95%CI: 10.2 to 10.7) in singledose groups versus 10.8 (95%CI: 10.6 to 11.1) in double-dose groups (P=.06). Conclusions: There were no differences in bleeding or transfusion regarding the time of tranexamic acid administration. The second dose had not impact on outcomes.(AU)

Clinical trial to determine whether the timing of tranexamic acid administration influences perioperative bleeding in total knee arthroplasty.

BACKGROUND AND OBJECTIVES: The ideal timing of tranexamic acid administration in total knee arthroplasty with tourniquet remains unclear. Our primary objective was to prove if administering it before surgical incision, instead of before releasing the tourniquet, reduces postoperative bleeding. A second objective was to determine whether a second dose reduces post-operative bleeding. MATERIAL AND METHODS: A prospective, double-blind clinical trial was performed on 212 patients scheduled for total knee arthroplasty. They were randomised into 4 groups. Tranexamic acid was administered before the surgical incision in "pre-induction groups" (1 and 2), and just before the tourniquet release in "pre-release groups" (3 and 4). Groups 2 and 4 received a second dose 3h post-surgery. Main outcome was postoperative bleeding (visible blood loss and calculated total bleeding). Secondary outcomes were haemoglobin variations, complications and transfusion rate. RESULTS: The mean calculated total bleeding was 1563ml (95%CI: 1445-1681) in preinduction groups versus 1576ml (95%CI: 1439-1713) in pre-release groups (P=0.9); 1579ml (95%CI: 1452-1706) in single-dose groups versus 1559ml (95%CI: 1431-1686) in double-dose groups (P=0.82). One patient was transfused. The mean haemoglobin at discharge was 10.4g/dl (95%CI: 10.2-10.7) in singledose groups versus 10.8 (95%CI: 10.6-11.1) in double-dose groups (P=0.06). CONCLUSIONS: There were no differences in bleeding or transfusion regarding the time of tranexamic acid administration. The second dose had not impact on outcomes. TRIAL REGISTRATION: EudraCT 2016-000071-24.

Tourniquet use in patients undergoing tumour resection and endoprosthetic reconstruction of the knee.

AIMS: The aim of this study was to determine the prevalence and impact of tourniquet use in patients undergoing limb salvage surgery with endoprosthetic reconstruction for a tumour around the knee. METHODS: We retrieved data from the Prophylactic Antibiotic Regimens in Tumor Surgery (PARITY) trial; specifically, differences in baseline characteristics, surgical details, and postoperative functional outcomes between patients who had undergone surgery under tourniquet and those who had not. A linear regression model was created to evaluate the impact of tourniquet use on postoperative Toronto Extremity Salvage Scores (TESSs) while controlling for confounding variables. A negative-binomial regression model was constructed to explore predictors of postoperative length of stay (LOS). RESULTS: Of the 604 patients enrolled in the PARITY trial, 421 had tumours around the knee joint, of whom 225 (53%) underwent surgery under tourniquet. The tourniquet group was younger (p = 0.014), more likely to undergo surgery for a tumour of the tibia, and had shorter operating times by a mean of 50 minutes (95% confidence interval 30 to 72; p < 0.001). The adjusted linear regression model found that the use of a tourniquet, a shorter operating time, and a higher baseline TESS independently predicted better function at both three- and six-month follow-up. The negative-binomial regression model showed that tourniquet use, shorter operating time, younger age, and intraoperative tranexamic acid administration independently predicted a shorter LOS in hospital. CONCLUSION: The results of this study show that in patients undergoing resection of a tumour around the knee and endoprosthetic reconstruction, the use of an intraoperative tourniquet is associated with a shorter operating time, a reduced length of stay in hospital, and a better early functional outcome.Cite this article: Bone Joint J 2022;104-B(10):1168-1173.

Tourniquet use following blast-associated complex lower limb injury and traumatic amputation promotes end organ dysfunction and amplified heterotopic ossification formation.

BACKGROUND: Traumatic heterotopic ossification (tHO) is characterized by ectopic bone formation in extra-skeletal sites leading to impaired wound healing, entrapment of neurovascular structures, pain, and reduced range of motion. HO has become a signature pathology affecting wounded military personnel who have sustained blast-associated traumatic amputations during the recent conflicts in Iraq and Afghanistan and can compound recovery by causing difficulty with prosthesis limb wearing. Tourniquet use to control catastrophic limb hemorrhage prior to surgery has become almost ubiquitous during this time, with the recognition the prolonged use may risk an ischemia reperfusion injury and associated complications. While many factors influence the formation of tHO, the extended use of tourniquets to limit catastrophic hemorrhage during prolonged field care has not been explored. METHODS: Utilizing an established pre-clinical model of blast-associated complex lower limb injury and traumatic amputation, we evaluated the effects of tourniquet use on tHO formation. Adult male rats were subjected to blast overpressure exposure, femur fracture, and soft tissue crush injury. Pneumatic tourniquet (250-300 mmHg) applied proximal to the injured limb for 150-min was compared to a control group without tourniquet, before a trans-femoral amputation was performed. Outcome measures were volume to tHO formation at 12 weeks and changes in proteomic and genomic markers of early tHO formation between groups. RESULTS: At 12 weeks, volumetric analysis with microCT imaging revealed a 70% increase in total bone formation (p = 0.007) near the site of injury compared to rats with no tourniquet time in the setting of blast-injuries. Rats subjected to tourniquet usage had increased expression of danger-associated molecular patterns (DAMPs) and end organ damage as early as 6 h and as late as 7 days post injury. The expressions of pro-inflammatory cytokines and chemokines and osteochondrogenic genes using quantitative RT-PCR similarly revealed increased expression as early as 6 h post injury, and these genes along with hypoxia associated genes remained elevated for 7 days compared to no tourniquet use. CONCLUSION: These findings suggest that tourniquet induced ischemia leads to significant increases in key transcription factors associated with early endochondral bone formation, systemic inflammatory and hypoxia, resulting in increased HO formation.

Efficacy of leupeptin in treating ischemia in a rat hind limb model.

Prolonged tourniquet use can lead to tissue ischemia and can cause progressive muscle and nerve injuries. Such injuries are accompanied by calpain activation and subsequent Wallerian-like degeneration. Several known inhibitors, including leupeptin, are known to impede the activity of calpain and associated tissue damage. We hypothesize that employment of leupeptin in a rat model of prolonged hind limb ischemia can mitigate muscle and nerve injuries. Sprague-Dawley rats (n = 10) weighing between 300-400 g were employed in this study. Their left hind limbs were subjected to blood flow occlusion for a period of 2-h using a neonatal blood pressure cuff. Five rats were given twice weekly intramuscular leupeptin injections, while the other five received saline. After 2 weeks, the animals were euthanized, their sciatic nerves and gastrocnemius muscles were harvested, fixed, stained, and analyzed using NIH Image J software. The administration of leupeptin resulted in larger gastrocnemius muscle fiber cross-sectional areas for the right (non-tourniquet applied) hindlimb as compared to that treated with the saline (p = 0.0110). However, no statistically significant differences were found between these two groups for the injured left hindlimb (p = 0.1440). With regards to the sciatic nerve cross-sectional areas and sciatic functional index, no differences were detected between the leupeptin and control treated groups for both the healthy and injured hindlimbs. This research provides new insights on how to employ leupeptin to inhibit the degenerative effects of calpain and preserve tissues following ischemia resulting from orthopedic or plastic surgery procedures.

Prehospital extremity tourniquet placements-performance evaluation of non-EMS placement of a lifesaving device.

BACKGROUND: The education of civilians and first responders in prehospital tourniquet (PT) utilization has spread rapidly. We aimed to describe trends in emergency medical services (EMS) and non-EMS PT utilization, and their ability to identify proper clinical indications and to appropriately apply tourniquets in the field. METHODS: A retrospective cohort study was conducted to evaluate all adult patients with PTs who presented at two Level I trauma centers between January 2015 and December 2019. Data were collected via an electronic patient query tool and cross-referenced with institutional Trauma Registries. Medically trained abstractors determined if PTs were clinically indicated (limb amputation, vascular hard signs, injury requiring hemostasis procedure, or significant documented blood loss). PTs were further designated as appropriately or inappropriately applied (based on tourniquet location, venous tourniquet, greater than 2-h ischemic time). Descriptive statistics and univariate analyses were performed. RESULTS: 146 patients met inclusion criteria. The incidence of yearly PT placements increased between 2015 and 2019, with an increase in placement by non-EMS personnel (police, firefighter, bystander, and patient). Improvised PTs were frequently utilized by bystanders and patients, whereas first responders had high rates of commercial tourniquet use. A high proportion of tourniquets were placed without indication (72/146, 49%); however, the proportion of PTs placed without a proper indication across applier groups was not statistically different (p = 0.99). Rates of inappropriately applied PTs ranged from 21 to 46% across all groups applying PTs. CONCLUSIONS: PT placement was increasingly performed by non-EMS personnel. Present data indicate that non-EMS persons applied PTs at a similar performance level of those applied by EMS. Study LevelLevel III.