Background: Glenoid loosening is a well-documented failure mechanism in anatomic shoulder arthroplasty. Implant manufacturers have developed innovative designs to address these issues, with hybrid glenoid components emerging as a potential solution. This study investigates the Exactech Equinoxe glenoid (Exactech Inc., Gainesville, FL, USA), a hybrid component that has shown higher midterm revision rates in national registry data. Methods: We conducted an investigation of failed Equinoxe Cage Glenoid implants revised between November 2022 and July 2025 and analyzed at a tertiary arthroplasty retrieval center. Clinical data, radiographs, and intraoperative findings were reviewed. Radiographs were assessed for radiolucency (Lazarus score), implant position, and evidence of fracture or metallic debris. Retrieved components underwent macroscopic inspection and evaluation of wear modes. Polyethylene (PE) oxidation was quantified through white-banding assessment and Fourier Transform Infrared Spectroscopy. Periprosthetic tissues, when available, underwent inductively coupled plasma mass spectrometry to evaluate metal ion presence. Results: Eleven failed hybrid glenoid components were analyzed at a median of 5.8 years after implantation. Radiographic loosening was present in 82% of cases (median Lazarus score 5). All retrieved components demonstrated macroscopic PE wear; 82% showed cracking and delamination. Fourier Transform Infrared Spectroscopy confirmed subsurface oxidation in all tested components. Peripheral peg fixation was limited, with 100% of pegs demonstrating minimal bony ongrowth and 45% showing polishing consistent with micro-motion. In contrast, 100% of central metal cages exhibited bony ingrowth. Metal debris or staining was noted in 55% of cases, and tissue samples demonstrated elevated metal ions consistent with cage or peg wear. Conclusion: Failed Equinoxe Cage Glenoid implants demonstrated consistent patterns of PE oxidation and inadequate peripheral peg fixation, contributing to loosening and mechanical failure at the PE-metal interface. These findings provide a potential mechanism for the higher revision rate observed in national registry data and highlight the importance of ongoing postmarket surveillance of new implant designs.

Early tibial loosening has been reported in the Attune total knee arthroplasty (TKA) system, with uncertainty regarding the contribution of clinical, demographic, and implant-related factors. We retrospectively analyzed 130 retrieved Attune TKAs from 126 patients across nine institutions. Clinical and demographic data, reasons for revision, and implant features were collected. Cement coverage of 96 cemented tibial baseplates was quantified using digitized image analysis, and 15 polyethylene tibial bearings underwent mechanical and oxidation testing. Statistical significance was defined as p < 0.05. The mean time in situ was 2.0 years (range 0.1–8.3). Main reasons for revision were loosening (37.7

Background: Dual mobility (DM) implants in total hip arthroplasty provide excellent range of motion with low dislocation rates. A complication of this design is intraprosthetic dislocation (IPD), where the polyethylene (PE) liner dissociates from the femoral head. In older designs, IPD occurred due to a small head size and late PE wear with head-capture-mechanism failure. Routine retrieval analysis identified concerns regarding IPD of modern implants, and scant reporting in the literature led to this retrospective study. Methods: A total of 124 (110 primary, 14 revision) DM implants (mean in situ time 2.0 ± 3.1 years) revised by 20 surgeons across Western Australia between July 2014 and August 2023 were assessed. Demographics, clinical information, mechanisms of failure, and observations at revision arthroplasty were analyzed. The retrieval analysis included an assessment of metal and PE wear mechanisms, corrosion between modular components, and extent of bony attachment to acetabular shells. Results: There were 11 cases of IPD. Of these, 8 (73%) had a documented preceding failed closed reduction, with the remaining 3 revised due to trunnionosis, loosening, and joint instability. Nine out of 11 (82%) cases were female. Although metallic wear and inner-lip impingement of PE bearings were observed, there was no obvious failure mechanism for the other 3 retrieved IPD implants. Conclusions: Most cases of IPD in DM implants occur after failed closed reduction in the setting of a hip dislocation, suggesting an iatrogenic cause of IPD. No implant-related features could be defined for the remaining cases. Recognizing common failure modes can help with the prevention and treatment of this complication.

BACKGROUND:Synthetic grafts have been used for a number of years in anterior cruciate ligament (ACL) reconstruction surgery. One of the more recent additions to the stable of synthetic ligaments is the Ligament Augmentation and Reconstruction System (LARS) ligament. PURPOSE:To analyze the biomechanics and histology of LARS grafts retrieved due to failure of the device. STUDY DESIGN:Descriptive laboratory study. METHODS:A total of 22 LARS ligament grafts that were explanted from patients were sent for analysis. Five new, unused samples of the standard LARS ACL graft were also analyzed. Biomechanical testing was performed: ultimate tensile force, force versus displacement, and stress versus strain were recorded. Histopathological examination was performed looking for degree of fibrous tissue ingrowth as well as the presence of a foreign body reaction. RESULTS:Of the 22 grafts retrieved, 14 were used for ACL grafts, 1 for a lateral collateral ligament graft, 2 for medial collateral ligament grafts, 4 for gluteal tendon augmentation, and 1 for a supraspinatus augmentation. A severe foreign body reaction was found in 86% of the grafts (18/22) and a mild foreign body reaction in the remaining 14% (4/22). Tissue ingrowth was minimal in the majority of ACL grafts; the other grafts showed moderate tissue ingrowth. Maximal tensile force was significantly higher for the new ACL grafts (mean ± SD, 1667 ± 845 N) compared with the retrieved grafts (897 ± 395 N; P < .05). CONCLUSION:This study demonstrated that the vast majority of retrieved LARS artificial ligaments had a florid foreign body reaction. There was minimal tissue ingrowth in ACL grafts and moderate ingrowth in other grafts. Retrieved grafts had a decreased ultimate tensile force, which increased their risk of rupture. CLINICAL RELEVANCE:Surgeons should be cautious in choosing to use these grafts in reconstructive surgery for patients.

PURPOSE:To assess the variability in graft biomechanical properties of an acellular human dermal matrix patch. METHODS:A total of 22 strips obtained from 6 separate graft specimens (AlloPatch HD) were tested. Load elongation properties after cyclic loading, including ultimate load at break, energy at break, and extension at break, were tested and compared by graft thickness. Suture pull-out testing using a simple vertical stitch suture retention test was performed. RESULTS:There was a significant, strong positive correlation between graft thickness and ultimate load to failure, energy at break, and extension at break (P < .01). The association between direction of graft in relation to skin tension lines and ultimate load to failure was also significant (P < .034). The difference in ultimate load to failure from the extremes of graft thickness in this study (1.1 mm vs 3.2 mm) was almost 4-fold (104 N/mm2 vs 402 N/mm2). The suture pull-out testing of 10 dermal graft test strips showed that once the graft thickness reached a threshold thickness of 2 mm, the mode of failure changed from cutting through the graft vertically to tearing the graft diagonally. CONCLUSIONS:The tested dermal allograft patch shows great variability in thickness within and between individual patches. This study has revealed that grafts thicker than 2 mm and those used in parallel to skin tension lines exhibit a higher ultimate load to failure. Furthermore, graft thickness over 2 mm influenced the method of suture failure. CLINICAL RELEVANCE:Caution should be exercised when using grafts less than 2 mm due to lower ultimate load to failure and suture pull-out. Marking the patches in accordance with skin tension lines would help determine the ideal orientation of insertion.

Background: Fretting corrosion at modular junctions contributes to arthroplasty failure. Currently, no evidence-based guidelines are available regarding the acceptable level of trunnion corrosion that can occur in vivo. We aimed to examine the relationship between trunnion corrosion and risk of re-revision to assist surgeons with intraoperative decision making. Method: Grading by 3 independent examiners of revised and re-revised head components was performed using a modified Goldberg corrosion scale. Samples were separated into low-grade (LG) and high-grade (HG) corrosion. Mechanical testing determined the relationship between corrosion severity and pull-off strength at the head-stem junction. Results: 529 retrieved femoral heads were analysed. A positive association was detected between males and HG corrosion (OR 2.07; 95% CI, 1.45–2.94; p < 0.001). No difference between the survivorship of LG and HG heads was detected ( p-value = 0.247). In the re-revised sample, the first implant had a time in situ that was on average 7.97 years longer (95% CI, 5.4–10.6) than that of the subsequent re-revised femoral head. Severe corrosion on the first head was associated with a 37.5 (95% CI, 4.00–1944) fold increase of HG on the subsequent head ( p < 0.001). Femoral disassembly force had a positive correlation with stem taper corrosion grade ( p = 0.001). Conclusions: A well-fixed stem with corrosion may remain in situ.

A face shield is a secondary personal protective equipment (PPE) for healthcare workers (HCW). Worn with the appropriate face masks/respirators, it provides short term barrier protection against potentially infectious droplet particles. Coronavirus disease 2019 (COVID-19) caused a spike in demand for PPE, leading to a shortage and risking the safety of HCW. Transport restrictions further challenged the existing PPE supply chain which has been reliant on overseas-based manufacturers. Despite the urgency in demand, PPE must be properly tested for functionality and quality. We describe the establishment of local face shields manufacture in Western Australia to ensure adequate PPE for HCW. Ten thousand face shields for general use (standard) and for ear, nose and throat (ENT) specialist use were produced. Materials and design considerations are described, and the face shields were vigorously tested to the relevant Standards to ensure their effectiveness as a protective barrier, including splash and impact resistance. Comparative testing with traditional and other novel face shields was also undertaken. Therapeutic Goods Administration (TGA) licence was obtained to manufacture and supply the face shields as a Class I medical device. The swiftness of process is a credit to collaboration from industry, academia and healthcare.

Background: Although the Pinnacle Acetabular Hip System (DePuy Synthes) has demonstrated excellent survivorship results since it was first introduced in 2003, there have been a growing number of cases indicating that Pinnacle liners may be subject to a higher-than-expected rate of early dissociation failure. Between 2006 and 2020, our Centre received 212 retrieved Pinnacle liners from Western Australian hospitals. Of these, 26 were removed due to liner dissociation. Methods: To better understand the frequency and cause of this complication we assessed all retrieved Pinnacle acetabular components for type, damage modes and patient demographics. The leverage force required to dissociate Pinnacle liners was also measured and compared with another commonly used acetabular system, the Trident (Stryker Orthopaedics). Results: The estimated minimum incidence of liner dissociation from our data was 0.35%. Characterisation of dissociated Pinnacle cases (n = 26) revealed 73% were female with an average age of 59 compared to all retrieved Pinnacle cases (n = 212) where 58% were female with an average age of 66. Retrieval analysis indicated plastic deformation of the liner into an ovoid shape, signs of impingement on the rim postero-superiorly and shearing of the liner’s anti-rotation tabs was common. Mechanical testing indicated that the dissociation strength of Pinnacle cups decreases at approximately 6.6 N/year in situ (p = 0.01). Conclusion: The survival rate of Pinnacle acetabular cups is exceptional with only 5% revised at 10 years. However, surgeons should be aware of the clinical symptoms and high-risk demographics when assessing patients with polyethylene Pinnacle liners.

OBJECTIVE:In the present study, we investigated the structural integrity of inferior vena cava (IVC) filters after their retrieval. METHODS:A prospective ex vivo biomechanical analysis was performed of the structural integrity of 100 IVC filters used in a randomized controlled trial to evaluate the effectiveness of prophylactic IVC filters in preventing mortality or symptomatic pulmonary embolism in major trauma patients. RESULTS:Of the 100 included patients, 7 (7%) had required more than one attempt to remove the filter. The median duration of the filter left in situ was 54 days (interquartile range, 17-101 days). During the initial attempt to remove six filters (6%), thrombi were found entrapped and required 4 weeks of systemic anticoagulation therapy before the filters could be removed in a second attempt. A positive correlation was found between the duration of the filter left in situ and the loss in metallic elasticity of the nitinol alloy of the filter struts (Pearson correlation coefficient, 0.232; P = .008). One filter was adherent to the IVC wall and required open surgical removal 227 days after its initial placement. One of the six long struts of the filter had been fractured during the removal process, with evidence of hardening to bending stress in the remaining five struts of the fractured filter compared with the struts of the 25 intact filters. Fibrous endothelial tissue (73%) and thrombi (33%) adherent to the retrieved filters were frequently observed. The presence of adherent fibrous tissue was not significantly related statistically to the duration of the filter left in situ (P = .353) but was more common among the patients who had had a delay in receiving prophylactic anticoagulation therapy (mean difference, 2 days; 95% confidence interval, 0.6-3.3; P = .039). CONCLUSIONS:Metallic fatigue might account for IVC filter strut fractures. Fibrous endothelial tissue adherent to the filters was common, especially for those with a delay in receiving prophylactic anticoagulation therapy.

A new method was developed to study the complex corrosion mechanism found in modular hip arthroplasty, i.e., dynamic crevice corrosion. Short wear events followed by rest times were applied in a conformal tribocontact to simulate different activity levels. Likewise, stepped potentiostatic polarization testing and electron microscopy were used to compare dynamic (continuous and interrupted) and static conditions. Results showed that 316L stainless steel underwent severe corrosion under the dynamic setting. The findings reproduced the extent and morphology of attack found in a retrieved implant. Thus, the new method could be used to investigate the corrosion susceptibility of modular hip arthroplasty.

Background: The SCORE total knee arthroplasty (Amplitude, France) has a deep trochlear groove designed to reduce polyethylene wear, risk of loosening, and patellofemoral complications. In 2014, the AOANJRR reported a higher revision rate when implanted cementless compared to cemented. The aim of the study was to forensically examine retrieved SCORE TKA’s and determine failure modes. Methods: Retrieval analysis was performed at the Centre of Implant Technology and Retrieval Analysis (Royal Perth Hospital). 27 SCORE primary total knee implants from 26 patients requiring revision were forensically analysed for failure mode. Macroscopic examination and quantitative assessment of tissue ingrowth was combined with clinical record findings and radiographic analysis. Statistical analysis was performed. Results: On average the patients were relatively young (mean age 65.5 years) and obese (mean BMI=32.5) with almost equal numbers of male and females and a mean short time of service (2.4 years). The majority of the implants were cementless and without patella resurfacing. Secondary analysis of patient demographics found no difference in age, BMI, gender and activity levels between the patients with loose femoral components and the population as a whole. Radiological analysis revealed an overall satisfactory alignment using the Knee Society TKA Roentgenographic Evaluation and Scoring System. Although six uncemented femoral components (22%) were found grossly loose at time of revision, only one was identified pre-operatively from plain x-rays. Macroscopic analysis confirmed coating delamination and deposition of fine metallic debris on tissue attached to components. Polyethylene inserts had a degree of wear greater than expected with embedded metal debris. Histomorphometric analysis revealed poor bony ingrowth on both uncemented femoral and tibial components. Conclusions: Retrieval analysis revealed a higher than expected rate of cementless femoral loosening in SCORE TKAs. Clinically, surgeons should be aware of patients with this implant presenting with pain that femoral loosening cannot be excluded as a diagnosis by imaging.

Tuneable, bioactive hydrogels present an attractive option as cell-instructive substrates for tissue regeneration. Properties mimicking the extracellular matrix at the site of injury are sought after, in particular the ability to regulate growth factors that are key to the regeneration process. This study demonstrates the successful formation of hydrogels with heparin functionalities and fibroblast growth factor-2 (FGF-2). Poly(2-hydroxyethyl methacrylate)-heparin hydrogels were capable of retaining FGF-2 by specific binding to heparin and subsequently showed sustained presentation of the growth factor to mesenchymal stromal cells (MSC). Heparin acted as stable anchoring molecules for FGF-2 on the substrate and the synergistic effect of the ensuing heparin-FGF-2 complex was evident in supporting long term cell growth. The presence of heparin during 3D scaffold formation was also found to introduce surface roughness and microporosity to the resulting hydrogels. While FGF-2 has been known to encourage MSC growth and maintain their multilineage potential, other heparin-binding ligands such as bone morphogenetic proteins are potent differentiation stimuli for MSC. Therefore preserving MSC multipotency or a push toward a differentiation pathway may be pursued by the choice of ligand applied to and bound by the heparin functionalities on the current substrate.

BackgroundWhether early placement of an inferior vena cava filter reduces the risk of pulmonary embolism or death in severely injured patients who have a contraindication to prophylactic anticoagulation is not known. MethodsIn this multicenter, randomized, controlled trial, we assigned 240 severely injured patients (Injury Severity Score >15 [scores range from 0 to 75, with higher scores indicating more severe injury]) who had a contraindication to anticoagulant agents to have a vena cava filter placed within the first 72 hours after admission for the injury or to have no filter placed. The primary end point was a composite of symptomatic pulmonary embolism or death from any cause at 90 days after enrollment; a secondary end point was symptomatic pulmonary embolism between day 8 and day 90 in the subgroup of patients who survived at least 7 days and did not receive prophylactic anticoagulation within 7 days after injury. All patients underwent ultrasonography of the legs at 2 weeks; patients also underwent mandatory computed tomographic pulmonary angiography when prespecified criteria were met. ResultsThe median age of the patients was 39 years, and the median Injury Severity Score was 27. Early placement of a vena cava filter did not result in a significantly lower incidence of symptomatic pulmonary embolism or death than no placement of a filter (13.9% in the vena cava filter group and 14.4% in the control group; hazard ratio, 0.99; 95% confidence interval [CI], 0.51 to 1.94; P=0.98). Among the 46 patients in the vena cava filter group and the 34 patients in the control group who did not receive prophylactic anticoagulation within 7 days after injury, pulmonary embolism developed in none of those in the vena cava filter group and in 5 (14.7%) in the control group, including 1 patient who died (relative risk of pulmonary embolism, 0; 95% CI, 0.00 to 0.55). An entrapped thrombus was found in the filter in 6 patients. ConclusionsEarly prophylactic placement of a vena cava filter after major trauma did not result in a lower incidence of symptomatic pulmonary embolism or death at 90 days than no placement of a filter.

Background: Mechanical failure of intramedullary nails is rare. This investigation was prompted by a series of cases of observed breakage of the recently introduced TFNA Proximal Femoral Nailing System (TFN [Trochanteric Fixation Nail]-Advanced; DePuy Synthes) in our region. Laboratory analysis and case data are presented, in contribution to post-market surveillance. Methods: Medical and imaging records from the 3 public tertiary orthopaedic trauma hospitals in Western Australia were reviewed. Relevant data of patients in whom breakage of the TFNA implant occurred between 2016 and 2018 were collected and analyzed. Laboratory review of retrieved implants was conducted at the Centre for Implant Technology and Retrieval Analysis (CITRA) in Western Australia. Results: A total of 16 cases of TFNA implant breakage were recorded and analyzed. The predominant OTA/AO fracture classification was 31A3 (12 cases, 75%). The reduction quality was good in 10 cases, acceptable in 4 cases, and poor in 2 cases. The mean time to failure (and standard deviation) was 5.0 ± 2.2 months (range, 2.2 to 9.8 months). The treatment modality for the breakage was revision nailing in 11 cases, arthroplasty in 3, and nonoperative management in 2. All nails broke at the proximal screw aperture, with 1 nail additionally breaking at the distal aperture. Of 8 patients treated with a second TFNA implant for nail breakage, 3 (38%) returned with breakage of the revision implant. Laboratory analysis of the broken nails demonstrated a unique fracture pattern, with a stepped propagation pathway. Conclusions: This study represents the largest series, to our knowledge, of proximal femoral nail breakages in the published English literature and is the first that we are aware of to involve laboratory analysis of the TFNA implant. Changes to the nail design and/or alloy may have contributed to the observed cases of breakage, and this study will be followed by an evaluation of breakage rates in comparison with those of previous generations of nailing systems. We advise close clinical and radiographic surveillance of patients with unstable hip fracture patterns who undergo osteosynthesis with use of a TFNA implant. Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

AIMS The aim of this study was to conduct the largest low contact stress (LCS) retrieval study to elucidate the failure mechanisms of the Porocoat and Duofix femoral component. The latter design was voluntarily recalled by the manufacturer. MATERIALS AND METHODS Uncemented LCS explants were divided into three groups: Duofix, Porocoat, and mixed. Demographics, polyethylene wear, tissue ingrowth, and metallurgical analyses were performed. RESULTS In 104 implants, a decrease in the odds of loosening and an increase in metallosis and tissue staining in the Duofix group relative to Porocoat group was detected (p = 0.028). There was an increased presence of embedded metallic debris in the Duofix group (p < 0.001). Decreased tissue ingrowth was associated with the Duofix surface (p < 0.001). The attached beads had reduced microhardness, indicative of adverse thermal processing, which resulted in bead shedding, particulate debris, and metallosis. CONCLUSION Hydroxyapatite coating of the LCS femoral component produced unexpected results and led to its recall. The root cause was likely a combination of retained alumina grit and a reduction in bead microhardness (mechanical strength) resulting in increased particle debris, metallosis, and early revision. The Duofix LCS femoral component was not equivalent to the Porocoat version despite its approval through the Food and Drug Administration (FDA) 510(k) equivalance approval process. Regulation of the introduction of modified existing devices needs to be improved and the Duofix LCS should have been considered to be a new device for which equivalence had not been demonstrated at the point of introduction. Cite this article: Bone Joint J 2019;101-B:1248-1255.

BACKGROUND:Artificial ligaments have been developed and used in the treatment of ligamentous injuries since the 1970s. The early generation of artificial ligaments showed promising short-term results but resulted in high rates of rupture and inflammatory reaction in the surrounding tissues. PURPOSE:To determine whether the use of Ligament Augmentation and Reconstruction System (LARS) ligaments is associated with the development of intra-articular foreign body reaction. STUDY DESIGN:Case series; Level of evidence, 4. METHODS:LARS ligaments were explanted from 15 patients under 6 consultant orthopaedic surgeons at 8 surgical centers. Of these, 14 explanted samples were sent for macroscopic and histological analysis, with the 1 remaining sample sent for scanning electron microscopy, to assess for inflammatory change as well as the degree of fibrous tissue ingrowth. RESULTS:We observed a foreign body reaction in 10 of 14 explanted LARS ligaments. Seven samples demonstrated fibrous tissue ingrowth, with 5 producing only focal or incomplete ingrowth. The 2 samples with extensive fibrous coverage were completely free of any foreign body reaction, while all 5 remaining samples with only focal or partial fibrous ingrowth were associated with at least some degree of harmful immune response. CONCLUSION:The LARS ligament is still associated with a clinically significant degree of foreign body reaction despite the LARS Company's efforts to reduce complications through improved design. The development and completion of fibrous tissue ingrowth may work to reduce the occurrence of a foreign body reaction.

BACKGROUND:Corrosion has been documented in modular knee implants, but it has not been related to negative patient outcomes. We performed an observational retrieval investigation of 13 Stryker Triathlon TS modular knee implants, 3 of which were revised because of osteolysis and adverse local tissue reactions secondary to fretting corrosion at the modular junctions. METHODS:Modular surfaces were examined for the presence and severity of corrosion, and factors that may influence the development of corrosion were investigated. Scanning electron microscopy and energy-dispersive x-ray spectroscopy were performed to evaluate implants with severe corrosion, and tissue samples were sent for histopathological analysis. RESULTS:Mild to severe corrosion was present in association with 62% of modular tibial components and 75% of modular femoral components. Although tibial corrosion was less prevalent than femoral corrosion, it occurred earlier and with greater severity. Scanning electron microscopy and energy-dispersive x-ray spectroscopy demonstrated the appearances of fretting and corrosion of the modular junctions. Histopathological analysis of specimens from the 3 patients with adverse local tissue reactions demonstrated severe reactions to metal debris, including 1 reaction that was consistent with an aseptic lymphocyte-dominated vasculitis-associated lesion (ALVAL). CONCLUSIONS:To our knowledge, ALVAL and pseudotumors have not previously been reported secondary to corrosion of modular knee replacements. The threaded taper design and the release of cobalt-chromium ions and/or debris are implicated in the occurrence of the adverse local tissue reactions, osteolysis, and soft-tissue damage that we observed in our investigation. Clinicians should be aware of this possible complication associated with modular knee implants. CLINICAL RELEVANCE:This article should raise clinician awareness of adverse local tissue reactions secondary to corrosion, potentially resulting in earlier recognition of this complication.

INTRODUCTION:Retrievable inferior vena cava (IVC) filters have been increasingly used in patients with major trauma who have contraindications to anticoagulant prophylaxis as a primary prophylactic measure against venous thromboembolism (VTE). The benefits, risks and cost-effectiveness of such strategy are uncertain. METHODS AND ANALYSIS:Patients with major trauma, defined by an estimated Injury Severity Score >15, who have contraindications to anticoagulant VTE prophylaxis within 72 hours of hospitalisation to the study centre will be eligible for this randomised multicentre controlled trial. After obtaining consent from patients, or the persons responsible for the patients, study patients are randomly allocated to either control or IVC filter, within 72 hours of trauma admission, in a 1:1 ratio by permuted blocks stratified by study centre. The primary outcomes are (1) the composite endpoint of (A) pulmonary embolism (PE) as demonstrated by CT pulmonary angiography, high probability ventilation/perfusion scan, transoesophageal echocardiography (by showing clots within pulmonary arterial trunk), pulmonary angiography or postmortem examination during the same hospitalisation or 90-day after trauma whichever is earlier and (B) hospital mortality; and (2) the total cost of treatment including the costs of an IVC filter, total number of CT and ultrasound scans required, length of intensive care unit and hospital stay, procedures and drugs required to treat PE or complications related to the IVC filters. The study started in June 2015 and the final enrolment target is 240 patients. No interim analysis is planned; incidence of fatal PE is used as safety stopping rule for the trial. ETHICS AND DISSEMINATION:Ethics approval was obtained in all four participating centres in Australia. Results of the main trial and each of the secondary endpoints will be submitted for publication in a peer-reviewed journal. TRIAL REGISTRATION NUMBER:ACTRN12614000963628; Pre-results.