Failure after operative repair is higher for ballistic femoral neck fractures than for closed, blunt-injury fractures: a multicenter retrospective cohort study.

Introduction: The purpose of this study was to describe the outcomes after operative repair of ballistic femoral neck fractures. To better highlight the devastating nature of these injuries, we compared a cohort of ballistic femoral neck fractures to a cohort of young, closed, blunt-injury femoral neck fractures treated with open reduction and internal fixation (ORIF). Methods: Retrospective chart review identified all patients presenting with ballistic femoral neck fractures treated at three academic trauma centers between January 2016 and December 2021, as well as patients aged ≤50 with closed, blunt-injury femoral neck fractures who received ORIF. The primary outcome was failure of ORIF, which includes the diagnosis of non-union, avascular necrosis, conversion to total hip arthroplasty, and conversion to Girdlestone procedure. Additional outcomes included deep infection, postoperative osteoarthritis, and ambulatory status at last follow-up. Results: Fourteen ballistic femoral neck fractures and 29 closed blunt injury fractures were identified. Of the ballistic fractures, 7 (50%) patients had a minimum of 1-year follow-up or met the failure criteria. Of the closed fractures, 16 (55%) patients had a minimum of 1-year follow-up or met the failure criteria. Median follow-up was 21 months. 58% of patients with ballistic fractures were active tobacco users. Five of 7 (71%) ballistic fractures failed, all of which involved non-union, whereas 8 of 16 (50%) closed fractures failed (p=0.340). No outcomes were significantly different between cohorts. Conclusion: Our results demonstrate that ballistic femoral neck fractures are associated with high rates of non-union. Large-scale multicenter studies are necessary to better determine optimal treatment techniques for these fractures. Level of evidence: Level III. Retrospective cohort study.

Psychological treatments for the management of pain after musculoskeletal injury: a systematic review and meta-analysis.

ABSTRACT: Musculoskeletal injury is a leading cause of pain and disability worldwide; 35% to 75% of people experience persistent pain for months and years after injury. Psychological treatments can reduce pain, functional impairment, and psychological distress but are not widely used after injury. This systematic review and meta-analysis (PROSPERO ID: CRD42021236807) aimed to synthesize the literature testing psychological treatments for pain after musculoskeletal injury. We searched EMBASE, MEDLINE, PubMed, PsycINFO, and CENTRAL from inception to May 2022. We extracted participant, treatment, and injury characteristics and primary (eg, pain intensity, functional impairment, depression, anxiety, and PTSD symptoms) and secondary (treatment feasibility and acceptability) outcomes. Twenty-four randomized controlled trials (N = 1966) were included. Immediately posttreatment, people who received psychological treatments (versus any control) reported lower pain intensity (standardized mean differences [SMD] = -0.25, 95% confidence interval [-0.49, -0.02]), functional impairment (SMD = -0.32 [-0.55, -0.09]), and symptoms of depression (SMD = -0.46 [-0.64, -0.29]), anxiety (SMD = -0.34 [-0.65, -0.04]), and PTSD (SMD = -0.43 [-0.70, -0.15]); at 6-month follow-up, only depression symptoms were significantly lower. Included trials varied widely in treatment and injury characteristics. The certainty of evidence was low or very low for most effects and heterogeneity moderate to substantial. Most studies had risk of bias domains judged to be high or unclear. Owing to very low certainty of results, we are unsure whether psychological therapies reduce pain and functional impairment after musculoskeletal injury; they may result in improved depression immediately posttreatment and at follow-up. More research is needed to identify treatments that result in enduring effects.

What Factors Are Associated With Delayed Wound Closure in Open Reduction and Internal Fixation of Adult Both-bone Forearm Fractures?

BACKGROUND: Delayed wound closure is often used after open reduction and internal fixation (ORIF) of both-bone forearm fractures to reduce the risk of skin necrosis and subsequent infection caused by excessive swelling. However, no studies we are aware of have evaluated factors associated with the use of delayed wound closure after ORIF. QUESTIONS/PURPOSES: (1) What proportion of patients undergo delayed wound closure after ORIF of adult both-bone forearm fractures? (2) What factors are associated with delayed wound closure? METHODS: The medical records of all patients who underwent ORIF with plate fixation for both-bone fractures by the adult orthopaedic trauma service at our institution were considered potentially eligible for analysis. Between January 2010 and April 2022, we treated 74 patients with ORIF for both-bone forearm fractures. Patients were excluded if they had fractures that were fixed more than 2 weeks from injury (six patients), if their fracture was treated with an intramedullary nail (one patient), or if the patient experienced compartment syndrome preoperatively (one patient). No patients with Gustilo-Anderson Type IIIB and C open fractures were included. Based on these criteria, 89% (66 of 74) of the patients were eligible. No further patients were excluded for loss of follow-up because the primary endpoint was the use of delayed wound closure, which was performed at the time of ORIF. However, one further patient was excluded for having bilateral forearm fractures to ensure that each patient had a single fracture for statistical analysis. Thus, 88% (65 of 74) of patients were included in the analysis. These patients were captured by an electronic medical record search of CPT code 25575. The mean ± SD age was 34 ± 15 years and mean BMI was 28 ± 7 kg/m 2 . The mean follow-up duration was 4 ± 5 months. The primary endpoint was the use of delayed wound closure, which was determined at the time of definitive fixation if tension-free closure could not be achieved. All surgeons used a volar Henry or modified Henry approach and a dorsal subcutaneous approach to the ulna for ORIF. Univariate logistic regression was used to identify which factors might be associated with delayed wound closure. A multivariable logistic regression analysis was then performed for male gender, open fractures, age, and BMI. RESULTS: Twenty percent (13 of 65) of patients underwent delayed wound closure, 18% (12 of 65) of which occurred in patients who had high-energy injuries and 14% (nine of 65) in patients who had open fractures. Being a man (adjusted odds ratio 9.9 [95% confidence interval 1 to 87]; p = 0.04) was independently associated with delayed wound closure, after adjusting for open fractures, age, and BMI. CONCLUSION: One of five patients had delayed wound closure after ORIF of both-bone forearm fractures. Being a man was independently associated with greater odds of delayed wound closure. Surgeons should counsel all patients with these fractures about the possibility of delayed wound closure, with particular attention to men with high-energy and open fractures. Future larger-scale studies are necessary to confirm which factors are associated with the use of delayed wound closure in ORIF of both-bone fractures and its effects on fracture healing. LEVEL OF EVIDENCE: Level III, therapeutic study.

Quantitative Dual-Energy Imaging of Bone Marrow Edema Using Multisource Cone-Beam CT with Model-Based Decomposition.

Purpose: We investigated the feasibility of dual-energy (DE) detection of bone marrow edema (BME) using a dedicated extremity cone-beam CT (CBCT) with a unique three-source x-ray unit. The sources can be operated at different energies to enable single-scan DE acquisitions. However, they are arranged parallel to the axis of rotation, resulting in incomplete sampling and precluding the application of DE projection-domain decompositions (PDD) for beam-hardening reduction. Therefore, we propose a novel combination of a model-based "one-step" DE two-material decomposition followed by a constrained image-domain change-of-basis to obtain virtual non-calcium (VNCa) images for BME detection. Methods: DE projections were obtained using an "alternating-kV" protocol by operating the peripheral two sources of the CBCT system at low-energy (60 kV, 0.105 mAs/frame) and the central source at high-energy (100 kV, 0.028 mAs/frame), for a total of 600 frames over 216° of gantry rotation. Projections were processed with detector lag, glare and fast Monte Carlo (MC)-based iterative scatter corrections. Model-based material decomposition (MBMD) was then implemented to obtain aluminum (Al) and polyethylene (PE) volume fraction images with minimal beam-hardening. Statistical ray weights in MBMD were modified to account for regions with highly oblique sampling by the peripheral sources. To generate the VNCa maps, image-domain decomposition (IDD) constrained by the volume conservation principle (VCP) was performed to convert the Al and PE MBMD images into volume fractions of water, fat and cortical bone. Accuracy of BME detection was evaluated using physical phantom data acquired on the multi-source extremity CBCT scanner. Results: The proposed framework estimated the volume of BME with ~10% error. The MC-based scatter corrections and the modified MBMD ray weights were essential to achieve such performance - the error without MC scatter corrections was >30%, whereas the uniformity of estimated VNCa images was 3x improved using the modified weights compared to the conventional weights. Conclusions: The proposed DE decomposition framework was able to overcome challenges of high scatter and incomplete sampling to achieve BME detection on a CBCT system with axially-distributed x-ray sources.

Model-based three-material decomposition in dual-energy CT using the volume conservation constraint.

Objective. We develop a model-based optimization algorithm for 'one-step' dual-energy (DE) CT decomposition of three materials directly from projection measurements.Approach.Since the three-material problem is inherently undetermined, we incorporate the volume conservation principle (VCP) as a pair of equality and nonnegativity constraints into the objective function of the recently reported model-based material decomposition (MBMD). An optimization algorithm (constrained MBMD, CMBMD) is derived that utilizes voxel-wise separability to partition the volume into a VCP-constrained region solved using interior-point iterations, and an unconstrained region (air surrounding the object, where VCP is violated) solved with conventional two-material MBMD. Constrained MBMD (CMBMD) is validated in simulations and experiments in application to bone composition measurements in the presence of metal hardware using DE cone-beam CT (CBCT). A kV-switching protocol with non-coinciding low- and high-energy (LE and HE) projections was assumed. CMBMD with decomposed base materials of cortical bone, fat, and metal (titanium, Ti) is compared to MBMD with (i) fat-bone and (ii) fat-Ti bases.Main results.Three-material CMBMD exhibits a substantial reduction in metal artifacts relative to the two-material MBMD implementations. The accuracies of cortical bone volume fraction estimates are markedly improved using CMBMD, with ∼5-10× lower normalized root mean squared error in simulations with anthropomorphic knee phantoms (depending on the complexity of the metal component) and ∼2-2.5× lower in an experimental test-bench study.Significance.In conclusion, we demonstrated one-step three-material decomposition of DE CT using volume conservation as an optimization constraint. The proposed method might be applicable to DE applications such as bone marrow edema imaging (fat-bone-water decomposition) or multi-contrast imaging, especially on CT/CBCT systems that do not provide coinciding LE and HE ray paths required for conventional projection-domain DE decomposition.

Visualization of Fluoroscopic Imaging in Orthopedic Surgery: Head-Mounted Display vs Conventional Monitor.

Purpose. See-through head-mounted displays (HMDs) can be used to view fluoroscopic imaging during orthopedic surgical procedures. The goals of this study were to determine whether HMDs reduce procedure time, number of fluoroscopic images required, or number of head turns by the surgeon compared with standard monitors. Methods. Sixteen orthopedic surgery residents each performed fluoroscopy-guided drilling of 8 holes for placement of tibial nail distal interlocking screws in an anatomical model, with 4 holes drilled while using HMD and 4 holes drilled while using a standard monitor. Procedure time, number of fluoroscopic images needed, and number of head turns by the resident during the procedure were compared between the 2 modalities. Statistical significance was set at P < .05. Results. Mean (SD) procedure time did not differ significantly between attempts using the standard monitor (55 [37] seconds) vs the HMD (56 [31] seconds) (P = .73). Neither did mean number of fluoroscopic images differ significantly between attempts using the standard monitor vs the HMD (9 [5] images for each) (P = .84). Residents turned their heads significantly more times when using the standard monitor (9 [5] times) vs the HMD (1 [2] times) (P < .001). Conclusions. Head-mounted displays lessened the need for residents to turn their heads away from the surgical field while drilling holes for tibial nail distal interlocking screws in an anatomical model; however, there was no difference in terms of procedure time or number of fluoroscopic images needed using the HMD compared with the standard monitor.

Development of a fluoroscopically guided robotic assistant for instrument placement in pelvic trauma surgery.

Purpose: A method for fluoroscopic guidance of a robotic assistant is presented for instrument placement in pelvic trauma surgery. The solution uses fluoroscopic images acquired in standard clinical workflow and helps avoid repeat fluoroscopy commonly performed during implant guidance. Approach: Images acquired from a mobile C-arm are used to perform 3D-2D registration of both the patient (via patient CT) and the robot (via CAD model of a surgical instrument attached to its end effector, e.g; a drill guide), guiding the robot to target trajectories defined in the patient CT. The proposed approach avoids C-arm gantry motion, instead manipulating the robot to acquire disparate views of the instrument. Phantom and cadaver studies were performed to determine operating parameters and assess the accuracy of the proposed approach in aligning a standard drill guide instrument. Results: The proposed approach achieved average drill guide tip placement accuracy of 1.57 ± 0.47 mm and angular alignment of 0.35 ± 0.32 deg in phantom studies. The errors remained within 2 mm and 1 deg in cadaver experiments, comparable to the margins of errors provided by surgical trackers (but operating without the need for external tracking). Conclusions: By operating at a fixed fluoroscopic perspective and eliminating the need for encoded C-arm gantry movement, the proposed approach simplifies and expedites the registration of image-guided robotic assistants and can be used with simple, non-calibrated, non-encoded, and non-isocentric C-arm systems to accurately guide a robotic device in a manner that is compatible with the surgical workflow.

Effect of Intrawound Vancomycin Powder in Operatively Treated High-risk Tibia Fractures: A Randomized Clinical Trial.

Importance: Despite the widespread use of systemic antibiotics to prevent infections in surgically treated patients with fracture, high rates of surgical site infection persist. Objective: To examine the effect of intrawound vancomycin powder in reducing deep surgical site infections. Design, Setting, and Participants: This open-label randomized clinical trial enrolled adult patients with an operatively treated tibial plateau or pilon fracture who met the criteria for a high risk of infection from January 1, 2015, through June 30, 2017, with 12 months of follow-up (final follow-up assessments completed in April 2018) at 36 US trauma centers. Interventions: A standard infection prevention protocol with (n = 481) or without (n = 499) 1000 mg of intrawound vancomycin powder. Main Outcomes and Measures: The primary outcome was a deep surgical site infection within 182 days of definitive fracture fixation. A post hoc comparison assessed the treatment effect on gram-positive and gram-negative-only infections. Other secondary outcomes included superficial surgical site infection, nonunion, and wound dehiscence. Results: The analysis included 980 patients (mean [SD] age, 45.7 [13.7] years; 617 [63.0%] male) with 91% of the expected person-time of follow-up for the primary outcome. Within 182 days, deep surgical site infection was observed in 29 of 481 patients in the treatment group and 46 of 499 patients in the control group. The time-to-event estimated probability of deep infection by 182 days was 6.4% in the treatment group and 9.8% in the control group (risk difference, -3.4%; 95% CI, -6.9% to 0.1%; P = .06). A post hoc analysis of the effect of treatment on gram-positive (risk difference, -3.7%; 95% CI, -6.7% to -0.8%; P = .02) and gram-negative-only (risk difference, 0.3%; 95% CI, -1.6% to 2.1%; P = .78) infections found that the effect of vancomycin powder was a result of its reduction in gram-positive infections. Conclusions and Relevance: Among patients with operatively treated tibial articular fractures at a high risk of infection, intrawound vancomycin powder at the time of definitive fracture fixation reduced the risk of a gram-positive deep surgical site infection, consistent with the activity of vancomycin. Trial Registration: ClinicalTrials.gov Identifier: NCT02227446.

Drill-mounted video guidance for orthopaedic trauma surgery.

Purpose: Percutaneous fracture fixation is a challenging procedure that requires accurate interpretation of fluoroscopic images to insert guidewires through narrow bone corridors. We present a guidance system with a video camera mounted onboard the surgical drill to achieve real-time augmentation of the drill trajectory in fluoroscopy and/or CT. Approach: The camera was mounted on the drill and calibrated with respect to the drill axis. Markers identifiable in both video and fluoroscopy are placed about the surgical field and co-registered by feature correspondences. If available, a preoperative CT can also be co-registered by 3D-2D image registration. Real-time guidance is achieved by virtual overlay of the registered drill axis on fluoroscopy or in CT. Performance was evaluated in terms of target registration error (TRE), conformance within clinically relevant pelvic bone corridors, and runtime. Results: Registration of the drill axis to fluoroscopy demonstrated median TRE of 0.9 mm and 2.0 deg when solved with two views (e.g., anteroposterior and lateral) and five markers visible in both video and fluoroscopy-more than sufficient to provide Kirschner wire (K-wire) conformance within common pelvic bone corridors. Registration accuracy was reduced when solved with a single fluoroscopic view ( TRE = 3.4 mm and 2.7 deg) but was also sufficient for K-wire conformance within pelvic bone corridors. Registration was robust with as few as four markers visible within the field of view. Runtime of the initial implementation allowed fluoroscopy overlay and/or 3D CT navigation with freehand manipulation of the drill up to 10 frames / s . Conclusions: A drill-mounted video guidance system was developed to assist with K-wire placement. Overall workflow is compatible with fluoroscopically guided orthopaedic trauma surgery and does not require markers to be placed in preoperative CT. The initial prototype demonstrates accuracy and runtime that could improve the accuracy of K-wire placement, motivating future work for translation to clinical studies.

Head-Mounted Display Use in Surgery: A Systematic Review.

Purpose. We analyzed the literature to determine (1) the surgically relevant applications for which head-mounted display (HMD) use is reported; (2) the types of HMD most commonly reported; and (3) the surgical specialties in which HMD use is reported. Methods. The PubMed, Embase, Cochrane Library, and Web of Science databases were searched through August 27, 2017, for publications describing HMD use during surgically relevant applications. We identified 120 relevant English-language, non-opinion publications for inclusion. HMD types were categorized as "heads-up" (nontransparent HMD display and direct visualization of the real environment), "see-through" (visualization of the HMD display overlaid on the real environment), or "non-see-through" (visualization of only the nontransparent HMD display). Results. HMDs were used for image guidance and augmented reality (70 publications), data display (63 publications), communication (34 publications), and education/training (18 publications). See-through HMDs were described in 55 publications, heads-up HMDs in 41 publications, and non-see-through HMDs in 27 publications. Google Glass, a see-through HMD, was the most frequently used model, reported in 32 publications. The specialties with the highest frequency of published HMD use were urology (20 publications), neurosurgery (17 publications), and unspecified surgical specialty (20 publications). Conclusion. Image guidance and augmented reality were the most commonly reported applications for which HMDs were used. See-through HMDs were the most commonly reported type used in surgically relevant applications. Urology and neurosurgery were the specialties with greatest published HMD use.

Minimally Invasive Fixation for Spinopelvic Dissociation: Percutaneous Triangular Osteosynthesis with S2 Alar-Iliac and Iliosacral Screws: A Case Report.

CASE: Traumatic U- and H-type sacral fractures are often unstable, causing spinopelvic dissociation. We describe a minimally invasive approach that allows percutaneous spinopelvic fixation of unstable H-type sacral fractures using a triangular osteosynthesis construct with S2 alar-iliac screws. We present the case of a patient with traumatic lumbopelvic dissociation who underwent percutaneous S2 alar-iliac and iliosacral screw fixation. CONCLUSIONS: Combined percutaneous S2 alar-iliac and iliosacral screw fixation is a safe option for spinopelvic fixation and avoids the soft-tissue compromise of open approaches. The triangular osteosynthesis construct provides adequate pelvic anchor points to allow immediate weight-bearing.

Reducing routine laboratory tests in patients with isolated extremity fractures: a prospective safety and feasibility study in 246 patients.

BACKGROUND: Daily routine laboratory testing is unnecessary in most admitted patients. The opportunity to reduce daily laboratory testing in orthopaedic trauma patients has not been previously investigated. METHODS: A prospective observational study was performed based on a new laboratory testing reduction protocol for 12 months at two tertiary care trauma centers. Admitted patients with surgically treated isolated upper or lower extremity fractures were included (n = 246). The testing protocol consisted of a complete blood count (CBC) and basic metabolic panel (BMP) on postoperative day 2. Thereafter, tests were obtained at individual providers' discretion. Patients were followed for 30 days postoperatively. The primary outcome was number of laboratory tests reduced. Secondary outcomes included provider protocol compliance, and adverse patient outcomes. Chi-squared tests were used to compare differences in categorical variables among the cohorts. Analysis of variance tests were used for continuous variables. The relative reductions in testing utilization were calculated using our division's standard-of-care before program implementation (1 CBC and 1 BMP per patient per inpatient day). Significance was defined as P < 0.05. RESULTS: Of the 246 patients, there were 45 protocol fall outs due to provider deviation (n = 24) or medically justified necessity for additional testing (n = 21). Across all groups, a total of 778 CBC or BMP tests were avoided, amounting to a 69% reduction in testing compared to the pre-implementation baseline. Ninety-five percent of protocol group patients were safely discharged either without laboratory testing or with one set of tests obtained on postoperative day 2. There were no 30-day readmissions or reported complications associated with the new laboratory testing protocol. CONCLUSIONS: In patients with surgically treated fractures about the elbow and knee, obtaining a single set of laboratory tests on postoperative day 2 is safe and efficacious in terms of reducing inappropriate resource utilization. TRIAL REGISTRATION: retrospectively registered.

Enhancement of Anatomical Education Using Augmented Reality: An Empirical Study of Body Painting.

Students in undergraduate premedical anatomy courses may experience suboptimal and superficial learning experiences due to large class sizes, passive lecture styles, and difficult-to-master concepts. This study introduces an innovative, hands-on activity for human musculoskeletal system education with the aim of improving students' level of engagement and knowledge retention. In this study, a collaborative learning intervention using the REFLECT (augmented reality for learning clinical anatomy) system is presented. The system uses the augmented reality magic mirror paradigm to superimpose anatomical visualizations over the user's body in a large display, creating the impression that she sees the relevant anatomic illustrations inside her own body. The efficacy of this proposed system was evaluated in a large-scale controlled study, using a team-based muscle painting activity among undergraduate premedical students (n = 288) at the Johns Hopkins University. The baseline knowledge and post-intervention knowledge of the students were measured before and after the painting activity according to their assigned groups in the study. The results from knowledge tests and additional collected data demonstrate that the proposed interactive system enhanced learning of the musculoskeletal system with improved knowledge retention (F(10,133)  = 3.14, P < 0.001), increased time on task (F(1,275)  = 5.70, P < 0.01), and a high level of engagement (F(9,273)  = 8.28, P < 0.0001). The proposed REFLECT system will be of benefit as a complementary anatomy learning tool for students.

Reliability of distal tibio-fibular syndesmotic instability measurements using weightbearing and non-weightbearing cone-beam CT.

BACKGROUND: To investigate the reliability and reproducibility of syndesmosis measurements on weightbearing (WB) cone-beam computed tomography (CBCT) images and compare them with measurements obtained using non-weightbearing (NWB) images. METHODS: In this IRB-approved, retrospective study of 5 men and 9 women with prior ankle injuries, simultaneous WB and NWB CBCT scans were taken. A set of 21 syndesmosis measurements using WB and NWB images were performed by 3 independent observers. Pearson/Spearman correlation and intra-class correlation (ICC) were used to assess intra- and inter-observer reliability, respectively. RESULTS: We observed substantial to perfect intra-observer reliability (ICC=0.72-0.99) in 20 measurements. Moderate to perfect agreement (ICC=0.45-0.97) between observers was noted in 19 measurements. CONCLUSION: Measurements evaluating the distance between tibia and fibula in the axial plane 10mm above the plafond had high intra- and inter-observer reliability. Mean posterior tibio-fibular distance, diastasis, and angular measurement were significantly different between WB and NWB images.

Cone-beam CT measurements of distal tibio-fibular syndesmosis in asymptomatic uninjured ankles: does weight-bearing matter?

OBJECTIVE: To evaluate the influence of weight-bearing (WB) load in standard axial ankle syndesmotic measurements using cone beam CT (CBCT) examination of asymptomatic uninjured ankles. MATERIALS AND METHODS: In this IRB approved, prospective study, patients with previous unilateral ankle fractures were recruited. We simultaneously scanned the injured ankles and asymptomatic contralateral ankles of 27 patients in both WB and NWB modes. For this study, only asymptomatic contralateral ankles with normal plain radiographs were included. Twelve standardized syndesmosis measurements at two axial planes (10 mm above the tibial plafond and 5 mm below the talar dome) were obtained by two expert readers using a custom CBCT viewer with the capability for geometric measurements between user-identified anatomical landmarks. Inter-reader reliability between two readers was obtained using the intra-class correlation coefficient (ICC). We compared the WB and NWB measurements using paired t test. RESULTS: Significant agreement was observed between two readers for both WB and NWB measurements (p <0.05). ICC values for WB and NWB measurements had a range of 50-95 and 31-71 respectively. Mean values of the medial clear space on WB images (1.75, 95% confidence interval [95% CI]: 1.6, 1.9) were significantly lower than on NWB images (2.05, 95% CI: 1.8, 2.2) measurements (p <0.001). There was no significant difference between the remaining WB and NWB measurements. CONCLUSION: Measurements obtained from WB images are reliable. Except for the medial clear space, no significant difference in syndesmotic measurements were observed during the WB mode of CBCT acquisition, implying that the tibio-fibular relationship remains unchanged when the physiological axial weight-bearing load is applied.

Venous Thromboembolism in Upper Extremity Fractures.

BACKGROUND: Venous thromboembolism (VTE) has been studied in lower extremity fractures but little is known of its relation with upper extremity (UE) fractures. As an often overlooked but serious complication, VTE may compromise patient outcomes. METHODS: Using data on inpatients (aged ≥ 18 years) at a level-I trauma center and patients in the National Surgical Quality Improvement Program database who sustained UE fractures (clavicle, humerus, or radius/ulna) and VTE in the same hospitalization between 2007 and 2014, the authors analyzed data on demographic characteristics, fracture type, VTE location (pulmonary embolism, lower extremity, or UE), VTE onset, polytrauma, operative or nonoperative management, comorbidities, and mortality. RESULTS: Of 1984 inpatients with UE fractures at 1 instution, 9 experienced VTE on admission, and 17 (15 received thromboprophylaxis) experienced VTE during hospitalization, for an overall VTE rate of 1.3%. VTE occurred most often in patients with fractures of the proximal humerus (3.0%) followed by the clavicle (2.0%), midshaft humerus (1.9%), distal radius/ulna (0.95%), and distal humerus/elbow (0.36%) (p = 0.0035). There were no significant trends in the incidence of PE (p = 0.33) over the study period, but there was a sharp rise since 2011. In the national database, 42 of 11570 (0.36%) patients with UE fracture had VTE, with incidence by fracture location ranging from 0.14% (radius/ulna) to 0.98% (proximal humerus) (p = 0.00001). Predictors were chronic steroid use (odds ratio [OR] = 6.22, p = .030), inpatient status (OR = 4.09, p = .002), and totally disabled functional status (OR = 3.31, p = .021). CONCLUSIONS: VTE incidence was highest following proximal humerus or clavicle fractures and are rarely associated with radius/ulna fractures. There may have been a rise in the incidence of PE since 2007, warranting further investigation.

Mobile C-Arm with a CMOS detector: Technical assessment of fluoroscopy and Cone-Beam CT imaging performance.

PURPOSE: Indirect-detection CMOS flat-panel detectors (FPDs) offer fine pixel pitch, fast readout, and low electronic noise in comparison to current a-Si:H FPDs. This work investigates the extent to which these potential advantages affect imaging performance in mobile C-arm fluoroscopy and cone-beam CT (CBCT). METHODS: FPDs based on CMOS (Xineos 3030HS, 0.151 mm pixel pitch) or a-Si:H (PaxScan 3030X, 0.194 mm pixel pitch) sensors were outfitted on equivalent mobile C-arms for fluoroscopy and CBCT. Technical assessment of 2D and 3D imaging performance included measurement of electronic noise, gain, lag, modulation transfer function (MTF), noise-power spectrum (NPS), detective quantum efficiency (DQE), and noise-equivalent quanta (NEQ) in fluoroscopy (with entrance air kerma ranging 5-800 nGy per frame) and cone-beam CT (with weighted CT dose index, CTDIw , ranging 0.08-1 mGy). Image quality was evaluated by clinicians in vascular, orthopaedic, and neurological surgery in realistic interventional scenarios with cadaver subjects emulating a variety of 2D and 3D imaging tasks. RESULTS: The CMOS FPD exhibited ~2-3× lower electronic noise and ~7× lower image lag than the a-Si:H FPD. The 2D (projection) DQE was superior for CMOS at ≤50 nGy per frame, especially at high spatial frequencies (~2% improvement at 0.5 mm-1 and ≥50% improvement at 2.3 mm-1 ) and was somewhat inferior at moderate-high doses (up to 18% lower DQE for CMOS at 0.5 mm-1 ). For smooth CBCT reconstructions (low-frequency imaging tasks), CMOS exhibited ~10%-20% higher NEQ (at 0.1-0.5 mm-1 ) at the lowest dose levels (CTDIw ≤0.1 mGy), while the a-Si:H system yielded slightly (~5%) improved NEQ (at 0.1-0.5 lp/mm) at higher dose levels (CTDIw ≥0.6 mGy). For sharp CBCT reconstructions (high-frequency imaging tasks), NEQ was ~32% higher above 1 mm-1 for the CMOS system at mid-high-dose levels and ≥75% higher at the lowest dose levels (CTDIw ≤0.1 mGy). Observer assessment of 2D and 3D cadaver images corroborated the objective metrics with respect to a variety of pertinent interventional imaging tasks. CONCLUSION: Measurements of image noise, spatial resolution, DQE, and NEQ indicate improved low-dose performance for the CMOS-based system, particularly at lower doses and higher spatial frequencies. Assessment in realistic imaging scenarios confirmed improved visibility of fine details in low-dose fluoroscopy and CBCT. The results quantitate the extent to which CMOS detectors improve mobile C-arm imaging performance, especially in 2D and 3D imaging scenarios involving high-resolution tasks and low-dose conditions.

Automatic intraoperative stitching of nonoverlapping cone-beam CT acquisitions.

PURPOSE: Cone-beam computed tomography (CBCT) is one of the primary imaging modalities in radiation therapy, dentistry, and orthopedic interventions. While CBCT provides crucial intraoperative information, it is bounded by a limited imaging volume, resulting in reduced effectiveness. This paper introduces an approach allowing real-time intraoperative stitching of overlapping and nonoverlapping CBCT volumes to enable 3D measurements on large anatomical structures. METHODS: A CBCT-capable mobile C-arm is augmented with a red-green-blue-depth (RGBD) camera. An offline cocalibration of the two imaging modalities results in coregistered video, infrared, and x-ray views of the surgical scene. Then, automatic stitching of multiple small, nonoverlapping CBCT volumes is possible by recovering the relative motion of the C-arm with respect to the patient based on the camera observations. We propose three methods to recover the relative pose: RGB-based tracking of visual markers that are placed near the surgical site, RGBD-based simultaneous localization and mapping (SLAM) of the surgical scene which incorporates both color and depth information for pose estimation, and surface tracking of the patient using only depth data provided by the RGBD sensor. RESULTS: On an animal cadaver, we show stitching errors as low as 0.33, 0.91, and 1.72 mm when the visual marker, RGBD SLAM, and surface data are used for tracking, respectively. CONCLUSIONS: The proposed method overcomes one of the major limitations of CBCT C-arm systems by integrating vision-based tracking and expanding the imaging volume without any intraoperative use of calibration grids or external tracking systems. We believe this solution to be most appropriate for 3D intraoperative verification of several orthopedic procedures.

Catastrophic Failure of a Carbon-Fiber-Reinforced Polyetheretherketone Tibial Intramedullary Nail: A Case Report.

CASE: We present a case of a rare low-energy catastrophic failure of a carbon-fiber-reinforced polyetheretherketone tibial intramedullary nail at 10 weeks after placement in a 36-year-old man. We describe our experience with extraction of the device. CONCLUSION: Carbon-fiber composite implants are approved for clinical use in orthopaedic trauma applications. The rare failure of carbon-fiber implants presents unique challenges because typical extraction techniques cannot be used. With the patient described herein, a terminally threaded guidewire was used to cannulate and extract the distal segment of the nail.

Use of the S3 Corridor for Iliosacral Fixation in a Dysmorphic Sacrum: A Case Report.

CASE: The S1 and S2 corridors are the typical osseous pathways for iliosacral screw fixation of posterior pelvic ring fractures. In dysmorphic sacra, the S1 screw trajectory is often different from that in normal sacra. We present a case of iliosacral screw placement in the third sacral segment for fixation of a complex lateral compression type-3 pelvic fracture in a patient with a dysmorphic sacrum. CONCLUSION: In patients with dysmorphic sacra and unstable posterior pelvic ring fractures or dislocations, the S3 corridor may be a feasible osseous fixation pathway that can be used in a manner equivalent to the S2 corridor in a normal sacrum.