A UWB-Ego-Motion Particle Filter for Indoor Pose Estimation of a Ground Robot Using a Moving Horizon Hypothesis.

Ultra-wideband (UWB) has gained increasing interest for providing real-time positioning to robots in GPS-denied environments. For a robot to act on this information, it also requires its heading. This is, however, not provided by UWB. To overcome this, either multiple tags are used to create a local reference frame connected to the robot or a single tag is combined with ego-motion estimation from odometry or Inertial Measurement Unit (IMU) measurements. Both odometry and the IMU suffer from drift, and it is common to use a magnetometer to correct the drift on the heading; however, magnetometers tend to become unreliable in typical GPS-denied environments. To overcome this, a lightweight particle filter was designed to run in real time. The particle filter corrects the ego-motion heading and location drift using the UWB measurements over a moving horizon time frame. The algorithm was evaluated offline using data sets collected from a ground robot that contains line-of-sight (LOS) and non-line-of-sight conditions. An RMSE of 13 cm and 0.12 (rad) was achieved with four anchors in the LOS condition. It is also shown that it can be used to provide the robot with real-time position and heading information for the robot to act on it in LOS conditions, and it is shown to be robust in both experimental conditions.

Malpractice lawsuits in orthopedic trauma surgery: a meta-analysis of the literature.

Introduction: The objectives for this study were to identify whether diagnostic or procedural errors more commonly resulted in lawsuit, as well as to elucidate how specific variables affected mean indemnity. Methods: Systematic review of English-language articles in the PubMed and Google Scholar databases (through 2020) using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Meta-analysis was performed to estimate measures of proportions and differences in mean indemnity. Results: The estimated probability of lawsuits related to orthopedic trauma in overall studies was 23.3%. There were no significant rate differences between main causes of claims (diagnostic vs procedural errors) and areas of injury (upper vs lower). There was no significant difference of mean indemnity between the probabilities of trauma-related claims, diagnostic error, and procedural error. Conclusion: Non-trauma cases were more likely to result in lawsuit than trauma cases. Procedural errors accounted for most malpractice claims. The average indemnity increased according to the higher diagnostic errors, while the indemnity was lower with a relatively higher proportion of procedural errors. The most common cause of litigation varied between studies; however, among the most cited reasons were missed diagnosis/error in diagnosis, improper/substandard surgical performance, and, though not specifically studied in this analysis, errors of informed consent. Level of Evidence: Economic and Decision Analyses Level VI.

Outcomes and Complications With Treatment of Open Tibial Plafond Fractures With Circular External Fixator.

BACKGROUND: Open tibial plafond fractures (Orthopaedic Trauma Association and AO Foundation [OTA/AO] 43) are associated with severe complications, including deep infection (closed fractures, 20%; open fractures, 30%), amputation (3%-14%), and nonunion (up to 25%). Circular external fixators (CEFs) can minimize soft tissue injury. This study aimed to report the rate of union and occurrence of severe complications in patients with open tibial plafond fractures treated with CEFs. METHODS: A retrospective review of case series was conducted at 3 level I trauma centers. The study included patients older than 18 years with open tibial plafond fractures treated with CEFs. The reported outcomes included union rate, deep infection, operative complications, and limb alignment. The radiographic measurements of anatomic alignment were obtained. Fifty-two patients were included in the study. RESULTS: The primary union rate was 79%. No deep infection occurred in the majority (92%) of patients. No patient required amputation of the affected limb or free flap coverage. CONCLUSION: Definitive fixation of open tibial plafond fractures with CEFs avoided severe soft tissue complications but resulted in variation in final radiographic alignment. LEVEL OF EVIDENCE: Level IV, case series.

Electrical stimulation-based bone fracture treatment, if it works so well why do not more surgeons use it?

BACKGROUND: Electrical stimulation (EStim) has been proven to promote bone healing in experimental settings and has been used clinically for many years and yet it has not become a mainstream clinical treatment. METHODS: To better understand this discrepancy we reviewed 72 animal and 69 clinical studies published between 1978 and 2017, and separately asked 161 orthopedic surgeons worldwide about their awareness, experience, and acceptance of EStim for treating fracture patients. RESULTS: Of the 72 animal studies, 77% reported positive outcomes, and the most common model, bone, fracture type, and method of administering EStim were dog, tibia, large bone defects, and DC, respectively. Of the 69 clinical studies, 73% reported positive outcomes, and the most common bone treated, fracture type, and method of administration were tibia, delayed/non-unions, and PEMF, respectively. Of the 161 survey respondents, most (73%) were aware of the positive outcomes reported in the literature, yet only 32% used EStim in their patients. The most common fracture they treated was delayed/non-unions, and the greatest problems with EStim were high costs and inconsistent results. CONCLUSION: Despite their awareness of EStim's pro-fracture healing effects few orthopedic surgeons use it in their patients. Our review of the literature and survey indicate that this is due to confusion in the literature due to the great variation in methods reported, and the inconsistent results associated with this treatment approach. In spite of this surgeons seem to be open to using this treatment if advancements in the technology were able to provide an easy to use, cost-effective method to deliver EStim in their fracture patients.

Operative Versus Nonoperative Management Of Traumatic Arthrotomies from Civilian Gunshot Wounds.

Background: Although the rate of non-fatal gunshot wounds (GSW) has increased, few studies have compared the effectiveness of operative and nonoperative treatment with specific focus on infection. We compared the risk of septic arthritis in patients with traumatic arthrotomies caused by GSW treated operatively with irrigation and debridement versus nonoperatively with antibiotics and wound care. Methods: From 2009 to 2016, 46 patients at our institution sustained traumatic arthrotomies from low-velocity GSW with at least 90-day follow-up. Medical records were reviewed for demographic information, imaging, type and duration of antibiotics, details of operative and nonoperative interventions, and evidence of infection at follow-up visits. We measured the rate of septic arthritis using a 2-tailed t test. Results: The knee was the most commonly affected joint (34 patients; 73.9%). Eight patients (17.4%) were treated nonoperatively and 38 (82.6%) were treated operatively. In the nonoperative group, one patient (12.5%) developed a superficial wound infection that resolved with oral antibiotics. In the operative group, one patient (2.6%) developed a superficial wound infection requiring operative irrigation and debridement. There was no statistically significant difference in risk of infection between the two groups (P = 0.32). No patient developed septic arthritis. Conclusions: In select patients, nonoperative treatment with wound care and antibiotics may be sufficient for preventing infection after GSW-related traumatic arthrotomies. Findings of randomized studies and treatment algorithms are needed to further evaluate this relatively common injury.Level of Evidence: IV.

Tibial Plateau Fractures: A New Rank Ordering Method For Determining To What Degree Injury Severity Or Quality Of Reduction Correlate With Clinical Outcome.

BACKGROUND: Injury severity may be the most important factor in determining outcome after articular fractures, but there is a surprising paucity of clinical evidence to support this assertion. The purpose of this study was to utilize a new method for rank ordering a group of patient radiographs to assess the effect of injury severity and quality of reduction on patient outcomes after tibial plateau fractures. METHODS: Tibial plateau fractures in 64 patients were treated operatively or non-operatively based on physician preference from standard of care techniques. Fracture severity and reduction quality were stratified from radiographs by four expert clinicians using an iTunes-based rank ordering methodology. The images were distributed electronically, and the ranks were performed on local computers at three different institutions. Clinical outcomes were measured with the SF-12 health questionnaire and the Knee injury and Osteoarthritis Outcome Score (KOOS). RESULTS: There was excellent or very good agreement between raters for injury severity ranking (correlation 0.77-0.91) and quality of reduction (correlation 0.66-0.82). There was no correlation between the injury severity nor quality of reduction and general or joint-specific clinical outcomes. CONCLUSIONS: Expert orthopaedic traumatologists strongly agree on how to rank order tibial plateau fractures based both on injury severity and quality of reduction. The novel electronic interface utilized allows an ever-expanding series of cases to be ranked quickly, conveniently, and across multiple centers. This interface holds great promise for establishing prospective, continuously expanding rank orders of various fracture types, which may have great value for clinical research, education about fracture severity, and for prognosis and treatment decisions. In the present study, neither injury severity nor quality of reduction correlated with the clinical outcomes. Other patient- and injury-related factors may be more important in determining clinical outcome of tibial plateau fractures than the appearances of the radiographs at the time of injury or after reduction. Level of Evidence: level III evidence.

How Many Orthopaedic Surgeons Does It Take to Write a Manuscript? A Vignette-Based Discussion of Authorship in Orthopaedic Surgery.

The issue of appropriate authorship designation continues to be a topic of importance because authorship of scholarly work plays an important role in the academic community. It is a recognition of an individual's scholarly work and a factor in academic promotion. The Orthopaedic Trauma Association (OTA) sponsored a minisymposium in 2014 to encourage discussion of the issues that arise in authorship decisions. A residency program director/department chair, a journal editor, a clinical trials coordinator, and a promotions committee member provided viewpoints. In the pages that follow, vignettes are presented along with discussion points to encourage conversation on this topic. Authorship criteria are clearly defined. Authorship based simply on seniority or contribution of cases to clinical trials is inappropriate. Discussion of authorship criteria prior to the initiation of clinical research investigations is a standard that must be met. The International Committee of Medical Journal Editors (ICMJE) guidelines provide a framework for this discussion and should be reviewed by all authors prior to publication. Modifications to published authorship guidelines may be necessary to address some of the scenarios identified here that are not adequately addressed by the existing guidelines.

Risk Factors for Surgical Site Infections Following Anterior Cruciate Ligament Reconstruction.

OBJECTIVE To determine the effect of graft choice (allograft, bone-patellar tendon-bone autograft, or hamstring autograft) on deep tissue infections following anterior cruciate ligament (ACL) reconstructions. DESIGN Retrospective cohort study. SETTING AND POPULATION Patients from 6 US health plans who underwent ACL reconstruction from January 1, 2000, through December 31, 2008. METHODS We identified ACL reconstructions and potential postoperative infections using claims data. A hierarchical stratified sampling strategy was used to identify patients for medical record review to confirm ACL reconstructions and to determine allograft vs autograft tissue implanted, clinical characteristics, and infection status. We estimated infection rates overall and by graft type. We used logistic regression to assess the association between infections and patients' demographic characteristics, comorbidities, and choice of graft. RESULTS On review of 1,452 medical records, we found 55 deep wound infections. With correction for sampling weights, infection rates varied by graft type: 0.5% (95% CI, 0.3%-0.8%) with allografts, 0.6% (0.1%-1.5%) with bone-patellar tendon-bone autografts, and 2.5% (1.9%-3.1%) with hamstring autograft. After adjusting for potential confounders, we found an increased infection risk with hamstring autografts compared with allografts (odds ratio, 5.9; 95% CI, 2.8-12.8). However, there was no difference in infection risk among bone-patellar tendon-bone autografts vs allografts (odds ratio, 1.2; 95% CI, 0.3-4.8). CONCLUSIONS The overall risk for deep wound infections following ACL reconstruction is low but it does vary by graft type. Infection risk was highest in hamstring autograft recipients compared with allograft recipients and bone-patellar tendon-bone autograft recipients. Infect Control Hosp Epidemiol 2016;37:827-833.

Titanium mesh as a low-profile alternative for tension-band augmentation in patella fracture fixation: A biomechanical study.

OBJECTIVES: We performed a simple biomechanical study to compare the fixation strength of titanium mesh with traditional tension-band augmentation, which is a standard treatment for transverse patella fractures. We hypothesised that titanium mesh augmentation is not inferior in fixation strength to the standard treatment. METHODS: Twenty-four synthetic patellae were tested. Twelve were fixed with stainless steel wire and parallel cannulated screws. Twelve were fixed with parallel cannulated screws, augmented with anterior titanium mesh and four screws. A custom test fixture was developed to simulate a knee flexed to 90°. A uniaxial force was applied to the simulated extensor mechanism at this angle. A non-inferiority study design was used to evaluate ultimate force required for failure of each construct as a measure of fixation strength. Stiffness of the bone/implant construct, fracture gap immediately prior to failure, and modes of failure are also reported. RESULTS: The mean difference in force at failure was -23.0 N (95% CI: -123.6 to 77.6N) between mesh and wire constructs, well within the pre-defined non-inferiority margin of -260 N. Mean stiffness of the mesh and wire constructs were 19.42 N/mm (95% CI: 18.57-20.27 N/mm) and 19.49 N/mm (95% CI: 18.64-20.35 N/mm), respectively. Mean gap distance for the mesh constructs immediately prior to failure was 2.11 mm (95% CI: 1.35-2.88 mm) and 3.87 mm (95% CI: 2.60-5.13 mm) for wire constructs. CONCLUSIONS: Titanium mesh augmentation is not inferior to tension-band wire augmentation when comparing ultimate force required for failure in this simplified biomechanical model. Results also indicate that stiffness of the two constructs is similar but that the mesh maintains a smaller fracture gap prior to failure. The results of this study indicate that the use of titanium mesh plating augmentation as a low-profile alternative to tension-band wiring for fixation of transverse patella fractures warrants further investigation.

Pelvic crescent fractures: variations in injury mechanism and radiographic pattern.

Pelvic crescent fracture, also known as sacroiliac fracture-dislocation, is traditionally considered as a lateral compression injury and a vertically stable injury. Thirty consecutive cases were analyzed and it was found that 63% of cases were caused by lateral compression (LC), 27% by anteroposterior compression (APC), and 10% by vertical shear (VS). APC and VS injuries cause significant displacement of the anterior iliac fragment, but 21% of LC injury cases showed minimal displacement and were treated successfully with nonoperative treatment. Different injury mechanisms also produce different types of pelvic instability. More important, different injury mechanisms produce distinct radiographic fracture patterns regarding the obliquity of the fracture line and fracture surface. These differences in the fracture pattern will influence the decision of internal fixation options. Therefore, treatment of pelvic crescent fractures should be based on individual analysis of injury mechanism and radiographic fracture pattern.