3D printing techniques have attracted a lot of curiosity in various surgical specialties and the applications of the 3D technology have been explored in many ways including fracture models for education, customized jigs, custom implants, prosthetics etc. Often the 3D printing technology remains underutilized in potential areas due to costs and technological expertise being the perceived barriers. We have applied 3D printing technology for acetabular fracture surgeries with in-house, surgeon made models of mirrored contralateral unaffected acetabulum based on the patients’ trauma CT Scans in 9 patients. The CT Scans are processed to the print with all free-ware modeling software and relatively inexpensive printer by the surgeon and the resulting model is used as a ‘reduced fracture template’ for pre-contouring the standard pelvic reconstruction plates. This allows use of the standard surgical implants, saves time on intra-operative plate contouring, and also aids in reduction to an extent. We share through this presentation the workflow of the freeware softwares to use in order to use this surgical planning and implant preparation that may remove the perceived barriers of cost and technology from surgeons that wish to explore using 3D printing technology for acetabular fracture management and may extend applications to other regions

Nowadays, foot switches are used in almost every operating theatre to support the interaction with medical devices. Foot switches are especially used to release risk-sensitive functions of e.g. the drilling device, the high-frequency device or the X-ray C-arm. In general, the use of foot switches facilitates the work, since they enable the surgeon to use both hands exclusively for the manipulation within the operation procedures. Due to the increasing number of (complex) devices controlled by foot switches, the surgeons face a variety of challenges regarding usability and safety of these human-machine-interfaces. In the future, the approach of integrated medical devices in the OR on the basis of the open communication standard IEEE 11073 gives the opportunity to provide a central surgical cockpit with a universal foot switch for the surgeon, enabling the interaction with various devices different manufacturers. In the framework of the ongoing OR.NET initiative founded on the basis of the OR.NET research project (2012–2016) a novel concept for a universal foot switch (within the framework of a surgical workstation) has been developed in order to optimise the intraoperative workflow for the OR-personnel. Here, we developed three wireless functional models of a universal foot switch together with a standardised modular interface for visual feedback via a central surgical cockpit display. Within the development of our latest foot switch, the requirements have been inter alia to provide adequate functionalities to cover the needs for the interventions in the medical disciplines orthopaedic surgery, neurosurgery and ENT. The evaluation has been conducted within an interaction-centered usability analysis with surgeons from orthopaedics, neurosurgery and ENT. By using the Thinking Aloud technique in a Wizard-of-Oz experiment the usability criteria effectiveness, learnability and user satisfaction have been analysed. Regarding learnability 83.25% of the subjects stated that the usage of the universal foot switch is easy to learn. An average of 77,2% of users rated the usability of the universal foot switch between good and excellent on the SUS scale. The intuitiveness of the graphical user interface has been approved with 91.75% and the controllability with 83.25%. Finally, 86% of the subjects stated a high user satisfaction

Introduction. Recent technological advancements have led to the introduction of robotic-assisted total knee arthroplasty to improve the accuracy and precision of bony resections and implant position. However, the in vivo accuracy is not widely reported. The primary objective of this study is to determine the accuracy and precision of a cut block positioning robotic arm. Method. Seventy-seven patients underwent total knee arthroplasty with various workflows and alignment targets by three arthroplasty-trained surgeons with previous experience using the ROSA® Knee System. Accuracy and precision were determined by measuring the difference between various workflow time points, including the final pre-operative plan, validated resection angle, and post-operative radiographs. The mean difference between the measurements determined accuracy, and the standard deviation represented precision. Results. The accuracy and precision for all angles comparing the final planned resection and validated resection angles was 0.90° ± 0.76°. The proportion within 3° ranged from 97.9% to 100%. The accuracy and precision for all angles comparing the final intra- operative plan and post-operative radiographs was 1.95 ± 1.48°. The proportion of patients within 3° was 93.2%, 95.3%, 96.6%, and 71.4% for the distal femur, proximal tibia, femoral flexion, and tibial slope angles when the final intra-operative plan was compared to post-operative radiographs. No patients had a postoperative complication requiring revision at the final follow-up. Conclusions. This study demonstrates that the ROSA Knee System has accurate and precise coronal plane resections with few outliers. However, the tibial slope demonstrated decreased accuracy and precision were measured on post-operative short-leg lateral radiographs with this platform

Virtual encounters have experienced an exponential rise amid the current COVID-19 crisis. This abrupt change, seen in response to unprecedented medical and environmental challenges, has been forced upon the orthopaedic community. However, such changes to adopting virtual care and technology were already in the evolution forecast, albeit in an unpredictable timetable impeded by regulatory and financial barriers. This adoption is not meant to replace, but rather augment established, traditional models of care while ensuring patient/provider safety, especially during the pandemic. While our department, like those of other institutions, has performed virtual care for several years, it represented a small fraction of daily care. The pandemic required an accelerated and comprehensive approach to the new reality. Contemporary literature has already shown equivalent safety and patient satisfaction, as well as superior efficiency and reduced expenses with musculoskeletal virtual care (MSKVC) versus traditional models. Nevertheless, current literature detailing operational models of MSKVC is scarce. The current review describes our pre-pandemic MSKVC model and the shift to a MSKVC pandemic workflow that enumerates the conceptual workflow organization (patient triage, from timely care provision based on symptom acuity/severity to a continuum that includes future follow-up). Furthermore, specific setup requirements (both resource/personnel requirements such as hardware, software, and network connectivity requirements, and patient/provider characteristics respectively), and professional expectations are outlined. MSKVC has already become a pivotal element of musculoskeletal care, due to COVID-19, and these changes are confidently here to stay. Readiness to adapt and evolve will be required of individual musculoskeletal clinical teams as well as organizations, as established paradigms evolve. Cite this article: Bone Joint Open 2020;1-6:272–280

Aims. COVID-19 has changed the practice of orthopaedics across the globe. The medical workforce has dealt with this outbreak with varying strategies and adaptations, which are relevant to its field and to the region. As one of the ‘hotspots’ in the UK , the surgical branch of trauma and orthopaedics need strategies to adapt to the ever-changing landscape of COVID-19. Methods. Adapting to the crisis locally involved five operational elements: 1) triaging and workflow of orthopaedic patients; 2) operation theatre feasibility and functioning; 3) conservation of human resources and management of workforce in the department; 4) speciality training and progression; and 5) developing an exit strategy to resume elective work. Two hospitals under our trust were redesignated based on the treatment of COVID-19 patients. Registrar/consultant led telehealth reviews were carried out for early postoperative patients. Workflows for the management of outpatient care and inpatient care were created. We looked into the development of a dedicated operating space to perform the emergency orthopaedic surgeries without symptoms of COVID-19. Between March 23 and April 23, 2020, we have surgically treated 133 patients across both our hospitals in our trust. This mainly included hip fractures and fractures/infection affecting the hand. Conclusion. The COVID-19 pandemic is not the first disease outbreak affecting the UK, nor will it be the last. The current crisis has necessitated rapid development of new hospital guidelines and early adaptive strategies in our services. Protocols and directives need to be formalized keeping in mind that COVID-19 will have a long and protracted course until a definitive cure is discovered

The Coronal Plane Alignment of the Knee (CPAK) is a recent method for classifying knees using the hip-knee-ankle angle and joint line obliquity to assist surgeons in selection of an optimal alignment philosophy in total knee arthroplasty (TKA)1. It is unclear, however, how CPAK classification impacts pre-operative joint balance. Our objective was to characterise joint balance differences between CPAK categories. A retrospective review of TKA's using the OMNIBotics platform and BalanceBot (Corin, UK) using a tibia first workflow was performed. Lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) were landmarked intra-operatively and corrected for wear. Joint gaps were measured under a load of 70–90N after the tibial resection. Resection thicknesses were validated to recreate the pre-tibial resection joint balance. Knees were subdivided into 9 categories as described by MacDessi et al.1 Differences in balance at 10°, 40° and 90° were determined using a one-way 2-tailed ANOVA test with a critical p-value of 0.05. 1124 knees satisfied inclusion criteria. The highest proportion of knees (60.7%) are CPAK I with a varus aHKA and Distal Apex JLO, 79.8% report a Distal Apex JLO and 69.3% report a varus aHKA. Greater medial gaps are observed in varus (I, IV, VII) compared to neutral (II, V, VIII) and valgus knees (III, VI, IX) (p<0.05 in all cases) as well as in the Distal Apex (I, II, III) compared to Neutral groups (IV, V, VI) (p<0.05 in all cases). Comparisons could not be made with the Proximal Apex groups due to low frequency (≤2.5%). Significant differences in joint balance were observed between and within CPAK groups. Although both hip-knee-ankle angle and joint line orientation are associated with joint balance, boney anatomy alone is not sufficient to fully characterize the knee

Introduction. Clinical decision support tools are software that match the input characteristics of an individual patient to an established knowledge base to create patient-specific assessments that support and better inform individualized healthcare decisions. Clinical decision support tools can facilitate better evidence-based care and offer the potential for improved treatment quality and selection, shared decision making, while also standardizing patient expectations. Methods. Predict+ is a novel, clinical decision support tool that leverages clinical data from the Exactech Equinoxe shoulder clinical outcomes database, which is composed of >11,000 shoulder arthroplasty patients using one specific implant type from more than 30 different clinical sites using standardized forms. Predict+ utilizes multiple coordinated and locked supervised machine learning algorithms to make patient-specific predictions of 7 outcome measures at multiple postoperative timepoints (from 3 months to 7 years after surgery) using as few as 19 preoperative inputs. Predict+ algorithms predictive accuracy for the 7 clinical outcome measures for each of aTSA and rTSA were quantified using the mean absolute error and the area under the receiver operating curve (AUROC). Results. Predict+ was released in November 2020 and is currently in limited launch in the US and select international markets. Predict+ utilizes an interactive graphical user interface to facilitate efficient entry of the preoperative inputs to generate personalized predictions of 7 clinical outcome measures achieved with aTSA and rTSA. Predict+ outputs a simple, patient-friendly graphical overview of preoperative status and a personalized 2-year outcome summary of aTSA and rTSA predictions for all 7 outcome measures to aid in the preoperative patient consultation process. Additionally, Predict+ outputs a detailed line-graph view of a patient's preoperative status and their personalized aTSA, rTSA, and aTSA vs. rTSA predicted outcomes for the 7 outcome measures at 6 postoperative timepoints. For each line-graph, the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) patient-satisfaction improvement thresholds are displayed to aid the surgeon in assessing improvement potential for aTSA and rTSA and also relative to an average age and gender matched patient. The initial clinical experience of Predict+ has been positive. Input of the preoperative patient data is efficient and generally completed in <5 minutes. However, continued workflow improvements are necessary to limit the occurrence of responder fatigue. The graphical user interface is intuitive and facilitated a rapid assessment of expected patient outcomes. We have not found the use of this tool to be disruptive of our clinic's workflow. Ultimately, this tool has positively shifted the preoperative consultation towards discussion of clinical outcomes data, and that has been helpful to guide a patient's understanding of what can be realistically achieved with shoulder arthroplasty. Discussion and Conclusions. Predict+ aims to improve a surgeon's ability to preoperatively counsel patients electing to undergo shoulder arthroplasty. We are hopeful this innovative tool will help align surgeon and patient expectations and ultimately improve patient satisfaction with this elective procedure. Future research is required, but our initial experience demonstrates the positive potential of this predictive tool

Aim. Staphylococcus aureus (SA) can cause various infections and is associated with high morbidity and mortality rates of up to 40%. Antibiotic treatment often fails to eradicate SA infections even if the causative strain has been tested susceptible in vitro. The mechanisms leading to this persistence is still largely unknown. In our work, we to reveal SA interactions with host cells that allow SA to persist at the site of infection. Method. We established a sampling workflow to receive tissue samples from patients requiring surgical debridement due to SA bone-and joint or soft-tissue infections. We developed a multiplex immunofluorescent staining protocol which allowed us to stain for SA, leukocytes, neutrophils, macrophages, B-cells, T-cells, DAPI and cytoplasmatic marker on the same sample slide. Further, distance of SA to cell nuclei was measured. Interaction of immune cells and SA on a single cell level was investigated with high-resolution 3D microscopy. We then validated our findings applying fluorescence-activated cell sorting (FACS) on digested patient samples. Finally, we aimed to reproduce our ex vivo patient results in an in vitro co-culture model of primary macrophages and clinical SA strains, where we used live cell microscopy and high-resolution microscopy to visualize SA-immune cell interactions and a gentamicin protection assay to assess viability of SA. Results. Here, we revealed that CD68+ macrophages were the immune cells closest to SA with a mean distance of 56μm (SD=36.4μm). Counting the amount of SA, we found in total >7000 single SA in nine patients. Two-thirds of SA were located intracellularly. Two-thirds of the affected immune cells with intracellular SA were macrophages. The distribution of intra- to extracellular SA was independent of ongoing antibiotic therapy and underlying infection type. FACS confirmed these findings. In our co-culture model, intracellular SA remained alive for the whole observation period of eight hours and resided in RAB5+ early phagosomes. Conclusions. Our study suggests an essential role of intracellular survival in macrophages in SA infections. These findings may have major implication for future treatment strategies

Single level discectomy (SLD) is one of the most commonly performed spinal surgery procedures. Two key drivers of their cost-of-care are duration of surgery (DOS) and postoperative length of stay (LOS). Therefore, the ability to preoperatively predict SLD DOS and LOS has substantial implications for both hospital and healthcare system finances, scheduling and resource allocation. As such, the goal of this study was to predict DOS and LOS for SLD using machine learning models (MLMs) constructed on preoperative factors using a large North American database. The American College of Surgeons (ACS) National Surgical and Quality Improvement (NSQIP) database was queried for SLD procedures from 2014-2019. The dataset was split in a 60/20/20 ratio of training/validation/testing based on year. Various MLMs (traditional regression models, tree-based models, and multilayer perceptron neural networks) were used and evaluated according to 1) mean squared error (MSE), 2) buffer accuracy (the number of times the predicted target was within a predesignated buffer), and 3) classification accuracy (the number of times the correct class was predicted by the models). To ensure real world applicability, the results of the models were compared to a mean regressor model. A total of 11,525 patients were included in this study. During validation, the neural network model (NNM) had the best MSEs for DOS (0.99) and LOS (0.67). During testing, the NNM had the best MSEs for DOS (0.89) and LOS (0.65). The NNM yielded the best 30-minute buffer accuracy for DOS (70.9%) and ≤120 min, >120 min classification accuracy (86.8%). The NNM had the best 1-day buffer accuracy for LOS (84.5%) and ≤2 days, >2 days classification accuracy (94.6%). All models were more accurate than the mean regressors for both DOS and LOS predictions. We successfully demonstrated that MLMs can be used to accurately predict the DOS and LOS of SLD based on preoperative factors. This big-data application has significant practical implications with respect to surgical scheduling and inpatient bedflow, as well as major implications for both private and publicly funded healthcare systems. Incorporating this artificial intelligence technique in real-time hospital operations would be enhanced by including institution-specific operational factors such as surgical team and operating room workflow

Introduction. The ability to create patient-specific implants (PSI) at the point-of-care has become a desire for clinicians wanting to provide affordable and customized treatment. While some hospitals have already adopted extrusion-based 3D printing (fused filament fabrication; FFF) for creating non-implantable instruments, recent innovations have allowed for the printing of high-temperature implantable polymers including polyetheretherketone (PEEK). With interest in FFF PEEK implants growing, it is important to identify methods for printing favorable implant characteristics such as porosity for osseointegration. In this study, we assess the effect of porous geometry on the cell response and mechanical properties for FFF-printed porous PEEK. We also demonstrate the ability to design and print customized porous implants, specifically for a sheep tibial segmental defect model, based on CT images and using the geometry of triply periodic minimal surfaces (TPMS). Methods. Three porous constructs – a rectilinear pattern and gyroid/diamond TPMSs – were designed to mimic trabecular bone morphology and manufactured via PEEK FFF. TPMSs were designed by altering their respective equation approximations to achieve desired porous characteristics, and the meshes were solidified and shaped using a CAD workflow. Printed samples were mCT scanned to determine the resulting pore size and porosity, then seeded with pre-osteoblast cells for 7 and 14 days. Cell proliferation and alkaline phosphatase activity (ALP) were evaluated, and the samples were imaged via SEM. The structures were tested in compression, and stiffness and yield strength values were determined from resulting stress-strain plots. Roughness was determined using optical profilometry. Finally, our process of porous structure design/creation was modified to establish a proof-of-concept workflow for creating PSIs using geometry established from segmented sheep tibia CT images. Results. ALP activity measurements of the porous PEEK samples at 7 and 14 days were significantly greater than for solid controls (p < 0.001 for all three designs, 14 days). No difference between the porous geometries was found. SEM imaging revealed cells with flat, elongated morphology attached to the surface of the PEEK and into the pore openings, with filopodia and lamellipodia extensions apparent. mCT imaging showed average pore size to be 545 ± 43 µm (porosity 70%), 708 ± 64 µm (porosity 68%), and 596 ± 94 µm (porosity 69%) for the rectilinear, gyroid, and diamond structures, respectively. The average error between the theoretical and actual values was −16.3 µm (pore size) and −3.3 % (porosity). Compression testing revealed elastic moduli ranging from 210 to 268 MPa for the porous samples. Yield strengths were 6.6 ± 1.2 MPa for lattice, 14.8 ± 0.7 MPa for gyroid, and 17.1 ± 0.6 for diamond. Average roughness ranged from 0.8 to 3 µm. Finally, we demonstrated the ability to design and print a fully porous implant with the geometry of a sheep tibia segment. Assessments of implant geometrical accuracy and mechanical performance are ongoing. Discussion. We created porous PEEK with TPMS geometries via FFF and demonstrated a positive cellular response and mechanical characteristics similar to trabecular bone. Our work offers an innovative approach for advancing point-of-care 3D printing and PSI creation

Spinal stenosis is a condition resulting in the compression of the neural elements due to narrowing of the spinal canal. Anatomical factors including enlargement of the facet joints, thickening of the ligaments, and bulging or collapse of the intervertebral discs contribute to the compression. Decompression surgery alleviates spinal stenosis through a laminectomy involving the resection of bone and ligament. Spinal decompression surgery requires appropriate planning and variable strategies depending on the specific situation. Given the potential for neural complications, there exist significant barriers to residents and fellows obtaining adequate experience performing spinal decompression in the operating room. Virtual teaching tools exist for learning instrumentation which can enhance the quality of orthopaedic training, building competency and procedural understanding. However, virtual simulation tools are lacking for decompression surgery. The aim of this work was to develop an open-source 3D virtual simulator as a teaching tool to improve orthopaedic training in spinal decompression. A custom step-wise spinal decompression simulator workflow was built using 3D Slicer, an open-source software development platform for medical image visualization and processing. The procedural steps include multimodal patient-specific loading and fusion of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) data, bone threshold-based segmentation, soft tissue segmentation, surgical planning, and a laminectomy and spinal decompression simulation. Fusion of CT and MRI elements was achieved using Fiducial-Based Registration which aligned the scans based on manually placed points allowing for the identification of the relative position of soft and hard tissues. Soft tissue segmentation of the spinal cord, the cerebrospinal fluid, the cauda equina, and the ligamentum flavum was performed using Simple Region Growing Segmentation (with manual adjustment allowed) involving the selection of structures on T1 and/or T2-weighted scans. A high-fidelity 3D model of the bony and soft tissue anatomy was generated with the resulting surgical exposure defined by labeled vertebrae simulating the central surgical incision. Bone and soft tissue resecting tools were developed by customizing manual 3D segmentation tools. Simulating a laminectomy was enabled through bone and ligamentum flavum resection at the site of compression. Elimination of the stenosis enabled decompression of the neural elements simulated by interpolation of the undeformed anatomy above and below the site of compression using Fill Between Slices to reestablish pre-compression neural tissue anatomy. The completed workflow allows patient specific simulation of decompression procedures by staff surgeons, fellows and residents. Qualitatively, good visualization was achieved of merged soft tissue and bony anatomy. Procedural accuracy, the design of resecting tools, and modeling of the impact of bone and ligament removal was found to adequately encompass important challenges in decompression surgery. This software development project has resulted in a well-characterized freely accessible tool for simulating spinal decompression surgery. Future work will integrate and evaluate the simulator within existing orthopaedic resident competency-based curriculum and fellowship training instruction. Best practices for effectively teaching decompression in tight areas of spinal stenosis using virtual simulation will also be investigated in future work

Demographic changes will increase the number of surgical procedures in the next years. Therefore, quality assurance of clinical processes, such as the reprocessing of surgical instruments as well as intraoperative workflows will be of increasing importance to ensure patient safety. Surgical procedures are often complex and may involve risks for the patient. For fixation of screws, e.g. in case of pedicle screws, osteosynthesis plates or revision joint replacement surgery implants, the application of defined torques may be crucial in order to achieve optimal therapeutic results and minimal complication rates. In many cases a subjective rating of the surgeon is necessary as no adequate instrumentation is available. With the same subjective feeling, hammering or screwing in are performed to implant e.g. the acetabular component in THA. Our actual work is dedicated to the implementation of a functional prototypes of sensor- integrated instruments for specific types of intervention (especially in traumatology) and the evaluation of the sensor integrated surgical instruments in combination with RFID technology for smart process optimisation in the operating room as well as for reprocessing of surgical instruments and surgical management in combination with a knowledge-based planning, control and documentation system. Complementary (preferably wireless) sensors such for instrument identification, tracking or more complex measurements such as forces, torques, temperature or impacts during surgery as well as during reprocessing of reusable instruments could enable computer network based quality assurance in a much broader and comprehensive manner. Within the framework of the OR.NET initiative we follow the approach to integrate wireless sensors for measurement of temperature, force-torque as well as inertial sensors for orientation and impact control, depending on the specific type of application for monitoring of workflows during surgery as well as during reprocessing of reusable instruments and devices. The integration of smart surgical instruments into an open networked operating room based on the open communication standard IEEE 11073 knowledge-based workflow system, can help to improve the process and quality management

INTRODUCTION. Although several meta-analyses have been performed on total knee arthroplasty (TKA) using computer-assisted orthopaedic surgery (CAOS) [1], understanding the inter-site variations of the surgical profiles may improve the interpretation of the results. Moreover, information on the global variations of how TKA is performed may benefit the development of CAOS systems that can better address geographic-specific operative needs. With increased application of CAOS [2], surgeon preferences collected globally offers unprecedented opportunity to advance geographic-specific knowledge in TKA. The purpose of this study was to investigate geographic variations in the application of a contemporary CAOS system in TKA. Materials and Methods. Technical records on more than 4000 CAOS TKAs (ExactechGPS, Blue-Ortho, Grenoble, FR) between October 2012 and January 2016 were retrospectively reviewed. A total of 682 personalized surgical profiles, set up based on surgeon's preferences, were reviewed. These profiles encompass an extensive set of surgical parameters including the number of steps to be navigated, the sequence of the surgical steps, the definition of the anatomical references, and the parameters associated with the targeted cuts. The profiles were compared between four geographic regions: United States (US), Europe (EU), Asia (AS), and Australia (AU) for cruciate-retaining (CR) and posterior-stabilized (PS) designs. Clinically relevant statistical differences (CRSD, defined as significant differences in means ≥1°/mm) were identified (significance defined as p<0.05). Results. For resection parameters, CRSDs were found between regions in posterior tibial slope (PTS), tibial resection depth, as well as femoral flexion for both CR and PS profiles (marked in Table 1). Regarding anatomical references, US was the only region using posterior cruciate ligament (PCL) as the reference for CR resection depth (Table 1). Differences in percentage of preference were found in the anatomical references for tibial varus/valgus, tibial resection depth, femoral varus/valgus, femoral axial rotation, and ankle center (Table 1,2). For surgical steps, EU and AU were found to apply gap balancing technique as a common practice for the PS designs, while for the CR designs, EU and AU considerably adopted this technique (Table 2). For PS designs, EU and AU profiles preferred tibial first in the resection workflow, compared to a more balanced preference for other regions. For CR designs, US profiles were in favour of performing the femoral resection first in the workflow, compared to a strong favouring of tibial first resection workflow in EU and AS Am regions. Discussion. This study demonstrated clinically significant geographic differences may exist in the surgeons' preference of surgical parameters, anatomical references, and surgical workflow steps during TKA. These differences may reflect the geographic variations of surgeon training, surgical philosophy, or the specific characteristics of the patient population, which warrants further investigation. The strength of this study was that it is the first study to date that covered all the available surgical profiles spanning the application history of a specific CAOS system. As such, variation due to the operational differences of multiple systems was avoided. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Introduction. In cementless THA the incidence of intraoperative fracture has been reported to be as high 28% [1]. To mitigate these surgical complications, investigators have explored vibro-acoustic techniques for identifying fracture [2–5]. These methods, however, must be simple, efficient, and robust as well as integrate with workflow and sterility. Early work suggests an energy-based method using inexpensive sensors can detect fracture and appears robust to variability in striking conditions [4–5]. The orthopaedic community is also considering powered impaction as another way to minimize the risk of fracture [6– 8], yet the authors are unaware of attempts to provide sensor feedback perhaps due to challenges from the noise and vibrations generated during powered impaction. Therefore, this study tests the hypothesis that vibration frequency analysis from an accelerometer mounted on a powered impactor coupled to a seated femoral broach can be used to distinguish between intact and fractured bone states. Methods. Two femoral Sawbones (Sawbones AB Europe, SKU 1121) were prepared using standard surgical technique up to a size 4 broach (Summit, Depuy Synthes). One sawbone remained intact, while a calcar fracture approximately 40mm in length was introduced into the other sawbone. Broaching was performed with a commercially available pneumatic broaching system (Woodpecker) for approximately 4 secs per test (40 impactions/sec) with hand-held support. Tests were repeated 3 times for fractured and intact groups as well as a ‘control’ condition with the broach handle in mid-air (ie not inserted into the sawbone). Two accelerometers (PCB M353B18) positioned on the femoral condyle and the Woodpecker impactor captured vibration data from bone-broach-impactor system (Fig1). Frequency analysis from impaction strikes were postprocessed (Labview). A spectrogram and area under FFT (AUFFT) [4] were analysed for comparisons between fractured and intact bone groups using a nested ANOVA. Results. Vibration frequency patterns between respective groups were best observed using an accelerometer positioned on the impaction device rather than on a sawbone (fig1). Qualitative assessment revealed that spectrograms showed no obvious difference for characteristic vibration frequencies between intact and fractured bone groups. A frequency signal at approximately 10kHz was absent for control impactions but present with bone impactions (Fig2). Quantitative assessment revealed AU-FFT was noticeably higher for intact bone groups than fractured bone groups for sampled impactions using a nested experimental design for statistics (p=0.11). Discussion. Our pilot study demonstrates that application of powered impaction combined with vibration frequency analysis has the potential to distinguish between an intact and fractured sawbone in a way that minimises instrumentation footprint and complexity of workflow in OR with a new generation of impaction device targeted at reducing and detecting bone fractures. Further investigation should validate these methods by evaluating the variation with sawbones and simulated bone fractures

In robot-assisted orthopaedic surgery, registration is a key step, which defines the position of the patient in the robot frame so that the preoperative plan can be performed. Current registration methods have their limitations, such as the requirement of immobilisation of the limbs or the line of sight (LOS) issues. These issues cause inconvenience for the surgeons and interrupt the surgical workflow in the operating room. Targetting these issues of current registration methods, we propose a camera-robot registration system for joint replacement. The bone geometry, which is measured directly by a depth camera, is aligned to a preoperatively obtained bone model to calculate the pose of the target. Simultaneously, in order to avoid registration failure caused by LOS interruptions, the depth camera tracks objects that may occlude the target bone, and a robot manipulator is used to move the camera away from the nearest obstacle. The optimal camera motion is calculated based on the position and velocity of the obstacle, which avoids the occlusion efficiently without changing the target position in the camera frame. Inverse kinematics of the robot is used to project the Cartesian velocity of the end-effector into the joint space, with kinematic singularities considered for stable robotic control. An admittance controller is designed as the human-robot interface so that the surgeon can directly set the robot configuration by hand according to the actual environment. Simulations and experiments were conducted to test the performance. The results show that the proposed obstacle avoidance method can effectively increase the distance between the obstacle and the LOS, which lowers the risk of registration failure due to obstacle occlusion. This pilot study is promising in reducing distractions to the surgeon and can help achieve a fluent and surgeon-centred workflow

According to Webster's Dictionary, efficiency is defined as the capacity to produce desired results with a minimal expenditure of energy, money, time, and materials. For a surgeon performing an operative procedure this would mean “skillfulness in avoiding wasted time and effort.” (. www.webster-dictionary.org. ) The essential ingredient to becoming efficient is to promote a culture of efficiency. There are 10 elements: 1) proactive surgeon perspective; 2) effective utilization of preoperative holding area; 3) preoperative planning / templating; 4) development of preference cards; 5) operating room set-up protocols; 6) operating room team concept; 7) streamlined instrument sets; 8) consistent operative workflow; 9) standardised closure / dressings; and 10) prompt and meticulous room turnover. Efficient performance of an operative procedure requires skillfulness in avoiding wasted time and effort. Perioperative efficiencies are optimised by development of “swing,” “flip,” or “double occupancy” criteria, understanding of timing of when to initiate the anesthetic block for the next case, skin closure routine by physician assistant/nurse practitioner/private scrub, and marking the operative site of your first two patients upon arrival to the hospital or surgery center. Utilise a pro-active approach to prepare case carts the day before surgery. The operating room team turns over their own rooms, with a “clean as you go” mentality. Develop a formalised communication process for patient flow issues, such as real-time push-to-talk group calling phones. Determine in advance the number of instrument sets required for the day's caseload to mitigate flash sterilization and decrease room turnover time. The goal of the surgeon is to be out of the operating room for 5 minutes in between cases before the next incision, utilizing that time to enter orders, communicate with the family, dictate, and mark the operative site of the patient who will follow the one in the case about to start. Implant selection can help if consistent. Everyone must know the instrument trays including surgeon, scrubs, and nurses. Minimise both the number of trays and the redundancy of instrumentation. Templating should be done in advance of the day of surgery. Keep your surgery consistent and always deliver your best product. The workflow for inpatient and outpatient surgeries should be the same: same implant, same approach, and same closure. The culture of efficiency requires buy-in by all involved in the operative procedure. Every one entering the operating theatre should have proper body coverage – no hair visible, no nose visible. There should be a strict limit to needless activity: minimum opening of doors, no changing of personnel during an operation, and use of intercom/telephone to request equipment. As the surgeon and the team begin to embrace efficiency, surgical times will decrease. Multiple studies have demonstrated that increased surgical time is associated with a higher incidence of infection. This is secondary to time-dependent contamination of the surgical wound and field. The take home message is to develop and embrace efficiency. Operating room efficiency is the product of multiple factors including preoperative preparation, skilled anesthesia team, motivated operating room staff, choreographed surgery, and well-designed instrumentation. The surgeon is the captain of the ship and the staff follows his or her lead. Your operating room days will flow smoothly. Your operations will proceed with minimal stress. You will spend less time drinking coffee between cases and have more free time at the end of the day. However, most importantly, you will deliver a quality product to your patient

Achieving precise open reduction and fixation of acetabular fractures by using a plate osteosynthesis is a complex procedure. Increasing availability of affordable 3D printing devices and services now allow to actually print physical models of the patient's anatomy by segmenting the patient's CT image. The data processing and printing of the model however still take too much time and usually the resulting model is rigid and doesn't allow fracture reduction on the model itself. Our proposed solution automatically detects relevant structures such as the fracture gaps and cortical bone while eliminating irrelevant structures such as debris and cancellous bone. This is done by approximating a sphere to the exterior surface of a classic segmented STL model. Stepwise, these approximated vertices are projected deeper into any structure such as the acetabular socket or fractures, following a specific set of rules. The resulting surface model finally is adapted precisely to the primary segmented model. Creating an enhanced surface reconstruction model from the primary model took a median time of 42 sec. The whole workflow from DICOM to enhanced printable 3D file took a median time of 13:25 min. The median time and material needed for the prints without the process was 32:25:36 h and 241,04 g, with the process 09:41:33 h and 65,89 g, which is 70% faster. The price of material was very low with a median of 2,18€ per case. Moreover, fracture reduction becomes possible, allowing a dry-run of the procedure and allowing more precise plate placement. Pre-contouring of osteosynthesis plates by using these 3D printouts was done for eleven patients prior to surgery. These printouts were validated to be accurate by three experiences surgeons and compared to classic segmented models regarding printing time, material cost and reduction ability. The pre-contouring of the plates was safely achievable. Our results show that improving the operative treatment with the help of enhanced 3D printed fracture models seems feasible and needs comparably little time and cost, thus making it a technique that can easily integrated into the clinical workflow

Both gap balancing and measured resection for TKA will work and these techniques are often combined in TKA. The only difference is really the workflow. The essential difference in gap balancing is that you determine femoral component rotation by cutting the distal femur and the proximal tibia, and then using a spacer to determine femoral rotation. I prefer measured resection because I am, for most cases, a cruciate retaining surgeon. It is not ideal to determine femoral rotation based upon a gap balancing if you retain the cruciate. It is also important to maintain the joint line, especially in cruciate retention, in order to reproduce more normal kinematics and balance the knee throughout the range of flexion and extension. It is my opinion that the soft tissue balancing is easier to do with measured resection and the workflow is easier. The sequence of cuts and soft tissue balance is different if one is a gap balancing surgeon. This is more conducive for people who are cruciate substituters, but more difficult in a varus cruciate retaining knee. In that situation, if you determine femoral rotation by gap balancing with the tibia before you have cleared the posterior medial osteophytes in the varus knee, and remove the last bit of meniscus, you could artificially over rotate the femoral component causing posteromedial laxity. The major difference is that cutting the posterior cruciate will open the flexion space and allow the surgeon easier access to the posteromedial corner of the knee before the posterior femoral cut is made. It is also important to remember that in most cases cruciate substitution surgeons will make the flexion space 2 mm smaller than the extension space to compensate for the flexion space opening when the posterior cruciate is cut. The extensor mechanism plays an important role in flexion balance and should only be tested once the patella is prepared and the patella is back in the trochlear groove. I prefer gap balancing in most revision knees as I am virtually always substituting for the posterior cruciate in that case. My technique for measured resection is to assess the character of the knee prior to surgery. Is it varus? Is it valgus? Does it hyperextend? Does it have a flexion contracture? Would the knee be considered tight or loose? I cut the distal femur first, based upon measured resection. I use anatomic landmarks to determine femoral rotation. My most consistent landmark is the transtrochlear line, which is not always from the top of the notch to the bottom of the trochlea. I will use the medial epicondyle and the posterior reference in a varus knee, but not in a valgus knee. The tibial cut, also by measured resection, is easier once the femur has been prepared. The patellar cut is also a measured resection. Having done a preliminary soft tissue balance based upon the deformity, I will then use trial components to finish the soft tissue balance. In summary, both techniques can be used successfully in a cruciate substituting knee, but measured resection, in my opinion, is preferable especially in varus arthritis when the posterior cruciate is retained

The internal fixation of scaphoid bone fractures remains technically difficult due to the size of the bone and its three- dimensional shape. Early rigid fixation, e.g with a screw, has been shown to support good functional outcome. In terms of stability of the fracture, biomechanical studies have shown a superior result with central screw placement in the scaphoid in comparison with an eccentric position, which can lead to delayed or non-union. Image-based navigation could be helpful for these cases. The main limitation of reference-based navigation systems is their dependence on fixed markers like used in modern navigation systems. Therefore it is limited in treatment of small bone fractures. In former experimental studies 20 artificial hand specimens were randomised into two groups and blinded with polyurethane foam: 10 were treated conventionally and 10 were image guided. For trajectory guidance a reduction of duration of surgery, radiation exposure and perforation rate compared to the conventional technique could be found. Accuracy was not improved by the new technique. The purpose of this study was to identify the possible advantages of the new guidance technique in a clinical setting. In this prospective, non-randomised case series we tested the feasibility of the system into the accommodated surgical workflow. There was no control group. Three cases of scaphoid fractures were included. All of the patients were treated with a cannulated screw following K-wire placement via the percutaneous volar approach described. In addition, length measurements and screw sizes were determined using special features of the system. The performing surgeon and two attending assistant doctors (one assisting the surgical procedure, one handling the guidance system) had to rate the system following each procedure via a user questionnaire. They had to rate the system's integration in the workflow and its contribution to the success of the surgical procedure in percentages (0 %: totally unsuccessful; 100 %: perfect integration and excellent contribution). All of the clinical procedures were performed by the same surgeon. The surgeons rated the system's contribution and integration as very good (91 and 94 % of 100 %). No adverse event occurred. An average of 1.3 trials ± 0.6 (1; 2) was required to place the K-wire in the fractured scaphoid bone. The dose-area product was 19 cGycm2 ± 3 (16; 22). The mean incision until suture time was 36.7 min ± 5.7 (30; 40). For clinical cases, the system was integrated and rated as very helpful by users. The system is simple and can be easily integrated into the surgical workflow. Therefore it should be evaluated further in prospective clinical series

Insall, Laskin and others have taught us that the goal of successful total knee replacement (TKR) is to have well fixed and fitted components in a neutral mechanical axis (MA) with balanced soft tissues. Computer and robotic assisted (C-RAS) TKR with real time validation is an excellent tool to help you to attain these goals. Ritter and others have shown higher early failure rates with TKR's where the final alignment is outside a 3-degree window of the neutral MA. Dalury and Schroer have each shown higher early failure rates in TKR's with postoperative instability and or malalignment. C-RAS TKR helps prevent and significantly lowers the number of TKR outliers that may go on to early aseptic loosening and failure as compared with traditional methods. This featured video was created to show how surgeons can benefit from real-time validation and the kinematic data provided during C-RAS. The system helps in their intraoperative decision-making process and then guides them to make precise bone cuts and balance the soft tissue envelope in a very time efficient and highly repeatable fashion. Additionally, imageless C-RAS breaks away from the paradigm of pre-operative MRI or CT scan imaging studies by no longer requiring such costly procedures. This relatively easy, simple to learn, and cost-efficient procedure is a valuable asset in the operating room, for both the surgeon and patient. Furthermore, it is highly customizable and easily integrated into any surgeon's workflow, technique, and exposure. The viewer will learn the C-RAS TKR simple workflow of Tracking, Registration, Navigation, and Validation. The results of the previously published abstract “Influence of Pre-Operative Deformity on Surgical Accuracy and Time in Robotic-Assisted TKA” JA Koenig; C Plaskos; . BJJprocs.boneandjoint.org.uk. 95-B/SUPP28/62 2013, will also be presented at the end of the video. Finally many have argued that C-RAS TKR is an excellent method to teach the “ART of TKR” to young surgeons, residents and students as they can see with real time validation and data the immediate consequences and effects of their intra-operative actions and maneuvers