bluuebunny/crossref_metadata_2025 huggingface dataset:
Heat resistant electronic modules for intelligent medical sterile containers
Authors: Böhler Lukas , Daniol Mateusz , Kleinhans Lukas , Keller Anton , Sroka Ryszard
Published: February 2018

The digitalisation gets more and more important in our daily life. Also in medical technology instruments and devices need to become intelligent and be able to both collect and provide additional data. This research is about the development of an electronic sensor system for sterilisable medical containers. Hereby just a few concepts exist to equip the containers with sensor modules but the high temperature of 135 °C during the sterilisation is still a big challenge.

The objective for this research is to find a heat resistant insulation for an electronic system with a power supply, sensors for both sterilisation and transport and a low power communication module. Furthermore, the thermal energy of the sterilisation shall be used for powering up the system.

In a first step an epoxy resin was used to insulate the electronics and a high temperature battery. By using the temperature sensor of a Bluetooth module the module temperature could be measured during multiple steam sterilisations. Following, a partly insulated thermoelectric generator shall be used to get energy by the achieved temperature difference.

First results show that the used epoxy resin limits the temperature to 81 °C. However, the resin was damaged after 21 sterilisation cycles due to its high mass and entrapped air. Therefore, the insulation needs to be minimized and the electronic components need to be able withstanding higher temperatures. Additionally, insulations with not yet considered materials will be tested. Also the possibility of insulating just heat-sensitive parts like the power elements will be investigated.
Ten year survival of navigation-assisted total knee arthroplasty.
Authors: Jenny Jean-Yves
Published: February 2018

Total knee arthroplasty (TKA) is considered a highly successful procedure. Survival rates of more than 90% after 10 years are generally reported. However, complications and revisions may still occur for many reasons, and some of them may be related to the operative technique. Computer assistance has been suggested to improve the accuracy of implantation of a TKA (Jenny 2005). Short term results are still controversial (Roberts 2015). However, few long term results have been documented (Song 2016). The present study was designed to evaluate the long-term (more than 10 years) results of a TKA which was routinely implanted with help of a non-image based navigation system. The 5- to 8- year of this specific TKA has already been documented (Jenny 2013).

The hypothesis of this study will be that the 10 year survival rate of this TKA will be improved in comparison to historical papers when analyzing survival rates and knee function as evaluated by the Knee Society Score (KSS).
Robotic-Arm Assisted Total Knee Arthroplasty Demonstrated Soft Tissue Protection
Authors: Hampp Emily , Bhowmik-Stoker Manoshi , Scholl Laura , Otto Jason , Jacofsky David , Mont Michael
Published: February 2018

Total knee arthroplasty (TKA) typically addresses end-stage osteoarthritis. While TKA procedures have demonstrated clinical success, occasionally intraoperative complications can occur. This cadaver study examined the potential benefits of soft tissue protection in robotic-arm assisted TKA (RATKA). Six cadaver knees were prepared using RATKA by a single surgeon from a high-volume TKA joint center with no former clinical robotic experience, and compared to seven manually performed cases as a control. The presence of soft tissue disruption was assessed by having the surgeon perform visual evaluation and palpation of the medial collateral ligament (MCL), lateral collateral ligament (LCL), posterior cruciate ligament (PCL), and the patellar ligament after the procedures. The amount of tibial subluxation and patellar eversion was recorded for each case.

For all RATKA cases, there was no visible evidence of disruption of any of the ligaments. All RATKA cases were successfully left with a bone island on the tibial plateau, which protected the PCL. Tibial subluxation and patellar eversion were not required for visualization. In two of the seven MTKA cases, there was slight disruption noted of the PCL, although this did not lead to any apparent change in the functional integrity of the ligament. All MTKA cases required tibial subluxation and patellar eversion to achieve optimal visualization.

Aspects of soft tissue protection were noted in this cadaver study for RATKA. Standard retraction techniques during cutting are recommended. This is the first study to have soft tissue injury parameters assessed for RATKA, and may serve as a platform for future studies.
Measuring Pelvic Tilt with the Use of a Navigated Smart-Devices Based Ultrasound System
Authors: Martin Tobias , Alk Andreas , Kozak Josef
Published: February 2018

The key for a successful total hip replacement (THR) and the longevity of the implant is the correct alignment of the acetabular cup which is to be considered as the most critical component. The alignment of the cup is defined with respect to anterior pelvic plane (APP). The APP defines the reference for the anteversion and inclination angles which sets the basis for the correct alignment of the implant. The angle of the plane is created by three distinct anatomical landmarks which are represented by two anterior superior iliac spines (ASIS) and the symphysis pubis. The angle of the APP in respect to the coronal plane defines the pelvic tilt (PT) which can be anterior or posterior. The rotation of the pelvis highly depends on the individual anatomy of the subject. This means that a neutral pelvic tilt (PT) in supine position is rarely observed and also may be dissimilar in standing position. In this paper we present a non-invasiveness and cost-effective prototype for measuring the patient-specific PT under the use of a navigated smart-device based ultrasound system for supporting surgery planning. In view of the non-invasiveness method the system can be used to measure pre- and postoperative pelvic orientation. With the use of an artificial hip reference model different cases were measured. The computed results look very promising with a standard deviation of ±1°.
Sensor Integrated Instruments for Surgical Quality Assurance and Process Monitoring
Authors: Strathen Benjamin , Janß Armin , Gödde Peter , Radermacher Klaus
Published: February 2018

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 optimization 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.
“HADO” as Techno Sports was born by the fusion of IT technology and sports
Authors: Araki Hitoshi , Fukuda Hiroshi , Motoki Takuma , Takeuchi Tsuyoshi , Ohta Naoki , Adachi Ryosuke , Masuda Hiroshi , Kado Yasuyuki , Mita Yoshiki , Mizukami Daisuke , Kakeya Nayu
Published: February 2018

"HADO" is the combination of Augmented Reality (AR) technology, motion sensor, Head-mounted display (HMD), smartphone, and sports that creates a whole new experience that we call "Techno Sports". By wearing the arm sensor in the arm and HMD to the head, adding the AR technology, HADO actualize magical worlds everyone dreams of as a child. Shoot energy balls to smash opponents and use the shield to prevent opponent's attacks!! Think strategic, move like a lightning, and coordinate team play to flight your opponents. This is a HADO Players vs. Players battle!!
Pelvic Rotation and Inclination Affect Reliability of Sagittal Pelvic Alignment and Anterior Pelvic Plane Angle Measured by EOS System
Authors: Okamoto Masashi , Tokunaga Kunihiko
Published: February 2018

The Difficulties to obtain acceptable pelvic reference points on bi- planar X-ray images for EOS measurements change as the patient’s pelvis rotated or inclined. The aim of this study was to clarify the effects of pelvic Z-axis rotation (rotation) and X-axis rotation (inclination) on the measurement values of SS, PT, and APP angle by using of EOS. Methods: We obtained anteroposterior and lateral X-ray images of a trunk phantom which was rotated and inclined in standing position by using of the EOS. Sacral slope (SS) and pelvic tilt (PT) as parameters to judge patient’s pelvic alignments by spinal surgeons, and anterior pelvic (APP) angle as a reference to decide patient’s pelvic alignments by hip surgeons were measured with the EOS software. The values of SS and PT and APP angle were compared in the phantom rotation and inclination. Results: PT showed small changes when the phantom was rotated, however, SS decreased and APP angle increased when the phantom was rotated. The values of SS and PT dispersed at 300 rotation among each inclination. APP angle dispersed at -15o and 30o of rotation among each inclination. Conclusion: Measurement variations of SS and PT were small amount under 15 degrees of rotation and inclination. On the contrary, APP angles showed greater variations when the phantom was rotated and inclined. Proper positioning of subjects, by reducing rotational effects, is important to get constant reproducible measurements, even if we use EOS system.
Clinical and Radiological Results from Reconstruction of Massive Acetabuar Defects Using 3D Printed Trabecular Titanium Implants
Authors: Henckel Johann , Durand-Hill Matthieu , Noory Sabir , Skinner John , Hart Alister
Published: February 2018

Additive manufacturing has enabled a radical change in how surgeons reconstruct massive acetabular defects in revision hip surgery. We report on the early clinical and radiological results from our methods for surgical planning, design, and implantation of 3D printed trabecular titanium implants in a cohort of patients with large unclassifiable pelvic defects.

We set up a prospective investigation involving 7 consecutive patients. Inclusion criteria was the following: 1) A history of previous total hip replacement; and 2) Current imaging showing at least a Paprosky 3B defect. Planned acetabular inclination and version was 40° and 20° respectively. Post operatively all patients had a CT scan which was analysed with software to determine component position and compared to planned. Outpatient review was done at 2 weeks (For wound), 6 weeks (for weight bearing and fixation) and 52 weeks (for fixation and infection) post-operative.

3 Themedianageatsurgerywas:65years(40-78).Themedianbonedefectvolumewas140cm .Median

surgery length was 5.2 hours (3-6.25). Median blood loss was 1300mL (450- 2000). Radiologically, components were stable and no screw breakages were identified. Achieved inclination was 41.0° (29.0- 55.6) and achieved version was 15.8° (3.8-43.6). Median Oxford Hip score improved from 9 (2-44) to 25 (18-32).

We have demonstrated a new series of pre, intra and post-operative methods for reconstruction of unclassifiable acetabular bony defects. Initial clinical and radiological results are excellent considering the severity of the bony defects. We recommend the use of our or similar methods when trying to reconstruct these defects.
A High Immersive Infinity Walking System with HMD and Load Balance
Authors: Yamamoto Tomoyuki , Seya Yasuhiro , Saito Mitsuyuki , Kobayashi Yasuhide , Wakita Wataru
Published: February 2018

We propose a low-cost and high immersive infinity walking system with HMD and all directional load balance, which enables to present walking sensation for a user in VR environments. By using a device supporting user’s thighs during walking, our system enables a user to shift the center of gravity of body toward any walking direction like dynamic walking in real environments. Although many studies have proposed infinity walking systems based on a treadmill, a stepping method, a sliding method, and etc., there are several limitations to use these systems in practice. For example, the treadmill-based walking system is large and high-cost. The stepping method is known to be a low-cost method, but it is difficult for a user to shift the center of gravity of body toward a walking direction. The walking sensation provided by the sliding method may not be natural, because user’s feet move backward during walking. Therefore, we develop a low-cost and high immersive infinity walking system with HMD and all directional load balance that can provide the realistic walking sensation with a user.
Augmented Marker Tracking for Peri-acetabular Osteotomy Surgery: A Cadaver Study
Authors: Pflugi Silvio , Lerch Till , Vasireddy Rakesh , Boemke Nane , Tannast Moritz , Ecker Timo Michael , Siebenrock Klaus , Zheng Guoyan
Published: February 2018

Purpose. To validate a small, easy to use and cost-effective augmented marker-based hybrid navigation system for peri-acetabular osteotomy surgery.

Methods. A cadaver study including 3 pelvises (6 hip joints) undergoing navigated PAO was performed. Inclination and anteversion of two navigation systems for PAO were compared during acetabular reorientation. The hybrid system consists of a tracking unit which is placed on the patient’s pelvis and an augmented marker which is attached to the patient’s acetabular fragment. The tracking unit sends a video stream of the augmented marker to the host computer. Simultaneously, the augmented marker sends orientation output from an integrated inertial measurement unit (IMU) to the host computer. The host computer then computes the pose of the augmented marker and uses it (if visible) to compute acetabular orientation. If the marker is not visible, the output from the IMU is used to update the orientation. The second system served as ground truth and is a previously developed and validated optical tracking-based navigation system.

Results. Mean absolute difference for inclination and anteversion (N = 360) was 1.34 degrees and 1.21 degrees, respectively. The measurements from our system show a very strong correlation to the ground-truth optical tracking-based navigation system for both inclination and anteversion (0.9809 / 0.9711).

Conclusion. In this work we successfully demonstrated the feasibility of our system to measure inclination and anteversion during acetabular reorientation.
Evaluation of 2D Biomechanical Models of the Knee of One-Leg Stand for Total Knee Arthroplasty Planning
Authors: Asseln Malte , Eschweiler Jörg , Kiliclar Anika , Kutzner Ines , Bergmann Georg , Radermacher Klaus
Published: February 2018

Biomechanical models of the knee have the potential to predict joint mechanics and improve the therapeutic outcome. In case of total knee arthroplasty (TKA) knowledge on post-operative acting joint forces and its consideration in pre-operative planning might increase implant longevity and patient satisfaction. The goal of this study was to evaluate 2D biomechanical models of the knee suitable for pre-operative TKA planning and to validate them based on in vivo measurements of 9 patients treated with instrumented knee implants.

An extensive literature research on 2D biomechanical models of the knee with the requirement that patient-specific model adaption can be performed with data available in the conventional clinical workflow revealed the models of Maquet and Minns. Both models require one-leg stand AP long-leg radiographs and they output the resultant tibiofemoral joint force. For model validation, data from the freely accessible OrthoLoad database (www.orthoload.com) containing forces acting in orthopaedic implants have been used.

Looking at the results, Minns’s model was in the same range as the reference forces (deviation: -55 %BW to +80 %BW) as well as Maquet’s (deviation: -80 %BW to +50 %BW). Overall, the root-mean-square error (RMSE) was smallest for Minns’ model (48.36 %BW against 51.48 %BW). The patient-specific adaptation process plus simulation took 7 to 8 minutes making the models applicable in the conventional clinical workflow with acceptable costs.

In terms of clinical application, the models’ output might be consulted, e.g. to minimize the magnitude of the resultant joint force, target a specific orientation or load distribution in order to consider mechanical factors which might be associated with premature implant failure.
Smart Device Based Application for Rod Determination in Minimal Invasive Spine Surgery
Authors: Alk Andreas , Martin Tobias , Kozak Josef
Published: February 2018

In orthopaedic spine surgery pedicle screw systems are used for stabilisation of the spine after injuries or disorders. With an percutaneous operation method surgeons are faced with huge challenges compared to an open surgery, but it`s less traumatic and the patient benefits with a faster rehabilitation and less traumatic injuries. The screw positions and the required rod dimensions for the stabilizing connection between the screws are hard to define without an open view on the operating field. Because of these facts a new smart device based system for rod shape determination was invented. Therefore, an application was developed, which integrates a localizer module to get the position data of the pedicle screws, with help of rigid bodies placed on top of the pedicle screws down-tubes. An algorithm was developed to choose the best fitting rod to connect the pedicle screws with help of calculating the rod length and the rod radius. The system was tested in a test scenario where four pedicle screws were drilled into a wooden plate. The positions of the screws were adjusted to fit a curved and a straight rod. In the test scenario the application chose always the rod correctly.
Morpho-Functional Analysis of Knee Implant Design for Total Knee Arthroplasty on the Example of the Trochlear Groove Orientation
Authors: Asseln Malte , Verjans Mark , Zanke Darius , Radermacher Klaus
Published: February 2018

Total knee arthroplasty (TKA) is widely accepted as a successful surgical intervention to treat osteoarthritis and other degenerative diseases of the knee. However, present statistics on limited survivorship and patient-satisfaction emphasize the need for an optimal endoprosthetic care. Although, the implant design is directly associated with the clinical outcome comprehensive knowledge on the complex relationship between implant design (morphology) and function is still lacking.

The goal of this study was to experimentally analyze the relationship between the trochlear groove design of the femoral component (iTotal CR, ConforMIS, Inc., Bedford, MA, USA) and kinematics in an in vitro test setup based on rapid prototyping of polymer-based replica knee implants.

The orientation of the trochlear groove was modified in five different variations in a self-developed computational framework. On the basis of the reference design, one was medially tilted (-2°) and four were laterally tilted (+2°, +4°, +6°, +8°). For manufacturing, we used rapid prototyping to produce synthetic replicates made of Acrylnitril-Butadien-Styrol (ABS) and subsequent post-processing with acetone vapor. The morpho-functional analysis of the replicates was performed in our experimental knee simulator. Tibiofemoral and patellofemoral kinematics were recorded with an optical tracking system during a semi-active flexion/extension (~10° to 90°) motion.

Looking at the results, the patellofemoral kinematics, especially the medial/lateral translation and internal/external rotation were mainly affected. During low flexion, the patella had a more laterally position relative to the femur with increasing lateral trochlear orientation. The internal/external rotation initially differentiated and converged with flexion. Regarding the tibiofemoral kinematics, only the tibial internal/external rotation showed notable differences between the modified replica implants.

We presented a workflow for an experimental morpho-functional analysis of the knee and demonstrated its feasibility on the example of the trochlear groove orientation which might be used in the future for comprehensive implant design parameter optimization, especially in terms of image based computer assisted patient-specific implants.
The interleaved partial active shape model search (IPASM) algorithm – Preliminary results of a novel approach towards 3D ultrasound-based bone surface reconstruction
Authors: Hänisch Christoph , Hohlmann Benjamin , Radermacher Klaus
Published: February 2018

In applications such as biomechanical simulations or implant planning, bone surfaces of the knee are most often reconstructed from computed tomography or magnetic resonance imaging data. Here, ultrasound (US) might serve as an alternative imaging modality. However, established methods cannot directly be transferred to US due to differences in imaging quality and underlying physics.

In this paper, we present a generalisation of the well-known active shape model search algorithm (ASM) that allows for segmenting various structures in US volume images that are too large to be captured with a single recording. The multi-view segmentation approach uses a-priori knowledge in the form of a statistical shape model (SSM) as is the case with the classical ASM. This allows to extrapolate missing information and to generate shapes that comply with the underlying distribution of some training data. The main differences are, however, that the SSM is not only adapted to a single image but to multiple images and that the adaption process is interleaved. As a result, within each iteration the surface information of all sub-volumes is propagated and used in all subsequent steps.

In-silico tests were conducted to investigate how this algorithm would perform in real tracked US data. US volume images were split in slightly overlapping sub-volumes, noise was added, and the alignment was distorted. We could show that the algorithm is capable of reconstructing shapes in the lower millimetre range and for some cases even with submillimetric accuracy. The algorithm is hardly affected by orientation errors below 5 degrees and displacement errors below 5 mm; above these limits, the average absolute SDE as well as its associated variance increases.
Patient specific instrumentation influences hemoglobin decrease after total knee replacement.
Authors: Cucchi Davide , Zanini Beatrice , Ferrua Paolo , Compagnoni Riccardo , Menon Alessandra , Randelli Pietro
Published: February 2018

Patient Specific Instrumentation (PSI) may contribute to reduce blood loss after total knee replacement (TKR) by avoiding violation of the medullary canal. The purpose of the study was to compare the hemoglobin (Hb) decrease in two groups of patients undergoing TKR with PSI and conventional instrumentation.

Pre- and post-operative blood samples were collected for twenty-two patients randomly assigned to receive a PSI-assisted or conventional TKR. Post- to preoperative Hb difference was calculated.

A significant difference in Hb reduction in favor of the PSI group was registered on the last day of stay but not on the previous post-operative days: these promising results suggest a beneficial effect of PSI in blood loss reduction. PSI may hence be considered among the strategies available to control and reduce blood loss related to TKR.
Real-Time in-Vitro Evaluation of Knee Kinematics Using Enriched Computed Tomography Data
Authors: Verstraete Matthias , Arnout Nele , De Baets Patrick , Vancouillie Thibeau , Van Hoof Tom , Victor Jan
Published: February 2018

In vitro evaluation of knee kinematics remains an essential part during pre-clinical testing of new implants and surgical procedures. To assess the kinematics, markers are rigidly attached to the bone segments and tracked using infrared cameras. Subsequently, the position of the markers relative to the bone is determined using computed tomography (CT). Although the accuracy of the aforementioned, CT-based method is not doubted, no real-time information is provided. Therefore, this paper presents a real-time method that uses a registration phase in combination with a pre-operative CT scan to determine the location of the bone relative to the markers. During this registration phase, the bone surface location is identified touching surface points with a tracked pen. The kinematic parameters obtained using this real-time method is compared to the golden standard, CT-based, method. Under optimal conditions, rotational and translational differences around 1mm and 1degree are obtained. This is in the range of the inter- and intra- observer variability in determining the landmarks used for these kinematic calculations. It is therefore concluded that the accuracy of the real-time method allows effectively evaluating the knee kinematics in six degrees of freedom.
PSI for Dog Knee Replacement
Authors: Hafez Mahmoud , Moghny Ahmed Abdel
Published: February 2018

Total knee replacement is the standard treatment for advanced knee osteoarthritis. An improved method of treating an osteochondral defect for knee osteoarthritis of dogs is provided, which is a composite tissue for treating or preventing a disease, disorder, or condition associated with an osteochondral defect with new technique. The new technique of custom made instruments and implants for dog and small animals is applied for different breeds of dogs regardless of their sizes and weights. The tool is a custom made instruments, which is based on capture of image based (CT or computed X-ray) to be transferred to electronic 3D model and apply 3D preoperative planning to design the tools are used to perform the knee surgery.
Concepts for Developing Interoperable Software Frameworks Implementing the New IEEE 11073 SDC Standard Family
Authors: Besting Andreas , Stegemann Dominik , Bürger Sebastian , Kasparick Martin , Strathen Benjamin , Portheine Frank
Published: February 2018

The long overdue IEEE 11073 Service-oriented Device Connectivity (SDC) standard proposals for networked and surgical devices provide vendor-independent interoperability and therefore room for improved workflow and new functionality in the operating room. Research and development in this domain remain also highly topical in orthopaedic surgery. Due to the novelty and complexity of the SDC standard family, there is currently a lack of open source public implementations. Such implementations have to overcome several non-trivial challenges, mainly because the complexity of the standards has to be reflected in the software design and implementation. The SDC standard family comes in three different parts and all three standard proposals must be considered when designing and implementing standard conform device communication. In this work, we address these challenges and discuss and compare two design approaches for different programming languages (C++ and Java). Suitable software engineering principles are used to ensure a clean design approach. Practical guidelines are given on how to integrate existing third party components and tools in the framework and the development process, respectively. General feasibility is demonstrated by outlining interoperability between two software frameworks developed using different design concepts.
The surgeon plays an important role in size planning with patient specific instrumentation for total knee replacement.
Authors: Cucchi Davide , Compagnoni Riccardo , Ferrua Paolo , Menon Alessandra , Randelli Pietro
Published: February 2018

Component position and sizing in total knee replacement (TKR) could be improved by patient specific instrumentation (PSI). The purpose of the study was to evaluate the reliability of the manufacturer plan in predicting final component sizes for TKR.

Forty-five TKRs were prospectively enrolled and data on component size were recorded from the initial manufacturer’s proposal, the final plan modified after surgeon’s and from the actually implanted prostheses.

Pre-operative modifications were required in more than 50% of the cases, with the tibial tray size requiring more frequent changes. The surgeon’s planning showed a significantly higher accuracy than the manufacturer’s one regarding tibial tray size (p < 0.05) but not femoral components size (p: n.s.). Careful evaluation by an experienced knee surgeon is recommended when planning TKR with PSI.
Comparison of Outcome and Gait Analysis after Robotic Total Knee Arthroplasty Between Mechanical and Kinematic Knee Alignment methods with and Average 8 Years Follow Up
Authors: Seon Jong-Keun , Song Eun-Kyoo , Lee Dong-Hyun , Yeo Je-Hyoung
Published: February 2018

Background: There are limited previous findings detailed biomechanical properties following implantation with mechanical and kinematic alignment method in robotic total knee arthroplasty (TKA) during walking. The purpose of this study was to compare clinical and radiological outcomes between two groups and gait analysis of kinematic, and kinetic parameters during walking to identify difference between two alignment method in robotic total knee arthroplasty.

Methods: Sixty patients were randomly assigned to undergo robotic-assisted TKA using either the mechanical (30 patients) or the kinematic (30 patients) alignment method. Clinical outcomes including varus and valgus laxities, ROM, HSS, KSS and WOMAC scores and radiological outcomes were evaluated. And ten age and gender matched patients of each group underwent gait analysis (Optic gait analysis system composed with 12 camera system and four force plate integrated) at minimum 5 years post-surgery. We evaluated parameters including knee varus moment and knee varus force, and find out the difference between two groups.

Results: The mean follow up duration of both group was 8.1 years (mechanical method) and 8.0 years (kinematic method). Clinical outcome between two groups showed no significant difference in ROM, HSS, WOMAC, KSS pain score at last follow up. Varus and valgus laxity assessments showed no significant inter-group difference. We could not find any significant difference in mechanical alignment of the lower limb and perioperative complicatoin. In gait analysis, no significant spatiotemporal, kinematic or kinetic parameter differences including knee varus moment (mechanical=0.33, kinematic=0.16 P>0.5) and knee varus force (mechanical=0.34, kinematic=0.37 P>0.5) were observed between mechanical and kinematic groups.

Conclusions: The results of this study show that mechanical and kinematic alignment method provide comparable clinical and radiological outcomes after robotic total knee arthroplasty in average 8 years follow-up. And no functional difference were found between two knee alignment methods durning walking.
Knee Periprosthetic Infections: CAOS Use in One Stage Procedures
Authors: Gérard Giordano
Published: February 2018

INTRODUCTION

The results of TKA revisions are less good than a primary TKA (1). The TKA revision frequency increases and we must prepare the next standard of these surgeries (4).The aim of this study was to evaluate the CAOS / one stage strategy to treat the knee PJIs (2, 3).

MATERIALS

In this prospective study, between September 2011 and december 2014, 41 patients treated for chronic knee PJI in a one stage revision. An imageless CAOS system (ExactechGPS, Blue-Ortho, Gieres) was used with a personnalized profile. All surgeries were performed with the same protocole and by using the same Optetrak CC knee components (Exactech, Gainesville, FL). All operations were performed by a single senior surgeon.

Indications for the revision TKA were (1) revision of a primary TKA or unicondylar knee arthroplasty (n=27) or (2) revision of revisionTKA (n=15).

The measurement of the HKA angle, the Oxford score and the ROM were evaluated pre and post-operatively.

RESULTS

27 males and 14 females with an average age of 71 years old (55-87) were treated for a PIJ (1 unicompartimental prosthesis, 26 TKA and 15 RTKA). The mean follow-up was 41 months (30 months - 6 years). The average time of surgery was 135 mn (120-195) for an average hospitalisation duration of 10 days (7-16). No postoperative outliers were reported (mean preop.: -1,6°+/_-5,1° - Post-op. -0,3°+/_ -1,4°). The average ROM were 115° (90-130°) (Fig. 1). The rate of success for the infection was 92,7%. We report no specific CAS complications and all the navigations were finalized. In this series of complex cases, the rate of infection healing is 92,7%.

DISCUSSION

Using CAOS is a safe option with no specific complication. Combined with one stage procedures, it should be a optimal medicoeconomical strategy for Knee revisions.

This first series initiated the « GPS RTKA » project to create a dedicated software evaluated since January 2016 with immediate very good functional results and no complications.

2002;(404): 7-13
Computer navigated reduction of scaphoid non-unions and displaced scaphoid fractures- a cadaveric study
Authors: Mak Michael Chu-Kay , Chui Elvis Chun-Sing , Tse Wing-Lim , Ho Pak-Cheong
Published: February 2018

Introduction

Scaphoid non-union results the typical humpback deformity, pronation of the distal fragment, and a bone defect in the non-union site with shortening. Bone grafting, whether open or arthroscopic, relies on fluoroscopic and direct visual assessment of reduction. However, because of the bone defect and irregular geometry, it is difficult to determine the precise width of the bone gap and restore the original bone length, and to correct interfragmentary rotation. Correction of alignment can be performed by computer-assisted planning and intraoperative guidance. The use of computer navigation in guiding reduction in scaphoid non-unions and displaced fractures have not been reported.

Objective

We propose a method of anatomical reconstruction in scaphoid non-union by computer-assisted preoperative planning combined with intraoperative computer navigation. This could be done in conjunction with a minimally invasive, arthroscopic bone grafting technique.

Methods

A model consisting of a scaphoid bone with a simulated fracture, a forearm model, and an attached patient tracker was used. 2 titanium K-wires were inserted into the distal scaphoid fragment. 3D images were acquired and matched to those from a computed tomography (CT) scan. In an image processing software, the non-union was reduced and pin tracts were planned into the proximal fragment. The K-wires were driven into the proximal fragment under computer navigation. Reduction was assessed by direct measurement.

These steps were repeated in a cadaveric upper limb. A scaphoid fracture was created and a patient tracker was inserted into the radial shaft. A post-fixation CT was obtained to assess reduction.

Results and Discussion

In both models, satisfactory alignment was obtained. There were minimal displacement and articular stepping, and scaphoid length was restored with less than 1mm discrepancy. This study demonstrated that an accurate reduction of the scaphoid in non-unions and displaced fractures can be accurately performed using computed navigation and computer-assisted planning. It is the first report on the use of computer navigation in correction of alignment in the wrist.
Ten year survival of navigation-assisted unicompartmental knee arthroplasty.
Authors: Jenny Jean-Yves
Published: February 2018

The survival rate of navigation-assisted unicompartmental knee arthroplasty when mechanical revision was considered as the end-point was 94% after 10 years. These figures compares favorably with previously published literature about conventional implantation. Longer follow-up is required to prove superiority of any technique.
Accuracy investigation of dual mode markers for navigated dental implant surgery with a new 3D realtime navigation system DENACAM
Authors: Hemm Simone , Böhringer Stephan , Garnier Quentin , Breitenstein Michael , Minonzio Claudio , Berlinghoff Frank , Jürgens Philipp , Schkommodau Erik
Published: February 2018

Dental implants are in 96% positioned free hand including a risk of suboptimal placement. A miniaturized navigation system has been developed to overcome these limitations by fixing two stereo cameras to the drill to guide the surgeon during implant insertion. The aim of the present study was to develop and analyse a dual-mode marker with a highly precise, high contrast optical pattern, visible by the camera system, on a precise substrate clearly identifiable on Cone Beam CT (CBCT) images and sterilisable. The marker was developed with a laser engraved optical pattern brought to a ceramic substrate containing two holes to ensure clear identification of the position of the marker within CBCT images.

The substrate dimensions were verified with a micrometer gauge and compared to the expected tolerances. The position and angular error of the optical pattern on the substrate was analysed on optical microscope images. Six markers were exposed to 20 cleaning and steam sterilization cycles and changes were analysed on optical and scanning electron microscope (SEM) images. Energy dispersive X-ray spectroscopy (EDX) analysis was performed to study the percentage composition of the different elements.

Substrate dimensions and angular errors remained always within the defined tolerances. Positioning errors were higher than the tolerances for some of the measurements. The error distribution indicates a systematic error. Results were reproducible over the samples. No changes could be observed visually on the optical microscope images between the initial marker and the 20th sterilization cycle. EDX results show slight percentage variations of the different elements between the different cycles. Fluctuations were most important for the carbon-content.

A dual mode marker could be developed with a very accurate optical pattern very precisely positioned on a ceramic substrate making any marker calibration procedure un- necessary. Precision analysis confirmed a reproducible position of the pattern on the substrate, indicating a stable and robust process. Systematic errors can be corrected directly at the used Laser system. Cleaning and sterilization tests confirmed the stability of the dual-mode marker after cleaning and sterilization. The present study has shown that highly accurate, high contrast and robust markers can be manufactured using laser- engraving technology on ceramic substrates.
Design of Flexible Implants for Preservation of Physiological Mobility Exploiting Additive Manufacturing
Authors: Kimm Martin , Jauer Lucas , Hinke Christian , Schleifenbaum Johannes Henrich , Poprawe Reinhart
Published: February 2018

Due to tumors or bone fractures caused by high mechanical impact, the affected tissue has to be removed. The implantation of a stabilizing replacement is a common solution for defect bridging and support of bone ossification. Preserving the physiological mobility after the treatment could prevent stress shielding or overload of the surrounding muscles and ligaments. [1]

In case of a critical vertebral body defect, the body and its attached disks have to be removed. Thereafter the adjacent vertebral bodies are braced together resulting in limited physiological spine movability. A flexible implant adapted to and preserving the patient-specific physiological spine mobility would be a desirable solution. [2] [3]

To realize such an implant additive manufacturing (AM) can be used as a key technology. AM offers the following advantages: The build-up of almost any desired complex geometry shape, without additional costs. A monolithic geometry with enhanced functionalities combined in only one part and one material. A cost-efficient implant individualization based on patient specific requirements. [4]

Relating to flexibility, the integration of solid state hinges tailored to the patient specific physiological mobility is possible. Hereby, assembly work is neglectable and abrasion will be prevented due to the absence of friction partners. A challenge to overcome will be the durability of the design. It is limited by the fatigue of the material caused by implant motion.
Change in pelvic sagittal tilt after corrective long fusion of spine
Authors: Tamura Kazunori , Hamada Hidetoshi , Takao Masaki , Sakai Takashi , Kaito Takashi , Sugano Nobuhiko
Published: February 2018

The individual pelvic sagittal inclination (PSI) is an issue for cup alignment in total hip arthroplasty (THA). The pelvic position in supine or functional pelvic plane in supine have been recommended by many reports while some consider a standing pelvic position as the reference to aim an optimal cup alignment. PSI changes in various postures and even in the same posture, aging change it due to spinal degeneration and muscle weakness. The chronological PSI change is larger in standing than that in supine. It is expected that PSI in standing position may improve when spinal long fusion was performed.

Therefore, the purpose of this study was to evaluate the change of PSI between pre- and post- corrective long fusion for adult spinal deformity (ASD). Total eight patients underwent corrective surgery for ASD between May 2014 and October 2016 were the subjects of this study. All are females with the average age of 70 years. There were two cases that underwent bilateral THA before spine surgery. The anterior pelvic plane (APP) through the most anterior aspect of the pubic tubercle and bilateral anterior superior iliac spines (ASISs) was used to measure PSI, which was defined as the angle between the APP and the vertical axis on the sagittal plane DRR. In addition, we measured the cup anteversion in two THA cases by using viewer software. The mean change in the preoperative PSI from supine to standing was 17° posteriorly. The mean change in the supine PSI from pre- to post-operation was 6.9° anteriorly, and that in the standing PSI was 17° anteriorly. The mean change in the postoperative PSI from supine to standing was 6.7° posteriorly. When we measured PSI on standard AP radiographs of the pelvis in two patients who underwent THA, the mean change in postoperative PSI from supine to standing was less than 3°.The mean change in cup anteversion on supine AP radiographs were 2.7°. As we expected, the change in PSI from supine to standing position was reduced by performing corrective surgery. In this study, the mean change of radiographic cup anteversion in supine after corrective long fusion was 2.7°and PSI in standing changed into the direction which reduce posterior impingement and anterior dislocation. Although the change in PSI after corrective spine surgery heavily depends on the spine surgeon’s philosophy of correction, corrective spine surgery should have a positive effect on cup alignment in standing and little influence on cup alignment in supine.
Patient-Specific Templates for Pedicle Screw Insertion in Spinal Fixation Surgery
Authors: Hafez Mahmoud , Fouda Mohamed
Published: February 2018

The increased use of pedicle screws in scoliosis creates a challenge for accurate and safe placement of

screw within the pedicle during the scoliosis surgery. Patient-specific templates (PST) is a novel

method to guide the surgeons for allocating and detecting the positions and trajectories of pedicle

screws in scoliosis surgery. Based on CT-scans and according to certain protocol, this technique will

allow the surgeon to construct a 3D model of spine and present the stage and vertebrae which contain

the most deformed bone. With preplanned surgery on specific software, we can develop an accurate

and safe position of pedicle screws and its trajectories. This method has the ability to customize the

placement and the size of each pedicle screw based on the unique morphology and landmarks of the

vertebrae.
Superhuman Sports Games in Laval Virtual
Authors: Ando Ryoichi , Orikasa Mai , Takeda Minato , Hayakawa Hirohiko , Sato Kosuke , Uebayashi Isao , Minamizawa Kouta , Inami Masahiko
Published: February 2018

We propose to organize a Superhuman Sports Games1 in Laval Virtual. Superhuman Sports is a new form of sports based on the human-machine integration technology that provides new experiences by augmenting our body. Through superhuman sports experiences, people can realize what when our body and machine integrate naturally, human can overcome individual physical differences, and simultaneously, people can believe human can exceed our physical limitations. For this event, we prepared 3 games to provide physical augmentation experiences. Bubble Jumper augments our jumping function and shock absorption function without using any motors, Sli-de-rift adds new foot function with assist motor and Omni wheels, and Carry Otto augments running with in wheel motor.
Fluoroscopy-based laser projection system for surgical guidance and its calibration methods
Authors: Joung Sanghyun , Lee Hyunwoo , Park Chul-Woo , Oh Chnag-Wug , Park Il-Hyung
Published: February 2018

We have developed a laser projection system, which can project laser on corresponding position to surgical planning drawn at a fluoroscopic image without an optical tracking system. In this paper, we introduce a spatial calibration method between a laser module and a fluoroscope for the laser projection and evaluate its accuracy with a mimic experimental system. The experimental system consists of a laser module, a distance measurement unit and a CCD camera. The laser modules can project arbitrary line on surface by reflecting a point source laser with two galvanometers. We designed a calibration phantom by combining a collimator for accurate laser pattern positioning and stainless steel ball arrays for calculation of an extrinsic parameter of a C-arm fluoroscopy. We set a projection plane having ruler in 400mm distance from the CCD camera, and set 54 points on the screen. The laser module projects points with respect to the set points, and a distance error between set points and projected points and angular error are calculated. The distance errors is 1.5±1.9 mm (average ± standard deviation). Maximum error was 7.5 mm. Angular error was smaller than 2 degrees. The laser projection system and its calibration method shows clinically acceptable accuracy and the clinical application is the next step.