The Effects of Tibial Tray Rotation and Posterior Slope on Knee Kinematics Following Total Knee Replacement

Aims To determine the effects of tibial component rotation and posterior slope on kinematics following Scorpio CR navigated TKR in cadaver specimens. Methods & Results Knee kinematics were monitored using a validated IR Navigation System. Ten normal comparable cadaver specimens were mounted in a custom rig allowing assessment of kinematics under various loading conditions. The specimens then underwent Navigated TKR. The surgery was performed as per normal operating surgical protocols by an expert knee surgeon. However an augmented tibial component was implanted allowing the researchers to precisely modify its rotation and posterior slope. A pneumatic cylinder attached to the quadriceps tendon was then used to repetitively flex and extend the knee with a variety of applied loads. Kinematics were different after TKR. Increasing posterior slope resulted in increasing posterior position of the femur, particularly at maximum flexion. Posterior slope also resulted in a deviation of the neutral path of motion and alteration of the normal envelope of laxity. Tibial component malrotations over 5 degrees resulted in deviations of the neutral path of motion without affecting the envelope of laxity. Combined malrotations over 10 degrees with posterior slopes over 6 degrees resulted in prosthetic subluxation under certain loading conditions. Discussion Knee kinematics are different after TKR. Increasing internal and external malrotation as well as the addition of posterior slope resulted in deviations of TKR kinematics through alteration of the neutral path of movement and or the envelope of laxity. Combined misalignments of slope and rotation resulted in the greatest deviations from normal kinematics, and in some cases, prosthetic subluxation. Incompatibilities of alignment may result in increased ligament tension and component articulation dysfunction that may contribute to premature wear and loosening. Surgeons should be aware of this when considering the addition of posterior slope or assessing tibial component positioning in TKR

IoT protocols, architectures, and applications

The proliferation of embedded systems, wireless technologies, and Internet protocols have made it possible for the Internet-of-things (IoT) to bridge the gap between the physical and the virtual world and thereby enabling monitoring and control of the physical environment by data processing systems. IoT refers to the inter-networking of everyday objects that are equipped with sensing, computing, and communication capabilities. These networks can collaborate to autonomously solve a variety of tasks. Due to the very diverse set of applications and application requirements, there is no single communication technology that is able to provide cost-effective and close to optimal performance in all scenarios. In this chapter, we report on research carried out on a selected number of IoT topics: low-power wide-area networks, in particular, LoRa and narrow-band IoT (NB-IoT); IP version 6 over IEEE 802.15.4 time-slotted channel hopping (6TiSCH); vehicular antenna design, integration, and processing; security aspects for vehicular networks; energy efficiency and harvesting for IoT systems; and software-defined networking/network functions virtualization for (SDN/NFV) IoT

Integrated out-of-hours care arrangements in England: observational study of progress towards single call access via NHS Direct and impact on the wider health system

Objectives: To assess the extent of service integration achieved within general practice cooperatives and NHS Direct sites participating in the Department of Health’s national “Exemplar Programme” for single call access to out-of-hours care via NHS Direct. To assess the impact of integrated out-of-hours care arrangements upon general practice cooperatives and the wider health system (use of emergency departments, 999 ambulance services, and minor injuries units). Design: Observational before and after study of demand, activity, and trends in the use of other health services. Setting: Thirty four English general practice cooperatives with NHS Direct partners (“exemplars”) of which four acted as “case exemplars”. Also 10 control cooperatives for comparison. Main Outcome Measures: Extent of integration achieved (defined as the proportion of hours and the proportion of general practice patients covered by integrated arrangements), patterns of general practice cooperative demand and activity and trends in use of the wider health system in the first year. Results: Of 31 distinct exemplars 21 (68%) integrated all out-of-hours call management by March 2004. Nine (29%) established single call access for all patients. In the only case exemplar where direct comparison was possible, cooperative nurse telephone triage before integration completed a higher proportion of calls with telephone advice than did NHS Direct afterwards (39% v 30%; p<0.0001). The proportion of calls completed by NHS Direct telephone advice at other sites was lower. There is evidence for transfer of demand from case exemplars to 999 ambulance services. A downturn in overall demand for care seen in two case exemplars was also seen in control sites. Conclusion: The new model of out-of-hours care was implemented in a variety of settings across England by new partnerships between general practice cooperatives and NHS Direct. Single call access was not widely implemented and most patients needed to make at least two telephone calls to contact the service. In the first year, integration may have produced some reduction in total demand, but this may have been accompanied by shifts from one part of the local health system to another. NHS Direct demonstrated capability in handling calls but may not currently have sufficient capacity to support national implementation

The Employer-based Health-Insurance System (EBI) Is At Risk: What We Must Do About It

This report presents the first two parts of CED's research and covers the scope of the crisis in health care and the options for fixing the system. A third part offering CED's recommendations, Quality, Affordable Health Care for All: Moving Beyond the Employer-Based Health-Insurance System, was released in October 2007

Biomechanics of Contemporary Implants and Prosthesis: Modeling, Experiments, and Clinical Application

Modern medicine is now more oriented towards patient-based treatments. Taking into account individual biological features allows for increasing the quality of the healing process. Opportunities for modern hardware and software allow not only the complex behavior of implants and prostheses to be simulated, but also take into account any peculiarities of the patient. Moreover, the development of additive manufacturing expands the opportunities for materials. Technical limits for composite materials, biomaterials, and metamaterials are decreasing. On the other hand, there is a need for more detailed analyses of biomechanics research. A deeper understanding of the technological processes of implants, and the mechanobiological interactions of implants and organisms will potentially allow us to raise the level of medical treatment. Modern trends of the biomechanics of contemporary implants and prostheses, including experimental and mathematical modeling and clinical application, are discussed in this book

EFFECTS OF INCREASED Q-FACTOR ON KNEE BIOMECHANICS DURING CYCLING

Q-Factor (QF), the inter-pedal width, in cycling is the analog to step-width in gait. Increased step-width has been shown to reduce peak knee abduction moment (KabM), however no studies have examined the frontal plane biomechanics with increased QF in cycling. Purpose: The purpose of this study was to investigate the effects of increased QF on frontal plane knee biomechanics during cycling in healthy participants. Method: Sixteen healthy participants (age: 22.4 ± 2.6 yr, BMI: 22.78 ± 1.43 kg/m2) participated in this study. A motion analysis system and customized instrumented pedals were used to collect five trials of three-dimensional kinematic (240 Hz) and pedal reaction force (PRF, 1200 Hz) data in twelve testing conditions, four QF conditions of Q150 (150 mm), Q192 (192 mm), Q234 (342 mm), Q276 (276 mm), and three workrate conditions of 80 W, 120 W, and 160 W. A 3 × 4 (QF × workrate) repeated measures ANOVA was performed to analyze differences between conditions (p \u3c 0.05). Results: Increased QF increased peak KAbM 47, 56, and 56% from Q150 to Q276 at each workrate respectively. Mediolateral PRF increased 46, 57, and 57% from Q150 to Q276 at each workrate. Frontal plane knee angle and range of motion (ROM) decreased with increased QF. No changes were observed for peak vertical PRF, knee extension moment, sagittal plane peak knee joint angles or ROM. Conclusions: These results indicate increasing QF will increase peak KAbM. Future studies should examine the effects of increased QF on obese and knee osteoarthritis patients

Influence of Mechanical Conditions Driving Clinical Performance of Medical Device Constructs and Systems: A Dual-Study Approach in Human and Veterinary Fields for Optimization of the Clinical Outcome

The work performed focused on the investigation of human and veterinary orthopedic devices. The work was accomplished in two parts and focused on different device aspects, with emphasis on biomechanical implications. Part I covers the design, development, and implementation of a novel joint motion replicator and was divided into two sections: (a) Joint Motion Replicator design and development, and (b) Joint Motion Replicator implementation in a toggle rod construct ex vivo study application. The replicator provides a dual-axis, closed-loop, stepper-controlled mechanical testing environment capable of reproducing physiologically relevant loading conditions and dynamic processes. Additionally, the ex vivo study compared biomechanical performance of three toggle rod fixation systems using cyclical testing protocols simulating flexion/extension and abduction/adduction. Part II of this work covers human implantable orthopedic devices, specifically devices used to treat fifth metatarsal base fractures located at the metaphyseal-diaphyseal watershed junction (Jones fractures). This project compares the biomechanical performance of a well-known intramedullary screw construct with a plantar-lateral plating construct applied to replicated Jones fractures in paired cadaver foot specimens