Total hip replacement is a widespread medical procedure, with over 300,000 surgeries performed each year in the US alone. The vast majority of total hip replacements utilize press fit fixation, where the implant cup is physically impacted into the patient’s acetabular cavity. Successful seating of the implant requires a delicate balance between inserting the implant deep enough to obtain sufficient primary stability, while avoiding fracture of bone, which causes pain, complications during recovery, and revision surgery. To improve patient outcomes, this surgical field needs assistive technologies that can measure the forces applied during press fit fixation, and provide real-time feedback to guide how much force to apply, and when to stop applying additional forces. The development of such technology, however, requires a greater understanding of the forces experienced at the implant-acetabular cup interface, and the resulting cup insertion and implant stability. Here, we present a preliminary study of acetabular cup insertion into bone proxy samples. We find that as the magnitude of force on the acetabular cup increases, the cup displacement and axial extraction force increase linearly and then plateau. For repeated impacts of a given force, cup insertion and force experienced in bone increase correspondingly and reach a plateaued value over certain number of impacts, which represents rate of insertion. These finding suggest the plausibility of a feedback mechanism that utilizes measured force patterns in bone, implant/bone interface, and impaction tool in relation to rate of insertion to infer optimal primary implant stability in arthroplasty.

Trainees in orthopedic surgery are required to receive dedicated laboratory-based surgical skills training in their first year of residency. Simulators are often used in this training. Our group previously developed a hip fracture wire navigation simulator to train and assess skill in placing a K-wire within a femur bone surrogate using synthetic fluoroscopic images to aid in navigation. In this paper, we describe design considerations and challenges in modifying the existing simulator to enable the training of multi-wire pinning of a pediatric supracondylar humerus fracture. The design involves changing the bone of interest from the adult femur to the pediatric humerus, while using the same platform technology. Considerations include ease of use, minimizing motion of the fixed bone, and minimizing materials used. The robustness of the bone mounting was tested by running an experiment using 3D scans and surface deviation analysis to test repeatability of bone placement and its resistance to rotational motion after being placed in the fixture. After the new design was shown to hold the bone rigidly, a pilot study of the new simulator was conducted to confirm that the surgeons and residents consider the simulator experience as being a valid representation of the actual surgical skill.

Radiopaque scales have numerous uses in the field of surgery, especially orthopaedic surgery. Scales of this nature can be used to guide surgeons by taking intra-operative measurements, pinpoint insertion points on bones and detect locations of deformations and tumours inside the body. Despite this, these scales are not used widely enough because of its high cost and that there are no widely acceptable ways of developing them from off the shelf materials. This paper details the method of inventing a novel low-cost radiopaque scale using off the shelf materials such as Barium Sulfate and Iodinated Contrast Agent (ICA). The radiopaque scale was manufactured using Perspex ® and was filled with the contrast agents. The scales were then scanned using low-dose X-ray machines. The scale filled with Barium was found to be provide a better contrast image suggesting that the Barium to be a better high-contrast agent when compared to iodine and is recommended for use.

Open Reduction and Internal Fixation (ORIF) of scapula fractures have increased in numbers recently. This is due to better functional outcomes achieved post-ORIF than non-operative management techniques. In South Africa, there is only one available supplier for anatomical contoured scapula plates used in the ORIF. This study examines the fit of these plates on the bony topology of fifty healthy scapula. It was observed that the short medial body plate performed the best in adhering to the bone topology followed by the short acromion plate. The glenoid plate and the long acromion and body plates were not adequately designed to fit their intended regions on the scapula. In conclusion, this study highlights the drawbacks in design of current commercial plates available for ORIF of scapula. Further studies are needed in order to evaluate the quantitative-fit performance of these plates on fracture scapula surfaces.

Legg-Calvé-Perthes disease (LCPD) is a painful pediatric hip condition caused by an idiopathic disruption of blood flow to the femoral head. The bone subsequently becomes necrotic and fragile. This can result in significant femoral head deformity, leading to pain and early degeneration of the hip. Severity of avascular involvement of the femoral head correlates with long-term outcomes, including hip arthritis and replacement. Preclinical models present extreme cases of the disease and do not represent the spectrum of LCPD seen clinically. A virtual model was developed to explore advancing the preclinical model through new methods of visualizing the data. Overall, three opportunities to advance the preclinical model and our understanding of LCPD are presented.

Prosthetic sockets are static interfaces for dynamic residual limbs. As the user’s activity level increases, the volume of the residual limb can decrease by up to 11% and increase by as much as 7% after activity. Currently, volume fluctuation is addressed by adding/removing prosthetic socks to change the profile of the residual limb. However, this is impractical and time consuming. These painful/functional issues demand a prosthetic socket with an adjustable interface that can adapt to the user’s needs. This paper presents a prototype design for a dynamic soft robotic interface which addresses this need. The actuators are adjustable depending on the user’s activity level, and their structure provides targeted compression to the soft tissue which helps to limit movement of the bone relative to the socket. Testing of the prototype demonstrated promising potential for the design with further refinement. Work on embedded sensing and intelligent feedback control should be continued in future research in order to create a viable consumer product which can improve a lower limb amputee’s quality of life.

Cartilage plays an important role in reducing mechanical stress and assist with smooth limb movement. Osteoarthritis is the degeneration of articular cartilage and bone. This osteochondral region is difficult to heal because of its dissimilar healing capability, so osteochondral transplantation is the most common method to resolve this issue. Post-traumatic osteoarthritis develops after a joint injury and can damage the cartilage and accelerate its wear and tear. Mosaicplasty is the most widely used method involving transplantation of small cylindrical bone cartilage plugs to fill up the affected region. The success of harvesting a larger and complex shaped graft to replace the damaged osteochondral area lies in effective extraction of the cartilage-bone graft from the donor site. Currently, no method exists to perform this procedure for autologous transplantation due to the complexity involved to extract graft without damaging the donor site. In this paper, we propose a novel graft removal mechanism to harvest a personalized autologous graft of virtually any shape and size. Our method involves drilling a profile similar to the effected region on the donor site and slicing off the desired cartilage-bone graft from its root to harvest it. We developed a new graft removal mechanism capable of inserting a flexible saw parallel to the transverse plane and slice the graft parallel to the coronal plane to extract a donor graft for autografting procedures.

The American Board of Orthopaedic Surgery has mandated dedicated skills training for first-year orthopedic surgical residents. 1 Most residency programs address this requirement with training exercises with cadavers and plastic foam bones. Some programs incorporate one or more simulators in their skills training, including several sophisticated virtual reality simulators and a variety of low-tech simulators. Simulators are helpful because they can provide repeatable educational experiences and quantitative performance assessment. Unfortunately, few simulators have been developed for orthopedic trauma skills training. Even fewer simulators have been developed and validated with more advanced students, such as residents in their 3 rd or 4 th year of training, and for more complex surgeries. In contrast to the completely virtual surgical simulation using haptic feedback devices and sophisticated renderings of soft tissue deformation, our group has chosen to use physical models, real surgical instruments and position tracking in conjunction with virtual reality. 2–4 The physical models provide experience with the surgical tools, and enable more realistic hand movements and haptic cue feedback.

The goal of this study was to construct a design methodology for a prosthesis which causes less stress shielding and meets fatigue requirements. Stress shielding is the reduction in bone stresses due to the introduction of an implant. Implants may become loose when stress shielding is present because bone resorption occurs as the bone adapts to the reduced bone stresses. Topology and lattice optimization were performed using OptiStruct to design a hip prosthesis where stress shielding and prosthesis fatigue were considered. The optimized design reduced stress shielding by 50+% when compared to a conventional generic implant, and the fatigue life met the ISO standards. Additionally, manufacturability was considered in the design process and a Ti-6Al-4V prototype was printed with an EOS selective laser melting machine.

Newly developed interactive tutorials and applications which teach human anatomy are often set up as pay-to-play websites. Examples of these include the Visible Body app 1 and the 3D Organon Anatomy 2 . Though these applications can be very educational, they may be costly, thus many students and members of the education community will not access these programs because of the upfront charges. These teaching programs are also frequently anatomically limited because they utilize idealized models, like KineMan 3 , instead of renderings or imaging data sets obtained from humans (clinical or from cadavers). This characteristic may make them useful study tools, but will not best prepare future doctors, nurses, and other health professionals for true, variable patient anatomies they will encounter in their various practices. Further, such students would likely gain more by studying 3D objects of real human anatomies instead of 2D images. We have designed a strategy to bring 3D human anatomies from real cadavers to the scientific and education communities completely open source (free of charge). Our interactive application is geared toward students of all ages (grade school to medical school) or by anyone interested in learning more about human bone anatomy.

There has been an emerging interest in high intensity focused ultrasound (HIFU) for therapeutic applications. By means of its thermal or mechanical effects, HIFU is able to serve as a direct tool for tissue ablation, or an indirect moderating medium to manipulate microbubbles or perform heating (hyperthermia) for the purpose of targeted drug delivery. The development and testing of HIFU based phased arrays is favorable as their elements allow for individual phasing to steer and focus the beam. While FDA has already approved tissue ablation by HIFU for the treatment of uterine fibroids (2004) and pain from bone metastases (2012), development continues on other possible applications that are less forgiving of incomplete treatment, such as thermal necrosis of malignant masses. Ideally, each element, of such an array must have its own fully programmable electrical driving channel, which allows the control of delay, phase, and amplitude of the output from each element. To enable full control, each channel needs a waveform generator, an amplification device, and an impedance matching circuit between driver and acoustic element. Similar projects utilizing this approach to drive therapeutic arrays include a 512-channel therapy system which was built at the University of Michigan using low cost Field-Programmable Gate Arrays (FPGA) microcontroller and highly efficient MOSFET switching amplifiers [1]. However, this system lacks the ability to drive both, continuous wave (CW) and transient short duty-cycle high power pulses. This paper presents a hybrid system, which is able to perform CW and transient short duty-cycle high power excitation. In the following we will describe the design, programming, fabrication, and evaluation of this radiofrequency (RF) driver system as used in our laboratory for a 1.5 MHz center frequency, 298-element array (Imasonic SA, Besancon, France) [2], FPGA-controlled amplifier boards and matching circuitry. Advantages of our design include: 1. Inexpensive components (<$15/channel); 2. Ability to program/drive individual output channels independently; 3. Sufficient time and amplitude resolution for various acoustic pattern design; 4. Capability of hybrid switching between low power CW and short duty cycle, high instantaneous power.

The physical impairment caused by OA of a single lower extremity joint is comparable to that reported for major life-altering disorders such as end-stage kidney disease and heart failure. (Buckwalter, et al) [1] Ankle distraction arthroplasty has been shown to greatly decrease pain due to end-stage ankle arthritis. Unlike arthrodesis (fusion of the joint), distraction arthroplasty maintains the joint’s natural movement, and it is far less complicated than total joint replacement surgery. There is a considerable body of research supporting the idea that distraction of an end-stage arthritic joint (most of the work thus far has been done on ankles, although there has also been some investigation of the efficacy of the treatment for knee arthritis) for a period of weeks allows the growth of new tissue in the joint. Although this tissue is not true articular cartilage, distraction arthroplasty has been shown to significantly decrease pain and, in the majority of cases, to be a long lasting remedy for a condition that would otherwise commonly be treated with arthrodesis. [2] Devices currently available for this procedure are generally quite complicated because they are designed for a wide range of functions related to bone fixation. This versatility also tends to make those systems larger and more expensive, and their aggressively mechanical appearance makes potential joint distraction patients hesitant to select the procedure. While fracture patients may not have a choice about being treated with such devices, elective patients are instinctively resistant to their use, even when assured that the end result will most likely significantly improve in the quality of their lives.

Spondylitis is a very common back and neck ailment that is reported to account for one-third of social problems causing difficulty at work. It is caused due to the inflammation in vertebral joints. Its condition goes undetected until the symptoms, such as that of severe pain, develops. It causes stinging pain which is focused around cervical region of vertebra, the shoulders and the lumbar region of the spine. Accordingly, it is classified into three types: cervical, thoracic and lumbosacral spondylosis. This is different from spondylitis which causes pain due to inflammation. Many existing devices use electric current to bring relief from pain. Transcutaneous electrical nerve stimulation (TENS) is one of the most commonly used devices in this aspect. However, though this has been able to bring effective results to its patients, there is a whole lot of controversy in conditions it should be used to treat. Studies have shown these devices to bring relief by suppressing the signals from the brain. They are not advised for patients with pacemakers or any kind of electronically powered implantable devices. They are less effective where the skin is numb or in places where there is decreased sensation. It depends entirely on the working of the nerve beneath the surface and may cause irritation on the skin if the current is too high. Moreover, these devices need to be avoided in area where infection is present. High precaution needs to be taken when working with epilepsy patients and pregnant women; the electrical stimulation can interfere with the fetus development. With such a wide range of drawbacks, there is a need for a mechanical solution which can redress these problems and provide an effective and ergonomic solution. Along with overcoming the present barriers, research has been done to demonstrate the positive effects of vibration in increase of bone density, increase of muscle mass, increase of blood circulation, reduced back pain, reduced joint pain and boost in metabolism. The given paper discusses a device wherein vibrational motors have been incorporated, under the control of a microcontroller, to generate the requisite g-force needed for the purpose of pain alleviation and increase of bone density.

Bicoronal approach is commonly used to repair intracranial trauma [1,2]. However, this approach requires long operation time and may lead to a long-lasting visible scar. In addition, patients stay in the hospital for several days. Therefore the demand for minimally invasive operation technique is increasing for reduction of facial bone fracture. Yoo et al. reported closed reduction technique using a thread-tapper device [3]. This method uses the tapper as a tool to make a thread of screw tightening a bolt. The method needs small incision. By pulling out the tapper, the depressed bone segment can be easily recovered. Another method is to use a hook. This device can be inserted into a small hole in the skin [4]. The screw is used for reducing multi-fragmented segments of anterior wall of frontal sinus. Two or more small screws are inserted into fragmented segments, and then pulled out simultaneously [5]. These closed reduction surgical devices have advantages of reducing operation time and scars, and quickening recovery. However, they can be only applied if the tapper or screw can be inserted into the depressed bone segments. In this technical brief, we propose a spiral tool and pulling mechanism for closed reduction facial bone fracture. Using prototypes, we present that the suggested surgical tool and mechanism are good alternatives for reduction of facial bone.

Due to the anatomical and physiological similarities to humans that include similar heart size, flow rate, skin, liver enzymes and bone healing, porcine models as a powerful investigational platform have been widely used in research areas such as diabetes, obesity and islet transplantation [1]. The advantages of relative low cost, ease in handling and comparatively short period of breeding time may make swine provide a promising solution to the shortage of human donors and difficulty in isolating purified islets from adult human in future. Porcine cytokines play a significant role in innate immunity, apoptosis, angiogenesis, cell growth and differentiation. They are involved in cellular responses, maintenance of homeostasis, and disease states such as inflammatory disease, cardiovascular disease, and cancer. Thus, the technologies to analyze the expression of cytokines are developed rapidly and are still hot topics. The traditional approach for cytokine detection and quantification is the use of an enzyme-linked immunosorbent assay (ELISA). However, its inability to do multiplex test calls for more robust detection system. Biochip-based assay for the detection of biological agents using giant magnetoresistive (GMR) sensors and magnetic nanoparticles have emerged recently [2, 3]. It is proved that the nanomagnetic biosensor technology has advantages of low cost, high sensitivity, multiplexity, and real-time signal readout. The integration of GMR biosensor and use of weak magnetic fields allow to eventually realize point-of-care and portability. In addition, interferon gamma (IFNγ) is one of the most important porcine cytokines, and is associated with a number of autoinflammatory and autoimmune diseases. In this work, IFNγ is selected as a model target for the detection of porcine cytokine using nanomagnetic GMR biosensor.

Lower limb length discrepancy (LLD), defined by unequal length of paired lower limbs, contributes to lower back pain, osteoarthritis of the hip, and stress fractures [1–3]. The Center for Disease Control and Prevention estimated that there were approximately 700 children born with LLD each year in US [4]. Patients may receive distraction osteogenesis treatment, in which an osteotomy is performed on the shorter limb, and mechanical force is applied to gradually distract the two halves of the bone during the healing process. This stretches the bone callus during healing to achieve desired limb length upon callus consolidation [5]. The current correction devices are external fixators that leave unsightly scars and are prone to infection [6]. While recently developed intramedullary devices address many of the persistent issues with external lengthening devices, size limitations and potential damage to the bone growth plates make them impractical for use in children [7, 8]. The proposed research addresses an unmet need by developing a novel implantable extramedullary device for LLD correction that is targeted for pediatric use. The device will be implantable, submuscular, and fixed to the outside surface of the bone (extramedullary), thus allowing for use in children without concern for injury to the growth plates. The device’s function will be similar to an external fixator; however, it will not require exposed hardware, which increases risk of infection, or muscle penetration from the pins, which causes pain. Additionally, the device incorporates real-time control of the distraction rate, reducing the risk of complications arising from fixed rate distraction such as premature consolidation and non-union of the callus. [9–11]. The investigators of this study have previously designed and constructed a distraction mechanism prototype and test frame [10]. The current study aims to validate the real-time controller of the prototype.

Seligson [1] describes how Hoffmann and Jaquet, a medical doctor and an engineer, respectively, developed the original Hoffmann fixator as a tool to stabilize human fractures with minimal invasiveness. Whether being utilized in mass trauma injury situations such as the 2010 Haitian earthquake, within our emerging geriatric population, or in veterinary applications, external fixation is widely used [1–4]. In this investigation, a rod-to-wire coupling, shown in Figure 1, and hereafter referred to as the R2W clamp, has been designed and validation tested for Stryker Orthopaedic’s Hoffmann II (HII) External Fixation System. As the name implies, this clamp has the purpose of connecting 8mm rods to 1.5mm or 2mm Kirschner (k-) wires or olive wires to stabilize bony fragments in the lower extremity, thus expediting healing in a trauma case. This paper summarizes the results of the validation tests conducted on prototype clamps. This clamp effectively allows placement of a wire to further stabilize a frame [3] by allowing wire placement without the addition of an intermediate ring, as shown in Figure 2. The wire could be added to any configuration with two parallel rods extending in plane with the bone. As shown in Figure 3, the R2W clamp can be positioned “outboard” with the rod between it and the bone, or “inboard” between the rod and the bone, allowing the surgeon geometric flexibility. The use of two k-wires is recommended to stabilize each bone fragment [5]. One of the goals of the validation testing was to determine the effectiveness and functional safety of the clamp as related to surgically applied k-wire tensions of either 50 kg or 100 kg. Since it is feasible that surgeons may tighten, loosen, then retighten the clamp while positioning it during surgery, the effects of clamp retightenings on the performance of the R2W clamp were also evaluated [4].

Over the past decade, natural orifice transluminal endoscopic surgery (NOTES) has developed out of a merger of endoscopy and surgery [1]. NOTES offers the advantages of avoiding external incisions and scars, reducing pain, and shortening recovery time by using natural body orifices as the primary portal of entry for surgeries [2]. The NOTES platform consists of a flexible, hollow body — enabling travel in the interior of the human body — and the distal end (head), the mechanical structure of which is based off of the snake bone. After the distal end passes through a natural orifice, through a transluminal opening of the stomach, vagina, bladder, or colon, and reaches the target working place in the peritoneal cavity, several therapeutic and imaging tools can be passed through the hollow conduit of the NOTES’ body for surgeries [3]. The traditional snake bone design presents two major problems. First, the movement is constrained to two bending degrees-of-freedom (DOF). A need to reorient the tool then often requires the entire body to be rotated by the physician, an unwieldly manipulation that both hinders convenience and results in imprecise control. Second, the traditional fabrication process is tedious and therefore lends to higher manufacturing costs; the bending joints must be first individually machined then assembled together piece-by-piece using rotation pins. We propose a novel design for the snake bone that introduces an additional DOF via rotation and is simple and cost-effective to machine. The revised snake bone design features rotation segments controlled by wires that a physician can readily manipulate for increased control and convenience. Further, because surgical tools that pass through the NOTES body conduit are also installed on snake bone structures, the introduction of rotation to the snake bone design increases each tool’s mobility and manipulation. This advance therefore presents the potential to decrease both the number of required tools and the overall diameter of the NOTES body. Finally, the body is machined as a single element and therefore minimizes the work of assembly.

Impaired mobility is ranked as one of the most important factors that have both physical and mental impacts on patients’ life [1]. The impacts are especially serious for the rapidly expanding elderly population in the United States, which is expected to reach 71 million, approximately 20% of the total population, by 2030 [2]. Existing assistive tools, such as cane and walker/rollator, are helpful for such mobility-challenged individuals by providing additional support in walking. However, such tools also disrupt the users’ walking rhythm and increase their metabolic energy consumption. Wheelchairs, especially powered wheelchairs, are also used extensively among this population. Although wheelchairs are effective in transporting patients, they largely preclude the users’ lower limb muscle activities and bone load-carrying, and accelerate the musculoskeletal degeneration of the user’s lower limb [3]. To address the issues with existing assistive tools, the authors developed a new motorized robotic walker for mobility-challenged users. With the objective of assisting the users’ ambulation in a safe and convenient way, the robotic walker features two independently controlled wheels for the maneuverability of the robot, and two parallel bars for the user support in walking. Unlike similar robotic walkers in prior works (e.g. [4]), no wearable sensors are required for the user. Instead, a 3D computer vision system is used to measure the relative position of the user versus the robot, and the control commands are generated accordingly. The details of the robot design and control are presented in subsequent section.

Orthopaedic resident training has been, and continues to be, in a state of flux. Initially, there were limits placed on the number of hours a resident could work in a week [1]. Later, residency programs were required to provide laboratory-based training in basic surgical skill for first year residents [2]. Now there is a push towards a competency-based training program that graduates residents who demonstrate their acquisition of adequate surgical skills [3]. With each of these shifts in the training model, programs and institutions have looked increasingly to simulation-based training to ease the way. Simulation offers opportunities to train surgeons quickly, provide essential feedback to foster improvement, and assess skill acquisition. With the broad swath of requirements to satisfy in orthopaedic surgical skills training, a simulation platform must support an array of training capabilities for resident practice and performance assessment. Wire navigation is a central skill in orthopaedics that has a broad variety of applications. In this task, surgeons must use 2D intra-operative fluoroscopic images to visualize the 3D anatomy of a patient and place a wire along a specified path through bone. In some situations, placing the wire is the final task; in others the wire serves as a guide for subsequently placed cannulated implants. Regardless of the situation, the placement of the wire in the bone directly influences the surgical result for the patient. We previously presented the design of a wire navigation surgical simulator dedicated specifically to hip wire navigation [4]. Our experience with the dozens of surgeons and residents who have used the simulator suggest that they find the general skill of guiding a wire to be relatively abstract. They are more drawn to practicing specific surgeries rather than the general skill. To address this need, we have modified the simulator to present new surgical procedures, while still exercising the underlying skill of wire navigation. We also learned that the task of directing the fluoroscope in order to acquire appropriate view angles for making surgical decisions is integral to surgical wire navigation, so we extended the simulator to include this important aspect of surgical skill.