We are one of very few research programs in the world working toward translation of “smart” orthopaedic implants – implants which have diagnostic capabilities in addition to their therapeutic function. To facilitate use of smart implants in daily clinical practice, we have developed and implemented a award winning and patented sensor system that is fundamentally different from previous systems. The sensor is simple. There is no battery. There is no telemetry. There are no integrated circuits and there are no electrical connections between any components. Because the system is so simple, it is also inexpensive. It is also robust because there are no electrical connections to fail. Importantly, because of its small size, there is little or no modification required of the host implant.

The sensors are passive inductor-capacitor (LC) resonators with only three components. The properties and configuration of these components dictate the function and performance of the sensor. Sensor components are fabricated using either PCB fabrication techniques or various microfabrication techniques, and our most basic design costs approximately $0.01 to manufacture. Sensors are interrogated by an external reader which is comprised of an antenna and signal conditioner using a method which allows us to read multiple sensors simultaneously. The sensors are a platform technology and can be used to measure physical stimuli including force, pressure, temperature, and pH as well as specific chemical and biological analytes.

See image of sensors and image of sensor calibration.

View our video demonstrating an early prototype smart knee enabled by our sensor technology.

This research is being led by Ben Liddle. We collaborate with Nate Cady, Ph.D. at SUNY Polytechnic Institute and Reena Dahle, Ph.D. at SUNY New Paltz.

Smart Fracture Plate:

Non-union occurs in 5% of fractures and up to 41% of distal femoral fractures treated with plate osteosynthesis. These non-unions result in substantial morbidity and necessitate return to the operating room. Currently, the diagnosis of non-union is based on qualitative clinical examination and radiographic assessment of callus. These techniques are subjective and frequently ambiguous.

Measurement of callus stiffness provides an objective quantitative assessment of the progress of fracture healing. An osteosynthesis plate is loaded in parallel with the fracture, thus measuring forces in the plate can be used as an indication of callus stiffness. As callus stiffness increases, it is able to bear load proportional to its stiffness and forces through the plate decrease. In this way, measuring forces through the plate can serve as an objective indicator of fracture healing. While these biomechanical concepts are well accepted, to date, these techniques have only been used as research tools and only with external fixation.

We have developed a novel technique to measure forces through fracture plates with no modification to the plate using our wireless sensors and “force concentrators”. The patent-pending force concentrator acts as a mechanical amplifier and converts axial load applied to the plate into transverse forces measured by the sensors.

Please view our video showing a prototype smart fracture plate and an image of our latest design.

This project is led by Madelyn Stout and Connor Hanggi. We collaborate with Michael Archdeacon, MS, MD at the University of Cincinnati, David Forsh, MD at Mt. Sinai School of Medicine, and Keegan Cole, MD at the Albany Medical College.

Smart Intrameduallary Rod:

The tibia is the most common long bone to be fractured. Diaphyseal fractures of the tibia are often fixed surgically with intramedullary rods. Healing typically takes 4 to 6 months and the progression of healing can be ambiguous based on clinical exam and plain radiographs. Yet, the early diagnosis of non-union or protracted union provides impetus for additional interventions such as bone stimulators, dynamization of the rod, or exchange rodding.

Like a fracture plate, an IM rod is loaded in parallel with the fracture, thus measuring forces in the rod can be used as an indication of callus stiffness and progression of healing. In this way, measuring forces through the rod can serve as an objective indicator of fracture healing.

We are continuing development of a novel technique to measure forces through IM rods using our wireless sensors and “force concentrators”. The patent-pending force concentrator acts as a mechanical amplifier and converts axial load applied to the plate into transverse forces measured by the sensors.

This project is led by Ben Liddle.

Wireless Injectible Intracompartmental Pressure Monitor:

Acute compartment syndrome (ACS) is a true surgical emergency and the sequelae of a missed or delayed diagnosis is devastating to the patient. ACS occurs following traumatic extremity injury which can result in irreversible tissue necrosis if untreated. Currently, diagnosis is based on clinical exam and intra-compartmental pressure measurements via needle manometer. Clinical exam can be unreliable in obtunded patients and manometer techniques are largely inconsistent.

We have recently adapted our novel wireless sensor technology to provide continuous monitoring of intra-compartmental pressures to measure intra-compartmental pressures. The form factor, size, range, and sensitivity of the sensors is customizable, and ongoing work is focused on adapting the sensors to deploy through a large bore needle. The application of our sensor technology has the potential to provide accurate, continuous monitoring of intra-compartmental pressures, allowing the early detection of impending ACS.

See image of a 1st generation and 2nd generation prototype pressure sensor and prototype ceramic housing for monitoring intracompartmental pressure.

This project is led by Ben Liddle and Kate Ronin. We collaborate with Michael Archdeacon, MS, MD at the University of Cincinnati, David Forsh, MD at Mt. Sinai School of Medicine.

Optimizing Spinal Fusion:

There are more than 400,000 spinal fusion procedures performed each year the United States alone. A successful outcome following spinal fusion surgery requires the right combination of biological and biomechanical environment to promote bridging bone formation. The mechanical properties of the implants dictate the biomechanical environment and can bias the environment toward stress-shielding or toward load-sharing. Only by directly measuring the in vivo biomechanics of the cervical spine can implant design be optimized to facilitate optimal interbody loading, load-sharing, and the progression of fusion.

We have developed a “smart” interbody implant to measure real time in vivo forces in the cervical spine. In this ongoing work, we have shown the magnitude of interbody forces in the cervical spine in vivo is dynamic and correlates to activity, posture of the head and neck, and to implant stiffness. More compliant implants result in more consistent load-sharing and stimulate better bone formation and maturation.

We are continuing this research by developing an interbody implant that will measure interbody forces and facilitate spine fusion in vivo. We will measure interbody forces while manipulating the biomechanical environment to establish correlations between implant properties, the mechanism of bone healing (endochondral or intramembranous), the rate of bone formation, and the rate and quality of fusion. We will control the biomechanical environment by modulating implant stiffness, rehabilitation regimen, and external bracing.

Please view our video of a prototype smart interbody implant.

The project is led by Rebecca Levy and Sierra Blondeau. We collaborate with Darryl DiRisio, MD at the Albany Medical College and Joseph C. Glennon VMD.

Anterior Knee Pain Following Knee Arthroplasty:

Osteoarthritis (OA) is a leading cause of chronic disability and pain. For patients who fail conservative care, the gold standard treatment for knee OA is a total knee arthroplasty (TKA). Although TKA is one of the most common surgical procedures performed in the US, the incidence of anterior knee pain following TKA affects 8-53% of TKA patients.

There are a number of factors that may alter the biomechanics of the patellofemoral joint leading to increased forces and anterior knee pain. The measurement of patellofemoral forces could contribute significantly to the understanding of patellofemoral joint mechanics and the etiology of anterior knee pain.

The purpose of this research was to utilize our wireless force sensing technology to develop the first “smart” patella to measure patellofemoral forces and correlate them to parameters such as implant size and positioning.

Sensors were integrated onto an off-the-shelf patellar implant so that they were loaded in series with the implant. Different thickness implants were placed and the position of the implant varied (patella-alta vs. patella-baja) and forces were measured at 0°, 45°, 75°, and 90°.

Data indicate that both the magnitude and distribution of forces at the patellofemoral joint is highly sensitive to changes in implant thickness and position and that changes of as little as 1 mm can significantly affect forces. These effects were most pronounced at angles of high flexion.

See image of our smart patellar implant.

On this knee biomechanics work, we collaborate with Jared Roberts, MD at the Albany Medical College, and Cobus Muller, Ph.D. at Stellenbosch University.

Biomechanics of Spinal Degeneration:

Repeated exposure to high magnitude forces in the spine is associated with symptomatic degeneration of the intervertebral disc. Minimizing exposure to high magnitude forces in the workplace is important for reducing work-related injuries and minimizing lost work time.

Forces in the intervertebral disc are highly dynamic and correlate to activity, posture, and external loads. The spine moves in six degrees of freedom and loading is a complex combination of forces and moments about multiple axes simultaneously. Understanding the relationship between extrinsic factors and forces in the disc may provide valuable insight into the biomechanics of degeneration.

We are currently developing a multi-axial “smart” interbody implant-load cell that will measure axial compressive forces, anterior/posterior shear forces, and lateral shear forces in the disc simultaneously. Correlating multi-axial force to spine motion and activity is significant because shear forces are thought to initiate or exacerbate spinal degeneration.

This research will provide a better understanding of the role of mechanics in the disease process, of how to establish safer workplace practices, and for the design and development of the next generation of spinal implants.

See image of a prototype smart interbody cage for in vivo applications.

The project is led by Rebecca Levy and Sierra Blondeau. We collaborate with Darryl DiRisio, MD at the Albany Medical College.

Enhanced Small Molecule Transport as a Strategy for Intervertebral Disc Therapy:

Low back and neck pain are the leading cause of chronic disability world-wide. Most commonly, back and neck pain are associated with degeneration of the intervertebral disc. In the early stages of degeneration, the disc can upregulate biosynthesis to restore matrix homeostasis, but with this increased metabolic activity, there is also an increase in production of harmful metabolic byproducts. Accumulation of these byproducts can lead to a dangerous decrease in pH, an increase in cell apoptosis, and further degeneration.

Importantly, the disc is avascular and relies on passive diffusion for uptake of critical nutrients and clearance of harmful byproducts. Thus, the disc’s ability to sustain an increase in metabolic activity is constrained largely by its limited uptake of nutrients and clearance of byproducts. In this way, the disc’s regenerative potential is very much limited by small molecule transport.

In this award winning research, we have recently shown that forced convection from cyclic axial loading can be used to enhance transport to/from the disc. In this ongoing work, we are optimizing the loading parameters to most effectively enhance transport at all stages of degeneration to enhance uptake, clearance, and biosynthesis in the disc and we are currently conducting studies to determine the long-term effect of cyclic axial loading on the health and regenerative potential of degenerated intervertebral discs.

Ultimately, the clinical translation of this work is to develop a regimen of therapeutic cyclic weight-bearing exercises which can enhance uptake and clearance of critical small molecules in the intervertebral disc via forced convection through all stages of degeneration.

See MRI images and data related to this research.

This project is being led by Liz Capogna, Emma Brown, Evan Walrath, and Will Furst. We collaborate with Gwen Sowa, MD, Ph.D. at the University of Pittsburgh, Jeffrey Lotz, Ph.D. at the University of California at San Francisco, Darry DiRisio, MD at the Albany Medical College, and the staff at the Stratton VA Medical Center.

Dynamic Seating Interface to Prevent Pressure Ulcer Formation:

For the more than 70 million long term wheelchair users worldwide, pressure ulcer formation is a common complication. There are more than 7 million new pressure ulcers each year as a result of high localized pressure for prolonged periods. Pressure ulcers are painful for the individual and treatment is expensive for the healthcare system.

Prevention is key to mitigating the effects of pressure ulcers. Current prevention strategies rely on custom contouring of seat cushions to reduce magnitude of pressure at the seat-skin interface. However, this is not effective in many consumers because of the inability to reduce pressure to an acceptable range.

We have engaged in the development and testing of a novel dynamic seating interface. Our ongoing research has shown that dynamic support arrays comprised of interrupted shapes can be used to affect temporal modulation of locations of high pressure. By modulating between high and low pressure, tissue perfusion is preserved and pressure ulcer formation is prevented.

Current research efforts are focused on optimization of the geometry of the patent pending shape array, validation of the dynamic mechanism, and validation of restoration of tissue perfusion.

See images of the pressure sore prevention array here.

This project is being led by Liz Capogna and Ben Liddle. We collaborate with the staff and consumers of the Center for Disability Services.

Oral Hygiene for Individuals With Disabilities:

More than 12 million people in US need assistance for activities of daily living. For consumers with cognitive or physical disabilities, oral hygiene remains a challenge. This is significant because poor oral hygiene increases likelihood of poor overall health.

Many consumers with disabilities are dependent on caregivers for oral hygiene. Often, consumers consider oral hygiene an unpleasant experience and are resistive to the efforts of caregivers to assist them. Current solutions are limited to manual toothbrushes and oral swabs, restricting a caregiver’s performance of daily oral care procedures.

In ongoing research, we have developed a patent pending novel oral hygiene system which includes a cleaning component specifically designed for a caregiver to provide efficient oral hygiene to a consumer.

See image of the toothbrush design and image of modular prototype for testing.

This project is being led by Liz Capogna and Nicole Zimmer. We collaborate with the staff and consumers of the Center for Disability Services.

Bathing Individuals With Disabilities:

Bathing of a disabled individual by a caregiver remains a significant challenge because of increased risk of slip and fall or other injury for both the caregiver and consumer. Bathing seats are the most common solution in home care environments. However, there are significant limitations which include (i) the likelihood of caregivers getting wet, (ii) the need to reposition the consumer to clean all areas of the body, and (iii) the incidence of strains and falls of caregivers and falls of consumers.

In ongoing research, we have developed a novel bathing system which eliminates the limitations of current caregiver-based bathing systems. We are testing and optimizing the design of our novel solution to maximize efficacy and safety.

On this caregiver-based bathing work, we collaborate with the staff and consumers of the Center for Disability Services.

MOVE Program Outcomes Assessment:

The Mobility Opportunities Via Education/Experience (MOVE) program is a well-established activity-based therapy program for enhancing physical function of individuals with disabilities. The program is based on sequences of activities each of which builds on the previous tier of activities. Therapists and consumers purport several benefits of the program which include better cardiac health, pulmonary health, gastrointestinal health, and reduction in muscle contractures, among others. While the benefits of the program are universally accepted by caregivers and consumers, objective quantitative data demonstrating the health benefits of the program are lacking.

In ongoing research, we are developing outcomes assessment tools for demonstrating the value of the MOVE program to overall health of individuals who participate in the program.

This project is being led by Madelyn Stout. We collaborate with the staff and consumers of the Center for Disability Services.