Founded in 1958, the AO foundation is a medically guided, not-for-profit organisation led by an international group of surgeons specialised in the treatment of trauma and disorders of the musculoskeletal system. Today, the AO has a global network of over 200,000 health care professionals. Each year it offers over 830 educational events around the world, which are supported by nearly 9,000 faculty and are attended by over 58,000 participants. It has 20,000 surgeon members working in the fields of trauma, spine, craniomaxillofacial (CMF), veterinary, and reconstructive surgery.

The Mission of the AO foundation is promoting excellence in patient care and outcomes in trauma and musculoskeletal disorders. The focus of the AO clinical divisions, clinical unit, and Institutes, is on producing new concepts for improved fracture care, delivering evidence-based decision making, guaranteeing rigorous concept and product approval as well as timely and comprehensive dissemination of knowledge and expertise. The AO is made up from four clinical divisions (AOTrauma, AOSpine, AOCMF, AOVET), one clinical unit (AORecon), and four institutes the AO Research Institute Davos (ARI), AO Education Institute, AO Clinical Investigation & Documentation and AO Technical Commission (AOTK).

AO Research Institute Davos (ARI) is both the academic arm and the translational arm of the AO foundation. In its work to further the AO foundations mission (promoting excellence in patient care and outcomes in trauma and musculoskeletal disorders), ARIs purpose is to advance patient care through innovative orthopaedic research and development.

The goals of ARI include: Contribute high quality applied preclinical research and development (exploratory and translational) focused towards clinical applications/solutions; investigate and improve the performance of surgical procedures, devices and substances; foster a close relationship with the AO medical community, academic societies, and universities; and provide research environment / research mentorship / research support for AO clinicians.

Our Bone Regeneration focus area looks at bone healing in response to fracture involving a complex sequence of dynamic events, directed by numerous different cell types and growth factors. A critical factor for bone repair is the maintenance, or effective restoration, of an adequate blood supply, which is necessary to provide the damaged tissue with oxygen, nutrients and growth factors, as well as immune cells and mesenchymal stem cells required to repair the damage and induce new bone formation. Although bone generally has a high regenerative capacity, in some cases this inherent bone healing is compromised, which results in delaying healing or non-union of the bone fracture with increased health care costs and reduced quality of life issues for affected patients.

While a variety of risk factors have been identified that predispose a patient to an increased risk of developing delayed bone healing or non-union, it is currently not possible to identify specific at-risk patients at an early stage. Using in vitro, in vivo and microfluidic technologies, the aim of the Bone Regeneration Focus Area is to gain a greater understanding of the cellular interactions and mediators, including immunoregulation, underlying such impaired healing responses. By determining how cells such as immune cells, mesenchymal stem cells and endothelial cells normally interact during the repair process, and how this process is altered during impaired healing, we can then identify key mediators of the healing process. Our goal is to use tissue engineering and regenerative medicine approaches to promote bone healing, aimed at restoring bone integrity and its effective biomechanical properties.

In terms of this focus area, we aim at investigating the potential mechanisms leading to intervertebral disc (IVD) damage and evaluating novel biological treatment methods for IVD repair and regeneration. Acute and chronic damage to the IVD are major causes of low back pain. However, the factors that contribute to the loss of function of the IVD and the underlying pathophysiology are still poorly understood. We have established a whole IVD organ culture system with the ability to maintain entire discs with the endplates for several weeks under controlled nutrient and mechanical loading conditions.

Within this bioreactor, the beneficial or detrimental effects of nutrition, mechanical forces, and/or biochemical factors on disc cell viability and metabolic activity can be investigated. We have developed various defect and degeneration models, allowing us to design and evaluate appropriate biological treatment strategies. These include implantation of cells, delivery of anabolic, anti-catabolic or anti-inflammatory molecules, biomaterials or a combination thereof. Data from ex vivo models are also correlated to in vivo observations to identify molecular markers of IVD damage or degeneration.

To study the potential of new therapies for articular cartilage repair and regeneration, a bioreactor system applying multiaxial load to tissue-engineered constructs or osteo-chondral explants has been established. The bioreactor mimics the load and motion characteristics of an articulating joint. Chondral and osteochondral defect and disease models enable us to test tailored treatments under physiologically relevant mechanically loaded ex-vivo conditions. Cell- and material-based therapies as well as chondrogenic or anti-inflammatory factors are under investigation for cartilage repair and regeneration.

Biomaterials for skeletal repair can provide structural and mechanical features for the filling of defects, but also be a carrier for drugs, cells and biological factors. One of our goals is the development of 3D structures for bone, disc and cartilage tissue engineering, using tailored polymers and composites manufactured with additive manufacturing processes.

Our experience lies in the design of biocompatible, biodegradable polymers and their processing with controlled architecture and embedded biologics. A second field of research investigates the preparation of hyaluronan, a natural occurring biopolymer, based biomaterials which can be used to deliver drugs and cells. These injectable biodegradable materials have considerable potential in infection prophylaxis and tissues repair. We are also developing innovative technologies for the structuration and assembly of tissue-like matrices aiming to mimic for example, biological matrix mechanical and structural anisotropy. Additive manufacturing technologies will lead to the development of patient specific implants that can be tailor made to each individual case.

The Stem Cell focus area is particularly interested in stem cell therapies for bone and cartilage that could be applied within a clinical setting. We are increasingly investigating donor variation with the aim to predictively identify the potency of cells from individual donors. In the search for biomarkers to determine patient specific healing potential, exosomes and non-coding RNA sequences such as miRNA are increasingly being used as a diagnostic and therapeutic tool. The development of a serum-based biomarker approach would dramatically improve patient specific clinical decisions.

We also aim to investigate the role of mechanical and soluble factors in the activation of mesenchymal stem cells, and the promotion of differentiation and tissue repair. We can induce chondrogenic differentiation of human MSCs purely by mechanical stimulation and this is leading to new insights into cell behavior under loading conditions. Mechanical forces can be applied by way of rehabilitation protocols and are able to modify stem cell and immune cell function. Such studies are forming the basis of the emerging field of regenerative rehabilitation. In addition to the effect of load on direct differentiation, it is known that biomechanical stimulation can modulate the cell secretome. Investigating these changes could lead to the identification of new targets that may be present during articulation. This offers new avenues for potential clinical therapies.

The Musculoskeletal Infection team focusses their research activities on Fracture-Related Infection (FRI), with goals to optimise antibiotic prophylaxis, reduce the burden of therapeutic interventions, and study the impact of co-administered medication on infection. Our studies include preclinical in vitro and in vivo studies, as well as an increasing focus on observational studies in human patients.

In collaboration with ARI colleagues in the preclinical testing facility, we now have models that can mimic an open fracture, with a chronology and fixation that more accurately reflects clinical reality. Further advancements in our animal models in the past year include the controlled delivery of antimicrobials via the use of programmable, implantable pumps to more precisely control antibiotic dosing. In addition, we have investigated in more detail the use of anti-inflammatory medication in our animal studies and found it can have a major impact on treatment outcome, and so will be a focus for future studies with clear relevance for trauma patients. The preclinical evaluation of novel anti-infective interventions under Good Laboratory Practice (GLP) conditions has also continued in the past year, with two novel antimicrobial intervention studies performed in this space in the past year.

On the in vitro side, we have begun to develop an in vitro model for Staphylococcus aureus infection that has the potential to include human immune system cell-lines. This can not only reduce future animal studies but will also allow us to test interventions in a human-specific system. The antibiotic loaded hydrogel that has been in testing in ARI for several years, has now also been tested against MRSA biofilms and continues to be superior to aqueous solutions of antibiotics. In patient samples, we have made our first preparations for a study on the impact of antibiotic therapy on the human gut and skin microbiome. This is an under explored area of immense potential for bone health and will be a multi-year investigation with expert collaborations internationally.

A Fracture-Related Infection (FRI) consensus meeting in Davos in December 2016 achieved consensus on the fundamental features of FRI, and a proposal for defining the presence of FRI was reached. The establishment of this definition offers the opportunity to standardise preclinical research, improves the reporting of clinical studies and finally of course also aids in the decision-making during daily clinical practice. In the following 18 months, the expert group shifted attention to the next phase, validating the diagnostic criteria and develop treatment principles for FRI and a consensus on diagnosis and treatment principles for FRI.

In reflecting the greater complexity of this question, and to engage with other professional organisations, the group has grown to include external partners. Joining the ARI, AOTrauma and the AOTK Anti-Infection task force (AITF), is the European Bone and Joint Infection Society (EBJIS), the Orthopaedic Trauma Association (OTA), and the Pro-Implant Foundation, as well as a broadened panel of experts with extensive clinical experience in FRI. A first meeting of the expert group took place in Zrich in February. Prior to the meeting, the group was asked to review and consider the published literature on FRI, within nine specific concepts that were then presented for discussion in dedicated sessions during the meeting. The meeting engaged 35 experts and key opinion leaders in the field of FRI. Recommendations were developed on diagnosis and treatment of FRI. These guiding principles will be made available through scientific publications and an AO Bone Infection App.

Internal fracture fixation existed but only in individual hospitals and not globally, that is where ARI and AO came in and rolled this out globally and invented many new additions to this. ARI invented compression plates, minimal invasive surgery for trauma (plates, screws, nails etc.), locking plates for fractures close to articulating joints and for osteoporotic patients.

Currently tissue engineering and regenerative medicine (TERM) is in the research stage of its life cycle and has not really translated into routine surgical practice in orthopaedics. The combination of cells and biomaterials however has great potential in repair. The main issues are again regulatory, and the best way forward would be to develop techniques that can be applied in a single surgery within the operation room. Anything beyond this window and outside the operation room will take a significant amount of time to get approval and will likely not be surgeon friendly and obviously will be very costly.

TERM has its biggest potential in orthopaedics in the areas of cartilage repair (delaying classic orthopaedics), disc regeneration (back pain being one of the largest problems globally) and in bone this could be in large bone defects, but not a major area in fracture repair, where appropriate mechanical stimulation can be used to drive the repair to optimum levels and speed (which is also in the research stage). TERM has also potential in tendon and ligament repair.

Imaging and biomarkers for diagnostics and therapy (Theranostics) will be important in early detection of diseases or complications and then to prevent further development of the disease, delaying the time until classic orthopaedics is required. This may go beyond stopping the disease and towards tissue regeneration. The earlier the detection, the more potential for TERM.

The main challenges for a researcher are in translation and the fact that large companies today exist in a more complex regulatory environment, which means they are inclined to be very risk averse. This means in practice they need to see evidence of benefits or proof-of-concept in a clinical setting. The researchers in turn need to have greater awareness of these regulatory issues relating to medical development and CE approved manufacturers, than in the past. The increasingly complex regulatory environment of course has a greater impact on small companies and spin-offs, and can be seen as having a dampening effect on innovation development. Incremental innovations or solutions to niche problems will struggle to get the funding needed to carry them through the regulatory approval process. Researchers do benefit from this too, since in an environment in which companies are inclined to be more risk averse, they place a higher premium on solutions or concepts that have been through a rigorous clinical testing process. In orthopedics, we are approaching an innovation plateau with metals, and new technologies (such as tissue engineering, which is showing good results in research at present) still need to kick in to date little has translated to the patient in this field. 3D printing may have a place in spine or craniomaxillofacial areas, but offers little benefits to trauma in the most common areas for fracture repair. Surgeons who promote patient specific implants (PSI) in joint replacement have little proof that this offers clear improvements compared to current well-tested and proven joint replacement implants. The seamless integration of digitisation and robotic help into the patient treatment work-flow is another area to grow to help the surgeons in their daily practice.

Prof R. Geoff Richards

Director

AO Research Institute Davos

geoff.richards@aofoundation.org

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Advancing patient care through innovative orthopaedics - SciTech Europa