Enhanced surgical treatments for hip osteoarthritis

Lead Research Organisation: University of Leeds
Department Name: Mechanical Engineering

Abstract

Over 80 million patients worldwide suffer from hip osteoarthritis, and increasing numbers of patients are requiring total hip replacement surgery. This is considered to be a successful intervention, however, an ageing population with increasing orthopaedic treatment needs, greater levels of obesity and patient expectations, and reducing healthcare budgets and surgical training are conspiring to challenge this success. There is also increasing demand for surgical treatments in younger patients that will delay the need for hip replacement surgery, these interventions reshape bone and repair soft tissue.

One of the major causes of failure in the natural hip and in hip replacements is impingement, where there is a mechanical abutment between bone on the femoral side and hip socket or hip replacement components. In the natural hip, surgery reshaping the bone can reduce this impingement and soft tissue damage can be repaired; however, the effects of the amount of bone that is removed is not well understood nor is the best way to repair soft tissue. The number of hip replacements needing to be removed from patients and replaced with a new one in revision surgery is increasing; damage to the cup rim because of impingement is often implicated. It is known that this is more likely if the components are not well aligned relative to each another, or relative to the load direction experienced in the body.

In this proposal, I seek to ensure long term outcomes of early intervention and hip replacement surgery are always optimum by negating concerns about impingement. To do this, I will develop an experimental anatomical hip simulator. The simulator will apply loads and motions to the hip similar to those observed clinically, and include high fidelity phantoms that mimic the natural hip, into which hip replacement components can also be implanted.

This anatomical simulator will be used to assess how variables such as those associated with the patient (e.g. their bony geometry), the extent of early intervention surgery (e.g. the amount of bone removed) or the design of the prosthesis and how the hip is aligned in the body will affect the likelihood of impingement. This improved understanding of factors affecting the likelihood and severity of impingement will enable better guidance on how the surgery should be performed to optimise outcomes to be provided.

I will work with orthopaedic surgeons to integrate this improved understanding into their clinical practice and with an orthopaedic company to integrate the findings into new product development processes; so that future interventions and devices can be designed to provide better outcomes for all patients.

Planned Impact

Over 80 million people worldwide suffer from hip osteoarthritis and it presents an increasing burden on healthcare systems. There are growing clinical and economic needs to develop more robust surgical interventions that provide optimum outcomes that do not fail due to impingement in all patients irrespective of surgeon experience and deliver longer lasting interventions to meet the demands of an ageing, active population and reduce the rising cost of revision surgery. The longer term impacts of this research will provide optimised surgical hip interventions, benefiting patients, healthcare providers and the orthopaedic industry. In the shorter term, this research will impact on clinicians in providing guidance on important parameters to consider in early intervention surgery and optimum component placement in hip replacement, industry will benefit from new methodologies for pre-clinical testing; regulatory and standard agencies in developing methods that enable surgical and patient variation to be incorporated into pre-clinical testing, and academia in developing new methodologies and highly skilled researchers, as well as promoting medical engineering to potential engineers of the future.

More specifically, this proposal will provide:
- Improved understanding of the factors affecting early intervention surgery. Proper patient selection and precise surgical technique are critical to successful outcomes, yet evidence is limited. This research will provide underpinning science on the effects of contact conditions in the hip on likelihood of damage.
- Improved definition of design, surgical and patient factors on mechanical failure of hip replacements. Early failure is often directly or indirectly associated with impingement and mechanical failure, yet how surgeon, patient and design variables interact to cause this is not well defined. Evidence will be provided to give surgeons clear guidance on component positioning in stratified (based on patient imaging) patient groups, to ensure optimum outcomes.
- More reliable patient outcomes, enhancing quality of life. Research from this proposal will inform tools and understanding that clinicians have at the planning stage (and in training) of an intervention, to better understand the interaction of variables on outcome. This will be used to ensure the right patient, gets the right treatment at the right time delivered optimally. Thus reducing the need for further interventions and/or revision surgery, which are economically and socially costly.
- Increased competitiveness of commercial partners, and wider community, a platform to pre-clinically assess innovations in hip surgery that goes significantly beyond what is currently available will be developed and demonstrated. Project Partner Simulation Solutions will benefit following the co-development of a novel simulator that they can sell commercially across the world. DePuy Synthes and industry more widely, will benefit from enhanced methodologies to evaluate interventions and opportunity to incorporate better definition of the tolerances needed for success into surgical delivery. In terms of early intervention surgery, the regenerative medicine and medical device community will benefit from such capabilities providing exciting scope to innovate new repair strategies that there are currently no in vitro methods available to assess.
- Improved pre-clinical testing processes, that reflect clinical failure modes (in particularly, with reference to hip replacements). These will be proposed to standards and regulatory agencies and I will advocate for improved methods that consider surgical and patient variation.
- Skilled researchers, this proposal will provide multi-disciplinary training for researchers working with industry and clinicians to optimise clinical outcomes. I will be supported to maximise my leadership potential, rapidly accelerating my long-term research vision.

Publications

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