Targeting good quality bone with an orthopaedic smart drill

The two most pertinent problems facing the ageing population are keeping physically and mentally active. We aim to keep the ageing population moving through longer lasting total hip replacement (THR). Demand for THR is forecast to substantially increase in both primary and revision THR (100% for both by 2030, in the USA alone, Kurtz et al). Key features of the market are Europe and USA, with the US accounting for nearly 50 % and Europe contributing to around 30 % of total procedures worldwide [Singh et al].  A survey including 18 countries with a total population of 755 million showed that on average for primary and revision total knee procedures there were 175 procedures per 100,000 population (range 8.8 per 100,000 population in Romania to 234 per 100,000 population in USA) [Singh et al].  Much growth in demand is occurring because younger patients are now likely to outlive their implants and require subsequent revision surgeries and Kurtz's prediction of 100% increase in demand for revision is likely to double when we consider the problem worldwide.

It is possible to map bone quality (left, above) but not possible to find good bone.

Whilst growth in the THR market looks inevitable, success of the implants used in terms of longevity, function and ease of surgical implantation requires pre-competitive research. For example, research can deliver improved surgical techniques, for all surgeons and all types of patients, is applicable to all manufacturers of implants, and therefore deemed "pre-competitive", will result in improved patient outcomes. We aim to do this using SMART surgical tools.

THR was described as the "operation of the 20th century" and reached the masses in the 1970s, so we are now dealing with the inevitable consequences of worn out hip replacements, 15, 20, and even 30 years down the line. Solving this involves sophisticated solutions to aid the surgeon in performing the (revision) operation 2nd, 3rd and even 4th time around. Our solutions aim to develop smart applications and computer guided tools for surgeons dealing with complex hip problems.

The aim of the proposed PhD programme is to develop an orthopaedic smart drill chuck to sense good quality bone and guide the surgeon to orientate the drill accordingly. 

The objectives of the proposed PhD are to: 

1. Design and prototype a force/torque drill chuck sensor to be retrofitted into existing surgical drill tools
2. Characterise and model bone using animal and human models
3. Develop an algorithm that takes drill position/orientation/penetration, force/torque information and measures drill-to-bone friction as a function of bone quality
4. Integrate drill tool with off-the-shelf 3D computer guidance instrumentation for position, orientation with respect to bone
5. Conduct a short proof-of-concept trial to show the efficacy of the new smart drill

Supervisors:

Rui Loureiro

Alister Hart

Johann Henckel