Generation of subject-specific, dynamic, multi-segment ankle and foot models to improve the design of foot and ankle foot orthoses

It has been estimated that up to 196 million Europeans have disabling foot and
ankle pain and that its prevalence is set to rise in an aging society with
increasing chronic long term conditions. Foot pain causes loss of function,
discomfort, and a general lowering of the patient's quality of life. Ankle and
foot orthoses are used to treat many of the conditions causing foot pain,
however, 70% of these medical devices are made using traditional techniques
relying on impressions casts, templates and hand fabrication. Patient supply
typically takes 28 days, the functional form of orthoses is difficult to
verify, and repeat prescriptions can be inaccurate. These traditional
approaches also limit design choice and personalised function to simple
parameters such as cushioning and range of motion.

Computer-based modelling of the human body - ranging from the force
interactions of joints to the way cells communicate with one and other - has
advanced significantly in the past few decades to a level where it is now an
important and useful tool for researchers working in the life sciences. These
models provide a method of simulating and assessing interventions that are
being developed; reducing the time and risk involved with trialling in humans.
The musculoskeletal field in particular is an area where extensive modelling
work has been successfully carried out, supporting the development and
assessment of a range of treatments and interventions.

In the field of foot biomechanics there is a growing body of research
incorporating computer modelling based on CT and MRI images, pressure
distribution measurements and gait analysis. This includes work on inflammation
of the plantar fascia, pressure assessment of the diabetic foot and therapeutic
footwear. This approach is particularly popular in this field because of the
difficulties relating to investigating the internal loading and movement of the
complex collection of bones and soft tissues within the foot.
It is therefore suggested that there is a great deal of potential for cutting
edge computer base musculoskeletal modelling technologies to be incorporated
into the process of developing orthotic interventions for the foot and ankle.
This could lead to changes in terms of reduced pain, improved function, more
comfort and higher quality of life for the patient; as well as reducing the
overall cost of the intervention to the health provider. This study aims to
begin exploiting this potential. The data generated in this study and through
the other aspects of the A-Footprint project of which it is part will be used
to advance the technology of foot orthotics.

To generate the information required to produce accurate and dynamic
computational models of the human foot and ankle for the purposes of orthotic
development.

This study is a feasibility/pilot study. It is a multicentre-study, between
Glasgow Caledonian University and University Hospital Maastricht. The data
acquisition will be independent, after acquisition the data will be pooled.
This datapool will be used to develop a biomechanical model of the foot. The
next step will be a larger trial for clinical evidence for the use of the model
for the development of (ankle-) foot ortheses, which will lead to cost
effectiveness.

One of the main ethical issues associated with this study are that detailed
examination of the participants' feet and gait will be undertaken, both a
physical examination by a qualified podiatrist and 3D medical imaging of the
foot using CT. These examinations will not be part of their standard care
regime. It is possible that in some cases pathologies will be detected as a
result of these examinations. Should this occur the consultant/GP responsible
for the participant's medical care will be notified so that the appropriate
management/treatments can be initiated.
Exposure to ionising radiation is another important ethical issue with this
study. Every effort has been made to keep exposure to a minimum, with the
fewest number of scans needed to generate the required data. During this study
only the foot and lower leg will be scanned. Participants will have the risks
of exposure to ionising radiation at the doses to be used in the study
described to them and it will be explained why the scan is an essential part of
the methodology. If potential participants have been exposed to ionising
radiation in the previous year, an assessment will be made by the radiological
team to determine if participation in this study would put them at unnecessary
risk. Particular attention has been paid to pregnant women and new mothers and
it has been emphasised in the Participant Information Sheet and Consent form
that these individuals must not take part in this study.
During the assessments of foot function, participants will be required to walk
barefoot which may result in some transient discomfort. The amount of barefoot
walking will be kept to a minimum and patients will be encouraged to rest when
necessary and will be able to stop testing at any time. There may also be some
slight irritation as a result of light abrasion and cleansing of the skin where
EMG electrodes will be attached (this is necessary to insure a high quality
signal). The MUMC+ have extensive experience of undertaking these types of
assessments and measurements in the populations being targeted by this study.
During imaging of the foot, the participant will be asked to push with their
foot against a fixed plate (this is so we can identify internal changes in the
foot that occur under loading). This force needs to be applied for around 30
seconds, and prior to the scan beginning the level of force the participant is
comfortable applying will be tested. (up to a level equivalent to 50% of body
weight).
The only other ethical issue which may arise relates to the extra time involved
in conducting these examinations. This will involve the participants giving up
their own time to attend MUMC+ for their appointments. This whole process is
estimated to take 4 hours.