A step in the right direction - comparing 3D printed orthoses and traditional orthoses in individuals with flat feet.

This preliminary study employs a within-subject single-blinded randomised crossover study design. Fifteen flat footed adults with heel pain in one foot will be recruited. This sample size is the maximum number of recruitment allowed within the funding allocation. Participants will be recruited from the CQUniversity Health Clinic. The inclusion criteria include: being over 18 years of age and having heel pain in one foot for more than 6 months. Exclusion criteria include having a BMI > 36 kgm2, any medical conditions affecting gait, skin allergies to double sided tape and adhesives. An information sheet will be provided which will explain the risks and benefits of their participation. They will be given the opportunity ask questions and have them answered to their satisfaction. They will attend an initial assessment session at the CQUniversity Health Clinic which will take about 1 hour. The potential participants need to provide written informed consent before being assessed by podiatrists registered with the Australian Health Practitioner Regulation Agency (AHPRA). Standard CQUniversity Health Clinic podiatry assessment forms will be used. The podiatrist will assess the potential participant to ensure that they fit the inclusion criteria and that their heel pain is clinically suitable for orthotic therapy. Those individuals who are excluded will be referred to the appropriate health care professional for continued care. Those who fully meet the inclusion criteria will have their foot moulds taken by podiatrists [MH and JN] with 3D foot scanning and with plaster casting. Foot moulds will be sent to the same external orthotic laboratory which will use 3D printing techniques and traditional methods to fabricate two pairs of orthotic devices. The foot scans and casts will be coded in order to blind the orthotic laboratory as to the individual whom the orthoses is intended. This will reduce potential bias in the manufacture process. When the two pairs of orthoses are ready, dimensions will be measured and compared. The same member of the research team will measure all the orthoses to ensure consistency in measurement. The participant will attend a second session lasting approximately 2 hours at the CQUniversity biomechanics laboratory for data collection. Participant's height and mass will be recorded at the start of the session followed by a three-dimensional gait analysis. Reflective markers will be attached to the participants. The reflective markers are tracked by a special camera system (Vicon Motion Systems Ltd, Oxford, UK) which only collects the reflection of the markers. No standard video of the participant is collected. Participants will then be asked to complete a series of walking trials (minimum 10 trials per condition) over a 8m walkway during which time, lower limb and foot kinematics(i.e. joint angles) and kinetics (i.e. forces),will be collected using an 8-camera Vicon motion capture system (Vicon Motion Systems Ltd, Oxford, UK) synchronised with an AMTI force plate (Advanced Mechanical Technology, Inc., Watertown, Massachusetts). Participants will complete the gait analysis under the three conditions: (1) without orthoses (control), (2) with the 3D printed orthoses, and (3) the traditionally made orthoses, in a randomised order. The order of conditions are determined by a random number software. The trials of the conditions will occur one after the other with a rest period of about 5 minutes in between trials. A standard canvas lace up shoe, modified with cut outs for the placement of reflective markers, will be supplied to the participant and used for the entire gait analysis.