The comparison of 3D printed and thermoplastic oval eight finger orthoses: A randomised crossover trial.

Participants were randomised to wear either a 3D printed or a thermoplastic oval eight finger orthosis for 24-hours, given a 24-hour washout period, followed by wearing the second orthosis for a further 24-hours. A 3D printed orthosis was created by the principal investigator, who created the orthosis initially on a CAD program and then printed via a desktop 3D printer, Lulzbot mini, using ABS 2mm filament. Each participant had there finger measured using a tape measure, at the middle and proximal phalanx of the index finger, and these measurement were input to the CAD program to create the custom made orthosis. The print time was approximately 30 minutes and then any minor rough aspects were smoothed with fine grit sandpaper. The thermoplastic was created by the principal investigator using current best practice methods. A 10 cm piece of Aquaplast thermoplastic was heated in a heat bath at 70 degrees. Once softened the participant was asked to rest their elbow on the table with their hand directly above, the principal investigator then molded the thermoplastic to the index finger at the PIPJ, creating the currently used orthosis. Any excess thermoplastic material was cut away. Once the two orthosis were created by the principal investigator the second investigator took all baseline measurement, with orthosis in place. The participant was randomised to wearing one of the two orthosis initially, which they were given verbal and written instructions on correct wearing and safety. The participant then wore the orthosis for 24 hours. They were then contacted by phone by the second investigator and outcome measures taken. The participant had a 24 hour washout period of not wearing an orthosis. The participant then wore the second of the two orthosis for a further 24 hours, again at the end of the wear period they were contact by phone by the second investigator to complete the outcome measures. The participant attended a secure room at the university to have the orthosis fitted, and base line measures completed. The participant wore the orthosis in their standard day to day life, and were contacted at a convenient time by phone to collect outcome measures. The participant were given a daily diary to write down any occasions that they removed the orthosis in the 24 hour wear period, and for what reason, they then read this to the second investigator when contacted by phone.