CASTomize 4D Printed Cast Versus Fibreglass Casts for Distal Radius Fractures
Phase: NA
Conditions: Distal Radius Fracture
Sponsor: Tan Tock Seng Hospital

 
Castomize protocol version 1.1 Dated 11/11//24 
 
 
 
 
CASTomize Pilot Study Protocol 
Principle investigator: Dr Michael Yam 
Co-investigator: Dr Trevor Binedell, Dr Bernice 
Heng 
Industrial collaborator: Abel Teo, Eleora Teo, 
Johannes Sunarko 

 
Castomize protocol version 1.1 Dated 11/11//24 
CASTomize pilot study protocol: a randomized controlled trial 
comparing CASTomize 4D printed cast versus standard of care 
fiberglass cast on fracture reduction and patient reported 
outcomes.   
 
Abstract 
Background: For many years, traditional fibreglass casting has been the gold standard of 
immobilisation for distal radius fractures (DRFs). However, the traditional method of casting has 
obvious disadvantages such as poor patient comfort, inability to be in contact with water, difficulty 
observing skin underneath and requiring multiple cast changes in the patients care journey.  This 
study compares the Castomize 4D printed casts versus the conventional fiberglass cast in fracture 
immobilisation, and various patient reported outcomes.  
Methods/design: This study is a randomised control trial comparing Castomize 4D printed cast 
versus conventional fibreglass casts in isolated conservatively treated distal radius fractures. The 
primary outcome measure is fracture reduction. Secondary outcome measures include patient 
reported outcome measures such as the Adult Rated Cast Evaluation Questionnaire (ARCEQ)[1][2], 
comfort of the cast, quality of life assessed with the EQ-5D-5L questionnaire[3], cost-effectiveness 
and adverse events occurrence. In total, 30 patients will be included and followed for 6 months.  
Trial registration: Pending 
Registration number: Pending 
 
 
 
 
 
 
 
 
Background 
Displaced distal radius fractures (DRF) are very common in the adult population and their incidence 
is still on rising trend due to aging population. This is an issue which is pervasive across all ages, but 
most common in the elderly. In 2019, 180 million fractures happened worldwide. An average of 5 
fracture incidents occurs every second. The current gold standard in fracture immobilisation is via 
the application of a fibreglass cast. However, the current fibreglass cast has multiple disadvantages. 
The cast is bulky, has poor ventilation and cannot come into contact with water. This gives patients 
considerable discomfort, and are unable to bathe and provide hygiene to their injured limb for the 
duration of the casting. Because the cast is not breathable, skin maceration, itchiness and wounds 

 
Castomize protocol version 1.1 Dated 11/11//24 
may become an issue. In this light, multiple casts changes become necessary to reduce the risk of 
soft tissue complications and to provide patient comfort. This increases the wastage of materials for 
the fibreglass casting as well as increases healthcare burden for the cast changes.  
Castomize has created a 4D printed cast with its proprietary materials and designs aimed at 
overcoming the challenges in the traditional casting methods. Its 4D printed casts are lightweight 
and breathable, allowing contact with water and hygiene. Its design facilitates visualisation of the 
skin and soft tissue conditions. It is also remouldable, potentially only requiring one device for the 
duration of the patients care journey.  
The design of the 4D printed cast was done in collaboration with orthopaedic clinicians, prosthetists 
and senior casting technicians optimised for clinical use. A biomechanical test was performed to 
evaluate the biomechanical properties of the 4D printed cast in comparison to the conventional 
fibreglass casts and were found to be less stiff and with a lower load to failure. This was however 
accessed to be not clinically significant.  
Therefore, this study aims to compares the Castomize 4D printed casts versus the conventional 
fiberglass cast in fracture immobilisation and various patient reported outcomes.  
 
 
Methods/design 
This manuscript is written according to the Consolidated Standards for Reporting Trials (CONSORT 
statement) and Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT 
guidelines). 
Objectives 
The primary aim of the study is to assess non inferiority of the Castomize 4D printed cast versus 
conventional fibreglass casts in fracture immobilisation and reduction.  
The secondary aim of the study is to assess differences in patient reported outcomes measures 
(ARCEQ, comfort of the cast, EQ-5D-5L, cost-effectiveness and adverse events occurrence) in the 
Castomize 4D printed cast versus conventional fibreglass casts.   
Design, participants, interventions and outcomes 
Study design and randomization 
A randomised controlled trial will be conducted in a single institution: TTSH.  
Patients will be recruited at the outpatient clinic. Patients who meet the inclusion and exclusion 
criteria will be recruited and randomised into 2 groups. Randomisation will be carried out via block 
randomisation via a computer generated randomization sequence.   
Group 1: Castomize 4D printed cast (Figure 2) 
Patients randomized to group 1 will undergo fracture immobilisation with the Castomize 4D printed 
cast via the care team (Casting technician/ clinical team). The Castomize 4D printed cast is 
appropriately heated and then moulded to the patients wrist as per usual manipulation and 
reduction techniques. The cast is held in position until hardened.  

 
Castomize protocol version 1.1 Dated 11/11//24 
Group 2: Conventional casting (Figure 1) 
Patients randomized to group 2 undergo fibreglass casting as per the standard of care.  
In both groups, post casting X-rays are taken to assure fracture reduction and recasting may be 
attempted in the event of inadequate fracture reduction.  
A patient information sheet will be provided to the patient explaining the study protocol, and what 
to look out for in caring for their casts.  
 
 
Inclusion criteria 
– Age ≥ 21 years 
– Distal radius fracture for conservative treatment within 3 weeks of initial injury 
 
Exclusion criteria 
– Concomitant injuries to the ipsilateral extremity, interfering with the treatment of the DRF 
(Example: concomitant elbow fracture that requires further immobilisation with a above elbow cast)  
– Inability to complete study forms due to any cognitive, mental issues. 
– Pregnant women 
 
Study procedures and timeline 
Measurements will take place at 6 time points as shown in Table 1. These time points are baseline 
(T0), 1 week (T1), 2 weeks (T2), 6 weeks (T3), 3 months (T4) and 6 months (T5) after inclusion in the 
study. At T0, baseline characteristics will be gathered. An inclusion form will be filled in by the 
treating physician providing fracture and treatment-specific information. Second, patients receive a 
questionnaire, providing predominantly patient and injury-specific information. The list of baseline 
characteristics is shown in Table 2. Patients receive questionnaires at T1 to T5. These questionnaires 
are carried out by phone call.  Posterior-anterior (PA) and lateral radiographs of the wrist will be 
taken at T0 (before and after reduction) and during follow-up at T1 –T4 as per standard of care. 
Physical examination of the wrist will take place at T4 and will be performed by the research 
team.Study visit may be administered via phone call. Functional tests will be performed at patient 
earliest appointment. 
 
Table 1 Schedule of activities 
 
T0  
T1  
T2  
T3 
T4 
T5 
 
Baseline 
D7±3 
D14 ±3 
D35 ± 7 
D84 ±14  
D168 ±21  
Inclusion 
form 
 
 
 
 
 
 
X-rays* 
 
 
 
 
 
 
Functional 
tests** 
 
 
 
 
 
 
VAS 
 
 
 
 
 
 
Photograph 
 
 
 
 
 
 
Comfort of 
cast  
 
 
 
 
 
 
Analgesic use 
 
 
 
 
 
 
EQ 5D5L 
 
*** 
 
 
 
 
ARCEQ 
 
 
 
 
 
 
MCQ- iMTA  
 
 
 
 
 
 

 
Castomize protocol version 1.1 Dated 11/11//24 
PCQ- iMTA  
 
 
 
 
 
 
 
 
 
 
 
 
 
*X-rays before and after reduction (obtained from standard of care results if available) 
**ROM, grip strength done by study team. ROM, DRUJ and Kapandji will be collected as part of 
standard of care if available 
*** EQ 5D5L status pre-fracture and post-fracture sustainment  
 
 
 
 
Table 2 Baseline characteristics   
Baseline characteristics 
 
Date of emergency room visit  
Sex 
Affected wrist 
Date of Birth 
Method of reduction 
 
 
 
 
Hand dominance  
 
Mechanisms of injury  
 
Smoking Status 
 
General medical history 
 
Previous injuries of the affected extremity 
 
La Fontaine criteria  
 
 
Outcome 
Primary outcome The primary outcome of this study is the occurrence of fracture displacement 
assessed on PA and lateral radiographs at 1, 2 and 6 weeks. Displacement of the radius is defined by: 
As compared to the post reduction radiograph at T0, Displacement of : > 15° of dorsal angulation, > 
20° of volar angulation, < 15° of radial inclination, > 3mm of radial shortening and > 2mm 
intraarticular 
step-off or gap. Measurements will be on standard PA and lateral radiographs of the wrist by trained 
members of the research team.  
 
Secondary outcomes An overview of measurements is shown in Table 1. 
• 
Comfort of the cast assessed via pictorial representation of pressure marks or areas of 
discomfort.  
• 
Severity of pain evaluated with the Visual analogue Score (VAS)   
• 
Patient will describe their average wrist symptoms over the past week on a scale of 0-10 
using Adult Rated Cast Evaluation Questionnaire (ARCEQ) [6][7]. 
• 
Quality of life will be assessed using the 5-level EuroQol (EQ-5D-5L) scoring questionnaire. 
• 
Cost-effectiveness will be measured using the Medical Consumption Questionnaire (iMCQ) 
and the Production Consumption Questionnaire (iPCQ) [8].  
• 
Physical examination:  
o Range of motion (ROM) of the wrist will be measured with a goniometer. ROM 
concerns dorsal flexion, volar flexion, radial deviation, ulnar deviation, pronation 
and supination. 
o Grip strength will be measured with a Jamar hydraulic hand dynamometer. The 
maximum score for each side over 3 attempts will be used  
o Specific testing of the wrist and hand will be performed namely: 
▪ 
distal radioulnar joint (DRUJ) stability tested with the DRUJ ballottement test 

 
Castomize protocol version 1.1 Dated 11/11//24 
▪ 
opposition of the thumb using the Kapandji score 
▪ 
finger stiffness will be measured with finger-to-palm distance, tested from 
the tip of the finger to the distal palmar crease when the fingers are in 
maximal active flexion  
ROM and grip strength on the injured side will be compared with the uninjured side. 
• 
Number of conversions to surgical treatment and other (serious) adverse events will be 
monitored. (Eg: Skin complications) 
 
It is expected that a proportion of patients will fail conservative treatment with displacement of the 
distal radius fracture at week 1 or week 2 follow up. These patients will continue with surgical 
fixation of their fractures and no further trial procedures will be required.  
 
Adverse events reporting 
All adverse events reported by the patient or observed by the treating physician or researcher will 
be recorded. Serious adverse events (SAE) will be reported to the Domain Specific Review Board 
(DSRB), which approved the protocol.  
 
Serious adverse events are defined as: 
– Skin related problems requiring surgical intervention (Eg: Ulcer, infection, necrosis) 
- Compartment syndrome 
- 
Cast related injury to the patient resulting in loss of limb or life 
 
Study related serious adverse events are defined as: 
– Compartment syndrome 
 
Fig 1 Conventional Fiberglass cast[9] 
 

 
Castomize protocol version 1.1 Dated 11/11//24 
 
Fig 2 CASTomize 4D printed cast 
 
Data analysis 
General descriptive statistics will be performed on baseline patient and fracture characteristics. 
Patients will be analysed according to the intention-to-treat principle. 
 
Primary outcome 
The primary outcome, fracture re-displacement, will be analysed using a mixed-effects logistic 
regression. To account for clustering, a random intercept for the hospitals will be used. Fixed effects 
will be the covariates we adjust for as reported in the literature, namely age, presence of 
osteoporosis, and fracture characteristics. If new prognostic factors will be identified and reported in 
the literature, these factors will also be added as covariates. 
 
Secondary outcomes 
For secondary outcomes, trends between baseline and follow-up time points (T0-T5) will be assessed 
using linear mixed models for repeated measures. This accounts for comfort of the cast, recovery of 
function and grip strength, pain severity (VAS), ARCEQ and EQ-5D-5L scores. The number of 
conversions to surgical fixation and complications will be determined using Fisher Exact or Chi-
square test, depending on the magnitude of results. 
 
Cost-effectiveness analysis 
Both cost-effectiveness (CEA) and cost-utility (CUA) analysis will be performed from a societal 
perspective. For the calculation of medical costs, we will use charges as published in Singapore 
guidelines as a proxy of real costs. The unit per price of the cast application in patients with DRF will 
be calculated with the microcosting method. Intramural costs (i.a. additional diagnostics, number of 
hospital visits, in case of hospital admission the length of stay etc.) are collected from the electronic 
health record. Productivity costs will be registered in detail by the iPCQ. The iMCQ and the iPCQ are 
validated by the Institute of Medical Technology Assessment (Erasmus University, Rotterdam, The 
Netherlands). 
The difference in costs and effects of CASTomize instead of a circumferential cast will be calculated 
as incremental cost-effectiveness ratio (ICER). The primary effect outcome measures will be the 
number of re-displacements for the CEA and quality-adjusted life years (QALY) for the CUA. QALYs 
will be measured, based on the Singaporean tariff for the EQ-5D-5L. 
The sensitivity analysis will assess the robustness of the results to changes in costs and effect 
parameters. Bootstrapping with 1000 replications will be used to estimate 95% confidence intervals 
around cost differences and the uncertainty surrounding the ICERs. This will be graphically presented 
on cost-effectiveness planes and acceptability curves using the net benefit framework. For the time 
horizon of 6 months, discounting is not necessary. 
 

 
Castomize protocol version 1.1 Dated 11/11//24 
Data management 
All data are handled confidentially and anonymized in compliance with the Singapore Personal Data 
Protection Act (PDPA). Personal data of participants will be changed by a study number. This number 
is used for all study documentation, study reports and publications. The key of this study number 
will be handled by an independent researcher. During the study period, all data will be collected and 
managed using GemsTracker electronic data capture tools. Paper case report forms are entered in 
GemsTracker by the researcher and the original paper case forms will be filed in the investigator site 
file at the recruiting hospital. All data is stored for 10 years. 
 
Data monitoring 
Since the study is labelled as low risk, a data safety monitoring board is not required.  
 
 
 
 
 
 
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