Derksen 2011.

Methods	Randomised controlled trial Study period: 1 year period – not stated
Participants	Red Cross Hospital, Vondellaan, Beverwijk, The Netherlands 68 children, aged 5 to 15 years, with an isolated greenstick or torus fracture of the distal radius Exclusion: polytrauma, osteogenesis imperfecta or other bone diseases, pre‐existent fractures or deformity of the injured forearm (congenital or acquired), or concurrent participation in another study Sex: 27 male (40%) Age: mean 9.8 years Fracture type: isolated greenstick (12) or torus (56) fracture of the distal radius Assigned: 34 (swim cast) / 34 (traditional cast) Analysed: 34 / 34 (at 4 weeks follow‐up)
Interventions	Initial application of a plaster of Paris splint at the emergency department. After a week, applied 1 of 2 casts. 1. Swim cast: air‐ventilating semi‐flexible Polyester cast manufactured without the use of a synthetic wool liner and thus applied directly over the protective stocking: only a single layer of synthetic cast was applied after a "reinforcing longuette" of the same cast material was used on the ulnar side. MOKcast technique used (Wierzimok 2017). Participants were instructed not to shower or swim just before going to bed but no additional instructions were given about avoiding swimming or going to the beach. 2. Traditional cast (made of polyurethane material, with a cotton liner). Participants receiving the traditional cast were advised to use a protective plastic bag when taking a shower or going for a swim Both types of casts were worn for 2 to 3 weeks. Children younger than 8 years were immobilised for a total of 3 weeks and children 8 years and older were immobilised for a total of 4 weeks, in accordance with hospital protocol. The cast was removed by employees of the plaster room. Control radiographs (anterior‐posterior and lateral) were made (additional to usual treatment)
Outcomes	Length of follow‐up: 4 weeks Function data: not reported Secondary displacement and radiological bone healing Complications: skin lesions (urticaria, redness, desquamation, pressure sores, maceration, inflammation); non‐union Participant and parent satisfaction (questionnaire) Activities during cast use: taking a shower, going for a swim Comfort (not reported) Costs (no data)
Funding and declarations of interest	Funding source: "None of the authors received financial or grant support for this study." Declarations of interest: reported, none
Notes	Authors gave a different number of people in the swim cast group (32 rather than 34) in the Discussion. The authors do not make clear whether all participants and their parents answered all the questionnaire questions Sent email to R Derksen 21.04.17. Asked for 1) more details on the traditional cast, in particular, its composition (polyester and polyurethane are both mentioned in the article); 2) if there were missing data for any of the outcomes and, if so, to supply the denominators for each group; 3) to provide an estimate of the costs of each of the casts? Email bounced so emails sent to co‐authors Dr Deij and Dr Breederveld 21.04.17. No reply
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: “Randomization was by the drawing of an envelope in the presence of employees of the plaster room who guided this process and occurred in blocks of ten patients.” No details but seems likely
Allocation concealment (selection bias)	Unclear risk	Quote: “Randomization was by the drawing of an envelope in the presence of employees of the plaster room who guided this process and occurred in blocks of ten patients.” Insufficient information. Some potential for predictability with fixed block size
Blinding of participants and personnel (performance bias) Subjective outcomes	High risk	Not blinded: care providers, children and their parents
Blinding of participants and personnel (performance bias) Objective outcomes	High risk	Not blinded: care providers, children and their parents
Blinding of outcome assessment (detection bias) Subjective outcomes	High risk	Children and their parents knew what interventions they had
Blinding of outcome assessment (detection bias) Objective outcomes	Low risk	Blinded assessment of clinical bone healing and for skin lesions. Quote: “Both the radiologist and the surgery resident [there were three of these] were blinded to the type of cast that was administered.”
Incomplete outcome data (attrition bias) Subjective outcomes	Unclear risk	No explicit report on whether there were missing questionnaire data. Small discrepancy in the Discussion
Incomplete outcome data (attrition bias) Objective outcomes	Low risk	Not reported. However, all percentages related closely to whole numbers
Selective reporting (reporting bias)	Unclear risk	No trial registration or protocol. Outcomes in Methods reported except for 1 on cast comfort
Other bias: major imbalance in baseline characteristics	Low risk	No major baseline imbalances
Other bias: performance bias	Unclear risk	No mention of clinician expertise
Other bias	Low risk	No other bias detected