From Feb 2022 to Nov 2022, we undertook a single-center prospective randomized trial involving 100 children with cast-immobilized stable upper limb fractures. These patients were randomized into either biobased polyester or synthetic fiberglass groups. All patients were regularly followed up till the cast removal which occurred approximately 3-4 weeks after immobilizing. Objective clinical findings and subjective patient questionnaire were all collected and analyzed.

The clinical trial was approved by the research ethics review committee of the author's hospital and informed consent was obtained from the legal guardian of each patient. Between Feb 2022 and Nov 2022, all children (age range, 4-15 years) with radiography-diagnosed stable upper limb fractures (including radius, ulna, and distal humerus fractures such as Garland type I supracondylar fractures of the humerus) [9] diagnosed at the orthopedic outpatient clinic or emergency room of a tertiary trauma center hospital were eligible for recruitment.

Inclusion Criteria:

• stable upper limb fractures (including radius, ulna, and distal humerus fractures such as Garland type I supracondylar fractures of the humerus) diagnosed at the orthopedic outpatient clinic or emergency room of a tertiary trauma center hospital

Exclusion Criteria:

• displaced or unstable fractures indicated for close or open reduction and fixation
• previous surgeries to the affected upper limb
• history of any chronic skin pathology (e.g., atopic dermatitis)
• known allergy to cast materials

the study protocol could be shared

one year