Casting is not without danger, despite its reputation as a conservative procedure. Injuries can occur during the application procedure, cast valving, immobility, or cast removal. Researchers created an experimental model to study the safe parameters for the optimal duration between fiberglass cast application and bivalve for cast saw usage.

Short-arm fiberglass casts were created using a hospital sheet wrapped into a mimic “arm.” An appropriate cast saw method was employed, with the saw blade removed from the cast material between cuts. Ten castings were prepared for the control/no vacuum (N=5) and study/vacuum (N=5) groups. The temperature of the saw blade was recorded in 1-minute increments starting 3 minutes after the fiberglass was immersed in water. With a statistical threshold of P<0.05, a mixed factor analysis of variance analyzed differences in temperature change over time across groups.

Castings placed for 7 minutes had lower blade temperatures than casts set for 3, 4, 5, and 6 minutes. Without the use of a vacuum, the average temperature increases for the 3- to 7-minute set times were 10.08 (±1.42), 9.38 (±1.31), 9.32 (±1.85), 8.54 (±2.10), and 5.62°F (±2.42), respectively, and with the use of a vacuum, they were 9.40 (±1.14), 8.36 (±1.64), 7.84 (±2.05), 7.30 (±3.14), and 4.82°F (±2.59), respectively. The temperature change was substantially different from the maximum temperature (3 minutes) commencing at 7 minutes, regardless of vacuum usage (all P<0.043). 

The least rise in saw blade temperature was related to a minimum of 7 minutes of set time for a fiberglass cast before attempting to bivalve utilizing segmented cuts. The vacuum did not affect the temperature of the blades. Clinicians can show optimal techniques for reducing cast saw injuries.

Reference: journals.lww.com/jaaos/Abstract/2022/08010/Having_Patience_With_Our_Patients__A_Key_Technique.9.aspx