New Dress Code: Does the Material Used to Circumferentially Secure Cast Spacers Affect Cast Compliance?

Background: The rigid, circumferential nature of fiberglass casts puts patients at risk of increased pressures within the cast due to fracture-associated edema. Univalves are performed on casts with the placement of cast spacers to accommodate swelling. The cast spacers are often secured with materials such as plastic tape, silk tape, or cohesive bandage for stability. This investigation aims to assess the compliance (flexibility under pressure) of a valved cast with a 6 mm cast spacer secured with different materials. Methods: A volume 1-L saline bag was cast in a standard fashion, using a stockinette, cotton undercast padding, and fiberglass cast tape. The saline bag was connected to a pressure transducer system, and a 100 mL syringe insufflated saline into the system to simulate edema. The cast was univalved, and spacers were placed and secured circumferentially with the corresponding material (plastic tape, silk tape, cohesive bandage). Ten trials were performed for each material, including a control group where no material was used to secure the cast spacers. Cast compliance was calculated. Results: The average (SD) compliances were 2.80 (0.17) mL/mm Hg, 2.47 (0.29) mL/mm Hg, 2.53 (0.26) mL/mm Hg, and 2.54 (0.22) mL/mm Hg for the control, plastic tape, silk tape, and cohesive bandage groups, respectively. Compared with the control group, the plastic tape group had a significantly lower compliance ( P =0.025). In a noninferiority test, the compliance of the cohesive bandage group was noninferior to the plastic tape and silk tape groups mean difference in compliance: −0.068 mL/mm Hg, 95% CI (−0.176 to 0.312) and −0.040 mL/mm Hg, 95% CI (−0.209 to 0.237), respectively. Conclusion: Of the materials used, plastic tape had the lowest compliance, and the cohesive bandage had the highest. The differences in compliance between materials were not clinically significant. Therefore, we recommend that the material chosen to secure cast spacers be based on provider preference. Level of Evidence: Level V.