Waterproof Casts Maintain Reduction and Decrease Unplanned Cast Changes.

Background: This study compares clinical outcomes of waterproof vs standard casting in pediatric patients with nonoperative upper and lower extremity fractures. Methods: A single-institution retrospective review identified 516 pediatric patients treated with casting for nonoperative upper or lower extremity fractures at a single institution between January 2020 and December 2021. Casts were categorized by liner material. Primary outcomes included cast changes (planned and unplanned), casting duration, and complication rates. Secondary outcomes included in-cast displacement, casting failure, need for repeat reduction, and surgical intervention. A subgroup analysis of 209 displaced forearm fractures was completed. The change in radiographic anteroposterior (AP) and lateral angulation and translation from initial fracture reduction to cast removal was calculated and compared between groups. χ2 and Fisher's exact tests were used to compare categorical variables, and generalized linear models were used to compare continuous variables. Results: There were no significant differences in AP or lateral angulation and translation across cast materials, fracture bones, or the number of unplanned cast changes. Waterproof casts had significantly fewer total cast changes (9.9% vs 39.8%, P < .001), with most changes in both groups being unplanned. Mean casting duration was shorter in the waterproof group (27.0 ± 10.8 days) vs the standard group (29.5 ± 12.4 days, P = .025), while total duration of care was similar (35.2 vs 35.9 days, P = .826). In-cast displacement occurred less frequently with waterproof casts (16.3% vs 24.4%, P = .045). No significant differences were observed in casting failure (0.8%, P = .604), repeat closed reduction (0.6%, P = .554), or surgical intervention (0.8%, P = .604). Skin complications were more frequent with standard casts (3.6% vs 1.2%), though not statistically significant (P = .157). Conclusion: Waterproof casts are associated with reduced unplanned cast changes and shorter casting duration without increased complications or failure when compared to standard cotton liners. Additionally, waterproof and standard cotton liners are equally effective at maintaining reduction of displaced forearm fractures in pediatric patients. These findings support the use of waterproof casting as a safe and convenient alternative to standard cotton-lined casts for pediatric fractures. Key Concepts: (1)Waterproof lined casts maintained reduction, measured by anteroposterior and lateral angulation and translation, of displaced pediatric forearm fractures similar to standard cotton-lined casts.(2)Waterproof lined casts required significantly fewer unplanned cast changes when compared with that of standard cotton-lined casts.(3)The rate of cast failure and in-cast displacement was equivalent between waterproof casts and standard casts in pediatric patients. Level of Evidence: III.