Introduction: Traditional plaster and fiberglass casts are not waterproof. This experimental study compares the water-resistant and drying properties of two commercially available orthoses with traditional cast liners.

Methods: Two orthotic brace systems were selected for comparative waterproof testing with plaster and fiberglass traditional cast liners. This entailed water submersion for 10 seconds, followed by light drip drying for another 10 seconds. Moisture levels were then measured at four different locations immediately after drip drying and then every 15 minutes up to 45 minutes.

Results: The Zero-Cast Wx orthosis retained the least moisture after initial immersion and was fully dry within 45 minutes. The Exos upper extremity brace also demonstrated a low initial mean moisture content but lost little moisture during drying. In comparison, both the cotton-lined plaster cast and Delta Dr. cast liner systems demonstrated the greatest amount of water absorbed and moisture retention.

Discussion: Both orthotic brace systems demonstrated markedly less water absorption compared with the cotton-lined plaster cast and Delta Dr. cast liner systems. The Zero-Cast Wx was the only orthosis to fully dry in 45 minutes.

Conclusion: Both orthotic brace systems provide superior water-resistant properties to traditional cotton-lined plaster cast or fiberglass Delta Dr. cast liner systems.