An Expanding Foam‐Fabric Orthopedic Cast

Abstract

Approximately 8 million orthopedic fractures are reported in the United States annually. [1] The most common form of medical treatment for pediatric patients with a long bone fracture, and some adult patients with nondisplaced fractures, is to immobilize and protect the limb during the healing process, typically using a cast molded from fiberglass or plaster. This approach requires the focused attention of a clinician during the processes of application and removal (≈20 min each session). [2] Casting also carries a risk of skin complications due to thermal injury or sharp cast edges, difficulty in monitoring swelling of soft tissue, and the need to keep the cast clean and dry in a typically noncompliant adolescent patient. [3] Moreover, the cast removal process is particularly problematic for pediatric populations, who are often distressed by (and in some cases injured by) the oscillatory saw used for cast removal. [4] The time and challenge of application, potential for iatrogenic injury and skin complications, as well as the costs associated with the application and removal of these casts offer significant potential for improvement using modern textile and soft robotic approaches. [5] The earliest examples of modern orthopedic casts were developed in the mid-19th century using cotton bandages containing plaster of Paris. [2] Although plaster of Paris still finds use in modern orthopedic practice for splinting purposes, knit fiberglass bandages impregnated with polyurethane were introduced in the 1970s as an alternative technology. Such fiberglass casts are more permeable to X-rays, weigh less, solidify faster, and are more durable than plaster casts. [2] They are, however more expensive and less malleable (not as easily molded during application) than plaster casts. [2] Fiberglass casts are often used as definitive treatment for pediatric fractures, requiring prolonged periods of immobilization. Their circumferential application makes skin monitoring difficult and may require cast valving using an oscillatory saw to allow for swelling. The process of cast valving, while reducing the risk of compartment syndrome (tissue damage caused by the blockage of circulation due to excessive pressure), also introduces the risk for the loss of fracture reduction. [6] Plaster casts are reserved for Traditional orthopedic casting strategies used in the treatment of fractured limbs, such as fiberglass and plaster-based tapes, suffer from several drawbacks, including technically challenging molding for application, occurrence of skin complications, and the requirement of a potentially hazardous oscillatory saw for removal, which is frightening for pediatric patients. This work presents the design and evaluation of a foam-fabric cast (FFC) to overcome these drawbacks by integrating strategies from soft materials engineering and functional apparel design. A fabric sleeve is designed to enable the reactive injection molding of a polymer foam and provide a form-fitting orthopedic cast for the human forearm-with sufficient mechanica...

3D Knitting for Pneumatic Soft Robotics

“…To form air-tight pouches to pressurize the 3D knit soft robots, oversized sealed bladders made from Strechlon 200 film (Fibre Glast, USA) were formed using previously demonstrated methods [13,79] and inserted into knit sleeves. Bladders were connected to tubing and closed using barbed fittings, cable ties, and Silpoxy adhesive (Smooth-On Inc., USA).…”