Back to Basics: Pediatric Casting Techniques, Pearls, and Pitfalls

Abstract

Cast application is a critical portion of pediatric orthopaedic surgery training and is being performed by a growing number of non-orthopaedic clinicians including primary care physicians and advanced practice providers (APPs). Given the tremendous remodeling potential of pediatric fractures, correct cast placement often serves as the definitive treatment in this age population as long as alignment is maintained. Proper cast application technique is typically taught through direct supervision from more senior clinicians, with little literature and few resources available for providers to review during the learning process. Given the myriad complications that can result from cast application or removal, including pressure sores and cast saw burns, a thorough review of proper cast technique is warranted. This review and technique guide attempts to illustrate appropriate upper and lower extremity fiberglass cast application (and waterproof casts), including pearls and pitfalls of cast placement. This basic guide may serve as a resource for all orthopaedic and non-orthopaedicproviders, including residents, APPs, and medical students in training. Level of Evidence: IV.

Keywords: casting; pediatric orthopaedics; resident education; technique guide.

Figure 1A-1H.

Upper Extremity Cast Padding Application. (1A) The optimal position of the patient during long arm cast placement is lying supine with the ipsilateral shoulder off of the table to allow room to work. The hips and feet should be towards the center of the table to prevent the patient from falling. (1B) Stockinette should be placed to the axilla proximally and just distal to the fingertips distally. A hole is cut for the thumb and in the antecubital fossa to prevent bunching of material in the flexion space. (1C) A hole is made in the center of the cast padding a few inches from the end of the roll. (1D) The patient’s thumb is placed through the hole and the padding at the end of the roll pads the metacarpal heads. (1E) The cast padding is rolled starting distally at the level of the metacarpal heads and overlapping the previous layer by 50% with each successive roll around the arm. The roll is held on the sides using the thumb and index finger to keep the cast padding taut while rolling to prevent wrinkles. (1F) Demonstrating the arm after 4 layers of padding have been placed. (1G) Cuffs of padding are made proximally, distally, and around the thumb by folding the cast padding in thirds. (1H) Three to four extra layers of padding are placed over the olecranon.

Figure 2A-2C.

Waterproof Cast Application. (1A) Two to three layers of waterproof cast padding are used for a waterproof cast, with padding cuffs similarly applied proximally and distally. A blue woven safety strip must then be applied to the volar and dorsal aspects of the forearm to aid in future cast removal to prevent thermal injury. (1B) After fiberglass application, the blue safety strips must be visible at the cast edges for later identification and removal. (1C) A plastic stick (Zip Stick, BSN Medical and Essity Company, Hamburg, Germany) seen here can be used as another measure to protect against cast saw burns and is placed beneath the cast in line with the blue safety strip when using the cast saw.

Figure 3A-3H.

Figure 3. Upper Extremity Cast Fiberglass Application. (3A-3D) Start rolling on the dorsal aspect of the distal forearm and cut a rectangle of cast material out at the thumb so that a layer is left in the first webspace. Thumb motion should not be restricted after cast placement. (3E-3G) When finished with the first roll, distally cut another thumb hole in the stockinette and roll back the stockinette over the cast material proximally and distally. (3H) Hold the roll on the sides using the thumb and index finger to allow for some tension while rolling to prevent wrinkles. Bring the cast material away from the arm prior to laying the cast material down (stress-relaxation) to prevent constriction of the cast.

Figure 4A-4G.

Upper Extremity Cast Molding and Valving. (4A) The interosseous mold is obtained by placing the heel of both palms on the dorsal and volar aspects of the forearm, interlocking the fingers together, and squeezing the heel of both palms together. (4B) Example of a three-point mold for a dorsally angulated fracture. The physician’s leg should be placed on the dorsal, proximal aspect of the forearm (see arrows). The distal hand is placed dorsally and just distal to the fracture site (fracture site demarcated by black line without arrow). The proximal hand is placed volarly just proximal to the fracture site and acts as a fulcrum. This allows for a net volar force to reduce and hold the dorsally angulated fracture. (4C) A supracondylar mold is obtained by squeezing the heels of both hands together over the supracondylar humerus. (4D-4E) Cast material should be just proximal to the metacarpal heads to allow for finger flexion. (4F) Valving should be performed with the arm on a stable surface. Preferred positioning for valving the dorsal aspect of the cast is with the arm over the patient’s body. (4G) The shoulder can be abducted and externally rotated to valve the volar part of the cast.

Figure 5A-5D.

Cast Index. (5A-5B) Example of a poorly molded long arm cast for a distal radius buckle fracture. The cast index is measured at 0.85, and the cast takes the shape of a tube. (5C-5D) Example of a well molded long arm cast. The cast index is 0.64 and the cast is molded to the shape of the arm. The arrows in image C indicate the three-point mold that was performed for this initially dorsally angulated distal both bone fracture.

Figure 6A-6E.

Lower Extremity Cast Padding. (6A) Roll the stockinette over the leg so that it is as proximal as possible (almost to the groin) and just distal to the toes distally. (6B-6D) Roll the cast padding starting distally at the level of the great toe and angled obliquely to match the cascade of the toes. Overlap the previous layer by 50% with each successive roll around the leg. (6E) Make cuffs of padding proximally and distally. Pad the bony prominences of the heel, malleoli, and anterior knee with an extra 3-4 layers of padding.

Figure 7A-7D.

Lower Extremity Cast Fiberglass Application. A: Start rolling the cast material distally just proximal to the cast padding. The tips of all the toes should be visible after cast placement. Overlap each layer by 50%. B: When finished with the first roll, roll back the stockinette over the cast material proximally and distally. C: The supramalleolar mold is performed by placing the heel of both palms just proximal to the medial and lateral malleoli, interlocking the fingers together, and squeezing the heel of both palms together. The foot can also be placed against the physician’s chest during this step to prevent equinus. The position of the knee must be carefully monitored to prevent creases. D: Final position of the long leg cast with the toes visible, the ankle in neutral dorsiflexion, and the knee in 30-45 degrees of flexion.