Residency · Residency · Orthopedic Surgery

Casting, Splinting, and Traction: Fundamental Techniques

Introduction

Casting, splinting, and traction are foundational skills in orthopedic surgery that remain indispensable despite advances in surgical fixation. These non-operative techniques serve as primary treatment for many fractures, provide temporary stabilization before definitive surgery, and play a critical role in postoperative management. Mastery of these techniques requires understanding the biomechanical principles behind immobilization, the materials available, and the potential complications that arise from improper application.

Casting Techniques

Indications for Casting

Casting is used as definitive treatment of stable, minimally displaced fractures (such as distal radius and tibial shaft fractures in select patients), for post-reduction immobilization of fractures amenable to closed management, for pediatric fractures with significant remodeling potential, and for postoperative protection following tendon repair or ligament reconstruction.

Materials and Application

Plaster of Paris features an exothermic setting reaction, molds well, and is radiolucent, making it ideal for initial application and molding. Fiberglass is lighter, stronger, and available in water-resistant options, though it is less moldable than plaster. Proper application requires smooth, wrinkle-free stockinette and adequate cotton padding (typically 2-4 layers). Extra padding is applied over bony prominences including the malleoli, olecranon, and fibular head. Water temperature for dipping should be lukewarm (24-26 degrees Celsius) to allow adequate working time; hotter water accelerates setting and increases thermal injury risk.

Principles of Three-Point Molding

Three-point fixation creates a force system that maintains fracture reduction. The interosseous mold for forearm fractures separates the radius and ulna to prevent malrotation. The cast index (ratio of sagittal to coronal diameter) should approach 0.7 for optimal distal radius fracture control. Overly tight molding risks pressure sores, while insufficient molding results in loss of reduction.

Splinting Techniques

Indications for Splinting

Splinting is indicated for acute injuries with anticipated swelling where circumferential casting would be dangerous, for temporary stabilization prior to definitive surgical management, for injuries requiring frequent wound inspection, and for patients with soft tissue compromise or burns overlying the fracture.

Common Splint Types

The sugar-tong splint (upper extremity) prevents forearm rotation and is used for distal radius and forearm fractures. The posterior long arm splint provides elbow immobilization at 90 degrees of flexion. The ulnar gutter splint is used for fourth and fifth metacarpal and phalangeal fractures. The thumb spica splint is applied for scaphoid fractures and first metacarpal injuries. The posterior ankle splint is used for ankle fractures and Achilles tendon injuries. The bulky Jones dressing provides knee immobilization with maximum swelling control.

Application Principles

Splint material is typically 8-12 layers of plaster or pre-fabricated fiberglass. Adequate padding (minimum 4 layers of cotton) prevents pressure injuries. The splint should encompass two-thirds of the circumference of the extremity and is secured with elastic bandages, avoiding circumferential tape. Joints are maintained in a functional position unless specific reduction demands otherwise.

Traction

Principles of Skeletal Traction

Skeletal traction uses a pin or wire through bone to apply longitudinal force along the limb axis, restoring and maintaining limb length by counteracting muscular deforming forces. It is primarily used as a temporizing measure prior to definitive fixation. Weight applied is typically 10% of body weight for femoral traction as a starting point.

Common Traction Configurations

The distal femoral traction pin is placed from medial to lateral, 2 cm proximal to the superior pole of the patella and posterior to the mid-axis of the femur. The proximal tibial traction pin is placed from lateral to medial, 2 cm posterior to the tibial tubercle, with risk to the peroneal nerve on the lateral side. The calcaneal traction pin is used for tibial shaft fractures and placed from medial to lateral to protect the neurovascular bundle. Gardner-Wells tongs provide cervical spine traction for facet dislocations, with pins placed 1 cm above the pinna in line with the external auditory meatus.

Skin Traction

Buck traction applies longitudinal traction to the lower extremity via adhesive strips or boot. It is limited to 5 pounds (2.3 kg) maximum to avoid skin breakdown and is used for temporary comfort in hip fractures awaiting surgery. It is contraindicated in patients with fragile skin, peripheral vascular disease, or dermatologic conditions.

Monitoring Patients in Traction

Neurovascular checks are performed every 2-4 hours, assessing sensation, motor function, pulses, and capillary refill. Pin sites are inspected daily for signs of infection (erythema, drainage, loosening). Proper weight alignment must be ensured so that weights hang freely and do not rest on the floor or bed frame. Follow-up radiographs are obtained within 24 hours and after any weight adjustment.

Complications

Cast and Splint Complications

Compartment syndrome is the most feared complication; circumferential casts must be bivalved immediately if suspected. Thermal burns can occur because plaster generates heat during its exothermic setting reaction, with risk increasing with more layers and hotter water. Pressure sores develop over bony prominences from inadequate padding or indentation of wet cast material. Skin maceration results from moisture trapped beneath the cast, and patients should be instructed to keep casts dry. Joint stiffness from prolonged immobilization can cause contracture, making early mobilization of adjacent joints essential.

Traction Complications

Pin site infection ranges from superficial cellulitis to osteomyelitis and is managed with local care and antibiotics. Nerve injury results from improper pin placement, risking the peroneal nerve at the proximal tibia or the posterior tibial nerve at the calcaneus. Over-distraction from excessive traction weight can cause non-union or neurovascular stretch injury. Deep vein thrombosis affects immobilized patients and requires thromboprophylaxis.

Key Clinical Pearls

Always bivalve a circumferential cast in the acute setting if there is concern for swelling, as a bivalved cast with spread padding can reduce compartment pressure by up to 65%. Use plaster for initial fracture casts requiring precise molding, then consider conversion to fiberglass once swelling has resolved. Skeletal traction pins in the proximal tibia should be inserted from lateral to medial to minimize risk to the peroneal nerve, while calcaneal pins go medial to lateral to protect the neurovascular bundle. Instruct patients on the warning signs of compartment syndrome -- pain out of proportion, pain with passive stretch, progressive numbness -- and to seek emergency evaluation immediately.

References

1. Halanski M, Noonan KJ. Cast and splint immobilization: complications. Journal of the American Academy of Orthopaedic Surgeons. 2008;16(1):30-40.
2. Bong MR, Koval KJ, Egol KA. The history of intramedullary nailing and skeletal traction. Bulletin of the NYU Hospital for Joint Diseases. 2006;64(3-4):94-97.
3. Petrisor BA, Ekrol I, Court-Brown C. The epidemiology of casting and splinting. Injury. 2006;37(3):263-268.
4. Boyd AS, Benjamin HJ, Asplund C. Splints and casts: indications and methods. American Family Physician. 2009;80(5):491-499.

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