Short arm splints for wrist stabilization: A mechanical material test and cadaveric radiography study

Area of Science:

• Orthopedics
• Biomechanical Engineering
• Materials Science

Background:

• Effective wrist immobilization is crucial for healing various hand and wrist conditions.
• Current splinting materials vary in their mechanical properties and stabilizing capabilities.
• Evidence-based recommendations require objective data on splint performance.

Purpose of the Study:

• To compare the wrist stabilizing properties of volar and dorsal short-arm splints made from four different materials.
• To evaluate the mechanical properties of plaster of Paris (PoP), Woodcast, X-lite, and 3D-printed polypropylene splinting materials.

Main Methods:

• Ten cadaveric arm specimens were used to test splints (PoP, Woodcast, X-lite, 3D-printed) in volar and dorsal configurations.
• Radiographic imaging assessed wrist flexion and extension under a 42 N load.
• A three-point bending test evaluated the mechanical properties of material sheets.

Main Results:

• Plaster of Paris (PoP) splints demonstrated the highest resistance to wrist flexion and extension when applied volarly.
• Woodcast showed improved flexion resistance dorsally compared to other materials, except PoP.
• 3D-printed splints exhibited the highest mean wrist flexion and extension, indicating less stabilization. PoP displayed significantly higher stiffness (146 N/mm) than other materials.

Conclusions:

• Plaster of Paris (PoP) offers superior wrist stabilizing properties and material stiffness compared to Woodcast, X-lite, and 3D-printed polypropylene.
• PoP is likely the preferred material for wrist immobilization due to its mechanical advantages.
• Further research may explore optimal configurations for newer materials.