Is a short‑arm splint applied on the dorsal (back) or volar (palmar) side of the forearm and wrist?

Short Arm Splint Application: Volar vs. Dorsal Placement

Short arm splints can be applied on either the volar (palmar) or dorsal surface of the forearm and wrist, with volar placement being the most common approach for most wrist and hand injuries, though specific clinical scenarios may warrant dorsal or combined volar-dorsal application.

Primary Application Approach

Volar (Palmar) Splinting

• Volar splints are the standard approach for most wrist stabilization needs, providing effective immobilization while allowing for swelling accommodation 1.
• Volar placement demonstrates superior mechanical properties when using plaster of Paris, showing the highest capability to resist both wrist flexion and extension compared to other materials 1.
• The distal end of a volar short arm splint should be positioned 1 cm proximal to the transverse skin folding line (the line from the radial thenar crease to the ulnar distal transverse palmar crease) to preserve full metacarpophalangeal joint motion 2.
• When properly positioned at this location, the splint allows 99% of normal MCPJ flexion (90° mean angle), which is critical for preventing hand stiffness 2.

Dorsal Splinting

• Dorsal splints are an alternative placement option, particularly effective when using certain materials like Woodcast, which shows lower wrist flexion angles when applied dorsally 1.
• Dorsal application may be preferred in specific clinical scenarios where volar skin integrity is compromised or when monitoring volar structures is necessary 1.

Combined Volar-Dorsal Application

• Volar-dorsal splints (using both surfaces simultaneously) are commonly employed for distal radius fractures requiring more rigid immobilization 3.
• Combined volar-dorsal splinting shows comparable loss of reduction rates (25.0%) to sugar-tong splints (28.8%) for distal radius fractures, with no significant difference in maintaining radial length or volar tilt 3.
• This approach provides circumferential support without the complete encirclement of a cast, allowing for swelling accommodation 3.

Material Selection Impact

• Plaster of Paris applied volarly provides the stiffest immobilization (146 N/mm stiffness) compared to Woodcast, X-lite, or 3D-printed materials (≤7.7 N/mm) 1.
• For maximal wrist stabilization requirements, plaster of Paris remains the preferred material choice despite newer alternatives 1.
• Woodcast, X-lite, and 3D-printed polypropylene materials show similar mechanical properties to each other but significantly less stiffness than plaster 1.

Critical Application Principles

Positioning to Preserve Function

• Avoid extending the splint too distally: placement at the transverse skin folding line or 1 cm distal reduces MCPJ flexion to only 62% of normal (56° mean angle), causing significant functional impairment 2.
• Radiographically, the optimal distal end position is at 44% of the total metacarpal bone length, which corresponds to approximately 29 mm proximal to the metacarpal heads 2.

Preventing Complications

• Begin active finger motion exercises immediately for all unaffected joints to prevent finger stiffness, which can be extremely difficult to treat after healing 4.
• Active motion does not adversely affect adequately stabilized fractures 4.
• Immobilization-related complications (skin irritation, muscle atrophy) occur in approximately 14.7% of cases 5, 6.

Duration and Follow-up

• Immobilize for 3-4 weeks with radiographic follow-up at approximately 3 weeks and at cessation of immobilization 4.
• The average splint duration is approximately 24 days 5.
• Transition to aggressive finger and hand motion exercises when immobilization is discontinued 4.

Common Pitfalls to Avoid

• Over-immobilization of unaffected fingers: This dramatically increases the risk of hand stiffness and functional impairment 4.
• Distal placement error: Applying the volar splint at or distal to the transverse skin crease severely restricts MCPJ motion 2.
• Prolonged immobilization beyond 4 weeks: This increases joint stiffness requiring additional therapy without providing additional benefit 4.
• Inadequate padding: The splint should be padded and comfortably tight but not constrictive, allowing a finger to slip underneath 4.