Comparative strength of elbow splint designs: a new splint design as a stronger alternative to posterior splints

Abstract

Background: Musculoskeletal injuries of the upper extremity are frequently treated with temporary external immobilization. Traditionally, long arm posterior splints have been used to limit flexion/extension of the elbow. However, long arm posterior splints have been observed to fail clinically, necessitating a stronger alternative. In this study, we assessed the biomechanical strength of the long arm posterior splint compared with a new spiral splint design.

Methods: One male and one female participant were placed 10 times in long arm posterior splints and 10 times in spiral splints. Both splint types were subjected to a downward mechanical load of 39.2 N (4 kg) and assessed for a change in both flexion/extension and pronation/supination.

Results: There was no significant difference in starting position or starting flexion/extension between the 2 splint designs. Posterior splints allowed significantly greater initial pronation/supination compared with spiral splints. Both splint groups had significant increases in flexion/extension and pronation/supination compared with their starting ranges of motion. There was no significant difference in the change in pronation/supination between the 2 splint groups. Finally, posterior splints allowed a significantly greater change in flexion/extension compared with spiral splints.

Conclusion: Spiral splints offered less initial pronation/supination than long arm posterior splints. Furthermore, spiral splints are able to resist flexion/extension of the elbow after application of a downward mechanical load better than posterior splints, thus suggesting spiral splints are mechanically superior to long arm posterior splints.

Keywords: Spiral splint; biomechanics; elbow; forearm; immobilization; posterior splint.