Avoiding Ring Avulsion Injuries With Silicone Rings: A Biomechanical Study.

PURPOSE: Finger avulsion injuries account for 5% of upper extremity injuries requiring evaluation in an emergency room. They are devastating injuries that require microvascular reconstruction or amputation. As public awareness rises, there is a growing market for silicone rings, with limited data on their ability to prevent ring avulsion injuries.

METHODS

Five cadaver forearms were attached to a custom fixture, allowing for ring avulsion simulations. Specifically designed silicone or metal rings of varying sizes (#4-#11) were assigned to one of five fingers on each forearm, based on fit. The contralateral corresponding finger was tested using a ring of the same size in the other material. A preload of 2 N was applied to each ring, and ultimate failure force was determined by applying an upward force at a loading rate of 500 mm/sec until failure. Additionally, a fifth cadaver forearm was used to determine the ultimate failure force of silicone rings in a clenched fist position.

RESULTS

The average ultimate failure force for silicone rings of all sizes was 53.0 N, compared to 495.2 N for metal rings of all sizes. The average ultimate failure force of silicone rings in the clenched fist position was increased across rings of all sizes, with an average of 99.9 N. There were no degloving injuries in the silicone ring avulsion group.

CONCLUSIONS

Biomechanically, silicone rings have a significantly lower failure force than metal rings and may help prevent ring avulsion injuries.

CLINICAL RELEVANCE: The use of silicone rings should be encouraged in professions where ring avulsion injuries are more likely, such as heavy labor.