OTA 2012 Posters

Scientific Poster #105 Upper Extremity OTA-2012

A Biomechanical Study of Distal Volar Radius Plates for the Treatment of Distal Radius Osteotomies: Are they Able to Withstand Cyclic Physiologic Loads Thus Allowing Early Active Range of Motion?

Alexandra C.R. Stratton, MD; Amy Hsiao, PhD; Andrew Furey, MD;
Craig Stone, MD; Chris Hamilton, MD;
Health Sciences Center, Memorial University of Newfoundland,
St. Johns, Newfoundland, Canada

Purpose: Multiple studies have tested distal radius plates on dorsal wedge osteotomies at physiologic load. It is not clear in the literature, however, whether volar locking plates are able to withstand active range of motion (ROM). Our study endeavored to determine whether volar distal radius locking plates used to stabilize dorsal distal radius osteotomies are able to withstand the force required for early active ROM postoperatively, thereby enabling basic activities of daily living (ADLs).

Methods: Dorsal wedge osteotomies were performed on 10 distal radii Sawbones with a 6-mm dorsal gap and 2-mm volar gap. Five pairs of distal radius plates were applied to fix the radii, four volar and one dorsal. Cyclic axial loading at 350 N was performed to simulate light ADLs and the constructs were cycled to failure. The load was calculated using 250 N to simulate the force of the tendons across the wrist joint plus 100 N for active wrist motion. The number of cycles leading to failure of the plates was recorded for each plate. Failure was defined as physical contact between the dorsal cortices (originally a 6-mm gap).

Results: The pair of dorsal plates outlasted all of the volar plates. Six of the eight volar locking plates failed within four cycles. One pair failed at 900 and 3000 cycles.

Conclusion: Volar locking plates to stabilize dorsal wedge osteotomies of the distal radius are not able to withstand the force required for active wrist ROM. Light ADLs are therefore not recommended following dorsal wedge osteotomy fixed with volar locking plates.

• The FDA has not cleared this drug and/or medical device for the use described in this presentation   (i.e., the drug or medical device is being discussed for an “off label” use).  ◆FDA information not available at time of printing. Δ OTA Grant.