Abstract
Background Volar locking plate fixation (VLP) is commonly used to treat distal radius fractures
(DRF). Risk of dorsal compartment injury with distal screw hole fixation has been
studied; however, the risk with proximal screw hole fixation is not well studied.
Purpose The goal of this study was to investigate the risk of dorsal structure injury from
the screw holes proximal to the two distal rows.
Methods Nine cadaveric forearms were used. After volar distal radius exposure, a long VLP
was applied. Kirschner wires were placed through the most proximal holes into the
dorsal compartments. The extensor structures penetrated were noted and tagged with
hemoclips. The distance from the dorsal cortex to the structures was measured.
Results The abductor pollicis longus (APL) and extensor pollicis brevis (EPB) muscle bodies
were only penetrated; no tendons were penetrated. Proportion of muscle penetration
increased with the more proximal screw holes. EPB was more likely to be penetrated
distally and APL proximally; both were injured at holes 2 and 3. The extensors were
2 mm from the dorsal cortex of the radius on average; this did not decrease with compression
of the forearm.
Conclusions This is the first study to examine the anatomic risk of extensor structure injury
with VLP proximal screw hole penetration. No extensor tendons were penetrated by these
proximal screw holes; first dorsal compartment muscle bellies may be irritated with
overpenetration. Our findings suggest that proximal VLP screws do not need to be downsized
if they are not over 2 mm prominent.
Keywords
distal radius - volar locking plate - proximal screw hole - extensor injury - screw
overpenetration - cadaveric
