Abstracts Posters SICOT-SOF meeting Gothenburg 2010 _2_

Poster
Topic: Biomaterials
Abstract number: 24303
SCANNING ELECTRON MICROSCOPIC (SEM) ANALYSIS OF FAILED
VARIAX® DISTAL RADIAL LOCKING PLATE USED FOR DISTAL RADIAL
OSTEOTOMY
Paraskumar MOHANLAL 1 , Chris JAMES 1 , Andrew AMIS 2 , Amit TOLAT 1
1 Medway Maritime Hospital, Medway (UNITED KINGDOM), 2 Imperial College
London, London (UNITED KINGDOM)
INTRODUCTION: Low profile designs, pre-contoured plates and options of poly axial
locking systems make locking plates the preferred implants for complex fracture
fixations and osteotomies of the distal radius. We present two cases of failure of
Stryker® VariAx® distal radial locking plate with scanning electron microscopic
(SEM) studies to analyse the pattern of failure. PATIENTS AND METHODS: A 76year-old
patient underwent dorsal open wedge corrective osteotomy with iliac crest
bone grafting and stabilisation with a dorsal VariAx® distal radial locking plate.
However, she presented at 6 weeks with non-traumatic wrist pain and radiographs
showed implant failure. Another 49-year-old underwent dorsal open wedge corrective
osteotomy and iliac crest bone grafting and fixation with a dorsal VariAx® distal radial
locking plate. She presented 3 months later with non-traumatic wrist pain and
radiographs showed broken plate through an unfilled screw hole at the osteotomy
site. In both patients, the broken plates were retrieved and visually examined for
manufacturing defects. It was then subject to scanning electron microscopic studies
and biomechanical analysis. CONCLUSION: This is the first case in the literature of
this multiaxial locking plate failing in this manner. We recommend that these plates if
used for dorsal osteotomy be inserted with caution and it may be necessary to
maintain some fixation closer to the osteotomy site than we achieved. We also
suggest improving the stiffness co-efficient of the plate by minimally increasing the
thickness of the plate at vulnerable points.
173