Stability of a cannulated screw versus a Kirschner wire for the proximal crescentic osteotomy of the first metatarsal: a biomechanical study.
The purpose of this study was to compare the stability of a Kirschner wire (K-wire) versus a single cannulated screw for fixation of the proximal crescentic first metatarsal osteotomy. Seven matched pairs of fresh-frozen human cadaver first metatarsal specimens were dissected out en bloc at the first metatarsal-medial cuneiform complex; right and left specimens were randomized as to fixation. In screw specimens, a cannulated screw was mounted from the proximal medial side of the metatarsal, traversing osteotomy and engaging the lateral diaphyseal cortical bone. In the corresponding specimen, a K-wire was placed from the distal medial metatarsal cortex oriented as close to the longitudinal metatarsal axis as possible. Using a materials testing machine, a continuous load was applied to the plantar aspect of the metatarsal head at a rate of 5 mm/min until a displacement of 10 mm was reached. The following parameters were measured: initial stiffness of the entire specimen, stiffness of the osteotomy, the force required to create a 1-mm displacement, the force required to create a 0.15-mm gap across the osteotomy, and the ultimate force to create the 10-mm displacement. Both specimen and osteotomy stiffness were found to be significantly higher for screw fixation versus the K-wire (P <.05). Although there was also a difference in the force-to-failure load in favor of screw fixation, this result was found not found to be statistically significant.
Bozkurt
Murat
M
Aarhus University Hospital, Aarhus, Denmark.
Tigaran
Constantin
C
Dalstra
Michel
M
Jensen
Niels Christian
NC
Linde
Frank
F
D001696:Biomechanical Phenomena; D001863:Bone Screws; D001864:Bone Wires; D002102:Cadaver; D006215:Hallux Valgus / Q000601:surgery*; D006801:Humans; D008422:Materials Testing; D008682:Metatarsal Bones / Q000601:surgery*; D010027:Osteotomy / Q000295:instrumentation / Q000379:methods*