Comparison of a novel FiberWire-button construct versus metallic screw fixation in a syndesmotic injury model.
BACKGROUND
There is minimal experience with less rigid syndesmotic fixation devices which may approximate the normal distal tibio-fibular mechanics during healing. This study evaluates the ability of a FiberWire-button implant (Arthrex, Naples, FL) to maintain syndesmotic reduction as compared with a metallic screw.


METHODS
Ten matched fresh-frozen cadaveric ankle pairs with intact ligaments were tested (12.5 Nm external rotation force) to establish physiologic syndesmotic diastasis. The same force was applied to the ankles after sectioning of the syndesmotic and deltoid ligaments. Within the pairs, each limb was randomized to receive a FiberWire-button implant or a metallic screw (Synthes, Paoli, PA); the ankles were tested for syndesmotic diastasis with progressive external rotation force, from 2.5 Nm to 25 Nm (or failure).


RESULTS
There was no significant difference in diastasis amongst pairs with intact or sectioned syndesmosis (p=0.64 and p=0.80, respectively). There was a significantly greater diastasis in the FiberWire-button group at all external rotation loads (p<0.0001). Nine of the ten pairs failed (all through fracture of the distal fibula). There were no hardware failures. The metallic screw group failed at a lower load (mean 15 Nm) compared to the FiberWire-button group (mean 18 Nm, p=0.0004). The metallic screw group maintained syndesmotic reduction up to 5 Nm of force.


CONCLUSIONS
The FiberWire-button was unable to maintain syndesmotic reduction of the ankles at any of the forces applied. The ankles fixed with the FiberWire-button demonstrated significantly greater widening of the syndesmosis compared to the screw, at all loads.


CONCLUSIONS
The FiberWire-button implant may not maintain adequate ankle syndesmotic reduction in the immediate post-operative period relative to a metallic screw.
Forsythe
Kevin
K
Department of Orthopaedic Surgery and Rehabilitation, Loyola University Medical Center, 2160 South First Avenue, Maguire Center 1700, Maywood, IL 60153, USA. kcforsythe@hotmail.com
Freedman
Kevin B
KB
Stover
Michael D
MD
Patwardhan
Avinash G
AG
D000368:Aged; D016512:Ankle Injuries / Q000601:surgery*; D001863:Bone Screws; D002102:Cadaver; D019544:Equipment Failure Analysis; D005260:Female; D005360:Fibula / Q000293:injuries; D050723:Fractures, Bone / Q000209:etiology; D006801:Humans; D008023:Ligaments, Articular / Q000293:injuries / Q000601:surgery*; D008297:Male; D008422:Materials Testing; D008875:Middle Aged; D019736:Prostheses and Implants; D011897:Random Allocation; D012399:Rotation; D016474:Weight-Bearing