title: Distal tibiofibular syndesmosis fixation: a cadaveric, simulated fracture stabilization study comparing bioabsorbable and metallic single screw fixation.
abstract: Metal screws that are used for ruptured tibiofibular syndesmosis repair are often removed within 3 months of placement, suggesting the utility of bioabsorbable screws. A biomechanical study was performed to compare fixation of a simulated syndesmosis separation with a 5-mm oriented copolymer bioabsorbable (82:18 poly-L-lactic acid/poly-glycolic acid) versus a stainless steel screw. Eight pairs of cadaveric lower-leg specimens were cleaned and a pronation external rotation-type injury was created in each. The syndesmosis was fixed with a single, tricortical bioabsorbable screw in 1 ankle and a metal screw in the contralateral ankle (matched pairs). Sequential testing of the specimens showed that torsional stiffness of the fixed, relative to intact, specimens was nearly equivalent (0.730 +/- 0.260 for copolymer, 0.770 +/- 0.300 for stainless steel; P = .401). Application of 1000 cycles of axial load (90 to 900 N) resulted in a significant decrease ( P < .0001) in axial stiffness for each fixation method, but the relative decrease was equivalent for both ( P = .211). Failure torque (17.8 +/- 8.3 N.m copolymer, 21.0 +/- 11.5 N.m stainless steel; P = .238) and angle of rotation at failure (47.9 +/- 13.6 degrees copolymer, 42.0 +/- 11.5 degrees stainless steel; P = .199) were also nearly equivalent. It appears that the 5.0-mm diameter copolymer screw is biomechanically equivalent to the 5.0-mm diameter stainless steel screw for repair of syndesmosis disruption.
authors.affiliation: LSU Health Sciences Center, Shreveport, LA, USA.
authors.forename: Stephen
authors.initials: S
authors.lastname: Cox
authors.forename: Debi P
authors.initials: DP
authors.lastname: Mukherjee
authors.forename: Alan L
authors.initials: AL
authors.lastname: Ogden
authors.forename: Raymond H
authors.initials: RH
authors.lastname: Mayuex
authors.forename: Kalia K
authors.initials: KK
authors.lastname: Sadasivan
authors.forename: James A
authors.initials: JA
authors.lastname: Albright
authors.forename: William S
authors.initials: WS
authors.lastname: Pietrzak
mesh_terms: D020341:Absorbable Implants; D016512:Ankle Injuries / Q000601:surgery*; D000843:Ankle Joint / Q000601:surgery*; D001863:Bone Screws; D002102:Cadaver; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D050723:Fractures, Bone / Q000601:surgery; D006801:Humans; D008422:Materials Testing; D013193:Stainless Steel
chemical_list: D013193:Stainless Steel