Effect of fibular plate fixation on rotational stability of simulated distal tibial fractures treated with intramedullary nailing.
BACKGROUND
The effect of an intact fibula on rotational stability after a distal tibial fracture has, to the best of our knowledge, not been clearly defined. We designed a cadaver study to clarify our clinical impression that fixation of the fibula with a plate increases rotational stability of distal tibial fractures fixed with a Russell-Taylor intramedullary nail.


METHODS
Seven matched pairs of embalmed human cadaveric legs and sixteen fresh-frozen human cadaveric legs, including one matched pair, were tested. To simulate fractures, 5-mm transverse segmental defects were created at the same level in the tibia and fibula, 7 cm proximal to the ankle joint in each bone. The tibia was stabilized with a 9-mm Russell-Taylor intramedullary nail that was statically locked with two proximal and two distal screws. Each specimen was tested without fibular fixation as well as with fibular fixation with a six-hole semitubular plate. A biaxial mechanical testing machine was used in torque control mode with an initial axial load of 53 to 71 N applied to the tibial condyle. Angular displacement was measured in 0.56-N-m torque increments to a maximal torque of 4.52 N-m (40 in-lb).


RESULTS
Initially, significantly less displacement (p < or = 0.05) was produced in the specimens with fibular plate fixation than in those without fibular plate fixation. The difference in angular displacement between the specimens treated with and without plate fixation was established at the first torque data point measured but did not increase as the torque was increased. No significant difference in the rotational stiffness was found between the specimens treated with and without plate fixation after measurement of the second torque data point (between 1.68 and 4.48 N-m).


CONCLUSIONS
Fibular plate fixation increased the initial rotational stability after distal tibial fracture compared with that provided by tibial intramedullary nailing alone. However, there was no difference in rotational structural stiffness between the specimens treated with and without plate fixation as applied torque was increased.
Kumar
Anant
A
University of Tennessee-Campbell Clinic, Memphis, Tennessee 38104, USA.
Charlebois
Steven J
SJ
Cain
E Lyle
EL
Smith
Richard A
RA
Daniels
A U
AU
Crates
John M
JM
D000368:Aged; D000369:Aged, 80 and over; D016512:Ankle Injuries / Q000503:physiopathology / Q000601:surgery*; D000843:Ankle Joint / Q000502:physiology / Q000601:surgery; D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D002102:Cadaver; D005260:Female; D005360:Fibula / Q000502:physiology / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000295:instrumentation*; D005594:Fracture Fixation, Intramedullary; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology / Q000601:surgery*; D008297:Male; D008953:Models, Anatomic; D013978:Tibial Fractures / Q000503:physiopathology / Q000601:surgery*; D019415:Torque