Stabilization of the posteromedial fragment in bicondylar tibial plateau fractures: a mechanical comparison of locking and nonlocking single and dual plating methods.
BACKGROUND
The objective of this study is to compare locking and nonlocking single and dual plating constructs in maintaining posteromedial fragment reduction in a bicondylar tibial plateau fracture model. We hypothesized that posteromedial fragment fixation with medial and lateral nonlocked constructs would tolerate higher loads than with lateral locked constructs alone.


METHODS
Thirty composite tibiae were fractured (AO 41-C1.3). Six constructs were tested: (1) lateral 3.5-mm conventional nonlocking proximal tibial plate (CP); (2) CP + posteromedial 3.5-mm limited contact dynamic compression plate; (3) CP + posteromedial 1/3 tubular plate (CP + 1/3 tubular); (4) 3.5-mm Zimmer Proximal Tibial Locking plate; (5) 3.5-mm Synthes Locking Compression plate; and (6) Less Invasive Stabilization System tibial plate. Specimens were cyclically loaded to failure or a maximum of 4000 N.


RESULTS
Failure occurred at the posteromedial fragment first. The CP + 1/3 tubular had the highest average load to failure (3040 N). The CP + 1/3 tubular demonstrated higher load at failure compared with the 3.5-mm Synthes Locking Compression plate (p = 0.0060) and the Less Invasive Stabilization System (p = 0.0360). The CP + 1/3 tubular did not demonstrate a difference in load at failure when compared with the CP (p = 0.4225), the CP + posteromedial 3.5-mm limited contact dynamic compression plate (p = 0.4799), or the 3.5-mm Zimmer Proximal Tibial Locking plate (p = 0.1595).


CONCLUSIONS
The posteromedial fragment tolerated higher loads with the CP + 1/3 tubular plate construct. The superiority of this construct may be caused by unreliable penetration of this fragment by the lateral locking screws.
Yoo
Brad J
BJ
Department of Orthopaedic Surgery, Harborview Medical Center, Seattle, Washington, USA. brad.yoo@ucdmc.ucdavis.edu
Beingessner
Daphne M
DM
Barei
David P
DP
D000328:Adult; D001860:Bone Plates / Q000592:standards; D001863:Bone Screws; D005593:Fracture Fixation, Internal / Q000379:methods*; D006801:Humans; D013314:Stress, Mechanical; D013978:Tibial Fractures / Q000601:surgery*; D016474:Weight-Bearing