Experimental spiral fractures. An in vitro biomechanical comparison of lag-screw fixation to plate fixation.
The rigidity and strength of fixation of experimental spiral fractures in canine tibias with triple lag-screw osteosynthesis were compared with fixation by six-hole dynamic compression plating (DCP). Lag-screw fixation was 71% to 77% as stiff in bending and 69% as stiff in torsion as plate fixation. When evaluated by torsion to failure, lag-screw specimens were 68% as strong as plate specimens. Although the difference in energy to failure in torsion was not statistically significant between the two methods, both fell considerably short of control values. The lag preparation was 9% as strong as intact controls, and the plate preparation was 21% as strong as intact controls. Long spiral fractures without comminution are amenable to triple lag-screw osteosynthesis with some loss of rigidity and strength when compared to single-plate fixation. This decrease in rigidity and strength may be outweighed by the avoidance of the stress protection phenomenon noted under rigid plates.
Cox
L G
LG
University of North Carolina, Chapel Hill 27599-7055.
Dahners
L E
LE
Gilbert
J A
JA
D000818:Animals; D001696:Biomechanical Phenomena; D001860:Bone Plates; D001863:Bone Screws; D004285:Dogs; D066298:In Vitro Techniques; D010027:Osteotomy / Q000379:methods; D013978:Tibial Fractures / Q000601:surgery*