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A Comparison of Acute Pull‐Out Strength Between Two‐Way and One‐Way Transfixation Pin Insertion for External Skeletal Fixation in Canine Bone
Author(s) -
DERNELL WILLIAM S.,
HARARI JOSEPH,
BLACKKETTER DONALD M.
Publication year - 1993
Publication title -
veterinary surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.652
H-Index - 79
eISSN - 1532-950X
pISSN - 0161-3499
DOI - 10.1111/j.1532-950x.1993.tb01683.x
Subject(s) - medicine , external fixator , fixation (population genetics) , cadaver , metaphysis , orthodontics , diaphysis , universal testing machine , external fixation , anatomy , orthopedic surgery , surgery , composite material , materials science , ultimate tensile strength , population , environmental health
This study tested the hypothesis that two‐way insertion of an external skeletal fixator trans‐fixation pin would weaken the pin‐bone interface. Smooth and partially threaded (end) trans‐fixation pins were placed in tibiae of 32 cadavers by slow speed drilling or hand placement through a predrilled pilot hole. In one bone of each tibial pair, pins were inserted 2 cm beyond the distal cortex and retracted to a predetermined position (two‐way). In the contralateral limb, the pins were inserted in one forward motion to the predetermined position (one‐way). The peak force (Newtons) required to extract the pins (pull‐out strength) axially at a rate of 1 mm/sec was determined by using a universal testing machine. A significant (p < .05) decrease in pull‐out strength was found in pins placed by two‐way insertion (674 +/‐ 410) as opposed to one‐way insertion (766 +/‐ 432). The results of this in vitro study suggest that one‐way insertion should be used clinically to decrease weakening of the pin‐bone interface and prevent possible failure of external fixators. A significantly greater pull‐out strength was found for threaded pins placed in the proximal diaphysis (1459 +/‐ 330 Newtons) compared to the distal metaphysis (873 +/‐ 297 Newtons).