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The effect of screw thread length on initial stability of Schatzker type 1 tibial plateau fracture fixation: a biomechanical study

View Article: PubMed Central - PubMed

ABSTRACT

Background: This study compares the cyclic loading properties and failure loads of two screw combinations on a synthetic Schatzker type 1 tibia fracture model. Our hypothesis was that after adequate compression with first a partially threaded screw, addition of a fully threaded screw would provide more stability than an addition of a second partially threaded screw.

Methods: The Schatzker type 1 tibial plateau fracture model was created. Fixation was obtained in group A (n = 10) with two partially threaded screws and in group B (n = 10) with one fully threaded screw and one partially threaded screw. Load-displacement evaluation was made at each 1000-cycle interval up to 10,000 cycles. Failure load was identified as the load creating a 2-mm displacement. Two-factor (groups and periods) repeated measurement analysis of variance and independent sample t tests were used.

Results: According to the two-factor repeated analysis, there was no significant difference for periods (p = 0.29) and time-period interaction (p = 0.59) (Wilk’s Lambda F value, 1.507 and 0.871, respectively). In the test of between-subject effects, there was no significant difference between groups in terms of cyclic loadings (p = 0.06, F = 4.065). However, in the t test for each 1000-cycle interval, the value of mean displacement in group B was significantly lower than that in group A in the initial, 1000-, 2000-, and 3000-cycle intervals (p = 0.023, 0.031, 0.025, 0.043, respectively). The mean displacement and standard deviations increased with the number of cycles. The mean range of displacement initially was 0.66 mm for group A and 0.36 mm for group B. The mean range of displacement after 10,000 cycles was 0.79 mm for group A and 0.44 mm for group B. The mean failure load value was 682 ± 234 N for group A and 835 ± 245 N for group B. In independent sample t tests, there were no significant differences between the two groups in terms of failure load (p > 0.05).

Conclusions: Obtaining fixation with one partially and one fully threaded screw can minimize displacement at the fracture site at early cyclic loadings.

No MeSH data available.


Time-displacement graphic of one sample. Initial and 10 cyclic loading tests were seen as 11 peaks total. Displacement was increasing because of the load to failure test
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Fig4: Time-displacement graphic of one sample. Initial and 10 cyclic loading tests were seen as 11 peaks total. Displacement was increasing because of the load to failure test

Mentions: Following the cyclic loading, a load to failure test was performed. The loading speed was identified as 5 mm/min, and the loading was maintained until 3 mm of displacement. The displacements were detected with an optical camera during this loading phase. The load that caused a 2-mm displacement was identified as the failure load. In one of the load to failure tests, technical errors occurred and meaningful values were not obtained. This measurement was excluded from the study. An example load-displacement graphic, consisting of an initial and 10 cyclic intervals and load to failure tests, is demonstrated in Fig. 4.Fig. 4


The effect of screw thread length on initial stability of Schatzker type 1 tibial plateau fracture fixation: a biomechanical study
Time-displacement graphic of one sample. Initial and 10 cyclic loading tests were seen as 11 peaks total. Displacement was increasing because of the load to failure test
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5120498&req=5

Fig4: Time-displacement graphic of one sample. Initial and 10 cyclic loading tests were seen as 11 peaks total. Displacement was increasing because of the load to failure test
Mentions: Following the cyclic loading, a load to failure test was performed. The loading speed was identified as 5 mm/min, and the loading was maintained until 3 mm of displacement. The displacements were detected with an optical camera during this loading phase. The load that caused a 2-mm displacement was identified as the failure load. In one of the load to failure tests, technical errors occurred and meaningful values were not obtained. This measurement was excluded from the study. An example load-displacement graphic, consisting of an initial and 10 cyclic intervals and load to failure tests, is demonstrated in Fig. 4.Fig. 4

View Article: PubMed Central - PubMed

ABSTRACT

Background: This study compares the cyclic loading properties and failure loads of two screw combinations on a synthetic Schatzker type 1 tibia fracture model. Our hypothesis was that after adequate compression with first a partially threaded screw, addition of a fully threaded screw would provide more stability than an addition of a second partially threaded screw.

Methods: The Schatzker type 1 tibial plateau fracture model was created. Fixation was obtained in group A (n = 10) with two partially threaded screws and in group B (n = 10) with one fully threaded screw and one partially threaded screw. Load-displacement evaluation was made at each 1000-cycle interval up to 10,000 cycles. Failure load was identified as the load creating a 2-mm displacement. Two-factor (groups and periods) repeated measurement analysis of variance and independent sample t tests were used.

Results: According to the two-factor repeated analysis, there was no significant difference for periods (p = 0.29) and time-period interaction (p = 0.59) (Wilk’s Lambda F value, 1.507 and 0.871, respectively). In the test of between-subject effects, there was no significant difference between groups in terms of cyclic loadings (p = 0.06, F = 4.065). However, in the t test for each 1000-cycle interval, the value of mean displacement in group B was significantly lower than that in group A in the initial, 1000-, 2000-, and 3000-cycle intervals (p = 0.023, 0.031, 0.025, 0.043, respectively). The mean displacement and standard deviations increased with the number of cycles. The mean range of displacement initially was 0.66 mm for group A and 0.36 mm for group B. The mean range of displacement after 10,000 cycles was 0.79 mm for group A and 0.44 mm for group B. The mean failure load value was 682 ± 234 N for group A and 835 ± 245 N for group B. In independent sample t tests, there were no significant differences between the two groups in terms of failure load (p > 0.05).

Conclusions: Obtaining fixation with one partially and one fully threaded screw can minimize displacement at the fracture site at early cyclic loadings.

No MeSH data available.