PURPOSE: The use of new headless compression screws (HCSs) for scaphoid fixation is growing, but the nonunion rate has remained constant. The aim of this study was to compare the stability of fixation resulting from four modern HCSs using a simulated @entity174 model to determine the optimal screw design(s). METHODS: We tested 40 fresh-frozen cadaver scaphoids treated with the Acumed Acutrak 2 mini (AA), the KLS @entity2100 ( @entity2100 ), the Stryker TwinFix (ST) and the Synthes HCS 3.0 with a long thread (SH). The bones with simulated @entity174 and implanted screws were loaded uniaxially into flexion for 2000 cycles with a constant bending moment of 800 Nmm. The angulation of the @entity174 fragments was measured continuously. Data were assessed statistically using the univariate ANOVA test and linear regression analysis, and the significance level was set at p < 0.05. RESULTS: The median angulation of bone fragments    allowed by each screw was 0.89   for AA, 1.12   for ST, 1.44   for SH and 2.36   for @entity2100 . With regards to linear regression, the most reliable curve was achieved by @entity2100 , with a coefficient of determination of R2 = 0.827. This was followed by AA (R2 = 0.354), SH (R2 = 0.247) and ST (R2 = 0.019). Data assessed using an adapted ANOVA model showed no statistically significant difference (p = 0.291) between the screws. CONCLUSIONS: The continuous development of HCSs has resulted in very comparable implants, and thus, at this time, other factors, such as surgeons' experience, ease of handling and price, should be taken into consideration.

Impact of Different Screw Designs on Durability of XXXX Fixation: In Vitro Study with Cyclic Loading of Scaphoid Bones.

@entity2100 :: ('MESH:D005600', 'Disease') :: ['MH', 'Martin HBS2 midi'] @entity174 :: ('MESH:D050723', 'Disease') :: ['fracture', 'fractures']
@entity174 :: (MESH:D050723,Disease) :: ['Fracture']
