Antegrade anterior column acetabulum fracture fixation with cannulated compression headless screws - A biomechanical study on standardized osteoporotic artificial bone

NOTICE: The original data files published on September 27, 2019, have been
removed due to non-compliance with Dryad guidelines for publishing human
subjects data. ************** Purpose Due to the increase in life
expectancy and high-energy traumas, anterior column acetabular fractures
(ACFs) are also increasing. While open reduction and internal fixation
(ORIF) is still the standard surgical procedure, minimally invasive,
percutaneous fixation of osteoporotic acetabulum fractures (AF) are
growing in popularity. The aim of this biomechanical study was to evaluate
the biomechanical competence following antegrade fixation with a standard
screw versus a cannulated compression headless screw. Methods Eight
anatomical osteoporotic composite pelvises were given an anterior column
fracture. Two groups of eight specimens each (n = 8) for fixation with
either a 6.5 mm cannulated compression headless screw in group Anterior
Acetabulum Canulated Compression Headless Screw (AACCH), or with a 6.5 mm
partially threaded cannulated screw in group Anterior Acetabulum Standard
Screw (AASS) where compared. Each specimen was biomechanically loaded
cyclically at a rate of 2 Hz with monotonically increasing compressive
load until failure. Motions were assessed by means of optical motion
tracking. Results Initial construct stiffness trended higher in group
AACCH at 152.4 ± 23.1 N/mm compared to group AASS at 118.5 ± 34.3 N/mm, p
= 0.051. Numbers of cycles and corresponding peak load at failure, were
significantly higher in group AACCH at 6734 ± 1669 cycles and 873.4 ±
166.9 N versus group AASS at 4440 ± 2063 cycles and 644.0 ± 206.3 N, p =
0.041. Failure modes were breakout of the screws around the proximal entry
point. Conclusion From a biomechanical perspective, group AACCH was
associated with superior biomechanical competence compared to standard
partially threaded cannulated screws and could therefore be considered as
valid alternative for fixation of anterior acetabulum fractures.